[PATCH v2 00/18] Improve PCI memory mapping API

[PATCH v2 00/18] Improve PCI memory mapping API

[Damien Le Moal]

This series introduces the new functions pci_epc_map_align(),
pci_epc_mem_map() and pci_epc_mem_unmap() to improve handling of the
PCI address mapping alignment constraints of endpoint controllers in a
controller independent manner.

The issue fixed is that the fixed alignment defined by the "align" field
of struct pci_epc_features assumes that the alignment of the endpoint
memory used to map a RC PCI address range is independent of the PCI
address being mapped. But that is not the case for the rk3399 SoC
controller: in endpoint mode, this controller uses the lower bits of the
local endpoint memory address as the lower bits for the PCI addresses
for data transfers. That is, when mapping local memory, one must take
into account the number of bits of the RC PCI address that change from
the start address of the mapping.

To fix this, the new endpoint controller method .map_align is introduced
and called from pci_epc_map_align(). This method is optional and for
controllers that do not define it, the mapping information returned
is based of the fixed alignment constraint as defined by the align
feature.

The functions pci_epc_mem_map() is a helper function which obtains
mapping information, allocates endpoint controller memory according to
the mapping size obtained and maps the memory. pci_epc_mem_map() unmaps
and frees the endpoint memory.

This series is organized as follows:
 - Patch 1 tidy up the epc core code
 - Patch 2 and 3 introduce the new map_align endpoint controller method
   and related epc functions.
 - Patch 4 to 6 modify the test endpoint driver to use these new
   functions and improve the code of this driver.
 - Finally, Patch 7 to 18 fix the rk3399 endpoint driver, defining a
   .map_align method for it and improving its overall code readability
   and features.

Changes from v1:
 - Changed pci_epc_check_func() to pci_epc_function_is_valid() in patch
   1.
 - Removed patch "PCI: endpoint: Improve pci_epc_mem_alloc_addr()"
   (former patch 2 of v1)
 - Various typos cleanups all over. Also fixed some blank space
   indentation.
 - Added review tags

Damien Le Moal (17):
  PCI: endpoint: Introduce pci_epc_function_is_valid()
  PCI: endpoint: Introduce pci_epc_map_align()
  PCI: endpoint: Introduce pci_epc_mem_map()/unmap()
  PCI: endpoint: test: Use pci_epc_mem_map/unmap()
  PCI: endpoint: test: Synchronously cancel command handler work
  PCI: endpoint: test: Implement link_down event operation
  PCI: rockchip-ep: Fix address translation unit programming
  PCI: rockchip-ep: Use a macro to define EP controller .align feature
  PCI: rockchip-ep: Improve rockchip_pcie_ep_unmap_addr()
  PCI: rockchip-ep: Improve rockchip_pcie_ep_map_addr()
  PCI: rockchip-ep: Implement the map_align endpoint controller operation
  PCI: rockchip-ep: Refactor rockchip_pcie_ep_probe() memory allocations
  PCI: rockchip-ep: Refactor rockchip_pcie_ep_probe() MSI-X hiding
  PCI: rockchip-ep: Refactor endpoint link training enable
  PCI: rockship-ep: Introduce rockchip_pcie_ep_stop()
  PCI: rockchip-ep: Improve link training
  PCI: rockchip-ep: Handle PERST# signal in endpoint mode

Wilfred Mallawa (1):
  dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

 .../bindings/pci/rockchip,rk3399-pcie-ep.yaml |   3 +
 drivers/pci/controller/pcie-rockchip-ep.c     | 393 ++++++++++++++----
 drivers/pci/controller/pcie-rockchip.c        |  17 +-
 drivers/pci/controller/pcie-rockchip.h        |  22 +
 drivers/pci/endpoint/functions/pci-epf-test.c | 390 +++++++++--------
 drivers/pci/endpoint/pci-epc-core.c           | 213 +++++++---
 include/linux/pci-epc.h                       |  39 ++
 7 files changed, 768 insertions(+), 309 deletions(-)

-- 
2.44.0

[PATCH v2 01/18] PCI: endpoint: Introduce pci_epc_function_is_valid()

[Damien Le Moal]

Introduce the epc core helper function pci_epc_function_is_valid() to
verify that an epc pointer, a physical function number and a virtual
function number are all valid. This avoids repeating the code pattern:

if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
	return err;

if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
	return err;

in many functions of the endpoint controller core code.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/endpoint/pci-epc-core.c | 79 +++++++++++------------------
 1 file changed, 31 insertions(+), 48 deletions(-)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index da3fc0795b0b..754afd115bbd 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -126,6 +126,18 @@ enum pci_barno pci_epc_get_next_free_bar(const struct pci_epc_features
 }
 EXPORT_SYMBOL_GPL(pci_epc_get_next_free_bar);
 
+static inline bool pci_epc_function_is_valid(struct pci_epc *epc,
+					     u8 func_no, u8 vfunc_no)
+{
+	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
+		return false;
+
+	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+		return false;
+
+	return true;
+}
+
 /**
  * pci_epc_get_features() - get the features supported by EPC
  * @epc: the features supported by *this* EPC device will be returned
@@ -143,10 +155,7 @@ const struct pci_epc_features *pci_epc_get_features(struct pci_epc *epc,
 {
 	const struct pci_epc_features *epc_features;
 
-	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
-		return NULL;
-
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
 		return NULL;
 
 	if (!epc->ops->get_features)
@@ -216,10 +225,7 @@ int pci_epc_raise_irq(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 {
 	int ret;
 
-	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
-		return -EINVAL;
-
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
 		return -EINVAL;
 
 	if (!epc->ops->raise_irq)
@@ -260,10 +266,7 @@ int pci_epc_map_msi_irq(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 {
 	int ret;
 
-	if (IS_ERR_OR_NULL(epc))
-		return -EINVAL;
-
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
 		return -EINVAL;
 
 	if (!epc->ops->map_msi_irq)
@@ -291,10 +294,7 @@ int pci_epc_get_msi(struct pci_epc *epc, u8 func_no, u8 vfunc_no)
 {
 	int interrupt;
 
-	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
-		return 0;
-
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
 		return 0;
 
 	if (!epc->ops->get_msi)
@@ -327,11 +327,10 @@ int pci_epc_set_msi(struct pci_epc *epc, u8 func_no, u8 vfunc_no, u8 interrupts)
 	int ret;
 	u8 encode_int;
 
-	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions ||
-	    interrupts < 1 || interrupts > 32)
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
 		return -EINVAL;
 
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+	if (interrupts < 1 || interrupts > 32)
 		return -EINVAL;
 
 	if (!epc->ops->set_msi)
@@ -359,10 +358,7 @@ int pci_epc_get_msix(struct pci_epc *epc, u8 func_no, u8 vfunc_no)
 {
 	int interrupt;
 
-	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
-		return 0;
-
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
 		return 0;
 
 	if (!epc->ops->get_msix)
@@ -395,11 +391,10 @@ int pci_epc_set_msix(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 {
 	int ret;
 
-	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions ||
-	    interrupts < 1 || interrupts > 2048)
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
 		return -EINVAL;
 
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+	if (interrupts < 1 || interrupts > 2048)
 		return -EINVAL;
 
 	if (!epc->ops->set_msix)
@@ -426,10 +421,7 @@ EXPORT_SYMBOL_GPL(pci_epc_set_msix);
 void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 			phys_addr_t phys_addr)
 {
-	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
-		return;
-
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
 		return;
 
 	if (!epc->ops->unmap_addr)
@@ -457,10 +449,7 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 {
 	int ret;
 
-	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
-		return -EINVAL;
-
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
 		return -EINVAL;
 
 	if (!epc->ops->map_addr)
@@ -487,12 +476,11 @@ EXPORT_SYMBOL_GPL(pci_epc_map_addr);
 void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 		       struct pci_epf_bar *epf_bar)
 {
-	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions ||
-	    (epf_bar->barno == BAR_5 &&
-	     epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64))
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
 		return;
 
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+	if (epf_bar->barno == BAR_5 &&
+	    epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64)
 		return;
 
 	if (!epc->ops->clear_bar)
@@ -519,18 +507,16 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 	int ret;
 	int flags = epf_bar->flags;
 
-	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions ||
-	    (epf_bar->barno == BAR_5 &&
-	     flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ||
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
+		return -EINVAL;
+
+	if ((epf_bar->barno == BAR_5 && flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ||
 	    (flags & PCI_BASE_ADDRESS_SPACE_IO &&
 	     flags & PCI_BASE_ADDRESS_IO_MASK) ||
 	    (upper_32_bits(epf_bar->size) &&
 	     !(flags & PCI_BASE_ADDRESS_MEM_TYPE_64)))
 		return -EINVAL;
 
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
-		return -EINVAL;
-
 	if (!epc->ops->set_bar)
 		return 0;
 
@@ -559,10 +545,7 @@ int pci_epc_write_header(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 {
 	int ret;
 
-	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
-		return -EINVAL;
-
-	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
 		return -EINVAL;
 
 	/* Only Virtual Function #1 has deviceID */
-- 
2.44.0

[PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()

[Damien Le Moal]

Some endpoint controllers have requirements on the alignment of the
controller physical memory address that must be used to map a RC PCI
address region. For instance, the rockchip endpoint controller uses
at most the lower 20 bits of a physical memory address region as the
lower bits of an RC PCI address. For mapping a PCI address region of
size bytes starting from pci_addr, the exact number of address bits
used is the number of address bits changing in the address range
[pci_addr..pci_addr + size - 1].

For this example, this creates the following constraints:
1) The offset into the controller physical memory allocated for a
   mapping depends on the mapping size *and* the starting PCI address
   for the mapping.
2) A mapping size cannot exceed the controller windows size (1MB) minus
   the offset needed into the allocated physical memory, which can end
   up being a smaller size than the desired mapping size.

Handling these constraints independently of the controller being used in
a PCI EP function driver is not possible with the current EPC API as
it only provides the ->align field in struct pci_epc_features.
Furthermore, this alignment is static and does not depend on a mapping
pci address and size.

Solve this by introducing the function pci_epc_map_align() and the
endpoint controller operation ->map_align to allow endpoint function
drivers to obtain the size and the offset into a controller address
region that must be used to map an RC PCI address region. The size
of the physical address region provided by pci_epc_map_align() can then
be used as the size argument for the function pci_epc_mem_alloc_addr().
The offset into the allocated controller memory can be used to
correctly handle data transfers. Of note is that pci_epc_map_align() may
indicate upon return a mapping size that is smaller (but not 0) than the
requested PCI address region size. For such case, an endpoint function
driver must handle data transfers in fragments.

The controller operation ->map_align is optional: controllers that do
not have any address alignment constraints for mapping a RC PCI address
region do not need to implement this operation. For such controllers,
pci_epc_map_align() always returns the mapping size as equal
to the requested size and an offset equal to 0.

The structure pci_epc_map is introduced to represent a mapping start PCI
address, size and the size and offset into the controller memory needed
for mapping the PCI address region.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/endpoint/pci-epc-core.c | 66 +++++++++++++++++++++++++++++
 include/linux/pci-epc.h             | 33 +++++++++++++++
 2 files changed, 99 insertions(+)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 754afd115bbd..37758ca91d7f 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -433,6 +433,72 @@ void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 }
 EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
 
+/**
+ * pci_epc_map_align() - Get the offset into and the size of a controller memory
+ *			 address region needed to map a RC PCI address region
+ * @epc: the EPC device on which address is allocated
+ * @func_no: the physical endpoint function number in the EPC device
+ * @vfunc_no: the virtual endpoint function number in the physical function
+ * @pci_addr: PCI address to which the physical address should be mapped
+ * @size: the size of the mapping starting from @pci_addr
+ * @map: populate here the actual size and offset into the controller memory
+ *       that must be allocated for the mapping
+ *
+ * Invoke the controller map_align operation to obtain the size and the offset
+ * into a controller address region that must be allocated to map @size
+ * bytes of the RC PCI address space starting from @pci_addr.
+ *
+ * The size of the mapping that can be handled by the controller is indicated
+ * using the pci_size field of @map. This size may be smaller than the requested
+ * @size. In such case, the function driver must handle the mapping using
+ * several fragments. The offset into the controller memory for the effective
+ * mapping of the @pci_addr..@pci_addr+@map->pci_size address range is indicated
+ * using the map_ofst field of @map.
+ */
+int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+		      u64 pci_addr, size_t size, struct pci_epc_map *map)
+{
+	const struct pci_epc_features *features;
+	size_t mask;
+	int ret;
+
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
+		return -EINVAL;
+
+	if (!size || !map)
+		return -EINVAL;
+
+	memset(map, 0, sizeof(*map));
+	map->pci_addr = pci_addr;
+	map->pci_size = size;
+
+	if (epc->ops->map_align) {
+		mutex_lock(&epc->lock);
+		ret = epc->ops->map_align(epc, func_no, vfunc_no, map);
+		mutex_unlock(&epc->lock);
+		return ret;
+	}
+
+	/*
+	 * Assume a fixed alignment constraint as specified by the controller
+	 * features.
+	 */
+	features = pci_epc_get_features(epc, func_no, vfunc_no);
+	if (!features || !features->align) {
+		map->map_pci_addr = pci_addr;
+		map->map_size = size;
+		map->map_ofst = 0;
+	}
+
+	mask = features->align - 1;
+	map->map_pci_addr = map->pci_addr & ~mask;
+	map->map_ofst = map->pci_addr & mask;
+	map->map_size = ALIGN(map->map_ofst + map->pci_size, features->align);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pci_epc_map_align);
+
 /**
  * pci_epc_map_addr() - map CPU address to PCI address
  * @epc: the EPC device on which address is allocated
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index cc2f70d061c8..8cfb4aaf2628 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -32,11 +32,40 @@ pci_epc_interface_string(enum pci_epc_interface_type type)
 	}
 }
 
+/**
+ * struct pci_epc_map - information about EPC memory for mapping a RC PCI
+ *                      address range
+ * @pci_addr: start address of the RC PCI address range to map
+ * @pci_size: size of the RC PCI address range to map
+ * @map_pci_addr: RC PCI address used as the first address mapped
+ * @map_size: size of the controller memory needed for the mapping
+ * @map_ofst: offset into the controller memory needed for the mapping
+ * @phys_base: base physical address of the allocated EPC memory
+ * @phys_addr: physical address at which @pci_addr is mapped
+ * @virt_base: base virtual address of the allocated EPC memory
+ * @virt_addr: virtual address at which @pci_addr is mapped
+ */
+struct pci_epc_map {
+	phys_addr_t	pci_addr;
+	size_t		pci_size;
+
+	phys_addr_t	map_pci_addr;
+	size_t		map_size;
+	phys_addr_t	map_ofst;
+
+	phys_addr_t	phys_base;
+	phys_addr_t	phys_addr;
+	void __iomem	*virt_base;
+	void __iomem	*virt_addr;
+};
+
 /**
  * struct pci_epc_ops - set of function pointers for performing EPC operations
  * @write_header: ops to populate configuration space header
  * @set_bar: ops to configure the BAR
  * @clear_bar: ops to reset the BAR
+ * @map_align: operation to get the size and offset into a controller memory
+ *             window needed to map an RC PCI address region
  * @map_addr: ops to map CPU address to PCI address
  * @unmap_addr: ops to unmap CPU address and PCI address
  * @set_msi: ops to set the requested number of MSI interrupts in the MSI
@@ -61,6 +90,8 @@ struct pci_epc_ops {
 			   struct pci_epf_bar *epf_bar);
 	void	(*clear_bar)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 			     struct pci_epf_bar *epf_bar);
+	int	(*map_align)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+			    struct pci_epc_map *map);
 	int	(*map_addr)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 			    phys_addr_t addr, u64 pci_addr, size_t size);
 	void	(*unmap_addr)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
@@ -234,6 +265,8 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 		    struct pci_epf_bar *epf_bar);
 void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 		       struct pci_epf_bar *epf_bar);
+int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+		      u64 pci_addr, size_t size, struct pci_epc_map *map);
 int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 		     phys_addr_t phys_addr,
 		     u64 pci_addr, size_t size);
-- 
2.44.0

[PATCH v2 03/18] PCI: endpoint: Introduce pci_epc_mem_map()/unmap()

[Damien Le Moal]

Introduce the function pci_epc_mem_map() to facilitate controller memory
address allocation and mapping to a RC PCI address region in endpoint
function drivers.

This function first uses pci_epc_map_align() to determine the controller
memory address alignment (offset and size) constraints. The result of
this function is used to allocate a controller physical memory region
using pci_epc_mem_alloc_addr() and map it to the RC PCI address
space with pci_epc_map_addr(). Since pci_epc_map_align() may indicate
that a mapping can be smaller than the requested size, pci_epc_mem_map()
may only partially map the RC PCI address region specified and return
a smaller size for the effective mapping.

The counterpart of pci_epc_mem_map() to unmap and free the controller
memory address region is pci_epc_mem_unmap().

Both functions operate using struct pci_epc_map data structure which is
extended to contain the physical and virtual addresses of the allocated
controller memory. Endpoint function drivers can use struct pci_epc_map
to implement read/write accesses within the mapped RC PCI address region
using the ->virt_addr and ->size fields.

This commit contains contributions from Rick Wertenbroek
<rick.wertenbroek@gmail.com>.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/endpoint/pci-epc-core.c | 68 +++++++++++++++++++++++++++++
 include/linux/pci-epc.h             |  6 +++
 2 files changed, 74 insertions(+)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 37758ca91d7f..0095b54bdf9e 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -530,6 +530,74 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 }
 EXPORT_SYMBOL_GPL(pci_epc_map_addr);
 
+/**
+ * pci_epc_mem_map() - allocate and map CPU address to PCI address
+ * @epc: the EPC device on which the CPU address is to be allocated and mapped
+ * @func_no: the physical endpoint function number in the EPC device
+ * @vfunc_no: the virtual endpoint function number in the physical function
+ * @pci_addr: PCI address to which the CPU address should be mapped
+ * @size: the number of bytes to map starting from @pci_addr
+ * @map: where to return the mapping information
+ *
+ * Allocate a controller physical address region and map it to a RC PCI address
+ * region, taking into account the controller physical address mapping
+ * constraints (if any). Returns the effective size of the mapping, which may
+ * be less than @size, or a negative error code in case of error.
+ */
+ssize_t pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+			u64 pci_addr, size_t size, struct pci_epc_map *map)
+{
+	int ret;
+
+	ret = pci_epc_map_align(epc, func_no, vfunc_no, pci_addr, size, map);
+	if (ret)
+		return ret;
+
+	map->virt_base = pci_epc_mem_alloc_addr(epc, &map->phys_base,
+						map->map_size);
+	if (!map->virt_base)
+		return -ENOMEM;
+
+	map->phys_addr = map->phys_base + map->map_ofst;
+	map->virt_addr = map->virt_base + map->map_ofst;
+
+	ret = pci_epc_map_addr(epc, func_no, vfunc_no, map->phys_base,
+			       map->map_pci_addr, map->map_size);
+	if (ret) {
+		pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
+				      map->map_size);
+		return ret;
+	}
+
+	return map->pci_size;
+}
+EXPORT_SYMBOL_GPL(pci_epc_mem_map);
+
+/**
+ * pci_epc_mem_unmap() - unmap from PCI address and free a CPU address region
+ * @epc: the EPC device on which the CPU address is allocated and mapped
+ * @func_no: the physical endpoint function number in the EPC device
+ * @vfunc_no: the virtual endpoint function number in the physical function
+ * @map: the mapping information
+ *
+ * Allocate and map local CPU address to a PCI address, accounting for the
+ * controller local CPU address alignment constraints.
+ */
+void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+		       struct pci_epc_map *map)
+{
+	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
+		return;
+
+	if (!map || !map->pci_size)
+		return;
+
+	pci_epc_unmap_addr(epc, func_no, vfunc_no, map->phys_base);
+	pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
+			      map->map_size);
+}
+EXPORT_SYMBOL_GPL(pci_epc_mem_unmap);
+
 /**
  * pci_epc_clear_bar() - reset the BAR
  * @epc: the EPC device for which the BAR has to be cleared
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index 8cfb4aaf2628..86397a500b54 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -304,4 +304,10 @@ void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
 				     phys_addr_t *phys_addr, size_t size);
 void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
 			   void __iomem *virt_addr, size_t size);
+
+ssize_t pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+			u64 pci_addr, size_t size, struct pci_epc_map *map);
+void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
+		       struct pci_epc_map *map);
+
 #endif /* __LINUX_PCI_EPC_H */
-- 
2.44.0

[PATCH v2 04/18] PCI: endpoint: test: Use pci_epc_mem_map/unmap()

[Damien Le Moal]

Modify the endpoint test driver to use the functions pci_epc_mem_map()
and pci_epc_mem_unmap() for the read, write and copy tests. For each
test case, the transfer (dma or mmio) are executed in a loop to ensure
that potentially partial mappings returned by pci_epc_mem_map() are
correctly handled.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/endpoint/functions/pci-epf-test.c | 378 +++++++++---------
 1 file changed, 197 insertions(+), 181 deletions(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index cd4ffb39dcdc..0e285e539538 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -317,91 +317,94 @@ static void pci_epf_test_print_rate(struct pci_epf_test *epf_test,
 static void pci_epf_test_copy(struct pci_epf_test *epf_test,
 			      struct pci_epf_test_reg *reg)
 {
-	int ret;
-	void __iomem *src_addr;
-	void __iomem *dst_addr;
-	phys_addr_t src_phys_addr;
-	phys_addr_t dst_phys_addr;
+	int ret = 0;
 	struct timespec64 start, end;
 	struct pci_epf *epf = epf_test->epf;
-	struct device *dev = &epf->dev;
 	struct pci_epc *epc = epf->epc;
+	struct device *dev = &epf->dev;
+	struct pci_epc_map src_map, dst_map;
+	u64 src_addr = reg->src_addr;
+	u64 dst_addr = reg->dst_addr;
+	size_t copy_size = reg->size;
+	ssize_t map_size = 0;
+	void *copy_buf = NULL, *buf;
 
-	src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr, reg->size);
-	if (!src_addr) {
-		dev_err(dev, "Failed to allocate source address\n");
-		reg->status = STATUS_SRC_ADDR_INVALID;
-		ret = -ENOMEM;
-		goto err;
-	}
-
-	ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, src_phys_addr,
-			       reg->src_addr, reg->size);
-	if (ret) {
-		dev_err(dev, "Failed to map source address\n");
-		reg->status = STATUS_SRC_ADDR_INVALID;
-		goto err_src_addr;
-	}
-
-	dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr, reg->size);
-	if (!dst_addr) {
-		dev_err(dev, "Failed to allocate destination address\n");
-		reg->status = STATUS_DST_ADDR_INVALID;
-		ret = -ENOMEM;
-		goto err_src_map_addr;
-	}
-
-	ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, dst_phys_addr,
-			       reg->dst_addr, reg->size);
-	if (ret) {
-		dev_err(dev, "Failed to map destination address\n");
-		reg->status = STATUS_DST_ADDR_INVALID;
-		goto err_dst_addr;
-	}
-
-	ktime_get_ts64(&start);
 	if (reg->flags & FLAG_USE_DMA) {
 		if (epf_test->dma_private) {
 			dev_err(dev, "Cannot transfer data using DMA\n");
 			ret = -EINVAL;
-			goto err_map_addr;
+			goto set_status;
 		}
-
-		ret = pci_epf_test_data_transfer(epf_test, dst_phys_addr,
-						 src_phys_addr, reg->size, 0,
-						 DMA_MEM_TO_MEM);
-		if (ret)
-			dev_err(dev, "Data transfer failed\n");
 	} else {
-		void *buf;
-
-		buf = kzalloc(reg->size, GFP_KERNEL);
-		if (!buf) {
+		copy_buf = kzalloc(copy_size, GFP_KERNEL);
+		if (!copy_buf) {
 			ret = -ENOMEM;
-			goto err_map_addr;
+			goto set_status;
 		}
-
-		memcpy_fromio(buf, src_addr, reg->size);
-		memcpy_toio(dst_addr, buf, reg->size);
-		kfree(buf);
+		buf = copy_buf;
 	}
-	ktime_get_ts64(&end);
-	pci_epf_test_print_rate(epf_test, "COPY", reg->size, &start, &end,
-				reg->flags & FLAG_USE_DMA);
 
-err_map_addr:
-	pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, dst_phys_addr);
+	while (copy_size) {
+		map_size = pci_epc_mem_map(epc, epf->func_no, epf->vfunc_no,
+					   src_addr, copy_size, &src_map);
+		if (map_size < 0) {
+			dev_err(dev, "Failed to map source address\n");
+			reg->status = STATUS_SRC_ADDR_INVALID;
+			ret = map_size;
+			goto free_buf;
+		}
+
+		map_size = pci_epc_mem_map(epf->epc, epf->func_no, epf->vfunc_no,
+					   dst_addr, copy_size, &dst_map);
+		if (map_size < 0) {
+			dev_err(dev, "Failed to map destination address\n");
+			reg->status = STATUS_DST_ADDR_INVALID;
+			ret = map_size;
+			pci_epc_mem_unmap(epc, epf->func_no, epf->vfunc_no,
+					  &src_map);
+			goto free_buf;
+		}
+
+		map_size = min_t(size_t, map_size, src_map.pci_size);
+
+		ktime_get_ts64(&start);
+		if (reg->flags & FLAG_USE_DMA) {
+			ret = pci_epf_test_data_transfer(epf_test,
+					dst_map.phys_addr, src_map.phys_addr,
+					map_size, 0, DMA_MEM_TO_MEM);
+			if (ret) {
+				dev_err(dev, "Data transfer failed\n");
+				goto unmap;
+			}
+		} else {
+			memcpy_fromio(buf, src_map.virt_addr, map_size);
+			memcpy_toio(dst_map.virt_addr, buf, map_size);
+			buf += map_size;
+		}
+		ktime_get_ts64(&end);
+
+		copy_size -= map_size;
+		src_addr += map_size;
+		dst_addr += map_size;
 
-err_dst_addr:
-	pci_epc_mem_free_addr(epc, dst_phys_addr, dst_addr, reg->size);
+		pci_epc_mem_unmap(epc, epf->func_no, epf->vfunc_no, &dst_map);
+		pci_epc_mem_unmap(epc, epf->func_no, epf->vfunc_no, &src_map);
+		map_size = 0;
+	}
 
-err_src_map_addr:
-	pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, src_phys_addr);
+	pci_epf_test_print_rate(epf_test, "COPY", reg->size, &start,
+				&end, reg->flags & FLAG_USE_DMA);
+
+unmap:
+	if (map_size) {
+		pci_epc_mem_unmap(epc, epf->func_no, epf->vfunc_no, &dst_map);
+		pci_epc_mem_unmap(epc, epf->func_no, epf->vfunc_no, &src_map);
+	}
 
-err_src_addr:
-	pci_epc_mem_free_addr(epc, src_phys_addr, src_addr, reg->size);
+free_buf:
+	kfree(copy_buf);
 
-err:
+set_status:
 	if (!ret)
 		reg->status |= STATUS_COPY_SUCCESS;
 	else
@@ -411,82 +414,89 @@ static void pci_epf_test_copy(struct pci_epf_test *epf_test,
 static void pci_epf_test_read(struct pci_epf_test *epf_test,
 			      struct pci_epf_test_reg *reg)
 {
-	int ret;
-	void __iomem *src_addr;
-	void *buf;
+	int ret = 0;
+	void *src_buf, *buf;
 	u32 crc32;
-	phys_addr_t phys_addr;
+	struct pci_epc_map map;
 	phys_addr_t dst_phys_addr;
 	struct timespec64 start, end;
 	struct pci_epf *epf = epf_test->epf;
-	struct device *dev = &epf->dev;
 	struct pci_epc *epc = epf->epc;
+	struct device *dev = &epf->dev;
 	struct device *dma_dev = epf->epc->dev.parent;
+	u64 src_addr = reg->src_addr;
+	size_t src_size = reg->size;
+	ssize_t map_size = 0;
 
-	src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
-	if (!src_addr) {
-		dev_err(dev, "Failed to allocate address\n");
-		reg->status = STATUS_SRC_ADDR_INVALID;
+	src_buf = kzalloc(src_size, GFP_KERNEL);
+	if (!src_buf) {
 		ret = -ENOMEM;
-		goto err;
-	}
-
-	ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, phys_addr,
-			       reg->src_addr, reg->size);
-	if (ret) {
-		dev_err(dev, "Failed to map address\n");
-		reg->status = STATUS_SRC_ADDR_INVALID;
-		goto err_addr;
-	}
-
-	buf = kzalloc(reg->size, GFP_KERNEL);
-	if (!buf) {
-		ret = -ENOMEM;
-		goto err_map_addr;
+		goto set_status;
 	}
+	buf = src_buf;
+
+	while (src_size) {
+		map_size = pci_epc_mem_map(epc, epf->func_no, epf->vfunc_no,
+					   src_addr, src_size, &map);
+		if (map_size < 0) {
+			dev_err(dev, "Failed to map address\n");
+			reg->status = STATUS_SRC_ADDR_INVALID;
+			ret = map_size;
+			goto free_buf;
+		}
 
-	if (reg->flags & FLAG_USE_DMA) {
-		dst_phys_addr = dma_map_single(dma_dev, buf, reg->size,
-					       DMA_FROM_DEVICE);
-		if (dma_mapping_error(dma_dev, dst_phys_addr)) {
-			dev_err(dev, "Failed to map destination buffer addr\n");
-			ret = -ENOMEM;
-			goto err_dma_map;
+		if (reg->flags & FLAG_USE_DMA) {
+			dst_phys_addr = dma_map_single(dma_dev, buf, map_size,
+						       DMA_FROM_DEVICE);
+			if (dma_mapping_error(dma_dev, dst_phys_addr)) {
+				dev_err(dev,
+					"Failed to map destination buffer addr\n");
+				ret = -ENOMEM;
+				goto unmap;
+			}
+
+			ktime_get_ts64(&start);
+			ret = pci_epf_test_data_transfer(epf_test,
+					dst_phys_addr, map.phys_addr,
+					map_size, src_addr, DMA_DEV_TO_MEM);
+			if (ret)
+				dev_err(dev, "Data transfer failed\n");
+			ktime_get_ts64(&end);
+
+			dma_unmap_single(dma_dev, dst_phys_addr, map_size,
+					 DMA_FROM_DEVICE);
+
+			if (ret)
+				goto unmap;
+		} else {
+			ktime_get_ts64(&start);
+			memcpy_fromio(buf, map.virt_addr, map_size);
+			ktime_get_ts64(&end);
 		}
 
-		ktime_get_ts64(&start);
-		ret = pci_epf_test_data_transfer(epf_test, dst_phys_addr,
-						 phys_addr, reg->size,
-						 reg->src_addr, DMA_DEV_TO_MEM);
-		if (ret)
-			dev_err(dev, "Data transfer failed\n");
-		ktime_get_ts64(&end);
+		src_size -= map_size;
+		src_addr += map_size;
+		buf += map_size;
 
-		dma_unmap_single(dma_dev, dst_phys_addr, reg->size,
-				 DMA_FROM_DEVICE);
-	} else {
-		ktime_get_ts64(&start);
-		memcpy_fromio(buf, src_addr, reg->size);
-		ktime_get_ts64(&end);
+		pci_epc_mem_unmap(epc, epf->func_no, epf->vfunc_no, &map);
+		map_size = 0;
 	}
 
-	pci_epf_test_print_rate(epf_test, "READ", reg->size, &start, &end,
-				reg->flags & FLAG_USE_DMA);
+	pci_epf_test_print_rate(epf_test, "READ", reg->size, &start,
+				&end, reg->flags & FLAG_USE_DMA);
 
-	crc32 = crc32_le(~0, buf, reg->size);
+	crc32 = crc32_le(~0, src_buf, reg->size);
 	if (crc32 != reg->checksum)
 		ret = -EIO;
 
-err_dma_map:
-	kfree(buf);
+unmap:
+	if (map_size)
+		pci_epc_mem_unmap(epc, epf->func_no, epf->vfunc_no, &map);
 
-err_map_addr:
-	pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, phys_addr);
+free_buf:
+	kfree(src_buf);
 
-err_addr:
-	pci_epc_mem_free_addr(epc, phys_addr, src_addr, reg->size);
-
-err:
+set_status:
 	if (!ret)
 		reg->status |= STATUS_READ_SUCCESS;
 	else
@@ -496,71 +506,79 @@ static void pci_epf_test_read(struct pci_epf_test *epf_test,
 static void pci_epf_test_write(struct pci_epf_test *epf_test,
 			       struct pci_epf_test_reg *reg)
 {
-	int ret;
-	void __iomem *dst_addr;
-	void *buf;
-	phys_addr_t phys_addr;
+	int ret = 0;
+	void *dst_buf, *buf;
+	struct pci_epc_map map;
 	phys_addr_t src_phys_addr;
 	struct timespec64 start, end;
 	struct pci_epf *epf = epf_test->epf;
-	struct device *dev = &epf->dev;
 	struct pci_epc *epc = epf->epc;
+	struct device *dev = &epf->dev;
 	struct device *dma_dev = epf->epc->dev.parent;
+	u64 dst_addr = reg->dst_addr;
+	size_t dst_size = reg->size;
+	ssize_t map_size = 0;
 
-	dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
-	if (!dst_addr) {
-		dev_err(dev, "Failed to allocate address\n");
-		reg->status = STATUS_DST_ADDR_INVALID;
+	dst_buf = kzalloc(dst_size, GFP_KERNEL);
+	if (!dst_buf) {
 		ret = -ENOMEM;
-		goto err;
+		goto set_status;
 	}
-
-	ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, phys_addr,
-			       reg->dst_addr, reg->size);
-	if (ret) {
-		dev_err(dev, "Failed to map address\n");
-		reg->status = STATUS_DST_ADDR_INVALID;
-		goto err_addr;
-	}
-
-	buf = kzalloc(reg->size, GFP_KERNEL);
-	if (!buf) {
-		ret = -ENOMEM;
-		goto err_map_addr;
-	}
-
-	get_random_bytes(buf, reg->size);
-	reg->checksum = crc32_le(~0, buf, reg->size);
-
-	if (reg->flags & FLAG_USE_DMA) {
-		src_phys_addr = dma_map_single(dma_dev, buf, reg->size,
-					       DMA_TO_DEVICE);
-		if (dma_mapping_error(dma_dev, src_phys_addr)) {
-			dev_err(dev, "Failed to map source buffer addr\n");
-			ret = -ENOMEM;
-			goto err_dma_map;
+	get_random_bytes(dst_buf, dst_size);
+	reg->checksum = crc32_le(~0, dst_buf, dst_size);
+	buf = dst_buf;
+
+	while (dst_size) {
+		map_size = pci_epc_mem_map(epc, epf->func_no, epf->vfunc_no,
+					   dst_addr, dst_size, &map);
+		if (map_size < 0) {
+			dev_err(dev, "Failed to map address\n");
+			reg->status = STATUS_DST_ADDR_INVALID;
+			ret = map_size;
+			goto free_buf;
 		}
 
-		ktime_get_ts64(&start);
+		if (reg->flags & FLAG_USE_DMA) {
+			src_phys_addr = dma_map_single(dma_dev, buf, map_size,
+						       DMA_TO_DEVICE);
+			if (dma_mapping_error(dma_dev, src_phys_addr)) {
+				dev_err(dev,
+					"Failed to map source buffer addr\n");
+				ret = -ENOMEM;
+				goto unmap;
+			}
+
+			ktime_get_ts64(&start);
+
+			ret = pci_epf_test_data_transfer(epf_test,
+						map.phys_addr, src_phys_addr,
+						map_size, dst_addr,
+						DMA_MEM_TO_DEV);
+			if (ret)
+				dev_err(dev, "Data transfer failed\n");
+			ktime_get_ts64(&end);
+
+			dma_unmap_single(dma_dev, src_phys_addr, map_size,
+					 DMA_TO_DEVICE);
+
+			if (ret)
+				goto unmap;
+		} else {
+			ktime_get_ts64(&start);
+			memcpy_toio(map.virt_addr, buf, map_size);
+			ktime_get_ts64(&end);
+		}
 
-		ret = pci_epf_test_data_transfer(epf_test, phys_addr,
-						 src_phys_addr, reg->size,
-						 reg->dst_addr,
-						 DMA_MEM_TO_DEV);
-		if (ret)
-			dev_err(dev, "Data transfer failed\n");
-		ktime_get_ts64(&end);
+		dst_size -= map_size;
+		dst_addr += map_size;
+		buf += map_size;
 
-		dma_unmap_single(dma_dev, src_phys_addr, reg->size,
-				 DMA_TO_DEVICE);
-	} else {
-		ktime_get_ts64(&start);
-		memcpy_toio(dst_addr, buf, reg->size);
-		ktime_get_ts64(&end);
+		pci_epc_mem_unmap(epc, epf->func_no, epf->vfunc_no, &map);
+		map_size = 0;
 	}
 
-	pci_epf_test_print_rate(epf_test, "WRITE", reg->size, &start, &end,
-				reg->flags & FLAG_USE_DMA);
+	pci_epf_test_print_rate(epf_test, "WRITE", reg->size, &start,
+				&end, reg->flags & FLAG_USE_DMA);
 
 	/*
 	 * wait 1ms inorder for the write to complete. Without this delay L3
@@ -568,16 +586,14 @@ static void pci_epf_test_write(struct pci_epf_test *epf_test,
 	 */
 	usleep_range(1000, 2000);
 
-err_dma_map:
-	kfree(buf);
-
-err_map_addr:
-	pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, phys_addr);
+unmap:
+	if (map_size)
+		pci_epc_mem_unmap(epc, epf->func_no, epf->vfunc_no, &map);
 
-err_addr:
-	pci_epc_mem_free_addr(epc, phys_addr, dst_addr, reg->size);
+free_buf:
+	kfree(dst_buf);
 
-err:
+set_status:
 	if (!ret)
 		reg->status |= STATUS_WRITE_SUCCESS;
 	else
-- 
2.44.0

[PATCH v2 05/18] PCI: endpoint: test: Synchronously cancel command handler work

[Damien Le Moal]

Replace the call to cancel_delayed_work() with a call to
cancel_delayed_work_sync() in pci_epf_test_unbind(). This ensures that
the command handler is really stopped when proceeding with dma and bar
cleanup.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 0e285e539538..ab40c3182677 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -709,7 +709,7 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
 	struct pci_epf_bar *epf_bar;
 	int bar;
 
-	cancel_delayed_work(&epf_test->cmd_handler);
+	cancel_delayed_work_sync(&epf_test->cmd_handler);
 	pci_epf_test_clean_dma_chan(epf_test);
 	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
 		epf_bar = &epf->bar[bar];
-- 
2.44.0

[PATCH v2 06/18] PCI: endpoint: test: Implement link_down event operation

[Damien Le Moal]

Implement the link_down event operation to stop the command execution
delayed work when the endpoint controller notifies a link down event.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/pci/endpoint/functions/pci-epf-test.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index ab40c3182677..e6d4e1747c9f 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -824,9 +824,19 @@ static int pci_epf_test_link_up(struct pci_epf *epf)
 	return 0;
 }
 
+static int pci_epf_test_link_down(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+
+	cancel_delayed_work_sync(&epf_test->cmd_handler);
+
+	return 0;
+}
+
 static const struct pci_epc_event_ops pci_epf_test_event_ops = {
 	.core_init = pci_epf_test_core_init,
 	.link_up = pci_epf_test_link_up,
+	.link_down = pci_epf_test_link_down,
 };
 
 static int pci_epf_test_alloc_space(struct pci_epf *epf)
-- 
2.44.0

[PATCH v2 07/18] PCI: rockchip-ep: Fix address translation unit programming

[Damien Le Moal]

The rockchip PCIe endpoint controller handles PCIe transfers addresses
by masking the lower bits of the programmed PCI address and using the
same number of lower bits masked from the CPU address space used for the
mapping. For a PCI mapping of <size> bytes starting from <pci_addr>,
the number of bits masked is the number of address bits changing in the
address range [pci_addr..pci_addr + size - 1].

However, rockchip_pcie_prog_ep_ob_atu() calculates num_pass_bits only
using the size of the mapping, resulting in an incorrect number of mask
bits depending on the value of the PCI address to map.

Fix this by introducing the helper function
rockchip_pcie_ep_ob_atu_num_bits() to correctly calculate the number of
mask bits to use to program the address translation unit. The number of
mask bits iscalculated depending on both the PCI address and size of the
mapping, and clamped between 8 and 20 using the macros
ROCKCHIP_PCIE_AT_MIN_NUM_BITS and ROCKCHIP_PCIE_AT_MAX_NUM_BITS.

Fixes: cf590b078391 ("PCI: rockchip: Add EP driver for Rockchip PCIe controller")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 15 +++++++++++----
 drivers/pci/controller/pcie-rockchip.h    |  4 ++++
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index c9046e97a1d2..786efd918b3f 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -63,16 +63,23 @@ static void rockchip_pcie_clear_ep_ob_atu(struct rockchip_pcie *rockchip,
 			    ROCKCHIP_PCIE_AT_OB_REGION_DESC1(region));
 }
 
+static int rockchip_pcie_ep_ob_atu_num_bits(struct rockchip_pcie *rockchip,
+					    u64 pci_addr, size_t size)
+{
+	int num_pass_bits = fls64(pci_addr ^ (pci_addr + size - 1));
+
+	return clamp(num_pass_bits, ROCKCHIP_PCIE_AT_MIN_NUM_BITS,
+		     ROCKCHIP_PCIE_AT_MAX_NUM_BITS);
+}
+
 static void rockchip_pcie_prog_ep_ob_atu(struct rockchip_pcie *rockchip, u8 fn,
 					 u32 r, u64 cpu_addr, u64 pci_addr,
 					 size_t size)
 {
-	int num_pass_bits = fls64(size - 1);
+	int num_pass_bits =
+		rockchip_pcie_ep_ob_atu_num_bits(rockchip, pci_addr, size);
 	u32 addr0, addr1, desc0;
 
-	if (num_pass_bits < 8)
-		num_pass_bits = 8;
-
 	addr0 = ((num_pass_bits - 1) & PCIE_CORE_OB_REGION_ADDR0_NUM_BITS) |
 		(lower_32_bits(pci_addr) & PCIE_CORE_OB_REGION_ADDR0_LO_ADDR);
 	addr1 = upper_32_bits(pci_addr);
diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
index 6111de35f84c..15ee949f2485 100644
--- a/drivers/pci/controller/pcie-rockchip.h
+++ b/drivers/pci/controller/pcie-rockchip.h
@@ -245,6 +245,10 @@
 	(PCIE_EP_PF_CONFIG_REGS_BASE + (((fn) << 12) & GENMASK(19, 12)))
 #define ROCKCHIP_PCIE_EP_VIRT_FUNC_BASE(fn) \
 	(PCIE_EP_PF_CONFIG_REGS_BASE + 0x10000 + (((fn) << 12) & GENMASK(19, 12)))
+
+#define ROCKCHIP_PCIE_AT_MIN_NUM_BITS  8
+#define ROCKCHIP_PCIE_AT_MAX_NUM_BITS  20
+
 #define ROCKCHIP_PCIE_AT_IB_EP_FUNC_BAR_ADDR0(fn, bar) \
 	(PCIE_CORE_AXI_CONF_BASE + 0x0828 + (fn) * 0x0040 + (bar) * 0x0008)
 #define ROCKCHIP_PCIE_AT_IB_EP_FUNC_BAR_ADDR1(fn, bar) \
-- 
2.44.0

[PATCH v2 08/18] PCI: rockchip-ep: Use a macro to define EP controller .align feature

[Damien Le Moal]

Introduce the macro ROCKCHIP_PCIE_AT_SIZE_ALIGN defined using
ROCKCHIP_PCIE_AT_MIN_NUM_BITS to initialize the .align field of the
controller epc_features structure, avoiding using the "magic" value 8
directly.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 2 +-
 drivers/pci/controller/pcie-rockchip.h    | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index 786efd918b3f..f8c26606df58 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -448,7 +448,7 @@ static const struct pci_epc_features rockchip_pcie_epc_features = {
 	.linkup_notifier = false,
 	.msi_capable = true,
 	.msix_capable = false,
-	.align = 256,
+	.align = ROCKCHIP_PCIE_AT_SIZE_ALIGN,
 };
 
 static const struct pci_epc_features*
diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
index 15ee949f2485..02368ce9bd54 100644
--- a/drivers/pci/controller/pcie-rockchip.h
+++ b/drivers/pci/controller/pcie-rockchip.h
@@ -248,6 +248,7 @@
 
 #define ROCKCHIP_PCIE_AT_MIN_NUM_BITS  8
 #define ROCKCHIP_PCIE_AT_MAX_NUM_BITS  20
+#define ROCKCHIP_PCIE_AT_SIZE_ALIGN    (1UL << ROCKCHIP_PCIE_AT_MIN_NUM_BITS)
 
 #define ROCKCHIP_PCIE_AT_IB_EP_FUNC_BAR_ADDR0(fn, bar) \
 	(PCIE_CORE_AXI_CONF_BASE + 0x0828 + (fn) * 0x0040 + (bar) * 0x0008)
-- 
2.44.0

[PATCH v2 09/18] PCI: rockchip-ep: Improve rockchip_pcie_ep_unmap_addr()

[Damien Le Moal]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

There is no need to loop over all regions to find the memory window used
to map an address. We can use rockchip_ob_region() to determine the
region index, together with a check that the address passed as argument
is the address used to create the mapping. Furthermore, the
ob_region_map bitmap should also be checked to ensure that we are not
attempting to unmap an address that is not mapped.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index f8c26606df58..93c2466d6fef 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -258,13 +258,9 @@ static void rockchip_pcie_ep_unmap_addr(struct pci_epc *epc, u8 fn, u8 vfn,
 {
 	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
 	struct rockchip_pcie *rockchip = &ep->rockchip;
-	u32 r;
-
-	for (r = 0; r < ep->max_regions; r++)
-		if (ep->ob_addr[r] == addr)
-			break;
+	u32 r = rockchip_ob_region(addr);
 
-	if (r == ep->max_regions)
+	if (addr != ep->ob_addr[r] || !test_bit(r, &ep->ob_region_map))
 		return;
 
 	rockchip_pcie_clear_ep_ob_atu(rockchip, r);
-- 
2.44.0

[PATCH v2 10/18] PCI: rockchip-ep: Improve rockchip_pcie_ep_map_addr()

[Damien Le Moal]

Add a check to verify that the outbound region to be used for mapping an
address is not already in use.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index 93c2466d6fef..36692e34ca31 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -245,6 +245,9 @@ static int rockchip_pcie_ep_map_addr(struct pci_epc *epc, u8 fn, u8 vfn,
 	struct rockchip_pcie *pcie = &ep->rockchip;
 	u32 r = rockchip_ob_region(addr);
 
+	if (test_bit(r, &ep->ob_region_map))
+		return -EBUSY;
+
 	rockchip_pcie_prog_ep_ob_atu(pcie, fn, r, addr, pci_addr, size);
 
 	set_bit(r, &ep->ob_region_map);
-- 
2.44.0

[PATCH v2 11/18] PCI: rockchip-ep: Implement the map_align endpoint controller operation

[Damien Le Moal]

The rockchip PCIe endpoint controller handles PCIe transfers addresses
by masking the lower bits of the programmed PCI address and using the
same number of lower bits from the CPU address space used for the
mapping. For a PCI mapping of size bytes starting from pci_addr, the
number of bits masked is the number of address bits changing in the
address range [pci_addr..pci_addr + size - 1], up to 20 bits, that is,
up to 1MB mappings.

This means that when preparing a PCI address mapping, an endpoint
function driver must use an offset into the allocated controller
memory region that is equal to the mask of the starting PCI address
over rockchip_pcie_ep_ob_atu_num_bits() bits. This offset also
determines the maximum size of the mapping given the starting PCI
address and the fixed 1MB controller memory window size.

Implement the ->map_align() endpoint controller operation to allow the
mapping alignment to be transparently handled by endpoint function
drivers through the function pci_epc_map_align().

This commit contains contributions from Rick Wertenbroek
<rick.wertenbroek@gmail.com>.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 22 ++++++++++++++++++++++
 drivers/pci/controller/pcie-rockchip.h    |  5 +++++
 2 files changed, 27 insertions(+)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index 36692e34ca31..10fff395a13f 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -237,6 +237,27 @@ static inline u32 rockchip_ob_region(phys_addr_t addr)
 	return (addr >> ilog2(SZ_1M)) & 0x1f;
 }
 
+static int rockchip_pcie_ep_map_align(struct pci_epc *epc, u8 fn, u8 vfn,
+				      struct pci_epc_map *map)
+{
+	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
+	int num_bits;
+
+	num_bits = rockchip_pcie_ep_ob_atu_num_bits(&ep->rockchip,
+						map->pci_addr, map->pci_size);
+
+	map->map_pci_addr = map->pci_addr & ~((1ULL << num_bits) - 1);
+	map->map_ofst = map->pci_addr - map->map_pci_addr;
+
+	if (map->map_ofst + map->pci_size > SZ_1M)
+		map->pci_size = SZ_1M - map->map_ofst;
+
+	map->map_size = ALIGN(map->map_ofst + map->pci_size,
+			      ROCKCHIP_PCIE_AT_SIZE_ALIGN);
+
+	return 0;
+}
+
 static int rockchip_pcie_ep_map_addr(struct pci_epc *epc, u8 fn, u8 vfn,
 				     phys_addr_t addr, u64 pci_addr,
 				     size_t size)
@@ -460,6 +481,7 @@ static const struct pci_epc_ops rockchip_pcie_epc_ops = {
 	.write_header	= rockchip_pcie_ep_write_header,
 	.set_bar	= rockchip_pcie_ep_set_bar,
 	.clear_bar	= rockchip_pcie_ep_clear_bar,
+	.map_align	= rockchip_pcie_ep_map_align,
 	.map_addr	= rockchip_pcie_ep_map_addr,
 	.unmap_addr	= rockchip_pcie_ep_unmap_addr,
 	.set_msi	= rockchip_pcie_ep_set_msi,
diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
index 02368ce9bd54..30398156095f 100644
--- a/drivers/pci/controller/pcie-rockchip.h
+++ b/drivers/pci/controller/pcie-rockchip.h
@@ -241,6 +241,11 @@
 #define   ROCKCHIP_PCIE_EP_MSIX_CAP_CP_MASK		GENMASK(15, 8)
 #define ROCKCHIP_PCIE_EP_DUMMY_IRQ_ADDR				0x1
 #define ROCKCHIP_PCIE_EP_PCI_LEGACY_IRQ_ADDR		0x3
+
+#define ROCKCHIP_PCIE_AT_MIN_NUM_BITS	8
+#define ROCKCHIP_PCIE_AT_MAX_NUM_BITS	20
+#define ROCKCHIP_PCIE_AT_SIZE_ALIGN	(1UL << ROCKCHIP_PCIE_AT_MIN_NUM_BITS)
+
 #define ROCKCHIP_PCIE_EP_FUNC_BASE(fn) \
 	(PCIE_EP_PF_CONFIG_REGS_BASE + (((fn) << 12) & GENMASK(19, 12)))
 #define ROCKCHIP_PCIE_EP_VIRT_FUNC_BASE(fn) \
-- 
2.44.0

[PATCH v2 12/18] PCI: rockchip-ep: Refactor rockchip_pcie_ep_probe() memory allocations

[Damien Le Moal]

Introduce the function rockchip_pcie_ep_get_resources() to parse the DT
node of a rockchip PCIe endpoint controller and allocate the outbound
memory region and memory needed for IRQ handling. This function tidies
up rockchip_pcie_ep_probe(). No functional change.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 109 ++++++++++++----------
 1 file changed, 62 insertions(+), 47 deletions(-)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index 10fff395a13f..17d9fe48c621 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -526,15 +526,70 @@ static const struct of_device_id rockchip_pcie_ep_of_match[] = {
 	{},
 };
 
+static int rockchip_pcie_ep_get_resources(struct rockchip_pcie_ep *ep)
+{
+	struct rockchip_pcie *rockchip = &ep->rockchip;
+	struct device *dev = rockchip->dev;
+	struct pci_epc_mem_window *windows = NULL;
+	int err, i;
+
+	err = rockchip_pcie_parse_ep_dt(rockchip, ep);
+	if (err)
+		return err;
+
+	ep->ob_addr = devm_kcalloc(dev, ep->max_regions, sizeof(*ep->ob_addr),
+				   GFP_KERNEL);
+
+	if (!ep->ob_addr)
+		return -ENOMEM;
+
+	windows = devm_kcalloc(dev, ep->max_regions,
+			       sizeof(struct pci_epc_mem_window), GFP_KERNEL);
+	if (!windows)
+		return -ENOMEM;
+
+	for (i = 0; i < ep->max_regions; i++) {
+		windows[i].phys_base = rockchip->mem_res->start + (SZ_1M * i);
+		windows[i].size = SZ_1M;
+		windows[i].page_size = SZ_1M;
+	}
+	err = pci_epc_multi_mem_init(ep->epc, windows, ep->max_regions);
+	devm_kfree(dev, windows);
+
+	if (err < 0) {
+		dev_err(dev, "failed to initialize the memory space\n");
+		return err;
+	}
+
+	ep->irq_cpu_addr = pci_epc_mem_alloc_addr(ep->epc, &ep->irq_phys_addr,
+						  SZ_1M);
+	if (!ep->irq_cpu_addr) {
+		dev_err(dev, "failed to reserve memory space for MSI\n");
+		goto err_epc_mem_exit;
+	}
+
+	ep->irq_pci_addr = ROCKCHIP_PCIE_EP_DUMMY_IRQ_ADDR;
+
+	return 0;
+
+err_epc_mem_exit:
+	pci_epc_mem_exit(ep->epc);
+
+	return err;
+}
+
+static void rockchip_pcie_ep_release_resources(struct rockchip_pcie_ep *ep)
+{
+	pci_epc_mem_exit(ep->epc);
+}
+
 static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct rockchip_pcie_ep *ep;
 	struct rockchip_pcie *rockchip;
 	struct pci_epc *epc;
-	size_t max_regions;
-	struct pci_epc_mem_window *windows = NULL;
-	int err, i;
+	int err;
 	u32 cfg_msi, cfg_msix_cp;
 
 	ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
@@ -554,13 +609,13 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 	ep->epc = epc;
 	epc_set_drvdata(epc, ep);
 
-	err = rockchip_pcie_parse_ep_dt(rockchip, ep);
+	err = rockchip_pcie_ep_get_resources(ep);
 	if (err)
 		return err;
 
 	err = rockchip_pcie_enable_clocks(rockchip);
 	if (err)
-		return err;
+		goto err_release_resources;
 
 	err = rockchip_pcie_init_port(rockchip);
 	if (err)
@@ -570,47 +625,9 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 	rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE,
 			    PCIE_CLIENT_CONFIG);
 
-	max_regions = ep->max_regions;
-	ep->ob_addr = devm_kcalloc(dev, max_regions, sizeof(*ep->ob_addr),
-				   GFP_KERNEL);
-
-	if (!ep->ob_addr) {
-		err = -ENOMEM;
-		goto err_uninit_port;
-	}
-
 	/* Only enable function 0 by default */
 	rockchip_pcie_write(rockchip, BIT(0), PCIE_CORE_PHY_FUNC_CFG);
 
-	windows = devm_kcalloc(dev, ep->max_regions,
-			       sizeof(struct pci_epc_mem_window), GFP_KERNEL);
-	if (!windows) {
-		err = -ENOMEM;
-		goto err_uninit_port;
-	}
-	for (i = 0; i < ep->max_regions; i++) {
-		windows[i].phys_base = rockchip->mem_res->start + (SZ_1M * i);
-		windows[i].size = SZ_1M;
-		windows[i].page_size = SZ_1M;
-	}
-	err = pci_epc_multi_mem_init(epc, windows, ep->max_regions);
-	devm_kfree(dev, windows);
-
-	if (err < 0) {
-		dev_err(dev, "failed to initialize the memory space\n");
-		goto err_uninit_port;
-	}
-
-	ep->irq_cpu_addr = pci_epc_mem_alloc_addr(epc, &ep->irq_phys_addr,
-						  SZ_1M);
-	if (!ep->irq_cpu_addr) {
-		dev_err(dev, "failed to reserve memory space for MSI\n");
-		err = -ENOMEM;
-		goto err_epc_mem_exit;
-	}
-
-	ep->irq_pci_addr = ROCKCHIP_PCIE_EP_DUMMY_IRQ_ADDR;
-
 	/*
 	 * MSI-X is not supported but the controller still advertises the MSI-X
 	 * capability by default, which can lead to the Root Complex side
@@ -638,10 +655,8 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 			    PCIE_CLIENT_CONFIG);
 
 	return 0;
-err_epc_mem_exit:
-	pci_epc_mem_exit(epc);
-err_uninit_port:
-	rockchip_pcie_deinit_phys(rockchip);
+err_release_resources:
+	rockchip_pcie_ep_release_resources(ep);
 err_disable_clocks:
 	rockchip_pcie_disable_clocks(rockchip);
 	return err;
-- 
2.44.0

[PATCH v2 13/18] PCI: rockchip-ep: Refactor rockchip_pcie_ep_probe() MSI-X hiding

[Damien Le Moal]

Move the code in rockchip_pcie_ep_probe() to hide the MSI-X capability
to its own function, rockchip_pcie_ep_hide_msix_cap(). No functional
changes.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 54 +++++++++++++----------
 1 file changed, 30 insertions(+), 24 deletions(-)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index 17d9fe48c621..a7d008d95a8a 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -583,6 +583,34 @@ static void rockchip_pcie_ep_release_resources(struct rockchip_pcie_ep *ep)
 	pci_epc_mem_exit(ep->epc);
 }
 
+static void rockchip_pcie_ep_hide_msix_cap(struct rockchip_pcie *rockchip)
+{
+	u32 cfg_msi, cfg_msix_cp;
+
+	/*
+	 * MSI-X is not supported but the controller still advertises the MSI-X
+	 * capability by default, which can lead to the Root Complex side
+	 * allocating MSI-X vectors which cannot be used. Avoid this by skipping
+	 * the MSI-X capability entry in the PCIe capabilities linked-list: get
+	 * the next pointer from the MSI-X entry and set that in the MSI
+	 * capability entry (which is the previous entry). This way the MSI-X
+	 * entry is skipped (left out of the linked-list) and not advertised.
+	 */
+	cfg_msi = rockchip_pcie_read(rockchip, PCIE_EP_CONFIG_BASE +
+				     ROCKCHIP_PCIE_EP_MSI_CTRL_REG);
+
+	cfg_msi &= ~ROCKCHIP_PCIE_EP_MSI_CP1_MASK;
+
+	cfg_msix_cp = rockchip_pcie_read(rockchip, PCIE_EP_CONFIG_BASE +
+					 ROCKCHIP_PCIE_EP_MSIX_CAP_REG) &
+					 ROCKCHIP_PCIE_EP_MSIX_CAP_CP_MASK;
+
+	cfg_msi |= cfg_msix_cp;
+
+	rockchip_pcie_write(rockchip, cfg_msi,
+			    PCIE_EP_CONFIG_BASE + ROCKCHIP_PCIE_EP_MSI_CTRL_REG);
+}
+
 static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -590,7 +618,6 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 	struct rockchip_pcie *rockchip;
 	struct pci_epc *epc;
 	int err;
-	u32 cfg_msi, cfg_msix_cp;
 
 	ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
 	if (!ep)
@@ -621,6 +648,8 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 	if (err)
 		goto err_disable_clocks;
 
+	rockchip_pcie_ep_hide_msix_cap(rockchip);
+
 	/* Establish the link automatically */
 	rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE,
 			    PCIE_CLIENT_CONFIG);
@@ -628,29 +657,6 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 	/* Only enable function 0 by default */
 	rockchip_pcie_write(rockchip, BIT(0), PCIE_CORE_PHY_FUNC_CFG);
 
-	/*
-	 * MSI-X is not supported but the controller still advertises the MSI-X
-	 * capability by default, which can lead to the Root Complex side
-	 * allocating MSI-X vectors which cannot be used. Avoid this by skipping
-	 * the MSI-X capability entry in the PCIe capabilities linked-list: get
-	 * the next pointer from the MSI-X entry and set that in the MSI
-	 * capability entry (which is the previous entry). This way the MSI-X
-	 * entry is skipped (left out of the linked-list) and not advertised.
-	 */
-	cfg_msi = rockchip_pcie_read(rockchip, PCIE_EP_CONFIG_BASE +
-				     ROCKCHIP_PCIE_EP_MSI_CTRL_REG);
-
-	cfg_msi &= ~ROCKCHIP_PCIE_EP_MSI_CP1_MASK;
-
-	cfg_msix_cp = rockchip_pcie_read(rockchip, PCIE_EP_CONFIG_BASE +
-					 ROCKCHIP_PCIE_EP_MSIX_CAP_REG) &
-					 ROCKCHIP_PCIE_EP_MSIX_CAP_CP_MASK;
-
-	cfg_msi |= cfg_msix_cp;
-
-	rockchip_pcie_write(rockchip, cfg_msi,
-			    PCIE_EP_CONFIG_BASE + ROCKCHIP_PCIE_EP_MSI_CTRL_REG);
-
 	rockchip_pcie_write(rockchip, PCIE_CLIENT_CONF_ENABLE,
 			    PCIE_CLIENT_CONFIG);
 
-- 
2.44.0

[PATCH v2 14/18] PCI: rockchip-ep: Refactor endpoint link training enable

[Damien Le Moal]

The function rockchip_pcie_init_port() enables link training for a
controller configured in EP mode. Enabling link training is again done
in rockchip_pcie_ep_probe() after that function executed
rockchip_pcie_init_port(). Enabling link training only needs to be done
once, and doing so at the probe stage before the controller is actually
started by the user serves no purpose.

Refactor this by removing the link training enablement from both
rockchip_pcie_init_port() and rockchip_pcie_ep_probe() and moving it to
the endpoint start operation defined with rockchip_pcie_ep_start().
Enabling the controller configuration using the PCIE_CLIENT_CONF_ENABLE
bit in the same PCIE_CLIENT_CONFIG register is also move to
rockchip_pcie_ep_start() and both the controller configuration and link
training enable bits are set with a single call to
rockchip_pcie_write().

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 14 ++++++--------
 drivers/pci/controller/pcie-rockchip.c    |  5 +++--
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index a7d008d95a8a..9215cac91f61 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -461,6 +461,12 @@ static int rockchip_pcie_ep_start(struct pci_epc *epc)
 
 	rockchip_pcie_write(rockchip, cfg, PCIE_CORE_PHY_FUNC_CFG);
 
+	/* Enable configuration and start link training */
+	rockchip_pcie_write(rockchip,
+			    PCIE_CLIENT_LINK_TRAIN_ENABLE |
+			    PCIE_CLIENT_CONF_ENABLE,
+			    PCIE_CLIENT_CONFIG);
+
 	return 0;
 }
 
@@ -539,7 +545,6 @@ static int rockchip_pcie_ep_get_resources(struct rockchip_pcie_ep *ep)
 
 	ep->ob_addr = devm_kcalloc(dev, ep->max_regions, sizeof(*ep->ob_addr),
 				   GFP_KERNEL);
-
 	if (!ep->ob_addr)
 		return -ENOMEM;
 
@@ -650,16 +655,9 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 
 	rockchip_pcie_ep_hide_msix_cap(rockchip);
 
-	/* Establish the link automatically */
-	rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE,
-			    PCIE_CLIENT_CONFIG);
-
 	/* Only enable function 0 by default */
 	rockchip_pcie_write(rockchip, BIT(0), PCIE_CORE_PHY_FUNC_CFG);
 
-	rockchip_pcie_write(rockchip, PCIE_CLIENT_CONF_ENABLE,
-			    PCIE_CLIENT_CONFIG);
-
 	return 0;
 err_release_resources:
 	rockchip_pcie_ep_release_resources(ep);
diff --git a/drivers/pci/controller/pcie-rockchip.c b/drivers/pci/controller/pcie-rockchip.c
index 0ef2e622d36e..dbec700ba9f9 100644
--- a/drivers/pci/controller/pcie-rockchip.c
+++ b/drivers/pci/controller/pcie-rockchip.c
@@ -244,11 +244,12 @@ int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
 		rockchip_pcie_write(rockchip, PCIE_CLIENT_GEN_SEL_1,
 				    PCIE_CLIENT_CONFIG);
 
-	regs = PCIE_CLIENT_LINK_TRAIN_ENABLE | PCIE_CLIENT_ARI_ENABLE |
+	regs = PCIE_CLIENT_ARI_ENABLE |
 	       PCIE_CLIENT_CONF_LANE_NUM(rockchip->lanes);
 
 	if (rockchip->is_rc)
-		regs |= PCIE_CLIENT_CONF_ENABLE | PCIE_CLIENT_MODE_RC;
+		regs |= PCIE_CLIENT_LINK_TRAIN_ENABLE |
+			PCIE_CLIENT_CONF_ENABLE | PCIE_CLIENT_MODE_RC;
 	else
 		regs |= PCIE_CLIENT_CONF_DISABLE | PCIE_CLIENT_MODE_EP;
 
-- 
2.44.0

[PATCH v2 15/18] PCI: rockship-ep: Introduce rockchip_pcie_ep_stop()

[Damien Le Moal]

Define the EPC operation ->stop for the rockchip endpoint driver with
the function rockchip_pcie_ep_stop(). This function disables link
training and the controller configuration, as the reverse to what
the start operation defined with rockchip_pcie_ep_start() does.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 13 +++++++++++++
 drivers/pci/controller/pcie-rockchip.h    |  1 +
 2 files changed, 14 insertions(+)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index 9215cac91f61..2767e8f1771d 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -470,6 +470,18 @@ static int rockchip_pcie_ep_start(struct pci_epc *epc)
 	return 0;
 }
 
+static void rockchip_pcie_ep_stop(struct pci_epc *epc)
+{
+	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
+	struct rockchip_pcie *rockchip = &ep->rockchip;
+
+	/* Stop link training and disable configuration */
+	rockchip_pcie_write(rockchip,
+			    PCIE_CLIENT_CONF_DISABLE |
+			    PCIE_CLIENT_LINK_TRAIN_DISABLE,
+			    PCIE_CLIENT_CONFIG);
+}
+
 static const struct pci_epc_features rockchip_pcie_epc_features = {
 	.linkup_notifier = false,
 	.msi_capable = true,
@@ -494,6 +506,7 @@ static const struct pci_epc_ops rockchip_pcie_epc_ops = {
 	.get_msi	= rockchip_pcie_ep_get_msi,
 	.raise_irq	= rockchip_pcie_ep_raise_irq,
 	.start		= rockchip_pcie_ep_start,
+	.stop		= rockchip_pcie_ep_stop,
 	.get_features	= rockchip_pcie_ep_get_features,
 };
 
diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
index 30398156095f..0263f158ee8d 100644
--- a/drivers/pci/controller/pcie-rockchip.h
+++ b/drivers/pci/controller/pcie-rockchip.h
@@ -32,6 +32,7 @@
 #define   PCIE_CLIENT_CONF_ENABLE	  HIWORD_UPDATE_BIT(0x0001)
 #define   PCIE_CLIENT_CONF_DISABLE       HIWORD_UPDATE(0x0001, 0)
 #define   PCIE_CLIENT_LINK_TRAIN_ENABLE	  HIWORD_UPDATE_BIT(0x0002)
+#define   PCIE_CLIENT_LINK_TRAIN_DISABLE  HIWORD_UPDATE(0x0002, 0)
 #define   PCIE_CLIENT_ARI_ENABLE	  HIWORD_UPDATE_BIT(0x0008)
 #define   PCIE_CLIENT_CONF_LANE_NUM(x)	  HIWORD_UPDATE(0x0030, ENCODE_LANES(x))
 #define   PCIE_CLIENT_MODE_RC		  HIWORD_UPDATE_BIT(0x0040)
-- 
2.44.0

[PATCH v2 16/18] PCI: rockchip-ep: Improve link training

[Damien Le Moal]

The Rockchip rk339 technical reference manual describe the endpoint mode
link training process clearly and states that:
  Insure link training completion and success by observing link_st field
  in PCIe Client BASIC_STATUS1 register change to 2'b11. If both side
  support PCIe Gen2 speed, re-train can be Initiated by asserting the
  Retrain Link field in Link Control and Status Register. The software
  should insure the BASIC_STATUS0[negotiated_speed] changes to "1", that
  indicates re-train to Gen2 successfully.
This procedure is very similar to what is done for the root-port mode in
rockchip_pcie_host_init_port().

Implement this link training procedure for the endpoint mode as well.
Given that the rk3399 SoC does not have an interrupt signaling link
status changes, training is implemented as a delayed work which is
rescheduled until the link training completes or the endpoint controller
is stopped. The link training work is first scheduled in
rockchip_pcie_ep_start() when the endpoint function is started. Link
training completion is signaled to the function using pci_epc_linkup().
Accordingly, the linkup_notifier field of the rockchip pci_epc_features
structure is changed to true.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 79 ++++++++++++++++++++++-
 drivers/pci/controller/pcie-rockchip.h    | 11 ++++
 2 files changed, 89 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index 2767e8f1771d..4006e7dee71a 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -16,6 +16,8 @@
 #include <linux/platform_device.h>
 #include <linux/pci-epf.h>
 #include <linux/sizes.h>
+#include <linux/workqueue.h>
+#include <linux/iopoll.h>
 
 #include "pcie-rockchip.h"
 
@@ -48,6 +50,7 @@ struct rockchip_pcie_ep {
 	u64			irq_pci_addr;
 	u8			irq_pci_fn;
 	u8			irq_pending;
+	struct delayed_work	link_training;
 };
 
 static void rockchip_pcie_clear_ep_ob_atu(struct rockchip_pcie *rockchip,
@@ -467,6 +470,8 @@ static int rockchip_pcie_ep_start(struct pci_epc *epc)
 			    PCIE_CLIENT_CONF_ENABLE,
 			    PCIE_CLIENT_CONFIG);
 
+	schedule_delayed_work(&ep->link_training, 0);
+
 	return 0;
 }
 
@@ -475,6 +480,8 @@ static void rockchip_pcie_ep_stop(struct pci_epc *epc)
 	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
 	struct rockchip_pcie *rockchip = &ep->rockchip;
 
+	cancel_delayed_work_sync(&ep->link_training);
+
 	/* Stop link training and disable configuration */
 	rockchip_pcie_write(rockchip,
 			    PCIE_CLIENT_CONF_DISABLE |
@@ -482,8 +489,77 @@ static void rockchip_pcie_ep_stop(struct pci_epc *epc)
 			    PCIE_CLIENT_CONFIG);
 }
 
+static void rockchip_pcie_ep_retrain_link(struct rockchip_pcie *rockchip)
+{
+	u32 status;
+
+	status = rockchip_pcie_read(rockchip, PCIE_EP_CONFIG_LCS);
+	status |= PCI_EXP_LNKCTL_RL;
+	rockchip_pcie_write(rockchip, status, PCIE_EP_CONFIG_LCS);
+}
+
+static bool rockchip_pcie_ep_link_up(struct rockchip_pcie *rockchip)
+{
+	u32 val = rockchip_pcie_read(rockchip, PCIE_CLIENT_BASIC_STATUS1);
+
+	return PCIE_LINK_UP(val);
+}
+
+static void rockchip_pcie_ep_link_training(struct work_struct *work)
+{
+	struct rockchip_pcie_ep *ep =
+		container_of(work, struct rockchip_pcie_ep, link_training.work);
+	struct rockchip_pcie *rockchip = &ep->rockchip;
+	struct device *dev = rockchip->dev;
+	u32 val;
+	int ret;
+
+	/* Enable Gen1 training and wait for its completion */
+	ret = readl_poll_timeout(rockchip->apb_base + PCIE_CORE_CTRL,
+				 val, PCIE_LINK_TRAINING_DONE(val), 50,
+				 LINK_TRAIN_TIMEOUT);
+	if (ret)
+		goto again;
+
+	/* Make sure that the link is up */
+	ret = readl_poll_timeout(rockchip->apb_base + PCIE_CLIENT_BASIC_STATUS1,
+				 val, PCIE_LINK_UP(val), 50,
+				 LINK_TRAIN_TIMEOUT);
+	if (ret)
+		goto again;
+
+	/* Check the current speed */
+	val = rockchip_pcie_read(rockchip, PCIE_CORE_CTRL);
+	if (!PCIE_LINK_IS_GEN2(val) && rockchip->link_gen == 2) {
+		/* Enable retrain for gen2 */
+		rockchip_pcie_ep_retrain_link(rockchip);
+		readl_poll_timeout(rockchip->apb_base + PCIE_CORE_CTRL,
+				   val, PCIE_LINK_IS_GEN2(val), 50,
+				   LINK_TRAIN_TIMEOUT);
+	}
+
+	/* Check again that the link is up */
+	if (!rockchip_pcie_ep_link_up(rockchip))
+		goto again;
+
+	val = rockchip_pcie_read(rockchip, PCIE_CLIENT_BASIC_STATUS0);
+	dev_info(dev,
+		 "Link UP (Negociated speed: %sGT/s, width: x%lu)\n",
+		 (val & PCIE_CLIENT_NEG_LINK_SPEED) ? "5" : "2.5",
+		 ((val & PCIE_CLIENT_NEG_LINK_WIDTH_MASK) >>
+		  PCIE_CLIENT_NEG_LINK_WIDTH_SHIFT) << 1);
+
+	/* Notify the function */
+	pci_epc_linkup(ep->epc);
+
+	return;
+
+again:
+	schedule_delayed_work(&ep->link_training, msecs_to_jiffies(5));
+}
+
 static const struct pci_epc_features rockchip_pcie_epc_features = {
-	.linkup_notifier = false,
+	.linkup_notifier = true,
 	.msi_capable = true,
 	.msix_capable = false,
 	.align = ROCKCHIP_PCIE_AT_SIZE_ALIGN,
@@ -644,6 +720,7 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 	rockchip = &ep->rockchip;
 	rockchip->is_rc = false;
 	rockchip->dev = dev;
+	INIT_DELAYED_WORK(&ep->link_training, rockchip_pcie_ep_link_training);
 
 	epc = devm_pci_epc_create(dev, &rockchip_pcie_epc_ops);
 	if (IS_ERR(epc)) {
diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
index 0263f158ee8d..3963b7097a91 100644
--- a/drivers/pci/controller/pcie-rockchip.h
+++ b/drivers/pci/controller/pcie-rockchip.h
@@ -26,6 +26,7 @@
 #define MAX_LANE_NUM			4
 #define MAX_REGION_LIMIT		32
 #define MIN_EP_APERTURE			28
+#define LINK_TRAIN_TIMEOUT		(5000 * USEC_PER_MSEC)
 
 #define PCIE_CLIENT_BASE		0x0
 #define PCIE_CLIENT_CONFIG		(PCIE_CLIENT_BASE + 0x00)
@@ -50,6 +51,10 @@
 #define   PCIE_CLIENT_DEBUG_LTSSM_MASK		GENMASK(5, 0)
 #define   PCIE_CLIENT_DEBUG_LTSSM_L1		0x18
 #define   PCIE_CLIENT_DEBUG_LTSSM_L2		0x19
+#define PCIE_CLIENT_BASIC_STATUS0	(PCIE_CLIENT_BASE + 0x44)
+#define   PCIE_CLIENT_NEG_LINK_WIDTH_MASK	GENMASK(7, 6)
+#define   PCIE_CLIENT_NEG_LINK_WIDTH_SHIFT	6
+#define   PCIE_CLIENT_NEG_LINK_SPEED		BIT(5)
 #define PCIE_CLIENT_BASIC_STATUS1	(PCIE_CLIENT_BASE + 0x48)
 #define   PCIE_CLIENT_LINK_STATUS_UP		0x00300000
 #define   PCIE_CLIENT_LINK_STATUS_MASK		0x00300000
@@ -87,6 +92,8 @@
 
 #define PCIE_CORE_CTRL_MGMT_BASE	0x900000
 #define PCIE_CORE_CTRL			(PCIE_CORE_CTRL_MGMT_BASE + 0x000)
+#define   PCIE_CORE_PL_CONF_LS_MASK		0x00000001
+#define   PCIE_CORE_PL_CONF_LS_READY		0x00000001
 #define   PCIE_CORE_PL_CONF_SPEED_5G		0x00000008
 #define   PCIE_CORE_PL_CONF_SPEED_MASK		0x00000018
 #define   PCIE_CORE_PL_CONF_LANE_MASK		0x00000006
@@ -144,6 +151,7 @@
 #define PCIE_RC_CONFIG_BASE		0xa00000
 #define PCIE_EP_CONFIG_BASE		0xa00000
 #define PCIE_EP_CONFIG_DID_VID		(PCIE_EP_CONFIG_BASE + 0x00)
+#define PCIE_EP_CONFIG_LCS		(PCIE_EP_CONFIG_BASE + 0xd0)
 #define PCIE_RC_CONFIG_RID_CCR		(PCIE_RC_CONFIG_BASE + 0x08)
 #define PCIE_RC_CONFIG_DCR		(PCIE_RC_CONFIG_BASE + 0xc4)
 #define   PCIE_RC_CONFIG_DCR_CSPL_SHIFT		18
@@ -155,6 +163,7 @@
 #define PCIE_RC_CONFIG_LINK_CAP		(PCIE_RC_CONFIG_BASE + 0xcc)
 #define   PCIE_RC_CONFIG_LINK_CAP_L0S		BIT(10)
 #define PCIE_RC_CONFIG_LCS		(PCIE_RC_CONFIG_BASE + 0xd0)
+#define PCIE_EP_CONFIG_LCS		(PCIE_EP_CONFIG_BASE + 0xd0)
 #define PCIE_RC_CONFIG_L1_SUBSTATE_CTRL2 (PCIE_RC_CONFIG_BASE + 0x90c)
 #define PCIE_RC_CONFIG_THP_CAP		(PCIE_RC_CONFIG_BASE + 0x274)
 #define   PCIE_RC_CONFIG_THP_CAP_NEXT_MASK	GENMASK(31, 20)
@@ -192,6 +201,8 @@
 #define ROCKCHIP_VENDOR_ID			0x1d87
 #define PCIE_LINK_IS_L2(x) \
 	(((x) & PCIE_CLIENT_DEBUG_LTSSM_MASK) == PCIE_CLIENT_DEBUG_LTSSM_L2)
+#define PCIE_LINK_TRAINING_DONE(x) \
+	(((x) & PCIE_CORE_PL_CONF_LS_MASK) == PCIE_CORE_PL_CONF_LS_READY)
 #define PCIE_LINK_UP(x) \
 	(((x) & PCIE_CLIENT_LINK_STATUS_MASK) == PCIE_CLIENT_LINK_STATUS_UP)
 #define PCIE_LINK_IS_GEN2(x) \
-- 
2.44.0

[PATCH v2 17/18] dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

[Damien Le Moal]

From: Wilfred Mallawa <wilfred.mallawa@wdc.com>

Describe the `ep-gpios` property which is used to map the PERST# input
signal for endpoint mode.

Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 .../devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml       | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
index 6b62f6f58efe..9331d44d6963 100644
--- a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
+++ b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
@@ -30,6 +30,9 @@ properties:
     maximum: 32
     default: 32
 
+  ep-gpios:
+    description: Input GPIO configured for the PERST# signal.
+
 required:
   - rockchip,max-outbound-regions
 
-- 
2.44.0

[PATCH v2 18/18] PCI: rockchip-ep: Handle PERST# signal in endpoint mode

[Damien Le Moal]

Currently, the Rockchip PCIe endpoint controller driver does not handle
PERST# signal, which prevents detecting when link training should
actually be started or if the host reset the device. This however can
be supported using the controller ep_gpio, set as an input GPIO for
endpoint mode.

Modify the endpoint rockchip driver to get the ep_gpio and its
associated interrupt which is serviced using a threaded IRQ with the
function rockchip_pcie_ep_perst_irq_thread() as handler.

This handler function notifies a link down event corresponding to the RC
side asserting the PERST# signal using pci_epc_linkdown() when the gpio
is high. Once the gpio value goes down, corresponding to the RC
de-asserting the PERST# signal, link training is started. The polarity
of the gpio interrupt trigger is changed from high to low after the RC
asserted PERST#, and conversely changed from low to high after the RC
de-asserts PERST#.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/pci/controller/pcie-rockchip-ep.c | 118 +++++++++++++++++++++-
 drivers/pci/controller/pcie-rockchip.c    |  12 +--
 2 files changed, 122 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
index 4006e7dee71a..e098c5fb6d59 100644
--- a/drivers/pci/controller/pcie-rockchip-ep.c
+++ b/drivers/pci/controller/pcie-rockchip-ep.c
@@ -18,6 +18,7 @@
 #include <linux/sizes.h>
 #include <linux/workqueue.h>
 #include <linux/iopoll.h>
+#include <linux/gpio/consumer.h>
 
 #include "pcie-rockchip.h"
 
@@ -50,6 +51,9 @@ struct rockchip_pcie_ep {
 	u64			irq_pci_addr;
 	u8			irq_pci_fn;
 	u8			irq_pending;
+	int			perst_irq;
+	bool			perst_asserted;
+	bool			link_up;
 	struct delayed_work	link_training;
 };
 
@@ -464,13 +468,17 @@ static int rockchip_pcie_ep_start(struct pci_epc *epc)
 
 	rockchip_pcie_write(rockchip, cfg, PCIE_CORE_PHY_FUNC_CFG);
 
+	if (rockchip->ep_gpio)
+		enable_irq(ep->perst_irq);
+
 	/* Enable configuration and start link training */
 	rockchip_pcie_write(rockchip,
 			    PCIE_CLIENT_LINK_TRAIN_ENABLE |
 			    PCIE_CLIENT_CONF_ENABLE,
 			    PCIE_CLIENT_CONFIG);
 
-	schedule_delayed_work(&ep->link_training, 0);
+	if (!rockchip->ep_gpio)
+		schedule_delayed_work(&ep->link_training, 0);
 
 	return 0;
 }
@@ -480,6 +488,11 @@ static void rockchip_pcie_ep_stop(struct pci_epc *epc)
 	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
 	struct rockchip_pcie *rockchip = &ep->rockchip;
 
+	if (rockchip->ep_gpio) {
+		ep->perst_asserted = true;
+		disable_irq(ep->perst_irq);
+	}
+
 	cancel_delayed_work_sync(&ep->link_training);
 
 	/* Stop link training and disable configuration */
@@ -542,6 +555,13 @@ static void rockchip_pcie_ep_link_training(struct work_struct *work)
 	if (!rockchip_pcie_ep_link_up(rockchip))
 		goto again;
 
+	/*
+	 * If PERST was asserted while polling the link, do not notify
+	 * the function.
+	 */
+	if (ep->perst_asserted)
+		return;
+
 	val = rockchip_pcie_read(rockchip, PCIE_CLIENT_BASIC_STATUS0);
 	dev_info(dev,
 		 "Link UP (Negociated speed: %sGT/s, width: x%lu)\n",
@@ -551,6 +571,7 @@ static void rockchip_pcie_ep_link_training(struct work_struct *work)
 
 	/* Notify the function */
 	pci_epc_linkup(ep->epc);
+	ep->link_up = true;
 
 	return;
 
@@ -558,6 +579,94 @@ static void rockchip_pcie_ep_link_training(struct work_struct *work)
 	schedule_delayed_work(&ep->link_training, msecs_to_jiffies(5));
 }
 
+static void rockchip_pcie_ep_perst_assert(struct rockchip_pcie_ep *ep)
+{
+	struct rockchip_pcie *rockchip = &ep->rockchip;
+	struct device *dev = rockchip->dev;
+
+	dev_dbg(dev, "PERST asserted, link down\n");
+
+	if (ep->perst_asserted)
+		return;
+
+	ep->perst_asserted = true;
+
+	cancel_delayed_work_sync(&ep->link_training);
+
+	if (ep->link_up) {
+		pci_epc_linkdown(ep->epc);
+		ep->link_up = false;
+	}
+}
+
+static void rockchip_pcie_ep_perst_deassert(struct rockchip_pcie_ep *ep)
+{
+	struct rockchip_pcie *rockchip = &ep->rockchip;
+	struct device *dev = rockchip->dev;
+
+	dev_dbg(dev, "PERST de-asserted, starting link training\n");
+
+	if (!ep->perst_asserted)
+		return;
+
+	ep->perst_asserted = false;
+
+	/* Enable link re-training */
+	rockchip_pcie_ep_retrain_link(rockchip);
+
+	/* Start link training */
+	schedule_delayed_work(&ep->link_training, 0);
+}
+
+static irqreturn_t rockchip_pcie_ep_perst_irq_thread(int irq, void *data)
+{
+	struct pci_epc *epc = data;
+	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
+	struct rockchip_pcie *rockchip = &ep->rockchip;
+	u32 perst = gpiod_get_value(rockchip->ep_gpio);
+
+	if (perst)
+		rockchip_pcie_ep_perst_assert(ep);
+	else
+		rockchip_pcie_ep_perst_deassert(ep);
+
+	irq_set_irq_type(ep->perst_irq,
+			 (perst ? IRQF_TRIGGER_HIGH : IRQF_TRIGGER_LOW));
+
+	return IRQ_HANDLED;
+}
+
+static int rockchip_pcie_ep_setup_irq(struct pci_epc *epc)
+{
+	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
+	struct rockchip_pcie *rockchip = &ep->rockchip;
+	struct device *dev = rockchip->dev;
+	int ret;
+
+	if (!rockchip->ep_gpio)
+		return 0;
+
+	/* PCIe reset interrupt */
+	ep->perst_irq = gpiod_to_irq(rockchip->ep_gpio);
+	if (ep->perst_irq < 0) {
+		dev_err(dev, "No corresponding IRQ for PERST GPIO\n");
+		return ep->perst_irq;
+	}
+
+	ep->perst_asserted = true;
+	irq_set_status_flags(ep->perst_irq, IRQ_NOAUTOEN);
+	ret = devm_request_threaded_irq(dev, ep->perst_irq, NULL,
+					rockchip_pcie_ep_perst_irq_thread,
+					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+					"pcie-ep-perst", epc);
+	if (ret) {
+		dev_err(dev, "Request PERST GPIO IRQ failed %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
 static const struct pci_epc_features rockchip_pcie_epc_features = {
 	.linkup_notifier = true,
 	.msi_capable = true,
@@ -721,6 +830,7 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 	rockchip->is_rc = false;
 	rockchip->dev = dev;
 	INIT_DELAYED_WORK(&ep->link_training, rockchip_pcie_ep_link_training);
+	ep->link_up = false;
 
 	epc = devm_pci_epc_create(dev, &rockchip_pcie_epc_ops);
 	if (IS_ERR(epc)) {
@@ -748,7 +858,13 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
 	/* Only enable function 0 by default */
 	rockchip_pcie_write(rockchip, BIT(0), PCIE_CORE_PHY_FUNC_CFG);
 
+	err = rockchip_pcie_ep_setup_irq(epc);
+	if (err < 0)
+		goto err_uninit_port;
+
 	return 0;
+err_uninit_port:
+	rockchip_pcie_deinit_phys(rockchip);
 err_release_resources:
 	rockchip_pcie_ep_release_resources(ep);
 err_disable_clocks:
diff --git a/drivers/pci/controller/pcie-rockchip.c b/drivers/pci/controller/pcie-rockchip.c
index dbec700ba9f9..3938c0b6b5a9 100644
--- a/drivers/pci/controller/pcie-rockchip.c
+++ b/drivers/pci/controller/pcie-rockchip.c
@@ -119,13 +119,11 @@ int rockchip_pcie_parse_dt(struct rockchip_pcie *rockchip)
 		return PTR_ERR(rockchip->aclk_rst);
 	}
 
-	if (rockchip->is_rc) {
-		rockchip->ep_gpio = devm_gpiod_get_optional(dev, "ep",
-							    GPIOD_OUT_HIGH);
-		if (IS_ERR(rockchip->ep_gpio))
-			return dev_err_probe(dev, PTR_ERR(rockchip->ep_gpio),
-					     "failed to get ep GPIO\n");
-	}
+	rockchip->ep_gpio = devm_gpiod_get_optional(dev, "ep",
+				rockchip->is_rc ? GPIOD_OUT_HIGH : GPIOD_IN);
+	if (IS_ERR(rockchip->ep_gpio))
+		return dev_err_probe(dev, PTR_ERR(rockchip->ep_gpio),
+				     "failed to get ep GPIO\n");
 
 	rockchip->aclk_pcie = devm_clk_get(dev, "aclk");
 	if (IS_ERR(rockchip->aclk_pcie)) {
-- 
2.44.0

Re: [PATCH v2 17/18] dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

[Krzysztof Kozlowski]

On 30/03/2024 05:19, Damien Le Moal wrote:
> From: Wilfred Mallawa <wilfred.mallawa@wdc.com>
> 
> Describe the `ep-gpios` property which is used to map the PERST# input
> signal for endpoint mode.
> 
> Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>  .../devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml       | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
> index 6b62f6f58efe..9331d44d6963 100644
> --- a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
> +++ b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
> @@ -30,6 +30,9 @@ properties:
>      maximum: 32
>      default: 32
>  
> +  ep-gpios:
> +    description: Input GPIO configured for the PERST# signal.

Missing maxItems. But more important: why existing property perst-gpios,
which you already have there in common schema, is not correct for this case?

Best regards,
Krzysztof

Re: [PATCH v2 17/18] dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

[Damien Le Moal]

On 3/30/24 18:16, Krzysztof Kozlowski wrote:
> On 30/03/2024 05:19, Damien Le Moal wrote:
>> From: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>
>> Describe the `ep-gpios` property which is used to map the PERST# input
>> signal for endpoint mode.
>>
>> Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
>> ---
>>  .../devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml       | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>> index 6b62f6f58efe..9331d44d6963 100644
>> --- a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>> +++ b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>> @@ -30,6 +30,9 @@ properties:
>>      maximum: 32
>>      default: 32
>>  
>> +  ep-gpios:
>> +    description: Input GPIO configured for the PERST# signal.
> 
> Missing maxItems. But more important: why existing property perst-gpios,
> which you already have there in common schema, is not correct for this case?

I am confused... Where do you find perst-gpios defined for the rk3399 ?
Under Documentation/devicetree/bindings/pci/, the only schema I see using
perst-gpios property are for the qcom (Qualcomm) controllers.
The RC bindings for the rockchip rk3399 PCIe controller
(pci/rockchip,rk3399-pcie.yaml) already define the ep-gpios property. So if
anything, this patch should be probably be modified to move this property to the
common schema in pci/rockchip,rk3399-pcie-common.yaml.
No ?

> 
> Best regards,
> Krzysztof
> 

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 17/18] dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

[Krzysztof Kozlowski]

On 01/04/2024 01:06, Damien Le Moal wrote:
> On 3/30/24 18:16, Krzysztof Kozlowski wrote:
>> On 30/03/2024 05:19, Damien Le Moal wrote:
>>> From: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>
>>> Describe the `ep-gpios` property which is used to map the PERST# input
>>> signal for endpoint mode.
>>>
>>> Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
>>> ---
>>>  .../devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml       | 3 +++
>>>  1 file changed, 3 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>> index 6b62f6f58efe..9331d44d6963 100644
>>> --- a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>> +++ b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>> @@ -30,6 +30,9 @@ properties:
>>>      maximum: 32
>>>      default: 32
>>>  
>>> +  ep-gpios:
>>> +    description: Input GPIO configured for the PERST# signal.
>>
>> Missing maxItems. But more important: why existing property perst-gpios,
>> which you already have there in common schema, is not correct for this case?
> 
> I am confused... Where do you find perst-gpios defined for the rk3399 ?
> Under Documentation/devicetree/bindings/pci/, the only schema I see using
> perst-gpios property are for the qcom (Qualcomm) controllers.

You are right, it's so far only in Qualcomm.

> The RC bindings for the rockchip rk3399 PCIe controller
> (pci/rockchip,rk3399-pcie.yaml) already define the ep-gpios property. So if

Any reason why this cannot be named like GPIO? Is there already a user
of this in Linux kernel? Commit msg says nothing about this, so that's
why I would expect name matching the signal.

Best regards,
Krzysztof

Re: [PATCH v2 17/18] dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

[Damien Le Moal]

On 4/1/24 18:57, Krzysztof Kozlowski wrote:
> On 01/04/2024 01:06, Damien Le Moal wrote:
>> On 3/30/24 18:16, Krzysztof Kozlowski wrote:
>>> On 30/03/2024 05:19, Damien Le Moal wrote:
>>>> From: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>>
>>>> Describe the `ep-gpios` property which is used to map the PERST# input
>>>> signal for endpoint mode.
>>>>
>>>> Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
>>>> ---
>>>>  .../devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml       | 3 +++
>>>>  1 file changed, 3 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>> index 6b62f6f58efe..9331d44d6963 100644
>>>> --- a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>> +++ b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>> @@ -30,6 +30,9 @@ properties:
>>>>      maximum: 32
>>>>      default: 32
>>>>  
>>>> +  ep-gpios:
>>>> +    description: Input GPIO configured for the PERST# signal.
>>>
>>> Missing maxItems. But more important: why existing property perst-gpios,
>>> which you already have there in common schema, is not correct for this case?
>>
>> I am confused... Where do you find perst-gpios defined for the rk3399 ?
>> Under Documentation/devicetree/bindings/pci/, the only schema I see using
>> perst-gpios property are for the qcom (Qualcomm) controllers.
> 
> You are right, it's so far only in Qualcomm.
> 
>> The RC bindings for the rockchip rk3399 PCIe controller
>> (pci/rockchip,rk3399-pcie.yaml) already define the ep-gpios property. So if
> 
> Any reason why this cannot be named like GPIO? Is there already a user
> of this in Linux kernel? Commit msg says nothing about this, so that's
> why I would expect name matching the signal.

The RC-mode PCIe controller node of the rk3399 DTS already defines the ep-gpios
property for RC side PERST# signal handling. So we simply reused the exact same
name to be consistent between RC and EP. I personnally have no preferences. If
there is an effort to rename such signal with some preferred pattern, I will
follow. For the EP node, there was no PERST signal handling in the driver and
no property defined for it, so any name is fine. "perst-gpios" would indeed be
a better name, but again, given that the RC controller node has ep-gpios, we
reused that. What is your recommendation here ?

> 
> Best regards,
> Krzysztof
> 

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 17/18] dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

[Krzysztof Kozlowski]

On 02/04/2024 01:36, Damien Le Moal wrote:
> On 4/1/24 18:57, Krzysztof Kozlowski wrote:
>> On 01/04/2024 01:06, Damien Le Moal wrote:
>>> On 3/30/24 18:16, Krzysztof Kozlowski wrote:
>>>> On 30/03/2024 05:19, Damien Le Moal wrote:
>>>>> From: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>>>
>>>>> Describe the `ep-gpios` property which is used to map the PERST# input
>>>>> signal for endpoint mode.
>>>>>
>>>>> Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>>> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
>>>>> ---
>>>>>  .../devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml       | 3 +++
>>>>>  1 file changed, 3 insertions(+)
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>> index 6b62f6f58efe..9331d44d6963 100644
>>>>> --- a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>> +++ b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>> @@ -30,6 +30,9 @@ properties:
>>>>>      maximum: 32
>>>>>      default: 32
>>>>>  
>>>>> +  ep-gpios:
>>>>> +    description: Input GPIO configured for the PERST# signal.
>>>>
>>>> Missing maxItems. But more important: why existing property perst-gpios,
>>>> which you already have there in common schema, is not correct for this case?
>>>
>>> I am confused... Where do you find perst-gpios defined for the rk3399 ?
>>> Under Documentation/devicetree/bindings/pci/, the only schema I see using
>>> perst-gpios property are for the qcom (Qualcomm) controllers.
>>
>> You are right, it's so far only in Qualcomm.
>>
>>> The RC bindings for the rockchip rk3399 PCIe controller
>>> (pci/rockchip,rk3399-pcie.yaml) already define the ep-gpios property. So if
>>
>> Any reason why this cannot be named like GPIO? Is there already a user
>> of this in Linux kernel? Commit msg says nothing about this, so that's
>> why I would expect name matching the signal.
> 
> The RC-mode PCIe controller node of the rk3399 DTS already defines the ep-gpios
> property for RC side PERST# signal handling. So we simply reused the exact same
> name to be consistent between RC and EP. I personnally have no preferences. If
> there is an effort to rename such signal with some preferred pattern, I will
> follow. For the EP node, there was no PERST signal handling in the driver and
> no property defined for it, so any name is fine. "perst-gpios" would indeed be
> a better name, but again, given that the RC controller node has ep-gpios, we
> reused that. What is your recommendation here ?

Actually I don't know, perst and ep would work for me. If you do not
have code for this in the driver yet (nothing is shared between ep and
host), then maybe let's go with perst to match the actual name.

Anyway, you need maxItems. I sent a patch for the other binding:
https://lore.kernel.org/all/20240401100058.15749-1-krzysztof.kozlowski@linaro.org/

Best regards,
Krzysztof

Re: [PATCH v2 17/18] dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

[Damien Le Moal]

On 4/2/24 16:33, Krzysztof Kozlowski wrote:
> On 02/04/2024 01:36, Damien Le Moal wrote:
>> On 4/1/24 18:57, Krzysztof Kozlowski wrote:
>>> On 01/04/2024 01:06, Damien Le Moal wrote:
>>>> On 3/30/24 18:16, Krzysztof Kozlowski wrote:
>>>>> On 30/03/2024 05:19, Damien Le Moal wrote:
>>>>>> From: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>>>>
>>>>>> Describe the `ep-gpios` property which is used to map the PERST# input
>>>>>> signal for endpoint mode.
>>>>>>
>>>>>> Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>>>> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
>>>>>> ---
>>>>>>  .../devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml       | 3 +++
>>>>>>  1 file changed, 3 insertions(+)
>>>>>>
>>>>>> diff --git a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>> index 6b62f6f58efe..9331d44d6963 100644
>>>>>> --- a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>> +++ b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>> @@ -30,6 +30,9 @@ properties:
>>>>>>      maximum: 32
>>>>>>      default: 32
>>>>>>  
>>>>>> +  ep-gpios:
>>>>>> +    description: Input GPIO configured for the PERST# signal.
>>>>>
>>>>> Missing maxItems. But more important: why existing property perst-gpios,
>>>>> which you already have there in common schema, is not correct for this case?
>>>>
>>>> I am confused... Where do you find perst-gpios defined for the rk3399 ?
>>>> Under Documentation/devicetree/bindings/pci/, the only schema I see using
>>>> perst-gpios property are for the qcom (Qualcomm) controllers.
>>>
>>> You are right, it's so far only in Qualcomm.
>>>
>>>> The RC bindings for the rockchip rk3399 PCIe controller
>>>> (pci/rockchip,rk3399-pcie.yaml) already define the ep-gpios property. So if
>>>
>>> Any reason why this cannot be named like GPIO? Is there already a user
>>> of this in Linux kernel? Commit msg says nothing about this, so that's
>>> why I would expect name matching the signal.
>>
>> The RC-mode PCIe controller node of the rk3399 DTS already defines the ep-gpios
>> property for RC side PERST# signal handling. So we simply reused the exact same
>> name to be consistent between RC and EP. I personnally have no preferences. If
>> there is an effort to rename such signal with some preferred pattern, I will
>> follow. For the EP node, there was no PERST signal handling in the driver and
>> no property defined for it, so any name is fine. "perst-gpios" would indeed be
>> a better name, but again, given that the RC controller node has ep-gpios, we
>> reused that. What is your recommendation here ?
> 
> Actually I don't know, perst and ep would work for me. If you do not
> have code for this in the driver yet (nothing is shared between ep and
> host), then maybe let's go with perst to match the actual name.

That works for me. The other simple solution would be to move the RC node
ep-gpios description to the common schema pci/rockchip,rk3399-pcie-common.yaml,
maybe ? Otherwise, perst-gpios like the Qualcomm schemas would be nice too.

> 
> Anyway, you need maxItems. I sent a patch for the other binding:
> https://lore.kernel.org/all/20240401100058.15749-1-krzysztof.kozlowski@linaro.org/

Thanks for that.

> 
> Best regards,
> Krzysztof
> 

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 17/18] dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

[Damien Le Moal]

On 4/2/24 16:33, Krzysztof Kozlowski wrote:
> On 02/04/2024 01:36, Damien Le Moal wrote:
>> On 4/1/24 18:57, Krzysztof Kozlowski wrote:
>>> On 01/04/2024 01:06, Damien Le Moal wrote:
>>>> On 3/30/24 18:16, Krzysztof Kozlowski wrote:
>>>>> On 30/03/2024 05:19, Damien Le Moal wrote:
>>>>>> From: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>>>>
>>>>>> Describe the `ep-gpios` property which is used to map the PERST# input
>>>>>> signal for endpoint mode.
>>>>>>
>>>>>> Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>>>> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
>>>>>> ---
>>>>>>  .../devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml       | 3 +++
>>>>>>  1 file changed, 3 insertions(+)
>>>>>>
>>>>>> diff --git a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>> index 6b62f6f58efe..9331d44d6963 100644
>>>>>> --- a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>> +++ b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>> @@ -30,6 +30,9 @@ properties:
>>>>>>      maximum: 32
>>>>>>      default: 32
>>>>>>  
>>>>>> +  ep-gpios:
>>>>>> +    description: Input GPIO configured for the PERST# signal.
>>>>>
>>>>> Missing maxItems. But more important: why existing property perst-gpios,
>>>>> which you already have there in common schema, is not correct for this case?
>>>>
>>>> I am confused... Where do you find perst-gpios defined for the rk3399 ?
>>>> Under Documentation/devicetree/bindings/pci/, the only schema I see using
>>>> perst-gpios property are for the qcom (Qualcomm) controllers.
>>>
>>> You are right, it's so far only in Qualcomm.
>>>
>>>> The RC bindings for the rockchip rk3399 PCIe controller
>>>> (pci/rockchip,rk3399-pcie.yaml) already define the ep-gpios property. So if
>>>
>>> Any reason why this cannot be named like GPIO? Is there already a user
>>> of this in Linux kernel? Commit msg says nothing about this, so that's
>>> why I would expect name matching the signal.
>>
>> The RC-mode PCIe controller node of the rk3399 DTS already defines the ep-gpios
>> property for RC side PERST# signal handling. So we simply reused the exact same
>> name to be consistent between RC and EP. I personnally have no preferences. If
>> there is an effort to rename such signal with some preferred pattern, I will
>> follow. For the EP node, there was no PERST signal handling in the driver and
>> no property defined for it, so any name is fine. "perst-gpios" would indeed be
>> a better name, but again, given that the RC controller node has ep-gpios, we
>> reused that. What is your recommendation here ?
> 
> Actually I don't know, perst and ep would work for me. If you do not
> have code for this in the driver yet (nothing is shared between ep and
> host), then maybe let's go with perst to match the actual name.

Forgot to add: the driver code for the EP PERST gpio handling is added in patch
18 of the series, after this one.

> 
> Anyway, you need maxItems. I sent a patch for the other binding:
> https://lore.kernel.org/all/20240401100058.15749-1-krzysztof.kozlowski@linaro.org/
> 
> Best regards,
> Krzysztof
> 

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 17/18] dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

[Damien Le Moal]

On 4/2/24 16:38, Damien Le Moal wrote:
> On 4/2/24 16:33, Krzysztof Kozlowski wrote:
>> On 02/04/2024 01:36, Damien Le Moal wrote:
>>> On 4/1/24 18:57, Krzysztof Kozlowski wrote:
>>>> On 01/04/2024 01:06, Damien Le Moal wrote:
>>>>> On 3/30/24 18:16, Krzysztof Kozlowski wrote:
>>>>>> On 30/03/2024 05:19, Damien Le Moal wrote:
>>>>>>> From: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>>>>>
>>>>>>> Describe the `ep-gpios` property which is used to map the PERST# input
>>>>>>> signal for endpoint mode.
>>>>>>>
>>>>>>> Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>>>>> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
>>>>>>> ---
>>>>>>>  .../devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml       | 3 +++
>>>>>>>  1 file changed, 3 insertions(+)
>>>>>>>
>>>>>>> diff --git a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>>> index 6b62f6f58efe..9331d44d6963 100644
>>>>>>> --- a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>>> +++ b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>>> @@ -30,6 +30,9 @@ properties:
>>>>>>>      maximum: 32
>>>>>>>      default: 32
>>>>>>>  
>>>>>>> +  ep-gpios:
>>>>>>> +    description: Input GPIO configured for the PERST# signal.
>>>>>>
>>>>>> Missing maxItems. But more important: why existing property perst-gpios,
>>>>>> which you already have there in common schema, is not correct for this case?
>>>>>
>>>>> I am confused... Where do you find perst-gpios defined for the rk3399 ?
>>>>> Under Documentation/devicetree/bindings/pci/, the only schema I see using
>>>>> perst-gpios property are for the qcom (Qualcomm) controllers.
>>>>
>>>> You are right, it's so far only in Qualcomm.
>>>>
>>>>> The RC bindings for the rockchip rk3399 PCIe controller
>>>>> (pci/rockchip,rk3399-pcie.yaml) already define the ep-gpios property. So if
>>>>
>>>> Any reason why this cannot be named like GPIO? Is there already a user
>>>> of this in Linux kernel? Commit msg says nothing about this, so that's
>>>> why I would expect name matching the signal.
>>>
>>> The RC-mode PCIe controller node of the rk3399 DTS already defines the ep-gpios
>>> property for RC side PERST# signal handling. So we simply reused the exact same
>>> name to be consistent between RC and EP. I personnally have no preferences. If
>>> there is an effort to rename such signal with some preferred pattern, I will
>>> follow. For the EP node, there was no PERST signal handling in the driver and
>>> no property defined for it, so any name is fine. "perst-gpios" would indeed be
>>> a better name, but again, given that the RC controller node has ep-gpios, we
>>> reused that. What is your recommendation here ?
>>
>> Actually I don't know, perst and ep would work for me. If you do not
>> have code for this in the driver yet (nothing is shared between ep and
>> host), then maybe let's go with perst to match the actual name.
> 
> That works for me. The other simple solution would be to move the RC node
> ep-gpios description to the common schema pci/rockchip,rk3399-pcie-common.yaml,
> maybe ? Otherwise, perst-gpios like the Qualcomm schemas would be nice too.

Thinking more about this, I think moving the ep-gpios description to the common
schema is the right thing to do given that the driver uses common code between
RC and EP to get that property. But if that is not acceptable, I can rename it
and get that property in the controller EP mode initialization code. That will
be add a little more code in the driver.

> 
>>
>> Anyway, you need maxItems. I sent a patch for the other binding:
>> https://lore.kernel.org/all/20240401100058.15749-1-krzysztof.kozlowski@linaro.org/
> 
> Thanks for that.
> 
>>
>> Best regards,
>> Krzysztof
>>
> 

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 00/18] Improve PCI memory mapping API

[Rick Wertenbroek]

On Sat, Mar 30, 2024 at 5:19 AM Damien Le Moal <dlemoal@kernel.org> wrote:
>
> This series introduces the new functions pci_epc_map_align(),
> pci_epc_mem_map() and pci_epc_mem_unmap() to improve handling of the
> PCI address mapping alignment constraints of endpoint controllers in a
> controller independent manner.
>
> The issue fixed is that the fixed alignment defined by the "align" field
> of struct pci_epc_features assumes that the alignment of the endpoint
> memory used to map a RC PCI address range is independent of the PCI
> address being mapped. But that is not the case for the rk3399 SoC
> controller: in endpoint mode, this controller uses the lower bits of the
> local endpoint memory address as the lower bits for the PCI addresses
> for data transfers. That is, when mapping local memory, one must take
> into account the number of bits of the RC PCI address that change from
> the start address of the mapping.
>
> To fix this, the new endpoint controller method .map_align is introduced
> and called from pci_epc_map_align(). This method is optional and for
> controllers that do not define it, the mapping information returned
> is based of the fixed alignment constraint as defined by the align
> feature.
>
> The functions pci_epc_mem_map() is a helper function which obtains
> mapping information, allocates endpoint controller memory according to
> the mapping size obtained and maps the memory. pci_epc_mem_map() unmaps
> and frees the endpoint memory.

This way of mapping is not only useful for the RK3399 but would also
help for the addition of other future PCI endpoint controller drivers.

For example, on several FPGA PCI endpoint IPs the window mapping is
also done by passing N bits from the mapped address and M bits from
the window mapping address (where N+M=bus width, e.g., 32 or 64).
Using AND/OR masks/operations to combine the bits for the hardware
address from the mapped address and map base uses less resources than
using add/subtract to get the hardware address from an unaligned map
base and offset. So I guess that more than a few IPs, being hard or
soft IPs, use this kind of mapping (to reduce size, logic, improve max
operating frequency, improve efficiency etc.)

Two major examples come to mind :
1) The AMD/Xilinx PCIe endpoint IP. The mapping is documentented in
"AXI Bridge for PCI Express Gen3 Subsystem Product Guide (PG194)" [1]
section BAR and Address Translation (Figure AXI to PCIe Address
Translation).
2) The Intel/Altera PCIe endpoint IP. The mapping is documented in
"Multi Channel DMA Intel® FPGA IP for PCI Express* User Guide" [2]
section 3.6. Root Port Address Translation Table Enablement.

Both those IPs don't have mainline support yet as PCIe endpoint
controllers but also use a similar kind of mapping as suggested here
for the RK3399. So these changes would also make the addition of these
controller drivers easier.

The new mapping scheme also makes it much clearer in the PCI endpoint
framework. Because without it some mapping operation would fail
because of alignment requirements in the controller, this requires
extra code and checks in the drivers that implement the endpoint
functions. With the current state of the PCI endpoint controller
framework there is no good way to express that the controller does an
AND/OR mask combination to create the hardware address and therefore
requires the map to be aligned to the window size, rather than doing a
window base addition with an offset (subtraction) in the mapping. This
could benefit from further clarification in the endpoint framework.

Best regards,
Rick

[1] https://docs.amd.com/r/en-US/pg194-axi-bridge-pcie-gen3/Address-Translation
[2] https://www.intel.com/content/www/us/en/docs/programmable/683821/23-4/

>
> This series is organized as follows:
>  - Patch 1 tidy up the epc core code
>  - Patch 2 and 3 introduce the new map_align endpoint controller method
>    and related epc functions.
>  - Patch 4 to 6 modify the test endpoint driver to use these new
>    functions and improve the code of this driver.
>  - Finally, Patch 7 to 18 fix the rk3399 endpoint driver, defining a
>    .map_align method for it and improving its overall code readability
>    and features.
>
> Changes from v1:
>  - Changed pci_epc_check_func() to pci_epc_function_is_valid() in patch
>    1.
>  - Removed patch "PCI: endpoint: Improve pci_epc_mem_alloc_addr()"
>    (former patch 2 of v1)
>  - Various typos cleanups all over. Also fixed some blank space
>    indentation.
>  - Added review tags
>
> Damien Le Moal (17):
>   PCI: endpoint: Introduce pci_epc_function_is_valid()
>   PCI: endpoint: Introduce pci_epc_map_align()
>   PCI: endpoint: Introduce pci_epc_mem_map()/unmap()
>   PCI: endpoint: test: Use pci_epc_mem_map/unmap()
>   PCI: endpoint: test: Synchronously cancel command handler work
>   PCI: endpoint: test: Implement link_down event operation
>   PCI: rockchip-ep: Fix address translation unit programming
>   PCI: rockchip-ep: Use a macro to define EP controller .align feature
>   PCI: rockchip-ep: Improve rockchip_pcie_ep_unmap_addr()
>   PCI: rockchip-ep: Improve rockchip_pcie_ep_map_addr()
>   PCI: rockchip-ep: Implement the map_align endpoint controller operation
>   PCI: rockchip-ep: Refactor rockchip_pcie_ep_probe() memory allocations
>   PCI: rockchip-ep: Refactor rockchip_pcie_ep_probe() MSI-X hiding
>   PCI: rockchip-ep: Refactor endpoint link training enable
>   PCI: rockship-ep: Introduce rockchip_pcie_ep_stop()
>   PCI: rockchip-ep: Improve link training
>   PCI: rockchip-ep: Handle PERST# signal in endpoint mode
>
> Wilfred Mallawa (1):
>   dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property
>
>  .../bindings/pci/rockchip,rk3399-pcie-ep.yaml |   3 +
>  drivers/pci/controller/pcie-rockchip-ep.c     | 393 ++++++++++++++----
>  drivers/pci/controller/pcie-rockchip.c        |  17 +-
>  drivers/pci/controller/pcie-rockchip.h        |  22 +
>  drivers/pci/endpoint/functions/pci-epf-test.c | 390 +++++++++--------
>  drivers/pci/endpoint/pci-epc-core.c           | 213 +++++++---
>  include/linux/pci-epc.h                       |  39 ++
>  7 files changed, 768 insertions(+), 309 deletions(-)
>
> --
> 2.44.0
>

Re: [PATCH v2 17/18] dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

[Krzysztof Kozlowski]

On 02/04/2024 09:55, Damien Le Moal wrote:
> On 4/2/24 16:38, Damien Le Moal wrote:
>> On 4/2/24 16:33, Krzysztof Kozlowski wrote:
>>> On 02/04/2024 01:36, Damien Le Moal wrote:
>>>> On 4/1/24 18:57, Krzysztof Kozlowski wrote:
>>>>> On 01/04/2024 01:06, Damien Le Moal wrote:
>>>>>> On 3/30/24 18:16, Krzysztof Kozlowski wrote:
>>>>>>> On 30/03/2024 05:19, Damien Le Moal wrote:
>>>>>>>> From: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>>>>>>
>>>>>>>> Describe the `ep-gpios` property which is used to map the PERST# input
>>>>>>>> signal for endpoint mode.
>>>>>>>>
>>>>>>>> Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
>>>>>>>> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
>>>>>>>> ---
>>>>>>>>  .../devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml       | 3 +++
>>>>>>>>  1 file changed, 3 insertions(+)
>>>>>>>>
>>>>>>>> diff --git a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>>>> index 6b62f6f58efe..9331d44d6963 100644
>>>>>>>> --- a/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>>>> +++ b/Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie-ep.yaml
>>>>>>>> @@ -30,6 +30,9 @@ properties:
>>>>>>>>      maximum: 32
>>>>>>>>      default: 32
>>>>>>>>  
>>>>>>>> +  ep-gpios:
>>>>>>>> +    description: Input GPIO configured for the PERST# signal.
>>>>>>>
>>>>>>> Missing maxItems. But more important: why existing property perst-gpios,
>>>>>>> which you already have there in common schema, is not correct for this case?
>>>>>>
>>>>>> I am confused... Where do you find perst-gpios defined for the rk3399 ?
>>>>>> Under Documentation/devicetree/bindings/pci/, the only schema I see using
>>>>>> perst-gpios property are for the qcom (Qualcomm) controllers.
>>>>>
>>>>> You are right, it's so far only in Qualcomm.
>>>>>
>>>>>> The RC bindings for the rockchip rk3399 PCIe controller
>>>>>> (pci/rockchip,rk3399-pcie.yaml) already define the ep-gpios property. So if
>>>>>
>>>>> Any reason why this cannot be named like GPIO? Is there already a user
>>>>> of this in Linux kernel? Commit msg says nothing about this, so that's
>>>>> why I would expect name matching the signal.
>>>>
>>>> The RC-mode PCIe controller node of the rk3399 DTS already defines the ep-gpios
>>>> property for RC side PERST# signal handling. So we simply reused the exact same
>>>> name to be consistent between RC and EP. I personnally have no preferences. If
>>>> there is an effort to rename such signal with some preferred pattern, I will
>>>> follow. For the EP node, there was no PERST signal handling in the driver and
>>>> no property defined for it, so any name is fine. "perst-gpios" would indeed be
>>>> a better name, but again, given that the RC controller node has ep-gpios, we
>>>> reused that. What is your recommendation here ?
>>>
>>> Actually I don't know, perst and ep would work for me. If you do not
>>> have code for this in the driver yet (nothing is shared between ep and
>>> host), then maybe let's go with perst to match the actual name.
>>
>> That works for me. The other simple solution would be to move the RC node
>> ep-gpios description to the common schema pci/rockchip,rk3399-pcie-common.yaml,
>> maybe ? Otherwise, perst-gpios like the Qualcomm schemas would be nice too.
> 
> Thinking more about this, I think moving the ep-gpios description to the common
> schema is the right thing to do given that the driver uses common code between
> RC and EP to get that property. But if that is not acceptable, I can rename it
> and get that property in the controller EP mode initialization code. That will
> be add a little more code in the driver.

I forgot that it is actually the same hardware, so if host has
"ep-gpios" already then EP mode should have the same property. Common
schema is good idea.


Best regards,
Krzysztof

Re: [PATCH v2 17/18] dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property

[Damien Le Moal]

On 4/3/24 03:10, Krzysztof Kozlowski wrote:
>> Thinking more about this, I think moving the ep-gpios description to the common
>> schema is the right thing to do given that the driver uses common code between
>> RC and EP to get that property. But if that is not acceptable, I can rename it
>> and get that property in the controller EP mode initialization code. That will
>> be add a little more code in the driver.
> 
> I forgot that it is actually the same hardware, so if host has
> "ep-gpios" already then EP mode should have the same property. Common
> schema is good idea.

OK. But this will conflict with the patch you sent to add the missing maxItem.
Is that patch a fix or is it for 6.10 ? If it is the former, I can wait for
next week to rebase on rc3 and avoid a conflict.

> 
> 
> Best regards,
> Krzysztof
> 

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 01/18] PCI: endpoint: Introduce pci_epc_function_is_valid()

[Manivannan Sadhasivam]

On Sat, Mar 30, 2024 at 01:19:11PM +0900, Damien Le Moal wrote:
> Introduce the epc core helper function pci_epc_function_is_valid() to
> verify that an epc pointer, a physical function number and a virtual
> function number are all valid. This avoids repeating the code pattern:
> 
> if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
> 	return err;
> 
> if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> 	return err;
> 
> in many functions of the endpoint controller core code.
> 
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

One nit below. With that fixed,

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

> ---
>  drivers/pci/endpoint/pci-epc-core.c | 79 +++++++++++------------------
>  1 file changed, 31 insertions(+), 48 deletions(-)
> 
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index da3fc0795b0b..754afd115bbd 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -126,6 +126,18 @@ enum pci_barno pci_epc_get_next_free_bar(const struct pci_epc_features
>  }
>  EXPORT_SYMBOL_GPL(pci_epc_get_next_free_bar);
>  
> +static inline bool pci_epc_function_is_valid(struct pci_epc *epc,
> +					     u8 func_no, u8 vfunc_no)

No need to add 'inline' keyword to function definitions in a .c file. Compiler
will handle that.

- Mani

> +{
> +	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
> +		return false;
> +
> +	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +		return false;
> +
> +	return true;
> +}
> +
>  /**
>   * pci_epc_get_features() - get the features supported by EPC
>   * @epc: the features supported by *this* EPC device will be returned
> @@ -143,10 +155,7 @@ const struct pci_epc_features *pci_epc_get_features(struct pci_epc *epc,
>  {
>  	const struct pci_epc_features *epc_features;
>  
> -	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
> -		return NULL;
> -
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>  		return NULL;
>  
>  	if (!epc->ops->get_features)
> @@ -216,10 +225,7 @@ int pci_epc_raise_irq(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  {
>  	int ret;
>  
> -	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
> -		return -EINVAL;
> -
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>  		return -EINVAL;
>  
>  	if (!epc->ops->raise_irq)
> @@ -260,10 +266,7 @@ int pci_epc_map_msi_irq(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  {
>  	int ret;
>  
> -	if (IS_ERR_OR_NULL(epc))
> -		return -EINVAL;
> -
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>  		return -EINVAL;
>  
>  	if (!epc->ops->map_msi_irq)
> @@ -291,10 +294,7 @@ int pci_epc_get_msi(struct pci_epc *epc, u8 func_no, u8 vfunc_no)
>  {
>  	int interrupt;
>  
> -	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
> -		return 0;
> -
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>  		return 0;
>  
>  	if (!epc->ops->get_msi)
> @@ -327,11 +327,10 @@ int pci_epc_set_msi(struct pci_epc *epc, u8 func_no, u8 vfunc_no, u8 interrupts)
>  	int ret;
>  	u8 encode_int;
>  
> -	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions ||
> -	    interrupts < 1 || interrupts > 32)
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>  		return -EINVAL;
>  
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +	if (interrupts < 1 || interrupts > 32)
>  		return -EINVAL;
>  
>  	if (!epc->ops->set_msi)
> @@ -359,10 +358,7 @@ int pci_epc_get_msix(struct pci_epc *epc, u8 func_no, u8 vfunc_no)
>  {
>  	int interrupt;
>  
> -	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
> -		return 0;
> -
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>  		return 0;
>  
>  	if (!epc->ops->get_msix)
> @@ -395,11 +391,10 @@ int pci_epc_set_msix(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  {
>  	int ret;
>  
> -	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions ||
> -	    interrupts < 1 || interrupts > 2048)
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>  		return -EINVAL;
>  
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +	if (interrupts < 1 || interrupts > 2048)
>  		return -EINVAL;
>  
>  	if (!epc->ops->set_msix)
> @@ -426,10 +421,7 @@ EXPORT_SYMBOL_GPL(pci_epc_set_msix);
>  void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  			phys_addr_t phys_addr)
>  {
> -	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
> -		return;
> -
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>  		return;
>  
>  	if (!epc->ops->unmap_addr)
> @@ -457,10 +449,7 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  {
>  	int ret;
>  
> -	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
> -		return -EINVAL;
> -
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>  		return -EINVAL;
>  
>  	if (!epc->ops->map_addr)
> @@ -487,12 +476,11 @@ EXPORT_SYMBOL_GPL(pci_epc_map_addr);
>  void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  		       struct pci_epf_bar *epf_bar)
>  {
> -	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions ||
> -	    (epf_bar->barno == BAR_5 &&
> -	     epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64))
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>  		return;
>  
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +	if (epf_bar->barno == BAR_5 &&
> +	    epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64)
>  		return;
>  
>  	if (!epc->ops->clear_bar)
> @@ -519,18 +507,16 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  	int ret;
>  	int flags = epf_bar->flags;
>  
> -	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions ||
> -	    (epf_bar->barno == BAR_5 &&
> -	     flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ||
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
> +		return -EINVAL;
> +
> +	if ((epf_bar->barno == BAR_5 && flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ||
>  	    (flags & PCI_BASE_ADDRESS_SPACE_IO &&
>  	     flags & PCI_BASE_ADDRESS_IO_MASK) ||
>  	    (upper_32_bits(epf_bar->size) &&
>  	     !(flags & PCI_BASE_ADDRESS_MEM_TYPE_64)))
>  		return -EINVAL;
>  
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> -		return -EINVAL;
> -
>  	if (!epc->ops->set_bar)
>  		return 0;
>  
> @@ -559,10 +545,7 @@ int pci_epc_write_header(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  {
>  	int ret;
>  
> -	if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
> -		return -EINVAL;
> -
> -	if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>  		return -EINVAL;
>  
>  	/* Only Virtual Function #1 has deviceID */
> -- 
> 2.44.0
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()

[Manivannan Sadhasivam]

On Sat, Mar 30, 2024 at 01:19:12PM +0900, Damien Le Moal wrote:
> Some endpoint controllers have requirements on the alignment of the
> controller physical memory address that must be used to map a RC PCI
> address region. For instance, the rockchip endpoint controller uses
> at most the lower 20 bits of a physical memory address region as the
> lower bits of an RC PCI address. For mapping a PCI address region of
> size bytes starting from pci_addr, the exact number of address bits
> used is the number of address bits changing in the address range
> [pci_addr..pci_addr + size - 1].
> 
> For this example, this creates the following constraints:
> 1) The offset into the controller physical memory allocated for a
>    mapping depends on the mapping size *and* the starting PCI address
>    for the mapping.
> 2) A mapping size cannot exceed the controller windows size (1MB) minus
>    the offset needed into the allocated physical memory, which can end
>    up being a smaller size than the desired mapping size.
> 
> Handling these constraints independently of the controller being used in
> a PCI EP function driver is not possible with the current EPC API as
> it only provides the ->align field in struct pci_epc_features.
> Furthermore, this alignment is static and does not depend on a mapping
> pci address and size.
> 
> Solve this by introducing the function pci_epc_map_align() and the
> endpoint controller operation ->map_align to allow endpoint function
> drivers to obtain the size and the offset into a controller address
> region that must be used to map an RC PCI address region. The size
> of the physical address region provided by pci_epc_map_align() can then
> be used as the size argument for the function pci_epc_mem_alloc_addr().
> The offset into the allocated controller memory can be used to
> correctly handle data transfers. Of note is that pci_epc_map_align() may
> indicate upon return a mapping size that is smaller (but not 0) than the
> requested PCI address region size. For such case, an endpoint function
> driver must handle data transfers in fragments.
> 

Is there any incentive in exposing pci_epc_map_align()? I mean, why can't it be
hidden inside the new alloc() API itself?

Furthermore, is it possible to avoid the map_align() callback and handle the
alignment within the EPC driver?

- Mani

> The controller operation ->map_align is optional: controllers that do
> not have any address alignment constraints for mapping a RC PCI address
> region do not need to implement this operation. For such controllers,
> pci_epc_map_align() always returns the mapping size as equal
> to the requested size and an offset equal to 0.
> 
> The structure pci_epc_map is introduced to represent a mapping start PCI
> address, size and the size and offset into the controller memory needed
> for mapping the PCI address region.
> 
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>  drivers/pci/endpoint/pci-epc-core.c | 66 +++++++++++++++++++++++++++++
>  include/linux/pci-epc.h             | 33 +++++++++++++++
>  2 files changed, 99 insertions(+)
> 
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 754afd115bbd..37758ca91d7f 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -433,6 +433,72 @@ void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  }
>  EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
>  
> +/**
> + * pci_epc_map_align() - Get the offset into and the size of a controller memory
> + *			 address region needed to map a RC PCI address region
> + * @epc: the EPC device on which address is allocated
> + * @func_no: the physical endpoint function number in the EPC device
> + * @vfunc_no: the virtual endpoint function number in the physical function
> + * @pci_addr: PCI address to which the physical address should be mapped
> + * @size: the size of the mapping starting from @pci_addr
> + * @map: populate here the actual size and offset into the controller memory
> + *       that must be allocated for the mapping
> + *
> + * Invoke the controller map_align operation to obtain the size and the offset
> + * into a controller address region that must be allocated to map @size
> + * bytes of the RC PCI address space starting from @pci_addr.
> + *
> + * The size of the mapping that can be handled by the controller is indicated
> + * using the pci_size field of @map. This size may be smaller than the requested
> + * @size. In such case, the function driver must handle the mapping using
> + * several fragments. The offset into the controller memory for the effective
> + * mapping of the @pci_addr..@pci_addr+@map->pci_size address range is indicated
> + * using the map_ofst field of @map.
> + */
> +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		      u64 pci_addr, size_t size, struct pci_epc_map *map)
> +{
> +	const struct pci_epc_features *features;
> +	size_t mask;
> +	int ret;
> +
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
> +		return -EINVAL;
> +
> +	if (!size || !map)
> +		return -EINVAL;
> +
> +	memset(map, 0, sizeof(*map));
> +	map->pci_addr = pci_addr;
> +	map->pci_size = size;
> +
> +	if (epc->ops->map_align) {
> +		mutex_lock(&epc->lock);
> +		ret = epc->ops->map_align(epc, func_no, vfunc_no, map);
> +		mutex_unlock(&epc->lock);
> +		return ret;
> +	}
> +
> +	/*
> +	 * Assume a fixed alignment constraint as specified by the controller
> +	 * features.
> +	 */
> +	features = pci_epc_get_features(epc, func_no, vfunc_no);
> +	if (!features || !features->align) {
> +		map->map_pci_addr = pci_addr;
> +		map->map_size = size;
> +		map->map_ofst = 0;

These values are overwritten anyway below.

> +	}
> +
> +	mask = features->align - 1;
> +	map->map_pci_addr = map->pci_addr & ~mask;
> +	map->map_ofst = map->pci_addr & mask;
> +	map->map_size = ALIGN(map->map_ofst + map->pci_size, features->align);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(pci_epc_map_align);
> +
>  /**
>   * pci_epc_map_addr() - map CPU address to PCI address
>   * @epc: the EPC device on which address is allocated
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index cc2f70d061c8..8cfb4aaf2628 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -32,11 +32,40 @@ pci_epc_interface_string(enum pci_epc_interface_type type)
>  	}
>  }
>  
> +/**
> + * struct pci_epc_map - information about EPC memory for mapping a RC PCI
> + *                      address range
> + * @pci_addr: start address of the RC PCI address range to map
> + * @pci_size: size of the RC PCI address range to map
> + * @map_pci_addr: RC PCI address used as the first address mapped
> + * @map_size: size of the controller memory needed for the mapping
> + * @map_ofst: offset into the controller memory needed for the mapping
> + * @phys_base: base physical address of the allocated EPC memory
> + * @phys_addr: physical address at which @pci_addr is mapped
> + * @virt_base: base virtual address of the allocated EPC memory
> + * @virt_addr: virtual address at which @pci_addr is mapped
> + */
> +struct pci_epc_map {
> +	phys_addr_t	pci_addr;
> +	size_t		pci_size;
> +
> +	phys_addr_t	map_pci_addr;
> +	size_t		map_size;
> +	phys_addr_t	map_ofst;
> +
> +	phys_addr_t	phys_base;
> +	phys_addr_t	phys_addr;
> +	void __iomem	*virt_base;
> +	void __iomem	*virt_addr;
> +};
> +
>  /**
>   * struct pci_epc_ops - set of function pointers for performing EPC operations
>   * @write_header: ops to populate configuration space header
>   * @set_bar: ops to configure the BAR
>   * @clear_bar: ops to reset the BAR
> + * @map_align: operation to get the size and offset into a controller memory
> + *             window needed to map an RC PCI address region
>   * @map_addr: ops to map CPU address to PCI address
>   * @unmap_addr: ops to unmap CPU address and PCI address
>   * @set_msi: ops to set the requested number of MSI interrupts in the MSI
> @@ -61,6 +90,8 @@ struct pci_epc_ops {
>  			   struct pci_epf_bar *epf_bar);
>  	void	(*clear_bar)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  			     struct pci_epf_bar *epf_bar);
> +	int	(*map_align)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +			    struct pci_epc_map *map);
>  	int	(*map_addr)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  			    phys_addr_t addr, u64 pci_addr, size_t size);
>  	void	(*unmap_addr)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> @@ -234,6 +265,8 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  		    struct pci_epf_bar *epf_bar);
>  void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  		       struct pci_epf_bar *epf_bar);
> +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		      u64 pci_addr, size_t size, struct pci_epc_map *map);
>  int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  		     phys_addr_t phys_addr,
>  		     u64 pci_addr, size_t size);
> -- 
> 2.44.0
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 05/18] PCI: endpoint: test: Synchronously cancel command handler work

[Manivannan Sadhasivam]

On Sat, Mar 30, 2024 at 01:19:15PM +0900, Damien Le Moal wrote:
> Replace the call to cancel_delayed_work() with a call to
> cancel_delayed_work_sync() in pci_epf_test_unbind(). This ensures that
> the command handler is really stopped when proceeding with dma and bar
> cleanup.
> 
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

- Mani

> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> ---
>  drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 0e285e539538..ab40c3182677 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -709,7 +709,7 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
>  	struct pci_epf_bar *epf_bar;
>  	int bar;
>  
> -	cancel_delayed_work(&epf_test->cmd_handler);
> +	cancel_delayed_work_sync(&epf_test->cmd_handler);
>  	pci_epf_test_clean_dma_chan(epf_test);
>  	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
>  		epf_bar = &epf->bar[bar];
> -- 
> 2.44.0
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 06/18] PCI: endpoint: test: Implement link_down event operation

[Manivannan Sadhasivam]

On Sat, Mar 30, 2024 at 01:19:16PM +0900, Damien Le Moal wrote:
> Implement the link_down event operation to stop the command execution
> delayed work when the endpoint controller notifies a link down event.
> 
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

This patch is already part of another series I posted [1] and under review. So
this can be dropped.

- Mani

[1] https://lore.kernel.org/linux-pci/20240401-pci-epf-rework-v2-9-970dbe90b99d@linaro.org/

> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> ---
>  drivers/pci/endpoint/functions/pci-epf-test.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index ab40c3182677..e6d4e1747c9f 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -824,9 +824,19 @@ static int pci_epf_test_link_up(struct pci_epf *epf)
>  	return 0;
>  }
>  
> +static int pci_epf_test_link_down(struct pci_epf *epf)
> +{
> +	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
> +
> +	cancel_delayed_work_sync(&epf_test->cmd_handler);
> +
> +	return 0;
> +}
> +
>  static const struct pci_epc_event_ops pci_epf_test_event_ops = {
>  	.core_init = pci_epf_test_core_init,
>  	.link_up = pci_epf_test_link_up,
> +	.link_down = pci_epf_test_link_down,
>  };
>  
>  static int pci_epf_test_alloc_space(struct pci_epf *epf)
> -- 
> 2.44.0
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 00/18] Improve PCI memory mapping API

[Manivannan Sadhasivam]

On Sat, Mar 30, 2024 at 01:19:10PM +0900, Damien Le Moal wrote:
> This series introduces the new functions pci_epc_map_align(),
> pci_epc_mem_map() and pci_epc_mem_unmap() to improve handling of the
> PCI address mapping alignment constraints of endpoint controllers in a
> controller independent manner.
> 
> The issue fixed is that the fixed alignment defined by the "align" field
> of struct pci_epc_features assumes that the alignment of the endpoint
> memory used to map a RC PCI address range is independent of the PCI
> address being mapped. But that is not the case for the rk3399 SoC
> controller: in endpoint mode, this controller uses the lower bits of the
> local endpoint memory address as the lower bits for the PCI addresses
> for data transfers. That is, when mapping local memory, one must take
> into account the number of bits of the RC PCI address that change from
> the start address of the mapping.
> 
> To fix this, the new endpoint controller method .map_align is introduced
> and called from pci_epc_map_align(). This method is optional and for
> controllers that do not define it, the mapping information returned
> is based of the fixed alignment constraint as defined by the align
> feature.
> 
> The functions pci_epc_mem_map() is a helper function which obtains
> mapping information, allocates endpoint controller memory according to
> the mapping size obtained and maps the memory. pci_epc_mem_map() unmaps
> and frees the endpoint memory.
> 
> This series is organized as follows:
>  - Patch 1 tidy up the epc core code
>  - Patch 2 and 3 introduce the new map_align endpoint controller method
>    and related epc functions.
>  - Patch 4 to 6 modify the test endpoint driver to use these new
>    functions and improve the code of this driver.

While posting the next version, please split the endpoint patches into a
separate series. It helps in code review and can be applied separately.

- Mani

>  - Finally, Patch 7 to 18 fix the rk3399 endpoint driver, defining a
>    .map_align method for it and improving its overall code readability
>    and features.
> 
> Changes from v1:
>  - Changed pci_epc_check_func() to pci_epc_function_is_valid() in patch
>    1.
>  - Removed patch "PCI: endpoint: Improve pci_epc_mem_alloc_addr()"
>    (former patch 2 of v1)
>  - Various typos cleanups all over. Also fixed some blank space
>    indentation.
>  - Added review tags
> 
> Damien Le Moal (17):
>   PCI: endpoint: Introduce pci_epc_function_is_valid()
>   PCI: endpoint: Introduce pci_epc_map_align()
>   PCI: endpoint: Introduce pci_epc_mem_map()/unmap()
>   PCI: endpoint: test: Use pci_epc_mem_map/unmap()
>   PCI: endpoint: test: Synchronously cancel command handler work
>   PCI: endpoint: test: Implement link_down event operation
>   PCI: rockchip-ep: Fix address translation unit programming
>   PCI: rockchip-ep: Use a macro to define EP controller .align feature
>   PCI: rockchip-ep: Improve rockchip_pcie_ep_unmap_addr()
>   PCI: rockchip-ep: Improve rockchip_pcie_ep_map_addr()
>   PCI: rockchip-ep: Implement the map_align endpoint controller operation
>   PCI: rockchip-ep: Refactor rockchip_pcie_ep_probe() memory allocations
>   PCI: rockchip-ep: Refactor rockchip_pcie_ep_probe() MSI-X hiding
>   PCI: rockchip-ep: Refactor endpoint link training enable
>   PCI: rockship-ep: Introduce rockchip_pcie_ep_stop()
>   PCI: rockchip-ep: Improve link training
>   PCI: rockchip-ep: Handle PERST# signal in endpoint mode
> 
> Wilfred Mallawa (1):
>   dt-bindings: pci: rockchip,rk3399-pcie-ep: Add ep-gpios property
> 
>  .../bindings/pci/rockchip,rk3399-pcie-ep.yaml |   3 +
>  drivers/pci/controller/pcie-rockchip-ep.c     | 393 ++++++++++++++----
>  drivers/pci/controller/pcie-rockchip.c        |  17 +-
>  drivers/pci/controller/pcie-rockchip.h        |  22 +
>  drivers/pci/endpoint/functions/pci-epf-test.c | 390 +++++++++--------
>  drivers/pci/endpoint/pci-epc-core.c           | 213 +++++++---
>  include/linux/pci-epc.h                       |  39 ++
>  7 files changed, 768 insertions(+), 309 deletions(-)
> 
> -- 
> 2.44.0
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()

[Damien Le Moal]

On 4/3/24 16:45, Manivannan Sadhasivam wrote:
> On Sat, Mar 30, 2024 at 01:19:12PM +0900, Damien Le Moal wrote:
>> Some endpoint controllers have requirements on the alignment of the
>> controller physical memory address that must be used to map a RC PCI
>> address region. For instance, the rockchip endpoint controller uses
>> at most the lower 20 bits of a physical memory address region as the
>> lower bits of an RC PCI address. For mapping a PCI address region of
>> size bytes starting from pci_addr, the exact number of address bits
>> used is the number of address bits changing in the address range
>> [pci_addr..pci_addr + size - 1].
>>
>> For this example, this creates the following constraints:
>> 1) The offset into the controller physical memory allocated for a
>>    mapping depends on the mapping size *and* the starting PCI address
>>    for the mapping.
>> 2) A mapping size cannot exceed the controller windows size (1MB) minus
>>    the offset needed into the allocated physical memory, which can end
>>    up being a smaller size than the desired mapping size.
>>
>> Handling these constraints independently of the controller being used in
>> a PCI EP function driver is not possible with the current EPC API as
>> it only provides the ->align field in struct pci_epc_features.
>> Furthermore, this alignment is static and does not depend on a mapping
>> pci address and size.
>>
>> Solve this by introducing the function pci_epc_map_align() and the
>> endpoint controller operation ->map_align to allow endpoint function
>> drivers to obtain the size and the offset into a controller address
>> region that must be used to map an RC PCI address region. The size
>> of the physical address region provided by pci_epc_map_align() can then
>> be used as the size argument for the function pci_epc_mem_alloc_addr().
>> The offset into the allocated controller memory can be used to
>> correctly handle data transfers. Of note is that pci_epc_map_align() may
>> indicate upon return a mapping size that is smaller (but not 0) than the
>> requested PCI address region size. For such case, an endpoint function
>> driver must handle data transfers in fragments.
>>
> 
> Is there any incentive in exposing pci_epc_map_align()? I mean, why can't it be
> hidden inside the new alloc() API itself?

I could drop pci_epc_map_align(), but the idea here was to have an API that is
not restrictive. E.g., a function driver could allocate memory, keep it and
repetedly use map_align and map() function to remap it to different PCI
addresses. With your suggestion, that would not be possible.

> 
> Furthermore, is it possible to avoid the map_align() callback and handle the
> alignment within the EPC driver?

I am not so sure that this is possible because handling the alignment can
potentially result in changing the amount of memory to allocate, based on the
PCI address also. So the allocation API would need to change, a lot.

>> +	/*
>> +	 * Assume a fixed alignment constraint as specified by the controller
>> +	 * features.
>> +	 */
>> +	features = pci_epc_get_features(epc, func_no, vfunc_no);
>> +	if (!features || !features->align) {
>> +		map->map_pci_addr = pci_addr;
>> +		map->map_size = size;
>> +		map->map_ofst = 0;
> 
> These values are overwritten anyway below.

Looks like "return" got dropped. Bug. Will re-add it.


-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 00/18] Improve PCI memory mapping API

[Damien Le Moal]

On 4/3/24 16:50, Manivannan Sadhasivam wrote:
> On Sat, Mar 30, 2024 at 01:19:10PM +0900, Damien Le Moal wrote:
>> This series introduces the new functions pci_epc_map_align(),
>> pci_epc_mem_map() and pci_epc_mem_unmap() to improve handling of the
>> PCI address mapping alignment constraints of endpoint controllers in a
>> controller independent manner.
>>
>> The issue fixed is that the fixed alignment defined by the "align" field
>> of struct pci_epc_features assumes that the alignment of the endpoint
>> memory used to map a RC PCI address range is independent of the PCI
>> address being mapped. But that is not the case for the rk3399 SoC
>> controller: in endpoint mode, this controller uses the lower bits of the
>> local endpoint memory address as the lower bits for the PCI addresses
>> for data transfers. That is, when mapping local memory, one must take
>> into account the number of bits of the RC PCI address that change from
>> the start address of the mapping.
>>
>> To fix this, the new endpoint controller method .map_align is introduced
>> and called from pci_epc_map_align(). This method is optional and for
>> controllers that do not define it, the mapping information returned
>> is based of the fixed alignment constraint as defined by the align
>> feature.
>>
>> The functions pci_epc_mem_map() is a helper function which obtains
>> mapping information, allocates endpoint controller memory according to
>> the mapping size obtained and maps the memory. pci_epc_mem_map() unmaps
>> and frees the endpoint memory.
>>
>> This series is organized as follows:
>>  - Patch 1 tidy up the epc core code
>>  - Patch 2 and 3 introduce the new map_align endpoint controller method
>>    and related epc functions.
>>  - Patch 4 to 6 modify the test endpoint driver to use these new
>>    functions and improve the code of this driver.
> 
> While posting the next version, please split the endpoint patches into a
> separate series. It helps in code review and can be applied separately.

Which patches ? They are all endpoint related:
 (1) Core code
 (2) test function driver
 (3) rockchip rk3399 controller

(2) and (3) depend on the patches in (1), so splitting the series is a big
possible only if (1) is applied first, so that is a source of delays and breaks
the context of the patches...

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()

[Manivannan Sadhasivam]

On Wed, Apr 03, 2024 at 04:54:32PM +0900, Damien Le Moal wrote:
> On 4/3/24 16:45, Manivannan Sadhasivam wrote:
> > On Sat, Mar 30, 2024 at 01:19:12PM +0900, Damien Le Moal wrote:
> >> Some endpoint controllers have requirements on the alignment of the
> >> controller physical memory address that must be used to map a RC PCI
> >> address region. For instance, the rockchip endpoint controller uses
> >> at most the lower 20 bits of a physical memory address region as the
> >> lower bits of an RC PCI address. For mapping a PCI address region of
> >> size bytes starting from pci_addr, the exact number of address bits
> >> used is the number of address bits changing in the address range
> >> [pci_addr..pci_addr + size - 1].
> >>
> >> For this example, this creates the following constraints:
> >> 1) The offset into the controller physical memory allocated for a
> >>    mapping depends on the mapping size *and* the starting PCI address
> >>    for the mapping.
> >> 2) A mapping size cannot exceed the controller windows size (1MB) minus
> >>    the offset needed into the allocated physical memory, which can end
> >>    up being a smaller size than the desired mapping size.
> >>
> >> Handling these constraints independently of the controller being used in
> >> a PCI EP function driver is not possible with the current EPC API as
> >> it only provides the ->align field in struct pci_epc_features.
> >> Furthermore, this alignment is static and does not depend on a mapping
> >> pci address and size.
> >>
> >> Solve this by introducing the function pci_epc_map_align() and the
> >> endpoint controller operation ->map_align to allow endpoint function
> >> drivers to obtain the size and the offset into a controller address
> >> region that must be used to map an RC PCI address region. The size
> >> of the physical address region provided by pci_epc_map_align() can then
> >> be used as the size argument for the function pci_epc_mem_alloc_addr().
> >> The offset into the allocated controller memory can be used to
> >> correctly handle data transfers. Of note is that pci_epc_map_align() may
> >> indicate upon return a mapping size that is smaller (but not 0) than the
> >> requested PCI address region size. For such case, an endpoint function
> >> driver must handle data transfers in fragments.
> >>
> > 
> > Is there any incentive in exposing pci_epc_map_align()? I mean, why can't it be
> > hidden inside the new alloc() API itself?
> 
> I could drop pci_epc_map_align(), but the idea here was to have an API that is
> not restrictive. E.g., a function driver could allocate memory, keep it and
> repetedly use map_align and map() function to remap it to different PCI
> addresses. With your suggestion, that would not be possible.
> 

Is there any requirement currently? If not, let's try to introduce it when the
actual requirement comes.

> > 
> > Furthermore, is it possible to avoid the map_align() callback and handle the
> > alignment within the EPC driver?
> 
> I am not so sure that this is possible because handling the alignment can
> potentially result in changing the amount of memory to allocate, based on the
> PCI address also. So the allocation API would need to change, a lot.
> 

Hmm, looking at patch 11/18, I think it might become complicated.

- Mani

> >> +	/*
> >> +	 * Assume a fixed alignment constraint as specified by the controller
> >> +	 * features.
> >> +	 */
> >> +	features = pci_epc_get_features(epc, func_no, vfunc_no);
> >> +	if (!features || !features->align) {
> >> +		map->map_pci_addr = pci_addr;
> >> +		map->map_size = size;
> >> +		map->map_ofst = 0;
> > 
> > These values are overwritten anyway below.
> 
> Looks like "return" got dropped. Bug. Will re-add it.
> 
> 
> -- 
> Damien Le Moal
> Western Digital Research
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 00/18] Improve PCI memory mapping API

[Manivannan Sadhasivam]

On Wed, Apr 03, 2024 at 04:58:42PM +0900, Damien Le Moal wrote:
> On 4/3/24 16:50, Manivannan Sadhasivam wrote:
> > On Sat, Mar 30, 2024 at 01:19:10PM +0900, Damien Le Moal wrote:
> >> This series introduces the new functions pci_epc_map_align(),
> >> pci_epc_mem_map() and pci_epc_mem_unmap() to improve handling of the
> >> PCI address mapping alignment constraints of endpoint controllers in a
> >> controller independent manner.
> >>
> >> The issue fixed is that the fixed alignment defined by the "align" field
> >> of struct pci_epc_features assumes that the alignment of the endpoint
> >> memory used to map a RC PCI address range is independent of the PCI
> >> address being mapped. But that is not the case for the rk3399 SoC
> >> controller: in endpoint mode, this controller uses the lower bits of the
> >> local endpoint memory address as the lower bits for the PCI addresses
> >> for data transfers. That is, when mapping local memory, one must take
> >> into account the number of bits of the RC PCI address that change from
> >> the start address of the mapping.
> >>
> >> To fix this, the new endpoint controller method .map_align is introduced
> >> and called from pci_epc_map_align(). This method is optional and for
> >> controllers that do not define it, the mapping information returned
> >> is based of the fixed alignment constraint as defined by the align
> >> feature.
> >>
> >> The functions pci_epc_mem_map() is a helper function which obtains
> >> mapping information, allocates endpoint controller memory according to
> >> the mapping size obtained and maps the memory. pci_epc_mem_map() unmaps
> >> and frees the endpoint memory.
> >>
> >> This series is organized as follows:
> >>  - Patch 1 tidy up the epc core code
> >>  - Patch 2 and 3 introduce the new map_align endpoint controller method
> >>    and related epc functions.
> >>  - Patch 4 to 6 modify the test endpoint driver to use these new
> >>    functions and improve the code of this driver.
> > 
> > While posting the next version, please split the endpoint patches into a
> > separate series. It helps in code review and can be applied separately.
> 
> Which patches ? They are all endpoint related:
>  (1) Core code
>  (2) test function driver

Till patch 6, that's why I inlined my reply at the 3rd point.

>  (3) rockchip rk3399 controller
> 
> (2) and (3) depend on the patches in (1), so splitting the series is a big
> possible only if (1) is applied first, so that is a source of delays and breaks
> the context of the patches...
> 

If you split patches 1-6 and post the rest of the Rockchip patches as a follow
up, it perfectly makes sense.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 03/18] PCI: endpoint: Introduce pci_epc_mem_map()/unmap()

[Manivannan Sadhasivam]

On Sat, Mar 30, 2024 at 01:19:13PM +0900, Damien Le Moal wrote:
> Introduce the function pci_epc_mem_map() to facilitate controller memory
> address allocation and mapping to a RC PCI address region in endpoint
> function drivers.
> 
> This function first uses pci_epc_map_align() to determine the controller
> memory address alignment (offset and size) constraints. The result of
> this function is used to allocate a controller physical memory region
> using pci_epc_mem_alloc_addr() and map it to the RC PCI address
> space with pci_epc_map_addr(). Since pci_epc_map_align() may indicate
> that a mapping can be smaller than the requested size, pci_epc_mem_map()
> may only partially map the RC PCI address region specified and return
> a smaller size for the effective mapping.
> 
> The counterpart of pci_epc_mem_map() to unmap and free the controller
> memory address region is pci_epc_mem_unmap().
> 
> Both functions operate using struct pci_epc_map data structure which is
> extended to contain the physical and virtual addresses of the allocated
> controller memory. Endpoint function drivers can use struct pci_epc_map
> to implement read/write accesses within the mapped RC PCI address region
> using the ->virt_addr and ->size fields.
> 
> This commit contains contributions from Rick Wertenbroek
> <rick.wertenbroek@gmail.com>.
> 

Adding 'Co-developed-by && Signed-off-by' tags would give the due credit.

> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>  drivers/pci/endpoint/pci-epc-core.c | 68 +++++++++++++++++++++++++++++
>  include/linux/pci-epc.h             |  6 +++
>  2 files changed, 74 insertions(+)
> 
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 37758ca91d7f..0095b54bdf9e 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -530,6 +530,74 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  }
>  EXPORT_SYMBOL_GPL(pci_epc_map_addr);
>  
> +/**
> + * pci_epc_mem_map() - allocate and map CPU address to PCI address

How about, 'pci_epc_alloc_map()'? I think the 'mem' prefix was added to the
existing APIs since the function definitions are in pci-epc-mem driver, but
not needed here.

> + * @epc: the EPC device on which the CPU address is to be allocated and mapped
> + * @func_no: the physical endpoint function number in the EPC device
> + * @vfunc_no: the virtual endpoint function number in the physical function
> + * @pci_addr: PCI address to which the CPU address should be mapped
> + * @size: the number of bytes to map starting from @pci_addr
> + * @map: where to return the mapping information
> + *
> + * Allocate a controller physical address region and map it to a RC PCI address

"Allocate an EPC address space region..."

> + * region, taking into account the controller physical address mapping
> + * constraints (if any). Returns the effective size of the mapping, which may

Return value should be specified separately for Kdoc.

> + * be less than @size, or a negative error code in case of error.
> + */
> +ssize_t pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +			u64 pci_addr, size_t size, struct pci_epc_map *map)
> +{
> +	int ret;
> +
> +	ret = pci_epc_map_align(epc, func_no, vfunc_no, pci_addr, size, map);
> +	if (ret)
> +		return ret;
> +
> +	map->virt_base = pci_epc_mem_alloc_addr(epc, &map->phys_base,
> +						map->map_size);

It'd be nice to move pci_epc_map_align() inside the existing
pci_epc_mem_alloc_addr() API to make sure that the allocated memory follows the
constraints of the EPC.

Would that make sense?

- Mani

> +	if (!map->virt_base)
> +		return -ENOMEM;
> +
> +	map->phys_addr = map->phys_base + map->map_ofst;
> +	map->virt_addr = map->virt_base + map->map_ofst;
> +
> +	ret = pci_epc_map_addr(epc, func_no, vfunc_no, map->phys_base,
> +			       map->map_pci_addr, map->map_size);
> +	if (ret) {
> +		pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
> +				      map->map_size);
> +		return ret;
> +	}
> +
> +	return map->pci_size;
> +}
> +EXPORT_SYMBOL_GPL(pci_epc_mem_map);
> +
> +/**
> + * pci_epc_mem_unmap() - unmap from PCI address and free a CPU address region
> + * @epc: the EPC device on which the CPU address is allocated and mapped
> + * @func_no: the physical endpoint function number in the EPC device
> + * @vfunc_no: the virtual endpoint function number in the physical function
> + * @map: the mapping information
> + *
> + * Allocate and map local CPU address to a PCI address, accounting for the
> + * controller local CPU address alignment constraints.
> + */
> +void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		       struct pci_epc_map *map)
> +{
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
> +		return;
> +
> +	if (!map || !map->pci_size)
> +		return;
> +
> +	pci_epc_unmap_addr(epc, func_no, vfunc_no, map->phys_base);
> +	pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
> +			      map->map_size);
> +}
> +EXPORT_SYMBOL_GPL(pci_epc_mem_unmap);
> +
>  /**
>   * pci_epc_clear_bar() - reset the BAR
>   * @epc: the EPC device for which the BAR has to be cleared
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index 8cfb4aaf2628..86397a500b54 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -304,4 +304,10 @@ void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
>  				     phys_addr_t *phys_addr, size_t size);
>  void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
>  			   void __iomem *virt_addr, size_t size);
> +
> +ssize_t pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +			u64 pci_addr, size_t size, struct pci_epc_map *map);
> +void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		       struct pci_epc_map *map);
> +
>  #endif /* __LINUX_PCI_EPC_H */
> -- 
> 2.44.0
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 16/18] PCI: rockchip-ep: Improve link training

[Rick Wertenbroek]

On Sat, Mar 30, 2024 at 5:20 AM Damien Le Moal <dlemoal@kernel.org> wrote:
>
> The Rockchip rk339 technical reference manual describe the endpoint mode
> link training process clearly and states that:
>   Insure link training completion and success by observing link_st field
>   in PCIe Client BASIC_STATUS1 register change to 2'b11. If both side
>   support PCIe Gen2 speed, re-train can be Initiated by asserting the
>   Retrain Link field in Link Control and Status Register. The software
>   should insure the BASIC_STATUS0[negotiated_speed] changes to "1", that
>   indicates re-train to Gen2 successfully.
> This procedure is very similar to what is done for the root-port mode in
> rockchip_pcie_host_init_port().
>
> Implement this link training procedure for the endpoint mode as well.
> Given that the rk3399 SoC does not have an interrupt signaling link
> status changes, training is implemented as a delayed work which is
> rescheduled until the link training completes or the endpoint controller
> is stopped. The link training work is first scheduled in
> rockchip_pcie_ep_start() when the endpoint function is started. Link
> training completion is signaled to the function using pci_epc_linkup().
> Accordingly, the linkup_notifier field of the rockchip pci_epc_features
> structure is changed to true.
>
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>  drivers/pci/controller/pcie-rockchip-ep.c | 79 ++++++++++++++++++++++-
>  drivers/pci/controller/pcie-rockchip.h    | 11 ++++
>  2 files changed, 89 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
> index 2767e8f1771d..4006e7dee71a 100644
> --- a/drivers/pci/controller/pcie-rockchip-ep.c
> +++ b/drivers/pci/controller/pcie-rockchip-ep.c
> @@ -16,6 +16,8 @@
>  #include <linux/platform_device.h>
>  #include <linux/pci-epf.h>
>  #include <linux/sizes.h>
> +#include <linux/workqueue.h>
> +#include <linux/iopoll.h>
>
>  #include "pcie-rockchip.h"
>
> @@ -48,6 +50,7 @@ struct rockchip_pcie_ep {
>         u64                     irq_pci_addr;
>         u8                      irq_pci_fn;
>         u8                      irq_pending;
> +       struct delayed_work     link_training;
>  };
>
>  static void rockchip_pcie_clear_ep_ob_atu(struct rockchip_pcie *rockchip,
> @@ -467,6 +470,8 @@ static int rockchip_pcie_ep_start(struct pci_epc *epc)
>                             PCIE_CLIENT_CONF_ENABLE,
>                             PCIE_CLIENT_CONFIG);
>
> +       schedule_delayed_work(&ep->link_training, 0);
> +
>         return 0;
>  }
>
> @@ -475,6 +480,8 @@ static void rockchip_pcie_ep_stop(struct pci_epc *epc)
>         struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
>         struct rockchip_pcie *rockchip = &ep->rockchip;
>
> +       cancel_delayed_work_sync(&ep->link_training);
> +
>         /* Stop link training and disable configuration */
>         rockchip_pcie_write(rockchip,
>                             PCIE_CLIENT_CONF_DISABLE |
> @@ -482,8 +489,77 @@ static void rockchip_pcie_ep_stop(struct pci_epc *epc)
>                             PCIE_CLIENT_CONFIG);
>  }
>
> +static void rockchip_pcie_ep_retrain_link(struct rockchip_pcie *rockchip)
> +{
> +       u32 status;
> +
> +       status = rockchip_pcie_read(rockchip, PCIE_EP_CONFIG_LCS);
> +       status |= PCI_EXP_LNKCTL_RL;
> +       rockchip_pcie_write(rockchip, status, PCIE_EP_CONFIG_LCS);
> +}
> +
> +static bool rockchip_pcie_ep_link_up(struct rockchip_pcie *rockchip)
> +{
> +       u32 val = rockchip_pcie_read(rockchip, PCIE_CLIENT_BASIC_STATUS1);
> +
> +       return PCIE_LINK_UP(val);
> +}
> +
> +static void rockchip_pcie_ep_link_training(struct work_struct *work)
> +{
> +       struct rockchip_pcie_ep *ep =
> +               container_of(work, struct rockchip_pcie_ep, link_training.work);
> +       struct rockchip_pcie *rockchip = &ep->rockchip;
> +       struct device *dev = rockchip->dev;
> +       u32 val;
> +       int ret;
> +
> +       /* Enable Gen1 training and wait for its completion */
> +       ret = readl_poll_timeout(rockchip->apb_base + PCIE_CORE_CTRL,
> +                                val, PCIE_LINK_TRAINING_DONE(val), 50,
> +                                LINK_TRAIN_TIMEOUT);
> +       if (ret)
> +               goto again;
> +
> +       /* Make sure that the link is up */
> +       ret = readl_poll_timeout(rockchip->apb_base + PCIE_CLIENT_BASIC_STATUS1,
> +                                val, PCIE_LINK_UP(val), 50,
> +                                LINK_TRAIN_TIMEOUT);
> +       if (ret)
> +               goto again;
> +
> +       /* Check the current speed */
> +       val = rockchip_pcie_read(rockchip, PCIE_CORE_CTRL);
> +       if (!PCIE_LINK_IS_GEN2(val) && rockchip->link_gen == 2) {
> +               /* Enable retrain for gen2 */
> +               rockchip_pcie_ep_retrain_link(rockchip);
> +               readl_poll_timeout(rockchip->apb_base + PCIE_CORE_CTRL,
> +                                  val, PCIE_LINK_IS_GEN2(val), 50,
> +                                  LINK_TRAIN_TIMEOUT);
> +       }
> +
> +       /* Check again that the link is up */
> +       if (!rockchip_pcie_ep_link_up(rockchip))
> +               goto again;
> +
> +       val = rockchip_pcie_read(rockchip, PCIE_CLIENT_BASIC_STATUS0);
> +       dev_info(dev,
> +                "Link UP (Negociated speed: %sGT/s, width: x%lu)\n",
> +                (val & PCIE_CLIENT_NEG_LINK_SPEED) ? "5" : "2.5",
> +                ((val & PCIE_CLIENT_NEG_LINK_WIDTH_MASK) >>
> +                 PCIE_CLIENT_NEG_LINK_WIDTH_SHIFT) << 1);
> +

This does not print the correct link width for x1 :

# [   60.518339] rockchip-pcie-ep fd000000.pcie-ep: Link UP
(Negociated speed: 5GT/s, width: x0)

This is because :

((val & PCIE_CLIENT_NEG_LINK_WIDTH_MASK) >>
 PCIE_CLIENT_NEG_LINK_WIDTH_SHIFT) << 1
will print 0 if the link width is 1, because bits 7:6 are 0b00, and
0b00 << 1 is still 0. (0b00 => x0, 0b01 => x2, 0b10 => x4)

Therefore the formula should be :
1 << ((val & PCIE_CLIENT_NEG_LINK_WIDTH_MASK) >>
 PCIE_CLIENT_NEG_LINK_WIDTH_SHIFT)
This shows the correct link width for all cases (0b00 => x1, 0b01 =>
x2, 0b10 => x4).

Reference : RK3399 TRM V1.3 pages 768-769 PCIE_CLIENT_BASIC_STATUS0
register description


> +       /* Notify the function */
> +       pci_epc_linkup(ep->epc);
> +
> +       return;
> +
> +again:
> +       schedule_delayed_work(&ep->link_training, msecs_to_jiffies(5));
> +}
> +
>  static const struct pci_epc_features rockchip_pcie_epc_features = {
> -       .linkup_notifier = false,
> +       .linkup_notifier = true,
>         .msi_capable = true,
>         .msix_capable = false,
>         .align = ROCKCHIP_PCIE_AT_SIZE_ALIGN,
> @@ -644,6 +720,7 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
>         rockchip = &ep->rockchip;
>         rockchip->is_rc = false;
>         rockchip->dev = dev;
> +       INIT_DELAYED_WORK(&ep->link_training, rockchip_pcie_ep_link_training);
>
>         epc = devm_pci_epc_create(dev, &rockchip_pcie_epc_ops);
>         if (IS_ERR(epc)) {
> diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h
> index 0263f158ee8d..3963b7097a91 100644
> --- a/drivers/pci/controller/pcie-rockchip.h
> +++ b/drivers/pci/controller/pcie-rockchip.h
> @@ -26,6 +26,7 @@
>  #define MAX_LANE_NUM                   4
>  #define MAX_REGION_LIMIT               32
>  #define MIN_EP_APERTURE                        28
> +#define LINK_TRAIN_TIMEOUT             (5000 * USEC_PER_MSEC)
>
>  #define PCIE_CLIENT_BASE               0x0
>  #define PCIE_CLIENT_CONFIG             (PCIE_CLIENT_BASE + 0x00)
> @@ -50,6 +51,10 @@
>  #define   PCIE_CLIENT_DEBUG_LTSSM_MASK         GENMASK(5, 0)
>  #define   PCIE_CLIENT_DEBUG_LTSSM_L1           0x18
>  #define   PCIE_CLIENT_DEBUG_LTSSM_L2           0x19
> +#define PCIE_CLIENT_BASIC_STATUS0      (PCIE_CLIENT_BASE + 0x44)
> +#define   PCIE_CLIENT_NEG_LINK_WIDTH_MASK      GENMASK(7, 6)
> +#define   PCIE_CLIENT_NEG_LINK_WIDTH_SHIFT     6
> +#define   PCIE_CLIENT_NEG_LINK_SPEED           BIT(5)
>  #define PCIE_CLIENT_BASIC_STATUS1      (PCIE_CLIENT_BASE + 0x48)
>  #define   PCIE_CLIENT_LINK_STATUS_UP           0x00300000
>  #define   PCIE_CLIENT_LINK_STATUS_MASK         0x00300000
> @@ -87,6 +92,8 @@
>
>  #define PCIE_CORE_CTRL_MGMT_BASE       0x900000
>  #define PCIE_CORE_CTRL                 (PCIE_CORE_CTRL_MGMT_BASE + 0x000)
> +#define   PCIE_CORE_PL_CONF_LS_MASK            0x00000001
> +#define   PCIE_CORE_PL_CONF_LS_READY           0x00000001
>  #define   PCIE_CORE_PL_CONF_SPEED_5G           0x00000008
>  #define   PCIE_CORE_PL_CONF_SPEED_MASK         0x00000018
>  #define   PCIE_CORE_PL_CONF_LANE_MASK          0x00000006
> @@ -144,6 +151,7 @@
>  #define PCIE_RC_CONFIG_BASE            0xa00000
>  #define PCIE_EP_CONFIG_BASE            0xa00000
>  #define PCIE_EP_CONFIG_DID_VID         (PCIE_EP_CONFIG_BASE + 0x00)
> +#define PCIE_EP_CONFIG_LCS             (PCIE_EP_CONFIG_BASE + 0xd0)
>  #define PCIE_RC_CONFIG_RID_CCR         (PCIE_RC_CONFIG_BASE + 0x08)
>  #define PCIE_RC_CONFIG_DCR             (PCIE_RC_CONFIG_BASE + 0xc4)
>  #define   PCIE_RC_CONFIG_DCR_CSPL_SHIFT                18
> @@ -155,6 +163,7 @@
>  #define PCIE_RC_CONFIG_LINK_CAP                (PCIE_RC_CONFIG_BASE + 0xcc)
>  #define   PCIE_RC_CONFIG_LINK_CAP_L0S          BIT(10)
>  #define PCIE_RC_CONFIG_LCS             (PCIE_RC_CONFIG_BASE + 0xd0)
> +#define PCIE_EP_CONFIG_LCS             (PCIE_EP_CONFIG_BASE + 0xd0)
>  #define PCIE_RC_CONFIG_L1_SUBSTATE_CTRL2 (PCIE_RC_CONFIG_BASE + 0x90c)
>  #define PCIE_RC_CONFIG_THP_CAP         (PCIE_RC_CONFIG_BASE + 0x274)
>  #define   PCIE_RC_CONFIG_THP_CAP_NEXT_MASK     GENMASK(31, 20)
> @@ -192,6 +201,8 @@
>  #define ROCKCHIP_VENDOR_ID                     0x1d87
>  #define PCIE_LINK_IS_L2(x) \
>         (((x) & PCIE_CLIENT_DEBUG_LTSSM_MASK) == PCIE_CLIENT_DEBUG_LTSSM_L2)
> +#define PCIE_LINK_TRAINING_DONE(x) \
> +       (((x) & PCIE_CORE_PL_CONF_LS_MASK) == PCIE_CORE_PL_CONF_LS_READY)
>  #define PCIE_LINK_UP(x) \
>         (((x) & PCIE_CLIENT_LINK_STATUS_MASK) == PCIE_CLIENT_LINK_STATUS_UP)
>  #define PCIE_LINK_IS_GEN2(x) \
> --
> 2.44.0
>

Tested-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>

Best regards,
Rick

Re: [PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()

[Kishon Vijay Abraham I]

Hi Damien,

On 3/30/2024 9:49 AM, Damien Le Moal wrote:
> Some endpoint controllers have requirements on the alignment of the
> controller physical memory address that must be used to map a RC PCI
> address region. For instance, the rockchip endpoint controller uses
> at most the lower 20 bits of a physical memory address region as the
> lower bits of an RC PCI address. For mapping a PCI address region of
> size bytes starting from pci_addr, the exact number of address bits
> used is the number of address bits changing in the address range
> [pci_addr..pci_addr + size - 1].
> 
> For this example, this creates the following constraints:
> 1) The offset into the controller physical memory allocated for a
>     mapping depends on the mapping size *and* the starting PCI address
>     for the mapping.
> 2) A mapping size cannot exceed the controller windows size (1MB) minus
>     the offset needed into the allocated physical memory, which can end
>     up being a smaller size than the desired mapping size.
> 
> Handling these constraints independently of the controller being used in
> a PCI EP function driver is not possible with the current EPC API as
> it only provides the ->align field in struct pci_epc_features.
> Furthermore, this alignment is static and does not depend on a mapping
> pci address and size.
> 
> Solve this by introducing the function pci_epc_map_align() and the
> endpoint controller operation ->map_align to allow endpoint function
> drivers to obtain the size and the offset into a controller address
> region that must be used to map an RC PCI address region. The size
> of the physical address region provided by pci_epc_map_align() can then
> be used as the size argument for the function pci_epc_mem_alloc_addr().
> The offset into the allocated controller memory can be used to
> correctly handle data transfers. Of note is that pci_epc_map_align() may
> indicate upon return a mapping size that is smaller (but not 0) than the
> requested PCI address region size. For such case, an endpoint function
> driver must handle data transfers in fragments.
> 
> The controller operation ->map_align is optional: controllers that do
> not have any address alignment constraints for mapping a RC PCI address
> region do not need to implement this operation. For such controllers,
> pci_epc_map_align() always returns the mapping size as equal
> to the requested size and an offset equal to 0.
> 
> The structure pci_epc_map is introduced to represent a mapping start PCI
> address, size and the size and offset into the controller memory needed
> for mapping the PCI address region.
> 
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>   drivers/pci/endpoint/pci-epc-core.c | 66 +++++++++++++++++++++++++++++
>   include/linux/pci-epc.h             | 33 +++++++++++++++
>   2 files changed, 99 insertions(+)
> 
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 754afd115bbd..37758ca91d7f 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -433,6 +433,72 @@ void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>   }
>   EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
>   
> +/**
> + * pci_epc_map_align() - Get the offset into and the size of a controller memory
> + *			 address region needed to map a RC PCI address region
> + * @epc: the EPC device on which address is allocated
> + * @func_no: the physical endpoint function number in the EPC device
> + * @vfunc_no: the virtual endpoint function number in the physical function
> + * @pci_addr: PCI address to which the physical address should be mapped
> + * @size: the size of the mapping starting from @pci_addr
> + * @map: populate here the actual size and offset into the controller memory
> + *       that must be allocated for the mapping
> + *
> + * Invoke the controller map_align operation to obtain the size and the offset
> + * into a controller address region that must be allocated to map @size
> + * bytes of the RC PCI address space starting from @pci_addr.
> + *
> + * The size of the mapping that can be handled by the controller is indicated
> + * using the pci_size field of @map. This size may be smaller than the requested
> + * @size. In such case, the function driver must handle the mapping using
> + * several fragments. The offset into the controller memory for the effective
> + * mapping of the @pci_addr..@pci_addr+@map->pci_size address range is indicated
> + * using the map_ofst field of @map.
> + */
> +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		      u64 pci_addr, size_t size, struct pci_epc_map *map)
> +{
> +	const struct pci_epc_features *features;
> +	size_t mask;
> +	int ret;
> +
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
> +		return -EINVAL;
> +
> +	if (!size || !map)
> +		return -EINVAL;
> +
> +	memset(map, 0, sizeof(*map));
> +	map->pci_addr = pci_addr;
> +	map->pci_size = size;
> +
> +	if (epc->ops->map_align) {
> +		mutex_lock(&epc->lock);
> +		ret = epc->ops->map_align(epc, func_no, vfunc_no, map);
> +		mutex_unlock(&epc->lock);
> +		return ret;
> +	}
> +
> +	/*
> +	 * Assume a fixed alignment constraint as specified by the controller
> +	 * features.
> +	 */
> +	features = pci_epc_get_features(epc, func_no, vfunc_no);
> +	if (!features || !features->align) {
> +		map->map_pci_addr = pci_addr;
> +		map->map_size = size;
> +		map->map_ofst = 0;
> +	}

The 'align' of pci_epc_features was initially added only to address the 
inbound ATU constraints. This is also added as comment in [1]. The PCI 
address restrictions (only fixed alignment constraint) were handled by 
the host side driver and depends on the connected endpoint device 
(atleast it was like that for pci_endpoint_test.c [2]).
So pci-epf-test.c used the 'align' in pci_epc_features only as part of 
pci_epf_alloc_space().

Though I have abused 'align' of pci_epc_features in pci-epf-ntb.c using 
it out of pci_epf_alloc_space(), I think we should keep the 'align' of 
pci_epc_features only within pci_epf_alloc_space() and controllers with 
any PCI address restrictions to implement ->map_align(). This could as 
well be done in a phased manner to let controllers implement 
->map_align() and then remove using  pci_epc_features in 
pci_epc_map_align(). Let me know what you think?

Thanks,
Kishon

[1] -> 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/pci-epc.h?h=v6.9-rc2#n187

[2] -> 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/misc/pci_endpoint_test.c?h=v6.9-rc2#n127
> +
> +	mask = features->align - 1;
> +	map->map_pci_addr = map->pci_addr & ~mask;
> +	map->map_ofst = map->pci_addr & mask;
> +	map->map_size = ALIGN(map->map_ofst + map->pci_size, features->align);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(pci_epc_map_align);
> +
>   /**
>    * pci_epc_map_addr() - map CPU address to PCI address
>    * @epc: the EPC device on which address is allocated
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index cc2f70d061c8..8cfb4aaf2628 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -32,11 +32,40 @@ pci_epc_interface_string(enum pci_epc_interface_type type)
>   	}
>   }
>   
> +/**
> + * struct pci_epc_map - information about EPC memory for mapping a RC PCI
> + *                      address range
> + * @pci_addr: start address of the RC PCI address range to map
> + * @pci_size: size of the RC PCI address range to map
> + * @map_pci_addr: RC PCI address used as the first address mapped
> + * @map_size: size of the controller memory needed for the mapping
> + * @map_ofst: offset into the controller memory needed for the mapping
> + * @phys_base: base physical address of the allocated EPC memory
> + * @phys_addr: physical address at which @pci_addr is mapped
> + * @virt_base: base virtual address of the allocated EPC memory
> + * @virt_addr: virtual address at which @pci_addr is mapped
> + */
> +struct pci_epc_map {
> +	phys_addr_t	pci_addr;
> +	size_t		pci_size;
> +
> +	phys_addr_t	map_pci_addr;
> +	size_t		map_size;
> +	phys_addr_t	map_ofst;
> +
> +	phys_addr_t	phys_base;
> +	phys_addr_t	phys_addr;
> +	void __iomem	*virt_base;
> +	void __iomem	*virt_addr;
> +};
> +
>   /**
>    * struct pci_epc_ops - set of function pointers for performing EPC operations
>    * @write_header: ops to populate configuration space header
>    * @set_bar: ops to configure the BAR
>    * @clear_bar: ops to reset the BAR
> + * @map_align: operation to get the size and offset into a controller memory
> + *             window needed to map an RC PCI address region
>    * @map_addr: ops to map CPU address to PCI address
>    * @unmap_addr: ops to unmap CPU address and PCI address
>    * @set_msi: ops to set the requested number of MSI interrupts in the MSI
> @@ -61,6 +90,8 @@ struct pci_epc_ops {
>   			   struct pci_epf_bar *epf_bar);
>   	void	(*clear_bar)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>   			     struct pci_epf_bar *epf_bar);
> +	int	(*map_align)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +			    struct pci_epc_map *map);
>   	int	(*map_addr)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>   			    phys_addr_t addr, u64 pci_addr, size_t size);
>   	void	(*unmap_addr)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> @@ -234,6 +265,8 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>   		    struct pci_epf_bar *epf_bar);
>   void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>   		       struct pci_epf_bar *epf_bar);
> +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		      u64 pci_addr, size_t size, struct pci_epc_map *map);
>   int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>   		     phys_addr_t phys_addr,
>   		     u64 pci_addr, size_t size);

Re: [PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()

[Damien Le Moal]

On 4/3/24 21:33, Kishon Vijay Abraham I wrote:
> Hi Damien,
> 
> On 3/30/2024 9:49 AM, Damien Le Moal wrote:
>> Some endpoint controllers have requirements on the alignment of the
>> controller physical memory address that must be used to map a RC PCI
>> address region. For instance, the rockchip endpoint controller uses
>> at most the lower 20 bits of a physical memory address region as the
>> lower bits of an RC PCI address. For mapping a PCI address region of
>> size bytes starting from pci_addr, the exact number of address bits
>> used is the number of address bits changing in the address range
>> [pci_addr..pci_addr + size - 1].
>>
>> For this example, this creates the following constraints:
>> 1) The offset into the controller physical memory allocated for a
>>     mapping depends on the mapping size *and* the starting PCI address
>>     for the mapping.
>> 2) A mapping size cannot exceed the controller windows size (1MB) minus
>>     the offset needed into the allocated physical memory, which can end
>>     up being a smaller size than the desired mapping size.
>>
>> Handling these constraints independently of the controller being used in
>> a PCI EP function driver is not possible with the current EPC API as
>> it only provides the ->align field in struct pci_epc_features.
>> Furthermore, this alignment is static and does not depend on a mapping
>> pci address and size.
>>
>> Solve this by introducing the function pci_epc_map_align() and the
>> endpoint controller operation ->map_align to allow endpoint function
>> drivers to obtain the size and the offset into a controller address
>> region that must be used to map an RC PCI address region. The size
>> of the physical address region provided by pci_epc_map_align() can then
>> be used as the size argument for the function pci_epc_mem_alloc_addr().
>> The offset into the allocated controller memory can be used to
>> correctly handle data transfers. Of note is that pci_epc_map_align() may
>> indicate upon return a mapping size that is smaller (but not 0) than the
>> requested PCI address region size. For such case, an endpoint function
>> driver must handle data transfers in fragments.
>>
>> The controller operation ->map_align is optional: controllers that do
>> not have any address alignment constraints for mapping a RC PCI address
>> region do not need to implement this operation. For such controllers,
>> pci_epc_map_align() always returns the mapping size as equal
>> to the requested size and an offset equal to 0.
>>
>> The structure pci_epc_map is introduced to represent a mapping start PCI
>> address, size and the size and offset into the controller memory needed
>> for mapping the PCI address region.
>>
>> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
>> ---
>>   drivers/pci/endpoint/pci-epc-core.c | 66 +++++++++++++++++++++++++++++
>>   include/linux/pci-epc.h             | 33 +++++++++++++++
>>   2 files changed, 99 insertions(+)
>>
>> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
>> index 754afd115bbd..37758ca91d7f 100644
>> --- a/drivers/pci/endpoint/pci-epc-core.c
>> +++ b/drivers/pci/endpoint/pci-epc-core.c
>> @@ -433,6 +433,72 @@ void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>>   }
>>   EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
>>   
>> +/**
>> + * pci_epc_map_align() - Get the offset into and the size of a controller memory
>> + *			 address region needed to map a RC PCI address region
>> + * @epc: the EPC device on which address is allocated
>> + * @func_no: the physical endpoint function number in the EPC device
>> + * @vfunc_no: the virtual endpoint function number in the physical function
>> + * @pci_addr: PCI address to which the physical address should be mapped
>> + * @size: the size of the mapping starting from @pci_addr
>> + * @map: populate here the actual size and offset into the controller memory
>> + *       that must be allocated for the mapping
>> + *
>> + * Invoke the controller map_align operation to obtain the size and the offset
>> + * into a controller address region that must be allocated to map @size
>> + * bytes of the RC PCI address space starting from @pci_addr.
>> + *
>> + * The size of the mapping that can be handled by the controller is indicated
>> + * using the pci_size field of @map. This size may be smaller than the requested
>> + * @size. In such case, the function driver must handle the mapping using
>> + * several fragments. The offset into the controller memory for the effective
>> + * mapping of the @pci_addr..@pci_addr+@map->pci_size address range is indicated
>> + * using the map_ofst field of @map.
>> + */
>> +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>> +		      u64 pci_addr, size_t size, struct pci_epc_map *map)
>> +{
>> +	const struct pci_epc_features *features;
>> +	size_t mask;
>> +	int ret;
>> +
>> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>> +		return -EINVAL;
>> +
>> +	if (!size || !map)
>> +		return -EINVAL;
>> +
>> +	memset(map, 0, sizeof(*map));
>> +	map->pci_addr = pci_addr;
>> +	map->pci_size = size;
>> +
>> +	if (epc->ops->map_align) {
>> +		mutex_lock(&epc->lock);
>> +		ret = epc->ops->map_align(epc, func_no, vfunc_no, map);
>> +		mutex_unlock(&epc->lock);
>> +		return ret;
>> +	}
>> +
>> +	/*
>> +	 * Assume a fixed alignment constraint as specified by the controller
>> +	 * features.
>> +	 */
>> +	features = pci_epc_get_features(epc, func_no, vfunc_no);
>> +	if (!features || !features->align) {
>> +		map->map_pci_addr = pci_addr;
>> +		map->map_size = size;
>> +		map->map_ofst = 0;
>> +	}
> 
> The 'align' of pci_epc_features was initially added only to address the 
> inbound ATU constraints. This is also added as comment in [1]. The PCI 
> address restrictions (only fixed alignment constraint) were handled by 
> the host side driver and depends on the connected endpoint device 
> (atleast it was like that for pci_endpoint_test.c [2]).
> So pci-epf-test.c used the 'align' in pci_epc_features only as part of 
> pci_epf_alloc_space().
> 
> Though I have abused 'align' of pci_epc_features in pci-epf-ntb.c using 
> it out of pci_epf_alloc_space(), I think we should keep the 'align' of 
> pci_epc_features only within pci_epf_alloc_space() and controllers with 
> any PCI address restrictions to implement ->map_align(). This could as 
> well be done in a phased manner to let controllers implement 
> ->map_align() and then remove using  pci_epc_features in 
> pci_epc_map_align(). Let me know what you think?

Yep, good idea. I will remove the use of "align" as a default alignment
constraint. For controllers that have a fixed alignment constraint (not
necessarilly epc->features->align), it is trivial to provide a generic helper
function that implements the ->map_align method.


-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()

[Dan Carpenter]

Hi Damien,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Damien-Le-Moal/PCI-endpoint-Introduce-pci_epc_function_is_valid/20240330-122311
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20240330041928.1555578-3-dlemoal%40kernel.org
patch subject: [PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()
config: parisc-randconfig-r071-20240405 (https://download.01.org/0day-ci/archive/20240405/202404051508.hvNRDVZq-lkp@intel.com/config)
compiler: hppa-linux-gcc (GCC) 13.2.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202404051508.hvNRDVZq-lkp@intel.com/

smatch warnings:
drivers/pci/endpoint/pci-epc-core.c:493 pci_epc_map_align() error: we previously assumed 'features' could be null (see line 487)

vim +/features +493 drivers/pci/endpoint/pci-epc-core.c

9d2f10d2ace040 Damien Le Moal         2024-03-30  458  int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
9d2f10d2ace040 Damien Le Moal         2024-03-30  459  		      u64 pci_addr, size_t size, struct pci_epc_map *map)
9d2f10d2ace040 Damien Le Moal         2024-03-30  460  {
9d2f10d2ace040 Damien Le Moal         2024-03-30  461  	const struct pci_epc_features *features;
9d2f10d2ace040 Damien Le Moal         2024-03-30  462  	size_t mask;
9d2f10d2ace040 Damien Le Moal         2024-03-30  463  	int ret;
9d2f10d2ace040 Damien Le Moal         2024-03-30  464  
9d2f10d2ace040 Damien Le Moal         2024-03-30  465  	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
9d2f10d2ace040 Damien Le Moal         2024-03-30  466  		return -EINVAL;
9d2f10d2ace040 Damien Le Moal         2024-03-30  467  
9d2f10d2ace040 Damien Le Moal         2024-03-30  468  	if (!size || !map)
9d2f10d2ace040 Damien Le Moal         2024-03-30  469  		return -EINVAL;
9d2f10d2ace040 Damien Le Moal         2024-03-30  470  
9d2f10d2ace040 Damien Le Moal         2024-03-30  471  	memset(map, 0, sizeof(*map));
9d2f10d2ace040 Damien Le Moal         2024-03-30  472  	map->pci_addr = pci_addr;
9d2f10d2ace040 Damien Le Moal         2024-03-30  473  	map->pci_size = size;
9d2f10d2ace040 Damien Le Moal         2024-03-30  474  
9d2f10d2ace040 Damien Le Moal         2024-03-30  475  	if (epc->ops->map_align) {
9d2f10d2ace040 Damien Le Moal         2024-03-30  476  		mutex_lock(&epc->lock);
9d2f10d2ace040 Damien Le Moal         2024-03-30  477  		ret = epc->ops->map_align(epc, func_no, vfunc_no, map);
9d2f10d2ace040 Damien Le Moal         2024-03-30  478  		mutex_unlock(&epc->lock);
9d2f10d2ace040 Damien Le Moal         2024-03-30  479  		return ret;
9d2f10d2ace040 Damien Le Moal         2024-03-30  480  	}
9d2f10d2ace040 Damien Le Moal         2024-03-30  481  
9d2f10d2ace040 Damien Le Moal         2024-03-30  482  	/*
9d2f10d2ace040 Damien Le Moal         2024-03-30  483  	 * Assume a fixed alignment constraint as specified by the controller
9d2f10d2ace040 Damien Le Moal         2024-03-30  484  	 * features.
9d2f10d2ace040 Damien Le Moal         2024-03-30  485  	 */
9d2f10d2ace040 Damien Le Moal         2024-03-30  486  	features = pci_epc_get_features(epc, func_no, vfunc_no);
9d2f10d2ace040 Damien Le Moal         2024-03-30 @487  	if (!features || !features->align) {
                                                            ^^^^^^^^^
Check for NULL

9d2f10d2ace040 Damien Le Moal         2024-03-30  488  		map->map_pci_addr = pci_addr;
9d2f10d2ace040 Damien Le Moal         2024-03-30  489  		map->map_size = size;
9d2f10d2ace040 Damien Le Moal         2024-03-30  490  		map->map_ofst = 0;

Missing return 0?

9d2f10d2ace040 Damien Le Moal         2024-03-30  491  	}
9d2f10d2ace040 Damien Le Moal         2024-03-30  492  
9d2f10d2ace040 Damien Le Moal         2024-03-30 @493  	mask = features->align - 1;
                                                               ^^^^^^^^^^

9d2f10d2ace040 Damien Le Moal         2024-03-30  494  	map->map_pci_addr = map->pci_addr & ~mask;
9d2f10d2ace040 Damien Le Moal         2024-03-30  495  	map->map_ofst = map->pci_addr & mask;
9d2f10d2ace040 Damien Le Moal         2024-03-30  496  	map->map_size = ALIGN(map->map_ofst + map->pci_size, features->align);
9d2f10d2ace040 Damien Le Moal         2024-03-30  497  
9d2f10d2ace040 Damien Le Moal         2024-03-30  498  	return 0;
9d2f10d2ace040 Damien Le Moal         2024-03-30  499  }

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()

[Niklas Cassel]

On Thu, Apr 04, 2024 at 11:43:47AM +0900, Damien Le Moal wrote:
> On 4/3/24 21:33, Kishon Vijay Abraham I wrote:
> > Hi Damien,
> > 
> > On 3/30/2024 9:49 AM, Damien Le Moal wrote:
> >> Some endpoint controllers have requirements on the alignment of the
> >> controller physical memory address that must be used to map a RC PCI
> >> address region. For instance, the rockchip endpoint controller uses
> >> at most the lower 20 bits of a physical memory address region as the
> >> lower bits of an RC PCI address. For mapping a PCI address region of
> >> size bytes starting from pci_addr, the exact number of address bits
> >> used is the number of address bits changing in the address range
> >> [pci_addr..pci_addr + size - 1].
> >>
> >> For this example, this creates the following constraints:
> >> 1) The offset into the controller physical memory allocated for a
> >>     mapping depends on the mapping size *and* the starting PCI address
> >>     for the mapping.
> >> 2) A mapping size cannot exceed the controller windows size (1MB) minus
> >>     the offset needed into the allocated physical memory, which can end
> >>     up being a smaller size than the desired mapping size.
> >>
> >> Handling these constraints independently of the controller being used in
> >> a PCI EP function driver is not possible with the current EPC API as
> >> it only provides the ->align field in struct pci_epc_features.
> >> Furthermore, this alignment is static and does not depend on a mapping
> >> pci address and size.
> >>
> >> Solve this by introducing the function pci_epc_map_align() and the
> >> endpoint controller operation ->map_align to allow endpoint function
> >> drivers to obtain the size and the offset into a controller address
> >> region that must be used to map an RC PCI address region. The size
> >> of the physical address region provided by pci_epc_map_align() can then
> >> be used as the size argument for the function pci_epc_mem_alloc_addr().
> >> The offset into the allocated controller memory can be used to
> >> correctly handle data transfers. Of note is that pci_epc_map_align() may
> >> indicate upon return a mapping size that is smaller (but not 0) than the
> >> requested PCI address region size. For such case, an endpoint function
> >> driver must handle data transfers in fragments.
> >>
> >> The controller operation ->map_align is optional: controllers that do
> >> not have any address alignment constraints for mapping a RC PCI address
> >> region do not need to implement this operation. For such controllers,
> >> pci_epc_map_align() always returns the mapping size as equal
> >> to the requested size and an offset equal to 0.
> >>
> >> The structure pci_epc_map is introduced to represent a mapping start PCI
> >> address, size and the size and offset into the controller memory needed
> >> for mapping the PCI address region.
> >>
> >> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> >> ---
> >>   drivers/pci/endpoint/pci-epc-core.c | 66 +++++++++++++++++++++++++++++
> >>   include/linux/pci-epc.h             | 33 +++++++++++++++
> >>   2 files changed, 99 insertions(+)
> >>
> >> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> >> index 754afd115bbd..37758ca91d7f 100644
> >> --- a/drivers/pci/endpoint/pci-epc-core.c
> >> +++ b/drivers/pci/endpoint/pci-epc-core.c
> >> @@ -433,6 +433,72 @@ void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> >>   }
> >>   EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
> >>   
> >> +/**
> >> + * pci_epc_map_align() - Get the offset into and the size of a controller memory
> >> + *			 address region needed to map a RC PCI address region
> >> + * @epc: the EPC device on which address is allocated
> >> + * @func_no: the physical endpoint function number in the EPC device
> >> + * @vfunc_no: the virtual endpoint function number in the physical function
> >> + * @pci_addr: PCI address to which the physical address should be mapped
> >> + * @size: the size of the mapping starting from @pci_addr
> >> + * @map: populate here the actual size and offset into the controller memory
> >> + *       that must be allocated for the mapping
> >> + *
> >> + * Invoke the controller map_align operation to obtain the size and the offset
> >> + * into a controller address region that must be allocated to map @size
> >> + * bytes of the RC PCI address space starting from @pci_addr.
> >> + *
> >> + * The size of the mapping that can be handled by the controller is indicated
> >> + * using the pci_size field of @map. This size may be smaller than the requested
> >> + * @size. In such case, the function driver must handle the mapping using
> >> + * several fragments. The offset into the controller memory for the effective
> >> + * mapping of the @pci_addr..@pci_addr+@map->pci_size address range is indicated
> >> + * using the map_ofst field of @map.
> >> + */
> >> +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> >> +		      u64 pci_addr, size_t size, struct pci_epc_map *map)
> >> +{
> >> +	const struct pci_epc_features *features;
> >> +	size_t mask;
> >> +	int ret;
> >> +
> >> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
> >> +		return -EINVAL;
> >> +
> >> +	if (!size || !map)
> >> +		return -EINVAL;
> >> +
> >> +	memset(map, 0, sizeof(*map));
> >> +	map->pci_addr = pci_addr;
> >> +	map->pci_size = size;
> >> +
> >> +	if (epc->ops->map_align) {
> >> +		mutex_lock(&epc->lock);
> >> +		ret = epc->ops->map_align(epc, func_no, vfunc_no, map);
> >> +		mutex_unlock(&epc->lock);
> >> +		return ret;
> >> +	}
> >> +
> >> +	/*
> >> +	 * Assume a fixed alignment constraint as specified by the controller
> >> +	 * features.
> >> +	 */
> >> +	features = pci_epc_get_features(epc, func_no, vfunc_no);
> >> +	if (!features || !features->align) {
> >> +		map->map_pci_addr = pci_addr;
> >> +		map->map_size = size;
> >> +		map->map_ofst = 0;
> >> +	}
> > 
> > The 'align' of pci_epc_features was initially added only to address the 
> > inbound ATU constraints. This is also added as comment in [1]. The PCI 
> > address restrictions (only fixed alignment constraint) were handled by 
> > the host side driver and depends on the connected endpoint device 
> > (atleast it was like that for pci_endpoint_test.c [2]).
> > So pci-epf-test.c used the 'align' in pci_epc_features only as part of 
> > pci_epf_alloc_space().
> > 
> > Though I have abused 'align' of pci_epc_features in pci-epf-ntb.c using 
> > it out of pci_epf_alloc_space(), I think we should keep the 'align' of 
> > pci_epc_features only within pci_epf_alloc_space() and controllers with 
> > any PCI address restrictions to implement ->map_align(). This could as 
> > well be done in a phased manner to let controllers implement 
> > ->map_align() and then remove using  pci_epc_features in 
> > pci_epc_map_align(). Let me know what you think?

First you say that you want to avoid using epc_features->align inside
pci_epc_map_align(), and then you say that we could do it in phases,
and eventually stop using epc_features->align in pci_epc_map_align().

I'm confused... :)

Do you really want pci_epc_map_align() to make use of epc_features->align ?

Don't you mean ep->page_size ?
(Please read the whole email to see my reasoning.)


> 
> Yep, good idea. I will remove the use of "align" as a default alignment
> constraint. For controllers that have a fixed alignment constraint (not
> necessarilly epc->features->align), it is trivial to provide a generic helper
> function that implements the ->map_align method.

We can see that commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2a9a801620efac92885fc9cd53594c0b9aba87a4

Introduced epc_features->align and modified pci_epf_alloc_space() to use it.

From reading the commit, it appears that epc_features->align was intended to
represent inbound iATU alignment requirement.

For DWC based controllers, the inbound iATU address must be aligned to:
CX_ATU_MIN_REGION_SIZE.

AFAICT, epc_features->align currently has nothing to do with traffic outbound
from the EP.


For aligning the reads/writes to buffers allocated on the host side,
we currently have .alignment in the host side driver:
https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/misc/pci_endpoint_test.c#L966-L1021

Which should be set to the outbound iATU alignment requirement.

For DWC based controllers, the outbound iATU address must be aligned to:
CX_ATU_MIN_REGION_SIZE.


Additionally, we have ep->page_size, which defines the smallest outbound unit
that can be mapped.
(On DWC based controllers, tis is CX_ATU_MIN_REGION_SIZE.)

ep->page_size is used to specify the outbound alignment for e.g.
dw_pcie_ep_raise_msi_irq() and dw_pcie_ep_raise_msix_irq():
https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/pci/controller/dwc/pcie-designware-ep.c#L488
https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/pci/controller/dwc/pcie-designware-ep.c#L555

which makes sure that we can write to the RC side MSI/MSI-X address
while satisfying the outbound iATU alignment requirement.

See also:
https://lore.kernel.org/linux-pci/20240402-pci2_upstream-v3-2-803414bdb430@nxp.com/



Now I understand that rockchip is the first one that does not have a fixed
alignment.
So for that platform, map_align() will be different from ep->page_size.
(For all DWC based drivers the outbound iATU alignment requirement is
the same as the page size.)

However, it would be nice if:
1) We could have a default implementation of map_align() that by default uses
ep->page_size. Platforms that have non-fixed alignment requirements could
define their own map_align().

2) We fix dw_pcie_ep_raise_msi_irq() and dw_pcie_ep_raise_msix_irq() to use
the new pci_epc_map_align().

3) It is getting too complicated with all these...
epc_features->align, ep->page_size, map_align(), and .alignment in host driver.
I think that we need to document each of these in Documentation/PCI/endpoint/

4) It would be nice if we could set page_size correctly for all the PCI device
and vendor IDs that have defined an .alignment in drivers/misc/pci_endpoint_test.c
in the correct EPC driver. That way, we should be able to completely remove all
.alignment specified in drivers/misc/pci_endpoint_test.c.

5) Unfortunately drivers/misc/pci_endpoint_test.c defines a default alignment
of 4K:
https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/misc/pci_endpoint_test.c#L968
https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/misc/pci_endpoint_test.c#L820

It would be nice if we could get rid of this as well. Or perhaps add an option
to pci_test so that it does not use this 4k alignment, such that we can verify
that pci_epc_map_align() is actually working.



In my opinion 4) is the biggest win with this series, because it means that
we define the alignment in the EPC driver, instead of needing to define it in
each and every host side driver. But right now, this great improvement is not
really visible for someone looking quickly at the current series.


Kind regards,
Niklas

Re: [PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()

[Damien Le Moal]

On 4/5/24 21:20, Niklas Cassel wrote:
> On Thu, Apr 04, 2024 at 11:43:47AM +0900, Damien Le Moal wrote:
>> On 4/3/24 21:33, Kishon Vijay Abraham I wrote:
>>> Hi Damien,
>>>
>>> On 3/30/2024 9:49 AM, Damien Le Moal wrote:
>>>> Some endpoint controllers have requirements on the alignment of the
>>>> controller physical memory address that must be used to map a RC PCI
>>>> address region. For instance, the rockchip endpoint controller uses
>>>> at most the lower 20 bits of a physical memory address region as the
>>>> lower bits of an RC PCI address. For mapping a PCI address region of
>>>> size bytes starting from pci_addr, the exact number of address bits
>>>> used is the number of address bits changing in the address range
>>>> [pci_addr..pci_addr + size - 1].
>>>>
>>>> For this example, this creates the following constraints:
>>>> 1) The offset into the controller physical memory allocated for a
>>>>     mapping depends on the mapping size *and* the starting PCI address
>>>>     for the mapping.
>>>> 2) A mapping size cannot exceed the controller windows size (1MB) minus
>>>>     the offset needed into the allocated physical memory, which can end
>>>>     up being a smaller size than the desired mapping size.
>>>>
>>>> Handling these constraints independently of the controller being used in
>>>> a PCI EP function driver is not possible with the current EPC API as
>>>> it only provides the ->align field in struct pci_epc_features.
>>>> Furthermore, this alignment is static and does not depend on a mapping
>>>> pci address and size.
>>>>
>>>> Solve this by introducing the function pci_epc_map_align() and the
>>>> endpoint controller operation ->map_align to allow endpoint function
>>>> drivers to obtain the size and the offset into a controller address
>>>> region that must be used to map an RC PCI address region. The size
>>>> of the physical address region provided by pci_epc_map_align() can then
>>>> be used as the size argument for the function pci_epc_mem_alloc_addr().
>>>> The offset into the allocated controller memory can be used to
>>>> correctly handle data transfers. Of note is that pci_epc_map_align() may
>>>> indicate upon return a mapping size that is smaller (but not 0) than the
>>>> requested PCI address region size. For such case, an endpoint function
>>>> driver must handle data transfers in fragments.
>>>>
>>>> The controller operation ->map_align is optional: controllers that do
>>>> not have any address alignment constraints for mapping a RC PCI address
>>>> region do not need to implement this operation. For such controllers,
>>>> pci_epc_map_align() always returns the mapping size as equal
>>>> to the requested size and an offset equal to 0.
>>>>
>>>> The structure pci_epc_map is introduced to represent a mapping start PCI
>>>> address, size and the size and offset into the controller memory needed
>>>> for mapping the PCI address region.
>>>>
>>>> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
>>>> ---
>>>>   drivers/pci/endpoint/pci-epc-core.c | 66 +++++++++++++++++++++++++++++
>>>>   include/linux/pci-epc.h             | 33 +++++++++++++++
>>>>   2 files changed, 99 insertions(+)
>>>>
>>>> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
>>>> index 754afd115bbd..37758ca91d7f 100644
>>>> --- a/drivers/pci/endpoint/pci-epc-core.c
>>>> +++ b/drivers/pci/endpoint/pci-epc-core.c
>>>> @@ -433,6 +433,72 @@ void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>>>>   }
>>>>   EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
>>>>   
>>>> +/**
>>>> + * pci_epc_map_align() - Get the offset into and the size of a controller memory
>>>> + *			 address region needed to map a RC PCI address region
>>>> + * @epc: the EPC device on which address is allocated
>>>> + * @func_no: the physical endpoint function number in the EPC device
>>>> + * @vfunc_no: the virtual endpoint function number in the physical function
>>>> + * @pci_addr: PCI address to which the physical address should be mapped
>>>> + * @size: the size of the mapping starting from @pci_addr
>>>> + * @map: populate here the actual size and offset into the controller memory
>>>> + *       that must be allocated for the mapping
>>>> + *
>>>> + * Invoke the controller map_align operation to obtain the size and the offset
>>>> + * into a controller address region that must be allocated to map @size
>>>> + * bytes of the RC PCI address space starting from @pci_addr.
>>>> + *
>>>> + * The size of the mapping that can be handled by the controller is indicated
>>>> + * using the pci_size field of @map. This size may be smaller than the requested
>>>> + * @size. In such case, the function driver must handle the mapping using
>>>> + * several fragments. The offset into the controller memory for the effective
>>>> + * mapping of the @pci_addr..@pci_addr+@map->pci_size address range is indicated
>>>> + * using the map_ofst field of @map.
>>>> + */
>>>> +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>>>> +		      u64 pci_addr, size_t size, struct pci_epc_map *map)
>>>> +{
>>>> +	const struct pci_epc_features *features;
>>>> +	size_t mask;
>>>> +	int ret;
>>>> +
>>>> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>>>> +		return -EINVAL;
>>>> +
>>>> +	if (!size || !map)
>>>> +		return -EINVAL;
>>>> +
>>>> +	memset(map, 0, sizeof(*map));
>>>> +	map->pci_addr = pci_addr;
>>>> +	map->pci_size = size;
>>>> +
>>>> +	if (epc->ops->map_align) {
>>>> +		mutex_lock(&epc->lock);
>>>> +		ret = epc->ops->map_align(epc, func_no, vfunc_no, map);
>>>> +		mutex_unlock(&epc->lock);
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	/*
>>>> +	 * Assume a fixed alignment constraint as specified by the controller
>>>> +	 * features.
>>>> +	 */
>>>> +	features = pci_epc_get_features(epc, func_no, vfunc_no);
>>>> +	if (!features || !features->align) {
>>>> +		map->map_pci_addr = pci_addr;
>>>> +		map->map_size = size;
>>>> +		map->map_ofst = 0;
>>>> +	}
>>>
>>> The 'align' of pci_epc_features was initially added only to address the 
>>> inbound ATU constraints. This is also added as comment in [1]. The PCI 
>>> address restrictions (only fixed alignment constraint) were handled by 
>>> the host side driver and depends on the connected endpoint device 
>>> (atleast it was like that for pci_endpoint_test.c [2]).
>>> So pci-epf-test.c used the 'align' in pci_epc_features only as part of 
>>> pci_epf_alloc_space().
>>>
>>> Though I have abused 'align' of pci_epc_features in pci-epf-ntb.c using 
>>> it out of pci_epf_alloc_space(), I think we should keep the 'align' of 
>>> pci_epc_features only within pci_epf_alloc_space() and controllers with 
>>> any PCI address restrictions to implement ->map_align(). This could as 
>>> well be done in a phased manner to let controllers implement 
>>> ->map_align() and then remove using  pci_epc_features in 
>>> pci_epc_map_align(). Let me know what you think?
> 
> First you say that you want to avoid using epc_features->align inside
> pci_epc_map_align(), and then you say that we could do it in phases,
> and eventually stop using epc_features->align in pci_epc_map_align().
> 
> I'm confused... :)
> 
> Do you really want pci_epc_map_align() to make use of epc_features->align ?
> 
> Don't you mean ep->page_size ?
> (Please read the whole email to see my reasoning.)
> 
> 
>>
>> Yep, good idea. I will remove the use of "align" as a default alignment
>> constraint. For controllers that have a fixed alignment constraint (not
>> necessarilly epc->features->align), it is trivial to provide a generic helper
>> function that implements the ->map_align method.
> 
> We can see that commit:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2a9a801620efac92885fc9cd53594c0b9aba87a4
> 
> Introduced epc_features->align and modified pci_epf_alloc_space() to use it.
> 
> From reading the commit, it appears that epc_features->align was intended to
> represent inbound iATU alignment requirement.
> 
> For DWC based controllers, the inbound iATU address must be aligned to:
> CX_ATU_MIN_REGION_SIZE.
> 
> AFAICT, epc_features->align currently has nothing to do with traffic outbound
> from the EP.

Yes, correct. It is for BARs, not for PCI address alignment constraint.

> For aligning the reads/writes to buffers allocated on the host side,
> we currently have .alignment in the host side driver:
> https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/misc/pci_endpoint_test.c#L966-L1021
> 
> Which should be set to the outbound iATU alignment requirement.
> 
> For DWC based controllers, the outbound iATU address must be aligned to:
> CX_ATU_MIN_REGION_SIZE.
> Additionally, we have ep->page_size, which defines the smallest outbound unit
> that can be mapped.
> (On DWC based controllers, tis is CX_ATU_MIN_REGION_SIZE.)
> 
> ep->page_size is used to specify the outbound alignment for e.g.
> dw_pcie_ep_raise_msi_irq() and dw_pcie_ep_raise_msix_irq():
> https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/pci/controller/dwc/pcie-designware-ep.c#L488
> https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/pci/controller/dwc/pcie-designware-ep.c#L555> which makes sure that we can write to the RC side MSI/MSI-X address
> while satisfying the outbound iATU alignment requirement.
> 
> See also:
> https://lore.kernel.org/linux-pci/20240402-pci2_upstream-v3-2-803414bdb430@nxp.com/
> 
> 
> 
> Now I understand that rockchip is the first one that does not have a fixed
> alignment.
> So for that platform, map_align() will be different from ep->page_size.
> (For all DWC based drivers the outbound iATU alignment requirement is
> the same as the page size.)

Yes. So we can have a generic map_align() implementation that all these drivers
can use as there .map_align method. No need to expose page size to the epc/epf
core code.

> However, it would be nice if:
> 1) We could have a default implementation of map_align() that by default uses
> ep->page_size. Platforms that have non-fixed alignment requirements could
> define their own map_align().

See above. The default implementation can be a helper function defined in epc
core that the drivers can use for their .map_align() method.

> 
> 2) We fix dw_pcie_ep_raise_msi_irq() and dw_pcie_ep_raise_msix_irq() to use
> the new pci_epc_map_align().

Why ? That is completely internal to the controller driver.

> 
> 3) It is getting too complicated with all these...
> epc_features->align, ep->page_size, map_align(), and .alignment in host driver.
> I think that we need to document each of these in Documentation/PCI/endpoint/

test host driver .alignment needs to be nuked. That one is nonsense.
ep->page_size needs to stay internal to the driver. .map_align method is enough
to handle any PCI address mapping constraint and will indicate memory size to
allocate, offset into it etc. And for the BARs alignment, .align feature is not
exactly great as it is not clear, but it is enough I think. So we could just
rename it to be clear. And even maybe remove it from features. I do not see why
an EPF needs to care about it given that epc core funstions are used to setup
the bars.

> 4) It would be nice if we could set page_size correctly for all the PCI device
> and vendor IDs that have defined an .alignment in drivers/misc/pci_endpoint_test.c
> in the correct EPC driver. That way, we should be able to completely remove all
> .alignment specified in drivers/misc/pci_endpoint_test.c.

The host side should be allowed to use any PCI address alignment it wants. So no
alignment communicated at all. It is the EP side that needs to deal with alignment.

> 5) Unfortunately drivers/misc/pci_endpoint_test.c defines a default alignment
> of 4K:
> https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/misc/pci_endpoint_test.c#L968
> https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/misc/pci_endpoint_test.c#L820
> 
> It would be nice if we could get rid of this as well. Or perhaps add an option
> to pci_test so that it does not use this 4k alignment, such that we can verify
> that pci_epc_map_align() is actually working.

Exactly. Get rid of any default alignment, add a test parameter to define one so
that we can test different alignment+size combinations.

> In my opinion 4) is the biggest win with this series, because it means that
> we define the alignment in the EPC driver, instead of needing to define it in
> each and every host side driver. But right now, this great improvement is not
> really visible for someone looking quickly at the current series.

Yes. Once in place, we can rework the test driver alignment stuff to make it
optional instead of mandatory because of bad handling on the EP side :)

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 01/18] PCI: endpoint: Introduce pci_epc_function_is_valid()

[Niklas Cassel]

On Sat, Mar 30, 2024 at 01:19:11PM +0900, Damien Le Moal wrote:
> Introduce the epc core helper function pci_epc_function_is_valid() to
> verify that an epc pointer, a physical function number and a virtual
> function number are all valid. This avoids repeating the code pattern:
> 
> if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
> 	return err;
> 
> if (vfunc_no > 0 && (!epc->max_vfs || vfunc_no > epc->max_vfs[func_no]))
> 	return err;
> 
> in many functions of the endpoint controller core code.
> 
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---

Reviewed-by: Niklas Cassel <cassel@kernel.org>

Re: [PATCH v2 04/18] PCI: endpoint: test: Use pci_epc_mem_map/unmap()

[Niklas Cassel]

On Sat, Mar 30, 2024 at 01:19:14PM +0900, Damien Le Moal wrote:
> Modify the endpoint test driver to use the functions pci_epc_mem_map()
> and pci_epc_mem_unmap() for the read, write and copy tests. For each
> test case, the transfer (dma or mmio) are executed in a loop to ensure
> that potentially partial mappings returned by pci_epc_mem_map() are
> correctly handled.
> 
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---

You probably want to rebase this series on top of:
[1] https://lore.kernel.org/linux-pci/20240314-pci-dbi-rework-v10-0-14a45c5a938e@linaro.org/
[2] https://lore.kernel.org/linux-pci/20240320113157.322695-1-cassel@kernel.org/

As these both modify pci-epf-test.c.

AFAICT both these series [1] (DBI rework v12, not v10) and [2] are fully
reviewed and seem to be ready to go.

They just seem to take a really long time to be picked up.


Kind regards,
Niklas

Re: [PATCH v2 06/18] PCI: endpoint: test: Implement link_down event operation

[Niklas Cassel]

On Wed, Apr 03, 2024 at 01:18:23PM +0530, Manivannan Sadhasivam wrote:
> On Sat, Mar 30, 2024 at 01:19:16PM +0900, Damien Le Moal wrote:
> > Implement the link_down event operation to stop the command execution
> > delayed work when the endpoint controller notifies a link down event.
> > 
> > Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> 
> This patch is already part of another series I posted [1] and under review. So
> this can be dropped.
> 
> - Mani
> 
> [1] https://lore.kernel.org/linux-pci/20240401-pci-epf-rework-v2-9-970dbe90b99d@linaro.org/

Mani, your patch does not use _sync(),
so I don't think that we can simply drop this patch.


Kind regards,
Niklas

> 
> > Reviewed-by: Frank Li <Frank.Li@nxp.com>
> > ---
> >  drivers/pci/endpoint/functions/pci-epf-test.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> > 
> > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> > index ab40c3182677..e6d4e1747c9f 100644
> > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > @@ -824,9 +824,19 @@ static int pci_epf_test_link_up(struct pci_epf *epf)
> >  	return 0;
> >  }
> >  
> > +static int pci_epf_test_link_down(struct pci_epf *epf)
> > +{
> > +	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
> > +
> > +	cancel_delayed_work_sync(&epf_test->cmd_handler);
> > +
> > +	return 0;
> > +}
> > +
> >  static const struct pci_epc_event_ops pci_epf_test_event_ops = {
> >  	.core_init = pci_epf_test_core_init,
> >  	.link_up = pci_epf_test_link_up,
> > +	.link_down = pci_epf_test_link_down,
> >  };
> >  
> >  static int pci_epf_test_alloc_space(struct pci_epf *epf)
> > -- 
> > 2.44.0
> > 
> 
> -- 
> மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 05/18] PCI: endpoint: test: Synchronously cancel command handler work

[Niklas Cassel]

On Wed, Apr 03, 2024 at 01:17:02PM +0530, Manivannan Sadhasivam wrote:
> On Sat, Mar 30, 2024 at 01:19:15PM +0900, Damien Le Moal wrote:
> > Replace the call to cancel_delayed_work() with a call to
> > cancel_delayed_work_sync() in pci_epf_test_unbind(). This ensures that
> > the command handler is really stopped when proceeding with dma and bar
> > cleanup.
> > 
> > Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> 
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> 
> - Mani
> 
> > Reviewed-by: Frank Li <Frank.Li@nxp.com>
> > ---

Reviewed-by: Niklas Cassel <cassel@kernel.org>

Re: [PATCH v2 03/18] PCI: endpoint: Introduce pci_epc_mem_map()/unmap()

[Niklas Cassel]

On Sat, Mar 30, 2024 at 01:19:13PM +0900, Damien Le Moal wrote:
> Introduce the function pci_epc_mem_map() to facilitate controller memory
> address allocation and mapping to a RC PCI address region in endpoint
> function drivers.
> 
> This function first uses pci_epc_map_align() to determine the controller
> memory address alignment (offset and size) constraints. The result of
> this function is used to allocate a controller physical memory region
> using pci_epc_mem_alloc_addr() and map it to the RC PCI address
> space with pci_epc_map_addr(). Since pci_epc_map_align() may indicate
> that a mapping can be smaller than the requested size, pci_epc_mem_map()
> may only partially map the RC PCI address region specified and return
> a smaller size for the effective mapping.
> 
> The counterpart of pci_epc_mem_map() to unmap and free the controller
> memory address region is pci_epc_mem_unmap().
> 
> Both functions operate using struct pci_epc_map data structure which is
> extended to contain the physical and virtual addresses of the allocated
> controller memory. Endpoint function drivers can use struct pci_epc_map
> to implement read/write accesses within the mapped RC PCI address region
> using the ->virt_addr and ->size fields.
> 
> This commit contains contributions from Rick Wertenbroek
> <rick.wertenbroek@gmail.com>.
> 
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>  drivers/pci/endpoint/pci-epc-core.c | 68 +++++++++++++++++++++++++++++
>  include/linux/pci-epc.h             |  6 +++
>  2 files changed, 74 insertions(+)
> 
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 37758ca91d7f..0095b54bdf9e 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -530,6 +530,74 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>  }
>  EXPORT_SYMBOL_GPL(pci_epc_map_addr);
>  
> +/**
> + * pci_epc_mem_map() - allocate and map CPU address to PCI address
> + * @epc: the EPC device on which the CPU address is to be allocated and mapped
> + * @func_no: the physical endpoint function number in the EPC device
> + * @vfunc_no: the virtual endpoint function number in the physical function
> + * @pci_addr: PCI address to which the CPU address should be mapped
> + * @size: the number of bytes to map starting from @pci_addr
> + * @map: where to return the mapping information
> + *
> + * Allocate a controller physical address region and map it to a RC PCI address
> + * region, taking into account the controller physical address mapping
> + * constraints (if any). Returns the effective size of the mapping, which may
> + * be less than @size, or a negative error code in case of error.
> + */
> +ssize_t pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +			u64 pci_addr, size_t size, struct pci_epc_map *map)
> +{
> +	int ret;
> +
> +	ret = pci_epc_map_align(epc, func_no, vfunc_no, pci_addr, size, map);
> +	if (ret)
> +		return ret;
> +
> +	map->virt_base = pci_epc_mem_alloc_addr(epc, &map->phys_base,
> +						map->map_size);
> +	if (!map->virt_base)
> +		return -ENOMEM;
> +
> +	map->phys_addr = map->phys_base + map->map_ofst;
> +	map->virt_addr = map->virt_base + map->map_ofst;
> +
> +	ret = pci_epc_map_addr(epc, func_no, vfunc_no, map->phys_base,
> +			       map->map_pci_addr, map->map_size);
> +	if (ret) {
> +		pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
> +				      map->map_size);
> +		return ret;
> +	}
> +
> +	return map->pci_size;

map->pci_size is of type size_t.
pci_epc_mem_map returns a type of ssize_t.

This means that on ILP32 you will truncate the result, and will only be
able to map a region of max size 2GB.

Could we perhaps change this function to return an int instead?
(0 on success). The mapped size can still be accessed in map->pci_size.


Kind regards,
Niklas

> +}
> +EXPORT_SYMBOL_GPL(pci_epc_mem_map);
> +
> +/**
> + * pci_epc_mem_unmap() - unmap from PCI address and free a CPU address region
> + * @epc: the EPC device on which the CPU address is allocated and mapped
> + * @func_no: the physical endpoint function number in the EPC device
> + * @vfunc_no: the virtual endpoint function number in the physical function
> + * @map: the mapping information
> + *
> + * Allocate and map local CPU address to a PCI address, accounting for the
> + * controller local CPU address alignment constraints.
> + */
> +void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		       struct pci_epc_map *map)
> +{
> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
> +		return;
> +
> +	if (!map || !map->pci_size)
> +		return;
> +
> +	pci_epc_unmap_addr(epc, func_no, vfunc_no, map->phys_base);
> +	pci_epc_mem_free_addr(epc, map->phys_base, map->virt_base,
> +			      map->map_size);
> +}
> +EXPORT_SYMBOL_GPL(pci_epc_mem_unmap);
> +
>  /**
>   * pci_epc_clear_bar() - reset the BAR
>   * @epc: the EPC device for which the BAR has to be cleared
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index 8cfb4aaf2628..86397a500b54 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -304,4 +304,10 @@ void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
>  				     phys_addr_t *phys_addr, size_t size);
>  void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
>  			   void __iomem *virt_addr, size_t size);
> +
> +ssize_t pci_epc_mem_map(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +			u64 pci_addr, size_t size, struct pci_epc_map *map);
> +void pci_epc_mem_unmap(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> +		       struct pci_epc_map *map);
> +
>  #endif /* __LINUX_PCI_EPC_H */
> -- 
> 2.44.0
> 

Re: [PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()

[Niklas Cassel]

On Fri, Apr 05, 2024 at 09:43:42PM +0900, Damien Le Moal wrote:
> On 4/5/24 21:20, Niklas Cassel wrote:
> > 
> > Now I understand that rockchip is the first one that does not have a fixed
> > alignment.
> > So for that platform, map_align() will be different from ep->page_size.
> > (For all DWC based drivers the outbound iATU alignment requirement is
> > the same as the page size.)
> 
> Yes. So we can have a generic map_align() implementation that all these drivers
> can use as there .map_align method. No need to expose page size to the epc/epf
> core code.

I don't follow.

ep->page_size is used by pci_epc_multi_mem_init(), pci_epc_mem_alloc_addr()
and pci_epc_mem_free_addr(), so it is used by EPC core.

pci_epc_mem_alloc_addr() currently uses it to align up an allocation to the
page size, so that an allocation from the PCI window/memory space is a multiple
of page_size. How can we avoid exposing the page size to EPC core?


For a DWC-based driver, the mapping part requires that the start address of
the mapping should be aligned to the page size.

But e.g.
drivers/pci/controller/pcie-rockchip-ep.c, sets page size (smallest allocation):
to 1 MB:
windows[i].page_size = SZ_1M;

But the mapping part for rockchip-ep appears to have different requirements.


> 
> > However, it would be nice if:
> > 1) We could have a default implementation of map_align() that by default uses
> > ep->page_size. Platforms that have non-fixed alignment requirements could
> > define their own map_align().
> 
> See above. The default implementation can be a helper function defined in epc
> core that the drivers can use for their .map_align() method.

Sounds good.


> > 2) We fix dw_pcie_ep_raise_msi_irq() and dw_pcie_ep_raise_msix_irq() to use
> > the new pci_epc_map_align().
> 
> Why ? That is completely internal to the controller driver.

Well, dw_pcie_ep_raise_msi_irq() and dw_pcie_ep_raise_msix_irq() currently does
some clearing of lower bits of the address before using .map_addr() to map the
an aligned outbound address. It will then write to the mapped address + some
offset.

Since it is already using .map_addr(), it seems like the perfect use case for
pci_epc_map_align(), as the function then would not need to do any clearing
of lower bits before mapping, nor writing to an offset within the mapping.

It would just use pci_epc_map_align() and then write to map->pci_addr.


> > 3) It is getting too complicated with all these...
> > epc_features->align, ep->page_size, map_align(), and .alignment in host driver.
> > I think that we need to document each of these in Documentation/PCI/endpoint/
> 
> test host driver .alignment needs to be nuked. That one is nonsense.
> ep->page_size needs to stay internal to the driver. .map_align method is enough
> to handle any PCI address mapping constraint and will indicate memory size to
> allocate, offset into it etc. And for the BARs alignment, .align feature is not
> exactly great as it is not clear, but it is enough I think. So we could just
> rename it to be clear. And even maybe remove it from features. I do not see why
> an EPF needs to care about it given that epc core funstions are used to setup
> the bars.

+1 on renaming it to bar_alignment or inbound_alignment or similar.

I don't think that we can remove it from epc_features. It is used by
pci_epf_alloc_space() which uses epc_features->align to ensure that
when an EPF driver allocates the backing memory for a BAR, the backing
memory is aligned to bar_alignment. (An allocation of size X is guaranteed
to be aligned to X.)


> > 4) It would be nice if we could set page_size correctly for all the PCI device
> > and vendor IDs that have defined an .alignment in drivers/misc/pci_endpoint_test.c
> > in the correct EPC driver. That way, we should be able to completely remove all
> > .alignment specified in drivers/misc/pci_endpoint_test.c.
> 
> The host side should be allowed to use any PCI address alignment it wants. So no
> alignment communicated at all. It is the EP side that needs to deal with alignment.

I think we are saying the same thing.
But in order to remove all .alignment uses in drivers/misc/pci_endpoint_test.c,
we will need to add modify the corresponding EPC driver to either:
- Define the ep->page_size, so that the generic map_align() implementation will
work.
(If you grep for page_size in drivers/pci/controller, you will see that
very few EPC drivers currently set ep->page_size, even though the PCI device
and vendor IDs for those same controllers have specified an alignment in
drivers/misc/pci_endpoint_test.c)
- Define a custom map_align() implementation.


> > 5) Unfortunately drivers/misc/pci_endpoint_test.c defines a default alignment
> > of 4K:
> > https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/misc/pci_endpoint_test.c#L968
> > https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/misc/pci_endpoint_test.c#L820
> > 
> > It would be nice if we could get rid of this as well. Or perhaps add an option
> > to pci_test so that it does not use this 4k alignment, such that we can verify
> > that pci_epc_map_align() is actually working.
> 
> Exactly. Get rid of any default alignment, add a test parameter to define one so
> that we can test different alignment+size combinations.
> 
> > In my opinion 4) is the biggest win with this series, because it means that
> > we define the alignment in the EPC driver, instead of needing to define it in
> > each and every host side driver. But right now, this great improvement is not
> > really visible for someone looking quickly at the current series.
> 
> Yes. Once in place, we can rework the test driver alignment stuff to make it
> optional instead of mandatory because of bad handling on the EP side :)

Perhaps it would be nice to have 5) implemented for this initial series,
so that it is possible to test that this new API is behaving as intended?


Kind regards,
Niklas

Re: [PATCH v2 06/18] PCI: endpoint: test: Implement link_down event operation

[Manivannan Sadhasivam]

On Fri, Apr 05, 2024 at 03:39:58PM +0200, Niklas Cassel wrote:
> On Wed, Apr 03, 2024 at 01:18:23PM +0530, Manivannan Sadhasivam wrote:
> > On Sat, Mar 30, 2024 at 01:19:16PM +0900, Damien Le Moal wrote:
> > > Implement the link_down event operation to stop the command execution
> > > delayed work when the endpoint controller notifies a link down event.
> > > 
> > > Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> > 
> > This patch is already part of another series I posted [1] and under review. So
> > this can be dropped.
> > 
> > - Mani
> > 
> > [1] https://lore.kernel.org/linux-pci/20240401-pci-epf-rework-v2-9-970dbe90b99d@linaro.org/
> 
> Mani, your patch does not use _sync(),
> so I don't think that we can simply drop this patch.
> 

Agree, I was planning to update it in my next version anyway.

- Mani

> 
> Kind regards,
> Niklas
> 
> > 
> > > Reviewed-by: Frank Li <Frank.Li@nxp.com>
> > > ---
> > >  drivers/pci/endpoint/functions/pci-epf-test.c | 10 ++++++++++
> > >  1 file changed, 10 insertions(+)
> > > 
> > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> > > index ab40c3182677..e6d4e1747c9f 100644
> > > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > > @@ -824,9 +824,19 @@ static int pci_epf_test_link_up(struct pci_epf *epf)
> > >  	return 0;
> > >  }
> > >  
> > > +static int pci_epf_test_link_down(struct pci_epf *epf)
> > > +{
> > > +	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
> > > +
> > > +	cancel_delayed_work_sync(&epf_test->cmd_handler);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > >  static const struct pci_epc_event_ops pci_epf_test_event_ops = {
> > >  	.core_init = pci_epf_test_core_init,
> > >  	.link_up = pci_epf_test_link_up,
> > > +	.link_down = pci_epf_test_link_down,
> > >  };
> > >  
> > >  static int pci_epf_test_alloc_space(struct pci_epf *epf)
> > > -- 
> > > 2.44.0
> > > 
> > 
> > -- 
> > மணிவண்ணன் சதாசிவம்

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v2 02/18] PCI: endpoint: Introduce pci_epc_map_align()

[Kishon Vijay Abraham I]

On 4/5/2024 5:50 PM, Niklas Cassel wrote:
> On Thu, Apr 04, 2024 at 11:43:47AM +0900, Damien Le Moal wrote:
>> On 4/3/24 21:33, Kishon Vijay Abraham I wrote:
>>> Hi Damien,
>>>
>>> On 3/30/2024 9:49 AM, Damien Le Moal wrote:
>>>> Some endpoint controllers have requirements on the alignment of the
>>>> controller physical memory address that must be used to map a RC PCI
>>>> address region. For instance, the rockchip endpoint controller uses
>>>> at most the lower 20 bits of a physical memory address region as the
>>>> lower bits of an RC PCI address. For mapping a PCI address region of
>>>> size bytes starting from pci_addr, the exact number of address bits
>>>> used is the number of address bits changing in the address range
>>>> [pci_addr..pci_addr + size - 1].
>>>>
>>>> For this example, this creates the following constraints:
>>>> 1) The offset into the controller physical memory allocated for a
>>>>      mapping depends on the mapping size *and* the starting PCI address
>>>>      for the mapping.
>>>> 2) A mapping size cannot exceed the controller windows size (1MB) minus
>>>>      the offset needed into the allocated physical memory, which can end
>>>>      up being a smaller size than the desired mapping size.
>>>>
>>>> Handling these constraints independently of the controller being used in
>>>> a PCI EP function driver is not possible with the current EPC API as
>>>> it only provides the ->align field in struct pci_epc_features.
>>>> Furthermore, this alignment is static and does not depend on a mapping
>>>> pci address and size.
>>>>
>>>> Solve this by introducing the function pci_epc_map_align() and the
>>>> endpoint controller operation ->map_align to allow endpoint function
>>>> drivers to obtain the size and the offset into a controller address
>>>> region that must be used to map an RC PCI address region. The size
>>>> of the physical address region provided by pci_epc_map_align() can then
>>>> be used as the size argument for the function pci_epc_mem_alloc_addr().
>>>> The offset into the allocated controller memory can be used to
>>>> correctly handle data transfers. Of note is that pci_epc_map_align() may
>>>> indicate upon return a mapping size that is smaller (but not 0) than the
>>>> requested PCI address region size. For such case, an endpoint function
>>>> driver must handle data transfers in fragments.
>>>>
>>>> The controller operation ->map_align is optional: controllers that do
>>>> not have any address alignment constraints for mapping a RC PCI address
>>>> region do not need to implement this operation. For such controllers,
>>>> pci_epc_map_align() always returns the mapping size as equal
>>>> to the requested size and an offset equal to 0.
>>>>
>>>> The structure pci_epc_map is introduced to represent a mapping start PCI
>>>> address, size and the size and offset into the controller memory needed
>>>> for mapping the PCI address region.
>>>>
>>>> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
>>>> ---
>>>>    drivers/pci/endpoint/pci-epc-core.c | 66 +++++++++++++++++++++++++++++
>>>>    include/linux/pci-epc.h             | 33 +++++++++++++++
>>>>    2 files changed, 99 insertions(+)
>>>>
>>>> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
>>>> index 754afd115bbd..37758ca91d7f 100644
>>>> --- a/drivers/pci/endpoint/pci-epc-core.c
>>>> +++ b/drivers/pci/endpoint/pci-epc-core.c
>>>> @@ -433,6 +433,72 @@ void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>>>>    }
>>>>    EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
>>>>    
>>>> +/**
>>>> + * pci_epc_map_align() - Get the offset into and the size of a controller memory
>>>> + *			 address region needed to map a RC PCI address region
>>>> + * @epc: the EPC device on which address is allocated
>>>> + * @func_no: the physical endpoint function number in the EPC device
>>>> + * @vfunc_no: the virtual endpoint function number in the physical function
>>>> + * @pci_addr: PCI address to which the physical address should be mapped
>>>> + * @size: the size of the mapping starting from @pci_addr
>>>> + * @map: populate here the actual size and offset into the controller memory
>>>> + *       that must be allocated for the mapping
>>>> + *
>>>> + * Invoke the controller map_align operation to obtain the size and the offset
>>>> + * into a controller address region that must be allocated to map @size
>>>> + * bytes of the RC PCI address space starting from @pci_addr.
>>>> + *
>>>> + * The size of the mapping that can be handled by the controller is indicated
>>>> + * using the pci_size field of @map. This size may be smaller than the requested
>>>> + * @size. In such case, the function driver must handle the mapping using
>>>> + * several fragments. The offset into the controller memory for the effective
>>>> + * mapping of the @pci_addr..@pci_addr+@map->pci_size address range is indicated
>>>> + * using the map_ofst field of @map.
>>>> + */
>>>> +int pci_epc_map_align(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>>>> +		      u64 pci_addr, size_t size, struct pci_epc_map *map)
>>>> +{
>>>> +	const struct pci_epc_features *features;
>>>> +	size_t mask;
>>>> +	int ret;
>>>> +
>>>> +	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
>>>> +		return -EINVAL;
>>>> +
>>>> +	if (!size || !map)
>>>> +		return -EINVAL;
>>>> +
>>>> +	memset(map, 0, sizeof(*map));
>>>> +	map->pci_addr = pci_addr;
>>>> +	map->pci_size = size;
>>>> +
>>>> +	if (epc->ops->map_align) {
>>>> +		mutex_lock(&epc->lock);
>>>> +		ret = epc->ops->map_align(epc, func_no, vfunc_no, map);
>>>> +		mutex_unlock(&epc->lock);
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	/*
>>>> +	 * Assume a fixed alignment constraint as specified by the controller
>>>> +	 * features.
>>>> +	 */
>>>> +	features = pci_epc_get_features(epc, func_no, vfunc_no);
>>>> +	if (!features || !features->align) {
>>>> +		map->map_pci_addr = pci_addr;
>>>> +		map->map_size = size;
>>>> +		map->map_ofst = 0;
>>>> +	}
>>>
>>> The 'align' of pci_epc_features was initially added only to address the
>>> inbound ATU constraints. This is also added as comment in [1]. The PCI
>>> address restrictions (only fixed alignment constraint) were handled by
>>> the host side driver and depends on the connected endpoint device
>>> (atleast it was like that for pci_endpoint_test.c [2]).
>>> So pci-epf-test.c used the 'align' in pci_epc_features only as part of
>>> pci_epf_alloc_space().
>>>
>>> Though I have abused 'align' of pci_epc_features in pci-epf-ntb.c using
>>> it out of pci_epf_alloc_space(), I think we should keep the 'align' of
>>> pci_epc_features only within pci_epf_alloc_space() and controllers with
>>> any PCI address restrictions to implement ->map_align(). This could as
>>> well be done in a phased manner to let controllers implement
>>> ->map_align() and then remove using  pci_epc_features in
>>> pci_epc_map_align(). Let me know what you think?
> 
> First you say that you want to avoid using epc_features->align inside
> pci_epc_map_align(), and then you say that we could do it in phases,
> and eventually stop using epc_features->align in pci_epc_map_align().
> 
> I'm confused... :)
> 
> Do you really want pci_epc_map_align() to make use of epc_features->align ?

Would like pci_epc_map_align() to not use epc_features->align as 
pci_epc_map_align() is for PCIe address programmed in outbound ATU 
(destination) and epc_features->align is for physical address programmed 
in inbound ATU (target for BAR accesses).

I mentioned "in phases" for if some platforms require 
pci_epc_map_align() to use epc_features->align, we could keep 
epc_features->align in pci_epc_map_align() till all of them implement 
the map_align() callback (and need not be part of this series itself). 
But eventually stop using epc_features->align in pci_epc_map_align() 
once all the platforms that require alignment implement ->map_align().

 > > Don't you mean ep->page_size ?
> (Please read the whole email to see my reasoning.)

page_size is for two purposes:
1) Dividing into fixed size blocks the outbound address space for 
simpler memory management
2) Alignment restrictions for source address (outbound address space) of 
the outbound ATU (so page_size is for source alignment restriction in 
outbound ATU and pci_epc_map_align() is for destination alignment 
restriction in outbound ATU. Source address would be an address in the 
outbound address space and destination address would be PCI address 
usually provided by the host).

Even if some platform doesn't require source alignment restriction, it 
still has to divide into fixed size blocks.
> 
> 
>>
>> Yep, good idea. I will remove the use of "align" as a default alignment
>> constraint. For controllers that have a fixed alignment constraint (not
>> necessarilly epc->features->align), it is trivial to provide a generic helper
>> function that implements the ->map_align method.
> 
> We can see that commit:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2a9a801620efac92885fc9cd53594c0b9aba87a4
> 
> Introduced epc_features->align and modified pci_epf_alloc_space() to use it.
> 
>  From reading the commit, it appears that epc_features->align was intended to
> represent inbound iATU alignment requirement.
> 
> For DWC based controllers, the inbound iATU address must be aligned to:
> CX_ATU_MIN_REGION_SIZE.
> 
> AFAICT, epc_features->align currently has nothing to do with traffic outbound
> from the EP.

It was initially added that way but I abused that in pci-epf-ntb.c
> 
> 
> For aligning the reads/writes to buffers allocated on the host side,
> we currently have .alignment in the host side driver:
> https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/misc/pci_endpoint_test.c#L966-L1021
> 
> Which should be set to the outbound iATU alignment requirement.
> 
> For DWC based controllers, the outbound iATU address must be aligned to:
> CX_ATU_MIN_REGION_SIZE.
> 
> 
> Additionally, we have ep->page_size, which defines the smallest outbound unit
> that can be mapped.
> (On DWC based controllers, tis is CX_ATU_MIN_REGION_SIZE.)
> 
> ep->page_size is used to specify the outbound alignment for e.g.
> dw_pcie_ep_raise_msi_irq() and dw_pcie_ep_raise_msix_irq():
> https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/pci/controller/dwc/pcie-designware-ep.c#L488
> https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/pci/controller/dwc/pcie-designware-ep.c#L555
> 
> which makes sure that we can write to the RC side MSI/MSI-X address
> while satisfying the outbound iATU alignment requirement.
> 
> See also:
> https://lore.kernel.org/linux-pci/20240402-pci2_upstream-v3-2-803414bdb430@nxp.com/
> 
> 
> 
> Now I understand that rockchip is the first one that does not have a fixed
> alignment.
> So for that platform, map_align() will be different from ep->page_size.
> (For all DWC based drivers the outbound iATU alignment requirement is
> the same as the page size.)
> 
> However, it would be nice if:
> 1) We could have a default implementation of map_align() that by default uses
> ep->page_size. Platforms that have non-fixed alignment requirements could
> define their own map_align().

IMHO generic/core functions should not overload ep->page_size or 
epc_features->align as each of them has their own specific purpose.

> 
> 2) We fix dw_pcie_ep_raise_msi_irq() and dw_pcie_ep_raise_msix_irq() to use
> the new pci_epc_map_align().
> 
> 3) It is getting too complicated with all these...
> epc_features->align, ep->page_size, map_align(), and .alignment in host driver.
> I think that we need to document each of these in Documentation/PCI/endpoint/

right, .alignment should be deprecated and each of the others should be 
documented to indicate the specific purpose it's added for.
> 
> 4) It would be nice if we could set page_size correctly for all the PCI device
> and vendor IDs that have defined an .alignment in drivers/misc/pci_endpoint_test.c
> in the correct EPC driver. That way, we should be able to completely remove all
> .alignment specified in drivers/misc/pci_endpoint_test.c.

We should remove .alignment specified in 
drivers/misc/pci_endpoint_test.c and each EPC driver should populate 
->map_align() callback to provide the correct alignment. Don't think 
this should change the page_size.
> 
> 5) Unfortunately drivers/misc/pci_endpoint_test.c defines a default alignment
> of 4K:
> https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/misc/pci_endpoint_test.c#L968
> https://github.com/torvalds/linux/blob/v6.9-rc2/drivers/misc/pci_endpoint_test.c#L820
> 
> It would be nice if we could get rid of this as well. Or perhaps add an option
> to pci_test so that it does not use this 4k alignment, such that we can verify
> that pci_epc_map_align() is actually working.

+1

Thanks,
Kishon

> 
> 
> 
> In my opinion 4) is the biggest win with this series, because it means that
> we define the alignment in the EPC driver, instead of needing to define it in
> each and every host side driver. But right now, this great improvement is not
> really visible for someone looking quickly at the current series.
> 
> 
> Kind regards,
> Niklas