Re: [PATCH v4 05/19] dmaengine: ti: k3-udma: move ring management functions to k3-udma-common.c

[Frank Li <Frank.li@nxp.com>]

On Fri, Jan 30, 2026 at 04:31:45PM +0530, Sai Sree Kartheek Adivi wrote:
> Relocate the ring management functions such as push, pop, and reset
> from k3-udma.c to k3-udma-common.c file. These operations are
> common across multiple K3 UDMA variants and will be reused by
> future implementations like K3 UDMA v2.
>
> No functional changes intended.
>
> Signed-off-by: Sai Sree Kartheek Adivi <s-adivi@ti.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

>  drivers/dma/ti/k3-udma-common.c | 103 ++++++++++++++++++++++++++++++++
>  drivers/dma/ti/k3-udma.c        | 100 -------------------------------
>  drivers/dma/ti/k3-udma.h        |   4 ++
>  3 files changed, 107 insertions(+), 100 deletions(-)
>
> diff --git a/drivers/dma/ti/k3-udma-common.c b/drivers/dma/ti/k3-udma-common.c
> index 9cb35759c70bb..4dcf986f84d87 100644
> --- a/drivers/dma/ti/k3-udma-common.c
> +++ b/drivers/dma/ti/k3-udma-common.c
> @@ -1239,5 +1239,108 @@ void udma_desc_pre_callback(struct virt_dma_chan *vc,
>  }
>  EXPORT_SYMBOL_GPL(udma_desc_pre_callback);
>
> +int udma_push_to_ring(struct udma_chan *uc, int idx)
> +{
> +	struct udma_desc *d = uc->desc;
> +	struct k3_ring *ring = NULL;
> +	dma_addr_t paddr;
> +
> +	switch (uc->config.dir) {
> +	case DMA_DEV_TO_MEM:
> +		ring = uc->rflow->fd_ring;
> +		break;
> +	case DMA_MEM_TO_DEV:
> +	case DMA_MEM_TO_MEM:
> +		ring = uc->tchan->t_ring;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	/* RX flush packet: idx == -1 is only passed in case of DEV_TO_MEM */
> +	if (idx == -1) {
> +		paddr = udma_get_rx_flush_hwdesc_paddr(uc);
> +	} else {
> +		paddr = udma_curr_cppi5_desc_paddr(d, idx);
> +
> +		wmb(); /* Ensure that writes are not moved over this point */
> +	}
> +
> +	return k3_ringacc_ring_push(ring, &paddr);
> +}
> +EXPORT_SYMBOL_GPL(udma_push_to_ring);
> +
> +int udma_pop_from_ring(struct udma_chan *uc, dma_addr_t *addr)
> +{
> +	struct k3_ring *ring = NULL;
> +	int ret;
> +
> +	switch (uc->config.dir) {
> +	case DMA_DEV_TO_MEM:
> +		ring = uc->rflow->r_ring;
> +		break;
> +	case DMA_MEM_TO_DEV:
> +	case DMA_MEM_TO_MEM:
> +		ring = uc->tchan->tc_ring;
> +		break;
> +	default:
> +		return -ENOENT;
> +	}
> +
> +	ret = k3_ringacc_ring_pop(ring, addr);
> +	if (ret)
> +		return ret;
> +
> +	rmb(); /* Ensure that reads are not moved before this point */
> +
> +	/* Teardown completion */
> +	if (cppi5_desc_is_tdcm(*addr))
> +		return 0;
> +
> +	/* Check for flush descriptor */
> +	if (udma_desc_is_rx_flush(uc, *addr))
> +		return -ENOENT;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(udma_pop_from_ring);
> +
> +void udma_reset_rings(struct udma_chan *uc)
> +{
> +	struct k3_ring *ring1 = NULL;
> +	struct k3_ring *ring2 = NULL;
> +
> +	switch (uc->config.dir) {
> +	case DMA_DEV_TO_MEM:
> +		if (uc->rchan) {
> +			ring1 = uc->rflow->fd_ring;
> +			ring2 = uc->rflow->r_ring;
> +		}
> +		break;
> +	case DMA_MEM_TO_DEV:
> +	case DMA_MEM_TO_MEM:
> +		if (uc->tchan) {
> +			ring1 = uc->tchan->t_ring;
> +			ring2 = uc->tchan->tc_ring;
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	if (ring1)
> +		k3_ringacc_ring_reset_dma(ring1,
> +					  k3_ringacc_ring_get_occ(ring1));
> +	if (ring2)
> +		k3_ringacc_ring_reset(ring2);
> +
> +	/* make sure we are not leaking memory by stalled descriptor */
> +	if (uc->terminated_desc) {
> +		udma_desc_free(&uc->terminated_desc->vd);
> +		uc->terminated_desc = NULL;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(udma_reset_rings);
> +
>  MODULE_DESCRIPTION("Texas Instruments K3 UDMA Common Library");
>  MODULE_LICENSE("GPL v2");
> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
> index 0a1291829611f..214a1ca1e1776 100644
> --- a/drivers/dma/ti/k3-udma.c
> +++ b/drivers/dma/ti/k3-udma.c
> @@ -174,106 +174,6 @@ static bool udma_is_chan_paused(struct udma_chan *uc)
>  	return false;
>  }
>
> -static int udma_push_to_ring(struct udma_chan *uc, int idx)
> -{
> -	struct udma_desc *d = uc->desc;
> -	struct k3_ring *ring = NULL;
> -	dma_addr_t paddr;
> -
> -	switch (uc->config.dir) {
> -	case DMA_DEV_TO_MEM:
> -		ring = uc->rflow->fd_ring;
> -		break;
> -	case DMA_MEM_TO_DEV:
> -	case DMA_MEM_TO_MEM:
> -		ring = uc->tchan->t_ring;
> -		break;
> -	default:
> -		return -EINVAL;
> -	}
> -
> -	/* RX flush packet: idx == -1 is only passed in case of DEV_TO_MEM */
> -	if (idx == -1) {
> -		paddr = udma_get_rx_flush_hwdesc_paddr(uc);
> -	} else {
> -		paddr = udma_curr_cppi5_desc_paddr(d, idx);
> -
> -		wmb(); /* Ensure that writes are not moved over this point */
> -	}
> -
> -	return k3_ringacc_ring_push(ring, &paddr);
> -}
> -
> -static int udma_pop_from_ring(struct udma_chan *uc, dma_addr_t *addr)
> -{
> -	struct k3_ring *ring = NULL;
> -	int ret;
> -
> -	switch (uc->config.dir) {
> -	case DMA_DEV_TO_MEM:
> -		ring = uc->rflow->r_ring;
> -		break;
> -	case DMA_MEM_TO_DEV:
> -	case DMA_MEM_TO_MEM:
> -		ring = uc->tchan->tc_ring;
> -		break;
> -	default:
> -		return -ENOENT;
> -	}
> -
> -	ret = k3_ringacc_ring_pop(ring, addr);
> -	if (ret)
> -		return ret;
> -
> -	rmb(); /* Ensure that reads are not moved before this point */
> -
> -	/* Teardown completion */
> -	if (cppi5_desc_is_tdcm(*addr))
> -		return 0;
> -
> -	/* Check for flush descriptor */
> -	if (udma_desc_is_rx_flush(uc, *addr))
> -		return -ENOENT;
> -
> -	return 0;
> -}
> -
> -static void udma_reset_rings(struct udma_chan *uc)
> -{
> -	struct k3_ring *ring1 = NULL;
> -	struct k3_ring *ring2 = NULL;
> -
> -	switch (uc->config.dir) {
> -	case DMA_DEV_TO_MEM:
> -		if (uc->rchan) {
> -			ring1 = uc->rflow->fd_ring;
> -			ring2 = uc->rflow->r_ring;
> -		}
> -		break;
> -	case DMA_MEM_TO_DEV:
> -	case DMA_MEM_TO_MEM:
> -		if (uc->tchan) {
> -			ring1 = uc->tchan->t_ring;
> -			ring2 = uc->tchan->tc_ring;
> -		}
> -		break;
> -	default:
> -		break;
> -	}
> -
> -	if (ring1)
> -		k3_ringacc_ring_reset_dma(ring1,
> -					  k3_ringacc_ring_get_occ(ring1));
> -	if (ring2)
> -		k3_ringacc_ring_reset(ring2);
> -
> -	/* make sure we are not leaking memory by stalled descriptor */
> -	if (uc->terminated_desc) {
> -		udma_desc_free(&uc->terminated_desc->vd);
> -		uc->terminated_desc = NULL;
> -	}
> -}
> -
>  static void udma_decrement_byte_counters(struct udma_chan *uc, u32 val)
>  {
>  	if (uc->desc->dir == DMA_DEV_TO_MEM) {
> diff --git a/drivers/dma/ti/k3-udma.h b/drivers/dma/ti/k3-udma.h
> index 7c807bd9e178b..4c6e5b946d5cf 100644
> --- a/drivers/dma/ti/k3-udma.h
> +++ b/drivers/dma/ti/k3-udma.h
> @@ -610,6 +610,10 @@ void udma_desc_pre_callback(struct virt_dma_chan *vc,
>  			    struct virt_dma_desc *vd,
>  			    struct dmaengine_result *result);
>
> +int udma_push_to_ring(struct udma_chan *uc, int idx);
> +int udma_pop_from_ring(struct udma_chan *uc, dma_addr_t *addr);
> +void udma_reset_rings(struct udma_chan *uc);
> +
>  /* Direct access to UDMA low lever resources for the glue layer */
>  int xudma_navss_psil_pair(struct udma_dev *ud, u32 src_thread, u32 dst_thread);
>  int xudma_navss_psil_unpair(struct udma_dev *ud, u32 src_thread,
> --
> 2.34.1
>