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authorRussell King <rmk+kernel@arm.linux.org.uk>2011-01-13 22:25:10 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-01-26 20:24:52 +0000
commit5d350cba486de34eff99d0394d8fb436af54522e (patch)
tree2acda06b2425eb5c2e2dd8b663dd5ce44170f273 /sound/arm
parentea51d0b164040ad594c1f9c4c6faf23c19c977b9 (diff)
downloadlinux-linaro-5d350cba486de34eff99d0394d8fb436af54522e.tar.gz
ALSA: AACI: make fifo variables more explanitory
Improve commenting and change fifo variable names to reflect their meanings. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'sound/arm')
-rw-r--r--sound/arm/aaci.c42
-rw-r--r--sound/arm/aaci.h4
2 files changed, 26 insertions, 20 deletions
diff --git a/sound/arm/aaci.c b/sound/arm/aaci.c
index 393ce08b0e1..a148e275c80 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 198750d6871..5791bd5bd2a 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;