[alsa-devel] [PATCH v3] dbri: Fix compiler warning

[David Miller]

From: Takashi Iwai <tiwai at suse.de>
Date: Fri, 25 Nov 2016 10:30:48 +0100

> On Thu, 24 Nov 2016 21:35:16 +0100,
> Tushar Dave wrote:
>> 
>> dbri uses 'u32' for dma handle while invoking kernel DMA APIs,
>> instead of using dma_addr_t. This hasn't caused any 'incompatible
>> pointer type' warning on SPARC because until now dma_addr_t is of
>> type u32. However, recent changes in SPARC ATU (iommu) enabled 64bit
>> DMA and therefore dma_addr_t became of type u64. This makes
>> 'incompatible pointer type' warnings inevitable.
>> 
>> e.g.
>> sound/sparc/dbri.c: In function ‘snd_dbri_create’:
>> sound/sparc/dbri.c:2538: warning: passing argument 3 of ‘dma_zalloc_coherent’ from incompatible pointer type
>> ./include/linux/dma-mapping.h:608: note: expected ‘dma_addr_t *’ but argument is of type ‘u32 *’
>> 
>> For the record, dbri(sbus) driver never executes on sun4v. Therefore
>> even though 64bit DMA is enabled on SPARC, dbri continues to use
>> legacy iommu that guarantees DMA address is always in 32bit range.
>> 
>> This patch resolves above compiler warning.
>> 
>> Signed-off-by: Tushar Dave <tushar.n.dave at oracle.com>
>> Reviewed-by: thomas tai <thomas.tai at oracle.com>
>> ---
>> v2->v3:
>> - Use %pad to print dma_addr_t. Comment by Takashi Iwai.
> 
> Applied now.  Thanks!

This patch is absolutely not appropriate for your tree Takashi.

It's for the sparc tree because that's where the dma_addr_t
type was changed from 32-bit to 64-bit on sparc64, which is
what caused this build warning.

Dave, please only send sparc specific driver patches to
sparclinux at vger.kernel.org in the future so we can avoid
this kind of problem.  The whole handling of the dma_addr_t
type change on sparc64 has been a real mess, quite honestly.