Subject: Re: [PATCH] ASoC: fsl_dma: Pass the proper device for dma mapping routines

From: Anton Vorontsov <[email-masked]>
Date: Sun, 5 Apr 2009 12:52:43 +0400

On Sat, Apr 04, 2009 at 11:59:39PM -0600, Grant Likely wrote:
> Becky & Kumar,
> 
> Considering these fixups, would it be advisable for the dma functions
> to climb up the dev->parent linkage when dma_ops are NULL?

pcm->dev->parent doesn't point to the proper device, so
this won't work.

> On Sat, Apr 4, 2009 at 12:33 PM, Anton Vorontsov
> <[email-masked]> wrote:
> > The driver should pass a device that specifies internal DMA ops, but
> > substream->pcm is just a logical device, and thus doesn't have arch-
> > specific dma callbacks, therefore following bug appears:
> >
> >  Freescale Synchronous Serial Interface (SSI) ASoC Driver
> >  ------------[ cut here ]------------
> >  kernel BUG at arch/powerpc/include/asm/dma-mapping.h:237!
> >  Oops: Exception in kernel mode, sig: 5 [#1]
> >  ...
> >  NIP [c02259c4] snd_malloc_dev_pages+0x58/0xac
> >  LR [c0225c74] snd_dma_alloc_pages+0xf8/0x108
> >  Call Trace:
> >  [df02bde0] [df02be2c] 0xdf02be2c (unreliable)
> >  [df02bdf0] [c0225c74] snd_dma_alloc_pages+0xf8/0x108
> >  [df02be10] [c023a100] fsl_dma_new+0x68/0x124
> >  [df02be20] [c02342ac] soc_new_pcm+0x1bc/0x234
> >  [df02bea0] [c02343dc] snd_soc_new_pcms+0xb8/0x148
> >  [df02bed0] [c023824c] cs4270_probe+0x34/0x124
> >  [df02bef0] [c0232fe8] snd_soc_instantiate_card+0x1a4/0x2f4
> >  [df02bf20] [c0233164] snd_soc_instantiate_cards+0x2c/0x68
> >  [df02bf30] [c0234704] snd_soc_register_platform+0x60/0x80
> >  [df02bf50] [c03d5664] fsl_soc_platform_init+0x18/0x28
> >  ...
> >
> > This patch fixes the issue by using card's device instead.
> >
> > Signed-off-by: Anton Vorontsov <[email-masked]>
> > ---
> >  sound/soc/fsl/fsl_dma.c |   12 ++++++------
> >  1 files changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/sound/soc/fsl/fsl_dma.c b/sound/soc/fsl/fsl_dma.c
> > index b3eb857..835e43c 100644
> > --- a/sound/soc/fsl/fsl_dma.c
> > +++ b/sound/soc/fsl/fsl_dma.c
> > @@ -300,7 +300,7 @@ static int fsl_dma_new(struct snd_card *card, struct snd_soc_dai *dai,
> >        if (!card->dev->coherent_dma_mask)
> >                card->dev->coherent_dma_mask = fsl_dma_dmamask;
> >
> > -       ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->dev,
> > +       ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, card->dev,
> >                fsl_dma_hardware.buffer_bytes_max,
> >                &pcm->streams[0].substream->dma_buffer);
> >        if (ret) {
> > @@ -310,7 +310,7 @@ static int fsl_dma_new(struct snd_card *card, struct snd_soc_dai *dai,
> >                return -ENOMEM;
> >        }
> >
> > -       ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->dev,
> > +       ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, card->dev,
> >                fsl_dma_hardware.buffer_bytes_max,
> >                &pcm->streams[1].substream->dma_buffer);
> >        if (ret) {
> > @@ -418,7 +418,7 @@ static int fsl_dma_open(struct snd_pcm_substream *substream)
> >                return -EBUSY;
> >        }
> >
> > -       dma_private = dma_alloc_coherent(substream->pcm->dev,
> > +       dma_private = dma_alloc_coherent(substream->pcm->card->dev,
> >                sizeof(struct fsl_dma_private), &ld_buf_phys, GFP_KERNEL);
> >        if (!dma_private) {
> >                dev_err(substream->pcm->card->dev,
> > @@ -445,7 +445,7 @@ static int fsl_dma_open(struct snd_pcm_substream *substream)
> >                dev_err(substream->pcm->card->dev,
> >                        "can't register ISR for IRQ %u (ret=%i)\n",
> >                        dma_private->irq, ret);
> > -               dma_free_coherent(substream->pcm->dev,
> > +               dma_free_coherent(substream->pcm->card->dev,
> >                        sizeof(struct fsl_dma_private),
> >                        dma_private, dma_private->ld_buf_phys);
> >                return ret;
> > @@ -761,13 +761,13 @@ static int fsl_dma_close(struct snd_pcm_substream *substream)
> >                        free_irq(dma_private->irq, dma_private);
> >
> >                if (dma_private->ld_buf_phys) {
> > -                       dma_unmap_single(substream->pcm->dev,
> > +                       dma_unmap_single(substream->pcm->card->dev,
> >                                dma_private->ld_buf_phys,
> >                                sizeof(dma_private->link), DMA_TO_DEVICE);
> >                }
> >
> >                /* Deallocate the fsl_dma_private structure */
> > -               dma_free_coherent(substream->pcm->dev,
> > +               dma_free_coherent(substream->pcm->card->dev,
> >                        sizeof(struct fsl_dma_private),
> >                        dma_private, dma_private->ld_buf_phys);
> >                substream->runtime->private_data = NULL;
> > --
> > 1.5.6.5
> > _______________________________________________
> > Linuxppc-dev mailing list
> > [email-masked]
> > https://ozlabs.org/mailman/listinfo/linuxppc-dev
> >
> 
> 
> 
> -- 
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.

-- 
Anton Vorontsov
email: [email-masked]
irc://irc.freenode.net/bd2