RE: [PATCH 1/3] dmaengine: Add support for 2D DMA operation

[Pankaj Dubey]

> -----Original Message-----
> From: Aatif Mushtaq <aatif4.m@xxxxxxxxxxx>
> Sent: Monday, February 10, 2025 11:49 AM
> To: vkoul@xxxxxxxxxx; dmaengine@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Cc: pankaj.dubey@xxxxxxxxxxx; aswani.reddy@xxxxxxxxxxx; Aatif Mushtaq
> <aatif4.m@xxxxxxxxxxx>
> Subject: [PATCH 1/3] dmaengine: Add support for 2D DMA operation
> 
> Add a new dma engine API to support 2D DMA operations.
> The API will be used to get the descriptor for 2D transfer based on
> the 16-bit immediate to define the stride length between consecuitive
16-bit immediate (what? Data?)
Run spell check consecuitive -> consecutive
> source address or destination address after every DMA load and
> store instruction is processed.
> 
> Signed-off-by: Aatif Mushtaq <aatif4.m@xxxxxxxxxxx>
> ---
>  include/linux/dmaengine.h | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index b137fdb56093..8a73b2147983 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -833,6 +833,7 @@ struct dma_filter {
>   *	be called after period_len bytes have been transferred.
>   * @device_prep_interleaved_dma: Transfer expression in a generic way.
>   * @device_prep_dma_imm_data: DMA's 8 byte immediate data to the dst
> address
> + * @device_prep_2d_dma_memcpy: prepares a 2D memcpy operation

prepares -> Prepares (P should be in CAPS)

>   * @device_caps: May be used to override the generic DMA slave capabilities
>   *	with per-channel specific ones
>   * @device_config: Pushes a new configuration to a channel, return 0 or an
> error
> @@ -938,6 +939,9 @@ struct dma_device {
>  	struct dma_async_tx_descriptor *(*device_prep_dma_imm_data)(
>  		struct dma_chan *chan, dma_addr_t dst, u64 data,
>  		unsigned long flags);
> +	struct dma_async_tx_descriptor *(*device_prep_2d_dma_memcpy)(
> +		struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
> +		size_t len, u16 src_imm, u16 dest_imm, unsigned long flags);
> 
>  	void (*device_caps)(struct dma_chan *chan, struct dma_slave_caps
> *caps);
>  	int (*device_config)(struct dma_chan *chan, struct dma_slave_config
> *config);
> @@ -1087,6 +1091,27 @@ static inline struct dma_async_tx_descriptor
> *dmaengine_prep_dma_memcpy(
>  						    len, flags);
>  }
> 
> +/**
> + * device_prep_2d_dma_memcpy() - Prepare a DMA 2D memcpy descriptor.
> + * @chan: The channel to be used for this descriptor
> + * @dest: Address of the destination data for a DMA channel
> + * @src: Address of the source data for a DMA channel
> + * @len: The total size of data
> + * @src_imm: The immediate value to be added to the src address register

src -> source

> + * @dest_imm: The immediate value to be added to the dst address register

dst -> destination 
avoid using non-standard short forms in comment except variable names.

> + * @flags: DMA engine flags
> + */
> +static inline struct dma_async_tx_descriptor *device_prep_2d_dma_memcpy(
> +		struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
> +		size_t len, u16 src_imm, u16 dest_imm, unsigned long flags)
> +{
> +	if (!chan || !chan->device || !chan->device-
> >device_prep_2d_dma_memcpy)
> +		return NULL;
> +
> +	return chan->device->device_prep_2d_dma_memcpy(chan, dest, src,
> len,
> +						       src_imm, dest_imm, flags);
> +}
> +
>  static inline bool dmaengine_is_metadata_mode_supported(struct dma_chan
> *chan,
>  		enum dma_desc_metadata_mode mode)
>  {
> --
> 2.17.1