From: Carlos Song <[email protected]>
For DMA mode, the bus width of the DMA is equal to the size of data
word, so burst length should be configured as bits per word.
For CPU mode, because of the spi transfer len is in byte, so calculate
the total number of words according to spi transfer len and bits per
word, burst length should be configured as total data bits.
Signed-off-by: Carlos Song <[email protected]>
Reviewed-by: Clark Wang <[email protected]>
Fixes: e9b220aeacf1 ("spi: spi-imx: correctly configure burst length when using dma")
Fixes: 5f66db08cbd3 ("spi: imx: Take in account bits per word instead of assuming 8-bits")
---
Changes for V5:
- fix the the method of burst length calculation compatible with non-byte aligned wordsize.
---
drivers/spi/spi-imx.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 546cdce525fc..833a1bb7a914 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -2,6 +2,7 @@
// Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
// Copyright (C) 2008 Juergen Beisert
+#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
@@ -660,15 +661,15 @@ static int mx51_ecspi_prepare_transfer(struct spi_imx_data *spi_imx,
<< MX51_ECSPI_CTRL_BL_OFFSET;
else {
if (spi_imx->usedma) {
- ctrl |= (spi_imx->bits_per_word *
- spi_imx_bytes_per_word(spi_imx->bits_per_word) - 1)
+ ctrl |= (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)
+ ctrl |= (MX51_ECSPI_CTRL_MAX_BURST * BITS_PER_BYTE - 1)
<< MX51_ECSPI_CTRL_BL_OFFSET;
else
- ctrl |= (spi_imx->count * spi_imx->bits_per_word - 1)
+ ctrl |= spi_imx->count / DIV_ROUND_UP(spi_imx->bits_per_word,
+ BITS_PER_BYTE) * spi_imx->bits_per_word
<< MX51_ECSPI_CTRL_BL_OFFSET;
}
}
--
2.34.1
On Sun, 04 Feb 2024 17:19:12 +0800, [email protected] wrote:
> For DMA mode, the bus width of the DMA is equal to the size of data
> word, so burst length should be configured as bits per word.
>
> For CPU mode, because of the spi transfer len is in byte, so calculate
> the total number of words according to spi transfer len and bits per
> word, burst length should be configured as total data bits.
>
> [...]
Applied to
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next
Thanks!
[1/1] spi: imx: fix the burst length at DMA mode and CPU mode
commit: c712c05e46c8ce550842951e9e2606e24dbf0475
All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.
You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.
If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.
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Thanks,
Mark