[PATCH v2 02/21] armv7m: cache: add mmu_set_region_dcache_behaviour() stub for compatibility

[Giulio Benetti]

On 1/28/20 9:10 AM, Lukasz Majewski wrote:
> Hi Giulio,
> 
>> Since some driver
> 
> I would prefer more verbose commit message. Please share which driver
> requires this change.

Yes, you were right, this is a quite dumb commit log.

Now commit log can't be changed, anyway this is the list of drivers that 
use it:
drivers/video/mvebu_lcd.c
drivers/video/mxsfb.c (that I'm going to use soon)
drivers/video/bcm2835.c
drivers/video/fsl_dcu_fb.c
drivers/video/tegra.c
drivers/video/imx/mxc_ipuv3_fb.c

drivers/net/zynq_gem.c
drivers/net/mvneta.c
drivers/net/mvpp2.c

And this function prototype is provided by arch/arm/include/asm/system.h

Everything came out when I've tried to build mxsfb.c.

But after this e-mail I've dug deeper and see that sometimes 
mmu_set_region_dcache_behaviour() call is guarded by 
CONFIG_IS_ENABLED(SYS_DCACHE_OFF) and sometimes i.e. 
arch/arm/cpu/armv8/cache_v8.c that function is defined both implemented 
and empty according to CONFIG_IS_ENABLED(SYS_DCACHE_OFF). So one chance 
is to put a check to guard against CONFIG_IS_ENABLED(SYS_DCACHE_OFF) on 
every call(the files listed above), otherwise, where is guarded we 
should remove the guard and adding missing 
mmu_set_region_dcache_behaviour() empty implementation. ~5 files to 
touch, but if you say it's worth, I can do patches for that, and I don't 
see any drawbacks expect having a standard way on dealing with the cache 
function.

What about that?

Kind regards
-- 
Giulio Benetti
Benetti Engineering sas

>> requires this function add it as an empty stub
>> when DCACHE is OFF.
>>
>> Signed-off-by: Giulio Benetti <giulio.benetti at benettiengineering.com>
>> ---
>>   arch/arm/cpu/armv7m/cache.c | 6 ++++++
>>   1 file changed, 6 insertions(+)
>>
>> diff --git a/arch/arm/cpu/armv7m/cache.c b/arch/arm/cpu/armv7m/cache.c
>> index f4ba3ad50e..7353698557 100644
>> --- a/arch/arm/cpu/armv7m/cache.c
>> +++ b/arch/arm/cpu/armv7m/cache.c
>> @@ -291,6 +291,12 @@ void flush_dcache_all(void)
>>   void invalidate_dcache_all(void)
>>   {
>>   }
>> +
>> +void mmu_set_region_dcache_behaviour(phys_addr_t start, size_t size,
>> +				     enum dcache_option option)
>> +{
>> +}
>> +
>>   #endif
>>   
>>   #if !CONFIG_IS_ENABLED(SYS_ICACHE_OFF)
> 
> 
> Best regards,
> 
> Lukasz Majewski
> 
> --
> 
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