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-rw-r--r--drivers/dma/dma-axi-dmac.c99
1 files changed, 98 insertions, 1 deletions
diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 9e6b8940e8d2..0101c0ae24c8 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -63,6 +63,8 @@
 #define AXI_DMAC_REG_STATUS		0x430
 #define AXI_DMAC_REG_CURRENT_SRC_ADDR	0x434
 #define AXI_DMAC_REG_CURRENT_DEST_ADDR	0x438
+#define AXI_DMAC_REG_PARTIAL_XFER_LEN	0x44c
+#define AXI_DMAC_REG_PARTIAL_XFER_ID	0x450
 
 #define AXI_DMAC_CTRL_ENABLE		BIT(0)
 #define AXI_DMAC_CTRL_PAUSE		BIT(1)
@@ -72,6 +74,9 @@
 
 #define AXI_DMAC_FLAG_CYCLIC		BIT(0)
 #define AXI_DMAC_FLAG_LAST		BIT(1)
+#define AXI_DMAC_FLAG_PARTIAL_REPORT	BIT(2)
+
+#define AXI_DMAC_FLAG_PARTIAL_XFER_DONE BIT(31)
 
 /* The maximum ID allocated by the hardware is 31 */
 #define AXI_DMAC_SG_UNUSED 32U
@@ -84,6 +89,7 @@ struct axi_dmac_sg {
 	unsigned int dest_stride;
 	unsigned int src_stride;
 	unsigned int id;
+	unsigned int partial_len;
 	bool schedule_when_free;
 };
 
@@ -113,6 +119,7 @@ struct axi_dmac_chan {
 	unsigned int address_align_mask;
 	unsigned int length_align_mask;
 
+	bool hw_partial_xfer;
 	bool hw_cyclic;
 	bool hw_2d;
 };
@@ -244,6 +251,9 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
 		desc->num_sgs == 1)
 		flags |= AXI_DMAC_FLAG_CYCLIC;
 
+	if (chan->hw_partial_xfer)
+		flags |= AXI_DMAC_FLAG_PARTIAL_REPORT;
+
 	axi_dmac_write(dmac, AXI_DMAC_REG_X_LENGTH, sg->x_len - 1);
 	axi_dmac_write(dmac, AXI_DMAC_REG_Y_LENGTH, sg->y_len - 1);
 	axi_dmac_write(dmac, AXI_DMAC_REG_FLAGS, flags);
@@ -256,6 +266,82 @@ static struct axi_dmac_desc *axi_dmac_active_desc(struct axi_dmac_chan *chan)
 		struct axi_dmac_desc, vdesc.node);
 }
 
+static inline unsigned int axi_dmac_total_sg_bytes(struct axi_dmac_chan *chan,
+	struct axi_dmac_sg *sg)
+{
+	if (chan->hw_2d)
+		return sg->x_len * sg->y_len;
+	else
+		return sg->x_len;
+}
+
+static void axi_dmac_dequeue_partial_xfers(struct axi_dmac_chan *chan)
+{
+	struct axi_dmac *dmac = chan_to_axi_dmac(chan);
+	struct axi_dmac_desc *desc;
+	struct axi_dmac_sg *sg;
+	u32 xfer_done, len, id, i;
+	bool found_sg;
+
+	do {
+		len = axi_dmac_read(dmac, AXI_DMAC_REG_PARTIAL_XFER_LEN);
+		id  = axi_dmac_read(dmac, AXI_DMAC_REG_PARTIAL_XFER_ID);
+
+		found_sg = false;
+		list_for_each_entry(desc, &chan->active_descs, vdesc.node) {
+			for (i = 0; i < desc->num_sgs; i++) {
+				sg = &desc->sg[i];
+				if (sg->id == AXI_DMAC_SG_UNUSED)
+					continue;
+				if (sg->id == id) {
+					sg->partial_len = len;
+					found_sg = true;
+					break;
+				}
+			}
+			if (found_sg)
+				break;
+		}
+
+		if (found_sg) {
+			dev_dbg(dmac->dma_dev.dev,
+				"Found partial segment id=%u, len=%u\n",
+				id, len);
+		} else {
+			dev_warn(dmac->dma_dev.dev,
+				 "Not found partial segment id=%u, len=%u\n",
+				 id, len);
+		}
+
+		/* Check if we have any more partial transfers */
+		xfer_done = axi_dmac_read(dmac, AXI_DMAC_REG_TRANSFER_DONE);
+		xfer_done = !(xfer_done & AXI_DMAC_FLAG_PARTIAL_XFER_DONE);
+
+	} while (!xfer_done);
+}
+
+static void axi_dmac_compute_residue(struct axi_dmac_chan *chan,
+	struct axi_dmac_desc *active)
+{
+	struct dmaengine_result *rslt = &active->vdesc.tx_result;
+	unsigned int start = active->num_completed - 1;
+	struct axi_dmac_sg *sg;
+	unsigned int i, total;
+
+	rslt->result = DMA_TRANS_NOERROR;
+	rslt->residue = 0;
+
+	/*
+	 * We get here if the last completed segment is partial, which
+	 * means we can compute the residue from that segment onwards
+	 */
+	for (i = start; i < active->num_sgs; i++) {
+		sg = &active->sg[i];
+		total = axi_dmac_total_sg_bytes(chan, sg);
+		rslt->residue += (total - sg->partial_len);
+	}
+}
+
 static bool axi_dmac_transfer_done(struct axi_dmac_chan *chan,
 	unsigned int completed_transfers)
 {
@@ -267,6 +353,10 @@ static bool axi_dmac_transfer_done(struct axi_dmac_chan *chan,
 	if (!active)
 		return false;
 
+	if (chan->hw_partial_xfer &&
+	    (completed_transfers & AXI_DMAC_FLAG_PARTIAL_XFER_DONE))
+		axi_dmac_dequeue_partial_xfers(chan);
+
 	do {
 		sg = &active->sg[active->num_completed];
 		if (sg->id == AXI_DMAC_SG_UNUSED) /* Not yet submitted */
@@ -280,10 +370,14 @@ static bool axi_dmac_transfer_done(struct axi_dmac_chan *chan,
 			start_next = true;
 		}
 
+		if (sg->partial_len)
+			axi_dmac_compute_residue(chan, active);
+
 		if (active->cyclic)
 			vchan_cyclic_callback(&active->vdesc);
 
-		if (active->num_completed == active->num_sgs) {
+		if (active->num_completed == active->num_sgs ||
+		    sg->partial_len) {
 			if (active->cyclic) {
 				active->num_completed = 0; /* wrap around */
 			} else {
@@ -674,6 +768,9 @@ static int axi_dmac_detect_caps(struct axi_dmac *dmac)
 		return -ENODEV;
 	}
 
+	if (version >= ADI_AXI_PCORE_VER(4, 2, 'a'))
+		chan->hw_partial_xfer = true;
+
 	if (version >= ADI_AXI_PCORE_VER(4, 1, 'a')) {
 		axi_dmac_write(dmac, AXI_DMAC_REG_X_LENGTH, 0x00);
 		chan->length_align_mask =