From: Jiada Wang jiada_wang@mentor.com
[ Upstream commit 66459c5a50a787c474b734b586328f7111ab6df0 ]
Previously DMA watermark level is configured to fifosize/2, DMA mode can be used only when transfer length can be divided by 'watermark level * bpw', which makes DMA mode not pratical.
This patch adjusts watermark level to largest number (no bigger than fifosize/2) which can divide 'tranfer length / bpw' for each transfer.
Signed-off-by: Jiada Wang jiada_wang@mentor.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin alexander.levin@verizon.com --- drivers/spi/spi-imx.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index deb782f6556c..84a2b152be55 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -210,7 +210,7 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi, struct spi_transfer *transfer) { struct spi_imx_data *spi_imx = spi_master_get_devdata(master); - unsigned int bpw; + unsigned int bpw, i;
if (!master->dma_rx) return false; @@ -227,12 +227,16 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi, if (bpw != 1 && bpw != 2 && bpw != 4) return false;
- if (transfer->len < spi_imx->wml * bpw) - return false; + for (i = spi_imx_get_fifosize(spi_imx) / 2; i > 0; i--) { + if (!(transfer->len % (i * bpw))) + break; + }
- if (transfer->len % (spi_imx->wml * bpw)) + if (i == 0) return false;
+ spi_imx->wml = i; + return true; }
@@ -818,10 +822,6 @@ static int spi_imx_dma_configure(struct spi_master *master, struct dma_slave_config rx = {}, tx = {}; struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
- if (bytes_per_word == spi_imx->bytes_per_word) - /* Same as last time */ - return 0; - switch (bytes_per_word) { case 4: buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;