[v3] spi: imx: fix the burst length at DMA mode and CPU mode

[PATCH v3] 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 V3:
- include <linux/bits.h> 
---
 drivers/spi/spi-imx.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 546cdce525fc..2a1ae7b00760 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -21,7 +21,7 @@
 #include <linux/types.h>
 #include <linux/of.h>
 #include <linux/property.h>
-
+#include <linux/bits.h>
 #include <linux/dma/imx-dma.h>
 
 #define DRIVER_NAME "spi_imx"
@@ -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 v3] spi: imx: fix the burst length at DMA mode and CPU mode

Posted by Marc Kleine-Budde 1 year, 10 months ago

On 01.02.2024 18:01:15, 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 V3:
> - include <linux/bits.h> 
> ---
>  drivers/spi/spi-imx.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index 546cdce525fc..2a1ae7b00760 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -21,7 +21,7 @@
>  #include <linux/types.h>
>  #include <linux/of.h>
>  #include <linux/property.h>
> -
> +#include <linux/bits.h>

nitpick:
Please keep the includes sorted alphabetically.

>  #include <linux/dma/imx-dma.h>

Marc

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