Hey Peter,
Sorry for late response on this..
On 01-06-18, 13:24, Peter Ujfalusi wrote:
> If the DMA supports per descriptor metadata it can implement the attach,
> get_ptr/set_len callbacks.
>
> Client drivers must only use either attach or get_ptr/set_len to avoid
> miss configuration.
>
> Wrappers are also added for the metadata_ops:
> dmaengine_desc_attach_metadata()
> dmaengine_desc_get_metadata_ptr()
> dmaengine_desc_set_metadata_len()
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> ---
> Hi,
>
> since attachments are bouncing back, I send the patch separately
>
> Regards,
> Peter
>
> include/linux/dmaengine.h | 50 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 50 insertions(+)
>
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 51fbb861e84b..ac42ace36aa3 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -491,6 +491,18 @@ struct dmaengine_unmap_data {
> dma_addr_t addr[0];
> };
>
> +struct dma_async_tx_descriptor;
> +
> +struct dma_descriptor_metadata_ops {
> + int (*attach)(struct dma_async_tx_descriptor *desc, void *data,
> + size_t len);
How does one detach? When should the client free up the memory, IOW when
does dma driver drop ref to data.
> +
> + void *(*get_ptr)(struct dma_async_tx_descriptor *desc,
> + size_t *payload_len, size_t *max_len);
so what is this supposed to do..?
> + int (*set_len)(struct dma_async_tx_descriptor *desc,
> + size_t payload_len);
attach already has length, so how does this help?
> +};
> +
> /**
> * struct dma_async_tx_descriptor - async transaction descriptor
> * ---dma generic offload fields---
> @@ -520,6 +532,7 @@ struct dma_async_tx_descriptor {
> dma_async_tx_callback_result callback_result;
> void *callback_param;
> struct dmaengine_unmap_data *unmap;
> + struct dma_descriptor_metadata_ops *metadata_ops;
> #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
> struct dma_async_tx_descriptor *next;
> struct dma_async_tx_descriptor *parent;
> @@ -932,6 +945,43 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy(
> len, flags);
> }
>
> +static inline int dmaengine_desc_attach_metadata(
> + struct dma_async_tx_descriptor *desc, void *data, size_t len)
> +{
> + if (!desc)
> + return 0;
> +
> + if (!desc->metadata_ops || !desc->metadata_ops->attach)
> + return -ENOTSUPP;
> +
> + return desc->metadata_ops->attach(desc, data, len);
> +}
> +
> +static inline void *dmaengine_desc_get_metadata_ptr(
> + struct dma_async_tx_descriptor *desc, size_t *payload_len,
> + size_t *max_len)
> +{
> + if (!desc)
> + return NULL;
> +
> + if (!desc->metadata_ops || !desc->metadata_ops->get_ptr)
> + return ERR_PTR(-ENOTSUPP);
> +
> + return desc->metadata_ops->get_ptr(desc, payload_len, max_len);
> +}
> +
> +static inline int dmaengine_desc_set_metadata_len(
> + struct dma_async_tx_descriptor *desc, size_t payload_len)
> +{
> + if (!desc)
> + return 0;
> +
> + if (!desc->metadata_ops || !desc->metadata_ops->set_len)
> + return -ENOTSUPP;
> +
> + return desc->metadata_ops->set_len(desc, payload_len);
> +}
> +
> /**
> * dmaengine_terminate_all() - Terminate all active DMA transfers
> * @chan: The channel for which to terminate the transfers
> --
> Peter
>
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>
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