[alsa-devel] [PATCH] ASoC: rcar: revert IOMMU support so far
Takashi Iwai
tiwai at suse.de
Thu Nov 16 08:21:20 CET 2017
On Thu, 16 Nov 2017 05:36:51 +0100,
Kuninori Morimoto wrote:
>
>
> From: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
>
> commit 4821d914fe74 ("ASoC: rsnd: use dma_sync_single_for_xxx() for
> IOMMU") had supported IOMMU, but it breaks normal sound "recorde"
> and both PulseAudio's "playback/recorde". The sound will be noisy.
>
> That commit was using dma_sync_single_for_xxx(), and driver should
> make sure memory is protected during CPU or Device are using it.
> But if driver returns current "residue" data size correctly on pointer
> function, player/recorder will access to protected memory.
>
> IOMMU feature should be supported, but I don't know how to handle it
> without memory cache problem at this point.
> Thus, this patch simply revert it to avoid current noisy sound.
The driver may return the position at the last synced point via
pointer callback while keeping the finer position by compensating with
status delay field. In that way, user-space can avoid to touch the
in-flight memory but can know the exact position.
BTW, if the problem is only about PA, the easiest workaround would be
to put SNDRV_PCM_INFO_BATCH flag. Then PA switches from tsched to
normal mode.
thanks,
Takashi
>
> Tested-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx at renesas.com>
> Tested-by: Ryo Kodama <ryo.kodama.vz at renesas.com>
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
> ---
> sound/soc/sh/rcar/core.c | 4 +--
> sound/soc/sh/rcar/dma.c | 86 ++++--------------------------------------------
> 2 files changed, 8 insertions(+), 82 deletions(-)
>
> diff --git a/sound/soc/sh/rcar/core.c b/sound/soc/sh/rcar/core.c
> index 8cd900d..ebdfa34 100644
> --- a/sound/soc/sh/rcar/core.c
> +++ b/sound/soc/sh/rcar/core.c
> @@ -1329,8 +1329,8 @@ static int rsnd_pcm_new(struct snd_soc_pcm_runtime *rtd)
>
> return snd_pcm_lib_preallocate_pages_for_all(
> rtd->pcm,
> - SNDRV_DMA_TYPE_CONTINUOUS,
> - snd_dma_continuous_data(GFP_KERNEL),
> + SNDRV_DMA_TYPE_DEV,
> + rtd->card->snd_card->dev,
> PREALLOC_BUFFER, PREALLOC_BUFFER_MAX);
> }
>
> diff --git a/sound/soc/sh/rcar/dma.c b/sound/soc/sh/rcar/dma.c
> index fd557ab..4d750bdf 100644
> --- a/sound/soc/sh/rcar/dma.c
> +++ b/sound/soc/sh/rcar/dma.c
> @@ -26,10 +26,7 @@
> struct rsnd_dmaen {
> struct dma_chan *chan;
> dma_cookie_t cookie;
> - dma_addr_t dma_buf;
> unsigned int dma_len;
> - unsigned int dma_period;
> - unsigned int dma_cnt;
> };
>
> struct rsnd_dmapp {
> @@ -71,38 +68,10 @@ struct rsnd_dma_ctrl {
> /*
> * Audio DMAC
> */
> -#define rsnd_dmaen_sync(dmaen, io, i) __rsnd_dmaen_sync(dmaen, io, i, 1)
> -#define rsnd_dmaen_unsync(dmaen, io, i) __rsnd_dmaen_sync(dmaen, io, i, 0)
> -static void __rsnd_dmaen_sync(struct rsnd_dmaen *dmaen, struct rsnd_dai_stream *io,
> - int i, int sync)
> -{
> - struct device *dev = dmaen->chan->device->dev;
> - enum dma_data_direction dir;
> - int is_play = rsnd_io_is_play(io);
> - dma_addr_t buf;
> - int len, max;
> - size_t period;
> -
> - len = dmaen->dma_len;
> - period = dmaen->dma_period;
> - max = len / period;
> - i = i % max;
> - buf = dmaen->dma_buf + (period * i);
> -
> - dir = is_play ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
> -
> - if (sync)
> - dma_sync_single_for_device(dev, buf, period, dir);
> - else
> - dma_sync_single_for_cpu(dev, buf, period, dir);
> -}
> -
> static void __rsnd_dmaen_complete(struct rsnd_mod *mod,
> struct rsnd_dai_stream *io)
> {
> struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
> - struct rsnd_dma *dma = rsnd_mod_to_dma(mod);
> - struct rsnd_dmaen *dmaen = rsnd_dma_to_dmaen(dma);
> bool elapsed = false;
> unsigned long flags;
>
> @@ -115,22 +84,9 @@ static void __rsnd_dmaen_complete(struct rsnd_mod *mod,
> */
> spin_lock_irqsave(&priv->lock, flags);
>
> - if (rsnd_io_is_working(io)) {
> - rsnd_dmaen_unsync(dmaen, io, dmaen->dma_cnt);
> -
> - /*
> - * Next period is already started.
> - * Let's sync Next Next period
> - * see
> - * rsnd_dmaen_start()
> - */
> - rsnd_dmaen_sync(dmaen, io, dmaen->dma_cnt + 2);
> -
> + if (rsnd_io_is_working(io))
> elapsed = true;
>
> - dmaen->dma_cnt++;
> - }
> -
> spin_unlock_irqrestore(&priv->lock, flags);
>
> if (elapsed)
> @@ -165,14 +121,8 @@ static int rsnd_dmaen_stop(struct rsnd_mod *mod,
> struct rsnd_dma *dma = rsnd_mod_to_dma(mod);
> struct rsnd_dmaen *dmaen = rsnd_dma_to_dmaen(dma);
>
> - if (dmaen->chan) {
> - int is_play = rsnd_io_is_play(io);
> -
> + if (dmaen->chan)
> dmaengine_terminate_all(dmaen->chan);
> - dma_unmap_single(dmaen->chan->device->dev,
> - dmaen->dma_buf, dmaen->dma_len,
> - is_play ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
> - }
>
> return 0;
> }
> @@ -237,11 +187,7 @@ static int rsnd_dmaen_start(struct rsnd_mod *mod,
> struct device *dev = rsnd_priv_to_dev(priv);
> struct dma_async_tx_descriptor *desc;
> struct dma_slave_config cfg = {};
> - dma_addr_t buf;
> - size_t len;
> - size_t period;
> int is_play = rsnd_io_is_play(io);
> - int i;
> int ret;
>
> cfg.direction = is_play ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;
> @@ -258,19 +204,10 @@ static int rsnd_dmaen_start(struct rsnd_mod *mod,
> if (ret < 0)
> return ret;
>
> - len = snd_pcm_lib_buffer_bytes(substream);
> - period = snd_pcm_lib_period_bytes(substream);
> - buf = dma_map_single(dmaen->chan->device->dev,
> - substream->runtime->dma_area,
> - len,
> - is_play ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
> - if (dma_mapping_error(dmaen->chan->device->dev, buf)) {
> - dev_err(dev, "dma map failed\n");
> - return -EIO;
> - }
> -
> desc = dmaengine_prep_dma_cyclic(dmaen->chan,
> - buf, len, period,
> + substream->runtime->dma_addr,
> + snd_pcm_lib_buffer_bytes(substream),
> + snd_pcm_lib_period_bytes(substream),
> is_play ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
> DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
>
> @@ -282,18 +219,7 @@ static int rsnd_dmaen_start(struct rsnd_mod *mod,
> desc->callback = rsnd_dmaen_complete;
> desc->callback_param = rsnd_mod_get(dma);
>
> - dmaen->dma_buf = buf;
> - dmaen->dma_len = len;
> - dmaen->dma_period = period;
> - dmaen->dma_cnt = 0;
> -
> - /*
> - * synchronize this and next period
> - * see
> - * __rsnd_dmaen_complete()
> - */
> - for (i = 0; i < 2; i++)
> - rsnd_dmaen_sync(dmaen, io, i);
> + dmaen->dma_len = snd_pcm_lib_buffer_bytes(substream);
>
> dmaen->cookie = dmaengine_submit(desc);
> if (dmaen->cookie < 0) {
> --
> 1.9.1
>
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