[PATCH] mtd: aspeed: fix compile warning in aspeed_smc_read_from_ahb()

[Marek Vasut]

On 02/09/2017 10:59 AM, Cédric Le Goater wrote:
> On 02/09/2017 10:05 AM, Marek Vasut wrote:
>> On 02/09/2017 12:37 AM, Brian Norris wrote:
>>> On Thu, Jan 19, 2017 at 10:13:18AM +0100, Cédric Le Goater wrote:
>>>> The first argument of ioread32_rep() and ioread8_rep is not
>>>> const. Change aspeed_smc_read_from_ahb() prototype to fix compile
>>>> warning :
>>>>
>>>>    drivers/mtd/spi-nor/aspeed-smc.c: In function 'aspeed_smc_read_from_ahb':
>>>>    drivers/mtd/spi-nor/aspeed-smc.c:212:16: warning: passing argument 1 of 'ioread32_rep' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
>>>>       ioread32_rep(src, buf, len >> 2);
>>>
>>> But why isn't that param constant? Seems like that's a bug in the
>>> ioread* APIs. Some of their implementations are const, but some are not.
>>>
>>> I see for instance that the implementation in lib/iomap.c is not const,
>>> where there's zero reason it shouldn't be (if we also fix, e.g., its
>>> mmio_insl()).
>>
>> Maybe it's worth fixing the ioread*_rep then ? Then again, that seems to
>> be way far off the scope of this patch.
> 
> Looking closer at where this comes from, the compile warning was 
> reported on x86 which pulls a different file for the definitions 
> of the ioread routines.

Well yes, intel is a special snowflake in the io accessor area.

> On x86, arch/x86/include/asm/io.h includes <asm-generic/iomap.h>
> which contains prototypes of the ioread routines without 'const'.
> 
> On ARM, arch/arm/include/asm/io.h includes <asm-generic/io.h>
> which contains the 'const' definitions.

Can you check if any of those arches needs it without const ?

> So may be, we should just drop that patch and fix iomap.h instead,
> but quite a few arches use it :
> 
> arch/sh/include/asm/io.h:#include <asm-generic/iomap.h>
> arch/mips/include/asm/io.h:#include <asm-generic/iomap.h>
> arch/ia64/include/asm/io.h:#include <asm-generic/iomap.h>
> arch/cris/include/asm/io.h:#include <asm-generic/iomap.h>
> arch/x86/include/asm/io.h:#include <asm-generic/iomap.h>
> arch/alpha/include/asm/io.h:#include <asm-generic/iomap.h>
> arch/powerpc/include/asm/io.h:#include <asm-generic/iomap.h>
> arch/m68k/include/asm/io_mm.h:#include <asm-generic/iomap.h>
> arch/m68k/include/asm/io_no.h:#include <asm-generic/iomap.h>
> arch/parisc/include/asm/io.h:#include <asm-generic/iomap.h>
> include/asm-generic/io.h:#include <asm-generic/iomap.h>
> 
> Thanks,
> 
> C.
> 


-- 
Best regards,
Marek Vasut