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authorJarkko Nikula <jhnikula@gmail.com>2009-08-07 10:59:47 +0400
committerMark Brown <broonie@opensource.wolfsonmicro.com>2009-08-07 13:57:42 +0400
commitc12abc012e18b362204345c323536f228d65c4db (patch)
tree105552bd558076eb3206ce5f4026af60921dc27f /arch
parent06c71282a90470184a78f7f0ab0f7ce0fc1f69c8 (diff)
downloadlinux-c12abc012e18b362204345c323536f228d65c4db.tar.xz
ARM: OMAP: McBSP: Fix ASoC on OMAP1510 by fixing API of omap_mcbsp_start/stop
Simultaneous audio playback and capture on OMAP1510 can cause that second stream is stalled if there is enough delay between startup of the audio streams. Current implementation of the omap_mcbsp_start is starting both transmitter and receiver at the same time and it is called only for firstly started audio stream from the OMAP McBSP based ASoC DAI driver. Since DMA request lines on OMAP1510 are edge sensitive, the DMA request is missed if there is no DMA transfer set up at that time when the first word after McBSP startup is transmitted. The problem hasn't noted before since later OMAPs are using level sensitive DMA request lines. Fix the problem by changing API of omap_mcbsp_start and omap_mcbsp_stop by allowing to start and stop individually McBSP transmitter and receiver logics. Then call those functions individually for both audio playback and capture streams. This ensures that DMA transfer is setup before transmitter or receiver is started. Thanks to Janusz Krzysztofik <jkrzyszt@tis.icnet.pl> for detailed problem analysis and Peter Ujfalusi <peter.ujfalusi@nokia.com> for info about DMA request line behavior differences between the OMAP generations. Reported-and-tested-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl> Signed-off-by: Jarkko Nikula <jhnikula@gmail.com> Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Peter Ujfalusi <peter.ujfalusi@nokia.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/plat-omap/include/mach/mcbsp.h4
-rw-r--r--arch/arm/plat-omap/mcbsp.c50
2 files changed, 34 insertions, 20 deletions
diff --git a/arch/arm/plat-omap/include/mach/mcbsp.h b/arch/arm/plat-omap/include/mach/mcbsp.h
index bb154ea76769..57249bb1e9bc 100644
--- a/arch/arm/plat-omap/include/mach/mcbsp.h
+++ b/arch/arm/plat-omap/include/mach/mcbsp.h
@@ -387,8 +387,8 @@ void omap_mcbsp_register_board_cfg(struct omap_mcbsp_platform_data *config,
void omap_mcbsp_config(unsigned int id, const struct omap_mcbsp_reg_cfg * config);
int omap_mcbsp_request(unsigned int id);
void omap_mcbsp_free(unsigned int id);
-void omap_mcbsp_start(unsigned int id);
-void omap_mcbsp_stop(unsigned int id);
+void omap_mcbsp_start(unsigned int id, int tx, int rx);
+void omap_mcbsp_stop(unsigned int id, int tx, int rx);
void omap_mcbsp_xmit_word(unsigned int id, u32 word);
u32 omap_mcbsp_recv_word(unsigned int id);
diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c
index efa0e0111f38..a3d2313460b3 100644
--- a/arch/arm/plat-omap/mcbsp.c
+++ b/arch/arm/plat-omap/mcbsp.c
@@ -328,14 +328,15 @@ void omap_mcbsp_free(unsigned int id)
EXPORT_SYMBOL(omap_mcbsp_free);
/*
- * Here we start the McBSP, by enabling the sample
- * generator, both transmitter and receivers,
- * and the frame sync.
+ * Here we start the McBSP, by enabling transmitter, receiver or both.
+ * If no transmitter or receiver is active prior calling, then sample-rate
+ * generator and frame sync are started.
*/
-void omap_mcbsp_start(unsigned int id)
+void omap_mcbsp_start(unsigned int id, int tx, int rx)
{
struct omap_mcbsp *mcbsp;
void __iomem *io_base;
+ int idle;
u16 w;
if (!omap_mcbsp_check_valid_id(id)) {
@@ -348,32 +349,40 @@ void omap_mcbsp_start(unsigned int id)
mcbsp->rx_word_length = (OMAP_MCBSP_READ(io_base, RCR1) >> 5) & 0x7;
mcbsp->tx_word_length = (OMAP_MCBSP_READ(io_base, XCR1) >> 5) & 0x7;
- /* Start the sample generator */
- w = OMAP_MCBSP_READ(io_base, SPCR2);
- OMAP_MCBSP_WRITE(io_base, SPCR2, w | (1 << 6));
+ idle = !((OMAP_MCBSP_READ(io_base, SPCR2) |
+ OMAP_MCBSP_READ(io_base, SPCR1)) & 1);
+
+ if (idle) {
+ /* Start the sample generator */
+ w = OMAP_MCBSP_READ(io_base, SPCR2);
+ OMAP_MCBSP_WRITE(io_base, SPCR2, w | (1 << 6));
+ }
/* Enable transmitter and receiver */
w = OMAP_MCBSP_READ(io_base, SPCR2);
- OMAP_MCBSP_WRITE(io_base, SPCR2, w | 1);
+ OMAP_MCBSP_WRITE(io_base, SPCR2, w | (tx & 1));
w = OMAP_MCBSP_READ(io_base, SPCR1);
- OMAP_MCBSP_WRITE(io_base, SPCR1, w | 1);
+ OMAP_MCBSP_WRITE(io_base, SPCR1, w | (rx & 1));
udelay(100);
- /* Start frame sync */
- w = OMAP_MCBSP_READ(io_base, SPCR2);
- OMAP_MCBSP_WRITE(io_base, SPCR2, w | (1 << 7));
+ if (idle) {
+ /* Start frame sync */
+ w = OMAP_MCBSP_READ(io_base, SPCR2);
+ OMAP_MCBSP_WRITE(io_base, SPCR2, w | (1 << 7));
+ }
/* Dump McBSP Regs */
omap_mcbsp_dump_reg(id);
}
EXPORT_SYMBOL(omap_mcbsp_start);
-void omap_mcbsp_stop(unsigned int id)
+void omap_mcbsp_stop(unsigned int id, int tx, int rx)
{
struct omap_mcbsp *mcbsp;
void __iomem *io_base;
+ int idle;
u16 w;
if (!omap_mcbsp_check_valid_id(id)) {
@@ -386,15 +395,20 @@ void omap_mcbsp_stop(unsigned int id)
/* Reset transmitter */
w = OMAP_MCBSP_READ(io_base, SPCR2);
- OMAP_MCBSP_WRITE(io_base, SPCR2, w & ~(1));
+ OMAP_MCBSP_WRITE(io_base, SPCR2, w & ~(tx & 1));
/* Reset receiver */
w = OMAP_MCBSP_READ(io_base, SPCR1);
- OMAP_MCBSP_WRITE(io_base, SPCR1, w & ~(1));
+ OMAP_MCBSP_WRITE(io_base, SPCR1, w & ~(rx & 1));
- /* Reset the sample rate generator */
- w = OMAP_MCBSP_READ(io_base, SPCR2);
- OMAP_MCBSP_WRITE(io_base, SPCR2, w & ~(1 << 6));
+ idle = !((OMAP_MCBSP_READ(io_base, SPCR2) |
+ OMAP_MCBSP_READ(io_base, SPCR1)) & 1);
+
+ if (idle) {
+ /* Reset the sample rate generator */
+ w = OMAP_MCBSP_READ(io_base, SPCR2);
+ OMAP_MCBSP_WRITE(io_base, SPCR2, w & ~(1 << 6));
+ }
}
EXPORT_SYMBOL(omap_mcbsp_stop);