On Wednesday, June 03, 2015 at 11:26:39 PM, Michal Suchanek wrote:
> Hello,
Hi,
> this patch series makes it possible to access the SPI NOR flash in the
> Samsung XE303 'Snow' Chromebook.
>
> Unfortunately not all issues are resolved. To work around an issue with the
> pl330 dma engine I respun the patch for limiting transfer size in m25p80
> driver.
Looks like fixing a bug at the wrong place to me ...
> As the flash does not contain any sane filesystem and is only likely to be
> accessed with mtd_debug or similar tool the limit of the dma engine is
> easily reached. Filesystems using shorter data transfers are less likely
> to be affected.
Sounds like the DMA engine driver should be fixed.
Best regards,
Marek Vasut
On 4 June 2015 at 00:53, Marek Vasut <[email protected]> wrote:
> On Wednesday, June 03, 2015 at 11:26:39 PM, Michal Suchanek wrote:
>> Hello,
>
> Hi,
>
>> this patch series makes it possible to access the SPI NOR flash in the
>> Samsung XE303 'Snow' Chromebook.
>>
>> Unfortunately not all issues are resolved. To work around an issue with the
>> pl330 dma engine I respun the patch for limiting transfer size in m25p80
>> driver.
>
> Looks like fixing a bug at the wrong place to me ...
>
>> As the flash does not contain any sane filesystem and is only likely to be
>> accessed with mtd_debug or similar tool the limit of the dma engine is
>> easily reached. Filesystems using shorter data transfers are less likely
>> to be affected.
>
> Sounds like the DMA engine driver should be fixed.
I looked at the pl330 datasheet and don't see anything obviusly wrong
with the pl330 driver in Linux.
Ideally it would be fixed but I have no idea what's wrong with it.
Thanks
Michal
On Thursday, June 04, 2015 at 06:21:32 AM, Michal Suchanek wrote:
> On 4 June 2015 at 00:53, Marek Vasut <[email protected]> wrote:
> > On Wednesday, June 03, 2015 at 11:26:39 PM, Michal Suchanek wrote:
> >> Hello,
> >
> > Hi,
> >
> >> this patch series makes it possible to access the SPI NOR flash in the
> >> Samsung XE303 'Snow' Chromebook.
> >>
> >> Unfortunately not all issues are resolved. To work around an issue with
> >> the pl330 dma engine I respun the patch for limiting transfer size in
> >> m25p80 driver.
> >
> > Looks like fixing a bug at the wrong place to me ...
> >
> >> As the flash does not contain any sane filesystem and is only likely to
> >> be accessed with mtd_debug or similar tool the limit of the dma engine
> >> is easily reached. Filesystems using shorter data transfers are less
> >> likely to be affected.
> >
> > Sounds like the DMA engine driver should be fixed.
>
> I looked at the pl330 datasheet and don't see anything obviusly wrong
> with the pl330 driver in Linux.
>
> Ideally it would be fixed but I have no idea what's wrong with it.
Ask maybe Catalin from ARM to help you -- he might be able to point you
to the right hardware guy.
Best regards,
Marek Vasut