[PATCH 6/6] driver core: initialize a default DMA mask for platform device

[Christoph Hellwig]

We still treat devices without a DMA mask as defaulting to 32-bits for
both mask, but a few releases ago we've started warning about such
cases, as they require special cases to work around this sloppyness.
Add a dma_mask field to struct platform_object so that we can initialize
the dma_mask pointer in struct device and initialize both masks to
32-bits by default.  Architectures can still override this in
arch_setup_pdev_archdata if needed.

Note that the code looks a little odd with the various conditionals
because we have to support platform_device structures that are
statically allocated.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 drivers/base/platform.c         | 15 +++++++++++++--
 include/linux/platform_device.h |  1 +
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index ec974ba9c0c4..b216fcb0a8af 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -264,6 +264,17 @@ struct platform_object {
        char name[];
 };
 
+static void setup_pdev_archdata(struct platform_device *pdev)
+{
+       if (!pdev->dev.coherent_dma_mask)
+               pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+       if (!pdev->dma_mask)
+               pdev->dma_mask = DMA_BIT_MASK(32);
+       if (!pdev->dev.dma_mask)
+               pdev->dev.dma_mask = &pdev->dma_mask;
+       arch_setup_pdev_archdata(pdev);
+};
+
 /**
  * platform_device_put - destroy a platform device
  * @pdev: platform device to free
@@ -310,7 +321,7 @@ struct platform_device *platform_device_alloc(const char 
*name, int id)
                pa->pdev.id = id;
                device_initialize(&pa->pdev.dev);
                pa->pdev.dev.release = platform_device_release;
-               arch_setup_pdev_archdata(&pa->pdev);
+               setup_pdev_archdata(&pa->pdev);
        }
 
        return pa ? &pa->pdev : NULL;
@@ -512,7 +523,7 @@ EXPORT_SYMBOL_GPL(platform_device_del);
 int platform_device_register(struct platform_device *pdev)
 {
        device_initialize(&pdev->dev);
-       arch_setup_pdev_archdata(pdev);
+       setup_pdev_archdata(pdev);
        return platform_device_add(pdev);
 }
 EXPORT_SYMBOL_GPL(platform_device_register);
diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index 9bc36b589827..a2abde2aef25 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -24,6 +24,7 @@ struct platform_device {
        int             id;
        bool            id_auto;
        struct device   dev;
+       u64             dma_mask;
        u32             num_resources;
        struct resource *resource;
 
-- 
2.20.1