can: grcan: Enhance driver with CANFD Support and Improvements

[PATCH 07/10] can: grcan: set DMA mask for GRCAN and GRCANFD to 32-bit

Posted by Arun Muthusamy 1 week, 6 days ago

From: Daniel Hellstrom <daniel@gaisler.com>

Sets the DMA mask for GRCAN and GRCANFD devices to 32-bit.
Setting the DMA mask and coherent DMA mask to 32-bit ensures proper
memory addressing during DMA operations

Signed-off-by: Arun Muthusamy <arun.muthusamy@gaisler.com>
Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
---
 drivers/net/can/grcan.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c
index e367581faa57..51a10fae2faf 100644
--- a/drivers/net/can/grcan.c
+++ b/drivers/net/can/grcan.c
@@ -1074,6 +1074,12 @@ static int grcan_allocate_dma_buffers(struct net_device *dev,

 	/* Extra GRCAN_BUFFER_ALIGNMENT to allow for alignment */
 	dma->base_size = lsize + ssize + GRCAN_BUFFER_ALIGNMENT;
+
+	/* On 64-bit systems.. GRCAN and GRCANFD can only address 32-bit */
+	if (dma_set_mask_and_coherent(priv->ofdev_dev, DMA_BIT_MASK(32))) {
+		netdev_warn(dev, "No suitable DMA available\n");
+		return -ENOMEM;
+	}
 	dma->base_buf = dma_alloc_coherent(priv->ofdev_dev,
 					   dma->base_size,
 					   &dma->base_handle,
--
2.51.0

Re: [PATCH 07/10] can: grcan: set DMA mask for GRCAN and GRCANFD to 32-bit

Posted by Marc Kleine-Budde 1 week, 3 days ago

On 18.11.2025 10:21:12, Arun Muthusamy wrote:
> From: Daniel Hellstrom <daniel@gaisler.com>
>
> Sets the DMA mask for GRCAN and GRCANFD devices to 32-bit.
> Setting the DMA mask and coherent DMA mask to 32-bit ensures proper
> memory addressing during DMA operations
>
> Signed-off-by: Arun Muthusamy <arun.muthusamy@gaisler.com>
> Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
> ---
>  drivers/net/can/grcan.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c
> index e367581faa57..51a10fae2faf 100644
> --- a/drivers/net/can/grcan.c
> +++ b/drivers/net/can/grcan.c
> @@ -1074,6 +1074,12 @@ static int grcan_allocate_dma_buffers(struct net_device *dev,
>
>  	/* Extra GRCAN_BUFFER_ALIGNMENT to allow for alignment */
>  	dma->base_size = lsize + ssize + GRCAN_BUFFER_ALIGNMENT;
> +
> +	/* On 64-bit systems.. GRCAN and GRCANFD can only address 32-bit */
> +	if (dma_set_mask_and_coherent(priv->ofdev_dev, DMA_BIT_MASK(32))) {
> +		netdev_warn(dev, "No suitable DMA available\n");
> +		return -ENOMEM;

Please move this to probe(), return the error code, and use
dev_err_probe() for the error message.

regards,
Marc

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