[PATCH RFC V3 0/2] Generate device tree node for pci devices

[PATCH RFC V3 0/2] Generate device tree node for pci devices

[Lizhi Hou]

This patch series introduces OF overlay support for PCI devices which
primarily addresses two use cases. First, it provides a data driven method
to describe hardware peripherals that are present in a PCI endpoint and
hence can be accessed by the PCI host. Second, it allows reuse of a OF
compatible driver -- often used in SoC platforms -- in a PCI host based
system.

There are 2 series devices rely on this patch:

  1) Xilinx Alveo Accelerator cards (FPGA based device)
  2) Microchip LAN9662 Ethernet Controller

     Please see: https://lore.kernel.org/lkml/20220427094502.456111-1-clement.leger@bootlin.com/

Normally, the PCI core discovers PCI devices and their BARs using the
PCI enumeration process. However, the process does not provide a way to
discover the hardware peripherals that are present in a PCI device, and
which can be accessed through the PCI BARs. Also, the enumeration process
does not provide a way to associate MSI-X vectors of a PCI device with the
hardware peripherals that are present in the device. PCI device drivers
often use header files to describe the hardware peripherals and their
resources as there is no standard data driven way to do so. This patch
series proposes to use flattened device tree blob to describe the
peripherals in a data driven way. Based on previous discussion, using
device tree overlay is the best way to unflatten the blob and populate
platform devices. To use device tree overlay, there are three obvious
problems that need to be resolved.

First, we need to create a base tree for non-DT system such as x86_64. A
patch series has been submitted for this:
https://lore.kernel.org/lkml/20220624034327.2542112-1-frowand.list@gmail.com/
https://lore.kernel.org/lkml/20220216050056.311496-1-lizhi.hou@xilinx.com/

Second, a device tree node corresponding to the PCI endpoint is required
for overlaying the flattened device tree blob for that PCI endpoint.
Because PCI is a self-discoverable bus, a device tree node is usually not
created for PCI devices. This series adds support to generate a device
tree node for a PCI device which advertises itself using PCI quirks
infrastructure.

Third, we need to generate device tree nodes for PCI bridges since a child
PCI endpoint may choose to have a device tree node created.

This patch series is made up of three patches.

The first patch is adding OF interface to create or destroy OF node
dynamically.

The second patch introduces a kernel option, CONFIG_DYNAMIC_PCI_OF_NODEX.
When the option is turned on, the kernel will generate device tree nodes
for all PCI bridges unconditionally. The patch also shows how to use the
PCI quirks infrastructure, DECLARE_PCI_FIXUP_FINAL to generate a device
tree node for a device. Specifically, the patch generates a device tree
node for Xilinx Alveo U50 PCIe accelerator device. The generated device
tree nodes do not have any property.

The third patch adds basic properties ('reg', 'compatible' and
'device_type') to the dynamically generated device tree nodes. More
properties can be added in the future.

Here is the example of device tree nodes generated within the ARM64 QEMU.
# lspci -t    
-[0000:00]-+-00.0
           +-01.0-[01]--
           +-01.1-[02]----00.0
           +-01.2-[03]----00.0
           +-01.3-[04]----00.0
           +-01.4-[05]----00.0
           +-01.5-[06]--
           +-01.6-[07]--
           +-01.7-[08]--
           +-02.0-[09-0b]----00.0-[0a-0b]----00.0-[0b]--+-00.0
           |                                            \-00.1
           +-02.1-[0c]--
           \-03.0-[0d-0e]----00.0-[0e]----01.0

# tree /sys/firmware/devicetree/base/pcie\@10000000
/sys/firmware/devicetree/base/pcie@10000000
|-- #address-cells
|-- #interrupt-cells
|-- #size-cells
|-- bus-range
|-- compatible
|-- device_type
|-- dma-coherent
|-- interrupt-map
|-- interrupt-map-mask
|-- linux,pci-domain
|-- msi-parent
|-- name
|-- pci@1,0
|   |-- #address_cells
|   |-- #size_cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,1
|   |-- #address_cells
|   |-- #size_cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,2
|   |-- #address_cells
|   |-- #size_cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,3
|   |-- #address_cells
|   |-- #size_cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,4
|   |-- #address_cells
|   |-- #size_cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,5
|   |-- #address_cells
|   |-- #size_cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,6
|   |-- #address_cells
|   |-- #size_cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,7
|   |-- #address_cells
|   |-- #size_cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@2,0
|   |-- #address_cells
|   |-- #size_cells
|   |-- compatible
|   |-- device_type
|   |-- pci@0,0
|   |   |-- #address_cells
|   |   |-- #size_cells
|   |   |-- compatible
|   |   |-- device_type
|   |   |-- pci@0,0
|   |   |   |-- #address_cells
|   |   |   |-- #size_cells
|   |   |   |-- compatible
|   |   |   |-- dev@0,0
|   |   |   |   |-- compatible
|   |   |   |   `-- reg
|   |   |   |-- dev@0,1
|   |   |   |   |-- compatible
|   |   |   |   `-- reg
|   |   |   |-- device_type
|   |   |   |-- ranges
|   |   |   `-- reg
|   |   |-- ranges
|   |   `-- reg
|   |-- ranges
|   `-- reg
|-- pci@2,1
|   |-- #address_cells
|   |-- #size_cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@3,0
|   |-- #address_cells
|   |-- #size_cells
|   |-- compatible
|   |-- device_type
|   |-- pci@0,0
|   |   |-- #address_cells
|   |   |-- #size_cells
|   |   |-- compatible
|   |   |-- device_type
|   |   |-- ranges
|   |   `-- reg
|   |-- ranges
|   `-- reg
|-- ranges
`-- reg

Changes since RFC v2:
- Merged patch 3 with patch 2
- Added OF interfaces of_changeset_add_prop_* and use them to create
  properties.
- Added '#address-cells', '#size-cells' and 'ranges' properties.

Changes since RFC v1:
- Added one patch to create basic properties.
- To move DT related code out of PCI subsystem, replaced of_node_alloc()
  with of_create_node()/of_destroy_node()

Lizhi Hou (2):
  of: dynamic: Add interfaces for creating device node dynamically
  PCI: Create device tree node for selected devices

 drivers/of/dynamic.c        | 187 ++++++++++++++++++++++++++
 drivers/pci/Kconfig         |  12 ++
 drivers/pci/Makefile        |   1 +
 drivers/pci/bus.c           |   2 +
 drivers/pci/msi/irqdomain.c |   6 +-
 drivers/pci/of.c            |  71 ++++++++++
 drivers/pci/of_property.c   | 256 ++++++++++++++++++++++++++++++++++++
 drivers/pci/pci-driver.c    |   3 +-
 drivers/pci/pci.h           |  19 +++
 drivers/pci/quirks.c        |  11 ++
 drivers/pci/remove.c        |   1 +
 include/linux/of.h          |  24 ++++
 12 files changed, 590 insertions(+), 3 deletions(-)
 create mode 100644 drivers/pci/of_property.c

-- 
2.17.1

[PATCH RFC V3 1/2] of: dynamic: Add interfaces for creating device node dynamically

[Lizhi Hou]

of_create_node() creates device node dynamically. The parent device node
and full name are required for creating the node. It optionally creates
an OF changeset and attaches the newly created node to the changeset. The
device node pointer and the changeset pointer can be used to add
properties to the device node and apply the node to the base tree.

of_destroy_node() frees the device node created by of_create_node(). If
an OF changeset was also created for this node, it will destroy the
changeset before freeing the device node.

Expand of_changeset APIs to handle specific types of properties.
    of_changeset_add_prop_string()
    of_changeset_add_prop_string_array()
    of_changeset_add_prop_u32_array()

Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Signed-off-by: Sonal Santan <sonal.santan@amd.com>
Signed-off-by: Max Zhen <max.zhen@amd.com>
Reviewed-by: Brian Xu <brian.xu@amd.com>
---
 drivers/of/dynamic.c | 187 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h   |  24 ++++++
 2 files changed, 211 insertions(+)

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index cd3821a6444f..6b015b71e7fe 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -461,6 +461,72 @@ struct device_node *__of_node_dup(const struct device_node *np,
 	return NULL;
 }
 
+/**
+ * of_create_node - Dynamically create a device node
+ *
+ * @parent: Pointer to parent device node
+ * @full_name: Node full name
+ * @cset: Pointer to returning changeset
+ *
+ * Return: Pointer to the created device node or NULL in case of an error.
+ */
+struct device_node *of_create_node(struct device_node *parent,
+				   const char *full_name,
+				   struct of_changeset **cset)
+{
+	struct of_changeset *ocs;
+	struct device_node *np;
+	int ret;
+
+	np = __of_node_dup(NULL, full_name);
+	if (!np)
+		return NULL;
+	np->parent = parent;
+
+	if (!cset)
+		return np;
+
+	ocs = kmalloc(sizeof(*cset), GFP_KERNEL);
+	if (!ocs) {
+		of_node_put(np);
+		return NULL;
+	}
+
+	of_changeset_init(ocs);
+	ret = of_changeset_attach_node(ocs, np);
+	if (ret) {
+		of_changeset_destroy(ocs);
+		of_node_put(np);
+		kfree(ocs);
+		return NULL;
+	}
+
+	np->data = ocs;
+	*cset = ocs;
+
+	return np;
+}
+EXPORT_SYMBOL(of_create_node);
+
+/**
+ * of_destroy_node - Destroy a dynamically created device node
+ *
+ * @np: Pointer to dynamically created device node
+ *
+ */
+void of_destroy_node(struct device_node *np)
+{
+	struct of_changeset *ocs;
+
+	if (np->data) {
+		ocs = (struct of_changeset *)np->data;
+		of_changeset_destroy(ocs);
+		kfree(ocs);
+	}
+	of_node_put(np);
+}
+EXPORT_SYMBOL(of_destroy_node);
+
 static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
 {
 	if (ce->action == OF_RECONFIG_ATTACH_NODE &&
@@ -934,3 +1000,124 @@ int of_changeset_action(struct of_changeset *ocs, unsigned long action,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_changeset_action);
+
+static int of_changeset_add_prop_helper(struct of_changeset *ocs,
+					struct device_node *np,
+					const struct property *pp)
+{
+	struct property *new_pp;
+	int ret;
+
+	new_pp = __of_prop_dup(pp, GFP_KERNEL);
+	if (!new_pp)
+		return -ENOMEM;
+
+	ret = of_changeset_add_property(ocs, np, new_pp);
+	if (ret) {
+		kfree(new_pp->name);
+		kfree(new_pp->value);
+		kfree(new_pp);
+	}
+
+	return ret;
+}
+
+/**
+ * of_changeset_add_prop_string - Add a string property to a changeset
+ *
+ * @ocs:	changeset pointer
+ * @np:		device node pointer
+ * @prop_name:	name of the property to be added
+ * @str:	pointer to null terminated string
+ *
+ * Create a string property and add it to a changeset.
+ *
+ * Return: 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_add_prop_string(struct of_changeset *ocs,
+				 struct device_node *np,
+				 const char *prop_name, const char *str)
+{
+	struct property prop;
+
+	prop.name = (char *)prop_name;
+	prop.length = strlen(str) + 1;
+	prop.value = (void *)str;
+
+	return of_changeset_add_prop_helper(ocs, np, &prop);
+}
+EXPORT_SYMBOL_GPL(of_changeset_add_prop_string);
+
+/**
+ * of_changeset_add_prop_string_array - Add a string list property to
+ * a changeset
+ *
+ * @ocs:	changeset pointer
+ * @np:		device node pointer
+ * @prop_name:	name of the property to be added
+ * @str_array:	pointer to an array of null terminated strings
+ * @sz:		number of string array elements
+ *
+ * Create a string list property and add it to a changeset.
+ *
+ * Return: 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_add_prop_string_array(struct of_changeset *ocs,
+				       struct device_node *np,
+				       const char *prop_name,
+				       const char **str_array, size_t sz)
+{
+	struct property prop;
+	int i, ret;
+	char *vp;
+
+	prop.name = (char *)prop_name;
+
+	prop.length = 0;
+	for (i = 0; i < sz; i++)
+		prop.length += strlen(str_array[i]) + 1;
+
+	prop.value = kmalloc(prop.length, GFP_KERNEL);
+	if (!prop.value)
+		return -ENOMEM;
+
+	vp = prop.value;
+	for (i = 0; i < sz; i++) {
+		vp += snprintf(vp, (char *)prop.value + prop.length - vp, "%s",
+			       str_array[i]) + 1;
+	}
+	ret = of_changeset_add_prop_helper(ocs, np, &prop);
+	kfree(prop.value);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(of_changeset_add_prop_string_array);
+
+/**
+ * of_changeset_add_prop_string - Add a property of 32 bit integers
+ * property to a changeset
+ *
+ * @ocs:	changeset pointer
+ * @np:		device node pointer
+ * @prop_name:	name of the property to be added
+ * @u32:	pointer to an array of 32 bit integers
+ * @sz:		number of array elements
+ *
+ * Create a property of 32 bit integers and add it to a changeset.
+ *
+ * Return: 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_add_prop_u32_array(struct of_changeset *ocs,
+				    struct device_node *np,
+				    const char *prop_name,
+				    const u32 *array, size_t sz)
+{
+	struct property prop;
+
+	prop.name = (char *)prop_name;
+	prop.length = sizeof(u32) * sz;
+	prop.value = (void *)array;
+
+	return of_changeset_add_prop_helper(ocs, np, &prop);
+}
+EXPORT_SYMBOL_GPL(of_changeset_add_prop_u32_array);
diff --git a/include/linux/of.h b/include/linux/of.h
index 766d002bddb9..ba31036f0876 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -1505,6 +1505,30 @@ static inline int of_changeset_update_property(struct of_changeset *ocs,
 {
 	return of_changeset_action(ocs, OF_RECONFIG_UPDATE_PROPERTY, np, prop);
 }
+
+struct device_node *of_create_node(struct device_node *parent,
+				   const char *full_name,
+				   struct of_changeset **cset);
+void of_destroy_node(struct device_node *np);
+int of_changeset_add_prop_string(struct of_changeset *ocs,
+				 struct device_node *np,
+				 const char *prop_name, const char *str);
+int of_changeset_add_prop_string_array(struct of_changeset *ocs,
+				       struct device_node *np,
+				       const char *prop_name,
+				       const char **str_array, size_t sz);
+int of_changeset_add_prop_u32_array(struct of_changeset *ocs,
+				    struct device_node *np,
+				    const char *prop_name,
+				    const u32 *array, size_t sz);
+static inline int of_changeset_add_prop_u32(struct of_changeset *ocs,
+					    struct device_node *np,
+					    const char *prop_name,
+					    const u32 val)
+{
+	return of_changeset_add_prop_u32_array(ocs, np, prop_name, &val, 1);
+}
+
 #else /* CONFIG_OF_DYNAMIC */
 static inline int of_reconfig_notifier_register(struct notifier_block *nb)
 {
-- 
2.17.1

[PATCH RFC V3 2/2] PCI: Create device tree node for selected devices

[Lizhi Hou]

The PCIe endpoint device such as Xilinx Alveo PCIe card maps the register
spaces from multiple hardware peripherals to its PCIe BAR. Normally,
the PCI core discovers devices and BARs using the PCI enumeration process.
There is no infrastructure to discover the hardware peripherals that are
present in a PCI device, and which can be accessed through the PCI BARs.

For Alveo PCIe card, the card firmware provides a flattened device tree to
describe the hardware peripherals on its BARs. The Alveo card driver can
load this flattened device tree and leverage device tree framework to
generate platform devices for the hardware peripherals eventually.

Apparently, the device tree framework requires a device tree node for the
PCIe device. Thus, it can generate the device tree nodes for hardware
peripherals underneath. Because PCIe is self discoverable bus, there might
not be a device tree node created for PCIe devices. This patch is to add
support to generate device tree node for PCIe devices. It introduces a
kernel option. When the option is turned on, the kernel will generate
device tree nodes for PCI bridges unconditionally. It will also generate
a device tree node for Xilinx Alveo U50 by using PCI quirks.

Initially, the basic properties are added for the dynamically generated
device tree nodes.

Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Signed-off-by: Sonal Santan <sonal.santan@amd.com>
Signed-off-by: Max Zhen <max.zhen@amd.com>
Reviewed-by: Brian Xu <brian.xu@amd.com>
---
 drivers/pci/Kconfig         |  12 ++
 drivers/pci/Makefile        |   1 +
 drivers/pci/bus.c           |   2 +
 drivers/pci/msi/irqdomain.c |   6 +-
 drivers/pci/of.c            |  71 ++++++++++
 drivers/pci/of_property.c   | 256 ++++++++++++++++++++++++++++++++++++
 drivers/pci/pci-driver.c    |   3 +-
 drivers/pci/pci.h           |  19 +++
 drivers/pci/quirks.c        |  11 ++
 drivers/pci/remove.c        |   1 +
 10 files changed, 379 insertions(+), 3 deletions(-)
 create mode 100644 drivers/pci/of_property.c

diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 55c028af4bd9..8243a92fd97d 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -198,6 +198,18 @@ config PCI_HYPERV
 	  The PCI device frontend driver allows the kernel to import arbitrary
 	  PCI devices from a PCI backend to support PCI driver domains.
 
+config PCI_DYNAMIC_OF_NODES
+	bool "Device tree node for PCI devices"
+	depends on OF
+	select OF_DYNAMIC
+	help
+	  This option enables support for generating device tree nodes for some
+	  PCI devices. Thus, the driver of this kind can load and overlay
+	  flattened device tree for its downstream devices.
+
+	  Once this option is selected, the device tree nodes will be generated
+	  for all PCI/PCIE bridges.
+
 choice
 	prompt "PCI Express hierarchy optimization setting"
 	default PCIE_BUS_DEFAULT
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 2680e4c92f0a..cc8b4e01e29d 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -32,6 +32,7 @@ obj-$(CONFIG_PCI_P2PDMA)	+= p2pdma.o
 obj-$(CONFIG_XEN_PCIDEV_FRONTEND) += xen-pcifront.o
 obj-$(CONFIG_VGA_ARB)		+= vgaarb.o
 obj-$(CONFIG_PCI_DOE)		+= doe.o
+obj-$(CONFIG_PCI_DYNAMIC_OF_NODES) += of_property.o
 
 # Endpoint library must be initialized before its users
 obj-$(CONFIG_PCI_ENDPOINT)	+= endpoint/
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 3cef835b375f..8507cc32b61d 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -316,6 +316,8 @@ void pci_bus_add_device(struct pci_dev *dev)
 	 */
 	pcibios_bus_add_device(dev);
 	pci_fixup_device(pci_fixup_final, dev);
+	if (pci_is_bridge(dev))
+		of_pci_make_dev_node(dev);
 	pci_create_sysfs_dev_files(dev);
 	pci_proc_attach_device(dev);
 	pci_bridge_d3_update(dev);
diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
index e9cf318e6670..eeaf44169bfd 100644
--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -230,8 +230,10 @@ u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
 	pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
 
 	of_node = irq_domain_get_of_node(domain);
-	rid = of_node ? of_msi_map_id(&pdev->dev, of_node, rid) :
-			iort_msi_map_id(&pdev->dev, rid);
+	if (of_node && !of_node_check_flag(of_node, OF_DYNAMIC))
+		rid = of_msi_map_id(&pdev->dev, of_node, rid);
+	else
+		rid = iort_msi_map_id(&pdev->dev, rid);
 
 	return rid;
 }
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 196834ed44fe..0d5bbb08c61d 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -469,6 +469,8 @@ static int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *
 		} else {
 			/* We found a P2P bridge, check if it has a node */
 			ppnode = pci_device_to_OF_node(ppdev);
+			if (of_node_check_flag(ppnode, OF_DYNAMIC))
+				ppnode = NULL;
 		}
 
 		/*
@@ -599,6 +601,75 @@ int devm_of_pci_bridge_init(struct device *dev, struct pci_host_bridge *bridge)
 	return pci_parse_request_of_pci_ranges(dev, bridge);
 }
 
+#if IS_ENABLED(CONFIG_PCI_DYNAMIC_OF_NODES)
+
+void of_pci_remove_node(struct pci_dev *pdev)
+{
+	struct device_node *dt_node;
+
+	dt_node = pci_device_to_OF_node(pdev);
+	if (!dt_node || !of_node_check_flag(dt_node, OF_DYNAMIC))
+		return;
+	pdev->dev.of_node = NULL;
+
+	of_destroy_node(dt_node);
+}
+
+void of_pci_make_dev_node(struct pci_dev *pdev)
+{
+	struct device_node *parent, *dt_node = NULL;
+	const char *pci_type = "dev";
+	struct of_changeset *cset;
+	const char *full_name;
+	int ret;
+
+	/*
+	 * if there is already a device tree node linked to this device,
+	 * return immediately.
+	 */
+	if (pci_device_to_OF_node(pdev))
+		return;
+
+	/* check if there is device tree node for parent device */
+	if (!pdev->bus->self)
+		parent = pdev->bus->dev.of_node;
+	else
+		parent = pdev->bus->self->dev.of_node;
+	if (!parent)
+		return;
+
+	if (pci_is_bridge(pdev))
+		pci_type = "pci";
+
+	full_name = kasprintf(GFP_KERNEL, "%pOF/%s@%x,%x", parent, pci_type,
+			      PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
+	if (!full_name)
+		goto failed;
+
+	dt_node = of_create_node(parent, full_name, &cset);
+	if (!dt_node)
+		goto failed;
+	kfree(full_name);
+
+	ret = of_pci_add_properties(pdev, cset, dt_node);
+	if (ret)
+		goto failed;
+
+	ret = of_changeset_apply(cset);
+	if (ret)
+		goto failed;
+
+	pdev->dev.of_node = dt_node;
+
+	return;
+
+failed:
+	if (dt_node)
+		of_destroy_node(dt_node);
+	kfree(full_name);
+}
+#endif
+
 #endif /* CONFIG_PCI */
 
 /**
diff --git a/drivers/pci/of_property.c b/drivers/pci/of_property.c
new file mode 100644
index 000000000000..cc66fa7517e0
--- /dev/null
+++ b/drivers/pci/of_property.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2022, Advanced Micro Devices, Inc.
+ */
+
+#include <linux/pci.h>
+#include <linux/of.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include "pci.h"
+
+struct of_pci_addr_pair {
+	__be32		phys_hi;
+	__be32		phys_mid;
+	__be32		phys_lo;
+	__be32		size_hi;
+	__be32		size_lo;
+};
+
+struct of_pci_range {
+	__be32		child_addr_hi;
+	__be32		child_addr_mid;
+	__be32		child_addr_lo;
+	__be32		parent_addr_hi;
+	__be32		parent_addr_mid;
+	__be32		parent_addr_lo;
+	__be32		size_hi;
+	__be32		size_lo;
+};
+
+#define OF_PCI_ADDR_SPACE_CONFIG	0x0
+#define OF_PCI_ADDR_SPACE_IO		0x1
+#define OF_PCI_ADDR_SPACE_MEM32		0x2
+#define OF_PCI_ADDR_SPACE_MEM64		0x3
+
+#define OF_PCI_ADDR_FIELD_NONRELOC	BIT(31)
+#define OF_PCI_ADDR_FIELD_SS		GENMASK(25, 24)
+#define OF_PCI_ADDR_FIELD_PREFETCH	BIT(30)
+#define OF_PCI_ADDR_FIELD_BUS		GENMASK(23, 16)
+#define OF_PCI_ADDR_FIELD_DEV		GENMASK(15, 11)
+#define OF_PCI_ADDR_FIELD_FUNC		GENMASK(10, 8)
+#define OF_PCI_ADDR_FIELD_REG		GENMASK(7, 0)
+
+#define OF_PCI_ADDR_HI			GENMASK_ULL(63, 32)
+#define OF_PCI_ADDR_LO			GENMASK_ULL(31, 0)
+#define OF_PCI_SIZE_HI			GENMASK_ULL(63, 32)
+#define OF_PCI_SIZE_LO			GENMASK_ULL(31, 0)
+
+#define OF_PCI_ADDRESS_CELLS		3
+#define OF_PCI_SIZE_CELLS		2
+
+enum of_pci_prop_compatible {
+	PROP_COMPAT_PCI_VVVV_DDDD,
+	PROP_COMPAT_PCICLASS_CCSSPP,
+	PROP_COMPAT_PCICLASS_CCSS,
+	PROP_COMPAT_NUM,
+};
+
+static int of_pci_prop_device_type(struct pci_dev *pdev,
+				   struct of_changeset *ocs,
+				   struct device_node *np)
+{
+	return of_changeset_add_prop_string(ocs, np, "device_type", "pci");
+}
+
+static int of_pci_prop_address_cells(struct pci_dev *pdev,
+				     struct of_changeset *ocs,
+				     struct device_node *np)
+{
+	return of_changeset_add_prop_u32(ocs, np, "#address_cells",
+					 OF_PCI_ADDRESS_CELLS);
+}
+
+static int of_pci_prop_size_cells(struct pci_dev *pdev,
+				  struct of_changeset *ocs,
+				  struct device_node *np)
+{
+	return of_changeset_add_prop_u32(ocs, np, "#size_cells",
+					 OF_PCI_SIZE_CELLS);
+}
+
+static int of_pci_set_addr_flags(struct resource *res, u32 *addr_hi)
+{
+	u32 ss;
+
+	if (res->flags & IORESOURCE_IO)
+		ss = OF_PCI_ADDR_SPACE_IO;
+	else if (res->flags & IORESOURCE_MEM_64)
+		ss = OF_PCI_ADDR_SPACE_MEM64;
+	else if (res->flags & IORESOURCE_MEM)
+		ss = OF_PCI_ADDR_SPACE_MEM32;
+	else
+		return -EINVAL;
+
+	*addr_hi &= ~(OF_PCI_ADDR_FIELD_SS | OF_PCI_ADDR_FIELD_PREFETCH);
+	if (res->flags & IORESOURCE_PREFETCH)
+		*addr_hi |= OF_PCI_ADDR_FIELD_PREFETCH;
+
+	*addr_hi |= ss;
+
+	return 0;
+}
+
+static int of_pci_prop_ranges(struct pci_dev *pdev, struct of_changeset *ocs,
+			      struct device_node *np)
+{
+	struct of_pci_range rp[PCI_BRIDGE_RESOURCE_NUM];
+	struct resource *res;
+	int i = 0, j, ret;
+	u64 val64;
+	u32 val;
+
+	res = &pdev->resource[PCI_BRIDGE_RESOURCES];
+	for (j = 0; j < PCI_BRIDGE_RESOURCE_NUM; j++) {
+		if (!resource_size(&res[j]))
+			continue;
+
+		val = OF_PCI_ADDR_FIELD_NONRELOC;
+		if (of_pci_set_addr_flags(&res[j], &val))
+			continue;
+
+		rp[i].parent_addr_hi = cpu_to_be32(val);
+
+		val64 = res[j].start;
+		rp[i].parent_addr_mid =
+			cpu_to_be32(FIELD_GET(OF_PCI_ADDR_HI, val64));
+		rp[i].parent_addr_lo =
+			cpu_to_be32(FIELD_GET(OF_PCI_ADDR_LO, val64));
+
+		val64 = resource_size(&res[j]);
+		rp[i].size_hi = cpu_to_be32(FIELD_GET(OF_PCI_SIZE_HI, val64));
+		rp[i].size_lo = cpu_to_be32(FIELD_GET(OF_PCI_SIZE_LO, val64));
+
+		rp[i].child_addr_hi = rp[i].parent_addr_hi;
+		rp[i].child_addr_mid = rp[i].parent_addr_mid;
+		rp[i].child_addr_lo = rp[i].parent_addr_lo;
+		i++;
+	}
+
+	ret = of_changeset_add_prop_u32_array(ocs, np, "ranges", (u32 *)rp,
+					      i * sizeof(*rp) / sizeof(u32));
+
+	return ret;
+}
+
+static int of_pci_prop_reg(struct pci_dev *pdev, struct of_changeset *ocs,
+			   struct device_node *np)
+{
+	struct of_pci_addr_pair *reg;
+	int i = 1, resno, ret = 0;
+	u32 reg_val, base_addr;
+	resource_size_t sz;
+
+	reg = kzalloc(sizeof(*reg) * (PCI_STD_NUM_BARS + 1), GFP_KERNEL);
+	if (!reg)
+		return -ENOMEM;
+
+	reg_val = FIELD_PREP(OF_PCI_ADDR_FIELD_SS, OF_PCI_ADDR_SPACE_CONFIG) |
+		FIELD_PREP(OF_PCI_ADDR_FIELD_BUS, pdev->bus->number) |
+		FIELD_PREP(OF_PCI_ADDR_FIELD_DEV, PCI_SLOT(pdev->devfn)) |
+		FIELD_PREP(OF_PCI_ADDR_FIELD_FUNC, PCI_FUNC(pdev->devfn));
+	reg[0].phys_hi = cpu_to_be32(reg_val);
+
+	base_addr = PCI_BASE_ADDRESS_0;
+	for (resno = PCI_STD_RESOURCES; resno <= PCI_STD_RESOURCE_END;
+	     resno++, base_addr += 4) {
+		sz = pci_resource_len(pdev, resno);
+		if (!sz)
+			continue;
+
+		ret = of_pci_set_addr_flags(&pdev->resource[resno], &reg_val);
+		if (!ret)
+			continue;
+
+		reg_val &= ~OF_PCI_ADDR_FIELD_REG;
+		reg_val |= FIELD_PREP(OF_PCI_ADDR_FIELD_REG, base_addr);
+		reg[i].phys_hi = cpu_to_be32(reg_val);
+		reg[i].size_hi = cpu_to_be32(FIELD_GET(OF_PCI_SIZE_HI, sz));
+		reg[i].size_lo = cpu_to_be32(FIELD_GET(OF_PCI_SIZE_LO, sz));
+		i++;
+	}
+
+	ret = of_changeset_add_prop_u32_array(ocs, np, "reg", (u32 *)reg,
+					      i * sizeof(*reg) / sizeof(u32));
+	kfree(reg);
+
+	return ret;
+}
+
+static int of_pci_prop_compatible(struct pci_dev *pdev,
+				  struct of_changeset *ocs,
+				  struct device_node *np)
+{
+	const char *compat_strs[PROP_COMPAT_NUM] = { 0 };
+	int i, ret;
+
+	compat_strs[PROP_COMPAT_PCI_VVVV_DDDD] =
+		kasprintf(GFP_KERNEL, "pci%x,%x", pdev->vendor, pdev->device);
+	compat_strs[PROP_COMPAT_PCICLASS_CCSSPP] =
+		kasprintf(GFP_KERNEL, "pciclass,%06x", pdev->class);
+	compat_strs[PROP_COMPAT_PCICLASS_CCSS] =
+		kasprintf(GFP_KERNEL, "pciclass,%04x", pdev->class >> 8);
+
+	ret = of_changeset_add_prop_string_array(ocs, np, "compatible",
+						 compat_strs, PROP_COMPAT_NUM);
+	for (i = 0; i < PROP_COMPAT_NUM; i++)
+		kfree(compat_strs[i]);
+
+	return ret;
+}
+
+static int (*of_pci_endpoint_props[])(struct pci_dev *pdev,
+				      struct of_changeset *ocs,
+				      struct device_node *np) = {
+	of_pci_prop_reg,
+	of_pci_prop_compatible,
+	NULL
+};
+
+static int (*of_pci_bridge_props[])(struct pci_dev *pdev,
+				    struct of_changeset *ocs,
+				    struct device_node *np) = {
+	of_pci_prop_device_type,
+	of_pci_prop_address_cells,
+	of_pci_prop_size_cells,
+	of_pci_prop_ranges,
+	of_pci_prop_reg,
+	of_pci_prop_compatible,
+	NULL
+};
+
+int of_pci_add_properties(struct pci_dev *pdev, struct of_changeset *ocs,
+			  struct device_node *np)
+{
+	int (**prop_func)(struct pci_dev *pdev, struct of_changeset *ocs,
+			  struct device_node *np);
+	int i, ret;
+
+	if (pci_is_bridge(pdev))
+		prop_func = of_pci_bridge_props;
+	else
+		prop_func = of_pci_endpoint_props;
+
+	for (i = 0; prop_func[i]; i++) {
+		ret = prop_func[i](pdev, ocs, np);
+		if (ret) {
+			/*
+			 * The added properties will be released when the
+			 * changeset is destroyed.
+			 */
+			return ret;
+		}
+	}
+
+	return 0;
+}
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 49238ddd39ee..1540c4c9a770 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -1628,7 +1628,8 @@ static int pci_dma_configure(struct device *dev)
 	bridge = pci_get_host_bridge_device(to_pci_dev(dev));
 
 	if (IS_ENABLED(CONFIG_OF) && bridge->parent &&
-	    bridge->parent->of_node) {
+	    bridge->parent->of_node &&
+	    !of_node_check_flag(bridge->parent->of_node, OF_DYNAMIC)) {
 		ret = of_dma_configure(dev, bridge->parent->of_node, true);
 	} else if (has_acpi_companion(bridge)) {
 		struct acpi_device *adev = to_acpi_device_node(bridge->fwnode);
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 785f31086313..bd81dc4ca04f 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -678,6 +678,25 @@ static inline int devm_of_pci_bridge_init(struct device *dev, struct pci_host_br
 
 #endif /* CONFIG_OF */
 
+struct of_changeset;
+
+#ifdef CONFIG_PCI_DYNAMIC_OF_NODES
+void of_pci_make_dev_node(struct pci_dev *pdev);
+void of_pci_remove_node(struct pci_dev *pdev);
+int of_pci_add_properties(struct pci_dev *pdev, struct of_changeset *ocs,
+			  struct device_node *np);
+#else
+static inline void
+of_pci_make_dev_node(struct pci_dev *pdev)
+{
+}
+
+static inline void
+of_pci_remove_node(struct pci_dev *pdev)
+{
+}
+#endif /* CONFIG_PCI_DYNAMIC_OF_NODES */
+
 #ifdef CONFIG_PCIEAER
 void pci_no_aer(void);
 void pci_aer_init(struct pci_dev *dev);
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 4944798e75b5..5d76932f59ec 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5956,3 +5956,14 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56b1, aspm_l1_acceptable_latency
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56c0, aspm_l1_acceptable_latency);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56c1, aspm_l1_acceptable_latency);
 #endif
+
+/*
+ * For PCI device which have multiple downstream devices, its driver may use
+ * a flattened device tree to describe the downstream devices.
+ * To overlay the flattened device tree, the PCI device and all its ancestor
+ * devices need to have device tree nodes on system base device tree. Thus,
+ * before driver probing, it might need to add a device tree node as the final
+ * fixup.
+ */
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_XILINX, 0x5020, of_pci_make_dev_node);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_XILINX, 0x5021, of_pci_make_dev_node);
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 4c54c75050dc..0eaa9d9a3609 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -23,6 +23,7 @@ static void pci_stop_dev(struct pci_dev *dev)
 		device_release_driver(&dev->dev);
 		pci_proc_detach_device(dev);
 		pci_remove_sysfs_dev_files(dev);
+		of_pci_remove_node(dev);
 
 		pci_dev_assign_added(dev, false);
 	}
-- 
2.17.1

Re: [PATCH RFC V3 2/2] PCI: Create device tree node for selected devices

[Bjorn Helgaas]

On Fri, Nov 04, 2022 at 08:24:14AM -0700, Lizhi Hou wrote:
> The PCIe endpoint device such as Xilinx Alveo PCIe card maps the register
> spaces from multiple hardware peripherals to its PCIe BAR. Normally,
> the PCI core discovers devices and BARs using the PCI enumeration process.
> There is no infrastructure to discover the hardware peripherals that are
> present in a PCI device, and which can be accessed through the PCI BARs.
> 
> For Alveo PCIe card, the card firmware provides a flattened device tree to
> describe the hardware peripherals on its BARs. The Alveo card driver can
> load this flattened device tree and leverage device tree framework to
> generate platform devices for the hardware peripherals eventually.
> 
> Apparently, the device tree framework requires a device tree node for the
> PCIe device. Thus, it can generate the device tree nodes for hardware
> peripherals underneath. Because PCIe is self discoverable bus, there might
> not be a device tree node created for PCIe devices. This patch is to add
> support to generate device tree node for PCIe devices. It introduces a
> kernel option. When the option is turned on, the kernel will generate

Specify the kernel option here.  These last two sentences should
probably be a separate paragraph because they say specifically what
this patch does.

> device tree nodes for PCI bridges unconditionally.

> It will also generate
> a device tree node for Xilinx Alveo U50 by using PCI quirks.

I think I would split the Xilinx Alveo U50 quirk to a separate patch
from the infrastructure and make this patch more generic.

> +config PCI_DYNAMIC_OF_NODES
> +	bool "Device tree node for PCI devices"
> +	depends on OF
> +	select OF_DYNAMIC
> +	help
> +	  This option enables support for generating device tree nodes for some
> +	  PCI devices. Thus, the driver of this kind can load and overlay
> +	  flattened device tree for its downstream devices.
> +
> +	  Once this option is selected, the device tree nodes will be generated
> +	  for all PCI/PCIE bridges.

PCI/PCIe

Actually, in this context (and in the commit log), you should just say
"PCI" because there's nothing PCIe-specific here.

> +void of_pci_make_dev_node(struct pci_dev *pdev)
> +{
> +	struct device_node *parent, *dt_node = NULL;
> +	const char *pci_type = "dev";
> +	struct of_changeset *cset;
> +	const char *full_name;
> +	int ret;
> +
> +	/*
> +	 * if there is already a device tree node linked to this device,
> +	 * return immediately.

s/if there/If there/

> +	 */
> +	if (pci_device_to_OF_node(pdev))
> +		return;
> +
> +	/* check if there is device tree node for parent device */

s/check/Check/

Follow the style of the file, which is "capitalize English sentences."

Re: [PATCH RFC V3 2/2] PCI: Create device tree node for selected devices

[Lizhi Hou]

Hi Bjorn,

Thanks for your comments. I will fix all these with next submission.

Lizhi

On 11/7/22 13:05, Bjorn Helgaas wrote:
> On Fri, Nov 04, 2022 at 08:24:14AM -0700, Lizhi Hou wrote:
>> The PCIe endpoint device such as Xilinx Alveo PCIe card maps the register
>> spaces from multiple hardware peripherals to its PCIe BAR. Normally,
>> the PCI core discovers devices and BARs using the PCI enumeration process.
>> There is no infrastructure to discover the hardware peripherals that are
>> present in a PCI device, and which can be accessed through the PCI BARs.
>>
>> For Alveo PCIe card, the card firmware provides a flattened device tree to
>> describe the hardware peripherals on its BARs. The Alveo card driver can
>> load this flattened device tree and leverage device tree framework to
>> generate platform devices for the hardware peripherals eventually.
>>
>> Apparently, the device tree framework requires a device tree node for the
>> PCIe device. Thus, it can generate the device tree nodes for hardware
>> peripherals underneath. Because PCIe is self discoverable bus, there might
>> not be a device tree node created for PCIe devices. This patch is to add
>> support to generate device tree node for PCIe devices. It introduces a
>> kernel option. When the option is turned on, the kernel will generate
> Specify the kernel option here.  These last two sentences should
> probably be a separate paragraph because they say specifically what
> this patch does.
>
>> device tree nodes for PCI bridges unconditionally.
>> It will also generate
>> a device tree node for Xilinx Alveo U50 by using PCI quirks.
> I think I would split the Xilinx Alveo U50 quirk to a separate patch
> from the infrastructure and make this patch more generic.
>
>> +config PCI_DYNAMIC_OF_NODES
>> +	bool "Device tree node for PCI devices"
>> +	depends on OF
>> +	select OF_DYNAMIC
>> +	help
>> +	  This option enables support for generating device tree nodes for some
>> +	  PCI devices. Thus, the driver of this kind can load and overlay
>> +	  flattened device tree for its downstream devices.
>> +
>> +	  Once this option is selected, the device tree nodes will be generated
>> +	  for all PCI/PCIE bridges.
> PCI/PCIe
>
> Actually, in this context (and in the commit log), you should just say
> "PCI" because there's nothing PCIe-specific here.
>
>> +void of_pci_make_dev_node(struct pci_dev *pdev)
>> +{
>> +	struct device_node *parent, *dt_node = NULL;
>> +	const char *pci_type = "dev";
>> +	struct of_changeset *cset;
>> +	const char *full_name;
>> +	int ret;
>> +
>> +	/*
>> +	 * if there is already a device tree node linked to this device,
>> +	 * return immediately.
> s/if there/If there/
>
>> +	 */
>> +	if (pci_device_to_OF_node(pdev))
>> +		return;
>> +
>> +	/* check if there is device tree node for parent device */
> s/check/Check/
>
> Follow the style of the file, which is "capitalize English sentences."

Re: [PATCH RFC V3 2/2] PCI: Create device tree node for selected devices

[Lizhi Hou]

Hi Bjorn,

Thanks for your comments. I will fix all these with next submission.

Lizhi

On 11/7/22 13:05, Bjorn Helgaas wrote:
> On Fri, Nov 04, 2022 at 08:24:14AM -0700, Lizhi Hou wrote:
>> The PCIe endpoint device such as Xilinx Alveo PCIe card maps the register
>> spaces from multiple hardware peripherals to its PCIe BAR. Normally,
>> the PCI core discovers devices and BARs using the PCI enumeration process.
>> There is no infrastructure to discover the hardware peripherals that are
>> present in a PCI device, and which can be accessed through the PCI BARs.
>>
>> For Alveo PCIe card, the card firmware provides a flattened device tree to
>> describe the hardware peripherals on its BARs. The Alveo card driver can
>> load this flattened device tree and leverage device tree framework to
>> generate platform devices for the hardware peripherals eventually.
>>
>> Apparently, the device tree framework requires a device tree node for the
>> PCIe device. Thus, it can generate the device tree nodes for hardware
>> peripherals underneath. Because PCIe is self discoverable bus, there might
>> not be a device tree node created for PCIe devices. This patch is to add
>> support to generate device tree node for PCIe devices. It introduces a
>> kernel option. When the option is turned on, the kernel will generate
> Specify the kernel option here.  These last two sentences should
> probably be a separate paragraph because they say specifically what
> this patch does.
>
>> device tree nodes for PCI bridges unconditionally.
>> It will also generate
>> a device tree node for Xilinx Alveo U50 by using PCI quirks.
> I think I would split the Xilinx Alveo U50 quirk to a separate patch
> from the infrastructure and make this patch more generic.
>
>> +config PCI_DYNAMIC_OF_NODES
>> +	bool "Device tree node for PCI devices"
>> +	depends on OF
>> +	select OF_DYNAMIC
>> +	help
>> +	  This option enables support for generating device tree nodes for some
>> +	  PCI devices. Thus, the driver of this kind can load and overlay
>> +	  flattened device tree for its downstream devices.
>> +
>> +	  Once this option is selected, the device tree nodes will be generated
>> +	  for all PCI/PCIE bridges.
> PCI/PCIe
>
> Actually, in this context (and in the commit log), you should just say
> "PCI" because there's nothing PCIe-specific here.
>
>> +void of_pci_make_dev_node(struct pci_dev *pdev)
>> +{
>> +	struct device_node *parent, *dt_node = NULL;
>> +	const char *pci_type = "dev";
>> +	struct of_changeset *cset;
>> +	const char *full_name;
>> +	int ret;
>> +
>> +	/*
>> +	 * if there is already a device tree node linked to this device,
>> +	 * return immediately.
> s/if there/If there/
>
>> +	 */
>> +	if (pci_device_to_OF_node(pdev))
>> +		return;
>> +
>> +	/* check if there is device tree node for parent device */
> s/check/Check/
>
> Follow the style of the file, which is "capitalize English sentences."