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Date: Mon, 3 Sep 2012 14:00:11 +0530
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Subject: Re: [PATCH v4 2/3] dw_dmac: max_mem_width limits value for
 SRC/DST_TR_WID register
From: Viresh Kumar <viresh.kumar@linaro.org>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Hein Tibosch <hein_tibosch@yahoo.es>,
        Andrew Morton <akpm@linux-foundation.org>,
        Hans-Christian Egtvedt <egtvedt@samfundet.no>,
        Arnd Bergmann <arnd.bergmann@linaro.org>,
        spear-devel <spear-devel@list.st.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "ludovic.desroches" <ludovic.desroches@atmel.com>,
        Havard Skinnemoen <havard@skinnemoen.net>,
        Nicolas Ferre <nicolas.ferre@atmel.com>
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On 3 September 2012 13:55, Andy Shevchenko <andy.shevchenko@gmail.com> 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