[lkml]   [2015]   [Dec]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 1/3] ata: sata_dwc_460ex: use "dmas" DT property to find dma channel
Andy Shevchenko <> writes:

> On Sun, Dec 20, 2015 at 10:17 PM, Andy Shevchenko
> <> wrote:
>> On Sun, Dec 20, 2015 at 8:49 PM, Måns Rullgård <> wrote:
>>> Julian Margetson <> writes:
>>>> On 12/20/2015 1:11 PM, Måns Rullgård wrote:
>>>>> Julian Margetson <> writes:
>>>> [ 48.769671] ata3.00: failed command: READ FPDMA QUEUED
>>> Well, that didn't help. I still think it's part of the problem, but
>>> something else must be wrong as well. The various Master Select fields
>>> look like a good place to start.
>> Master number (which is here would be either 1 or 0) should not affect
>> as long as they are connected to the same AHB bus (I would be
>> surprised if they are not).
>>> Also, the manual says the LLP_SRC_EN
>>> and LLP_DST_EN flags should be cleared on the last in a chain of blocks.
>>> The old sata_dwc driver does this whereas dw_dma does not.
>> Easy to fix, however I can't get how it might affect.
>>> It might be worthwhile to try reverting drivers/ata/sata_dwc_460ex.c to
>>> v4.0 (leaving the rest at 4.4-rc5) just to make sure that's a good
>>> reference. I've verified that this builds.
>> It would be nice.
>> I noticed thanks to DWC_PARAMS that burst size is hardcoded to 32
>> items on this board, however registers for SATA program it to 64. I
>> remember that I got no interrupt when I programmed transfer width
>> wrongly (64 bits against 32 bits) when I ported dw_dmac to be used on
>> Intel SoCs.
> One more thing, I have a patch to monitor DMA IO, we may check what
> exactly the values are written / read in DMA. I can share it
> tomorrow.
> P.S. I also noticed that original driver enables interrupt per each
> block

And then ignores all but the transfer complete interrupt.

> and sets protection control bits.

With no indication what the value it sets is supposed to mean.

Måns Rullgård

 \ /
  Last update: 2015-12-21 02:41    [W:0.192 / U:0.912 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site