Re: [PATCH v1] alpha: io: Make sparse happy about bitwise types

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Thu, Jun 18, 2020 at 04:51:17PM +0300, Andy Shevchenko wrote:
> On Alpha the IO accessors are using plain unsigned types, such as uXX.
> But Alpha can be configured to any endianess and implementation of
> BE IO accessors, such as iowrite32be(), require endianess conversion.
> This conversion, when done via cpu_to*() and *_to_cpu() helpers, uses
> bitwise types of which sparse is not happy.
> 
> 8250_dwlib.c:45:17: sparse: sparse: incorrect type in argument 1 (different base types)
> 8250_dwlib.c:45:17: sparse:     expected unsigned int [usertype]
> 8250_dwlib.c:45:17: sparse:     got restricted __be32 [usertype]
> 
> One way is to use a lot of ifdeffery to properly use swab*() combination with
> writel() or so, another is much simpler, i.e. forcing types, especially taking
> into consideration the commit message of the original commit for that API.

Any comment on this so far?

> Fixes: 25534eb77078 ("alpha: add io{read,write}{16,32}be functions")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  arch/alpha/include/asm/io.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/alpha/include/asm/io.h b/arch/alpha/include/asm/io.h
> index a4d0c19f1e79..9529656c24bb 100644
> --- a/arch/alpha/include/asm/io.h
> +++ b/arch/alpha/include/asm/io.h
> @@ -491,8 +491,8 @@ extern inline void writeq(u64 b, volatile void __iomem *addr)
>  
>  #define ioread16be(p) be16_to_cpu(ioread16(p))
>  #define ioread32be(p) be32_to_cpu(ioread32(p))
> -#define iowrite16be(v,p) iowrite16(cpu_to_be16(v), (p))
> -#define iowrite32be(v,p) iowrite32(cpu_to_be32(v), (p))
> +#define iowrite16be(v,p) iowrite16((__force u16)cpu_to_be16(v), (p))
> +#define iowrite32be(v,p) iowrite32((__force u32)cpu_to_be32(v), (p))
>  
>  #define inb_p		inb
>  #define inw_p		inw
> -- 
> 2.27.0.rc2
> 

-- 
With Best Regards,
Andy Shevchenko