[alsa-devel] DW-DMA: Probe failures on broadwell

[Andy Shevchenko]

On Tue, Jul 09, 2019 at 12:27:49PM -0700, Curtis Malainey wrote:
> Hi Andy,

Please, don't top post in the public mailing lists, community doesn't like it.

> Thanks for the information, we are running a 4.14 kernel so we don't
> have the idma32 driver, I will see if I can backport it and report
> back if the fix works.

Driver is supporting iDMA 32-bit in v4.14 AFAICS.
The missed stuff is a split and some fixes here and there.
Here is the list of patches I have in a range v4.14..v5.2
(I deliberately dropped the insignificant ones)

934891b0a16c dmaengine: dw: Don't pollute CTL_LO on iDMA 32-bit
91f0ff883e9a dmaengine: dw: Reset DRAIN bit when resume the channel
69da8be90d5e dmaengine: dw: Split DW and iDMA 32-bit operations
87fe9ae84d7b dmaengine: dw: Add missed multi-block support for iDMA 32-bit
ffe843b18211 dmaengine: dw: Fix FIFO size for Intel Merrifield
7b0c03ecc42f dmaengine: dw-dmac: implement dma protection control setting

For me sounds like fairly easy to backport.

> On Tue, Jul 9, 2019 at 6:38 AM Andy Shevchenko
> <andriy.shevchenko at linux.intel.com> wrote:
> >
> > On Tue, Jul 09, 2019 at 04:34:48PM +0300, Andy Shevchenko wrote:
> > > On Tue, Jul 09, 2019 at 04:29:43PM +0300, Andy Shevchenko wrote:
> > > > On Tue, Jul 09, 2019 at 04:14:01PM +0300, Andy Shevchenko wrote:
> > > > > On Mon, Jul 08, 2019 at 01:50:07PM -0700, Curtis Malainey wrote:
> > > >
> > > > > So, the correct fix is to provide a platform data, like it's done in
> > > > > drivers/dma/dw/pci.c::idma32_pdata, in the sst-firmware.c::dw_probe(), and call
> > > > > idma32_dma_probe() with idma32_dma_remove() respectively on removal stage.
> > > > >
> > > > > (It will require latest patches to be applied, which are material for v5.x)
> > > >
> > > > Below completely untested patch to try
> > >
> > > Also, it might require to set proper request lines (currently it uses 0 AFAICS).
> > > Something like it's done in drivers/spi/spi-pxa2xx-pci.c for Intel Merrifield.
> >
> > And SST_DSP_DMA_MAX_BURST seems encoded while it's should be simple number,
> > like 8 (bytes). Also SPI PXA is an example to look into.
> >
> > I doubt it has been validated with upstream driver (I know about some internal
> > drivers, hacked version of dw one, you may find sources somewhere in public).

-- 
With Best Regards,
Andy Shevchenko