[v2] spi: imx: fix the burst length at DMA mode and CPU mode

[PATCH v2] spi: imx: fix the burst length at DMA mode and CPU mode

Posted by carlos.song@nxp.com 1 year, 10 months ago

From: Carlos Song <carlos.song@nxp.com>

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 burst
length should be configured as bits per byte * spi_imx->count.

Signed-off-by: Carlos Song <carlos.song@nxp.com>
Reviewed-by: Clark Wang <xiaoning.wang@nxp.com>
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 V2:
- Removed BITS_PER_BYTE defination
---
 drivers/spi/spi-imx.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 546cdce525fc..0436e7a161ef 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -660,15 +660,14 @@ 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 * BITS_PER_BYTE - 1)
 						<< MX51_ECSPI_CTRL_BL_OFFSET;
 		}
 	}
-- 
2.34.1

Re: [PATCH v2] spi: imx: fix the burst length at DMA mode and CPU mode

Posted by Francesco Dolcini 1 year, 10 months ago

On Wed, Jan 31, 2024 at 06:19:16PM +0800, carlos.song@nxp.com wrote:
> From: Carlos Song <carlos.song@nxp.com>
> 
> 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 burst
> length should be configured as bits per byte * spi_imx->count.
> 
> Signed-off-by: Carlos Song <carlos.song@nxp.com>
> Reviewed-by: Clark Wang <xiaoning.wang@nxp.com>
> 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 V2:
> - Removed BITS_PER_BYTE defination
> ---
>  drivers/spi/spi-imx.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index 546cdce525fc..0436e7a161ef 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -660,15 +660,14 @@ 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 * BITS_PER_BYTE - 1)
>  						<< MX51_ECSPI_CTRL_BL_OFFSET;
>  		}
>  	}

Add #include <linux/bits.h> given you are using BITS_PER_BYTE

Francesco