[PATCH v3 2/2] dmaengine: sprd: Add Spreadtrum DMA configuration

[Baolin Wang]

From: Eric Long <eric.long@xxxxxxxxxxxxxx>

This patch adds the 'device_config' and 'device_prep_slave_sg' interfaces
for users to configure DMA, as well as adding one 'struct sprd_dma_config'
structure to save Spreadtrum DMA configuration for each DMA channel.

Signed-off-by: Eric Long <eric.long@xxxxxxxxxxxxxx>
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
---
Changes since v2:
 - Remove src/dst from struct sprd_dma_config.
 - Simplify sprd_dma_get_datawidth()/sprd_dma_get_step().
 - Change some logic to make code more readable.
 - Other optimization.

Changes since v1:
 - Fix the incorrect parameter type of sprd_dma_get_step().
---
 drivers/dma/sprd-dma.c       |  213 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/dma/sprd-dma.h |    4 +
 2 files changed, 217 insertions(+)

diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
index 924ada4..00fcec4 100644
--- a/drivers/dma/sprd-dma.c
+++ b/drivers/dma/sprd-dma.c
@@ -100,6 +100,8 @@
 #define SPRD_DMA_DES_DATAWIDTH_OFFSET	28
 #define SPRD_DMA_SWT_MODE_OFFSET	26
 #define SPRD_DMA_REQ_MODE_OFFSET	24
+#define SPRD_DMA_WRAP_SEL_OFFSET	23
+#define SPRD_DMA_WRAP_EN_OFFSET		22
 #define SPRD_DMA_REQ_MODE_MASK		GENMASK(1, 0)
 #define SPRD_DMA_FIX_SEL_OFFSET		21
 #define SPRD_DMA_FIX_EN_OFFSET		20
@@ -154,6 +156,31 @@ struct sprd_dma_chn_hw {
 	u32 des_blk_step;
 };
 
+/*
+ * struct sprd_dma_config - DMA configuration structure
+ * @cfg: dma slave channel runtime config
+ * @block_len: specify one block transfer length
+ * @transcation_len: specify one transcation transfer length
+ * @src_step: source transfer step
+ * @dst_step: destination transfer step
+ * @wrap_ptr: wrap pointer address, once the transfer address reaches the
+ * 'wrap_ptr', the next transfer address will jump to the 'wrap_to' address.
+ * @wrap_to: wrap jump to address
+ * @req_mode: specify the DMA request mode
+ * @int_mode: specify the DMA interrupt type
+ */
+struct sprd_dma_config {
+	struct dma_slave_config cfg;
+	u32 block_len;
+	u32 transcation_len;
+	u32 src_step;
+	u32 dst_step;
+	phys_addr_t wrap_ptr;
+	phys_addr_t wrap_to;
+	enum sprd_dma_req_mode req_mode;
+	enum sprd_dma_int_type int_mode;
+};
+
 /* dma request description */
 struct sprd_dma_desc {
 	struct virt_dma_desc	vd;
@@ -164,6 +191,7 @@ struct sprd_dma_desc {
 struct sprd_dma_chn {
 	struct virt_dma_chan	vc;
 	void __iomem		*chn_base;
+	struct sprd_dma_config	slave_cfg;
 	u32			chn_num;
 	u32			dev_id;
 	struct sprd_dma_desc	*cur_desc;
@@ -552,6 +580,113 @@ static void sprd_dma_issue_pending(struct dma_chan *chan)
 	spin_unlock_irqrestore(&schan->vc.lock, flags);
 }
 
+static enum sprd_dma_datawidth
+sprd_dma_get_datawidth(enum dma_slave_buswidth buswidth)
+{
+	switch (buswidth) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+	case DMA_SLAVE_BUSWIDTH_8_BYTES:
+		return ffs(buswidth) - 1;
+	default:
+		return SPRD_DMA_DATAWIDTH_4_BYTES;
+	}
+}
+
+static u32 sprd_dma_get_step(enum dma_slave_buswidth buswidth)
+{
+	switch (buswidth) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+	case DMA_SLAVE_BUSWIDTH_8_BYTES:
+		return buswidth;
+
+	default:
+		return SPRD_DMA_DWORD_STEP;
+	}
+}
+
+static int sprd_dma_config(struct dma_chan *chan, struct sprd_dma_desc *sdesc,
+			   dma_addr_t src, dma_addr_t dst,
+			   struct sprd_dma_config *slave_cfg)
+{
+	struct sprd_dma_dev *sdev = to_sprd_dma_dev(chan);
+	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
+	struct sprd_dma_chn_hw *hw = &sdesc->chn_hw;
+	u32 fix_mode = 0, fix_en = 0, wrap_en = 0, wrap_mode = 0;
+	u32 src_datawidth, dst_datawidth, temp;
+
+	if (slave_cfg->cfg.slave_id)
+		schan->dev_id = slave_cfg->cfg.slave_id;
+
+	hw->cfg = SPRD_DMA_DONOT_WAIT_BDONE << SPRD_DMA_WAIT_BDONE_OFFSET;
+
+	temp = slave_cfg->wrap_ptr & SPRD_DMA_LOW_ADDR_MASK;
+	temp |= (src >> SPRD_DMA_HIGH_ADDR_OFFSET) & SPRD_DMA_HIGH_ADDR_MASK;
+	hw->wrap_ptr = temp;
+
+	temp = slave_cfg->wrap_to & SPRD_DMA_LOW_ADDR_MASK;
+	temp |= (dst >> SPRD_DMA_HIGH_ADDR_OFFSET) & SPRD_DMA_HIGH_ADDR_MASK;
+	hw->wrap_to = temp;
+
+	hw->src_addr = src & SPRD_DMA_LOW_ADDR_MASK;
+	hw->des_addr = dst & SPRD_DMA_LOW_ADDR_MASK;
+
+	if ((slave_cfg->src_step != 0 && slave_cfg->dst_step != 0)
+	    || (slave_cfg->src_step | slave_cfg->dst_step) == 0) {
+		fix_en = 0;
+	} else {
+		fix_en = 1;
+		if (slave_cfg->src_step)
+			fix_mode = 1;
+		else
+			fix_mode = 0;
+	}
+
+	if (slave_cfg->wrap_ptr && slave_cfg->wrap_to) {
+		wrap_en = 1;
+		if (slave_cfg->wrap_to == src) {
+			wrap_mode = 0;
+		} else if (slave_cfg->wrap_to == dst) {
+			wrap_mode = 1;
+		} else {
+			dev_err(sdev->dma_dev.dev, "invalid wrap mode\n");
+			return -EINVAL;
+		}
+	}
+
+	hw->intc = slave_cfg->int_mode | SPRD_DMA_CFG_ERR_INT_EN;
+
+	src_datawidth = sprd_dma_get_datawidth(slave_cfg->cfg.src_addr_width);
+	dst_datawidth = sprd_dma_get_datawidth(slave_cfg->cfg.dst_addr_width);
+
+	temp = src_datawidth << SPRD_DMA_SRC_DATAWIDTH_OFFSET;
+	temp |= dst_datawidth << SPRD_DMA_DES_DATAWIDTH_OFFSET;
+	temp |= slave_cfg->req_mode << SPRD_DMA_REQ_MODE_OFFSET;
+	temp |= wrap_mode << SPRD_DMA_WRAP_SEL_OFFSET;
+	temp |= wrap_en << SPRD_DMA_WRAP_EN_OFFSET;
+	temp |= fix_mode << SPRD_DMA_FIX_SEL_OFFSET;
+	temp |= fix_en << SPRD_DMA_FIX_EN_OFFSET;
+	temp |= slave_cfg->cfg.src_maxburst & SPRD_DMA_FRG_LEN_MASK;
+	hw->frg_len = temp;
+
+	hw->blk_len = slave_cfg->block_len & SPRD_DMA_BLK_LEN_MASK;
+	hw->trsc_len = slave_cfg->transcation_len & SPRD_DMA_TRSC_LEN_MASK;
+
+	temp = (slave_cfg->dst_step & SPRD_DMA_TRSF_STEP_MASK) <<
+		SPRD_DMA_DEST_TRSF_STEP_OFFSET;
+	temp |= (slave_cfg->src_step & SPRD_DMA_TRSF_STEP_MASK) <<
+		SPRD_DMA_SRC_TRSF_STEP_OFFSET;
+	hw->trsf_step = temp;
+
+	hw->frg_step = 0;
+	hw->src_blk_step = 0;
+	hw->des_blk_step = 0;
+	return 0;
+}
+
 static struct dma_async_tx_descriptor *
 sprd_dma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 			 size_t len, unsigned long flags)
@@ -607,6 +742,82 @@ static void sprd_dma_issue_pending(struct dma_chan *chan)
 	return vchan_tx_prep(&schan->vc, &sdesc->vd, flags);
 }
 
+static void sprd_dma_fill_config(struct sprd_dma_config *slave_cfg,
+				 u32 src_step, u32 dst_step, u32 len,
+				 unsigned long flags)
+{
+	slave_cfg->src_step = src_step;
+	slave_cfg->dst_step = dst_step;
+	slave_cfg->block_len = len;
+	slave_cfg->transcation_len = len;
+	slave_cfg->req_mode =
+		(flags >> SPRD_DMA_REQ_SHIFT) & SPRD_DMA_REQ_MODE_MASK;
+	slave_cfg->int_mode = flags & SPRD_DMA_INT_MASK;
+}
+
+static struct dma_async_tx_descriptor *
+sprd_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+		       unsigned int sglen, enum dma_transfer_direction dir,
+		       unsigned long flags, void *context)
+{
+	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
+	struct sprd_dma_config *slave_cfg = &schan->slave_cfg;
+	u32 src_step = 0, dst_step = 0, len = 0;
+	dma_addr_t src = 0, dst = 0;
+	struct sprd_dma_desc *sdesc;
+	struct scatterlist *sg;
+	int ret, i;
+
+	/* TODO: now we only support one sg for each DMA configuration. */
+	if (!is_slave_direction(dir) || sglen > 1)
+		return NULL;
+
+	sdesc = kzalloc(sizeof(*sdesc), GFP_NOWAIT);
+	if (!sdesc)
+		return NULL;
+
+	for_each_sg(sgl, sg, sglen, i) {
+		len = sg_dma_len(sg);
+
+		if (dir == DMA_MEM_TO_DEV) {
+			src = sg_dma_address(sg);
+			dst = slave_cfg->cfg.dst_addr;
+			src_step = sprd_dma_get_step(slave_cfg->cfg.src_addr_width);
+			dst_step = SPRD_DMA_NONE_STEP;
+		} else {
+			src = slave_cfg->cfg.src_addr;
+			dst = sg_dma_address(sg);
+			src_step = SPRD_DMA_NONE_STEP;
+			dst_step = sprd_dma_get_step(slave_cfg->cfg.dst_addr_width);
+		}
+	}
+
+	sprd_dma_fill_config(slave_cfg, src_step, dst_step, len, flags);
+
+	ret = sprd_dma_config(chan, sdesc, src, dst, slave_cfg);
+	if (ret) {
+		kfree(sdesc);
+		return NULL;
+	}
+
+	return vchan_tx_prep(&schan->vc, &sdesc->vd, flags);
+}
+
+static int sprd_dma_slave_config(struct dma_chan *chan,
+				 struct dma_slave_config *config)
+{
+	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
+	struct sprd_dma_config *slave_cfg = &schan->slave_cfg;
+
+	if (!is_slave_direction(config->direction))
+		return -EINVAL;
+
+	memset(slave_cfg, 0, sizeof(*slave_cfg));
+	memcpy(&slave_cfg->cfg, config, sizeof(*config));
+
+	return 0;
+}
+
 static int sprd_dma_pause(struct dma_chan *chan)
 {
 	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
@@ -733,6 +944,8 @@ static int sprd_dma_probe(struct platform_device *pdev)
 	sdev->dma_dev.device_tx_status = sprd_dma_tx_status;
 	sdev->dma_dev.device_issue_pending = sprd_dma_issue_pending;
 	sdev->dma_dev.device_prep_dma_memcpy = sprd_dma_prep_dma_memcpy;
+	sdev->dma_dev.device_prep_slave_sg = sprd_dma_prep_slave_sg;
+	sdev->dma_dev.device_config = sprd_dma_slave_config;
 	sdev->dma_dev.device_pause = sprd_dma_pause;
 	sdev->dma_dev.device_resume = sprd_dma_resume;
 	sdev->dma_dev.device_terminate_all = sprd_dma_terminate_all;
diff --git a/include/linux/dma/sprd-dma.h b/include/linux/dma/sprd-dma.h
index c545162..b0115e3 100644
--- a/include/linux/dma/sprd-dma.h
+++ b/include/linux/dma/sprd-dma.h
@@ -3,6 +3,10 @@
 #ifndef _SPRD_DMA_H_
 #define _SPRD_DMA_H_
 
+#define SPRD_DMA_REQ_SHIFT 16
+#define SPRD_DMA_FLAGS(req_mode, int_type) \
+	((req_mode) << SPRD_DMA_REQ_SHIFT | (int_type))
+
 /*
  * enum sprd_dma_req_mode: define the DMA request mode
  * @SPRD_DMA_FRAG_REQ: fragment request mode
-- 
1.7.9.5