[PATCH] spi: imx: keep dma request disabled before dma transfer setup

[PATCH] spi: imx: keep dma request disabled before dma transfer setup

[carlos.song]

From: Robin Gong <yibin.gong@nxp.com>

Since sdma hardware configure postpone to transfer phase, have to disable
dma request before dma transfer setup because there is a hardware
limitation on sdma event enable(ENBLn) as below:

"It is thus essential for the Arm platform to program them before any DMA
 request is triggered to the SDMA, otherwise an unpredictable combination
 of channels may be started."

Signed-off-by: Carlos Song <carlos.song@nxp.com>
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
---
 drivers/spi/spi-imx.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index cd40db61d8d1..765ea507dd8d 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -529,9 +529,15 @@ static void mx51_ecspi_trigger(struct spi_imx_data *spi_imx)
 {
 	u32 reg;
 
-	reg = readl(spi_imx->base + MX51_ECSPI_CTRL);
-	reg |= MX51_ECSPI_CTRL_XCH;
-	writel(reg, spi_imx->base + MX51_ECSPI_CTRL);
+	if (spi_imx->usedma) {
+		reg = readl(spi_imx->base + MX51_ECSPI_DMA);
+		reg |= MX51_ECSPI_DMA_TEDEN | MX51_ECSPI_DMA_RXDEN;
+		writel(reg, spi_imx->base + MX51_ECSPI_DMA);
+	} else {
+		reg = readl(spi_imx->base + MX51_ECSPI_CTRL);
+		reg |= MX51_ECSPI_CTRL_XCH;
+		writel(reg, spi_imx->base + MX51_ECSPI_CTRL);
+	}
 }
 
 static void mx51_ecspi_disable(struct spi_imx_data *spi_imx)
@@ -772,7 +778,6 @@ static void mx51_setup_wml(struct spi_imx_data *spi_imx)
 	writel(MX51_ECSPI_DMA_RX_WML(spi_imx->wml - 1) |
 		MX51_ECSPI_DMA_TX_WML(tx_wml) |
 		MX51_ECSPI_DMA_RXT_WML(spi_imx->wml) |
-		MX51_ECSPI_DMA_TEDEN | MX51_ECSPI_DMA_RXDEN |
 		MX51_ECSPI_DMA_RXTDEN, spi_imx->base + MX51_ECSPI_DMA);
 }
 
@@ -1539,6 +1544,8 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
 	reinit_completion(&spi_imx->dma_tx_completion);
 	dma_async_issue_pending(controller->dma_tx);
 
+	spi_imx->devtype_data->trigger(spi_imx);
+
 	transfer_timeout = spi_imx_calculate_timeout(spi_imx, transfer->len);
 
 	/* Wait SDMA to finish the data transfer.*/
-- 
2.34.1

Re: [PATCH] spi: imx: keep dma request disabled before dma transfer setup

[Frank Li]

On Fri, Oct 24, 2025 at 01:53:20PM +0800, carlos.song@nxp.com wrote:
> From: Robin Gong <yibin.gong@nxp.com>
>
> Since sdma hardware configure postpone to transfer phase, have to disable
> dma request before dma transfer setup because there is a hardware
> limitation on sdma event enable(ENBLn) as below:

Due to a hardware limitation on SDMA event enable (ENBLn), the DMA request
must remain disabled until the DMA transfer setup is complete.

Ref spec section [...]
>
> "It is thus essential for the Arm platform to program them before any DMA
>  request is triggered to the SDMA, otherwise an unpredictable combination
>  of channels may be started."

SDMA hardware configuration is postponed to the transfer phase, so enabling
the DMA request too early may cause unpredictable channel activation. Then
keep dma request disabled before dma transfer setup.

Frank
>
> Signed-off-by: Carlos Song <carlos.song@nxp.com>
> Signed-off-by: Robin Gong <yibin.gong@nxp.com>
> ---
>  drivers/spi/spi-imx.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index cd40db61d8d1..765ea507dd8d 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -529,9 +529,15 @@ static void mx51_ecspi_trigger(struct spi_imx_data *spi_imx)
>  {
>  	u32 reg;
>
> -	reg = readl(spi_imx->base + MX51_ECSPI_CTRL);
> -	reg |= MX51_ECSPI_CTRL_XCH;
> -	writel(reg, spi_imx->base + MX51_ECSPI_CTRL);
> +	if (spi_imx->usedma) {
> +		reg = readl(spi_imx->base + MX51_ECSPI_DMA);
> +		reg |= MX51_ECSPI_DMA_TEDEN | MX51_ECSPI_DMA_RXDEN;
> +		writel(reg, spi_imx->base + MX51_ECSPI_DMA);
> +	} else {
> +		reg = readl(spi_imx->base + MX51_ECSPI_CTRL);
> +		reg |= MX51_ECSPI_CTRL_XCH;
> +		writel(reg, spi_imx->base + MX51_ECSPI_CTRL);
> +	}
>  }
>
>  static void mx51_ecspi_disable(struct spi_imx_data *spi_imx)
> @@ -772,7 +778,6 @@ static void mx51_setup_wml(struct spi_imx_data *spi_imx)
>  	writel(MX51_ECSPI_DMA_RX_WML(spi_imx->wml - 1) |
>  		MX51_ECSPI_DMA_TX_WML(tx_wml) |
>  		MX51_ECSPI_DMA_RXT_WML(spi_imx->wml) |
> -		MX51_ECSPI_DMA_TEDEN | MX51_ECSPI_DMA_RXDEN |
>  		MX51_ECSPI_DMA_RXTDEN, spi_imx->base + MX51_ECSPI_DMA);
>  }
>
> @@ -1539,6 +1544,8 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
>  	reinit_completion(&spi_imx->dma_tx_completion);
>  	dma_async_issue_pending(controller->dma_tx);
>
> +	spi_imx->devtype_data->trigger(spi_imx);
> +
>  	transfer_timeout = spi_imx_calculate_timeout(spi_imx, transfer->len);
>
>  	/* Wait SDMA to finish the data transfer.*/
> --
> 2.34.1
>

Re: [PATCH] spi: imx: keep dma request disabled before dma transfer setup

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 406 bytes --]

On Fri, Oct 24, 2025 at 01:53:20PM +0800, carlos.song@nxp.com wrote:

> From: Robin Gong <yibin.gong@nxp.com>

...

> Signed-off-by: Carlos Song <carlos.song@nxp.com>
> Signed-off-by: Robin Gong <yibin.gong@nxp.com>

If you're sending a patch your signoff should go last in the chain, here
it looks like you're forwarding something Robin wrote so his signoff
should be first then you add yours after that.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH] spi: imx: keep dma request disabled before dma transfer setup

[Mark Brown]

On Fri, 24 Oct 2025 13:53:20 +0800, carlos.song@nxp.com wrote:
> Since sdma hardware configure postpone to transfer phase, have to disable
> dma request before dma transfer setup because there is a hardware
> limitation on sdma event enable(ENBLn) as below:
> 
> "It is thus essential for the Arm platform to program them before any DMA
>  request is triggered to the SDMA, otherwise an unpredictable combination
>  of channels may be started."
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/1] spi: imx: keep dma request disabled before dma transfer setup
      commit: 86d57d9c07d54e8cb385ffe800930816ccdba0c1

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.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark