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| author | Jiada Wang <jiada_wang@mentor.com> | 2017-01-06 04:22:18 -0800 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2017-01-06 18:09:22 +0000 |
| commit | 66459c5a50a787c474b734b586328f7111ab6df0 (patch) | |
| tree | 88df0f0674456138bfc9842585e371ee8b82fe82 /drivers/spi | |
| parent | fafd67940774733fa97f4b09412aea6981b82e0a (diff) | |
| download | linux-66459c5a50a787c474b734b586328f7111ab6df0.tar.gz linux-66459c5a50a787c474b734b586328f7111ab6df0.tar.bz2 linux-66459c5a50a787c474b734b586328f7111ab6df0.zip | |
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 <jiada_wang@mentor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-imx.c | 16 |
1 files changed, 8 insertions, 8 deletions
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; |