On 19/08/2019 17.38, Marc Kleine-Budde wrote:
There is no need to duplicate what SPI core already does, i.e. mapping buffers
for DMA capable transfers. This patch removes all related pices of code.
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Tested-by: Sean Nyekjaer <sean@xxxxxxxxxx>
---
drivers/net/can/spi/mcp251x.c | 58 ++++++-----------------------------
1 file changed, 10 insertions(+), 48 deletions(-)
diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index 0cdb88a9525f..78d44801a0b5 100644
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -47,7 +47,6 @@
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/device.h>
-#include <linux/dma-mapping.h>
#include <linux/freezer.h>
#include <linux/interrupt.h>
#include <linux/io.h>
@@ -202,10 +201,6 @@
#define DEVICE_NAME "mcp251x"
-static int mcp251x_enable_dma; /* Enable SPI DMA. Default: 0 (Off) */
-module_param(mcp251x_enable_dma, int, 0444);
-MODULE_PARM_DESC(mcp251x_enable_dma, "Enable SPI DMA. Default: 0 (Off)");
-
static const struct can_bittiming_const mcp251x_bittiming_const = {
.name = DEVICE_NAME,
.tseg1_min = 3,
@@ -234,8 +229,6 @@ struct mcp251x_priv {
u8 *spi_tx_buf;
u8 *spi_rx_buf;
- dma_addr_t spi_tx_dma;
- dma_addr_t spi_rx_dma;
struct sk_buff *tx_skb;
int tx_len;
@@ -304,13 +297,6 @@ static int mcp251x_spi_trans(struct spi_device *spi, int len)
int ret;
spi_message_init(&m);
-
- if (mcp251x_enable_dma) {
- t.tx_dma = priv->spi_tx_dma;
- t.rx_dma = priv->spi_rx_dma;
- m.is_dma_mapped = 1;
- }
-
spi_message_add_tail(&t, &m);
ret = spi_sync(spi, &m);
@@ -1101,42 +1087,18 @@ static int mcp251x_can_probe(struct spi_device *spi)
priv->spi = spi;
mutex_init(&priv->mcp_lock);
- /* If requested, allocate DMA buffers */
- if (mcp251x_enable_dma) {
- spi->dev.coherent_dma_mask = ~0;
-
- /* Minimum coherent DMA allocation is PAGE_SIZE, so allocate
- * that much and share it between Tx and Rx DMA buffers.
- */
- priv->spi_tx_buf = dmam_alloc_coherent(&spi->dev,
- PAGE_SIZE,
- &priv->spi_tx_dma,
- GFP_DMA);
-
- if (priv->spi_tx_buf) {
- priv->spi_rx_buf = (priv->spi_tx_buf + (PAGE_SIZE / 2));
- priv->spi_rx_dma = (dma_addr_t)(priv->spi_tx_dma +
- (PAGE_SIZE / 2));
- } else {
- /* Fall back to non-DMA */
- mcp251x_enable_dma = 0;
- }
+ priv->spi_tx_buf = devm_kzalloc(&spi->dev, SPI_TRANSFER_BUF_LEN,
+ GFP_KERNEL);
+ if (!priv->spi_tx_buf) {
+ ret = -ENOMEM;
+ goto error_probe;
}
- /* Allocate non-DMA buffers */
- if (!mcp251x_enable_dma) {
- priv->spi_tx_buf = devm_kzalloc(&spi->dev, SPI_TRANSFER_BUF_LEN,
- GFP_KERNEL);
- if (!priv->spi_tx_buf) {
- ret = -ENOMEM;
- goto error_probe;
- }
- priv->spi_rx_buf = devm_kzalloc(&spi->dev, SPI_TRANSFER_BUF_LEN,
- GFP_KERNEL);
- if (!priv->spi_rx_buf) {
- ret = -ENOMEM;
- goto error_probe;
- }
+ priv->spi_rx_buf = devm_kzalloc(&spi->dev, SPI_TRANSFER_BUF_LEN,
+ GFP_KERNEL);
+ if (!priv->spi_rx_buf) {
+ ret = -ENOMEM;
+ goto error_probe;
}
SET_NETDEV_DEV(net, &spi->dev);
