Re: [PATCH v4 2/3] dw_dmac: max_mem_width limits value forSRC/DST_TR_WID register

From: Viresh Kumar
Date: Mon Sep 03 2012 - 04:30:06 EST


On 3 September 2012 13:55, Andy Shevchenko <andy.shevchenko@xxxxxxxxx> wrote:
>> #define DW_MEM_WIDTH_64 0 /* default */
>> #define DW_MEM_WIDTH_32 1 /* e.g. for avr32 */
> There are 4 options: 32, 64, 128, and 256 bits. I would prefer to see
> the value in conjunction with
> real value in the register, namely 2 for 32, 3 - 64, 4 - 128, 5 - 256.

Which register are you talking about? This configuration is outside of DMAC
controller and i am not sure if dw DMAC controller can do 128 or 256
bit transfers.

>> @@ -58,6 +58,9 @@ struct dw_dma_slave {
>> u32 cfg_lo;
>> u8 src_master;
>> u8 dst_master;
>> +#define DW_MEM_WIDTH_64 0
>> +#define DW_MEM_WIDTH_32 1 /* e.g. for avr32 */
>> + u8 max_mem_width;
> Might be I missed something, but why is it slave configuration?
> I think the controller (actually channel) structure is more suitable
> to keep that field inside.

@Hein: Even i missed it. How will you do memcpy transfers as we don't have
this structure there. Probably you need to move this to DMA controller platform
data filed.

viresh
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