Re: [PATCH v1] platform/x86: intel_pmc_ipc: fix division in 32-bit case

From: Andy Shevchenko
Date: Fri Feb 10 2017 - 07:03:13 EST


On Fri, Feb 10, 2017 at 6:24 AM, Rajneesh Bhardwaj
<rajneesh.bhardwaj@xxxxxxxxx> wrote:
> On Wed, Feb 08, 2017 at 06:00:28PM +0200, Andy Shevchenko wrote:
>> On 32-bit x86 platforms we can't do 64-bit divisions:
>>
>> ERROR: "__udivdi3" [drivers/platform/x86/intel_pmc_ipc.ko] undefined!
>>
>> Replace plain division by do_div() macro call.
>>
>> Reported-by: Darren Hart <dvhart@xxxxxxxxxxxxx>
>> Cc: Shanth Murthy <shanth.murthy@xxxxxxxxx>
>> Cc: Rajneesh Bhardwaj <rajneesh.bhardwaj@xxxxxxxxx>
>> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
>> ---
>> drivers/platform/x86/intel_pmc_ipc.c | 7 ++++++-
>> 1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/platform/x86/intel_pmc_ipc.c b/drivers/platform/x86/intel_pmc_ipc.c
>> index 46202b6e7c87..8ad4d7b43423 100644
>> --- a/drivers/platform/x86/intel_pmc_ipc.c
>> +++ b/drivers/platform/x86/intel_pmc_ipc.c
>> @@ -62,7 +62,12 @@
>> #define GCR_TELEM_SHLW_S0IX_OFFSET 0x1080
>>
>> /* Residency with clock rate at 19.2MHz to usecs */
>> -#define S0IX_RESIDENCY_IN_USECS(d, s) (((d) + (s)) * 10 / 192)
>> +#define S0IX_RESIDENCY_IN_USECS(d, s) \
>> +({ \
>> + u64 result = 10ull * ((d) + (s)); \
>> + do_div(result, 192); \
>> + result; \
>> +})
>>
>
> Looks good, we verified it. We are planning to squash this one and send V2.
> Hope thats fine?

Please, do!

--
With Best Regards,
Andy Shevchenko