dmaengine: rcar-dmac: Add support for R-Car V3U

The DMACs (both SYS-DMAC and RT-DMAC) on R-Car V3U differ slightly from
the DMACs on R-Car Gen2 and other R-Car Gen3 SoCs:
1. The per-channel registers are located in a second register block.
Add support for mapping the second block, using the appropriate
offsets and stride.
2. The common Channel Clear Register (DMACHCLR) was replaced by a
per-channel register.
Update rcar_dmac_chan_clear{,_all}() to handle this.
As rcar_dmac_init() needs to clear the status before the individual
channels are probed, channel index and base address initialization
are moved forward.

Inspired by a patch in the BSP by Phong Hoang
<[e-mail]>.

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Tested-by: Wolfram Sang <[e-mail]>
Tested-by: Yoshihiro Shimoda <[e-mail]>
Reviewed-by: Yoshihiro Shimoda <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/sh/rcar-dmac.c

···
  * struct rcar_dmac - R-Car Gen2 DMA Controller
  * @engine: base DMA engine object
  * @dev: the hardware device
- * @iomem: remapped I/O memory base
+ * @dmac_base: remapped base register block
+ * @chan_base: remapped channel register block (optional)
  * @n_channels: number of available channels
  * @channels: array of DMAC channels
  * @channels_mask: bitfield of which DMA channels are managed by this driver
···
 struct rcar_dmac {
 	struct dma_device engine;
 	struct device *dev;
-	void __iomem *iomem;
+	void __iomem *dmac_base;
+	void __iomem *chan_base;
 
 	unsigned int n_channels;
 	struct rcar_dmac_chan *channels;
···
 #define RCAR_DMAOR_PRI_ROUND_ROBIN	(3 << 8)
 #define RCAR_DMAOR_AE			(1 << 2)
 #define RCAR_DMAOR_DME			(1 << 0)
-#define RCAR_DMACHCLR			0x0080
+#define RCAR_DMACHCLR			0x0080	/* Not on R-Car V3U */
 #define RCAR_DMADPSEC			0x00a0
 
 #define RCAR_DMASAR			0x0000
···
 #define RCAR_DMAFIXDAR			0x0014
 #define RCAR_DMAFIXDPBASE		0x0060
 
+/* For R-Car V3U */
+#define RCAR_V3U_DMACHCLR		0x0100
+
 /* Hardcode the MEMCPY transfer size to 4 bytes. */
 #define RCAR_DMAC_MEMCPY_XFER_SIZE	4
 
···
 static void rcar_dmac_write(struct rcar_dmac *dmac, u32 reg, u32 data)
 {
 	if (reg == RCAR_DMAOR)
-		writew(data, dmac->iomem + reg);
+		writew(data, dmac->dmac_base + reg);
 	else
-		writel(data, dmac->iomem + reg);
+		writel(data, dmac->dmac_base + reg);
 }
 
 static u32 rcar_dmac_read(struct rcar_dmac *dmac, u32 reg)
 {
 	if (reg == RCAR_DMAOR)
-		return readw(dmac->iomem + reg);
+		return readw(dmac->dmac_base + reg);
 	else
-		return readl(dmac->iomem + reg);
+		return readl(dmac->dmac_base + reg);
 }
 
 static u32 rcar_dmac_chan_read(struct rcar_dmac_chan *chan, u32 reg)
···
 static void rcar_dmac_chan_clear(struct rcar_dmac *dmac,
 				 struct rcar_dmac_chan *chan)
 {
-	rcar_dmac_write(dmac, RCAR_DMACHCLR, BIT(chan->index));
+	if (dmac->chan_base)
+		rcar_dmac_chan_write(chan, RCAR_V3U_DMACHCLR, 1);
+	else
+		rcar_dmac_write(dmac, RCAR_DMACHCLR, BIT(chan->index));
 }
 
 static void rcar_dmac_chan_clear_all(struct rcar_dmac *dmac)
 {
-	rcar_dmac_write(dmac, RCAR_DMACHCLR, dmac->channels_mask);
+	struct rcar_dmac_chan *chan;
+	unsigned int i;
+
+	if (dmac->chan_base) {
+		for_each_rcar_dmac_chan(i, dmac, chan)
+			rcar_dmac_chan_write(chan, RCAR_V3U_DMACHCLR, 1);
+	} else {
+		rcar_dmac_write(dmac, RCAR_DMACHCLR, dmac->channels_mask);
+	}
 }
 
 /* -----------------------------------------------------------------------------
···
  */
 
 static int rcar_dmac_chan_probe(struct rcar_dmac *dmac,
-				struct rcar_dmac_chan *rchan,
-				const struct rcar_dmac_of_data *data,
-				unsigned int index)
+				struct rcar_dmac_chan *rchan)
 {
 	struct platform_device *pdev = to_platform_device(dmac->dev);
 	struct dma_chan *chan = &rchan->chan;
···
 	char *irqname;
 	int ret;
 
-	rchan->index = index;
-	rchan->iomem = dmac->iomem + data->chan_offset_base +
-		       data->chan_offset_stride * index;
 	rchan->mid_rid = -EINVAL;
 
 	spin_lock_init(&rchan->lock);
···
 	INIT_LIST_HEAD(&rchan->desc.wait);
 
 	/* Request the channel interrupt. */
-	sprintf(pdev_irqname, "ch%u", index);
+	sprintf(pdev_irqname, "ch%u", rchan->index);
 	rchan->irq = platform_get_irq_byname(pdev, pdev_irqname);
 	if (rchan->irq < 0)
 		return -ENODEV;
 
 	irqname = devm_kasprintf(dmac->dev, GFP_KERNEL, "%s:%u",
-				 dev_name(dmac->dev), index);
+				 dev_name(dmac->dev), rchan->index);
 	if (!irqname)
 		return -ENOMEM;
 
···
 	const struct rcar_dmac_of_data *data;
 	struct rcar_dmac_chan *chan;
 	struct dma_device *engine;
+	void __iomem *chan_base;
 	struct rcar_dmac *dmac;
 	unsigned int i;
 	int ret;
···
 		return -ENOMEM;
 
 	/* Request resources. */
-	dmac->iomem = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(dmac->iomem))
-		return PTR_ERR(dmac->iomem);
+	dmac->dmac_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(dmac->dmac_base))
+		return PTR_ERR(dmac->dmac_base);
+
+	if (!data->chan_offset_base) {
+		dmac->chan_base = devm_platform_ioremap_resource(pdev, 1);
+		if (IS_ERR(dmac->chan_base))
+			return PTR_ERR(dmac->chan_base);
+
+		chan_base = dmac->chan_base;
+	} else {
+		chan_base = dmac->dmac_base + data->chan_offset_base;
+	}
+
+	for_each_rcar_dmac_chan(i, dmac, chan) {
+		chan->index = i;
+		chan->iomem = chan_base + i * data->chan_offset_stride;
+	}
 
 	/* Enable runtime PM and initialize the device. */
 	pm_runtime_enable(&pdev->dev);
···
 	INIT_LIST_HEAD(&engine->channels);
 
 	for_each_rcar_dmac_chan(i, dmac, chan) {
-		ret = rcar_dmac_chan_probe(dmac, chan, data, i);
+		ret = rcar_dmac_chan_probe(dmac, chan);
 		if (ret < 0)
 			goto error;
 	}
···
 }
 
 static const struct rcar_dmac_of_data rcar_dmac_data = {
-	.chan_offset_base = 0x8000,
-	.chan_offset_stride = 0x80,
+	.chan_offset_base	= 0x8000,
+	.chan_offset_stride	= 0x80,
+};
+
+static const struct rcar_dmac_of_data rcar_v3u_dmac_data = {
+	.chan_offset_base	= 0x0,
+	.chan_offset_stride	= 0x1000,
 };
 
 static const struct of_device_id rcar_dmac_of_ids[] = {
 	{
 		.compatible = "renesas,rcar-dmac",
 		.data = &rcar_dmac_data,
+	}, {
+		.compatible = "renesas,dmac-r8a779a0",
+		.data = &rcar_v3u_dmac_data,
 	},
 	{ /* Sentinel */ }
 };