[PATCH 06/14] spi: spi-fsl-dspi: Avoid setup_accel logic for DMA transfers

From: James Clark
Date: Fri May 09 2025 - 07:08:16 EST


From: Larisa Grigore <larisa.grigore@xxxxxxx>

DMA can't repack the buffer like the CPU can, so skip the accel path
which may change the word size and break DMA assumptions.

Signed-off-by: Larisa Grigore <larisa.grigore@xxxxxxx>
Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
---
drivers/spi/spi-fsl-dspi.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index f7f9425a19e1..902bf23d276a 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -849,8 +849,8 @@ static void dspi_setup_accel(struct fsl_dspi *dspi)
struct spi_transfer *xfer = dspi->cur_transfer;
bool odd = !!(dspi->len & 1);

- /* No accel for frames not multiple of 8 bits at the moment */
- if (xfer->bits_per_word % 8)
+ /* No accel for DMA transfers or frames not multiples of 8 bits at the moment */
+ if (dspi->devtype_data->trans_mode == DSPI_DMA_MODE || xfer->bits_per_word % 8)
goto no_accel;

if (!odd && dspi->len <= dspi->devtype_data->fifo_size * 2) {
@@ -859,10 +859,7 @@ static void dspi_setup_accel(struct fsl_dspi *dspi)
dspi->oper_bits_per_word = 8;
} else {
/* Start off with maximum supported by hardware */
- if (dspi->devtype_data->trans_mode == DSPI_XSPI_MODE)
- dspi->oper_bits_per_word = 32;
- else
- dspi->oper_bits_per_word = 16;
+ dspi->oper_bits_per_word = 32;

/*
* And go down only if the buffer can't be sent with

--
2.34.1