From 66459c5a50a787c474b734b586328f7111ab6df0 Mon Sep 17 00:00:00 2001 From: Jiada Wang Date: Fri, 6 Jan 2017 04:22:18 -0800 Subject: spi: imx: adjust watermark level according to transfer length 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 Signed-off-by: Mark Brown --- drivers/spi/spi-imx.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'drivers') diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index 32ced64a5bb9..9a7c62f471dc 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -211,7 +211,7 @@ 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; @@ -228,12 +228,16 @@ 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; } @@ -837,10 +841,6 @@ 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; -- cgit v1.2.3