[PATCH] arm64: Implement arch_setup_pdev_archdata hook

On 7 June 2016 at 17:15, Robin Murphy [off-list ref] wrote:

On 07/06/16 09:29, Baolin Wang wrote:

quoted

Now on ARM64 platform, it will set 'dummy_dma_ops' for device dma_ops if
it did not call 'arch_setup_dma_ops' at device creation time by issuing
platform_device_alloc() function, that will cause failure when setting
the dma mask for device.

Yes, that's rather the whole point. DMA-capable devices are real hardware,
therefore don't spring out of thin air without being described in DT or
ACPI.

OK.

Please elaborate on the situation that you're attempting to address here
(please don't let it be the ongoing Designware USB catastrophe ;))

Yes, like you mentioned, we met problems at DesignWare USB3 controller
host glue, do you have any better solutions to solve this problem?
Thanks.

Robin.

quoted

Hence We need to hook the archdata to setup proper dma_ops for these
devices.

Signed-off-by: Baolin Wang <redacted>
---
  arch/arm64/mm/dma-mapping.c |   21 +++++++++++++++++++++
  1 file changed, 21 insertions(+)

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index c566ec8..04e057b 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c

@@ -26,6 +26,7 @@
  #include <linux/dma-contiguous.h>
  #include <linux/vmalloc.h>
  #include <linux/swiotlb.h>
+#include <linux/platform_device.h>

  #include <asm/cacheflush.h>

@@ -961,3 +962,23 @@ void arch_setup_dma_ops(struct device *dev, u64

dma_base, u64 size,
        dev->archdata.dma_coherent = coherent;
        __iommu_setup_dma_ops(dev, dma_base, size, iommu);
  }
+
+void arch_setup_pdev_archdata(struct platform_device *pdev)
+{
+       if (!pdev->dev.archdata.dma_ops)
+               pdev->dev.archdata.dma_ops = &swiotlb_dma_ops;
+
+       /*
+        * Set default coherent_dma_mask to 32 bit. Drivers are expected
to
+        * setup the correct supported mask.
+        */
+       if (!pdev->dev.coherent_dma_mask)
+               pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+
+       /*
+        * Set it to coherent_dma_mask by default if the architecture
+        * code has not set it.
+        */
+       if (!pdev->dev.dma_mask)
+               pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
+}

-- 
Baolin.wang
Best Regards