Re: [PATCH 1/3] ata: sata_dwc_460ex: use "dmas" DT property to find dma channel

[Andy Shevchenko]

On Sun, Dec 20, 2015 at 8:49 PM, MÃns RullgÃrd <mans@xxxxxxxxx> wrote:
> Julian Margetson <runaway@xxxxxxxx> writes:
>> On 12/20/2015 1:11 PM, MÃns RullgÃrd wrote:
>>> Julian Margetson <runaway@xxxxxxxx> 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.


-- 
With Best Regards,
Andy Shevchenko
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