[PATCH v6 00/24] dmaengine: dw-edma: Add RP/EP local DMA controllers support

[PATCH v6 00/24] dmaengine: dw-edma: Add RP/EP local DMA controllers support

[Serge Semin]

This is a final patchset in the series created in the framework of
my Baikal-T1 PCIe/eDMA-related work:

[1: Done v5] PCI: dwc: Various fixes and cleanups
Link: https://lore.kernel.org/linux-pci/20220624143428.8334-1-Sergey.Semin@baikalelectronics.ru/
Merged: kernel 6.0-rc1
[2: Done v4] PCI: dwc: Add hw version and dma-ranges support
Link: https://lore.kernel.org/linux-pci/20220624143947.8991-1-Sergey.Semin@baikalelectronics.ru/
Merged: kernel 6.0-rc1
[3: In-review v6] PCI: dwc: Add generic resources and Baikal-T1 support
Link: https://lore.kernel.org/linux-pci/20221107204934.32655-1-Sergey.Semin@baikalelectronics.ru/
[4: Done v6] dmaengine: dw-edma: Add RP/EP local DMA support
Link: ---you are looking at it---

Note it is very recommended to merge the patchsets in the same order as
they are listed in the set above in order to have them applied smoothly.
So @Bjorn, @Lorenzo as we agreed let's merge the leftover patchsets
in via your repos.

Here is a short summary regarding this patchset. The series starts with
fixes patches. We discovered that the dw-edma-pcie.c driver incorrectly
initializes the LL/DT base addresses for the platforms with not matching
CPU and PCIe memory spaces. It is fixed by using the pci_bus_address()
method to get a correct base address. After that you can find a series of
the interleaved xfers fixes. It turned out the interleaved transfers
implementation didn't work quite correctly from the very beginning for
instance missing src/dst addresses initialization, etc. In the framework
of the next two patches we suggest to add a new platform-specific
callback - pci_address() and use it to convert the CPU address to the PCIe
space address. It is at least required for the DW eDMA remote End-point
setup on the platforms with not-matching CPU/PCIe address spaces. In case
of the DW eDMA local RP/EP setup the conversion will be done automatically
by the outbound iATU (if no DMA-bypass flag is specified for the
corresponding iATU window). Then we introduce a set of the patches to make
the DebugFS part of the code supporting the multi-eDMA controllers
platforms. It starts with several cleanup patches and is closed joining
the Read/Write channels into a single DMA-device as they originally should
have been. After that you can find the patches with adding the non-atomic
io-64 methods usage, dropping DT-region descriptors allocation, replacing
chip IDs with the device name. In addition to that in order to have the
eDMA embedded into the DW PCIe RP/EP supported we need to bypass the
dma-ranges-based memory ranges mapping since in case of the root port DT
node it's applicable for the peripheral PCIe devices only. Finally at the
series closure we introduce a generic DW eDMA controller support being
available in the DW PCIe Root Port/Endpoint driver.

Link: https://lore.kernel.org/linux-pci/20220324014836.19149-1-Sergey.Semin@baikalelectronics.ru/
Changelog v2:
- Drop the patches:
  [PATCH 1/25] dmaengine: dw-edma: Drop dma_slave_config.direction field usage
  [PATCH 2/25] dmaengine: dw-edma: Fix eDMA Rd/Wr-channels and DMA-direction semantics
  since they are going to be merged in in the framework of the
  Frank's patchset.
- Add a new patch: "dmaengine: dw-edma: Release requested IRQs on
  failure."
- Drop __iomem qualifier from the struct dw_edma_debugfs_entry instance
  definition in the dw_edma_debugfs_u32_get() method. (@Manivannan)
- Add a new patch: "dmaengine: dw-edma: Rename DebugFS dentry variables to
  'dent'." (@Manivannan)
- Slightly extend the eDMA name array size. (@Manivannan)
- Change the specific DMA mapping comment a bit to being
  clearer. (@Manivannan)
- Add a new patch: "PCI: dwc: Add generic iATU/eDMA CSRs space detection
  method."
- Don't fail eDMA detection procedure if the DW eDMA driver couldn't probe
  device. That happens if the driver is disabled. (@Manivannan)
- Add "dma" registers resource mapping procedure. (@Manivannan)
- Move the eDMA CSRs space detection into the dw_pcie_map_detect() method.
- Remove eDMA on the dw_pcie_ep_init() internal errors. (@Manivannan)
- Remove eDMA in the dw_pcie_ep_exit() method.
- Move the dw_pcie_edma_detect() method execution to the tail of the
  dw_pcie_ep_init() function.

Link: https://lore.kernel.org/linux-pci/20220503225104.12108-1-Sergey.Semin@baikalelectronics.ru/
Changelog v3:
- Conditionally set dchan->dev->device.dma_coherent field since it can
  be missing on some platforms. (@Manivannan)
- Drop the patch: "PCI: dwc: Add generic iATU/eDMA CSRs space detection
  method". A similar modification has been done in another patchset.
- Add more comprehensive and less regression prune eDMA block detection
  procedure.
- Drop the patch: "dma-direct: take dma-ranges/offsets into account in
  resource mapping". It will be separately reviewed.
- Remove Manivannan tb tag from the modified patches.
- Rebase onto the kernel v5.18.

Link: https://lore.kernel.org/linux-pci/20220610091459.17612-1-Sergey.Semin@baikalelectronics.ru
Changelog v4:
- Rabase onto the laters Frank Li series:
Link: https://lore.kernel.org/all/20220524152159.2370739-1-Frank.Li@nxp.com/
- Add Vinod' Ab-tag.
- Rebase onto the kernel v5.19-rcX.

Link: https://lore.kernel.org/linux-pci/20220728142841.12305-1-Sergey.Semin@baikalelectronics.ru
Changelog v5:
- Just resend.
- Rebase onto the kernel v6.0-rc2.

Link: https://lore.kernel.org/linux-pci/20220822185332.26149-1-Sergey.Semin@baikalelectronics.ru
Changelog v6:
- Fix some patchlog and in-line comments misspells. (@Bjorn)
- Directly call *_dma_configure() method on the DW eDMA channel child
  device used for the DMA buffers mapping. (@Robin)
- Explicitly set the DMA-mask of the child device in the channel
  allocation proecedure. (@Robin)
- Rebase onto the kernel v6.1-rc3.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-By: Vinod Koul <vkoul@kernel.org>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>
Cc: "Krzysztof Wilczyński" <kw@linux.com>
Cc: caihuoqing <caihuoqing@baidu.com>
Cc: linux-pci@vger.kernel.org
Cc: dmaengine@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Serge Semin (24):
  dmaengine: Fix dma_slave_config.dst_addr description
  dmaengine: dw-edma: Release requested IRQs on failure
  dmaengine: dw-edma: Convert ll/dt phys-address to PCIe bus/DMA address
  dmaengine: dw-edma: Fix missing src/dst address of the interleaved
    xfers
  dmaengine: dw-edma: Don't permit non-inc interleaved xfers
  dmaengine: dw-edma: Fix invalid interleaved xfers semantics
  dmaengine: dw-edma: Add CPU to PCIe bus address translation
  dmaengine: dw-edma: Add PCIe bus address getter to the remote EP
    glue-driver
  dmaengine: dw-edma: Drop chancnt initialization
  dmaengine: dw-edma: Fix DebugFS reg entry type
  dmaengine: dw-edma: Stop checking debugfs_create_*() return value
  dmaengine: dw-edma: Add dw_edma prefix to the DebugFS nodes descriptor
  dmaengine: dw-edma: Convert DebugFS descs to being kz-allocated
  dmaengine: dw-edma: Rename DebugFS dentry variables to 'dent'
  dmaengine: dw-edma: Simplify the DebugFS context CSRs init procedure
  dmaengine: dw-edma: Move eDMA data pointer to DebugFS node descriptor
  dmaengine: dw-edma: Join Write/Read channels into a single device
  dmaengine: dw-edma: Use DMA-engine device DebugFS subdirectory
  dmaengine: dw-edma: Use non-atomic io-64 methods
  dmaengine: dw-edma: Drop DT-region allocation
  dmaengine: dw-edma: Replace chip ID number with device name
  dmaengine: dw-edma: Bypass dma-ranges mapping for the local setup
  dmaengine: dw-edma: Skip cleanup procedure if no private data found
  PCI: dwc: Add DW eDMA engine support

 drivers/dma/dw-edma/dw-edma-core.c            | 240 ++++++-----
 drivers/dma/dw-edma/dw-edma-core.h            |  10 +-
 drivers/dma/dw-edma/dw-edma-pcie.c            |  24 +-
 drivers/dma/dw-edma/dw-edma-v0-core.c         |  60 +--
 drivers/dma/dw-edma/dw-edma-v0-core.h         |   1 -
 drivers/dma/dw-edma/dw-edma-v0-debugfs.c      | 372 ++++++++----------
 drivers/dma/dw-edma/dw-edma-v0-debugfs.h      |   5 -
 .../pci/controller/dwc/pcie-designware-ep.c   |  12 +-
 .../pci/controller/dwc/pcie-designware-host.c |  13 +-
 drivers/pci/controller/dwc/pcie-designware.c  | 186 +++++++++
 drivers/pci/controller/dwc/pcie-designware.h  |  20 +
 include/linux/dma/edma.h                      |  18 +-
 include/linux/dmaengine.h                     |   2 +-
 13 files changed, 607 insertions(+), 356 deletions(-)

-- 
2.38.0

[PATCH v6 01/24] dmaengine: Fix dma_slave_config.dst_addr description

[Serge Semin]

Most likely due to a copy-paste mistake the dst_addr member of the
dma_slave_config structure has been marked as ignored if the !source!
address belong to the memory. That is relevant to the src_addr field of
the structure while the dst_addr field as containing a destination device
address is supposed to be ignored if the destination is the CPU memory.
Let's fix the field description accordingly.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 include/linux/dmaengine.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index c923f4e60f24..0c020682d894 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -394,7 +394,7 @@ enum dma_slave_buswidth {
  * should be read (RX), if the source is memory this argument is
  * ignored.
  * @dst_addr: this is the physical address where DMA slave data
- * should be written (TX), if the source is memory this argument
+ * should be written (TX), if the destination is memory this argument
  * is ignored.
  * @src_addr_width: this is the width in bytes of the source (RX)
  * register where DMA data shall be read. If the source
-- 
2.38.0

[PATCH v6 02/24] dmaengine: dw-edma: Release requested IRQs on failure

[Serge Semin]

From very beginning of the DW eDMA driver live in the kernel the method
dw_edma_irq_request() hasn't been designed quite correct. In case if the
request_irq() method fails to initialize the IRQ handler at some point the
previously requested IRQs will be left initialized. It's prune to errors
up to the system crash. Let's fix that by releasing the previously
requested IRQs in the cleanup-on-error path of the dw_edma_irq_request()
function.

Fixes: e63d79d1ffcd ("dmaengine: Add Synopsys eDMA IP core driver")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

---

Changelog v2:
- This is a new patch added in v2 iteration of the series.
---
 drivers/dma/dw-edma/dw-edma-core.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index c54b24ff5206..a8c1bd9c7ae9 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -893,10 +893,8 @@ static int dw_edma_irq_request(struct dw_edma *dw,
 						dw_edma_interrupt_read,
 					  IRQF_SHARED, dw->name,
 					  &dw->irq[i]);
-			if (err) {
-				dw->nr_irqs = i;
-				return err;
-			}
+			if (err)
+				goto err_irq_free;
 
 			if (irq_get_msi_desc(irq))
 				get_cached_msi_msg(irq, &dw->irq[i].msi);
@@ -905,6 +903,14 @@ static int dw_edma_irq_request(struct dw_edma *dw,
 		dw->nr_irqs = i;
 	}
 
+	return 0;
+
+err_irq_free:
+	for  (i--; i >= 0; i--) {
+		irq = chip->ops->irq_vector(dev, i);
+		free_irq(irq, &dw->irq[i]);
+	}
+
 	return err;
 }
 
-- 
2.38.0

[PATCH v6 03/24] dmaengine: dw-edma: Convert ll/dt phys-address to PCIe bus/DMA address

[Serge Semin]

In accordance with the dw_edma_region.paddr field semantics it is supposed
to be initialized with a memory base address visible by the DW eDMA
controller. If the DMA engine is embedded into the DW PCIe Host/EP
controller, then the address should belong to the Local CPU/Application
memory. If eDMA is remotely accessible across the PCIe bus via the PCIe
memory IOs, then the address needs to be a part of the PCIe bus memory
space. The later case hasn't been well covered in the corresponding
glue-driver. Since in general the PCIe memory space doesn't have to match
the CPU memory space and the pci_dev.resource[] arrays contain the
resources defined in the CPU memory space, a proper conversion needs to be
performed, otherwise either the driver won't properly work or much worse
the memory corruption will happen. The conversion can be done by means of
the pci_bus_address() method. Let's use it to retrieve the LL, DT and CSRs
PCIe memory ranges.

Note in addition to that we need to extend the dw_edma_region.paddr field
size. The field normally contains a memory range base address to be set in
the DW eDMA Linked-List pointer register or as a base address of the
Linked-List data buffer. In accordance with [1] the LL range is supposed
to be created in the Local CPU/Application memory, but depending on the DW
eDMA utilization the memory can be created as a part of the PCIe bus
address space (as in the case of the DW PCIe EP prototype kit). Thus in
the former case the dw_edma_region.paddr field should have the dma_addr_t
type, while in the later one - pci_bus_addr_t. Seeing the corresponding
CSRs are always 64-bits wide let's convert the dw_edma_region.paddr field
type to be u64 and let the client code logic to make sure it has a valid
address visible by the DW eDMA controller. For instance the DW eDMA PCIe
glue-driver initializes the field with the addresses from the PCIe bus
memory space.

[1] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port,
    v.5.40a, March 2019, p.1103

Fixes: 41aaff2a2ac0 ("dmaengine: Add Synopsys eDMA IP PCIe glue-logic")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-pcie.c | 8 ++++----
 include/linux/dma/edma.h           | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
index d6b5e2463884..04c95cba1244 100644
--- a/drivers/dma/dw-edma/dw-edma-pcie.c
+++ b/drivers/dma/dw-edma/dw-edma-pcie.c
@@ -231,7 +231,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 			return -ENOMEM;
 
 		ll_region->vaddr += ll_block->off;
-		ll_region->paddr = pdev->resource[ll_block->bar].start;
+		ll_region->paddr = pci_bus_address(pdev, ll_block->bar);
 		ll_region->paddr += ll_block->off;
 		ll_region->sz = ll_block->sz;
 
@@ -240,7 +240,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 			return -ENOMEM;
 
 		dt_region->vaddr += dt_block->off;
-		dt_region->paddr = pdev->resource[dt_block->bar].start;
+		dt_region->paddr = pci_bus_address(pdev, dt_block->bar);
 		dt_region->paddr += dt_block->off;
 		dt_region->sz = dt_block->sz;
 	}
@@ -256,7 +256,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 			return -ENOMEM;
 
 		ll_region->vaddr += ll_block->off;
-		ll_region->paddr = pdev->resource[ll_block->bar].start;
+		ll_region->paddr = pci_bus_address(pdev, ll_block->bar);
 		ll_region->paddr += ll_block->off;
 		ll_region->sz = ll_block->sz;
 
@@ -265,7 +265,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 			return -ENOMEM;
 
 		dt_region->vaddr += dt_block->off;
-		dt_region->paddr = pdev->resource[dt_block->bar].start;
+		dt_region->paddr = pci_bus_address(pdev, dt_block->bar);
 		dt_region->paddr += dt_block->off;
 		dt_region->sz = dt_block->sz;
 	}
diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
index 7d8062e9c544..a864978ddd27 100644
--- a/include/linux/dma/edma.h
+++ b/include/linux/dma/edma.h
@@ -18,7 +18,7 @@
 struct dw_edma;
 
 struct dw_edma_region {
-	phys_addr_t	paddr;
+	u64		paddr;
 	void __iomem	*vaddr;
 	size_t		sz;
 };
-- 
2.38.0

[PATCH v6 04/24] dmaengine: dw-edma: Fix missing src/dst address of the interleaved xfers

[Serge Semin]

The interleaved DMA transfers support was added in the commit 85e7518f42c8
("dmaengine: dw-edma: Add device_prep_interleave_dma() support"). It
seems like the support was broken from the very beginning. Depending on
the selected channel either source or destination address are left
uninitialized which was obviously wrong. I don't really know how come the
original modification was working for the commit author. Anyway let's fix
it by initializing the destination address of the eDMA burst descriptors
for the DEV_TO_MEM interleaved operations and by initializing the source
address of the eDMA burst descriptors for the MEM_TO_DEV interleaved
operations.

Fixes: 85e7518f42c8 ("dmaengine: dw-edma: Add device_prep_interleave_dma() support")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index a8c1bd9c7ae9..778d91d9fc1b 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -455,6 +455,8 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 				 * and destination addresses are increased
 				 * by the same portion (data length)
 				 */
+			} else if (xfer->type == EDMA_XFER_INTERLEAVED) {
+				burst->dar = dst_addr;
 			}
 		} else {
 			burst->dar = dst_addr;
@@ -470,6 +472,8 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 				 * and destination addresses are increased
 				 * by the same portion (data length)
 				 */
+			}  else if (xfer->type == EDMA_XFER_INTERLEAVED) {
+				burst->sar = src_addr;
 			}
 		}
 
-- 
2.38.0

[PATCH v6 05/24] dmaengine: dw-edma: Don't permit non-inc interleaved xfers

[Serge Semin]

DW eDMA controller always increments both source and destination
addresses. Permitting DMA interleaved transfers with no src_inc/dst_inc
flags set may lead to unexpected behaviour for the device users. Let's fix
that by terminating the interleaved transfers if at least one of the
dma_interleaved_template.{src_inc,dst_inc} flag is initialized with false
value. Note in addition to that we need to increase the source and
destination addresses accordingly after each iteration.

Fixes: 85e7518f42c8 ("dmaengine: dw-edma: Add device_prep_interleave_dma() support")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-core.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 778d91d9fc1b..35588e14f79a 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -385,6 +385,8 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 			return NULL;
 		if (xfer->xfer.il->numf > 0 && xfer->xfer.il->frame_size > 0)
 			return NULL;
+		if (!xfer->xfer.il->src_inc || !xfer->xfer.il->dst_inc)
+			return NULL;
 	} else {
 		return NULL;
 	}
@@ -484,15 +486,13 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 			struct dma_interleaved_template *il = xfer->xfer.il;
 			struct data_chunk *dc = &il->sgl[i];
 
-			if (il->src_sgl) {
-				src_addr += burst->sz;
+			src_addr += burst->sz;
+			if (il->src_sgl)
 				src_addr += dmaengine_get_src_icg(il, dc);
-			}
 
-			if (il->dst_sgl) {
-				dst_addr += burst->sz;
+			dst_addr += burst->sz;
+			if (il->dst_sgl)
 				dst_addr += dmaengine_get_dst_icg(il, dc);
-			}
 		}
 	}
 
-- 
2.38.0

[PATCH v6 06/24] dmaengine: dw-edma: Fix invalid interleaved xfers semantics

[Serge Semin]

The interleaved DMA transfer support added in commit 85e7518f42c8
("dmaengine: dw-edma: Add device_prep_interleave_dma() support") seems
contradicting to what the DMA-engine defines. The next conditional
statements:
	if (!xfer->xfer.il->numf)
		return NULL;
	if (xfer->xfer.il->numf > 0 && xfer->xfer.il->frame_size > 0)
		return NULL;
basically mean that numf can't be zero and frame_size must always be zero,
otherwise the transfer won't be executed. But further the transfer
execution method takes the frames size from the
dma_interleaved_template.sgl[] array for each frame. That array in
accordance with [1] is supposed to be of
dma_interleaved_template.frame_size size, which as we discovered before
the code expects to be zero. So judging by the dw_edma_device_transfer()
implementation the method implies the dma_interleaved_template.sgl[] array
being of dma_interleaved_template.numf size, which is wrong. Since the
dw_edma_device_transfer() method doesn't permit
dma_interleaved_template.frame_size being non-zero then actual multi-chunk
interleaved transfer turns to be unsupported even though the code implies
having it supported.

Let's fix that by adding a fully functioning support of the interleaved
DMA transfers. First of all dma_interleaved_template.frame_size is
supposed to be greater or equal to one thus having at least simple linear
chunked frames. Secondly we can create a walk-through all over the chunks
and frames just by initializing the number of the eDMA burst transactios
as a multiple of dma_interleaved_template.numf and
dma_interleaved_template.frame_size and getting the frame_size-modulo of
the iteration step as an index of the dma_interleaved_template.sgl[]
array. The rest of the dw_edma_device_transfer() method code can be left
unchanged.

[1] include/linux/dmaengine.h: doc struct dma_interleaved_template

Fixes: 85e7518f42c8 ("dmaengine: dw-edma: Add device_prep_interleave_dma() support")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-core.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 35588e14f79a..d5c4192141ef 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -332,6 +332,7 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 	struct dw_edma_chunk *chunk;
 	struct dw_edma_burst *burst;
 	struct dw_edma_desc *desc;
+	size_t fsz = 0;
 	u32 cnt = 0;
 	int i;
 
@@ -381,9 +382,7 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 		if (xfer->xfer.sg.len < 1)
 			return NULL;
 	} else if (xfer->type == EDMA_XFER_INTERLEAVED) {
-		if (!xfer->xfer.il->numf)
-			return NULL;
-		if (xfer->xfer.il->numf > 0 && xfer->xfer.il->frame_size > 0)
+		if (!xfer->xfer.il->numf || xfer->xfer.il->frame_size < 1)
 			return NULL;
 		if (!xfer->xfer.il->src_inc || !xfer->xfer.il->dst_inc)
 			return NULL;
@@ -413,10 +412,8 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 		cnt = xfer->xfer.sg.len;
 		sg = xfer->xfer.sg.sgl;
 	} else if (xfer->type == EDMA_XFER_INTERLEAVED) {
-		if (xfer->xfer.il->numf > 0)
-			cnt = xfer->xfer.il->numf;
-		else
-			cnt = xfer->xfer.il->frame_size;
+		cnt = xfer->xfer.il->numf * xfer->xfer.il->frame_size;
+		fsz = xfer->xfer.il->frame_size;
 	}
 
 	for (i = 0; i < cnt; i++) {
@@ -438,7 +435,7 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 		else if (xfer->type == EDMA_XFER_SCATTER_GATHER)
 			burst->sz = sg_dma_len(sg);
 		else if (xfer->type == EDMA_XFER_INTERLEAVED)
-			burst->sz = xfer->xfer.il->sgl[i].size;
+			burst->sz = xfer->xfer.il->sgl[i % fsz].size;
 
 		chunk->ll_region.sz += burst->sz;
 		desc->alloc_sz += burst->sz;
@@ -481,10 +478,9 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 
 		if (xfer->type == EDMA_XFER_SCATTER_GATHER) {
 			sg = sg_next(sg);
-		} else if (xfer->type == EDMA_XFER_INTERLEAVED &&
-			   xfer->xfer.il->frame_size > 0) {
+		} else if (xfer->type == EDMA_XFER_INTERLEAVED) {
 			struct dma_interleaved_template *il = xfer->xfer.il;
-			struct data_chunk *dc = &il->sgl[i];
+			struct data_chunk *dc = &il->sgl[i % fsz];
 
 			src_addr += burst->sz;
 			if (il->src_sgl)
-- 
2.38.0

[PATCH v6 07/24] dmaengine: dw-edma: Add CPU to PCIe bus address translation

[Serge Semin]

Starting from commit 9575632052ba ("dmaengine: make slave address
physical") the source and destination addresses of the DMA-slave device
have been converted to being defined in CPU address space. It's DMA-device
driver responsibility to properly convert them to the reachable DMA bus
spaces. In case of the DW eDMA device, the source or destination
peripheral (slave) devices reside PCIe bus space. Thus we need to perform
the PCIe Host/EP windows-based (i.e. ranges DT-property) addresses
translation otherwise the eDMA transactions won't work as expected (or can
be even harmful) in case if the CPU and PCIe address spaces don't match.

Note 1. Even though the DMA interleaved template has both source and
destination addresses declared of dma_addr_t type only CPU memory range is
supposed to be mapped in a way so to be seen by the DMA device since it's
a subject of the DMA getting towards the system side. The device part must
not be mapped since slave device resides in the PCIe bus space, which
isn't affected by IOMMUs or iATU translations. DW PCIe eDMA generates
corresponding MWr/MRd TLPs on its own.

Note 2. This functionality is mainly required for the remote eDMA setup
since the CPU address must be manually translated into the PCIe bus space
before being written to LLI.{SAR,DAR}. If eDMA is embedded into the
locally accessible DW PCIe RP/EP software-based translation isn't required
since it will be done by hardware by means of the Outbound iATU as long as
the DMA_BYPASS flag is cleared. If the later flag is set or there is no
Outbound iATU entry found to which the SAR or DAR falls in (for Read and
Write channel respectfully), there won't be any translation performed but
DMA will proceed with the corresponding source/destination address as is.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-core.c | 18 +++++++++++++++++-
 include/linux/dma/edma.h           | 15 +++++++++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index d5c4192141ef..6c9f95a8e397 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -39,6 +39,17 @@ struct dw_edma_desc *vd2dw_edma_desc(struct virt_dma_desc *vd)
 	return container_of(vd, struct dw_edma_desc, vd);
 }
 
+static inline
+u64 dw_edma_get_pci_address(struct dw_edma_chan *chan, phys_addr_t cpu_addr)
+{
+	struct dw_edma_chip *chip = chan->dw->chip;
+
+	if (chip->ops->pci_address)
+		return chip->ops->pci_address(chip->dev, cpu_addr);
+
+	return cpu_addr;
+}
+
 static struct dw_edma_burst *dw_edma_alloc_burst(struct dw_edma_chunk *chunk)
 {
 	struct dw_edma_burst *burst;
@@ -327,11 +338,11 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 {
 	struct dw_edma_chan *chan = dchan2dw_edma_chan(xfer->dchan);
 	enum dma_transfer_direction dir = xfer->direction;
-	phys_addr_t src_addr, dst_addr;
 	struct scatterlist *sg = NULL;
 	struct dw_edma_chunk *chunk;
 	struct dw_edma_burst *burst;
 	struct dw_edma_desc *desc;
+	u64 src_addr, dst_addr;
 	size_t fsz = 0;
 	u32 cnt = 0;
 	int i;
@@ -406,6 +417,11 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 		dst_addr = chan->config.dst_addr;
 	}
 
+	if (dir == DMA_DEV_TO_MEM)
+		src_addr = dw_edma_get_pci_address(chan, (phys_addr_t)src_addr);
+	else
+		dst_addr = dw_edma_get_pci_address(chan, (phys_addr_t)dst_addr);
+
 	if (xfer->type == EDMA_XFER_CYCLIC) {
 		cnt = xfer->xfer.cyclic.cnt;
 	} else if (xfer->type == EDMA_XFER_SCATTER_GATHER) {
diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
index a864978ddd27..380a0a3e251f 100644
--- a/include/linux/dma/edma.h
+++ b/include/linux/dma/edma.h
@@ -23,8 +23,23 @@ struct dw_edma_region {
 	size_t		sz;
 };
 
+/**
+ * struct dw_edma_core_ops - platform-specific eDMA methods
+ * @irq_vector:		Get IRQ number of the passed eDMA channel. Note the
+ *                      method accepts the channel id in the end-to-end
+ *                      numbering with the eDMA write channels being placed
+ *                      first in the row.
+ * @pci_address:	Get PCIe bus address corresponding to the passed CPU
+ *			address. Note there is no need in specifying this
+ *			function if the address translation is performed by
+ *			the DW PCIe RP/EP controller with the DW eDMA device in
+ *			subject and DMA_BYPASS isn't set for all the outbound
+ *			iATU windows. That will be done by the controller
+ *			automatically.
+ */
 struct dw_edma_core_ops {
 	int (*irq_vector)(struct device *dev, unsigned int nr);
+	u64 (*pci_address)(struct device *dev, phys_addr_t cpu_addr);
 };
 
 enum dw_edma_map_format {
-- 
2.38.0

[PATCH v6 08/24] dmaengine: dw-edma: Add PCIe bus address getter to the remote EP glue-driver

[Serge Semin]

In general the Synopsys PCIe EndPoint IP prototype kit can be attached to
a PCIe bus with any PCIe Host controller including to the one with
distinctive from CPU address space. Due to that we need to make sure that
the source and destination addresses of the DMA-slave devices are properly
converted to the PCIe bus address space, otherwise the DMA transaction
will not only work as expected, but may cause the memory corruption with
subsequent system crash. Let's do that by introducing a new
dw_edma_pcie_address() method defined in the dw-edma-pcie.c, which will
perform the denoted translation by using the pcibios_resource_to_bus()
method.

Fixes: 41aaff2a2ac0 ("dmaengine: Add Synopsys eDMA IP PCIe glue-logic")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

---

Note this patch depends on the patch "dmaengine: dw-edma: Add CPU to PCIe
bus address translation" from this series.
---
 drivers/dma/dw-edma/dw-edma-pcie.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
index 04c95cba1244..f530bacfd716 100644
--- a/drivers/dma/dw-edma/dw-edma-pcie.c
+++ b/drivers/dma/dw-edma/dw-edma-pcie.c
@@ -95,8 +95,23 @@ static int dw_edma_pcie_irq_vector(struct device *dev, unsigned int nr)
 	return pci_irq_vector(to_pci_dev(dev), nr);
 }
 
+static u64 dw_edma_pcie_address(struct device *dev, phys_addr_t cpu_addr)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct pci_bus_region region;
+	struct resource res = {
+		.flags = IORESOURCE_MEM,
+		.start = cpu_addr,
+		.end = cpu_addr,
+	};
+
+	pcibios_resource_to_bus(pdev->bus, &region, &res);
+	return region.start;
+}
+
 static const struct dw_edma_core_ops dw_edma_pcie_core_ops = {
 	.irq_vector = dw_edma_pcie_irq_vector,
+	.pci_address = dw_edma_pcie_address,
 };
 
 static void dw_edma_pcie_get_vsec_dma_data(struct pci_dev *pdev,
-- 
2.38.0

[PATCH v6 09/24] dmaengine: dw-edma: Drop chancnt initialization

[Serge Semin]

DMA device drivers aren't supposed to initialize the dma_device.chancnt
field. It will be done by the DMA-engine core in accordance with number of
added virtual DMA-channels. Pre-initializing it with some value causes
having a wrong number of channels printed in the device summary.

Fixes: e63d79d1ffcd ("dmaengine: Add Synopsys eDMA IP core driver")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-core.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 6c9f95a8e397..ecd3e8f7ac5d 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -817,7 +817,6 @@ static int dw_edma_channel_setup(struct dw_edma *dw, bool write,
 	dma->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
 	dma->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
 	dma->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
-	dma->chancnt = cnt;
 
 	/* Set DMA channel callbacks */
 	dma->dev = chip->dev;
-- 
2.38.0

[PATCH v6 10/24] dmaengine: dw-edma: Fix DebugFS reg entry type

[Serge Semin]

debugfs_entries structure declared in the dw-edma-v0-debugfs.c module
contains the DebugFS node' register address. The address is declared as
dma_addr_t type, but first it's assigned with virtual CPU IOMEM address
and then it's cast back to the virtual address. Even though the castes
sandwich will unlikely cause any problem since normally DMA address is at
least of the same size as the CPU virtual address, it's at the very least
redundant if not to say logically incorrect. Let's fix it by just stop
casting the pointer back and worth and just preserve the address as a
pointer to void with __iomem qualifier.

Fixes: 305aebeff879 ("dmaengine: Add Synopsys eDMA IP version 0 debugfs support")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
index 5226c9014703..8e61810dea4b 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
@@ -14,7 +14,7 @@
 #include "dw-edma-core.h"
 
 #define REGS_ADDR(name) \
-	((void __force *)&regs->name)
+	((void __iomem *)&regs->name)
 #define REGISTER(name) \
 	{ #name, REGS_ADDR(name) }
 
@@ -48,12 +48,13 @@ static struct {
 
 struct debugfs_entries {
 	const char				*name;
-	dma_addr_t				*reg;
+	void __iomem				*reg;
 };
 
 static int dw_edma_debugfs_u32_get(void *data, u64 *val)
 {
-	void __iomem *reg = (void __force __iomem *)data;
+	void __iomem *reg = data;
+
 	if (dw->chip->mf == EDMA_MF_EDMA_LEGACY &&
 	    reg >= (void __iomem *)&regs->type.legacy.ch) {
 		void __iomem *ptr = &regs->type.legacy.ch;
-- 
2.38.0

[PATCH v6 11/24] dmaengine: dw-edma: Stop checking debugfs_create_*() return value

[Serge Semin]

First of all they never return NULL. So checking their return value for
being not NULL just pointless. Secondly the DebugFS subsystem is designed
in a way to be used as simple as possible. So if one of the
debugfs_create_*() method in a hierarchy fails, the following methods will
just silently return the passed erroneous parental dentry. Finally the
code is supposed to be working no matter whether anything DebugFS-related
fails. So in order to make code simpler and DebugFS-independent let's drop
the debugfs_create_*() methods return value checking in the same way as
the most of the kernel drivers do.

Note in order to preserve some memory space we suggest to skip the DebugFS
nodes initialization if the file system in unavailable.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 20 +++++---------------
 1 file changed, 5 insertions(+), 15 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
index 8e61810dea4b..6e7f3ef60ca7 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
@@ -100,9 +100,8 @@ static void dw_edma_debugfs_create_x32(const struct debugfs_entries entries[],
 	int i;
 
 	for (i = 0; i < nr_entries; i++) {
-		if (!debugfs_create_file_unsafe(entries[i].name, 0444, dir,
-						entries[i].reg,	&fops_x32))
-			break;
+		debugfs_create_file_unsafe(entries[i].name, 0444, dir,
+					   entries[i].reg, &fops_x32);
 	}
 }
 
@@ -168,8 +167,6 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dir)
 	char name[16];
 
 	regs_dir = debugfs_create_dir(WRITE_STR, dir);
-	if (!regs_dir)
-		return;
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
 	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
@@ -184,8 +181,6 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dir)
 		snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
 
 		ch_dir = debugfs_create_dir(name, regs_dir);
-		if (!ch_dir)
-			return;
 
 		dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].wr, ch_dir);
 
@@ -237,8 +232,6 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dir)
 	char name[16];
 
 	regs_dir = debugfs_create_dir(READ_STR, dir);
-	if (!regs_dir)
-		return;
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
 	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
@@ -253,8 +246,6 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dir)
 		snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
 
 		ch_dir = debugfs_create_dir(name, regs_dir);
-		if (!ch_dir)
-			return;
 
 		dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].rd, ch_dir);
 
@@ -273,8 +264,6 @@ static void dw_edma_debugfs_regs(void)
 	int nr_entries;
 
 	regs_dir = debugfs_create_dir(REGISTERS_STR, dw->debugfs);
-	if (!regs_dir)
-		return;
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
 	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
@@ -285,6 +274,9 @@ static void dw_edma_debugfs_regs(void)
 
 void dw_edma_v0_debugfs_on(struct dw_edma *_dw)
 {
+	if (!debugfs_initialized())
+		return;
+
 	dw = _dw;
 	if (!dw)
 		return;
@@ -294,8 +286,6 @@ void dw_edma_v0_debugfs_on(struct dw_edma *_dw)
 		return;
 
 	dw->debugfs = debugfs_create_dir(dw->name, NULL);
-	if (!dw->debugfs)
-		return;
 
 	debugfs_create_u32("mf", 0444, dw->debugfs, &dw->chip->mf);
 	debugfs_create_u16("wr_ch_cnt", 0444, dw->debugfs, &dw->wr_ch_cnt);
-- 
2.38.0

[PATCH v6 12/24] dmaengine: dw-edma: Add dw_edma prefix to the DebugFS nodes descriptor

[Serge Semin]

The rest of the locally defined and used methods and structures have
dw_edma prefix in their names. It's right in accordance with the kernel
coding style to follow the locally defined rule of naming. Let's add that
prefix to the debugfs_entries structure too especially seeing it's name
may be confusing as if that structure belongs to the global DebugFS space.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
index 6e7f3ef60ca7..2121ffc33cf3 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
@@ -46,7 +46,7 @@ static struct {
 	void					__iomem *end;
 } lim[2][EDMA_V0_MAX_NR_CH];
 
-struct debugfs_entries {
+struct dw_edma_debugfs_entry {
 	const char				*name;
 	void __iomem				*reg;
 };
@@ -94,7 +94,7 @@ static int dw_edma_debugfs_u32_get(void *data, u64 *val)
 }
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, dw_edma_debugfs_u32_get, NULL, "0x%08llx\n");
 
-static void dw_edma_debugfs_create_x32(const struct debugfs_entries entries[],
+static void dw_edma_debugfs_create_x32(const struct dw_edma_debugfs_entry entries[],
 				       int nr_entries, struct dentry *dir)
 {
 	int i;
@@ -108,8 +108,7 @@ static void dw_edma_debugfs_create_x32(const struct debugfs_entries entries[],
 static void dw_edma_debugfs_regs_ch(struct dw_edma_v0_ch_regs __iomem *regs,
 				    struct dentry *dir)
 {
-	int nr_entries;
-	const struct debugfs_entries debugfs_regs[] = {
+	const struct dw_edma_debugfs_entry debugfs_regs[] = {
 		REGISTER(ch_control1),
 		REGISTER(ch_control2),
 		REGISTER(transfer_size),
@@ -120,6 +119,7 @@ static void dw_edma_debugfs_regs_ch(struct dw_edma_v0_ch_regs __iomem *regs,
 		REGISTER(llp.lsb),
 		REGISTER(llp.msb),
 	};
+	int nr_entries;
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
 	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, dir);
@@ -127,7 +127,7 @@ static void dw_edma_debugfs_regs_ch(struct dw_edma_v0_ch_regs __iomem *regs,
 
 static void dw_edma_debugfs_regs_wr(struct dentry *dir)
 {
-	const struct debugfs_entries debugfs_regs[] = {
+	const struct dw_edma_debugfs_entry debugfs_regs[] = {
 		/* eDMA global registers */
 		WR_REGISTER(engine_en),
 		WR_REGISTER(doorbell),
@@ -148,7 +148,7 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dir)
 		WR_REGISTER(ch67_imwr_data),
 		WR_REGISTER(linked_list_err_en),
 	};
-	const struct debugfs_entries debugfs_unroll_regs[] = {
+	const struct dw_edma_debugfs_entry debugfs_unroll_regs[] = {
 		/* eDMA channel context grouping */
 		WR_REGISTER_UNROLL(engine_chgroup),
 		WR_REGISTER_UNROLL(engine_hshake_cnt.lsb),
@@ -191,7 +191,7 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dir)
 
 static void dw_edma_debugfs_regs_rd(struct dentry *dir)
 {
-	const struct debugfs_entries debugfs_regs[] = {
+	const struct dw_edma_debugfs_entry debugfs_regs[] = {
 		/* eDMA global registers */
 		RD_REGISTER(engine_en),
 		RD_REGISTER(doorbell),
@@ -213,7 +213,7 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dir)
 		RD_REGISTER(ch45_imwr_data),
 		RD_REGISTER(ch67_imwr_data),
 	};
-	const struct debugfs_entries debugfs_unroll_regs[] = {
+	const struct dw_edma_debugfs_entry debugfs_unroll_regs[] = {
 		/* eDMA channel context grouping */
 		RD_REGISTER_UNROLL(engine_chgroup),
 		RD_REGISTER_UNROLL(engine_hshake_cnt.lsb),
@@ -256,7 +256,7 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dir)
 
 static void dw_edma_debugfs_regs(void)
 {
-	const struct debugfs_entries debugfs_regs[] = {
+	const struct dw_edma_debugfs_entry debugfs_regs[] = {
 		REGISTER(ctrl_data_arb_prior),
 		REGISTER(ctrl),
 	};
-- 
2.38.0

[PATCH v6 13/24] dmaengine: dw-edma: Convert DebugFS descs to being kz-allocated

[Serge Semin]

Currently all the DW eDMA DebugFS nodes descriptors are allocated on
stack, while the DW eDMA driver private data and CSR limits are statically
preserved. Such design won't work for the multi-eDMA platforms. As a
preparation to adding the multi-eDMA system setups support we need to have
each DebugFS node separately allocated and described. Afterwards we'll put
an addition info there like Read/Write channel flag, channel ID, DW eDMA
private data reference.

Note this conversion is mainly required due to having the legacy DW eDMA
controllers with indirect Read/Write channels context CSRs access. If we
didn't need to have a synchronized access to these registers the DebugFS
code of the driver would have been much simpler.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

---

Changelog v2:
- Drop __iomem qualifier from the struct dw_edma_debugfs_entry instance
  definition in the dw_edma_debugfs_u32_get() method. (@Manivannan)
---
 drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
index 2121ffc33cf3..78f15e4b07ac 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
@@ -53,7 +53,8 @@ struct dw_edma_debugfs_entry {
 
 static int dw_edma_debugfs_u32_get(void *data, u64 *val)
 {
-	void __iomem *reg = data;
+	struct dw_edma_debugfs_entry *entry = data;
+	void __iomem *reg = entry->reg;
 
 	if (dw->chip->mf == EDMA_MF_EDMA_LEGACY &&
 	    reg >= (void __iomem *)&regs->type.legacy.ch) {
@@ -94,14 +95,22 @@ static int dw_edma_debugfs_u32_get(void *data, u64 *val)
 }
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, dw_edma_debugfs_u32_get, NULL, "0x%08llx\n");
 
-static void dw_edma_debugfs_create_x32(const struct dw_edma_debugfs_entry entries[],
+static void dw_edma_debugfs_create_x32(const struct dw_edma_debugfs_entry ini[],
 				       int nr_entries, struct dentry *dir)
 {
+	struct dw_edma_debugfs_entry *entries;
 	int i;
 
+	entries = devm_kcalloc(dw->chip->dev, nr_entries, sizeof(*entries),
+			       GFP_KERNEL);
+	if (!entries)
+		return;
+
 	for (i = 0; i < nr_entries; i++) {
+		entries[i] = ini[i];
+
 		debugfs_create_file_unsafe(entries[i].name, 0444, dir,
-					   entries[i].reg, &fops_x32);
+					   &entries[i], &fops_x32);
 	}
 }
 
-- 
2.38.0

[PATCH v6 14/24] dmaengine: dw-edma: Rename DebugFS dentry variables to 'dent'

[Serge Semin]

Since we are about to add the eDMA channels direction support to the
debugfs module it will be confusing to have both the DebugFS directory and
the channels direction short names used in the same code. As a preparation
patch let's convert the DebugFS dentry 'dir' variables to having the
'dent' name so to prevent the confusion.

Suggested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

---

Changelog v2:
- This is a new patch added in v2. (@Manivannan)
---
 drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 46 ++++++++++++------------
 1 file changed, 23 insertions(+), 23 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
index 78f15e4b07ac..7bb3363b40e4 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
@@ -96,7 +96,7 @@ static int dw_edma_debugfs_u32_get(void *data, u64 *val)
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, dw_edma_debugfs_u32_get, NULL, "0x%08llx\n");
 
 static void dw_edma_debugfs_create_x32(const struct dw_edma_debugfs_entry ini[],
-				       int nr_entries, struct dentry *dir)
+				       int nr_entries, struct dentry *dent)
 {
 	struct dw_edma_debugfs_entry *entries;
 	int i;
@@ -109,13 +109,13 @@ static void dw_edma_debugfs_create_x32(const struct dw_edma_debugfs_entry ini[],
 	for (i = 0; i < nr_entries; i++) {
 		entries[i] = ini[i];
 
-		debugfs_create_file_unsafe(entries[i].name, 0444, dir,
+		debugfs_create_file_unsafe(entries[i].name, 0444, dent,
 					   &entries[i], &fops_x32);
 	}
 }
 
 static void dw_edma_debugfs_regs_ch(struct dw_edma_v0_ch_regs __iomem *regs,
-				    struct dentry *dir)
+				    struct dentry *dent)
 {
 	const struct dw_edma_debugfs_entry debugfs_regs[] = {
 		REGISTER(ch_control1),
@@ -131,10 +131,10 @@ static void dw_edma_debugfs_regs_ch(struct dw_edma_v0_ch_regs __iomem *regs,
 	int nr_entries;
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
-	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, dir);
+	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, dent);
 }
 
-static void dw_edma_debugfs_regs_wr(struct dentry *dir)
+static void dw_edma_debugfs_regs_wr(struct dentry *dent)
 {
 	const struct dw_edma_debugfs_entry debugfs_regs[] = {
 		/* eDMA global registers */
@@ -171,34 +171,34 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dir)
 		WR_REGISTER_UNROLL(ch6_pwr_en),
 		WR_REGISTER_UNROLL(ch7_pwr_en),
 	};
-	struct dentry *regs_dir, *ch_dir;
+	struct dentry *regs_dent, *ch_dent;
 	int nr_entries, i;
 	char name[16];
 
-	regs_dir = debugfs_create_dir(WRITE_STR, dir);
+	regs_dent = debugfs_create_dir(WRITE_STR, dent);
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
-	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
+	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dent);
 
 	if (dw->chip->mf == EDMA_MF_HDMA_COMPAT) {
 		nr_entries = ARRAY_SIZE(debugfs_unroll_regs);
 		dw_edma_debugfs_create_x32(debugfs_unroll_regs, nr_entries,
-					   regs_dir);
+					   regs_dent);
 	}
 
 	for (i = 0; i < dw->wr_ch_cnt; i++) {
 		snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
 
-		ch_dir = debugfs_create_dir(name, regs_dir);
+		ch_dent = debugfs_create_dir(name, regs_dent);
 
-		dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].wr, ch_dir);
+		dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].wr, ch_dent);
 
 		lim[0][i].start = &regs->type.unroll.ch[i].wr;
 		lim[0][i].end = &regs->type.unroll.ch[i].padding_1[0];
 	}
 }
 
-static void dw_edma_debugfs_regs_rd(struct dentry *dir)
+static void dw_edma_debugfs_regs_rd(struct dentry *dent)
 {
 	const struct dw_edma_debugfs_entry debugfs_regs[] = {
 		/* eDMA global registers */
@@ -236,27 +236,27 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dir)
 		RD_REGISTER_UNROLL(ch6_pwr_en),
 		RD_REGISTER_UNROLL(ch7_pwr_en),
 	};
-	struct dentry *regs_dir, *ch_dir;
+	struct dentry *regs_dent, *ch_dent;
 	int nr_entries, i;
 	char name[16];
 
-	regs_dir = debugfs_create_dir(READ_STR, dir);
+	regs_dent = debugfs_create_dir(READ_STR, dent);
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
-	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
+	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dent);
 
 	if (dw->chip->mf == EDMA_MF_HDMA_COMPAT) {
 		nr_entries = ARRAY_SIZE(debugfs_unroll_regs);
 		dw_edma_debugfs_create_x32(debugfs_unroll_regs, nr_entries,
-					   regs_dir);
+					   regs_dent);
 	}
 
 	for (i = 0; i < dw->rd_ch_cnt; i++) {
 		snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
 
-		ch_dir = debugfs_create_dir(name, regs_dir);
+		ch_dent = debugfs_create_dir(name, regs_dent);
 
-		dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].rd, ch_dir);
+		dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].rd, ch_dent);
 
 		lim[1][i].start = &regs->type.unroll.ch[i].rd;
 		lim[1][i].end = &regs->type.unroll.ch[i].padding_2[0];
@@ -269,16 +269,16 @@ static void dw_edma_debugfs_regs(void)
 		REGISTER(ctrl_data_arb_prior),
 		REGISTER(ctrl),
 	};
-	struct dentry *regs_dir;
+	struct dentry *regs_dent;
 	int nr_entries;
 
-	regs_dir = debugfs_create_dir(REGISTERS_STR, dw->debugfs);
+	regs_dent = debugfs_create_dir(REGISTERS_STR, dw->debugfs);
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
-	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
+	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dent);
 
-	dw_edma_debugfs_regs_wr(regs_dir);
-	dw_edma_debugfs_regs_rd(regs_dir);
+	dw_edma_debugfs_regs_wr(regs_dent);
+	dw_edma_debugfs_regs_rd(regs_dent);
 }
 
 void dw_edma_v0_debugfs_on(struct dw_edma *_dw)
-- 
2.38.0

[PATCH v6 15/24] dmaengine: dw-edma: Simplify the DebugFS context CSRs init procedure

[Serge Semin]

DW eDMA v4.70a and older have the read and write channels context CSRs
indirectly accessible. It means the CSRs like Channel Control, Xfer size,
SAR, DAR and LLP address are accessed over at a fixed MMIO address, but
their reference to the corresponding channel is determined by the Viewport
CSR. In order to have a coherent access to these registers the CSR IOs are
supposed to be protected with a spin-lock. DW eDMA v4.80a and newer
normally have unrolled Read/Write channel context registers. That is all
CSRs denoted before are directly mapped in the controller MMIO space.

Since both normal and viewport-based registers are exposed via the DebugFS
nodes, the original code author decided to implement an algorithm based on
the unrolled CSRs mapping with the viewport addresses recalculation if
it's required. The problem is that such implementation turned to be first
unscalable (supports a platform with only single eDMA available since a
base address statically preserved) and second needlessly overcomplicated
(it loops over all Rd/Wr context addresses and re-calculates the viewport
base address on each DebugFS node access). The algorithm can be greatly
simplified just by adding the channel ID and it's direction fields in the
eDMA DebugFS node descriptor. These new parameters can be used to find a
CSR offset within the corresponding channel registers space. The DW eDMA
DebugFS node getter afterwards will also use them in order to activate the
respective context CSRs viewport before reading data from the specified
register. In case of the unrolled version of the CSRs mapping there won't
be any spin-lock taken/released, no viewport activation as before this
modification.

Note this modification fixes the REGISTER() macros using an externally
defined local variable. The same problem with the rest of the macro will
be fixed in the next commit.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 84 +++++++++++-------------
 1 file changed, 38 insertions(+), 46 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
index 7bb3363b40e4..1596eedf35c5 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
@@ -15,9 +15,27 @@
 
 #define REGS_ADDR(name) \
 	((void __iomem *)&regs->name)
+
+#define REGS_CH_ADDR(name, _dir, _ch)						\
+	({									\
+		struct dw_edma_v0_ch_regs __iomem *__ch_regs;			\
+										\
+		if ((dw)->chip->mf == EDMA_MF_EDMA_LEGACY)			\
+			__ch_regs = &regs->type.legacy.ch;			\
+		else if (_dir == EDMA_DIR_READ)					\
+			__ch_regs = &regs->type.unroll.ch[_ch].rd;		\
+		else								\
+			__ch_regs = &regs->type.unroll.ch[_ch].wr;		\
+										\
+		(void __iomem *)&__ch_regs->name;				\
+	})
+
 #define REGISTER(name) \
 	{ #name, REGS_ADDR(name) }
 
+#define CTX_REGISTER(name, dir, ch) \
+	{ #name, REGS_CH_ADDR(name, dir, ch), dir, ch }
+
 #define WR_REGISTER(name) \
 	{ #name, REGS_ADDR(wr_##name) }
 #define RD_REGISTER(name) \
@@ -41,14 +59,11 @@
 static struct dw_edma				*dw;
 static struct dw_edma_v0_regs			__iomem *regs;
 
-static struct {
-	void					__iomem *start;
-	void					__iomem *end;
-} lim[2][EDMA_V0_MAX_NR_CH];
-
 struct dw_edma_debugfs_entry {
 	const char				*name;
 	void __iomem				*reg;
+	enum dw_edma_dir			dir;
+	u16					ch;
 };
 
 static int dw_edma_debugfs_u32_get(void *data, u64 *val)
@@ -58,33 +73,16 @@ static int dw_edma_debugfs_u32_get(void *data, u64 *val)
 
 	if (dw->chip->mf == EDMA_MF_EDMA_LEGACY &&
 	    reg >= (void __iomem *)&regs->type.legacy.ch) {
-		void __iomem *ptr = &regs->type.legacy.ch;
-		u32 viewport_sel = 0;
 		unsigned long flags;
-		u16 ch;
-
-		for (ch = 0; ch < dw->wr_ch_cnt; ch++)
-			if (lim[0][ch].start >= reg && reg < lim[0][ch].end) {
-				ptr += (reg - lim[0][ch].start);
-				goto legacy_sel_wr;
-			}
-
-		for (ch = 0; ch < dw->rd_ch_cnt; ch++)
-			if (lim[1][ch].start >= reg && reg < lim[1][ch].end) {
-				ptr += (reg - lim[1][ch].start);
-				goto legacy_sel_rd;
-			}
-
-		return 0;
-legacy_sel_rd:
-		viewport_sel = BIT(31);
-legacy_sel_wr:
-		viewport_sel |= FIELD_PREP(EDMA_V0_VIEWPORT_MASK, ch);
+		u32 viewport_sel;
+
+		viewport_sel = entry->dir == EDMA_DIR_READ ? BIT(31) : 0;
+		viewport_sel |= FIELD_PREP(EDMA_V0_VIEWPORT_MASK, entry->ch);
 
 		raw_spin_lock_irqsave(&dw->lock, flags);
 
 		writel(viewport_sel, &regs->type.legacy.viewport_sel);
-		*val = readl(ptr);
+		*val = readl(reg);
 
 		raw_spin_unlock_irqrestore(&dw->lock, flags);
 	} else {
@@ -114,19 +112,19 @@ static void dw_edma_debugfs_create_x32(const struct dw_edma_debugfs_entry ini[],
 	}
 }
 
-static void dw_edma_debugfs_regs_ch(struct dw_edma_v0_ch_regs __iomem *regs,
+static void dw_edma_debugfs_regs_ch(enum dw_edma_dir dir, u16 ch,
 				    struct dentry *dent)
 {
-	const struct dw_edma_debugfs_entry debugfs_regs[] = {
-		REGISTER(ch_control1),
-		REGISTER(ch_control2),
-		REGISTER(transfer_size),
-		REGISTER(sar.lsb),
-		REGISTER(sar.msb),
-		REGISTER(dar.lsb),
-		REGISTER(dar.msb),
-		REGISTER(llp.lsb),
-		REGISTER(llp.msb),
+	struct dw_edma_debugfs_entry debugfs_regs[] = {
+		CTX_REGISTER(ch_control1, dir, ch),
+		CTX_REGISTER(ch_control2, dir, ch),
+		CTX_REGISTER(transfer_size, dir, ch),
+		CTX_REGISTER(sar.lsb, dir, ch),
+		CTX_REGISTER(sar.msb, dir, ch),
+		CTX_REGISTER(dar.lsb, dir, ch),
+		CTX_REGISTER(dar.msb, dir, ch),
+		CTX_REGISTER(llp.lsb, dir, ch),
+		CTX_REGISTER(llp.msb, dir, ch),
 	};
 	int nr_entries;
 
@@ -191,10 +189,7 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dent)
 
 		ch_dent = debugfs_create_dir(name, regs_dent);
 
-		dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].wr, ch_dent);
-
-		lim[0][i].start = &regs->type.unroll.ch[i].wr;
-		lim[0][i].end = &regs->type.unroll.ch[i].padding_1[0];
+		dw_edma_debugfs_regs_ch(EDMA_DIR_WRITE, i, ch_dent);
 	}
 }
 
@@ -256,10 +251,7 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dent)
 
 		ch_dent = debugfs_create_dir(name, regs_dent);
 
-		dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].rd, ch_dent);
-
-		lim[1][i].start = &regs->type.unroll.ch[i].rd;
-		lim[1][i].end = &regs->type.unroll.ch[i].padding_2[0];
+		dw_edma_debugfs_regs_ch(EDMA_DIR_READ, i, ch_dent);
 	}
 }
 
-- 
2.38.0

[PATCH v6 16/24] dmaengine: dw-edma: Move eDMA data pointer to DebugFS node descriptor

[Serge Semin]

The last thing that really stops the DebugFS part of the eDMA driver from
supporting the multi-eDMA platform in is keeping the eDMA private data
pointer in the static area of the DebugFS module. Since the DebugFS node
descriptors are now kz-allocated we can freely move that pointer to being
preserved in the descriptors. After the DebugFS initialization procedure
that pointer will be used in the DebugFS files getter to access the common
CSRs space and the context CSRs spin-lock. So the main part of this change
is connected with the DebugFS nodes descriptors initialization macros,
which aside with already defined prototypes now require to have the DW
eDMA private data pointer passed.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 242 +++++++++++------------
 1 file changed, 117 insertions(+), 125 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
index 1596eedf35c5..e6cf608d121b 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
@@ -13,53 +13,55 @@
 #include "dw-edma-v0-regs.h"
 #include "dw-edma-core.h"
 
-#define REGS_ADDR(name) \
-	((void __iomem *)&regs->name)
+#define REGS_ADDR(dw, name)							\
+	({									\
+		struct dw_edma_v0_regs __iomem *__regs = (dw)->chip->reg_base;	\
+										\
+		(void __iomem *)&__regs->name;					\
+	})
 
-#define REGS_CH_ADDR(name, _dir, _ch)						\
+#define REGS_CH_ADDR(dw, name, _dir, _ch)					\
 	({									\
 		struct dw_edma_v0_ch_regs __iomem *__ch_regs;			\
 										\
 		if ((dw)->chip->mf == EDMA_MF_EDMA_LEGACY)			\
-			__ch_regs = &regs->type.legacy.ch;			\
+			__ch_regs = REGS_ADDR(dw, type.legacy.ch);		\
 		else if (_dir == EDMA_DIR_READ)					\
-			__ch_regs = &regs->type.unroll.ch[_ch].rd;		\
+			__ch_regs = REGS_ADDR(dw, type.unroll.ch[_ch].rd);	\
 		else								\
-			__ch_regs = &regs->type.unroll.ch[_ch].wr;		\
+			__ch_regs = REGS_ADDR(dw, type.unroll.ch[_ch].wr);	\
 										\
 		(void __iomem *)&__ch_regs->name;				\
 	})
 
-#define REGISTER(name) \
-	{ #name, REGS_ADDR(name) }
+#define REGISTER(dw, name) \
+	{ dw, #name, REGS_ADDR(dw, name) }
 
-#define CTX_REGISTER(name, dir, ch) \
-	{ #name, REGS_CH_ADDR(name, dir, ch), dir, ch }
+#define CTX_REGISTER(dw, name, dir, ch) \
+	{ dw, #name, REGS_CH_ADDR(dw, name, dir, ch), dir, ch }
 
-#define WR_REGISTER(name) \
-	{ #name, REGS_ADDR(wr_##name) }
-#define RD_REGISTER(name) \
-	{ #name, REGS_ADDR(rd_##name) }
+#define WR_REGISTER(dw, name) \
+	{ dw, #name, REGS_ADDR(dw, wr_##name) }
+#define RD_REGISTER(dw, name) \
+	{ dw, #name, REGS_ADDR(dw, rd_##name) }
 
-#define WR_REGISTER_LEGACY(name) \
-	{ #name, REGS_ADDR(type.legacy.wr_##name) }
+#define WR_REGISTER_LEGACY(dw, name) \
+	{ dw, #name, REGS_ADDR(dw, type.legacy.wr_##name) }
 #define RD_REGISTER_LEGACY(name) \
-	{ #name, REGS_ADDR(type.legacy.rd_##name) }
+	{ dw, #name, REGS_ADDR(dw, type.legacy.rd_##name) }
 
-#define WR_REGISTER_UNROLL(name) \
-	{ #name, REGS_ADDR(type.unroll.wr_##name) }
-#define RD_REGISTER_UNROLL(name) \
-	{ #name, REGS_ADDR(type.unroll.rd_##name) }
+#define WR_REGISTER_UNROLL(dw, name) \
+	{ dw, #name, REGS_ADDR(dw, type.unroll.wr_##name) }
+#define RD_REGISTER_UNROLL(dw, name) \
+	{ dw, #name, REGS_ADDR(dw, type.unroll.rd_##name) }
 
 #define WRITE_STR				"write"
 #define READ_STR				"read"
 #define CHANNEL_STR				"channel"
 #define REGISTERS_STR				"registers"
 
-static struct dw_edma				*dw;
-static struct dw_edma_v0_regs			__iomem *regs;
-
 struct dw_edma_debugfs_entry {
+	struct dw_edma				*dw;
 	const char				*name;
 	void __iomem				*reg;
 	enum dw_edma_dir			dir;
@@ -69,10 +71,11 @@ struct dw_edma_debugfs_entry {
 static int dw_edma_debugfs_u32_get(void *data, u64 *val)
 {
 	struct dw_edma_debugfs_entry *entry = data;
+	struct dw_edma *dw = entry->dw;
 	void __iomem *reg = entry->reg;
 
 	if (dw->chip->mf == EDMA_MF_EDMA_LEGACY &&
-	    reg >= (void __iomem *)&regs->type.legacy.ch) {
+	    reg >= REGS_ADDR(dw, type.legacy.ch)) {
 		unsigned long flags;
 		u32 viewport_sel;
 
@@ -81,7 +84,7 @@ static int dw_edma_debugfs_u32_get(void *data, u64 *val)
 
 		raw_spin_lock_irqsave(&dw->lock, flags);
 
-		writel(viewport_sel, &regs->type.legacy.viewport_sel);
+		writel(viewport_sel, REGS_ADDR(dw, type.legacy.viewport_sel));
 		*val = readl(reg);
 
 		raw_spin_unlock_irqrestore(&dw->lock, flags);
@@ -93,7 +96,8 @@ static int dw_edma_debugfs_u32_get(void *data, u64 *val)
 }
 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, dw_edma_debugfs_u32_get, NULL, "0x%08llx\n");
 
-static void dw_edma_debugfs_create_x32(const struct dw_edma_debugfs_entry ini[],
+static void dw_edma_debugfs_create_x32(struct dw_edma *dw,
+				       const struct dw_edma_debugfs_entry ini[],
 				       int nr_entries, struct dentry *dent)
 {
 	struct dw_edma_debugfs_entry *entries;
@@ -112,62 +116,62 @@ static void dw_edma_debugfs_create_x32(const struct dw_edma_debugfs_entry ini[],
 	}
 }
 
-static void dw_edma_debugfs_regs_ch(enum dw_edma_dir dir, u16 ch,
-				    struct dentry *dent)
+static void dw_edma_debugfs_regs_ch(struct dw_edma *dw, enum dw_edma_dir dir,
+				    u16 ch, struct dentry *dent)
 {
 	struct dw_edma_debugfs_entry debugfs_regs[] = {
-		CTX_REGISTER(ch_control1, dir, ch),
-		CTX_REGISTER(ch_control2, dir, ch),
-		CTX_REGISTER(transfer_size, dir, ch),
-		CTX_REGISTER(sar.lsb, dir, ch),
-		CTX_REGISTER(sar.msb, dir, ch),
-		CTX_REGISTER(dar.lsb, dir, ch),
-		CTX_REGISTER(dar.msb, dir, ch),
-		CTX_REGISTER(llp.lsb, dir, ch),
-		CTX_REGISTER(llp.msb, dir, ch),
+		CTX_REGISTER(dw, ch_control1, dir, ch),
+		CTX_REGISTER(dw, ch_control2, dir, ch),
+		CTX_REGISTER(dw, transfer_size, dir, ch),
+		CTX_REGISTER(dw, sar.lsb, dir, ch),
+		CTX_REGISTER(dw, sar.msb, dir, ch),
+		CTX_REGISTER(dw, dar.lsb, dir, ch),
+		CTX_REGISTER(dw, dar.msb, dir, ch),
+		CTX_REGISTER(dw, llp.lsb, dir, ch),
+		CTX_REGISTER(dw, llp.msb, dir, ch),
 	};
 	int nr_entries;
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
-	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, dent);
+	dw_edma_debugfs_create_x32(dw, debugfs_regs, nr_entries, dent);
 }
 
-static void dw_edma_debugfs_regs_wr(struct dentry *dent)
+static void dw_edma_debugfs_regs_wr(struct dw_edma *dw, struct dentry *dent)
 {
 	const struct dw_edma_debugfs_entry debugfs_regs[] = {
 		/* eDMA global registers */
-		WR_REGISTER(engine_en),
-		WR_REGISTER(doorbell),
-		WR_REGISTER(ch_arb_weight.lsb),
-		WR_REGISTER(ch_arb_weight.msb),
+		WR_REGISTER(dw, engine_en),
+		WR_REGISTER(dw, doorbell),
+		WR_REGISTER(dw, ch_arb_weight.lsb),
+		WR_REGISTER(dw, ch_arb_weight.msb),
 		/* eDMA interrupts registers */
-		WR_REGISTER(int_status),
-		WR_REGISTER(int_mask),
-		WR_REGISTER(int_clear),
-		WR_REGISTER(err_status),
-		WR_REGISTER(done_imwr.lsb),
-		WR_REGISTER(done_imwr.msb),
-		WR_REGISTER(abort_imwr.lsb),
-		WR_REGISTER(abort_imwr.msb),
-		WR_REGISTER(ch01_imwr_data),
-		WR_REGISTER(ch23_imwr_data),
-		WR_REGISTER(ch45_imwr_data),
-		WR_REGISTER(ch67_imwr_data),
-		WR_REGISTER(linked_list_err_en),
+		WR_REGISTER(dw, int_status),
+		WR_REGISTER(dw, int_mask),
+		WR_REGISTER(dw, int_clear),
+		WR_REGISTER(dw, err_status),
+		WR_REGISTER(dw, done_imwr.lsb),
+		WR_REGISTER(dw, done_imwr.msb),
+		WR_REGISTER(dw, abort_imwr.lsb),
+		WR_REGISTER(dw, abort_imwr.msb),
+		WR_REGISTER(dw, ch01_imwr_data),
+		WR_REGISTER(dw, ch23_imwr_data),
+		WR_REGISTER(dw, ch45_imwr_data),
+		WR_REGISTER(dw, ch67_imwr_data),
+		WR_REGISTER(dw, linked_list_err_en),
 	};
 	const struct dw_edma_debugfs_entry debugfs_unroll_regs[] = {
 		/* eDMA channel context grouping */
-		WR_REGISTER_UNROLL(engine_chgroup),
-		WR_REGISTER_UNROLL(engine_hshake_cnt.lsb),
-		WR_REGISTER_UNROLL(engine_hshake_cnt.msb),
-		WR_REGISTER_UNROLL(ch0_pwr_en),
-		WR_REGISTER_UNROLL(ch1_pwr_en),
-		WR_REGISTER_UNROLL(ch2_pwr_en),
-		WR_REGISTER_UNROLL(ch3_pwr_en),
-		WR_REGISTER_UNROLL(ch4_pwr_en),
-		WR_REGISTER_UNROLL(ch5_pwr_en),
-		WR_REGISTER_UNROLL(ch6_pwr_en),
-		WR_REGISTER_UNROLL(ch7_pwr_en),
+		WR_REGISTER_UNROLL(dw, engine_chgroup),
+		WR_REGISTER_UNROLL(dw, engine_hshake_cnt.lsb),
+		WR_REGISTER_UNROLL(dw, engine_hshake_cnt.msb),
+		WR_REGISTER_UNROLL(dw, ch0_pwr_en),
+		WR_REGISTER_UNROLL(dw, ch1_pwr_en),
+		WR_REGISTER_UNROLL(dw, ch2_pwr_en),
+		WR_REGISTER_UNROLL(dw, ch3_pwr_en),
+		WR_REGISTER_UNROLL(dw, ch4_pwr_en),
+		WR_REGISTER_UNROLL(dw, ch5_pwr_en),
+		WR_REGISTER_UNROLL(dw, ch6_pwr_en),
+		WR_REGISTER_UNROLL(dw, ch7_pwr_en),
 	};
 	struct dentry *regs_dent, *ch_dent;
 	int nr_entries, i;
@@ -176,11 +180,11 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dent)
 	regs_dent = debugfs_create_dir(WRITE_STR, dent);
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
-	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dent);
+	dw_edma_debugfs_create_x32(dw, debugfs_regs, nr_entries, regs_dent);
 
 	if (dw->chip->mf == EDMA_MF_HDMA_COMPAT) {
 		nr_entries = ARRAY_SIZE(debugfs_unroll_regs);
-		dw_edma_debugfs_create_x32(debugfs_unroll_regs, nr_entries,
+		dw_edma_debugfs_create_x32(dw, debugfs_unroll_regs, nr_entries,
 					   regs_dent);
 	}
 
@@ -189,47 +193,47 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dent)
 
 		ch_dent = debugfs_create_dir(name, regs_dent);
 
-		dw_edma_debugfs_regs_ch(EDMA_DIR_WRITE, i, ch_dent);
+		dw_edma_debugfs_regs_ch(dw, EDMA_DIR_WRITE, i, ch_dent);
 	}
 }
 
-static void dw_edma_debugfs_regs_rd(struct dentry *dent)
+static void dw_edma_debugfs_regs_rd(struct dw_edma *dw, struct dentry *dent)
 {
 	const struct dw_edma_debugfs_entry debugfs_regs[] = {
 		/* eDMA global registers */
-		RD_REGISTER(engine_en),
-		RD_REGISTER(doorbell),
-		RD_REGISTER(ch_arb_weight.lsb),
-		RD_REGISTER(ch_arb_weight.msb),
+		RD_REGISTER(dw, engine_en),
+		RD_REGISTER(dw, doorbell),
+		RD_REGISTER(dw, ch_arb_weight.lsb),
+		RD_REGISTER(dw, ch_arb_weight.msb),
 		/* eDMA interrupts registers */
-		RD_REGISTER(int_status),
-		RD_REGISTER(int_mask),
-		RD_REGISTER(int_clear),
-		RD_REGISTER(err_status.lsb),
-		RD_REGISTER(err_status.msb),
-		RD_REGISTER(linked_list_err_en),
-		RD_REGISTER(done_imwr.lsb),
-		RD_REGISTER(done_imwr.msb),
-		RD_REGISTER(abort_imwr.lsb),
-		RD_REGISTER(abort_imwr.msb),
-		RD_REGISTER(ch01_imwr_data),
-		RD_REGISTER(ch23_imwr_data),
-		RD_REGISTER(ch45_imwr_data),
-		RD_REGISTER(ch67_imwr_data),
+		RD_REGISTER(dw, int_status),
+		RD_REGISTER(dw, int_mask),
+		RD_REGISTER(dw, int_clear),
+		RD_REGISTER(dw, err_status.lsb),
+		RD_REGISTER(dw, err_status.msb),
+		RD_REGISTER(dw, linked_list_err_en),
+		RD_REGISTER(dw, done_imwr.lsb),
+		RD_REGISTER(dw, done_imwr.msb),
+		RD_REGISTER(dw, abort_imwr.lsb),
+		RD_REGISTER(dw, abort_imwr.msb),
+		RD_REGISTER(dw, ch01_imwr_data),
+		RD_REGISTER(dw, ch23_imwr_data),
+		RD_REGISTER(dw, ch45_imwr_data),
+		RD_REGISTER(dw, ch67_imwr_data),
 	};
 	const struct dw_edma_debugfs_entry debugfs_unroll_regs[] = {
 		/* eDMA channel context grouping */
-		RD_REGISTER_UNROLL(engine_chgroup),
-		RD_REGISTER_UNROLL(engine_hshake_cnt.lsb),
-		RD_REGISTER_UNROLL(engine_hshake_cnt.msb),
-		RD_REGISTER_UNROLL(ch0_pwr_en),
-		RD_REGISTER_UNROLL(ch1_pwr_en),
-		RD_REGISTER_UNROLL(ch2_pwr_en),
-		RD_REGISTER_UNROLL(ch3_pwr_en),
-		RD_REGISTER_UNROLL(ch4_pwr_en),
-		RD_REGISTER_UNROLL(ch5_pwr_en),
-		RD_REGISTER_UNROLL(ch6_pwr_en),
-		RD_REGISTER_UNROLL(ch7_pwr_en),
+		RD_REGISTER_UNROLL(dw, engine_chgroup),
+		RD_REGISTER_UNROLL(dw, engine_hshake_cnt.lsb),
+		RD_REGISTER_UNROLL(dw, engine_hshake_cnt.msb),
+		RD_REGISTER_UNROLL(dw, ch0_pwr_en),
+		RD_REGISTER_UNROLL(dw, ch1_pwr_en),
+		RD_REGISTER_UNROLL(dw, ch2_pwr_en),
+		RD_REGISTER_UNROLL(dw, ch3_pwr_en),
+		RD_REGISTER_UNROLL(dw, ch4_pwr_en),
+		RD_REGISTER_UNROLL(dw, ch5_pwr_en),
+		RD_REGISTER_UNROLL(dw, ch6_pwr_en),
+		RD_REGISTER_UNROLL(dw, ch7_pwr_en),
 	};
 	struct dentry *regs_dent, *ch_dent;
 	int nr_entries, i;
@@ -238,11 +242,11 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dent)
 	regs_dent = debugfs_create_dir(READ_STR, dent);
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
-	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dent);
+	dw_edma_debugfs_create_x32(dw, debugfs_regs, nr_entries, regs_dent);
 
 	if (dw->chip->mf == EDMA_MF_HDMA_COMPAT) {
 		nr_entries = ARRAY_SIZE(debugfs_unroll_regs);
-		dw_edma_debugfs_create_x32(debugfs_unroll_regs, nr_entries,
+		dw_edma_debugfs_create_x32(dw, debugfs_unroll_regs, nr_entries,
 					   regs_dent);
 	}
 
@@ -251,15 +255,15 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dent)
 
 		ch_dent = debugfs_create_dir(name, regs_dent);
 
-		dw_edma_debugfs_regs_ch(EDMA_DIR_READ, i, ch_dent);
+		dw_edma_debugfs_regs_ch(dw, EDMA_DIR_READ, i, ch_dent);
 	}
 }
 
-static void dw_edma_debugfs_regs(void)
+static void dw_edma_debugfs_regs(struct dw_edma *dw)
 {
 	const struct dw_edma_debugfs_entry debugfs_regs[] = {
-		REGISTER(ctrl_data_arb_prior),
-		REGISTER(ctrl),
+		REGISTER(dw, ctrl_data_arb_prior),
+		REGISTER(dw, ctrl),
 	};
 	struct dentry *regs_dent;
 	int nr_entries;
@@ -267,40 +271,28 @@ static void dw_edma_debugfs_regs(void)
 	regs_dent = debugfs_create_dir(REGISTERS_STR, dw->debugfs);
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
-	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dent);
+	dw_edma_debugfs_create_x32(dw, debugfs_regs, nr_entries, regs_dent);
 
-	dw_edma_debugfs_regs_wr(regs_dent);
-	dw_edma_debugfs_regs_rd(regs_dent);
+	dw_edma_debugfs_regs_wr(dw, regs_dent);
+	dw_edma_debugfs_regs_rd(dw, regs_dent);
 }
 
-void dw_edma_v0_debugfs_on(struct dw_edma *_dw)
+void dw_edma_v0_debugfs_on(struct dw_edma *dw)
 {
 	if (!debugfs_initialized())
 		return;
 
-	dw = _dw;
-	if (!dw)
-		return;
-
-	regs = dw->chip->reg_base;
-	if (!regs)
-		return;
-
 	dw->debugfs = debugfs_create_dir(dw->name, NULL);
 
 	debugfs_create_u32("mf", 0444, dw->debugfs, &dw->chip->mf);
 	debugfs_create_u16("wr_ch_cnt", 0444, dw->debugfs, &dw->wr_ch_cnt);
 	debugfs_create_u16("rd_ch_cnt", 0444, dw->debugfs, &dw->rd_ch_cnt);
 
-	dw_edma_debugfs_regs();
+	dw_edma_debugfs_regs(dw);
 }
 
-void dw_edma_v0_debugfs_off(struct dw_edma *_dw)
+void dw_edma_v0_debugfs_off(struct dw_edma *dw)
 {
-	dw = _dw;
-	if (!dw)
-		return;
-
 	debugfs_remove_recursive(dw->debugfs);
 	dw->debugfs = NULL;
 }
-- 
2.38.0

[PATCH v6 17/24] dmaengine: dw-edma: Join Write/Read channels into a single device

[Serge Semin]

Indeed there is no point in such split up because due to multiple reasons.
First of all eDMA read and write channels belong to one physical
controller. Splitting them up illogical. Secondly the channels
differentiating can be done by means of the filtering and the
dma_get_slave_caps() method. Finally having these channels handled
separately not only needlessly complicates the code, but also causes the
DebugFS error printed to console:

>> Debugfs: Directory '1f052000.pcie' with parent 'dmaengine' already present!

So to speak let's join the read/write channels into a single DMA device.
The client drivers will be able to choose the channel with required
capability by getting the DMA slave direction setting. It's default value
is overridden by the dw_edma_device_caps() callback in accordance with the
channel nature.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-core.c | 116 +++++++++++++++--------------
 drivers/dma/dw-edma/dw-edma-core.h |   5 +-
 2 files changed, 61 insertions(+), 60 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index ecd3e8f7ac5d..c3ecae4287d0 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -208,6 +208,24 @@ static void dw_edma_start_transfer(struct dw_edma_chan *chan)
 	desc->chunks_alloc--;
 }
 
+static void dw_edma_device_caps(struct dma_chan *dchan,
+				struct dma_slave_caps *caps)
+{
+	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
+
+	if (chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) {
+		if (chan->dir == EDMA_DIR_READ)
+			caps->directions = BIT(DMA_DEV_TO_MEM);
+		else
+			caps->directions = BIT(DMA_MEM_TO_DEV);
+	} else {
+		if (chan->dir == EDMA_DIR_WRITE)
+			caps->directions = BIT(DMA_DEV_TO_MEM);
+		else
+			caps->directions = BIT(DMA_MEM_TO_DEV);
+	}
+}
+
 static int dw_edma_device_config(struct dma_chan *dchan,
 				 struct dma_slave_config *config)
 {
@@ -717,8 +735,7 @@ static void dw_edma_free_chan_resources(struct dma_chan *dchan)
 	}
 }
 
-static int dw_edma_channel_setup(struct dw_edma *dw, bool write,
-				 u32 wr_alloc, u32 rd_alloc)
+static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)
 {
 	struct dw_edma_chip *chip = dw->chip;
 	struct dw_edma_region *dt_region;
@@ -726,27 +743,15 @@ static int dw_edma_channel_setup(struct dw_edma *dw, bool write,
 	struct dw_edma_chan *chan;
 	struct dw_edma_irq *irq;
 	struct dma_device *dma;
-	u32 alloc, off_alloc;
-	u32 i, j, cnt;
-	int err = 0;
+	u32 i, ch_cnt;
 	u32 pos;
 
-	if (write) {
-		i = 0;
-		cnt = dw->wr_ch_cnt;
-		dma = &dw->wr_edma;
-		alloc = wr_alloc;
-		off_alloc = 0;
-	} else {
-		i = dw->wr_ch_cnt;
-		cnt = dw->rd_ch_cnt;
-		dma = &dw->rd_edma;
-		alloc = rd_alloc;
-		off_alloc = wr_alloc;
-	}
+	ch_cnt = dw->wr_ch_cnt + dw->rd_ch_cnt;
+	dma = &dw->dma;
 
 	INIT_LIST_HEAD(&dma->channels);
-	for (j = 0; (alloc || dw->nr_irqs == 1) && j < cnt; j++, i++) {
+
+	for (i = 0; i < ch_cnt; i++) {
 		chan = &dw->chan[i];
 
 		dt_region = devm_kzalloc(dev, sizeof(*dt_region), GFP_KERNEL);
@@ -756,52 +761,62 @@ static int dw_edma_channel_setup(struct dw_edma *dw, bool write,
 		chan->vc.chan.private = dt_region;
 
 		chan->dw = dw;
-		chan->id = j;
-		chan->dir = write ? EDMA_DIR_WRITE : EDMA_DIR_READ;
+
+		if (i < dw->wr_ch_cnt) {
+			chan->id = i;
+			chan->dir = EDMA_DIR_WRITE;
+		} else {
+			chan->id = i - dw->wr_ch_cnt;
+			chan->dir = EDMA_DIR_READ;
+		}
+
 		chan->configured = false;
 		chan->request = EDMA_REQ_NONE;
 		chan->status = EDMA_ST_IDLE;
 
-		if (write)
-			chan->ll_max = (chip->ll_region_wr[j].sz / EDMA_LL_SZ);
+		if (chan->dir == EDMA_DIR_WRITE)
+			chan->ll_max = (chip->ll_region_wr[chan->id].sz / EDMA_LL_SZ);
 		else
-			chan->ll_max = (chip->ll_region_rd[j].sz / EDMA_LL_SZ);
+			chan->ll_max = (chip->ll_region_rd[chan->id].sz / EDMA_LL_SZ);
 		chan->ll_max -= 1;
 
 		dev_vdbg(dev, "L. List:\tChannel %s[%u] max_cnt=%u\n",
-			 write ? "write" : "read", j, chan->ll_max);
+			 chan->dir == EDMA_DIR_WRITE ? "write" : "read",
+			 chan->id, chan->ll_max);
 
 		if (dw->nr_irqs == 1)
 			pos = 0;
+		else if (chan->dir == EDMA_DIR_WRITE)
+			pos = chan->id % wr_alloc;
 		else
-			pos = off_alloc + (j % alloc);
+			pos = wr_alloc + chan->id % rd_alloc;
 
 		irq = &dw->irq[pos];
 
-		if (write)
-			irq->wr_mask |= BIT(j);
+		if (chan->dir == EDMA_DIR_WRITE)
+			irq->wr_mask |= BIT(chan->id);
 		else
-			irq->rd_mask |= BIT(j);
+			irq->rd_mask |= BIT(chan->id);
 
 		irq->dw = dw;
 		memcpy(&chan->msi, &irq->msi, sizeof(chan->msi));
 
 		dev_vdbg(dev, "MSI:\t\tChannel %s[%u] addr=0x%.8x%.8x, data=0x%.8x\n",
-			 write ? "write" : "read", j,
+			 chan->dir == EDMA_DIR_WRITE  ? "write" : "read", chan->id,
 			 chan->msi.address_hi, chan->msi.address_lo,
 			 chan->msi.data);
 
 		chan->vc.desc_free = vchan_free_desc;
 		vchan_init(&chan->vc, dma);
 
-		if (write) {
-			dt_region->paddr = chip->dt_region_wr[j].paddr;
-			dt_region->vaddr = chip->dt_region_wr[j].vaddr;
-			dt_region->sz = chip->dt_region_wr[j].sz;
+		if (chan->dir == EDMA_DIR_WRITE) {
+			dt_region->paddr = chip->dt_region_wr[chan->id].paddr;
+			dt_region->vaddr = chip->dt_region_wr[chan->id].vaddr;
+			dt_region->sz = chip->dt_region_wr[chan->id].sz;
 		} else {
-			dt_region->paddr = chip->dt_region_rd[j].paddr;
-			dt_region->vaddr = chip->dt_region_rd[j].vaddr;
-			dt_region->sz = chip->dt_region_rd[j].sz;
+			dt_region->paddr = chip->dt_region_rd[chan->id].paddr;
+			dt_region->vaddr = chip->dt_region_rd[chan->id].vaddr;
+			dt_region->sz = chip->dt_region_rd[chan->id].sz;
 		}
 
 		dw_edma_v0_core_device_config(chan);
@@ -813,7 +828,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, bool write,
 	dma_cap_set(DMA_CYCLIC, dma->cap_mask);
 	dma_cap_set(DMA_PRIVATE, dma->cap_mask);
 	dma_cap_set(DMA_INTERLEAVE, dma->cap_mask);
-	dma->directions = BIT(write ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV);
+	dma->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
 	dma->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
 	dma->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
 	dma->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
@@ -822,6 +837,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, bool write,
 	dma->dev = chip->dev;
 	dma->device_alloc_chan_resources = dw_edma_alloc_chan_resources;
 	dma->device_free_chan_resources = dw_edma_free_chan_resources;
+	dma->device_caps = dw_edma_device_caps;
 	dma->device_config = dw_edma_device_config;
 	dma->device_pause = dw_edma_device_pause;
 	dma->device_resume = dw_edma_device_resume;
@@ -835,9 +851,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, bool write,
 	dma_set_max_seg_size(dma->dev, U32_MAX);
 
 	/* Register DMA device */
-	err = dma_async_device_register(dma);
-
-	return err;
+	return dma_async_device_register(dma);
 }
 
 static inline void dw_edma_dec_irq_alloc(int *nr_irqs, u32 *alloc, u16 cnt)
@@ -982,13 +996,8 @@ int dw_edma_probe(struct dw_edma_chip *chip)
 	if (err)
 		return err;
 
-	/* Setup write channels */
-	err = dw_edma_channel_setup(dw, true, wr_alloc, rd_alloc);
-	if (err)
-		goto err_irq_free;
-
-	/* Setup read channels */
-	err = dw_edma_channel_setup(dw, false, wr_alloc, rd_alloc);
+	/* Setup write/read channels */
+	err = dw_edma_channel_setup(dw, wr_alloc, rd_alloc);
 	if (err)
 		goto err_irq_free;
 
@@ -1022,15 +1031,8 @@ int dw_edma_remove(struct dw_edma_chip *chip)
 		free_irq(chip->ops->irq_vector(dev, i), &dw->irq[i]);
 
 	/* Deregister eDMA device */
-	dma_async_device_unregister(&dw->wr_edma);
-	list_for_each_entry_safe(chan, _chan, &dw->wr_edma.channels,
-				 vc.chan.device_node) {
-		tasklet_kill(&chan->vc.task);
-		list_del(&chan->vc.chan.device_node);
-	}
-
-	dma_async_device_unregister(&dw->rd_edma);
-	list_for_each_entry_safe(chan, _chan, &dw->rd_edma.channels,
+	dma_async_device_unregister(&dw->dma);
+	list_for_each_entry_safe(chan, _chan, &dw->dma.channels,
 				 vc.chan.device_node) {
 		tasklet_kill(&chan->vc.task);
 		list_del(&chan->vc.chan.device_node);
diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h
index 85df2d511907..b576a8fff45a 100644
--- a/drivers/dma/dw-edma/dw-edma-core.h
+++ b/drivers/dma/dw-edma/dw-edma-core.h
@@ -98,10 +98,9 @@ struct dw_edma_irq {
 struct dw_edma {
 	char				name[20];
 
-	struct dma_device		wr_edma;
-	u16				wr_ch_cnt;
+	struct dma_device		dma;
 
-	struct dma_device		rd_edma;
+	u16				wr_ch_cnt;
 	u16				rd_ch_cnt;
 
 	struct dw_edma_irq		*irq;
-- 
2.38.0

[PATCH v6 18/24] dmaengine: dw-edma: Use DMA-engine device DebugFS subdirectory

[Serge Semin]

Since all DW eDMA read and write channels are now installed in a framework
of a single DMA-engine device, we can freely move all the DW eDMA-specific
DebugFS nodes into a ready-to-use DMA-engine DebugFS subdirectory. It's
created during the DMA-device registration and can be found in the
dma_device.dbg_dev_root field.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-core.c       |  3 ---
 drivers/dma/dw-edma/dw-edma-core.h       |  3 ---
 drivers/dma/dw-edma/dw-edma-v0-core.c    |  5 -----
 drivers/dma/dw-edma/dw-edma-v0-core.h    |  1 -
 drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 16 ++++------------
 drivers/dma/dw-edma/dw-edma-v0-debugfs.h |  5 -----
 6 files changed, 4 insertions(+), 29 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index c3ecae4287d0..58808bec4148 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -1038,9 +1038,6 @@ int dw_edma_remove(struct dw_edma_chip *chip)
 		list_del(&chan->vc.chan.device_node);
 	}
 
-	/* Turn debugfs off */
-	dw_edma_v0_core_debugfs_off(dw);
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(dw_edma_remove);
diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h
index b576a8fff45a..e3ad3e372b55 100644
--- a/drivers/dma/dw-edma/dw-edma-core.h
+++ b/drivers/dma/dw-edma/dw-edma-core.h
@@ -111,9 +111,6 @@ struct dw_edma {
 	raw_spinlock_t			lock;		/* Only for legacy */
 
 	struct dw_edma_chip             *chip;
-#ifdef CONFIG_DEBUG_FS
-	struct dentry			*debugfs;
-#endif /* CONFIG_DEBUG_FS */
 };
 
 struct dw_edma_sg {
diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
index 77e6cfe52e0a..66f296daac5a 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
@@ -504,8 +504,3 @@ void dw_edma_v0_core_debugfs_on(struct dw_edma *dw)
 {
 	dw_edma_v0_debugfs_on(dw);
 }
-
-void dw_edma_v0_core_debugfs_off(struct dw_edma *dw)
-{
-	dw_edma_v0_debugfs_off(dw);
-}
diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.h b/drivers/dma/dw-edma/dw-edma-v0-core.h
index 75aec6d31b21..ab96a1f48080 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.h
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.h
@@ -23,6 +23,5 @@ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first);
 int dw_edma_v0_core_device_config(struct dw_edma_chan *chan);
 /* eDMA debug fs callbacks */
 void dw_edma_v0_core_debugfs_on(struct dw_edma *dw);
-void dw_edma_v0_core_debugfs_off(struct dw_edma *dw);
 
 #endif /* _DW_EDMA_V0_CORE_H */
diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
index e6cf608d121b..d12c607433bf 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
@@ -268,7 +268,7 @@ static void dw_edma_debugfs_regs(struct dw_edma *dw)
 	struct dentry *regs_dent;
 	int nr_entries;
 
-	regs_dent = debugfs_create_dir(REGISTERS_STR, dw->debugfs);
+	regs_dent = debugfs_create_dir(REGISTERS_STR, dw->dma.dbg_dev_root);
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
 	dw_edma_debugfs_create_x32(dw, debugfs_regs, nr_entries, regs_dent);
@@ -282,17 +282,9 @@ void dw_edma_v0_debugfs_on(struct dw_edma *dw)
 	if (!debugfs_initialized())
 		return;
 
-	dw->debugfs = debugfs_create_dir(dw->name, NULL);
-
-	debugfs_create_u32("mf", 0444, dw->debugfs, &dw->chip->mf);
-	debugfs_create_u16("wr_ch_cnt", 0444, dw->debugfs, &dw->wr_ch_cnt);
-	debugfs_create_u16("rd_ch_cnt", 0444, dw->debugfs, &dw->rd_ch_cnt);
+	debugfs_create_u32("mf", 0444, dw->dma.dbg_dev_root, &dw->chip->mf);
+	debugfs_create_u16("wr_ch_cnt", 0444, dw->dma.dbg_dev_root, &dw->wr_ch_cnt);
+	debugfs_create_u16("rd_ch_cnt", 0444, dw->dma.dbg_dev_root, &dw->rd_ch_cnt);
 
 	dw_edma_debugfs_regs(dw);
 }
-
-void dw_edma_v0_debugfs_off(struct dw_edma *dw)
-{
-	debugfs_remove_recursive(dw->debugfs);
-	dw->debugfs = NULL;
-}
diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.h b/drivers/dma/dw-edma/dw-edma-v0-debugfs.h
index 3391b86edf5a..fb3342d97d6d 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.h
+++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.h
@@ -13,15 +13,10 @@
 
 #ifdef CONFIG_DEBUG_FS
 void dw_edma_v0_debugfs_on(struct dw_edma *dw);
-void dw_edma_v0_debugfs_off(struct dw_edma *dw);
 #else
 static inline void dw_edma_v0_debugfs_on(struct dw_edma *dw)
 {
 }
-
-static inline void dw_edma_v0_debugfs_off(struct dw_edma *dw)
-{
-}
 #endif /* CONFIG_DEBUG_FS */
 
 #endif /* _DW_EDMA_V0_DEBUG_FS_H */
-- 
2.38.0

[PATCH v6 19/24] dmaengine: dw-edma: Use non-atomic io-64 methods

[Serge Semin]

Instead of splitting the 64-bits IOs up into two 32-bits ones it's
possible to use the already available non-atomic readq/writeq methods
implemented exactly for such cases. They are defined in the dedicated
header files io-64-nonatomic-lo-hi.h/io-64-nonatomic-hi-lo.h. So in case
if the 64-bits readq/writeq methods are unavailable on some platforms at
consideration, the corresponding drivers can have any of these headers
included and stop locally re-implementing the 64-bits IO accessors taking
into account the non-atomic nature of the included methods. Let's do that
in the DW eDMA driver too. Note by doing so we can discard the
CONFIG_64BIT config ifdefs from the code.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-v0-core.c | 55 +++++++++------------------
 1 file changed, 18 insertions(+), 37 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
index 66f296daac5a..51a34b43434c 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
@@ -8,6 +8,8 @@
 
 #include <linux/bitfield.h>
 
+#include <linux/io-64-nonatomic-lo-hi.h>
+
 #include "dw-edma-core.h"
 #include "dw-edma-v0-core.h"
 #include "dw-edma-v0-regs.h"
@@ -53,8 +55,6 @@ static inline struct dw_edma_v0_regs __iomem *__dw_regs(struct dw_edma *dw)
 		SET_32(dw, rd_##name, value);		\
 	} while (0)
 
-#ifdef CONFIG_64BIT
-
 #define SET_64(dw, name, value)				\
 	writeq(value, &(__dw_regs(dw)->name))
 
@@ -80,8 +80,6 @@ static inline struct dw_edma_v0_regs __iomem *__dw_regs(struct dw_edma *dw)
 		SET_64(dw, rd_##name, value);		\
 	} while (0)
 
-#endif /* CONFIG_64BIT */
-
 #define SET_COMPAT(dw, name, value)			\
 	writel(value, &(__dw_regs(dw)->type.unroll.name))
 
@@ -164,14 +162,13 @@ static inline u32 readl_ch(struct dw_edma *dw, enum dw_edma_dir dir, u16 ch,
 #define SET_LL_32(ll, value) \
 	writel(value, ll)
 
-#ifdef CONFIG_64BIT
-
 static inline void writeq_ch(struct dw_edma *dw, enum dw_edma_dir dir, u16 ch,
 			     u64 value, void __iomem *addr)
 {
+	unsigned long flags;
+
 	if (dw->chip->mf == EDMA_MF_EDMA_LEGACY) {
 		u32 viewport_sel;
-		unsigned long flags;
 
 		raw_spin_lock_irqsave(&dw->lock, flags);
 
@@ -181,22 +178,22 @@ static inline void writeq_ch(struct dw_edma *dw, enum dw_edma_dir dir, u16 ch,
 
 		writel(viewport_sel,
 		       &(__dw_regs(dw)->type.legacy.viewport_sel));
-		writeq(value, addr);
+	}
+
+	writeq(value, addr);
 
+	if (dw->chip->mf == EDMA_MF_EDMA_LEGACY)
 		raw_spin_unlock_irqrestore(&dw->lock, flags);
-	} else {
-		writeq(value, addr);
-	}
 }
 
 static inline u64 readq_ch(struct dw_edma *dw, enum dw_edma_dir dir, u16 ch,
 			   const void __iomem *addr)
 {
-	u32 value;
+	unsigned long flags;
+	u64 value;
 
 	if (dw->chip->mf == EDMA_MF_EDMA_LEGACY) {
 		u32 viewport_sel;
-		unsigned long flags;
 
 		raw_spin_lock_irqsave(&dw->lock, flags);
 
@@ -206,12 +203,12 @@ static inline u64 readq_ch(struct dw_edma *dw, enum dw_edma_dir dir, u16 ch,
 
 		writel(viewport_sel,
 		       &(__dw_regs(dw)->type.legacy.viewport_sel));
-		value = readq(addr);
+	}
+
+	value = readq(addr);
 
+	if (dw->chip->mf == EDMA_MF_EDMA_LEGACY)
 		raw_spin_unlock_irqrestore(&dw->lock, flags);
-	} else {
-		value = readq(addr);
-	}
 
 	return value;
 }
@@ -225,8 +222,6 @@ static inline u64 readq_ch(struct dw_edma *dw, enum dw_edma_dir dir, u16 ch,
 #define SET_LL_64(ll, value) \
 	writeq(value, ll)
 
-#endif /* CONFIG_64BIT */
-
 /* eDMA management callbacks */
 void dw_edma_v0_core_off(struct dw_edma *dw)
 {
@@ -325,19 +320,10 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
 		/* Transfer size */
 		SET_LL_32(&lli[i].transfer_size, child->sz);
 		/* SAR */
-		#ifdef CONFIG_64BIT
-			SET_LL_64(&lli[i].sar.reg, child->sar);
-		#else /* CONFIG_64BIT */
-			SET_LL_32(&lli[i].sar.lsb, lower_32_bits(child->sar));
-			SET_LL_32(&lli[i].sar.msb, upper_32_bits(child->sar));
-		#endif /* CONFIG_64BIT */
+		SET_LL_64(&lli[i].sar.reg, child->sar);
 		/* DAR */
-		#ifdef CONFIG_64BIT
-			SET_LL_64(&lli[i].dar.reg, child->dar);
-		#else /* CONFIG_64BIT */
-			SET_LL_32(&lli[i].dar.lsb, lower_32_bits(child->dar));
-			SET_LL_32(&lli[i].dar.msb, upper_32_bits(child->dar));
-		#endif /* CONFIG_64BIT */
+		SET_LL_64(&lli[i].dar.reg, child->dar);
+
 		i++;
 	}
 
@@ -349,12 +335,7 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
 	/* Channel control */
 	SET_LL_32(&llp->control, control);
 	/* Linked list */
-	#ifdef CONFIG_64BIT
-		SET_LL_64(&llp->llp.reg, chunk->ll_region.paddr);
-	#else /* CONFIG_64BIT */
-		SET_LL_32(&llp->llp.lsb, lower_32_bits(chunk->ll_region.paddr));
-		SET_LL_32(&llp->llp.msb, upper_32_bits(chunk->ll_region.paddr));
-	#endif /* CONFIG_64BIT */
+	SET_LL_64(&llp->llp.reg, chunk->ll_region.paddr);
 }
 
 void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
-- 
2.38.0

[PATCH v6 20/24] dmaengine: dw-edma: Drop DT-region allocation

[Serge Semin]

There is no point in allocating an additional memory for the data target
regions passed then to the client drivers. Just use the already available
structures defined in the dw_edma_chip instance.

Note these regions are unused in normal circumstances since they are
specific to the case of eDMA being embedded into the DW PCIe End-point and
having it's CSRs accessible over a End-point' BAR. This case is only known
to be implemented as a part of the Synopsys PCIe EndPoint IP prototype
kit.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-core.c | 21 ++++-----------------
 1 file changed, 4 insertions(+), 17 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 58808bec4148..040a88cfe070 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -738,7 +738,6 @@ static void dw_edma_free_chan_resources(struct dma_chan *dchan)
 static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)
 {
 	struct dw_edma_chip *chip = dw->chip;
-	struct dw_edma_region *dt_region;
 	struct device *dev = chip->dev;
 	struct dw_edma_chan *chan;
 	struct dw_edma_irq *irq;
@@ -754,12 +753,6 @@ static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)
 	for (i = 0; i < ch_cnt; i++) {
 		chan = &dw->chan[i];
 
-		dt_region = devm_kzalloc(dev, sizeof(*dt_region), GFP_KERNEL);
-		if (!dt_region)
-			return -ENOMEM;
-
-		chan->vc.chan.private = dt_region;
-
 		chan->dw = dw;
 
 		if (i < dw->wr_ch_cnt) {
@@ -807,17 +800,11 @@ static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)
 			 chan->msi.data);
 
 		chan->vc.desc_free = vchan_free_desc;
-		vchan_init(&chan->vc, dma);
+		chan->vc.chan.private = chan->dir == EDMA_DIR_WRITE ?
+					&dw->chip->dt_region_wr[chan->id] :
+					&dw->chip->dt_region_rd[chan->id];
 
-		if (chan->dir == EDMA_DIR_WRITE) {
-			dt_region->paddr = chip->dt_region_wr[chan->id].paddr;
-			dt_region->vaddr = chip->dt_region_wr[chan->id].vaddr;
-			dt_region->sz = chip->dt_region_wr[chan->id].sz;
-		} else {
-			dt_region->paddr = chip->dt_region_rd[chan->id].paddr;
-			dt_region->vaddr = chip->dt_region_rd[chan->id].vaddr;
-			dt_region->sz = chip->dt_region_rd[chan->id].sz;
-		}
+		vchan_init(&chan->vc, dma);
 
 		dw_edma_v0_core_device_config(chan);
 	}
-- 
2.38.0

[PATCH v6 21/24] dmaengine: dw-edma: Replace chip ID number with device name

[Serge Semin]

Using some abstract number as the DW eDMA chip identifier isn't really
practical. First of all there can be more than one DW eDMA controller on
the platform some of them can be detected as the PCIe end-points, some of
them can be embedded into the DW PCIe Root Port/End-point controllers.
Seeing some abstract number in for instance IRQ handlers list doesn't give
a notion regarding their reference to the particular DMA controller.
Secondly current DW eDMA chip id implementation doesn't provide the
multi-eDMA platforms support for same reason of possibly having eDMA
detected on different system buses. At the same time re-implementing
something ida-based won't give much benefits especially seeing the DW eDMA
chip ID is only used in the IRQ request procedure. So to speak in order to
preserve the code simplicity and get to have the multi-eDMA platforms
support let's just use the parental device name to create the DW eDMA
controller name.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

---

Changelog v2:
- Slightly extend the eDMA name array. (@Manivannan)
---
 drivers/dma/dw-edma/dw-edma-core.c | 3 ++-
 drivers/dma/dw-edma/dw-edma-core.h | 2 +-
 drivers/dma/dw-edma/dw-edma-pcie.c | 1 -
 include/linux/dma/edma.h           | 1 -
 4 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 040a88cfe070..e3671bfbe186 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -973,7 +973,8 @@ int dw_edma_probe(struct dw_edma_chip *chip)
 	if (!dw->chan)
 		return -ENOMEM;
 
-	snprintf(dw->name, sizeof(dw->name), "dw-edma-core:%d", chip->id);
+	snprintf(dw->name, sizeof(dw->name), "dw-edma-core:%s",
+		 dev_name(chip->dev));
 
 	/* Disable eDMA, only to establish the ideal initial conditions */
 	dw_edma_v0_core_off(dw);
diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h
index e3ad3e372b55..0ab2b6dba880 100644
--- a/drivers/dma/dw-edma/dw-edma-core.h
+++ b/drivers/dma/dw-edma/dw-edma-core.h
@@ -96,7 +96,7 @@ struct dw_edma_irq {
 };
 
 struct dw_edma {
-	char				name[20];
+	char				name[32];
 
 	struct dma_device		dma;
 
diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
index f530bacfd716..3f9dadc73854 100644
--- a/drivers/dma/dw-edma/dw-edma-pcie.c
+++ b/drivers/dma/dw-edma/dw-edma-pcie.c
@@ -222,7 +222,6 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 
 	/* Data structure initialization */
 	chip->dev = dev;
-	chip->id = pdev->devfn;
 
 	chip->mf = vsec_data.mf;
 	chip->nr_irqs = nr_irqs;
diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
index 380a0a3e251f..9d44da4aa59d 100644
--- a/include/linux/dma/edma.h
+++ b/include/linux/dma/edma.h
@@ -76,7 +76,6 @@ enum dw_edma_chip_flags {
  */
 struct dw_edma_chip {
 	struct device		*dev;
-	int			id;
 	int			nr_irqs;
 	const struct dw_edma_core_ops   *ops;
 	u32			flags;
-- 
2.38.0

[PATCH v6 22/24] dmaengine: dw-edma: Bypass dma-ranges mapping for the local setup

[Serge Semin]

DW eDMA doesn't perform any translation of the traffic generated on the
CPU/Application side. It just generates read/write AXI-bus requests with
the specified addresses. But in case if the dma-ranges DT-property is
specified for a platform device node, Linux will use it to create a
mapping the PCIe-bus regions into the CPU memory ranges. This isn't what
we want for the eDMA embedded into the locally accessed DW PCIe Root Port
and End-point. In order to work that around let's set the chan_dma_dev
flag for each DW eDMA channel thus forcing the client drivers to getting a
custom dma-ranges-less parental device for the mappings.

Note it will only work for the client drivers using the
dmaengine_get_dma_device() method to get the parental DMA device.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>

---

Changelog v2:
- Fix the comment a bit to being clearer. (@Manivannan)

Changelog v3:
- Conditionally set dchan->dev->device.dma_coherent field since it can
  be missing on some platforms. (@Manivannan)
- Remove Manivannan' rb and tb tags since the patch content has been
  changed.

Changelog v6:
- Directly call *_dma_configure() method on the child device used for
  the DMA buffers mapping. (@Robin)
- Explicitly set the DMA-mask of the child device in the channel
  allocation proecedure. (@Robin)
- Drop @Manivannan and @Vinod rb- and ab-tags due to significant patch
  content change.
---
 drivers/dma/dw-edma/dw-edma-core.c | 44 ++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index e3671bfbe186..846518509753 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -6,9 +6,11 @@
  * Author: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
  */
 
+#include <linux/acpi.h>
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
+#include <linux/of_device.h>
 #include <linux/dmaengine.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
@@ -711,10 +713,52 @@ static irqreturn_t dw_edma_interrupt_common(int irq, void *data)
 static int dw_edma_alloc_chan_resources(struct dma_chan *dchan)
 {
 	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
+	struct device *dev = chan->dw->chip->dev;
+	int ret;
 
 	if (chan->status != EDMA_ST_IDLE)
 		return -EBUSY;
 
+	/* Bypass the dma-ranges based memory regions mapping for the eDMA
+	 * controlled from the CPU/Application side since in that case
+	 * the local memory address is left untranslated.
+	 */
+	if (chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) {
+		ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
+						   DMA_BIT_MASK(64));
+		if (ret) {
+			ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
+							   DMA_BIT_MASK(32));
+			if (ret)
+				return ret;
+		}
+
+		if (dev_of_node(dev)) {
+			struct device_node *node = dev_of_node(dev);
+
+			ret = of_dma_configure(&dchan->dev->device, node, true);
+		} else if (has_acpi_companion(dev)) {
+			struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
+
+			ret = acpi_dma_configure(&dchan->dev->device,
+						 acpi_get_dma_attr(adev));
+		} else {
+			ret = -EINVAL;
+		}
+
+		if (ret)
+			return ret;
+
+		if (dchan->dev->device.dma_range_map) {
+			kfree(dchan->dev->device.dma_range_map);
+			dchan->dev->device.dma_range_map = NULL;
+		}
+
+		dchan->dev->chan_dma_dev = true;
+	} else {
+		dchan->dev->chan_dma_dev = false;
+	}
+
 	return 0;
 }
 
-- 
2.38.0

[PATCH v6 23/24] dmaengine: dw-edma: Skip cleanup procedure if no private data found

[Serge Semin]

DW eDMA driver private data is preserved in the passed DW eDMA chip info
structure. If either probe procedure failed or for some reason the passed
info object doesn't have private data pointer initialized we need to halt
the DMA device cleanup procedure in order to prevent possible system
crashes.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
---
 drivers/dma/dw-edma/dw-edma-core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 846518509753..a1cb022a03f4 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -1055,6 +1055,10 @@ int dw_edma_remove(struct dw_edma_chip *chip)
 	struct dw_edma *dw = chip->dw;
 	int i;
 
+	/* Skip removal if no private data found */
+	if (!dw)
+		return -ENODEV;
+
 	/* Disable eDMA */
 	dw_edma_v0_core_off(dw);
 
-- 
2.38.0

[PATCH v6 24/24] PCI: dwc: Add DW eDMA engine support

[Serge Semin]

Since the DW eDMA driver now supports eDMA controllers embedded into the
locally accessible DW PCIe Root Ports and Endpoints, we can use the
updated interface to register DW eDMA as DMA engine device if it's
available. In order to successfully do that the DW PCIe core driver need
to perform some preparations first. First of all it needs to find out the
eDMA controller CSRs base address, whether they are accessible over the
Port Logic or iATU unrolled space. Afterwards it can try to auto-detect
the eDMA controller availability and number of read/write channels.
If none was found the procedure will just silently halt with no error
returned. Secondly the platform is supposed to provide either combined or
per-channel IRQ signals. If no valid IRQs set is found the procedure will
also halt with no error returned so to be backward compatible with the
platforms where DW PCIe controllers have eDMA embedded but lack of the
IRQs defined for them. Finally before actually probing the eDMA device we
need to allocate LLP items buffers. After that the DW eDMA can be
registered. If registration is successful the info-message regarding the
number of detected Read/Write eDMA channels will be printed to the system
as is done for the iATU settings.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

---

Changelog v2:
- Don't fail eDMA detection procedure if the DW eDMA driver couldn't probe
  device. That happens if the driver is disabled. (@Manivannan)
- Add "dma" registers resource mapping procedure. (@Manivannan)
- Move the eDMA CSRs space detection into the dw_pcie_map_detect() method.
- Remove eDMA on the dw_pcie_ep_init() internal errors. (@Manivannan)
- Remove eDMA in the dw_pcie_ep_exit() method.
- Move the dw_pcie_edma_detect() method execution to the tail of the
  dw_pcie_ep_init() function.

Changelog v3:
- Add more comprehensive and less regression prune eDMA block detection
  procedure.
- Remove Manivannan tb tag since the patch content has been changed.

Changelog v6:
- Fix some patchlog and in-line comments misspells. (@Bjorn)
---
 .../pci/controller/dwc/pcie-designware-ep.c   |  12 +-
 .../pci/controller/dwc/pcie-designware-host.c |  13 +-
 drivers/pci/controller/dwc/pcie-designware.c  | 186 ++++++++++++++++++
 drivers/pci/controller/dwc/pcie-designware.h  |  20 ++
 4 files changed, 228 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 80a64b63c055..0fe83f08e0d6 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -612,8 +612,11 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
 
 void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
 {
+	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 	struct pci_epc *epc = ep->epc;
 
+	dw_pcie_edma_remove(pci);
+
 	pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
 			      epc->mem->window.page_size);
 
@@ -767,6 +770,10 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 		goto err_exit_epc_mem;
 	}
 
+	ret = dw_pcie_edma_detect(pci);
+	if (ret)
+		goto err_free_epc_mem;
+
 	if (ep->ops->get_features) {
 		epc_features = ep->ops->get_features(ep);
 		if (epc_features->core_init_notifier)
@@ -775,10 +782,13 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 
 	ret = dw_pcie_ep_init_complete(ep);
 	if (ret)
-		goto err_free_epc_mem;
+		goto err_remove_edma;
 
 	return 0;
 
+err_remove_edma:
+	dw_pcie_edma_remove(pci);
+
 err_free_epc_mem:
 	pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
 			      epc->mem->window.page_size);
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 3ab6ae3712c4..d18ff0519a62 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -467,14 +467,18 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
 
 	dw_pcie_iatu_detect(pci);
 
-	ret = dw_pcie_setup_rc(pp);
+	ret = dw_pcie_edma_detect(pci);
 	if (ret)
 		goto err_free_msi;
 
+	ret = dw_pcie_setup_rc(pp);
+	if (ret)
+		goto err_remove_edma;
+
 	if (!dw_pcie_link_up(pci)) {
 		ret = dw_pcie_start_link(pci);
 		if (ret)
-			goto err_free_msi;
+			goto err_remove_edma;
 	}
 
 	/* Ignore errors, the link may come up later */
@@ -491,6 +495,9 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
 err_stop_link:
 	dw_pcie_stop_link(pci);
 
+err_remove_edma:
+	dw_pcie_edma_remove(pci);
+
 err_free_msi:
 	if (pp->has_msi_ctrl)
 		dw_pcie_free_msi(pp);
@@ -512,6 +519,8 @@ void dw_pcie_host_deinit(struct dw_pcie_rp *pp)
 
 	dw_pcie_stop_link(pci);
 
+	dw_pcie_edma_remove(pci);
+
 	if (pp->has_msi_ctrl)
 		dw_pcie_free_msi(pp);
 
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 1e06ccf2dc9e..3dcbdaf980e4 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -12,6 +12,7 @@
 #include <linux/bitops.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/dma/edma.h>
 #include <linux/gpio/consumer.h>
 #include <linux/ioport.h>
 #include <linux/of.h>
@@ -142,6 +143,18 @@ int dw_pcie_get_resources(struct dw_pcie *pci)
 	if (!pci->atu_size)
 		pci->atu_size = SZ_4K;
 
+	/* eDMA region can be mapped to a custom base address */
+	if (!pci->edma.reg_base) {
+		res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dma");
+		if (res) {
+			pci->edma.reg_base = devm_ioremap_resource(pci->dev, res);
+			if (IS_ERR(pci->edma.reg_base))
+				return PTR_ERR(pci->edma.reg_base);
+		} else if (pci->atu_size >= 2 * DEFAULT_DBI_DMA_OFFSET) {
+			pci->edma.reg_base = pci->atu_base + DEFAULT_DBI_DMA_OFFSET;
+		}
+	}
+
 	/* LLDD is supposed to manually switch the clocks and resets state */
 	if (dw_pcie_cap_is(pci, REQ_RES)) {
 		ret = dw_pcie_get_clocks(pci);
@@ -782,6 +795,179 @@ void dw_pcie_iatu_detect(struct dw_pcie *pci)
 		 pci->region_align / SZ_1K, (pci->region_limit + 1) / SZ_1G);
 }
 
+static u32 dw_pcie_readl_dma(struct dw_pcie *pci, u32 reg)
+{
+	u32 val = 0;
+	int ret;
+
+	if (pci->ops && pci->ops->read_dbi)
+		return pci->ops->read_dbi(pci, pci->edma.reg_base, reg, 4);
+
+	ret = dw_pcie_read(pci->edma.reg_base + reg, 4, &val);
+	if (ret)
+		dev_err(pci->dev, "Read DMA address failed\n");
+
+	return val;
+}
+
+static int dw_pcie_edma_irq_vector(struct device *dev, unsigned int nr)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	char name[6];
+	int ret;
+
+	if (nr >= EDMA_MAX_WR_CH + EDMA_MAX_RD_CH)
+		return -EINVAL;
+
+	ret = platform_get_irq_byname_optional(pdev, "dma");
+	if (ret > 0)
+		return ret;
+
+	snprintf(name, sizeof(name), "dma%u", nr);
+
+	return platform_get_irq_byname_optional(pdev, name);
+}
+
+static struct dw_edma_core_ops dw_pcie_edma_ops = {
+	.irq_vector = dw_pcie_edma_irq_vector,
+};
+
+static int dw_pcie_edma_find_chip(struct dw_pcie *pci)
+{
+	u32 val;
+
+	val = dw_pcie_readl_dbi(pci, PCIE_DMA_VIEWPORT_BASE + PCIE_DMA_CTRL);
+	if (val == 0xFFFFFFFF && pci->edma.reg_base) {
+		pci->edma.mf = EDMA_MF_EDMA_UNROLL;
+
+		val = dw_pcie_readl_dma(pci, PCIE_DMA_CTRL);
+	} else if (val != 0xFFFFFFFF) {
+		pci->edma.mf = EDMA_MF_EDMA_LEGACY;
+
+		pci->edma.reg_base = pci->dbi_base + PCIE_DMA_VIEWPORT_BASE;
+	} else {
+		return -ENODEV;
+	}
+
+	pci->edma.dev = pci->dev;
+
+	if (!pci->edma.ops)
+		pci->edma.ops = &dw_pcie_edma_ops;
+
+	pci->edma.flags |= DW_EDMA_CHIP_LOCAL;
+
+	pci->edma.ll_wr_cnt = FIELD_GET(PCIE_DMA_NUM_WR_CHAN, val);
+	pci->edma.ll_rd_cnt = FIELD_GET(PCIE_DMA_NUM_RD_CHAN, val);
+
+	/* Sanity check the channels count if the mapping was incorrect */
+	if (!pci->edma.ll_wr_cnt || pci->edma.ll_wr_cnt > EDMA_MAX_WR_CH ||
+	    !pci->edma.ll_rd_cnt || pci->edma.ll_rd_cnt > EDMA_MAX_RD_CH)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int dw_pcie_edma_irq_verify(struct dw_pcie *pci)
+{
+	struct platform_device *pdev = to_platform_device(pci->dev);
+	u16 ch_cnt = pci->edma.ll_wr_cnt + pci->edma.ll_rd_cnt;
+	char name[6];
+	int ret;
+
+	if (pci->edma.nr_irqs == 1)
+		return 0;
+	else if (pci->edma.nr_irqs > 1)
+		return pci->edma.nr_irqs != ch_cnt ? -EINVAL : 0;
+
+	ret = platform_get_irq_byname_optional(pdev, "dma");
+	if (ret > 0) {
+		pci->edma.nr_irqs = 1;
+		return 0;
+	}
+
+	for (; pci->edma.nr_irqs < ch_cnt; pci->edma.nr_irqs++) {
+		snprintf(name, sizeof(name), "dma%d", pci->edma.nr_irqs);
+
+		ret = platform_get_irq_byname_optional(pdev, name);
+		if (ret <= 0)
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int dw_pcie_edma_ll_alloc(struct dw_pcie *pci)
+{
+	struct dw_edma_region *ll;
+	dma_addr_t paddr;
+	int i;
+
+	for (i = 0; i < pci->edma.ll_wr_cnt; i++) {
+		ll = &pci->edma.ll_region_wr[i];
+		ll->sz = DMA_LLP_MEM_SIZE;
+		ll->vaddr = dmam_alloc_coherent(pci->dev, ll->sz,
+						&paddr, GFP_KERNEL);
+		if (!ll->vaddr)
+			return -ENOMEM;
+
+		ll->paddr = paddr;
+	}
+
+	for (i = 0; i < pci->edma.ll_rd_cnt; i++) {
+		ll = &pci->edma.ll_region_rd[i];
+		ll->sz = DMA_LLP_MEM_SIZE;
+		ll->vaddr = dmam_alloc_coherent(pci->dev, ll->sz,
+						&paddr, GFP_KERNEL);
+		if (!ll->vaddr)
+			return -ENOMEM;
+
+		ll->paddr = paddr;
+	}
+
+	return 0;
+}
+
+int dw_pcie_edma_detect(struct dw_pcie *pci)
+{
+	int ret;
+
+	/* Don't fail if no eDMA was found (for the backward compatibility) */
+	ret = dw_pcie_edma_find_chip(pci);
+	if (ret)
+		return 0;
+
+	/* Don't fail on the IRQs verification (for the backward compatibility) */
+	ret = dw_pcie_edma_irq_verify(pci);
+	if (ret) {
+		dev_err(pci->dev, "Invalid eDMA IRQs found\n");
+		return 0;
+	}
+
+	ret = dw_pcie_edma_ll_alloc(pci);
+	if (ret) {
+		dev_err(pci->dev, "Couldn't allocate LLP memory\n");
+		return ret;
+	}
+
+	/* Don't fail if the DW eDMA driver can't find the device */
+	ret = dw_edma_probe(&pci->edma);
+	if (ret && ret != -ENODEV) {
+		dev_err(pci->dev, "Couldn't register eDMA device\n");
+		return ret;
+	}
+
+	dev_info(pci->dev, "eDMA: unroll %s, %hu wr, %hu rd\n",
+		 pci->edma.mf == EDMA_MF_EDMA_UNROLL ? "T" : "F",
+		 pci->edma.ll_wr_cnt, pci->edma.ll_rd_cnt);
+
+	return 0;
+}
+
+void dw_pcie_edma_remove(struct dw_pcie *pci)
+{
+	dw_edma_remove(&pci->edma);
+}
+
 void dw_pcie_setup(struct dw_pcie *pci)
 {
 	u32 val;
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 393dfb931df6..028155c03acd 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -15,6 +15,7 @@
 #include <linux/bitops.h>
 #include <linux/clk.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma/edma.h>
 #include <linux/gpio/consumer.h>
 #include <linux/irq.h>
 #include <linux/msi.h>
@@ -167,6 +168,18 @@
 #define PCIE_MSIX_DOORBELL		0x948
 #define PCIE_MSIX_DOORBELL_PF_SHIFT	24
 
+/*
+ * eDMA CSRs. DW PCIe IP-core v4.70a and older had the eDMA registers accessible
+ * over the Port Logic registers space. Afterwards the unrolled mapping was
+ * introduced so eDMA and iATU could be accessed via a dedicated registers
+ * space.
+ */
+#define PCIE_DMA_VIEWPORT_BASE		0x970
+#define PCIE_DMA_UNROLL_BASE		0x80000
+#define PCIE_DMA_CTRL			0x008
+#define PCIE_DMA_NUM_WR_CHAN		GENMASK(3, 0)
+#define PCIE_DMA_NUM_RD_CHAN		GENMASK(19, 16)
+
 #define PCIE_PL_CHK_REG_CONTROL_STATUS			0xB20
 #define PCIE_PL_CHK_REG_CHK_REG_START			BIT(0)
 #define PCIE_PL_CHK_REG_CHK_REG_CONTINUOUS		BIT(1)
@@ -215,6 +228,7 @@
  * this offset, if atu_base not set.
  */
 #define DEFAULT_DBI_ATU_OFFSET (0x3 << 20)
+#define DEFAULT_DBI_DMA_OFFSET PCIE_DMA_UNROLL_BASE
 
 #define MAX_MSI_IRQS			256
 #define MAX_MSI_IRQS_PER_CTRL		32
@@ -226,6 +240,9 @@
 #define MAX_IATU_IN			256
 #define MAX_IATU_OUT			256
 
+/* Default eDMA LLP memory size */
+#define DMA_LLP_MEM_SIZE		PAGE_SIZE
+
 struct dw_pcie;
 struct dw_pcie_rp;
 struct dw_pcie_ep;
@@ -369,6 +386,7 @@ struct dw_pcie {
 	int			num_lanes;
 	int			link_gen;
 	u8			n_fts[2];
+	struct dw_edma_chip	edma;
 	struct clk_bulk_data	app_clks[DW_PCIE_NUM_APP_CLKS];
 	struct clk_bulk_data	core_clks[DW_PCIE_NUM_CORE_CLKS];
 	struct reset_control_bulk_data	app_rsts[DW_PCIE_NUM_APP_RSTS];
@@ -408,6 +426,8 @@ int dw_pcie_prog_ep_inbound_atu(struct dw_pcie *pci, u8 func_no, int index,
 void dw_pcie_disable_atu(struct dw_pcie *pci, u32 dir, int index);
 void dw_pcie_setup(struct dw_pcie *pci);
 void dw_pcie_iatu_detect(struct dw_pcie *pci);
+int dw_pcie_edma_detect(struct dw_pcie *pci);
+void dw_pcie_edma_remove(struct dw_pcie *pci);
 
 static inline void dw_pcie_writel_dbi(struct dw_pcie *pci, u32 reg, u32 val)
 {
-- 
2.38.0

Re: [PATCH v6 22/24] dmaengine: dw-edma: Bypass dma-ranges mapping for the local setup

[Serge Semin]

On Tue, Nov 08, 2022 at 12:04:36AM +0300, Serge Semin wrote:
> DW eDMA doesn't perform any translation of the traffic generated on the
> CPU/Application side. It just generates read/write AXI-bus requests with
> the specified addresses. But in case if the dma-ranges DT-property is
> specified for a platform device node, Linux will use it to create a
> mapping the PCIe-bus regions into the CPU memory ranges. This isn't what
> we want for the eDMA embedded into the locally accessed DW PCIe Root Port
> and End-point. In order to work that around let's set the chan_dma_dev
> flag for each DW eDMA channel thus forcing the client drivers to getting a
> custom dma-ranges-less parental device for the mappings.
> 
> Note it will only work for the client drivers using the
> dmaengine_get_dma_device() method to get the parental DMA device.

@Robin, we particularly need you opinion on this patch. I did as you
said: call *_dma_configure() method to initialize the child device and
set the DMA-mask here instead of the platform driver.

@Vinoud, @Manivannan I had to drop your tags from this patch since its
content had been significantly changed.

-Sergey

> 
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> 
> ---
> 
> Changelog v2:
> - Fix the comment a bit to being clearer. (@Manivannan)
> 
> Changelog v3:
> - Conditionally set dchan->dev->device.dma_coherent field since it can
>   be missing on some platforms. (@Manivannan)
> - Remove Manivannan' rb and tb tags since the patch content has been
>   changed.
> 
> Changelog v6:
> - Directly call *_dma_configure() method on the child device used for
>   the DMA buffers mapping. (@Robin)
> - Explicitly set the DMA-mask of the child device in the channel
>   allocation proecedure. (@Robin)
> - Drop @Manivannan and @Vinod rb- and ab-tags due to significant patch
>   content change.
> ---
>  drivers/dma/dw-edma/dw-edma-core.c | 44 ++++++++++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
> 
> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> index e3671bfbe186..846518509753 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-core.c
> @@ -6,9 +6,11 @@
>   * Author: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
>   */
>  
> +#include <linux/acpi.h>
>  #include <linux/module.h>
>  #include <linux/device.h>
>  #include <linux/kernel.h>
> +#include <linux/of_device.h>
>  #include <linux/dmaengine.h>
>  #include <linux/err.h>
>  #include <linux/interrupt.h>
> @@ -711,10 +713,52 @@ static irqreturn_t dw_edma_interrupt_common(int irq, void *data)
>  static int dw_edma_alloc_chan_resources(struct dma_chan *dchan)
>  {
>  	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> +	struct device *dev = chan->dw->chip->dev;
> +	int ret;
>  
>  	if (chan->status != EDMA_ST_IDLE)
>  		return -EBUSY;
>  
> +	/* Bypass the dma-ranges based memory regions mapping for the eDMA
> +	 * controlled from the CPU/Application side since in that case
> +	 * the local memory address is left untranslated.
> +	 */
> +	if (chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) {
> +		ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
> +						   DMA_BIT_MASK(64));
> +		if (ret) {
> +			ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
> +							   DMA_BIT_MASK(32));
> +			if (ret)
> +				return ret;
> +		}
> +
> +		if (dev_of_node(dev)) {
> +			struct device_node *node = dev_of_node(dev);
> +
> +			ret = of_dma_configure(&dchan->dev->device, node, true);
> +		} else if (has_acpi_companion(dev)) {
> +			struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
> +
> +			ret = acpi_dma_configure(&dchan->dev->device,
> +						 acpi_get_dma_attr(adev));
> +		} else {
> +			ret = -EINVAL;
> +		}
> +
> +		if (ret)
> +			return ret;
> +
> +		if (dchan->dev->device.dma_range_map) {
> +			kfree(dchan->dev->device.dma_range_map);
> +			dchan->dev->device.dma_range_map = NULL;
> +		}
> +
> +		dchan->dev->chan_dma_dev = true;
> +	} else {
> +		dchan->dev->chan_dma_dev = false;
> +	}
> +
>  	return 0;
>  }
>  
> -- 
> 2.38.0
> 
> 

Re: [PATCH v6 22/24] dmaengine: dw-edma: Bypass dma-ranges mapping for the local setup

[Robin Murphy]

On 2022-11-07 21:11, Serge Semin wrote:
> On Tue, Nov 08, 2022 at 12:04:36AM +0300, Serge Semin wrote:
>> DW eDMA doesn't perform any translation of the traffic generated on the
>> CPU/Application side. It just generates read/write AXI-bus requests with
>> the specified addresses. But in case if the dma-ranges DT-property is
>> specified for a platform device node, Linux will use it to create a
>> mapping the PCIe-bus regions into the CPU memory ranges. This isn't what
>> we want for the eDMA embedded into the locally accessed DW PCIe Root Port
>> and End-point. In order to work that around let's set the chan_dma_dev
>> flag for each DW eDMA channel thus forcing the client drivers to getting a
>> custom dma-ranges-less parental device for the mappings.
>>
>> Note it will only work for the client drivers using the
>> dmaengine_get_dma_device() method to get the parental DMA device.
> 
> @Robin, we particularly need you opinion on this patch. I did as you
> said: call *_dma_configure() method to initialize the child device and
> set the DMA-mask here instead of the platform driver.

Apologies, I've been busy and this series got buried in my inbox before 
I'd clocked it as something I was supposed to be looking at.

> @Vinoud, @Manivannan I had to drop your tags from this patch since its
> content had been significantly changed.
> 
> -Sergey
> 
>>
>> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
>>
>> ---
>>
>> Changelog v2:
>> - Fix the comment a bit to being clearer. (@Manivannan)
>>
>> Changelog v3:
>> - Conditionally set dchan->dev->device.dma_coherent field since it can
>>    be missing on some platforms. (@Manivannan)
>> - Remove Manivannan' rb and tb tags since the patch content has been
>>    changed.
>>
>> Changelog v6:
>> - Directly call *_dma_configure() method on the child device used for
>>    the DMA buffers mapping. (@Robin)
>> - Explicitly set the DMA-mask of the child device in the channel
>>    allocation proecedure. (@Robin)
>> - Drop @Manivannan and @Vinod rb- and ab-tags due to significant patch
>>    content change.
>> ---
>>   drivers/dma/dw-edma/dw-edma-core.c | 44 ++++++++++++++++++++++++++++++
>>   1 file changed, 44 insertions(+)
>>
>> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
>> index e3671bfbe186..846518509753 100644
>> --- a/drivers/dma/dw-edma/dw-edma-core.c
>> +++ b/drivers/dma/dw-edma/dw-edma-core.c
>> @@ -6,9 +6,11 @@
>>    * Author: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
>>    */
>>   
>> +#include <linux/acpi.h>
>>   #include <linux/module.h>
>>   #include <linux/device.h>
>>   #include <linux/kernel.h>
>> +#include <linux/of_device.h>
>>   #include <linux/dmaengine.h>
>>   #include <linux/err.h>
>>   #include <linux/interrupt.h>
>> @@ -711,10 +713,52 @@ static irqreturn_t dw_edma_interrupt_common(int irq, void *data)
>>   static int dw_edma_alloc_chan_resources(struct dma_chan *dchan)
>>   {
>>   	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
>> +	struct device *dev = chan->dw->chip->dev;
>> +	int ret;
>>   
>>   	if (chan->status != EDMA_ST_IDLE)
>>   		return -EBUSY;
>>   
>> +	/* Bypass the dma-ranges based memory regions mapping for the eDMA
>> +	 * controlled from the CPU/Application side since in that case
>> +	 * the local memory address is left untranslated.
>> +	 */
>> +	if (chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) {
>> +		ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
>> +						   DMA_BIT_MASK(64));
>> +		if (ret) {

Setting a 64-bit mask should never fail, especially on any platform that 
will actually run this code.

>> +			ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
>> +							   DMA_BIT_MASK(32));
>> +			if (ret)
>> +				return ret;
>> +		}
>> +
>> +		if (dev_of_node(dev)) {
>> +			struct device_node *node = dev_of_node(dev);
>> +
>> +			ret = of_dma_configure(&dchan->dev->device, node, true);
>> +		} else if (has_acpi_companion(dev)) {

Can this can ever happen? AFAICS there's no ACPI binding to match and 
probe the DWC driver, at best it could only probe as a standard PNP0A08 
host bridge which wouldn't know anything about eDMA anyway.

>> +			struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
>> +
>> +			ret = acpi_dma_configure(&dchan->dev->device,
>> +						 acpi_get_dma_attr(adev));
>> +		} else {
>> +			ret = -EINVAL;
>> +		}
>> +
>> +		if (ret)
>> +			return ret;
>> +
>> +		if (dchan->dev->device.dma_range_map) {
>> +			kfree(dchan->dev->device.dma_range_map);
>> +			dchan->dev->device.dma_range_map = NULL;
>> +		}

Ugh, I guess this is still here because now you're passing the channel 
device to of_dma_configure() such that it looks like a PCI child :(

Can we just set "chan->dev->device.of_node = dev->of_node;" beforehand 
so it works as expected (with f1ad5338a4d5 in place) and we don't need 
to be messing with the dma_range_map details at all? Note that that 
isn't as hacky as it might sound - it's a relatively well-established 
practice in places like I2C and SPI, and in this case it seems perfectly 
appropriate semantically as well.

(And there should be no need to bother with of_node refcounting, since 
the lifetime of the eDMA driver is bounded by the lifetime of the PCIe 
driver, thus the lifetime of the DMA channel devices is bounded by the 
lifetime of the PCIe platform device, which already holds a reference 
from of_device_alloc().)

Thanks,
Robin.

>> +
>> +		dchan->dev->chan_dma_dev = true;
>> +	} else {
>> +		dchan->dev->chan_dma_dev = false;
>> +	}
>> +
>>   	return 0;
>>   }
>>   
>> -- 
>> 2.38.0
>>
>>

Re: [PATCH v6 22/24] dmaengine: dw-edma: Bypass dma-ranges mapping for the local setup

[Serge Semin]

On Fri, Nov 25, 2022 at 03:32:23PM +0000, Robin Murphy wrote:
> On 2022-11-07 21:11, Serge Semin wrote:
> > On Tue, Nov 08, 2022 at 12:04:36AM +0300, Serge Semin wrote:
> > > DW eDMA doesn't perform any translation of the traffic generated on the
> > > CPU/Application side. It just generates read/write AXI-bus requests with
> > > the specified addresses. But in case if the dma-ranges DT-property is
> > > specified for a platform device node, Linux will use it to create a
> > > mapping the PCIe-bus regions into the CPU memory ranges. This isn't what
> > > we want for the eDMA embedded into the locally accessed DW PCIe Root Port
> > > and End-point. In order to work that around let's set the chan_dma_dev
> > > flag for each DW eDMA channel thus forcing the client drivers to getting a
> > > custom dma-ranges-less parental device for the mappings.
> > > 
> > > Note it will only work for the client drivers using the
> > > dmaengine_get_dma_device() method to get the parental DMA device.
> > 
> > @Robin, we particularly need you opinion on this patch. I did as you
> > said: call *_dma_configure() method to initialize the child device and
> > set the DMA-mask here instead of the platform driver.
> 

> Apologies, I've been busy and this series got buried in my inbox before I'd
> clocked it as something I was supposed to be looking at.

No worries. I'm glad you responded.

> 
> > @Vinoud, @Manivannan I had to drop your tags from this patch since its
> > content had been significantly changed.
> > 
> > -Sergey
> > 
> > > 
> > > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> > > 
> > > ---
> > > 
> > > Changelog v2:
> > > - Fix the comment a bit to being clearer. (@Manivannan)
> > > 
> > > Changelog v3:
> > > - Conditionally set dchan->dev->device.dma_coherent field since it can
> > >    be missing on some platforms. (@Manivannan)
> > > - Remove Manivannan' rb and tb tags since the patch content has been
> > >    changed.
> > > 
> > > Changelog v6:
> > > - Directly call *_dma_configure() method on the child device used for
> > >    the DMA buffers mapping. (@Robin)
> > > - Explicitly set the DMA-mask of the child device in the channel
> > >    allocation proecedure. (@Robin)
> > > - Drop @Manivannan and @Vinod rb- and ab-tags due to significant patch
> > >    content change.
> > > ---
> > >   drivers/dma/dw-edma/dw-edma-core.c | 44 ++++++++++++++++++++++++++++++
> > >   1 file changed, 44 insertions(+)
> > > 
> > > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> > > index e3671bfbe186..846518509753 100644
> > > --- a/drivers/dma/dw-edma/dw-edma-core.c
> > > +++ b/drivers/dma/dw-edma/dw-edma-core.c
> > > @@ -6,9 +6,11 @@
> > >    * Author: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
> > >    */
> > > +#include <linux/acpi.h>
> > >   #include <linux/module.h>
> > >   #include <linux/device.h>
> > >   #include <linux/kernel.h>
> > > +#include <linux/of_device.h>
> > >   #include <linux/dmaengine.h>
> > >   #include <linux/err.h>
> > >   #include <linux/interrupt.h>
> > > @@ -711,10 +713,52 @@ static irqreturn_t dw_edma_interrupt_common(int irq, void *data)
> > >   static int dw_edma_alloc_chan_resources(struct dma_chan *dchan)
> > >   {
> > >   	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> > > +	struct device *dev = chan->dw->chip->dev;
> > > +	int ret;
> > >   	if (chan->status != EDMA_ST_IDLE)
> > >   		return -EBUSY;
> > > +	/* Bypass the dma-ranges based memory regions mapping for the eDMA
> > > +	 * controlled from the CPU/Application side since in that case
> > > +	 * the local memory address is left untranslated.
> > > +	 */
> > > +	if (chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) {


> > > +		ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
> > > +						   DMA_BIT_MASK(64));
> > > +		if (ret) {
> 
> Setting a 64-bit mask should never fail, especially on any platform that
> will actually run this code.
> 
> > > +			ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
> > > +							   DMA_BIT_MASK(32));

Indeed. I can just drop the 32-bit mask test then. (But I'd retain the
error check anyway.)

The problem is that actual device DMA-addressing capability is
determined by the MASTER_BUS_ADDR_WIDTH IP-core synthesize parameter.
I can't predict its value from this generic code since it isn't
auto-detectable and is platform-specific. That's why back then in
our discussion I was insisting on setting the mask in the low-level
device drivers. But after the commit 423511ec23e2 ("PCI: dwc: Drop
dependency on ZONE_DMA32") it turned to be pointless now since the
DMA-mask would be overwritten by the generic DW PCIe driver code anyway.
What do you suggest then in this regard? Just keep setting the 64-bit
mask only? This will work for my platform, but will fail for the
devices with AXI-bus address of only 32-bits width.

> > > +			if (ret)
> > > +				return ret;
> > > +		}
> > > +
> > > +		if (dev_of_node(dev)) {
> > > +			struct device_node *node = dev_of_node(dev);
> > > +
> > > +			ret = of_dma_configure(&dchan->dev->device, node, true);
> > > +		} else if (has_acpi_companion(dev)) {
> 

> Can this can ever happen? AFAICS there's no ACPI binding to match and probe
> the DWC driver, at best it could only probe as a standard PNP0A08 host
> bridge which wouldn't know anything about eDMA anyway.

There are several ACPI-based platforms with DW PCIe controllers:
pcie-tegra194-acpi.c, pcie-al.c, pcie-hisi.c. All of them are fully
ECAM-based so no DW eDMA probing from the Linux kernel implied. But
these are still DW PCIe controllers and they or some other ones can
have eDMA embedded. Do you think it won't be ever possible to either
directly handle these controllers (bypassing the ECAM interface) or
have a DW PCIe device accessed via the ACPI bindings?

Note basically what I've implemented here was based on the
platform_dma_configure() DMA-configuration code pattern. I thought it
was a reasonable choice since this code path is executed for the
platform devices only (implied by the DW_EDMA_CHIP_LOCAL flag
semantic).

On the second thought if the problem in subject is only specific to
the DT-based platforms, then I could just skip channel device
initialization here for the platform devices with no OF-node detected.
So the question is is it specific to the DT-based platforms only?

(Before answering to the question above please read the last comment
in this message.)

> 
> > > +			struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
> > > +
> > > +			ret = acpi_dma_configure(&dchan->dev->device,
> > > +						 acpi_get_dma_attr(adev));
> > > +		} else {
> > > +			ret = -EINVAL;
> > > +		}
> > > +
> > > +		if (ret)
> > > +			return ret;
> > > +
> > > +		if (dchan->dev->device.dma_range_map) {
> > > +			kfree(dchan->dev->device.dma_range_map);
> > > +			dchan->dev->device.dma_range_map = NULL;
> > > +		}
> 

> Ugh, I guess this is still here because now you're passing the channel
> device to of_dma_configure() such that it looks like a PCI child :(

No. It's still here because I successfully missed your email in my
work inbox so I thought you didn't fix that dma-ranges peculiarity of
the PCIe-host nodes.(

> 
> Can we just set "chan->dev->device.of_node = dev->of_node;" beforehand so it
> works as expected (with f1ad5338a4d5 in place) and we don't need to be
> messing with the dma_range_map details at all? Note that that isn't as hacky
> as it might sound - it's a relatively well-established practice in places
> like I2C and SPI, and in this case it seems perfectly appropriate
> semantically as well.

Of course we can. But now, thanks to your commit f1ad5338a4d5 ("of:
Fix "dma-ranges" handling for bus controllers"), there is no point in
any dma-ranges hack here because the dma-ranges property is no longer
parsed for the PCIe-host platform device. I can and will just drop the
custom DMA-channel device initialization from the patch. The only
issue left to solve is about setting the DMA-mask. Please see my notes
above regarding that problem.

-Serge(y)

> 
> (And there should be no need to bother with of_node refcounting, since the
> lifetime of the eDMA driver is bounded by the lifetime of the PCIe driver,
> thus the lifetime of the DMA channel devices is bounded by the lifetime of
> the PCIe platform device, which already holds a reference from
> of_device_alloc().)
> 
> Thanks,
> Robin.
> 
> > > +
> > > +		dchan->dev->chan_dma_dev = true;
> > > +	} else {
> > > +		dchan->dev->chan_dma_dev = false;
> > > +	}
> > > +
> > >   	return 0;
> > >   }
> > > -- 
> > > 2.38.0
> > > 
> > > 

Re: [PATCH v6 22/24] dmaengine: dw-edma: Bypass dma-ranges mapping for the local setup

[Serge Semin]

Robin,
Could you give your comments regarding the DMA-mask issue described
below? It would be great to resubmit a fixed revision of the series
on this week in order to make it possible to merge it into the kernel
on the next merge window.

-Sergey

On Sun, Nov 27, 2022 at 02:45:13AM +0300, Serge Semin wrote:
> On Fri, Nov 25, 2022 at 03:32:23PM +0000, Robin Murphy wrote:
> > On 2022-11-07 21:11, Serge Semin wrote:
> > > On Tue, Nov 08, 2022 at 12:04:36AM +0300, Serge Semin wrote:
> > > > DW eDMA doesn't perform any translation of the traffic generated on the
> > > > CPU/Application side. It just generates read/write AXI-bus requests with
> > > > the specified addresses. But in case if the dma-ranges DT-property is
> > > > specified for a platform device node, Linux will use it to create a
> > > > mapping the PCIe-bus regions into the CPU memory ranges. This isn't what
> > > > we want for the eDMA embedded into the locally accessed DW PCIe Root Port
> > > > and End-point. In order to work that around let's set the chan_dma_dev
> > > > flag for each DW eDMA channel thus forcing the client drivers to getting a
> > > > custom dma-ranges-less parental device for the mappings.
> > > > 
> > > > Note it will only work for the client drivers using the
> > > > dmaengine_get_dma_device() method to get the parental DMA device.
> > > 
> > > @Robin, we particularly need you opinion on this patch. I did as you
> > > said: call *_dma_configure() method to initialize the child device and
> > > set the DMA-mask here instead of the platform driver.
> > 
> 
> > Apologies, I've been busy and this series got buried in my inbox before I'd
> > clocked it as something I was supposed to be looking at.
> 
> No worries. I'm glad you responded.
> 
> > 
> > > @Vinoud, @Manivannan I had to drop your tags from this patch since its
> > > content had been significantly changed.
> > > 
> > > -Sergey
> > > 
> > > > 
> > > > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> > > > 
> > > > ---
> > > > 
> > > > Changelog v2:
> > > > - Fix the comment a bit to being clearer. (@Manivannan)
> > > > 
> > > > Changelog v3:
> > > > - Conditionally set dchan->dev->device.dma_coherent field since it can
> > > >    be missing on some platforms. (@Manivannan)
> > > > - Remove Manivannan' rb and tb tags since the patch content has been
> > > >    changed.
> > > > 
> > > > Changelog v6:
> > > > - Directly call *_dma_configure() method on the child device used for
> > > >    the DMA buffers mapping. (@Robin)
> > > > - Explicitly set the DMA-mask of the child device in the channel
> > > >    allocation proecedure. (@Robin)
> > > > - Drop @Manivannan and @Vinod rb- and ab-tags due to significant patch
> > > >    content change.
> > > > ---
> > > >   drivers/dma/dw-edma/dw-edma-core.c | 44 ++++++++++++++++++++++++++++++
> > > >   1 file changed, 44 insertions(+)
> > > > 
> > > > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> > > > index e3671bfbe186..846518509753 100644
> > > > --- a/drivers/dma/dw-edma/dw-edma-core.c
> > > > +++ b/drivers/dma/dw-edma/dw-edma-core.c
> > > > @@ -6,9 +6,11 @@
> > > >    * Author: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
> > > >    */
> > > > +#include <linux/acpi.h>
> > > >   #include <linux/module.h>
> > > >   #include <linux/device.h>
> > > >   #include <linux/kernel.h>
> > > > +#include <linux/of_device.h>
> > > >   #include <linux/dmaengine.h>
> > > >   #include <linux/err.h>
> > > >   #include <linux/interrupt.h>
> > > > @@ -711,10 +713,52 @@ static irqreturn_t dw_edma_interrupt_common(int irq, void *data)
> > > >   static int dw_edma_alloc_chan_resources(struct dma_chan *dchan)
> > > >   {
> > > >   	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> > > > +	struct device *dev = chan->dw->chip->dev;
> > > > +	int ret;
> > > >   	if (chan->status != EDMA_ST_IDLE)
> > > >   		return -EBUSY;
> > > > +	/* Bypass the dma-ranges based memory regions mapping for the eDMA
> > > > +	 * controlled from the CPU/Application side since in that case
> > > > +	 * the local memory address is left untranslated.
> > > > +	 */
> > > > +	if (chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) {
> 
> 
> > > > +		ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
> > > > +						   DMA_BIT_MASK(64));
> > > > +		if (ret) {
> > 
> > Setting a 64-bit mask should never fail, especially on any platform that
> > will actually run this code.
> > 
> > > > +			ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
> > > > +							   DMA_BIT_MASK(32));
> 
> Indeed. I can just drop the 32-bit mask test then. (But I'd retain the
> error check anyway.)
> 
> The problem is that actual device DMA-addressing capability is
> determined by the MASTER_BUS_ADDR_WIDTH IP-core synthesize parameter.
> I can't predict its value from this generic code since it isn't
> auto-detectable and is platform-specific. That's why back then in
> our discussion I was insisting on setting the mask in the low-level
> device drivers. But after the commit 423511ec23e2 ("PCI: dwc: Drop
> dependency on ZONE_DMA32") it turned to be pointless now since the
> DMA-mask would be overwritten by the generic DW PCIe driver code anyway.
> What do you suggest then in this regard? Just keep setting the 64-bit
> mask only? This will work for my platform, but will fail for the
> devices with AXI-bus address of only 32-bits width.
> 
> > > > +			if (ret)
> > > > +				return ret;
> > > > +		}
> > > > +
> > > > +		if (dev_of_node(dev)) {
> > > > +			struct device_node *node = dev_of_node(dev);
> > > > +
> > > > +			ret = of_dma_configure(&dchan->dev->device, node, true);
> > > > +		} else if (has_acpi_companion(dev)) {
> > 
> 
> > Can this can ever happen? AFAICS there's no ACPI binding to match and probe
> > the DWC driver, at best it could only probe as a standard PNP0A08 host
> > bridge which wouldn't know anything about eDMA anyway.
> 
> There are several ACPI-based platforms with DW PCIe controllers:
> pcie-tegra194-acpi.c, pcie-al.c, pcie-hisi.c. All of them are fully
> ECAM-based so no DW eDMA probing from the Linux kernel implied. But
> these are still DW PCIe controllers and they or some other ones can
> have eDMA embedded. Do you think it won't be ever possible to either
> directly handle these controllers (bypassing the ECAM interface) or
> have a DW PCIe device accessed via the ACPI bindings?
> 
> Note basically what I've implemented here was based on the
> platform_dma_configure() DMA-configuration code pattern. I thought it
> was a reasonable choice since this code path is executed for the
> platform devices only (implied by the DW_EDMA_CHIP_LOCAL flag
> semantic).
> 
> On the second thought if the problem in subject is only specific to
> the DT-based platforms, then I could just skip channel device
> initialization here for the platform devices with no OF-node detected.
> So the question is is it specific to the DT-based platforms only?
> 
> (Before answering to the question above please read the last comment
> in this message.)
> 
> > 
> > > > +			struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
> > > > +
> > > > +			ret = acpi_dma_configure(&dchan->dev->device,
> > > > +						 acpi_get_dma_attr(adev));
> > > > +		} else {
> > > > +			ret = -EINVAL;
> > > > +		}
> > > > +
> > > > +		if (ret)
> > > > +			return ret;
> > > > +
> > > > +		if (dchan->dev->device.dma_range_map) {
> > > > +			kfree(dchan->dev->device.dma_range_map);
> > > > +			dchan->dev->device.dma_range_map = NULL;
> > > > +		}
> > 
> 
> > Ugh, I guess this is still here because now you're passing the channel
> > device to of_dma_configure() such that it looks like a PCI child :(
> 
> No. It's still here because I successfully missed your email in my
> work inbox so I thought you didn't fix that dma-ranges peculiarity of
> the PCIe-host nodes.(
> 
> > 
> > Can we just set "chan->dev->device.of_node = dev->of_node;" beforehand so it
> > works as expected (with f1ad5338a4d5 in place) and we don't need to be
> > messing with the dma_range_map details at all? Note that that isn't as hacky
> > as it might sound - it's a relatively well-established practice in places
> > like I2C and SPI, and in this case it seems perfectly appropriate
> > semantically as well.
> 
> Of course we can. But now, thanks to your commit f1ad5338a4d5 ("of:
> Fix "dma-ranges" handling for bus controllers"), there is no point in
> any dma-ranges hack here because the dma-ranges property is no longer
> parsed for the PCIe-host platform device. I can and will just drop the
> custom DMA-channel device initialization from the patch. The only
> issue left to solve is about setting the DMA-mask. Please see my notes
> above regarding that problem.
> 
> -Serge(y)
> 
> > 
> > (And there should be no need to bother with of_node refcounting, since the
> > lifetime of the eDMA driver is bounded by the lifetime of the PCIe driver,
> > thus the lifetime of the DMA channel devices is bounded by the lifetime of
> > the PCIe platform device, which already holds a reference from
> > of_device_alloc().)
> > 
> > Thanks,
> > Robin.
> > 
> > > > +
> > > > +		dchan->dev->chan_dma_dev = true;
> > > > +	} else {
> > > > +		dchan->dev->chan_dma_dev = false;
> > > > +	}
> > > > +
> > > >   	return 0;
> > > >   }
> > > > -- 
> > > > 2.38.0
> > > > 
> > > > 

Re: [PATCH v6 22/24] dmaengine: dw-edma: Bypass dma-ranges mapping for the local setup

[Robin Murphy]

On 2022-11-26 23:45, Serge Semin wrote:
> On Fri, Nov 25, 2022 at 03:32:23PM +0000, Robin Murphy wrote:
>> On 2022-11-07 21:11, Serge Semin wrote:
>>> On Tue, Nov 08, 2022 at 12:04:36AM +0300, Serge Semin wrote:
>>>> DW eDMA doesn't perform any translation of the traffic generated on the
>>>> CPU/Application side. It just generates read/write AXI-bus requests with
>>>> the specified addresses. But in case if the dma-ranges DT-property is
>>>> specified for a platform device node, Linux will use it to create a
>>>> mapping the PCIe-bus regions into the CPU memory ranges. This isn't what
>>>> we want for the eDMA embedded into the locally accessed DW PCIe Root Port
>>>> and End-point. In order to work that around let's set the chan_dma_dev
>>>> flag for each DW eDMA channel thus forcing the client drivers to getting a
>>>> custom dma-ranges-less parental device for the mappings.
>>>>
>>>> Note it will only work for the client drivers using the
>>>> dmaengine_get_dma_device() method to get the parental DMA device.
>>>
>>> @Robin, we particularly need you opinion on this patch. I did as you
>>> said: call *_dma_configure() method to initialize the child device and
>>> set the DMA-mask here instead of the platform driver.
>>
> 
>> Apologies, I've been busy and this series got buried in my inbox before I'd
>> clocked it as something I was supposed to be looking at.
> 
> No worries. I'm glad you responded.
> 
>>
>>> @Vinoud, @Manivannan I had to drop your tags from this patch since its
>>> content had been significantly changed.
>>>
>>> -Sergey
>>>
>>>>
>>>> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
>>>>
>>>> ---
>>>>
>>>> Changelog v2:
>>>> - Fix the comment a bit to being clearer. (@Manivannan)
>>>>
>>>> Changelog v3:
>>>> - Conditionally set dchan->dev->device.dma_coherent field since it can
>>>>     be missing on some platforms. (@Manivannan)
>>>> - Remove Manivannan' rb and tb tags since the patch content has been
>>>>     changed.
>>>>
>>>> Changelog v6:
>>>> - Directly call *_dma_configure() method on the child device used for
>>>>     the DMA buffers mapping. (@Robin)
>>>> - Explicitly set the DMA-mask of the child device in the channel
>>>>     allocation proecedure. (@Robin)
>>>> - Drop @Manivannan and @Vinod rb- and ab-tags due to significant patch
>>>>     content change.
>>>> ---
>>>>    drivers/dma/dw-edma/dw-edma-core.c | 44 ++++++++++++++++++++++++++++++
>>>>    1 file changed, 44 insertions(+)
>>>>
>>>> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
>>>> index e3671bfbe186..846518509753 100644
>>>> --- a/drivers/dma/dw-edma/dw-edma-core.c
>>>> +++ b/drivers/dma/dw-edma/dw-edma-core.c
>>>> @@ -6,9 +6,11 @@
>>>>     * Author: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
>>>>     */
>>>> +#include <linux/acpi.h>
>>>>    #include <linux/module.h>
>>>>    #include <linux/device.h>
>>>>    #include <linux/kernel.h>
>>>> +#include <linux/of_device.h>
>>>>    #include <linux/dmaengine.h>
>>>>    #include <linux/err.h>
>>>>    #include <linux/interrupt.h>
>>>> @@ -711,10 +713,52 @@ static irqreturn_t dw_edma_interrupt_common(int irq, void *data)
>>>>    static int dw_edma_alloc_chan_resources(struct dma_chan *dchan)
>>>>    {
>>>>    	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
>>>> +	struct device *dev = chan->dw->chip->dev;
>>>> +	int ret;
>>>>    	if (chan->status != EDMA_ST_IDLE)
>>>>    		return -EBUSY;
>>>> +	/* Bypass the dma-ranges based memory regions mapping for the eDMA
>>>> +	 * controlled from the CPU/Application side since in that case
>>>> +	 * the local memory address is left untranslated.
>>>> +	 */
>>>> +	if (chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) {
> 
> 
>>>> +		ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
>>>> +						   DMA_BIT_MASK(64));
>>>> +		if (ret) {
>>
>> Setting a 64-bit mask should never fail, especially on any platform that
>> will actually run this code.
>>
>>>> +			ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
>>>> +							   DMA_BIT_MASK(32));
> 
> Indeed. I can just drop the 32-bit mask test then. (But I'd retain the
> error check anyway.)
> 
> The problem is that actual device DMA-addressing capability is
> determined by the MASTER_BUS_ADDR_WIDTH IP-core synthesize parameter.
> I can't predict its value from this generic code since it isn't
> auto-detectable and is platform-specific. That's why back then in
> our discussion I was insisting on setting the mask in the low-level
> device drivers. But after the commit 423511ec23e2 ("PCI: dwc: Drop
> dependency on ZONE_DMA32") it turned to be pointless now since the
> DMA-mask would be overwritten by the generic DW PCIe driver code anyway.
> What do you suggest then in this regard? Just keep setting the 64-bit
> mask only? This will work for my platform, but will fail for the
> devices with AXI-bus address of only 32-bits width.

OK, but you already have that problem either way. The point of 
dma_set_mask() et al is to inform the DMA API of your device's 
capability - setting a 64-bit mask is saying "I can use 64-bit addresses 
if you can" to the DMA layer, and as I say the DMA layer is almost 
always going to respond "indeed I can, let's do that". If the real DMA 
mask is platform-specific then you need to pass a platform-specific 
value here.

>>>> +			if (ret)
>>>> +				return ret;
>>>> +		}
>>>> +
>>>> +		if (dev_of_node(dev)) {
>>>> +			struct device_node *node = dev_of_node(dev);
>>>> +
>>>> +			ret = of_dma_configure(&dchan->dev->device, node, true);
>>>> +		} else if (has_acpi_companion(dev)) {
>>
> 
>> Can this can ever happen? AFAICS there's no ACPI binding to match and probe
>> the DWC driver, at best it could only probe as a standard PNP0A08 host
>> bridge which wouldn't know anything about eDMA anyway.
> 
> There are several ACPI-based platforms with DW PCIe controllers:
> pcie-tegra194-acpi.c, pcie-al.c, pcie-hisi.c. All of them are fully
> ECAM-based so no DW eDMA probing from the Linux kernel implied. But
> these are still DW PCIe controllers and they or some other ones can
> have eDMA embedded. Do you think it won't be ever possible to either
> directly handle these controllers (bypassing the ECAM interface) or
> have a DW PCIe device accessed via the ACPI bindings?

It's not entirely impossible, but would require new ACPI bindings and 
code changes to the dw-pci driver, so if somebody ever did do that work 
they should be responsible for any required changes at this end as well. 
There's no point adding untested dead code now, to maintain indefinitely 
just for the theoretical possibility that someone might ever make it 
reachable.

> Note basically what I've implemented here was based on the
> platform_dma_configure() DMA-configuration code pattern. I thought it
> was a reasonable choice since this code path is executed for the
> platform devices only (implied by the DW_EDMA_CHIP_LOCAL flag
> semantic).
> 
> On the second thought if the problem in subject is only specific to
> the DT-based platforms, then I could just skip channel device
> initialization here for the platform devices with no OF-node detected.
> So the question is is it specific to the DT-based platforms only?

I think you still want the DW_EDMA_CHIP_LOCAL flag, since the PCI 
endpoint device in the dw-edma-pcie case may have an of_node on some 
platforms, and in that case overriding the chan_dma_dev setup would be 
wrong. When the flag is set, though, we can simply assume dev_of_node() 
is valid since it's the only possible way for that to happen (and if 
someone does ever break that assumption in future, it will likely make 
itself noticed).

> (Before answering to the question above please read the last comment
> in this message.)
> 
>>
>>>> +			struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
>>>> +
>>>> +			ret = acpi_dma_configure(&dchan->dev->device,
>>>> +						 acpi_get_dma_attr(adev));
>>>> +		} else {
>>>> +			ret = -EINVAL;
>>>> +		}
>>>> +
>>>> +		if (ret)
>>>> +			return ret;
>>>> +
>>>> +		if (dchan->dev->device.dma_range_map) {
>>>> +			kfree(dchan->dev->device.dma_range_map);
>>>> +			dchan->dev->device.dma_range_map = NULL;
>>>> +		}
>>
> 
>> Ugh, I guess this is still here because now you're passing the channel
>> device to of_dma_configure() such that it looks like a PCI child :(
> 
> No. It's still here because I successfully missed your email in my
> work inbox so I thought you didn't fix that dma-ranges peculiarity of
> the PCIe-host nodes.(
> 
>>
>> Can we just set "chan->dev->device.of_node = dev->of_node;" beforehand so it
>> works as expected (with f1ad5338a4d5 in place) and we don't need to be
>> messing with the dma_range_map details at all? Note that that isn't as hacky
>> as it might sound - it's a relatively well-established practice in places
>> like I2C and SPI, and in this case it seems perfectly appropriate
>> semantically as well.
> 
> Of course we can. But now, thanks to your commit f1ad5338a4d5 ("of:
> Fix "dma-ranges" handling for bus controllers"), there is no point in
> any dma-ranges hack here because the dma-ranges property is no longer
> parsed for the PCIe-host platform device. I can and will just drop the
> custom DMA-channel device initialization from the patch. The only
> issue left to solve is about setting the DMA-mask. Please see my notes
> above regarding that problem.

Ah, I assumed you'd still want to keep the chan_dma_dev setup for the 
sake of independent DMA masks, at least until we get a better solution 
for the MSI stuff. If you're happy with the compromise of going back to 
using the real host device to keep things simple, that's fine by me.

Thanks,
Robin.

Re: [PATCH v6 22/24] dmaengine: dw-edma: Bypass dma-ranges mapping for the local setup

[Serge Semin]

On Thu, Dec 01, 2022 at 11:52:19AM +0000, Robin Murphy wrote:
> On 2022-11-26 23:45, Serge Semin wrote:
> > On Fri, Nov 25, 2022 at 03:32:23PM +0000, Robin Murphy wrote:
> > > On 2022-11-07 21:11, Serge Semin wrote:
> > > > On Tue, Nov 08, 2022 at 12:04:36AM +0300, Serge Semin wrote:
> > > > > DW eDMA doesn't perform any translation of the traffic generated on the
> > > > > CPU/Application side. It just generates read/write AXI-bus requests with
> > > > > the specified addresses. But in case if the dma-ranges DT-property is
> > > > > specified for a platform device node, Linux will use it to create a
> > > > > mapping the PCIe-bus regions into the CPU memory ranges. This isn't what
> > > > > we want for the eDMA embedded into the locally accessed DW PCIe Root Port
> > > > > and End-point. In order to work that around let's set the chan_dma_dev
> > > > > flag for each DW eDMA channel thus forcing the client drivers to getting a
> > > > > custom dma-ranges-less parental device for the mappings.
> > > > > 
> > > > > Note it will only work for the client drivers using the
> > > > > dmaengine_get_dma_device() method to get the parental DMA device.
> > > > 
> > > > @Robin, we particularly need you opinion on this patch. I did as you
> > > > said: call *_dma_configure() method to initialize the child device and
> > > > set the DMA-mask here instead of the platform driver.
> > > 
> > 
> > > Apologies, I've been busy and this series got buried in my inbox before I'd
> > > clocked it as something I was supposed to be looking at.
> > 
> > No worries. I'm glad you responded.
> > 
> > > 
> > > > @Vinoud, @Manivannan I had to drop your tags from this patch since its
> > > > content had been significantly changed.
> > > > 
> > > > -Sergey
> > > > 
> > > > > 
> > > > > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> > > > > 
> > > > > ---
> > > > > 
> > > > > Changelog v2:
> > > > > - Fix the comment a bit to being clearer. (@Manivannan)
> > > > > 
> > > > > Changelog v3:
> > > > > - Conditionally set dchan->dev->device.dma_coherent field since it can
> > > > >     be missing on some platforms. (@Manivannan)
> > > > > - Remove Manivannan' rb and tb tags since the patch content has been
> > > > >     changed.
> > > > > 
> > > > > Changelog v6:
> > > > > - Directly call *_dma_configure() method on the child device used for
> > > > >     the DMA buffers mapping. (@Robin)
> > > > > - Explicitly set the DMA-mask of the child device in the channel
> > > > >     allocation proecedure. (@Robin)
> > > > > - Drop @Manivannan and @Vinod rb- and ab-tags due to significant patch
> > > > >     content change.
> > > > > ---
> > > > >    drivers/dma/dw-edma/dw-edma-core.c | 44 ++++++++++++++++++++++++++++++
> > > > >    1 file changed, 44 insertions(+)
> > > > > 
> > > > > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> > > > > index e3671bfbe186..846518509753 100644
> > > > > --- a/drivers/dma/dw-edma/dw-edma-core.c
> > > > > +++ b/drivers/dma/dw-edma/dw-edma-core.c
> > > > > @@ -6,9 +6,11 @@
> > > > >     * Author: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
> > > > >     */
> > > > > +#include <linux/acpi.h>
> > > > >    #include <linux/module.h>
> > > > >    #include <linux/device.h>
> > > > >    #include <linux/kernel.h>
> > > > > +#include <linux/of_device.h>
> > > > >    #include <linux/dmaengine.h>
> > > > >    #include <linux/err.h>
> > > > >    #include <linux/interrupt.h>
> > > > > @@ -711,10 +713,52 @@ static irqreturn_t dw_edma_interrupt_common(int irq, void *data)
> > > > >    static int dw_edma_alloc_chan_resources(struct dma_chan *dchan)
> > > > >    {
> > > > >    	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> > > > > +	struct device *dev = chan->dw->chip->dev;
> > > > > +	int ret;
> > > > >    	if (chan->status != EDMA_ST_IDLE)
> > > > >    		return -EBUSY;
> > > > > +	/* Bypass the dma-ranges based memory regions mapping for the eDMA
> > > > > +	 * controlled from the CPU/Application side since in that case
> > > > > +	 * the local memory address is left untranslated.
> > > > > +	 */
> > > > > +	if (chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) {
> > 
> > 
> > > > > +		ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
> > > > > +						   DMA_BIT_MASK(64));
> > > > > +		if (ret) {
> > > 
> > > Setting a 64-bit mask should never fail, especially on any platform that
> > > will actually run this code.
> > > 
> > > > > +			ret = dma_coerce_mask_and_coherent(&dchan->dev->device,
> > > > > +							   DMA_BIT_MASK(32));
> > 
> > Indeed. I can just drop the 32-bit mask test then. (But I'd retain the
> > error check anyway.)
> > 
> > The problem is that actual device DMA-addressing capability is
> > determined by the MASTER_BUS_ADDR_WIDTH IP-core synthesize parameter.
> > I can't predict its value from this generic code since it isn't
> > auto-detectable and is platform-specific. That's why back then in
> > our discussion I was insisting on setting the mask in the low-level
> > device drivers. But after the commit 423511ec23e2 ("PCI: dwc: Drop
> > dependency on ZONE_DMA32") it turned to be pointless now since the
> > DMA-mask would be overwritten by the generic DW PCIe driver code anyway.
> > What do you suggest then in this regard? Just keep setting the 64-bit
> > mask only? This will work for my platform, but will fail for the
> > devices with AXI-bus address of only 32-bits width.
> 
> OK, but you already have that problem either way. The point of
> dma_set_mask() et al is to inform the DMA API of your device's capability -
> setting a 64-bit mask is saying "I can use 64-bit addresses if you can" to
> the DMA layer, and as I say the DMA layer is almost always going to respond
> "indeed I can, let's do that". If the real DMA mask is platform-specific
> then you need to pass a platform-specific value here.
> 
> > > > > +			if (ret)
> > > > > +				return ret;
> > > > > +		}
> > > > > +
> > > > > +		if (dev_of_node(dev)) {
> > > > > +			struct device_node *node = dev_of_node(dev);
> > > > > +
> > > > > +			ret = of_dma_configure(&dchan->dev->device, node, true);
> > > > > +		} else if (has_acpi_companion(dev)) {
> > > 
> > 
> > > Can this can ever happen? AFAICS there's no ACPI binding to match and probe
> > > the DWC driver, at best it could only probe as a standard PNP0A08 host
> > > bridge which wouldn't know anything about eDMA anyway.
> > 
> > There are several ACPI-based platforms with DW PCIe controllers:
> > pcie-tegra194-acpi.c, pcie-al.c, pcie-hisi.c. All of them are fully
> > ECAM-based so no DW eDMA probing from the Linux kernel implied. But
> > these are still DW PCIe controllers and they or some other ones can
> > have eDMA embedded. Do you think it won't be ever possible to either
> > directly handle these controllers (bypassing the ECAM interface) or
> > have a DW PCIe device accessed via the ACPI bindings?
> 
> It's not entirely impossible, but would require new ACPI bindings and code
> changes to the dw-pci driver, so if somebody ever did do that work they
> should be responsible for any required changes at this end as well. There's
> no point adding untested dead code now, to maintain indefinitely just for
> the theoretical possibility that someone might ever make it reachable.
> 
> > Note basically what I've implemented here was based on the
> > platform_dma_configure() DMA-configuration code pattern. I thought it
> > was a reasonable choice since this code path is executed for the
> > platform devices only (implied by the DW_EDMA_CHIP_LOCAL flag
> > semantic).
> > 
> > On the second thought if the problem in subject is only specific to
> > the DT-based platforms, then I could just skip channel device
> > initialization here for the platform devices with no OF-node detected.
> > So the question is is it specific to the DT-based platforms only?
> 
> I think you still want the DW_EDMA_CHIP_LOCAL flag, since the PCI endpoint
> device in the dw-edma-pcie case may have an of_node on some platforms, and
> in that case overriding the chan_dma_dev setup would be wrong. When the flag
> is set, though, we can simply assume dev_of_node() is valid since it's the
> only possible way for that to happen (and if someone does ever break that
> assumption in future, it will likely make itself noticed).
> 
> > (Before answering to the question above please read the last comment
> > in this message.)
> > 
> > > 
> > > > > +			struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
> > > > > +
> > > > > +			ret = acpi_dma_configure(&dchan->dev->device,
> > > > > +						 acpi_get_dma_attr(adev));
> > > > > +		} else {
> > > > > +			ret = -EINVAL;
> > > > > +		}
> > > > > +
> > > > > +		if (ret)
> > > > > +			return ret;
> > > > > +
> > > > > +		if (dchan->dev->device.dma_range_map) {
> > > > > +			kfree(dchan->dev->device.dma_range_map);
> > > > > +			dchan->dev->device.dma_range_map = NULL;
> > > > > +		}
> > > 
> > 
> > > Ugh, I guess this is still here because now you're passing the channel
> > > device to of_dma_configure() such that it looks like a PCI child :(
> > 
> > No. It's still here because I successfully missed your email in my
> > work inbox so I thought you didn't fix that dma-ranges peculiarity of
> > the PCIe-host nodes.(
> > 
> > > 
> > > Can we just set "chan->dev->device.of_node = dev->of_node;" beforehand so it
> > > works as expected (with f1ad5338a4d5 in place) and we don't need to be
> > > messing with the dma_range_map details at all? Note that that isn't as hacky
> > > as it might sound - it's a relatively well-established practice in places
> > > like I2C and SPI, and in this case it seems perfectly appropriate
> > > semantically as well.
> > 
> > Of course we can. But now, thanks to your commit f1ad5338a4d5 ("of:
> > Fix "dma-ranges" handling for bus controllers"), there is no point in
> > any dma-ranges hack here because the dma-ranges property is no longer
> > parsed for the PCIe-host platform device. I can and will just drop the
> > custom DMA-channel device initialization from the patch. The only
> > issue left to solve is about setting the DMA-mask. Please see my notes
> > above regarding that problem.
> 

> Ah, I assumed you'd still want to keep the chan_dma_dev setup for the sake
> of independent DMA masks, at least until we get a better solution for the
> MSI stuff. If you're happy with the compromise of going back to using the
> real host device to keep things simple, that's fine by me.

My biggest concern was connected with the 'dma-ranges' problem. The
DMA-mask thing was another issue, but since the eDMA setup is executed
after the MSI setup we can just override the mask specified by the
later procedure. Though I'll have to add some loud comment regarding
that implicit order requirement.

In anyway thanks for your fix. I'll resubmit the series with the
DMA-mask overridden in the dw_edma_probe() method. The mask will be
calculated based on an additional flag specified in the
dw_edma_chip.flags field. It seems like the best solution at this
stage.

-Serge(y)

> 
> Thanks,
> Robin.