> -----Original Message-----
> From: fengchengwen <fengcheng...@huawei.com>
> Sent: Thursday, July 15, 2021 1:59 PM
> To: Nipun Gupta <nipun.gu...@nxp.com>; tho...@monjalon.net;
> ferruh.yi...@intel.com; bruce.richard...@intel.com; jer...@marvell.com;
> jerinjac...@gmail.com; andrew.rybche...@oktetlabs.ru
> Cc: dev@dpdk.org; m...@smartsharesystems.com; Hemant Agrawal
> <hemant.agra...@nxp.com>; maxime.coque...@redhat.com;
> honnappa.nagaraha...@arm.com; david.march...@redhat.com;
> sbu...@marvell.com; pkap...@marvell.com; konstantin.anan...@intel.com;
> Gagandeep Singh <g.si...@nxp.com>
> Subject: Re: [PATCH v3] dmadev: introduce DMA device library
>
> On 2021/7/14 20:22, Nipun Gupta wrote:
> > <snip>
> >
> >> +/**
> >> + * A structure used to configure a virtual DMA channel.
> >> + */
> >> +struct rte_dmadev_vchan_conf {
> >> + uint8_t direction;
> >> + /**< Set of supported transfer directions
> >> + * @see RTE_DMA_MEM_TO_MEM
> >> + * @see RTE_DMA_MEM_TO_DEV
> >> + * @see RTE_DMA_DEV_TO_MEM
> >> + * @see RTE_DMA_DEV_TO_DEV
> >> + */
> >> + /** Number of descriptor for the virtual DMA channel */
> >> + uint16_t nb_desc;
> >> + /** 1) Used to describes the port parameter in the device-to-memory
> >> + * transfer scenario.
> >> + * 2) Used to describes the source port parameter in the
> >> + * device-to-device transfer scenario.
> >> + * @see struct rte_dmadev_port_parameters
> >> + */
> >
> > There should also be a configuration to support no response (per Virtual
> Channel),
> > And if that is enabled, user will not be required to call
> > 'rte_dmadev_completed'
> API.
> > This shall also be part of capability.
>
> Do you mean some silent mode? The application only needs to submit requests
> to the
> hardware.
>
> Could you briefly describe the working principles and application scenarios of
> the
> corresponding device?
It is kind of a silent mode w.r.t. the command completion from QDMA.
There could be level of synchronization in the applications at a higher level
due
To which QDMA status dequeue would not be necessary and be an overhead.
In this mode extra data/bytes could be passed with DMA which would indirectly
indicate if DMA is complete or not.
>
> >
> >> + struct rte_dmadev_port_parameters src_port;
> >> + /** 1) Used to describes the port parameter in the memory-to-device-to
> >> + * transfer scenario.
> >> + * 2) Used to describes the destination port parameter in the
> >> + * device-to-device transfer scenario.
> >> + * @see struct rte_dmadev_port_parameters
> >> + */
> >> + struct rte_dmadev_port_parameters dst_port;
> >> +};
> >> +
> >
> > <snip>
> >
> >> +/**
> >> + * @warning
> >> + * @b EXPERIMENTAL: this API may change without prior notice.
> >> + *
> >> + * Enqueue a scatter list copy operation onto the virtual DMA channel.
> >> + *
> >> + * This queues up a scatter list copy operation to be performed by
> >> hardware,
> >> + * but does not trigger hardware to begin that operation.
> >
> > This would need update with the submit flag.
> > The statement should be true only when the flag is set?
> > Similar comment I see on 'rte_dmadev_copy_sg' and 'rte_dma_fill' APIs
>
> OK, will fix in V4
>
> >
> >> + *
> >> + * @param dev_id
> >> + * The identifier of the device.
> >> + * @param vchan
> >> + * The identifier of virtual DMA channel.
> >> + * @param sg
> >> + * The pointer of scatterlist.
> >> + * @param flags
> >> + * An flags for this operation.
> >> + * @see RTE_DMA_OP_FLAG_*
> >> + *
> >> + * @return
> >> + * - 0..UINT16_MAX: index of enqueued copy scatterlist job.
> >> + * - <0: Error code returned by the driver copy scatterlist function.
> >> + */
> >> +__rte_experimental
> >> +static inline int
> >> +rte_dmadev_copy_sg(uint16_t dev_id, uint16_t vchan, const struct
> rte_dma_sg
> >> *sg,
> >> + uint64_t flags)
> >> +{
> >> + struct rte_dmadev *dev = &rte_dmadevices[dev_id];
> >> +#ifdef RTE_DMADEV_DEBUG
> >> + if (!rte_dmadev_is_valid_dev(dev_id) ||
> >> + vchan >= dev->data->dev_conf.max_vchans ||
> >> + sg == NULL)
> >> + return -EINVAL;
> >> + RTE_FUNC_PTR_OR_ERR_RET(*dev->copy_sg, -ENOTSUP);
> >> +#endif
> >> + return (*dev->copy_sg)(dev, vchan, sg, flags);
> >> +}
> >> +
> >
> > .
> >
