Re: [PATCH 4/7] dmaengine: at_xdmac: adapt perid for mem2mem operations

From: Tudor.Ambarus
Date: Wed Sep 23 2020 - 01:35:43 EST


On 9/23/20 8:30 AM, Tudor Ambarus - M18064 wrote:
> On 9/14/20 5:09 PM, Eugen Hristev wrote:
>> The PERID in the CC register for mem2mem operations must match an unused
>> PERID.
>> The PERID field is 7 bits, but the selected value is 0x3f.
>> On later products we can have more reserved PERIDs for actual peripherals,
>> thus this needs to be increased to maximum size.
>> Changing the value to 0x7f, which is the maximum for 7 bits field.
>>
>
> Maybe it is worth to explain that for memory-to-memory transfers, PERID
> should be set to an unused peripheral ID, and the maximum value seems the
> safest. Anyway with or without this addressed, one can add:
>

:) I somehow misread your commit message, you already described that, it's fine.

> Reviewed-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
>
>> Signed-off-by: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx>
>> ---
>> drivers/dma/at_xdmac.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>