[PATCH v2 2/3] dma/ae4dma: add control path operations

[David Marchand]

On Mon, 25 May 2026 at 20:43, Raghavendra Ningoji
<raghavendra.ningoji at amd.com> wrote:
>
> Implement the dmadev control path for the AMD AE4DMA PMD.
>
> This commit adds:
>  - dev_configure / vchan_setup: accept a single virtual channel per
>    dmadev and clamp the requested ring size to the hardware maximum
>    of 32 descriptors (rounded up to a power of two).
>  - dev_start / dev_stop / dev_close: program the per-queue control
>    register to enable/disable the hardware queue and release the
>    descriptor ring memzone on close.
>  - dev_info_get: advertise RTE_DMA_CAPA_MEM_TO_MEM and the fixed
>    ring depth.
>  - dev_dump: print the queue identifiers, ring layout and software
>    completion counters.
>  - stats_get / stats_reset: expose submitted / completed / errors
>    counters maintained by the driver.
>  - vchan_status: report IDLE / ACTIVE based on hardware read_idx vs
>    write_idx, and HALTED_ERROR when the queue is not enabled.
>
> The dmadev framework is wired through dev_ops in ae4dma_dmadev_create().
>
> Signed-off-by: Raghavendra Ningoji <raghavendra.ningoji at amd.com>
> ---
>  drivers/dma/ae4dma/ae4dma_dmadev.c | 223 +++++++++++++++++++++++++++++
>  1 file changed, 223 insertions(+)
>
> diff --git a/drivers/dma/ae4dma/ae4dma_dmadev.c b/drivers/dma/ae4dma/ae4dma_dmadev.c
> index 76de2cde45..dfda723c13 100644
> --- a/drivers/dma/ae4dma/ae4dma_dmadev.c
> +++ b/drivers/dma/ae4dma/ae4dma_dmadev.c
> @@ -53,6 +53,215 @@ ae4dma_queue_dma_zone_reserve(const char *queue_name,
>                         socket_id, RTE_MEMZONE_IOVA_CONTIG, queue_size);
>  }
>
> +/* Configure a device. */
> +static int
> +ae4dma_dev_configure(struct rte_dma_dev *dev __rte_unused,
> +               const struct rte_dma_conf *dev_conf,
> +               uint32_t conf_sz)
> +{
> +       if (sizeof(struct rte_dma_conf) != conf_sz)
> +               return -EINVAL;
> +
> +       if (dev_conf->nb_vchans != 1)
> +               return -EINVAL;
> +
> +       return 0;
> +}
> +
> +/* Setup a virtual channel for AE4DMA, only 1 vchan is supported per dmadev. */
> +static int
> +ae4dma_vchan_setup(struct rte_dma_dev *dev, uint16_t vchan __rte_unused,
> +               const struct rte_dma_vchan_conf *qconf, uint32_t qconf_sz)
> +{
> +       struct ae4dma_dmadev *ae4dma = dev->fp_obj->dev_private;
> +       struct ae4dma_cmd_queue *cmd_q = &ae4dma->cmd_q;
> +       uint16_t max_desc = qconf->nb_desc;
> +
> +       if (sizeof(struct rte_dma_vchan_conf) != qconf_sz)
> +               return -EINVAL;
> +
> +       if (max_desc < 2)
> +               return -EINVAL;
> +
> +       if (!rte_is_power_of_2(max_desc))
> +               max_desc = rte_align32pow2(max_desc);
> +
> +       if (max_desc > AE4DMA_DESCRIPTORS_PER_CMDQ) {
> +               AE4DMA_PMD_DEBUG("DMA dev %u nb_desc clamped to %u",
> +                               dev->data->dev_id, AE4DMA_DESCRIPTORS_PER_CMDQ);
> +               max_desc = AE4DMA_DESCRIPTORS_PER_CMDQ;
> +       }
> +
> +       cmd_q->qcfg = *qconf;
> +       cmd_q->qcfg.nb_desc = max_desc;
> +
> +       /* Ensure all counters are reset, if reconfiguring/restarting device. */
> +       memset(&cmd_q->stats, 0, sizeof(cmd_q->stats));
> +       return 0;
> +}
> +
> +/* Start a configured device. */
> +static int
> +ae4dma_dev_start(struct rte_dma_dev *dev)
> +{
> +       struct ae4dma_dmadev *ae4dma = dev->fp_obj->dev_private;
> +       struct ae4dma_cmd_queue *cmd_q = &ae4dma->cmd_q;
> +       uint16_t nb = cmd_q->qcfg.nb_desc;
> +
> +       if (nb == 0)
> +               return -EBUSY;
> +
> +       /* Program ring depth expected by hardware. */
> +       AE4DMA_WRITE_REG(&cmd_q->hwq_regs->max_idx, nb);
> +       return 0;
> +}
> +
> +/* Stop a configured device. */
> +static int
> +ae4dma_dev_stop(struct rte_dma_dev *dev)
> +{
> +       struct ae4dma_dmadev *ae4dma = dev->fp_obj->dev_private;
> +       struct ae4dma_cmd_queue *cmd_q = &ae4dma->cmd_q;
> +
> +       if (cmd_q->hwq_regs != NULL)
> +               AE4DMA_WRITE_REG(&cmd_q->hwq_regs->control_reg.control_raw,
> +                               AE4DMA_CMD_QUEUE_DISABLE);
> +       return 0;
> +}
> +
> +/* Get device information of a device. */
> +static int
> +ae4dma_dev_info_get(const struct rte_dma_dev *dev, struct rte_dma_info *info,
> +               uint32_t size)
> +{
> +       if (size < sizeof(*info))
> +               return -EINVAL;
> +       info->dev_name = dev->device->name;

The dmadev library sets this field in rte_dma_info_get().
Please remove.


> +       info->dev_capa = RTE_DMA_CAPA_MEM_TO_MEM;
> +       info->max_vchans = 1;
> +       info->min_desc = 2;
> +       info->max_desc = AE4DMA_DESCRIPTORS_PER_CMDQ;
> +       info->nb_vchans = 1;
> +       return 0;
> +}
> +
> +/* Close a configured device. */
> +static int
> +ae4dma_dev_close(struct rte_dma_dev *dev)
> +{
> +       struct ae4dma_dmadev *ae4dma = dev->fp_obj->dev_private;
> +       struct ae4dma_cmd_queue *cmd_q = &ae4dma->cmd_q;
> +
> +       if (cmd_q->hwq_regs != NULL)
> +               AE4DMA_WRITE_REG(&cmd_q->hwq_regs->control_reg.control_raw,
> +                               AE4DMA_CMD_QUEUE_DISABLE);
> +
> +       if (cmd_q->memz_name[0] != '\0') {
> +               const struct rte_memzone *mz = rte_memzone_lookup(cmd_q->memz_name);

Rather than resolve again, can't you store the reference to the
memzone in the priv pointer at probe time?


> +
> +               if (mz != NULL)
> +                       rte_memzone_free(mz);

No need to test for NULL.


> +       }
> +       cmd_q->qbase_desc = NULL;
> +       cmd_q->qbase_addr = NULL;
> +       cmd_q->qbase_phys_addr = 0;
> +       return 0;
> +}

[snip]


-- 
David Marchand