[PATCH v5 06/16] dmaengine: dw-axi-dmac: Support device_prep_slave_sg

[Sia Jee Heng]

Add device_prep_slave_sg() callback function so that DMA_MEM_TO_DEV
and DMA_DEV_TO_MEM operations in single mode can be supported.

Existing AxiDMA driver only support data transfer between
memory to memory. Data transfer between device to memory and
memory to device in single mode would failed if this interface
is not supported by the AxiDMA driver.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Sia Jee Heng <jee.heng.sia@xxxxxxxxx>
---
 .../dma/dw-axi-dmac/dw-axi-dmac-platform.c    | 154 ++++++++++++++++++
 drivers/dma/dw-axi-dmac/dw-axi-dmac.h         |   1 +
 2 files changed, 155 insertions(+)

diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
index 16e6934ae9a1..1674dcb6fc5b 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
@@ -307,6 +307,22 @@ static void axi_chan_block_xfer_start(struct axi_dma_chan *chan,
 	       priority << CH_CFG_H_PRIORITY_POS |
 	       DWAXIDMAC_HS_SEL_HW << CH_CFG_H_HS_SEL_DST_POS |
 	       DWAXIDMAC_HS_SEL_HW << CH_CFG_H_HS_SEL_SRC_POS);
+	switch (chan->direction) {
+	case DMA_MEM_TO_DEV:
+		reg |= (chan->config.device_fc ?
+			DWAXIDMAC_TT_FC_MEM_TO_PER_DST :
+			DWAXIDMAC_TT_FC_MEM_TO_PER_DMAC)
+			<< CH_CFG_H_TT_FC_POS;
+		break;
+	case DMA_DEV_TO_MEM:
+		reg |= (chan->config.device_fc ?
+			DWAXIDMAC_TT_FC_PER_TO_MEM_SRC :
+			DWAXIDMAC_TT_FC_PER_TO_MEM_DMAC)
+			<< CH_CFG_H_TT_FC_POS;
+		break;
+	default:
+		break;
+	}
 	axi_chan_iowrite32(chan, CH_CFG_H, reg);
 
 	write_chan_llp(chan, first->hw_desc[0].llp | lms);
@@ -454,6 +470,141 @@ static void set_desc_dest_master(struct axi_dma_hw_desc *hw_desc,
 	hw_desc->lli->ctl_lo = cpu_to_le32(val);
 }
 
+static int dw_axi_dma_set_hw_desc(struct axi_dma_chan *chan,
+				  struct axi_dma_hw_desc *hw_desc,
+				  dma_addr_t mem_addr, size_t len)
+{
+	unsigned int data_width = BIT(chan->chip->dw->hdata->m_data_width);
+	unsigned int reg_width;
+	unsigned int mem_width;
+	dma_addr_t device_addr;
+	size_t axi_block_ts;
+	size_t block_ts;
+	u32 ctllo, ctlhi;
+	u32 burst_len;
+
+	axi_block_ts = chan->chip->dw->hdata->block_size[chan->id];
+
+	mem_width = __ffs(data_width | mem_addr | len);
+	if (mem_width > DWAXIDMAC_TRANS_WIDTH_32)
+		mem_width = DWAXIDMAC_TRANS_WIDTH_32;
+
+	switch (chan->direction) {
+	case DMA_MEM_TO_DEV:
+		reg_width = __ffs(chan->config.dst_addr_width);
+		device_addr = chan->config.dst_addr;
+		ctllo = reg_width << CH_CTL_L_DST_WIDTH_POS |
+			mem_width << CH_CTL_L_SRC_WIDTH_POS |
+			DWAXIDMAC_CH_CTL_L_NOINC << CH_CTL_L_DST_INC_POS |
+			DWAXIDMAC_CH_CTL_L_INC << CH_CTL_L_SRC_INC_POS;
+		block_ts = len >> mem_width;
+		break;
+	case DMA_DEV_TO_MEM:
+		reg_width = __ffs(chan->config.src_addr_width);
+		device_addr = chan->config.src_addr;
+		ctllo = reg_width << CH_CTL_L_SRC_WIDTH_POS |
+			mem_width << CH_CTL_L_DST_WIDTH_POS |
+			DWAXIDMAC_CH_CTL_L_INC << CH_CTL_L_DST_INC_POS |
+			DWAXIDMAC_CH_CTL_L_NOINC << CH_CTL_L_SRC_INC_POS;
+		block_ts = len >> reg_width;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (block_ts > axi_block_ts)
+		return -EINVAL;
+
+	hw_desc->lli = axi_desc_get(chan, &hw_desc->llp);
+	if (unlikely(!hw_desc->lli))
+		return -ENOMEM;
+
+	ctlhi = CH_CTL_H_LLI_VALID;
+
+	if (chan->chip->dw->hdata->restrict_axi_burst_len) {
+		burst_len = chan->chip->dw->hdata->axi_rw_burst_len;
+		ctlhi |= CH_CTL_H_ARLEN_EN | CH_CTL_H_AWLEN_EN |
+			 burst_len << CH_CTL_H_ARLEN_POS |
+			 burst_len << CH_CTL_H_AWLEN_POS;
+	}
+
+	hw_desc->lli->ctl_hi = cpu_to_le32(ctlhi);
+
+	if (chan->direction == DMA_MEM_TO_DEV) {
+		write_desc_sar(hw_desc, mem_addr);
+		write_desc_dar(hw_desc, device_addr);
+	} else {
+		write_desc_sar(hw_desc, device_addr);
+		write_desc_dar(hw_desc, mem_addr);
+	}
+
+	hw_desc->lli->block_ts_lo = cpu_to_le32(block_ts - 1);
+
+	ctllo |= DWAXIDMAC_BURST_TRANS_LEN_4 << CH_CTL_L_DST_MSIZE_POS |
+		 DWAXIDMAC_BURST_TRANS_LEN_4 << CH_CTL_L_SRC_MSIZE_POS;
+	hw_desc->lli->ctl_lo = cpu_to_le32(ctllo);
+
+	set_desc_src_master(hw_desc);
+
+	return 0;
+}
+
+static struct dma_async_tx_descriptor *
+dw_axi_dma_chan_prep_slave_sg(struct dma_chan *dchan, struct scatterlist *sgl,
+			      unsigned int sg_len,
+			      enum dma_transfer_direction direction,
+			      unsigned long flags, void *context)
+{
+	struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
+	struct axi_dma_hw_desc *hw_desc = NULL;
+	struct axi_dma_desc *desc = NULL;
+	struct scatterlist *sg;
+	unsigned int i;
+	u32 mem, len;
+	int status;
+	u64 llp = 0;
+	u8 lms = 0; /* Select AXI0 master for LLI fetching */
+
+	if (unlikely(!is_slave_direction(direction) || !sg_len))
+		return NULL;
+
+	chan->direction = direction;
+
+	desc = axi_desc_alloc(sg_len);
+	if (unlikely(!desc))
+		goto err_desc_get;
+
+	desc->chan = chan;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		mem = sg_dma_address(sg);
+		len = sg_dma_len(sg);
+		hw_desc = &desc->hw_desc[i];
+
+		status = dw_axi_dma_set_hw_desc(chan, hw_desc, mem, len);
+		if (status < 0)
+			goto err_desc_get;
+	}
+
+	/* Set end-of-link to the last link descriptor of list */
+	set_desc_last(&desc->hw_desc[sg_len - 1]);
+
+	/* Managed transfer list */
+	do {
+		hw_desc = &desc->hw_desc[--sg_len];
+		write_desc_llp(hw_desc, llp | lms);
+		llp = hw_desc->llp;
+	} while (sg_len);
+
+	return vchan_tx_prep(&chan->vc, &desc->vd, flags);
+
+err_desc_get:
+	if (desc)
+		axi_desc_put(desc);
+
+	return NULL;
+}
+
 static struct dma_async_tx_descriptor *
 dma_chan_prep_dma_memcpy(struct dma_chan *dchan, dma_addr_t dst_adr,
 			 dma_addr_t src_adr, size_t len, unsigned long flags)
@@ -938,12 +1089,14 @@ static int dw_probe(struct platform_device *pdev)
 
 	/* Set capabilities */
 	dma_cap_set(DMA_MEMCPY, dw->dma.cap_mask);
+	dma_cap_set(DMA_SLAVE, dw->dma.cap_mask);
 
 	/* DMA capabilities */
 	dw->dma.chancnt = hdata->nr_channels;
 	dw->dma.src_addr_widths = AXI_DMA_BUSWIDTHS;
 	dw->dma.dst_addr_widths = AXI_DMA_BUSWIDTHS;
 	dw->dma.directions = BIT(DMA_MEM_TO_MEM);
+	dw->dma.directions |= BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM);
 	dw->dma.residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
 
 	dw->dma.dev = chip->dev;
@@ -959,6 +1112,7 @@ static int dw_probe(struct platform_device *pdev)
 	dw->dma.device_prep_dma_memcpy = dma_chan_prep_dma_memcpy;
 	dw->dma.device_synchronize = dw_axi_dma_synchronize;
 	dw->dma.device_config = dw_axi_dma_chan_slave_config;
+	dw->dma.device_prep_slave_sg = dw_axi_dma_chan_prep_slave_sg;
 
 	platform_set_drvdata(pdev, chip);
 
diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
index a75b921d6b1a..ac49f2e14b0c 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
@@ -44,6 +44,7 @@ struct axi_dma_chan {
 
 	struct axi_dma_desc		*desc;
 	struct dma_slave_config		config;
+	enum dma_transfer_direction	direction;
 	/* these other elements are all protected by vc.lock */
 	bool				is_paused;
 };
-- 
2.18.0