Use the actual FIFO size in words as buffer_size on OMAP3.
Change the threshold configuration to use 1 based numbering, when
specifying the allowed threshold maximum or the McBSP threshold value.
Set the default maximum threshold to (buffer_size - 0x10) intialy.
>From users of McBSP, now it is expected to use this method.
Asking for threshold 1 means that the value written to threshold registers
are going to be 0, which means 1 word threshold.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxxxxx>
Acked-by: Jarkko Nikula <jhnikula@xxxxxxxxx>
Acked-by: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
---
arch/arm/mach-omap2/mcbsp.c | 10 +++++-----
arch/arm/plat-omap/mcbsp.c | 30 ++++++++++++++++++++----------
2 files changed, 25 insertions(+), 15 deletions(-)
diff --git a/arch/arm/mach-omap2/mcbsp.c b/arch/arm/mach-omap2/mcbsp.c
index 016fe60..ed9f562 100644
--- a/arch/arm/mach-omap2/mcbsp.c
+++ b/arch/arm/mach-omap2/mcbsp.c
@@ -132,7 +132,7 @@ static struct omap_mcbsp_platform_data omap34xx_mcbsp_pdata[] = {
.rx_irq = INT_24XX_MCBSP1_IRQ_RX,
.tx_irq = INT_24XX_MCBSP1_IRQ_TX,
.ops = &omap2_mcbsp_ops,
- .buffer_size = 0x6F,
+ .buffer_size = 0x80, /* The FIFO has 128 locations */
},
{
.phys_base = OMAP34XX_MCBSP2_BASE,
@@ -142,7 +142,7 @@ static struct omap_mcbsp_platform_data omap34xx_mcbsp_pdata[] = {
.rx_irq = INT_24XX_MCBSP2_IRQ_RX,
.tx_irq = INT_24XX_MCBSP2_IRQ_TX,
.ops = &omap2_mcbsp_ops,
- .buffer_size = 0x3FF,
+ .buffer_size = 0x500, /* The FIFO has 1024 + 256 locations */
},
{
.phys_base = OMAP34XX_MCBSP3_BASE,
@@ -152,7 +152,7 @@ static struct omap_mcbsp_platform_data omap34xx_mcbsp_pdata[] = {
.rx_irq = INT_24XX_MCBSP3_IRQ_RX,
.tx_irq = INT_24XX_MCBSP3_IRQ_TX,
.ops = &omap2_mcbsp_ops,
- .buffer_size = 0x6F,
+ .buffer_size = 0x80, /* The FIFO has 128 locations */
},
{
.phys_base = OMAP34XX_MCBSP4_BASE,
@@ -161,7 +161,7 @@ static struct omap_mcbsp_platform_data omap34xx_mcbsp_pdata[] = {
.rx_irq = INT_24XX_MCBSP4_IRQ_RX,
.tx_irq = INT_24XX_MCBSP4_IRQ_TX,
.ops = &omap2_mcbsp_ops,
- .buffer_size = 0x6F,
+ .buffer_size = 0x80, /* The FIFO has 128 locations */
},
{
.phys_base = OMAP34XX_MCBSP5_BASE,
@@ -170,7 +170,7 @@ static struct omap_mcbsp_platform_data omap34xx_mcbsp_pdata[] = {
.rx_irq = INT_24XX_MCBSP5_IRQ_RX,
.tx_irq = INT_24XX_MCBSP5_IRQ_TX,
.ops = &omap2_mcbsp_ops,
- .buffer_size = 0x6F,
+ .buffer_size = 0x80, /* The FIFO has 128 locations */
},
};
#define OMAP34XX_MCBSP_PDATA_SZ ARRAY_SIZE(omap34xx_mcbsp_pdata)
diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c
index 51d8abf..d883bbf 100644
--- a/arch/arm/plat-omap/mcbsp.c
+++ b/arch/arm/plat-omap/mcbsp.c
@@ -480,9 +480,9 @@ int omap_st_is_enabled(unsigned int id)
EXPORT_SYMBOL(omap_st_is_enabled);
/*
- * omap_mcbsp_set_tx_threshold configures how to deal
- * with transmit threshold. the threshold value and handler can be
- * configure in here.
+ * omap_mcbsp_set_rx_threshold configures the transmit threshold in words.
+ * The threshold parameter is 1 based, and it is converted (threshold - 1)
+ * for the THRSH2 register.
*/
void omap_mcbsp_set_tx_threshold(unsigned int id, u16 threshold)
{
@@ -497,14 +497,15 @@ void omap_mcbsp_set_tx_threshold(unsigned int id, u16 threshold)
}
mcbsp = id_to_mcbsp_ptr(id);
- MCBSP_WRITE(mcbsp, THRSH2, threshold);
+ if (threshold && threshold <= mcbsp->max_tx_thres)
+ MCBSP_WRITE(mcbsp, THRSH2, threshold - 1);
}
EXPORT_SYMBOL(omap_mcbsp_set_tx_threshold);
/*
- * omap_mcbsp_set_rx_threshold configures how to deal
- * with receive threshold. the threshold value and handler can be
- * configure in here.
+ * omap_mcbsp_set_rx_threshold configures the receive threshold in words.
+ * The threshold parameter is 1 based, and it is converted (threshold - 1)
+ * for the THRSH1 register.
*/
void omap_mcbsp_set_rx_threshold(unsigned int id, u16 threshold)
{
@@ -519,7 +520,8 @@ void omap_mcbsp_set_rx_threshold(unsigned int id, u16 threshold)
}
mcbsp = id_to_mcbsp_ptr(id);
- MCBSP_WRITE(mcbsp, THRSH1, threshold);
+ if (threshold && threshold <= mcbsp->max_rx_thres)
+ MCBSP_WRITE(mcbsp, THRSH1, threshold - 1);
}
EXPORT_SYMBOL(omap_mcbsp_set_rx_threshold);
@@ -1696,8 +1698,16 @@ static inline void __devinit omap34xx_device_init(struct omap_mcbsp *mcbsp)
{
mcbsp->dma_op_mode = MCBSP_DMA_MODE_ELEMENT;
if (cpu_is_omap34xx()) {
- mcbsp->max_tx_thres = max_thres(mcbsp);
- mcbsp->max_rx_thres = max_thres(mcbsp);
+ /*
+ * Initially configure the maximum thresholds to a safe value.
+ * The McBSP FIFO usage with these values should not go under
+ * 16 locations.
+ * If the whole FIFO without safety buffer is used, than there
+ * is a possibility that the DMA will be not able to push the
+ * new data on time, causing channel shifts in runtime.
+ */
+ mcbsp->max_tx_thres = max_thres(mcbsp) - 0x10;
+ mcbsp->max_rx_thres = max_thres(mcbsp) - 0x10;
/*
* REVISIT: Set dmap_op_mode to THRESHOLD as default
* for mcbsp2 instances.
--
1.7.1
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