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spi: spi-imx: correctly configure burst length when using dma

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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@bigler.io>

Signed-off-by: Benjamin Bigler <benjamin@bigler.one>
Fixes: 15a6af94a277 ("spi: Increase imx51 ecspi burst length based on transfer length")
Link: https://lore.kernel.org/r/8a415902c751cdbb4b20ce76569216ed@mail.infomaniak.com
Link: https://lore.kernel.org/r/20231209222338.5564-1-benjamin@bigler.one
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Benjamin Bigler 2023-12-09 23:23:26 +01:00 committed by Mark Brown
parent 7a733e060b
commit e9b220aeac
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GPG Key ID: 24D68B725D5487D0
1 changed files with 11 additions and 4 deletions
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15
drivers/spi/spi-imx.c
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@ -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 */