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i2c: sh_mobile: use core helper to decide when to use DMA

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This ensures that we fall back to PIO if the message length is too small
for DMA being useful. Otherwise, we use DMA. A bounce buffer might be
applied by the helper if the original message buffer is not DMA safe.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Wolfram Sang 2017-11-04 21:20:08 +01:00 committed by Wolfram Sang
parent d4e01186ae
commit fe23aa9a16
1 changed files with 6 additions and 2 deletions
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8
drivers/i2c/busses/i2c-sh_mobile.c
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@ -144,6 +144,7 @@ struct sh_mobile_i2c_data {
struct dma_chan *dma_rx;
struct scatterlist sg;
enum dma_data_direction dma_direction;
u8 *dma_buf;
};
struct sh_mobile_dt_config {
@ -501,6 +502,8 @@ static void sh_mobile_i2c_dma_callback(void *data)
pd->pos = pd->msg->len;
pd->stop_after_dma = true;
i2c_release_dma_safe_msg_buf(pd->msg, pd->dma_buf);
iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE);
}
@ -561,7 +564,7 @@ static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
if (IS_ERR(chan))
return;
dma_addr = dma_map_single(chan->device->dev, pd->msg->buf, pd->msg->len, dir);
dma_addr = dma_map_single(chan->device->dev, pd->dma_buf, pd->msg->len, dir);
if (dma_mapping_error(chan->device->dev, dma_addr)) {
dev_dbg(pd->dev, "dma map failed, using PIO\n");
return;
@ -618,7 +621,8 @@ static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
pd->pos = -1;
pd->sr = 0;
if (pd->msg->len > 8)
pd->dma_buf = i2c_get_dma_safe_msg_buf(pd->msg, 8);
if (pd->dma_buf)
sh_mobile_i2c_xfer_dma(pd);
/* Enable all interrupts to begin with */