From 5d350cba486de34eff99d0394d8fb436af54522e Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 13 Jan 2011 22:25:10 +0000 Subject: ALSA: AACI: make fifo variables more explanitory Improve commenting and change fifo variable names to reflect their meanings. Signed-off-by: Russell King --- sound/arm/aaci.c | 42 ++++++++++++++++++++++++------------------ sound/arm/aaci.h | 4 ++-- 2 files changed, 26 insertions(+), 20 deletions(-) (limited to 'sound/arm') diff --git a/sound/arm/aaci.c b/sound/arm/aaci.c index 393ce08b0e11..a148e275c80f 100644 --- a/sound/arm/aaci.c +++ b/sound/arm/aaci.c @@ -219,7 +219,7 @@ static void aaci_fifo_irq(struct aaci *aaci, int channel, u32 mask) ptr = aacirun->ptr; do { - unsigned int len = aacirun->fifosz; + unsigned int len = aacirun->fifo_bytes; u32 val; if (aacirun->bytes <= 0) { @@ -279,7 +279,7 @@ static void aaci_fifo_irq(struct aaci *aaci, int channel, u32 mask) ptr = aacirun->ptr; do { - unsigned int len = aacirun->fifosz; + unsigned int len = aacirun->fifo_bytes; u32 val; if (aacirun->bytes <= 0) { @@ -430,13 +430,11 @@ static int aaci_pcm_open(struct snd_pcm_substream *substream) } /* - * FIXME: ALSA specifies fifo_size in bytes. If we're in normal - * mode, each 32-bit word contains one sample. If we're in - * compact mode, each 32-bit word contains two samples, effectively - * halving the FIFO size. However, we don't know for sure which - * we'll be using at this point. We set this to the lower limit. + * ALSA wants the byte-size of the FIFOs. As we only support + * 16-bit samples, this is twice the FIFO depth irrespective + * of whether it's in compact mode or not. */ - runtime->hw.fifo_size = aaci->fifosize * 2; + runtime->hw.fifo_size = aaci->fifo_depth * 2; mutex_lock(&aaci->irq_lock); if (!aaci->users++) { @@ -529,10 +527,13 @@ static int aaci_pcm_hw_params(struct snd_pcm_substream *substream, aacirun->pcm_open = err == 0; aacirun->cr = CR_FEN | CR_COMPACT | CR_SZ16; aacirun->cr |= channels_to_slotmask[channels + dbl * 2]; - aacirun->fifosz = aaci->fifosize * 4; - if (aacirun->cr & CR_COMPACT) - aacirun->fifosz >>= 1; + /* + * fifo_bytes is the number of bytes we transfer to/from + * the FIFO, including padding. So that's x4. As we're + * in compact mode, the FIFO is half the size. + */ + aacirun->fifo_bytes = aaci->fifo_depth * 4 / 2; } return err; @@ -948,6 +949,10 @@ static unsigned int __devinit aaci_size_fifo(struct aaci *aaci) struct aaci_runtime *aacirun = &aaci->playback; int i; + /* + * Enable the channel, but don't assign it to any slots, so + * it won't empty onto the AC'97 link. + */ writel(CR_FEN | CR_SZ16 | CR_EN, aacirun->base + AACI_TXCR); for (i = 0; !(readl(aacirun->base + AACI_SR) & SR_TXFF) && i < 4096; i++) @@ -964,7 +969,7 @@ static unsigned int __devinit aaci_size_fifo(struct aaci *aaci) writel(aaci->maincr, aaci->base + AACI_MAINCR); /* - * If we hit 4096, we failed. Go back to the specified + * If we hit 4096 entries, we failed. Go back to the specified * fifo depth. */ if (i == 4096) @@ -1029,11 +1034,12 @@ static int __devinit aaci_probe(struct amba_device *dev, struct amba_id *id) /* * Size the FIFOs (must be multiple of 16). + * This is the number of entries in the FIFO. */ - aaci->fifosize = aaci_size_fifo(aaci); - if (aaci->fifosize & 15) { - printk(KERN_WARNING "AACI: fifosize = %d not supported\n", - aaci->fifosize); + aaci->fifo_depth = aaci_size_fifo(aaci); + if (aaci->fifo_depth & 15) { + printk(KERN_WARNING "AACI: FIFO depth %d not supported\n", + aaci->fifo_depth); ret = -ENODEV; goto out; } @@ -1046,8 +1052,8 @@ static int __devinit aaci_probe(struct amba_device *dev, struct amba_id *id) ret = snd_card_register(aaci->card); if (ret == 0) { - dev_info(&dev->dev, "%s, fifo %d\n", aaci->card->longname, - aaci->fifosize); + dev_info(&dev->dev, "%s\n", aaci->card->longname); + dev_info(&dev->dev, "FIFO %u entries\n", aaci->fifo_depth); amba_set_drvdata(dev, aaci->card); return ret; } diff --git a/sound/arm/aaci.h b/sound/arm/aaci.h index 198750d6871d..5791bd5bd2ab 100644 --- a/sound/arm/aaci.h +++ b/sound/arm/aaci.h @@ -219,14 +219,14 @@ struct aaci_runtime { void *end; void *ptr; int bytes; - unsigned int fifosz; + unsigned int fifo_bytes; }; struct aaci { struct amba_device *dev; struct snd_card *card; void __iomem *base; - unsigned int fifosize; + unsigned int fifo_depth; unsigned int users; struct mutex irq_lock; -- cgit v1.2.3