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From:   Jan Kuliga <jankul@alatek.krakow.pl>
To:     lizhi.hou@amd.com, brian.xu@amd.com, raj.kumar.rampelli@amd.com,
        vkoul@kernel.org, michal.simek@amd.com, dmaengine@vger.kernel.org,
        linux-kernel@vger.kernel.org, miquel.raynal@bootlin.com
Cc:     jankul@alatek.krakow.pl
Subject: [PATCH v4 7/8] dmaengine: xilinx: xdma: Prepare the introduction of interleaved DMA transfers
Date:   Fri,  8 Dec 2023 14:49:28 +0100
Message-Id: <20231208134929.49523-8-jankul@alatek.krakow.pl>
In-Reply-To: <20231208134838.49500-1-jankul@alatek.krakow.pl>
References: <20231208134838.49500-1-jankul@alatek.krakow.pl>
MIME-Version: 1.0
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Make generic code generic. As descriptor-filling logic stays the same
regardless of a dmaengine's type of transfer, it is possible to write
the descriptor-filling function in a generic way, so that it can be used
for every single type of transfer preparation callback.

Signed-off-by: Jan Kuliga <jankul@alatek.krakow.pl>
---
 drivers/dma/xilinx/xdma.c | 101 +++++++++++++++++++++-----------------
 1 file changed, 57 insertions(+), 44 deletions(-)

diff --git a/drivers/dma/xilinx/xdma.c b/drivers/dma/xilinx/xdma.c
index dbde6905acc7..c8ac047249bc 100644
--- a/drivers/dma/xilinx/xdma.c
+++ b/drivers/dma/xilinx/xdma.c
@@ -542,6 +542,43 @@ static void xdma_synchronize(struct dma_chan *chan)
 	vchan_synchronize(&xdma_chan->vchan);
 }

+/**
+ * xdma_fill_descs - Fill hardware descriptors with contiguous memory bl=
ock addresses
+ * @sw_desc - tx descriptor state container
+ * @src_addr - Value for a ->src_addr field of a first descriptor
+ * @dst_addr - Value for a ->dst_addr field of a first descriptor
+ * @size - Total size of a contiguous memory block
+ * @filled_descs_num - Number of filled hardware descriptors for corresp=
onding sw_desc
+ */
+static inline u32 xdma_fill_descs(struct xdma_desc *sw_desc, u64 src_add=
r,
+				u64 dst_addr, u32 size, u32 filled_descs_num)
+{
+	u32 left =3D size, len, desc_num =3D filled_descs_num;
+	struct xdma_desc_block *dblk;
+	struct xdma_hw_desc *desc;
+
+	dblk =3D sw_desc->desc_blocks + (desc_num / XDMA_DESC_ADJACENT);
+	desc =3D dblk->virt_addr;
+	desc +=3D desc_num & XDMA_DESC_ADJACENT_MASK;
+	do {
+		len =3D min_t(u32, left, XDMA_DESC_BLEN_MAX);
+		/* set hardware descriptor */
+		desc->bytes =3D cpu_to_le32(len);
+		desc->src_addr =3D cpu_to_le64(src_addr);
+		desc->dst_addr =3D cpu_to_le64(dst_addr);
+		if (!(++desc_num & XDMA_DESC_ADJACENT_MASK))
+			desc =3D (++dblk)->virt_addr;
+		else
+			desc++;
+
+		src_addr +=3D len;
+		dst_addr +=3D len;
+		left -=3D len;
+	} while (left);
+
+	return desc_num - filled_descs_num;
+}
+
/**
  * xdma_prep_device_sg - prepare a descriptor for a DMA transaction
  * @chan: DMA channel pointer
@@ -558,13 +595,10 @@ xdma_prep_device_sg(struct dma_chan *chan, struct s=
catterlist *sgl,
 {
 	struct xdma_chan *xdma_chan =3D to_xdma_chan(chan);
 	struct dma_async_tx_descriptor *tx_desc;
-	u32 desc_num =3D 0, i, len, rest;
-	struct xdma_desc_block *dblk;
-	struct xdma_hw_desc *desc;
 	struct xdma_desc *sw_desc;
-	u64 dev_addr, *src, *dst;
+	u32 desc_num =3D 0, i;
+	u64 addr, dev_addr, *src, *dst;
 	struct scatterlist *sg;
-	u64 addr;

 	for_each_sg(sgl, sg, sg_len, i)
 		desc_num +=3D DIV_ROUND_UP(sg_dma_len(sg), XDMA_DESC_BLEN_MAX);
@@ -584,32 +618,11 @@ xdma_prep_device_sg(struct dma_chan *chan, struct s=
catterlist *sgl,
 		dst =3D &addr;
 	}

-	dblk =3D sw_desc->desc_blocks;
-	desc =3D dblk->virt_addr;
-	desc_num =3D 1;
+	desc_num =3D 0;
 	for_each_sg(sgl, sg, sg_len, i) {
 		addr =3D sg_dma_address(sg);
-		rest =3D sg_dma_len(sg);
-
-		do {
-			len =3D min_t(u32, rest, XDMA_DESC_BLEN_MAX);
-			/* set hardware descriptor */
-			desc->bytes =3D cpu_to_le32(len);
-			desc->src_addr =3D cpu_to_le64(*src);
-			desc->dst_addr =3D cpu_to_le64(*dst);
-
-			if (!(desc_num & XDMA_DESC_ADJACENT_MASK)) {
-				dblk++;
-				desc =3D dblk->virt_addr;
-			} else {
-				desc++;
-			}
-
-			desc_num++;
-			dev_addr +=3D len;
-			addr +=3D len;
-			rest -=3D len;
-		} while (rest);
+		desc_num +=3D xdma_fill_descs(sw_desc, *src, *dst, sg_dma_len(sg), des=
c_num);
+		dev_addr +=3D sg_dma_len(sg);
 	}

 	tx_desc =3D vchan_tx_prep(&xdma_chan->vchan, &sw_desc->vdesc, flags);
@@ -643,9 +656,9 @@ xdma_prep_dma_cyclic(struct dma_chan *chan, dma_addr_=
t address,
 	struct xdma_device *xdev =3D xdma_chan->xdev_hdl;
 	unsigned int periods =3D size / period_size;
 	struct dma_async_tx_descriptor *tx_desc;
-	struct xdma_desc_block *dblk;
-	struct xdma_hw_desc *desc;
 	struct xdma_desc *sw_desc;
+	u64 addr, dev_addr, *src, *dst;
+	u32 desc_num;
 	unsigned int i;

 	/*
@@ -670,21 +683,21 @@ xdma_prep_dma_cyclic(struct dma_chan *chan, dma_add=
r_t address,
 	sw_desc->period_size =3D period_size;
 	sw_desc->dir =3D dir;

-	dblk =3D sw_desc->desc_blocks;
-	desc =3D dblk->virt_addr;
+	addr =3D address;
+	if (dir =3D=3D DMA_MEM_TO_DEV) {
+		dev_addr =3D xdma_chan->cfg.dst_addr;
+		src =3D &addr;
+		dst =3D &dev_addr;
+	} else {
+		dev_addr =3D xdma_chan->cfg.src_addr;
+		src =3D &dev_addr;
+		dst =3D &addr;
+	}

-	/* fill hardware descriptor */
+	desc_num =3D 0;
 	for (i =3D 0; i < periods; i++) {
-		desc->bytes =3D cpu_to_le32(period_size);
-		if (dir =3D=3D DMA_MEM_TO_DEV) {
-			desc->src_addr =3D cpu_to_le64(address + i * period_size);
-			desc->dst_addr =3D cpu_to_le64(xdma_chan->cfg.dst_addr);
-		} else {
-			desc->src_addr =3D cpu_to_le64(xdma_chan->cfg.src_addr);
-			desc->dst_addr =3D cpu_to_le64(address + i * period_size);
-		}
-
-		desc++;
+		desc_num +=3D xdma_fill_descs(sw_desc, *src, *dst, period_size, desc_n=
um);
+		addr +=3D i * period_size;
 	}

	tx_desc =3D vchan_tx_prep(&xdma_chan->vchan, &sw_desc->vdesc, flags);
--
2.34.1