Hi Arnd,

On 04/04/18 11:23, Arnd Bergmann wrote:
We get a build error when compiling the iommu driver without CONFIG_OF:

drivers/iommu/rockchip-iommu.c: In function 'rk_iommu_of_xlate':
drivers/iommu/rockchip-iommu.c:1101:2: error: implicit declaration of function 
'of_dev_put'; did you mean 'of_node_put'? 

This replaces the of_dev_put() with the equivalent platform_device_put(),
and adds an error check for of_find_device_by_node() returning NULL,
which seems to be appropriate here given that we pass the device into
platform_get_drvdata() next, and that of_find_device_by_node() might
theoretically return a NULL pointer.

Fixes: 5fd577c3eac3 ("iommu/rockchip: Use OF_IOMMU to attach devices 
Signed-off-by: Arnd Bergmann <a...@arndb.de>
This warning appears to only have been introduced in linux-next after
the merge window opened.
  drivers/iommu/rockchip-iommu.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 5fc8656c60f9..fe9c9cc1a9d4 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -1094,11 +1094,15 @@ static int rk_iommu_of_xlate(struct device *dev,
                return -ENOMEM;
iommu_dev = of_find_device_by_node(args->np);
+       if (!iommu_dev) {

Actually, though the logic is perhaps a bit subtle, this cannot reasonably happen - .of_xlate is only called via a set of iommu_ops associated with the IOMMU node (args->np here); those ops are only registered for the given node at the end of rk_iommu_probe(), by which point the IOMMU device exists and is otherwise successfully probed, so the platform bus lookup should never be able to fail.

+               kfree(data);
+               return -ENODEV;
+       }
data->iommu = platform_get_drvdata(iommu_dev);
        dev->archdata.iommu = data;
- of_dev_put(iommu_dev);
+       platform_device_put(iommu_dev);

This bit looks reasonable, thanks for the fix.


return 0;

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