[PATCH 3.17 024/146] spi/rockchip: fix bug that cause the failure to read data in DMA mode

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



3.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Addy Ke <addy.ke@xxxxxxxxxxxxxx>

commit a24e70c0ac146f8bcae3cdb7f514950d5b32219e upstream.

In my test on RK3288-pinky board, if spi is enabled, it will begin to
read data from slave regardless of whether the DMA is ready. So we
need prepare DMA before spi is enable.

Signed-off-by: Addy Ke <addy.ke@xxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/spi/spi-rockchip.c |   15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -415,7 +415,7 @@ static void rockchip_spi_dma_txcb(void *
 	spin_unlock_irqrestore(&rs->lock, flags);
 }
 
-static int rockchip_spi_dma_transfer(struct rockchip_spi *rs)
+static void rockchip_spi_prepare_dma(struct rockchip_spi *rs)
 {
 	unsigned long flags;
 	struct dma_slave_config rxconf, txconf;
@@ -474,8 +474,6 @@ static int rockchip_spi_dma_transfer(str
 		dmaengine_submit(txdesc);
 		dma_async_issue_pending(rs->dma_tx.ch);
 	}
-
-	return 1;
 }
 
 static void rockchip_spi_config(struct rockchip_spi *rs)
@@ -557,16 +555,17 @@ static int rockchip_spi_transfer_one(
 	else if (rs->rx)
 		rs->tmode = CR0_XFM_RO;
 
-	if (master->can_dma && master->can_dma(master, spi, xfer))
+	/* we need prepare dma before spi was enabled */
+	if (master->can_dma && master->can_dma(master, spi, xfer)) {
 		rs->use_dma = 1;
-	else
+		rockchip_spi_prepare_dma(rs);
+	} else {
 		rs->use_dma = 0;
+	}
 
 	rockchip_spi_config(rs);
 
-	if (rs->use_dma)
-		ret = rockchip_spi_dma_transfer(rs);
-	else
+	if (!rs->use_dma)
 		ret = rockchip_spi_pio_transfer(rs);
 
 	return ret;


--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]