dmaengine: dma-axi-dmac: Add helper for getting next desc

Add a new helper for getting the next valid struct axi_dmac_desc. This
will be extended in follow up patches to support to gracefully terminate
cyclic transfers.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20260303-axi-dac-cyclic-support-v2-3-0db27b4be95a@analog.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 79c01b7d973280f0eb18025f4e6992f4788fef48..a47e08d3dbbc3dd7498249941cc3a51193e47213 100644 (file)
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -227,10 +227,29 @@ static bool axi_dmac_check_addr(struct axi_dmac_chan *chan, dma_addr_t addr)
        return true;
 }
 
+static struct axi_dmac_desc *axi_dmac_get_next_desc(struct axi_dmac *dmac,
+                                                   struct axi_dmac_chan *chan)
+{
+       struct virt_dma_desc *vdesc;
+       struct axi_dmac_desc *desc;
+
+       if (chan->next_desc)
+               return chan->next_desc;
+
+       vdesc = vchan_next_desc(&chan->vchan);
+       if (!vdesc)
+               return NULL;
+
+       list_move_tail(&vdesc->node, &chan->active_descs);
+       desc = to_axi_dmac_desc(vdesc);
+       chan->next_desc = desc;
+
+       return desc;
+}
+
 static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
 {
        struct axi_dmac *dmac = chan_to_axi_dmac(chan);
-       struct virt_dma_desc *vdesc;
        struct axi_dmac_desc *desc;
        struct axi_dmac_sg *sg;
        unsigned int flags = 0;
@@ -240,16 +259,10 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
        if (val) /* Queue is full, wait for the next SOT IRQ */
                return;
 
-       desc = chan->next_desc;
+       desc = axi_dmac_get_next_desc(dmac, chan);
+       if (!desc)
+               return;
 
-       if (!desc) {
-               vdesc = vchan_next_desc(&chan->vchan);
-               if (!vdesc)
-                       return;
-               list_move_tail(&vdesc->node, &chan->active_descs);
-               desc = to_axi_dmac_desc(vdesc);
-               chan->next_desc = desc;
-       }
        sg = &desc->sg[desc->num_submitted];
 
        /* Already queued in cyclic mode. Wait for it to finish */