diff options
| author | Wolfram Sang <wsa+renesas@sang-engineering.com> | 2017-11-04 21:20:08 +0100 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2017-12-03 21:24:59 +0100 |
| commit | fe23aa9a1670b8800b251fc0400425e765c81880 (patch) | |
| tree | e68be308be2431de60051bfcfdc09ae82983ea39 /drivers/i2c/busses/i2c-sh_mobile.c | |
| parent | i2c: add docs to clarify DMA handling (diff) | |
| download | linux-fe23aa9a1670b8800b251fc0400425e765c81880.tar.xz linux-fe23aa9a1670b8800b251fc0400425e765c81880.zip | |
i2c: sh_mobile: use core helper to decide when to use DMA
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>
Diffstat (limited to 'drivers/i2c/busses/i2c-sh_mobile.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-sh_mobile.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c index bc1605a31534..b01607b4fce2 100644 --- a/drivers/i2c/busses/i2c-sh_mobile.c +++ b/drivers/i2c/busses/i2c-sh_mobile.c @@ -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 */ |