6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Benjamin Bigler <benjamin@xxxxxxxxxx>
[ Upstream commit e9b220aeacf109684cce36a94fc24ed37be92b05 ]
If DMA is used, burst length should be set to the bus width of the DMA.
Otherwise, the SPI hardware will transmit/receive one word per DMA
request.
Since this issue affects both transmission and reception, it cannot be
detected with a loopback test.
Replace magic numbers 512 and 0xfff with MX51_ECSPI_CTRL_MAX_BURST.
Reported-by Stefan Bigler <linux@xxxxxxxxx>
Signed-off-by: Benjamin Bigler <benjamin@xxxxxxxxxx>
Fixes: 15a6af94a277 ("spi: Increase imx51 ecspi burst length based on transfer length")
Link: https://lore.kernel.org/r/8a415902c751cdbb4b20ce76569216ed@xxxxxxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20231209222338.5564-1-benjamin@xxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/spi/spi-imx.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 498e35c8db2c1..272bc871a848b 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -659,11 +659,18 @@ static int mx51_ecspi_prepare_transfer(struct spi_imx_data *spi_imx,
ctrl |= (spi_imx->target_burst * 8 - 1)
<< MX51_ECSPI_CTRL_BL_OFFSET;
else {
- if (spi_imx->count >= 512)
- ctrl |= 0xFFF << MX51_ECSPI_CTRL_BL_OFFSET;
- else
- ctrl |= (spi_imx->count * spi_imx->bits_per_word - 1)
+ if (spi_imx->usedma) {
+ ctrl |= (spi_imx->bits_per_word *
+ spi_imx_bytes_per_word(spi_imx->bits_per_word) - 1)
<< MX51_ECSPI_CTRL_BL_OFFSET;
+ } else {
+ if (spi_imx->count >= MX51_ECSPI_CTRL_MAX_BURST)
+ ctrl |= (MX51_ECSPI_CTRL_MAX_BURST - 1)
+ << MX51_ECSPI_CTRL_BL_OFFSET;
+ else
+ ctrl |= (spi_imx->count * spi_imx->bits_per_word - 1)
+ << MX51_ECSPI_CTRL_BL_OFFSET;
+ }
}
/* set clock speed */
--
2.43.0
