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ALSA: AACI: make fifo variables more explanitory

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Improve commenting and change fifo variable names to reflect their
meanings.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2011-01-13 22:25:10 +00:00
parent ea51d0b164
commit 5d350cba48
2 changed files with 26 additions and 20 deletions
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42
sound/arm/aaci.c
View File

@ -219,7 +219,7 @@ static void aaci_fifo_irq(struct aaci *aaci, int channel, u32 mask)
ptr = aacirun->ptr; ptr = aacirun->ptr;
do { do {
unsigned int len = aacirun->fifosz; unsigned int len = aacirun->fifo_bytes;
u32 val; u32 val;
if (aacirun->bytes <= 0) { if (aacirun->bytes <= 0) {
@ -279,7 +279,7 @@ static void aaci_fifo_irq(struct aaci *aaci, int channel, u32 mask)
ptr = aacirun->ptr; ptr = aacirun->ptr;
do { do {
unsigned int len = aacirun->fifosz; unsigned int len = aacirun->fifo_bytes;
u32 val; u32 val;
if (aacirun->bytes <= 0) { 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 * ALSA wants the byte-size of the FIFOs. As we only support
* mode, each 32-bit word contains one sample. If we're in * 16-bit samples, this is twice the FIFO depth irrespective
* compact mode, each 32-bit word contains two samples, effectively * of whether it's in compact mode or not.
* 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.
*/ */
runtime->hw.fifo_size = aaci->fifosize * 2; runtime->hw.fifo_size = aaci->fifo_depth * 2;
mutex_lock(&aaci->irq_lock); mutex_lock(&aaci->irq_lock);
if (!aaci->users++) { if (!aaci->users++) {
@ -529,10 +527,13 @@ static int aaci_pcm_hw_params(struct snd_pcm_substream *substream,
aacirun->pcm_open = err == 0; aacirun->pcm_open = err == 0;
aacirun->cr = CR_FEN | CR_COMPACT | CR_SZ16; aacirun->cr = CR_FEN | CR_COMPACT | CR_SZ16;
aacirun->cr |= channels_to_slotmask[channels + dbl * 2]; 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; return err;
@ -948,6 +949,10 @@ static unsigned int __devinit aaci_size_fifo(struct aaci *aaci)
struct aaci_runtime *aacirun = &aaci->playback; struct aaci_runtime *aacirun = &aaci->playback;
int i; 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); writel(CR_FEN | CR_SZ16 | CR_EN, aacirun->base + AACI_TXCR);
for (i = 0; !(readl(aacirun->base + AACI_SR) & SR_TXFF) && i < 4096; i++) 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); 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. * fifo depth.
*/ */
if (i == 4096) 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). * Size the FIFOs (must be multiple of 16).
* This is the number of entries in the FIFO.
*/ */
aaci->fifosize = aaci_size_fifo(aaci); aaci->fifo_depth = aaci_size_fifo(aaci);
if (aaci->fifosize & 15) { if (aaci->fifo_depth & 15) {
printk(KERN_WARNING "AACI: fifosize = %d not supported\n", printk(KERN_WARNING "AACI: FIFO depth %d not supported\n",
aaci->fifosize); aaci->fifo_depth);
ret = -ENODEV; ret = -ENODEV;
goto out; 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); ret = snd_card_register(aaci->card);
if (ret == 0) { if (ret == 0) {
dev_info(&dev->dev, "%s, fifo %d\n", aaci->card->longname, dev_info(&dev->dev, "%s\n", aaci->card->longname);
aaci->fifosize); dev_info(&dev->dev, "FIFO %u entries\n", aaci->fifo_depth);
amba_set_drvdata(dev, aaci->card); amba_set_drvdata(dev, aaci->card);
return ret; return ret;
} }

4
sound/arm/aaci.h
View File

@ -219,14 +219,14 @@ struct aaci_runtime {
void *end; void *end;
void *ptr; void *ptr;
int bytes; int bytes;
unsigned int fifosz; unsigned int fifo_bytes;
}; };
struct aaci { struct aaci {
struct amba_device *dev; struct amba_device *dev;
struct snd_card *card; struct snd_card *card;
void __iomem *base; void __iomem *base;
unsigned int fifosize; unsigned int fifo_depth;
unsigned int users; unsigned int users;
struct mutex irq_lock; struct mutex irq_lock;