linux-kernel - Re: [PATCH v2 2/4] ALSA: hda: Rework snd_hdac_stream

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Date:   Wed, 05 Oct 2022 14:29:31 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     Jon Hunter <jonathanh@...dia.com>
Cc:     Amadeusz Sławiński 
        <amadeuszx.slawinski@...ux.intel.com>,
        Takashi Iwai <tiwai@...e.com>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org,
        Cezary Rojewski <cezary.rojewski@...el.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        "linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
        Mohan Kumar D <mkumard@...dia.com>
Subject: Re: [PATCH v2 2/4] ALSA: hda: Rework snd_hdac_stream_reset() to use macros

On Wed, 05 Oct 2022 14:10:04 +0200,
Jon Hunter wrote:
> 
> 
> On 18/08/2022 15:15, Amadeusz Sławiński wrote:
> > We can use existing macros to poll and update register values instead of
> > open coding the functionality.
> > 
> > Reviewed-by: Cezary Rojewski <cezary.rojewski@...el.com>
> > Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@...ux.intel.com>
> > ---
> >   sound/hda/hdac_stream.c | 26 ++++++--------------------
> >   1 file changed, 6 insertions(+), 20 deletions(-)
> > 
> > diff --git a/sound/hda/hdac_stream.c b/sound/hda/hdac_stream.c
> > index f3582012d22f..bdf6d4db6769 100644
> > --- a/sound/hda/hdac_stream.c
> > +++ b/sound/hda/hdac_stream.c
> > @@ -165,7 +165,6 @@ EXPORT_SYMBOL_GPL(snd_hdac_stop_streams_and_chip);
> >   void snd_hdac_stream_reset(struct hdac_stream *azx_dev)
> >   {
> >   	unsigned char val;
> > -	int timeout;
> >   	int dma_run_state;
> >     	snd_hdac_stream_clear(azx_dev);
> > @@ -173,30 +172,17 @@ void snd_hdac_stream_reset(struct hdac_stream *azx_dev)
> >   	dma_run_state = snd_hdac_stream_readb(azx_dev, SD_CTL) & SD_CTL_DMA_START;
> >     	snd_hdac_stream_updateb(azx_dev, SD_CTL, 0,
> > SD_CTL_STREAM_RESET);
> > -	udelay(3);
> > -	timeout = 300;
> > -	do {
> > -		val = snd_hdac_stream_readb(azx_dev, SD_CTL) &
> > -			SD_CTL_STREAM_RESET;
> > -		if (val)
> > -			break;
> > -	} while (--timeout);
> > +
> > +	/* wait for hardware to report that the stream entered reset */
> > +	snd_hdac_stream_readb_poll(azx_dev, SD_CTL, val, (val & SD_CTL_STREAM_RESET), 3, 300);
> >     	if (azx_dev->bus->dma_stop_delay && dma_run_state)
> >   		udelay(azx_dev->bus->dma_stop_delay);
> >   -	val &= ~SD_CTL_STREAM_RESET;
> > -	snd_hdac_stream_writeb(azx_dev, SD_CTL, val);
> > -	udelay(3);
> > +	snd_hdac_stream_updateb(azx_dev, SD_CTL, SD_CTL_STREAM_RESET, 0);
> >   -	timeout = 300;
> > -	/* waiting for hardware to report that the stream is out of reset */
> > -	do {
> > -		val = snd_hdac_stream_readb(azx_dev, SD_CTL) &
> > -			SD_CTL_STREAM_RESET;
> > -		if (!val)
> > -			break;
> > -	} while (--timeout);
> > +	/* wait for hardware to report that the stream is out of reset */
> > +	snd_hdac_stream_readb_poll(azx_dev, SD_CTL, val, !(val & SD_CTL_STREAM_RESET), 3, 300);
> >     	/* reset first position - may not be synced with hw at this
> > time */
> >   	if (azx_dev->posbuf)
> 
> 
> HDA playback is failing on -next for various Tegra boards. Bisect is
> point to this commit and reverting it fixes the problem. I was a bit
> puzzled why this change is causing a problem, but looking closer there
> is a difference between the previous code that was calling
> snd_hdac_stream_readb() and the new code that is calling
> snd_hdac_stream_readb_poll(). The function snd_hdac_stream_readb()
> calls snd_hdac_aligned_mmio() is see if the device has an aligned MMIO
> which Tegra does and then would call snd_hdac_aligned_read(). However,
> now the code always call readb() and this is breaking Tegra.
> 
> So it is either necessary to update snd_hdac_stream_readb_poll() to
> handle this or revert this change.

Does the patch below work?


thanks,

Takashi

-- 8< --
--- a/include/sound/hdaudio.h
+++ b/include/sound/hdaudio.h
@@ -592,8 +592,8 @@ int snd_hdac_get_stream_stripe_ctl(struct hdac_bus *bus,
 #define snd_hdac_stream_readb(dev, reg) \
 	snd_hdac_reg_readb((dev)->bus, (dev)->sd_addr + AZX_REG_ ## reg)
 #define snd_hdac_stream_readb_poll(dev, reg, val, cond, delay_us, timeout_us) \
-	readb_poll_timeout((dev)->sd_addr + AZX_REG_ ## reg, val, cond, \
-			   delay_us, timeout_us)
+	read_poll_timeout(snd_hdac_reg_readb, val, cond, delay_us, timeout_us,\
+			  false, (dev)->bus, (dev)->sd_addr + AZX_REG_ ## reg)
 #define snd_hdac_stream_readl_poll(dev, reg, val, cond, delay_us, timeout_us) \
 	readl_poll_timeout((dev)->sd_addr + AZX_REG_ ## reg, val, cond, \
 			   delay_us, timeout_us)