1 files changed, 35 insertions, 16 deletions

diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c
index 7e669c9744d..e31496e35b0 100644
--- a/arch/arm/plat-omap/mcbsp.c
+++ b/arch/arm/plat-omap/mcbsp.c
@@ -481,9 +481,9 @@ 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)
 {
@@ -498,14 +498,15 @@ 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)
 {
@@ -520,7 +521,8 @@ 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);
 
@@ -560,8 +562,20 @@ u16 omap_mcbsp_get_max_rx_threshold(unsigned int id)
 }
 EXPORT_SYMBOL(omap_mcbsp_get_max_rx_threshold);
 
-#define MCBSP2_FIFO_SIZE	0x500 /* 1024 + 256 locations */
-#define MCBSP1345_FIFO_SIZE	0x80  /* 128 locations */
+u16 omap_mcbsp_get_fifo_size(unsigned int id)
+{
+	struct omap_mcbsp *mcbsp;
+
+	if (!omap_mcbsp_check_valid_id(id)) {
+		printk(KERN_ERR "%s: Invalid id (%d)\n", __func__, id + 1);
+		return -ENODEV;
+	}
+	mcbsp = id_to_mcbsp_ptr(id);
+
+	return mcbsp->pdata->buffer_size;
+}
+EXPORT_SYMBOL(omap_mcbsp_get_fifo_size);
+
 /*
  * omap_mcbsp_get_tx_delay returns the number of used slots in the McBSP FIFO
  */
@@ -580,10 +594,7 @@ u16 omap_mcbsp_get_tx_delay(unsigned int id)
 	buffstat = MCBSP_READ(mcbsp, XBUFFSTAT);
 
 	/* Number of slots are different in McBSP ports */
-	if (mcbsp->id == 2)
-		return MCBSP2_FIFO_SIZE - buffstat;
-	else
-		return MCBSP1345_FIFO_SIZE - buffstat;
+	return mcbsp->pdata->buffer_size - buffstat;
 }
 EXPORT_SYMBOL(omap_mcbsp_get_tx_delay);
 
@@ -1683,8 +1694,16 @@ 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.