diff options
| author | Jisheng Zhang <jszhang@kernel.org> | 2026-06-15 12:40:35 +0800 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2026-06-29 18:27:48 +0100 |
| commit | d322d820e0b0f16260e929de3f4e6b33b242c91c (patch) | |
| tree | 144934c926d79c2c558492a8f9a93a9513d031b4 | |
| parent | c1bab046d4786c5b17aab7c5225bf0d4a2a2d19b (diff) | |
spi: dw: fix first spi transfer with dma always fallback to PIO
Even with proper dma engine support, the first spi transfer always
fallback to PIO, the reason is the dws->n_bytes is 0 after
initialization, so the dw_spi_can_dma() calling from __spi_map_msg()
return false, thus both tx_sg_mapped and rx_sg_mapped are false, so
for the first spi transfer, the spi_xfer_is_dma_mapped() reports false
thus fallback to PIO.
Although this brings no harm, we can simply fix this issue by
calcuating the "n_bytes" from xfer->bits_per_word.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Link: https://patch.msgid.link/20260615044039.9750-2-jszhang@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
| -rw-r--r-- | drivers/spi/spi-dw-dma.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/spi/spi-dw-dma.c b/drivers/spi/spi-dw-dma.c index fe726b9b1780..bd70a7ed8067 100644 --- a/drivers/spi/spi-dw-dma.c +++ b/drivers/spi/spi-dw-dma.c @@ -247,11 +247,12 @@ static bool dw_spi_can_dma(struct spi_controller *ctlr, { struct dw_spi *dws = spi_controller_get_devdata(ctlr); enum dma_slave_buswidth dma_bus_width; + u8 n_bytes = roundup_pow_of_two(BITS_TO_BYTES(xfer->bits_per_word)); if (xfer->len <= dws->fifo_len) return false; - dma_bus_width = dw_spi_dma_convert_width(dws->n_bytes); + dma_bus_width = dw_spi_dma_convert_width(n_bytes); return dws->dma_addr_widths & BIT(dma_bus_width); } |