[Meego-kernel] [PATCH 1/2] spi/dw_spi: simplify the dma callback handling

[Feng Tang]

No functional change, just make the code simpler and cleaner.

Signed-off-by: Feng Tang <feng.tang at intel.com>
---
 drivers/spi/dw_spi_mid.c   |   33 ++++++++++-----------------------
 include/linux/spi/dw_spi.h |    5 +----
 2 files changed, 11 insertions(+), 27 deletions(-)

diff --git a/drivers/spi/dw_spi_mid.c b/drivers/spi/dw_spi_mid.c
index f7b5450..091e80b 100644
--- a/drivers/spi/dw_spi_mid.c
+++ b/drivers/spi/dw_spi_mid.c
@@ -100,13 +100,6 @@ static int mid_spi_dma_init(struct dw_spi *dws)
 
 	/* Set the dma done bit to 1 */
 	dws->dma_inited = 1;
-	dws->txdma_done = 1;
-	dws->rxdma_done = 1;
-
-	dws->tx_param = ((u64)(unsigned long)dws << 32)
-				| (unsigned long)(&dws->txdma_done);
-	dws->rx_param = ((u64)(unsigned long)dws << 32)
-				| (unsigned long)(&dws->rxdma_done);
 	return 0;
 
 free_rxchan:
@@ -122,20 +115,17 @@ static void mid_spi_dma_exit(struct dw_spi *dws)
 	dma_release_channel(dws->rxchan);
 }
 
+/*
+ * dws->dma_chan_done is cleared before the dma transfer starts,
+ * callback for rx/tx channel will each increment it by 1.
+ * Reaching 2 means the whole spi transaction is done.
+ */
 static void dw_spi_dma_done(void *arg)
 {
-	u64 *param = arg;
-	struct dw_spi *dws;
-	int *done;
+	struct dw_spi *dws = arg;
 
-	dws = (struct dw_spi *)(unsigned long)(*param >> 32);
-	done = (int *)(unsigned long)(*param & 0xffffffff);
-
-	*done = 1;
-	/* wait till both tx/rx channels are done */
-	if (!dws->txdma_done || !dws->rxdma_done)
+	if (++dws->dma_chan_done != 2)
 		return;
-
 	dw_spi_xfer_done(dws);
 }
 
@@ -159,10 +149,7 @@ static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change)
 		spi_enable_chip(dws, 1);
 	}
 
-	if (dws->tx_dma)
-		dws->txdma_done = 0;
-	if (dws->rx_dma)
-		dws->rxdma_done = 0;
+	dws->dma_chan_done = 0;
 
 	/* 2. start the TX dma transfer */
 	txchan = dws->txchan;
@@ -174,7 +161,7 @@ static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change)
 				dws->dma_addr, dws->tx_dma,
 				dws->len, flag);
 		txdesc->callback = dw_spi_dma_done;
-		txdesc->callback_param = &dws->tx_param;
+		txdesc->callback_param = dws;
 	}
 
 	/* 3. start the RX dma transfer */
@@ -183,7 +170,7 @@ static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change)
 				dws->rx_dma, dws->dma_addr,
 				dws->len, flag);
 		rxdesc->callback = dw_spi_dma_done;
-		rxdesc->callback_param = &dws->rx_param;
+		rxdesc->callback_param = dws;
 	}
 
 	/* rx must be started before tx due to spi instinct */
diff --git a/include/linux/spi/dw_spi.h b/include/linux/spi/dw_spi.h
index 0d20634..d9ce113 100644
--- a/include/linux/spi/dw_spi.h
+++ b/include/linux/spi/dw_spi.h
@@ -146,10 +146,7 @@ struct dw_spi {
 	int			dma_inited;
 	struct dma_chan		*txchan;
 	struct dma_chan		*rxchan;
-	int			txdma_done;
-	int			rxdma_done;
-	u64			tx_param;
-	u64			rx_param;
+	int			dma_chan_done;
 	struct device		*dma_dev;
 	dma_addr_t		dma_addr;
 	struct dw_spi_dma_ops	*dma_ops;
-- 
1.7.0.4