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driver core: platform: Initialize dma_parms for platform devices
authorUlf Hansson <ulf.hansson@linaro.org>
Wed, 22 Apr 2020 10:09:54 +0000 (12:09 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 28 Apr 2020 15:44:33 +0000 (17:44 +0200)
commit9495b7e92f716ab2bd6814fab5e97ab4a39adfdd
treea35e414bccd3555ce17ac97c68e704e3eecf3453
parent6a8b55ed4056ea5559ebe4f6a4b247f627870d4c
driver core: platform: Initialize dma_parms for platform devices

It's currently the platform driver's responsibility to initialize the
pointer, dma_parms, for its corresponding struct device. The benefit with
this approach allows us to avoid the initialization and to not waste memory
for the struct device_dma_parameters, as this can be decided on a case by
case basis.

However, it has turned out that this approach is not very practical.  Not
only does it lead to open coding, but also to real errors. In principle
callers of dma_set_max_seg_size() doesn't check the error code, but just
assumes it succeeds.

For these reasons, let's do the initialization from the common platform bus
at the device registration point. This also follows the way the PCI devices
are being managed, see pci_device_add().

Suggested-by: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org>
Tested-by: Haibo Chen <haibo.chen@nxp.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20200422100954.31211-1-ulf.hansson@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/base/platform.c
include/linux/platform_device.h