[RFC 3/4] OMAP3: McBSP: Add interface for transmit FIFO state query

[Peter Ujfalusi <peter.ujfalusi@nokia.com>]

New function for reading the XBUFFSTAT register, which holds
the fill state of the transmit buffer on McBSP.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
---
 arch/arm/plat-omap/include/plat/mcbsp.h |    4 ++++
 arch/arm/plat-omap/mcbsp.c              |   27 +++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/arch/arm/plat-omap/include/plat/mcbsp.h b/arch/arm/plat-omap/include/plat/mcbsp.h
index 4f22e5b..98de3d4 100644
--- a/arch/arm/plat-omap/include/plat/mcbsp.h
+++ b/arch/arm/plat-omap/include/plat/mcbsp.h
@@ -147,6 +147,8 @@
 #define OMAP_MCBSP_REG_WAKEUPEN	0xA8
 #define OMAP_MCBSP_REG_XCCR	0xAC
 #define OMAP_MCBSP_REG_RCCR	0xB0
+#define OMAP_MCBSP_REG_XBUFFSTAT	0xB4
+#define OMAP_MCBSP_REG_RBUFFSTAT	0xB8
 
 #define AUDIO_MCBSP_DATAWRITE	(OMAP24XX_MCBSP2_BASE + OMAP_MCBSP_REG_DXR1)
 #define AUDIO_MCBSP_DATAREAD	(OMAP24XX_MCBSP2_BASE + OMAP_MCBSP_REG_DRR1)
@@ -428,6 +430,7 @@ void omap_mcbsp_set_tx_threshold(unsigned int id, u16 threshold);
 void omap_mcbsp_set_rx_threshold(unsigned int id, u16 threshold);
 u16 omap_mcbsp_get_max_tx_threshold(unsigned int id);
 u16 omap_mcbsp_get_max_rx_threshold(unsigned int id);
+u16 omap_mcbsp_get_tx_buffstat(unsigned int id);
 int omap_mcbsp_get_dma_op_mode(unsigned int id);
 #else
 static inline void omap_mcbsp_set_tx_threshold(unsigned int id, u16 threshold)
@@ -436,6 +439,7 @@ static inline void omap_mcbsp_set_rx_threshold(unsigned int id, u16 threshold)
 { }
 static inline u16 omap_mcbsp_get_max_tx_threshold(unsigned int id) { return 0; }
 static inline u16 omap_mcbsp_get_max_rx_threshold(unsigned int id) { return 0; }
+static inline u16 omap_mcbsp_get_tx_buffstat(unsigned int id) { return 0; }
 static inline int omap_mcbsp_get_dma_op_mode(unsigned int id) { return 0; }
 #endif
 int omap_mcbsp_request(unsigned int id);
diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c
index f757672..e49af86 100644
--- a/arch/arm/plat-omap/mcbsp.c
+++ b/arch/arm/plat-omap/mcbsp.c
@@ -284,6 +284,33 @@ u16 omap_mcbsp_get_max_rx_threshold(unsigned int id)
 EXPORT_SYMBOL(omap_mcbsp_get_max_rx_threshold);
 
 /*
+ * omap_mcbsp_get_tx_buffstat returns the number of used slots in the McBSP FIFO
+ */
+u16 omap_mcbsp_get_tx_buffstat(unsigned int id)
+{
+	struct omap_mcbsp *mcbsp;
+	u16 buffstat;
+
+	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);
+
+	/* Returns the number of free locations in the buffer */
+	buffstat = OMAP_MCBSP_READ(mcbsp->io_base, XBUFFSTAT);
+
+	/* Number of free slots on McBSP ports */
+	if (mcbsp->id == 2)
+		buffstat = 0x500 - buffstat;
+	else
+		buffstat = 0x80 - buffstat;
+
+	return buffstat;
+}
+EXPORT_SYMBOL(omap_mcbsp_get_tx_buffstat);
+
+/*
  * omap_mcbsp_get_dma_op_mode just return the current configured
  * operating mode for the mcbsp channel
  */
-- 
1.7.0