On 2018-12-21 17:44, Chen-Yu Tsai wrote:
On Fri, Dec 21, 2018 at 11:21 PM codekipper@gmail.com wrote:
From: Marcus Cooper codekipper@gmail.com
Bypass the regmap cache when flushing the i2s FIFOs and modify the tables to reflect this.
Signed-off-by: Marcus Cooper codekipper@gmail.com
sound/soc/sunxi/sun4i-i2s.c | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-)
diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c index d5ec1a20499d..64d073cb2aee 100644 --- a/sound/soc/sunxi/sun4i-i2s.c +++ b/sound/soc/sunxi/sun4i-i2s.c @@ -548,9 +548,11 @@ static int sun4i_i2s_set_fmt(struct snd_soc_dai *dai, unsigned int fmt) static void sun4i_i2s_start_capture(struct sun4i_i2s *i2s) { /* Flush RX FIFO */
regcache_cache_bypass(i2s->regmap, true); regmap_update_bits(i2s->regmap, SUN4I_I2S_FIFO_CTRL_REG, SUN4I_I2S_FIFO_CTRL_FLUSH_RX, SUN4I_I2S_FIFO_CTRL_FLUSH_RX);regcache_cache_bypass(i2s->regmap, false);IIRC the flush cache bit is self-clearing. So you likely want to mark this register as volatile. If it is marked as volatile, then all access to that register bypasses the cache, so the regcache_cache_bypass calls are unneeded.
I helped test this together with Marcus and when I tested with this register marked as volatile audio started to stutter, still unclear why audio starts to stutter.
Without this cache bypass the flush TX/RX bits gets cached and flush happens unexpectedly resulting in multi channel audio getting mapped to wrong speaker. Other ASoC codecs and fsl_spdif.c seems to use similar cache bypass for reset/flush.
However, looking at the code, the write would seem to be ignored if the regmap is in the cache_only state. We only set this when the bus clock is disabled. Under such a condition, bypassing the cache and forcing a write would be unwise, as the system either drops the write, or stalls altogether.
/* Clear RX counter */ regmap_write(i2s->regmap, SUN4I_I2S_RX_CNT_REG, 0);@@ -569,9 +571,11 @@ static void sun4i_i2s_start_capture(struct sun4i_i2s *i2s) static void sun4i_i2s_start_playback(struct sun4i_i2s *i2s) { /* Flush TX FIFO */
regcache_cache_bypass(i2s->regmap, true); regmap_update_bits(i2s->regmap, SUN4I_I2S_FIFO_CTRL_REG, SUN4I_I2S_FIFO_CTRL_FLUSH_TX, SUN4I_I2S_FIFO_CTRL_FLUSH_TX);regcache_cache_bypass(i2s->regmap, false); /* Clear TX counter */ regmap_write(i2s->regmap, SUN4I_I2S_TX_CNT_REG, 0);@@ -703,13 +707,7 @@ static const struct snd_soc_component_driver sun4i_i2s_component = {
static bool sun4i_i2s_rd_reg(struct device *dev, unsigned int reg) {
switch (reg) {case SUN4I_I2S_FIFO_TX_REG:return false;default:return true;}
return true;I don't understand why this is relevant. Do you need to read back from the TX FIFO?
This change was inspired by c66234cfedfc "ASoC: rockchip: i2s: fix playback after runtime resume" [1] On resume a cached sample would be written to FIFO_TX_REG unless it is marked volatile, the rockchip commit indicated that read is needed for volatile regs.
[1] https://github.com/torvalds/linux/commit/c66234cfedfc3e6e3b62563a5f2c1562be0...
If so, just drop the call-back altogether. If no callback is provided and no rd_table is provided either, it defaults to all registers under max_register (if max_register < 0) are readable.
However this seems like it deserves to be a separate patch (where you explain in the commit log why it's needed).
Regards ChenYu
}
static bool sun4i_i2s_wr_reg(struct device *dev, unsigned int reg) @@ -728,6 +726,8 @@ static bool sun4i_i2s_volatile_reg(struct device *dev, unsigned int reg) { switch (reg) { case SUN4I_I2S_FIFO_RX_REG:
case SUN4I_I2S_FIFO_TX_REG:case SUN4I_I2S_FIFO_STA_REG: case SUN4I_I2S_INT_STA_REG: case SUN4I_I2S_RX_CNT_REG: case SUN4I_I2S_TX_CNT_REG:@@ -738,23 +738,12 @@ static bool sun4i_i2s_volatile_reg(struct device *dev, unsigned int reg) } }
-static bool sun8i_i2s_rd_reg(struct device *dev, unsigned int reg) -{
switch (reg) {case SUN8I_I2S_FIFO_TX_REG:return false;default:return true;}-}
static bool sun8i_i2s_volatile_reg(struct device *dev, unsigned int reg) { if (reg == SUN8I_I2S_INT_STA_REG) return true; if (reg == SUN8I_I2S_FIFO_TX_REG)
return false;
return true; return sun4i_i2s_volatile_reg(dev, reg);} @@ -809,7 +798,7 @@ static const struct regmap_config sun8i_i2s_regmap_config = { .reg_defaults = sun8i_i2s_reg_defaults, .num_reg_defaults = ARRAY_SIZE(sun8i_i2s_reg_defaults), .writeable_reg = sun4i_i2s_wr_reg,
.readable_reg = sun8i_i2s_rd_reg,
.readable_reg = sun4i_i2s_rd_reg, .volatile_reg = sun8i_i2s_volatile_reg,};
-- 2.20.1
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