1 files changed, 56 insertions, 19 deletions

diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 9c41a4e42575..f06016d38a05 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -192,6 +192,7 @@ struct rcar_dmac_chan {
  * @iomem: remapped I/O memory base
  * @n_channels: number of available channels
  * @channels: array of DMAC channels
+ * @channels_mask: bitfield of which DMA channels are managed by this driver
  * @modules: bitmask of client modules in use
  */
 struct rcar_dmac {
@@ -202,18 +203,27 @@ struct rcar_dmac {
 
 	unsigned int n_channels;
 	struct rcar_dmac_chan *channels;
+	u32 channels_mask;
 
 	DECLARE_BITMAP(modules, 256);
 };
 
 #define to_rcar_dmac(d)		container_of(d, struct rcar_dmac, engine)
 
+/*
+ * struct rcar_dmac_of_data - This driver's OF data
+ * @chan_offset_base: DMAC channels base offset
+ * @chan_offset_stride: DMAC channels offset stride
+ */
+struct rcar_dmac_of_data {
+	u32 chan_offset_base;
+	u32 chan_offset_stride;
+};
+
 /* -----------------------------------------------------------------------------
  * Registers
  */
 
-#define RCAR_DMAC_CHAN_OFFSET(i)	(0x8000 + 0x80 * (i))
-
 #define RCAR_DMAISTA			0x0020
 #define RCAR_DMASEC			0x0030
 #define RCAR_DMAOR			0x0060
@@ -438,7 +448,7 @@ static int rcar_dmac_init(struct rcar_dmac *dmac)
 	u16 dmaor;
 
 	/* Clear all channels and enable the DMAC globally. */
-	rcar_dmac_write(dmac, RCAR_DMACHCLR, GENMASK(dmac->n_channels - 1, 0));
+	rcar_dmac_write(dmac, RCAR_DMACHCLR, dmac->channels_mask);
 	rcar_dmac_write(dmac, RCAR_DMAOR,
 			RCAR_DMAOR_PRI_FIXED | RCAR_DMAOR_DME);
 
@@ -814,6 +824,9 @@ static void rcar_dmac_stop_all_chan(struct rcar_dmac *dmac)
 	for (i = 0; i < dmac->n_channels; ++i) {
 		struct rcar_dmac_chan *chan = &dmac->channels[i];
 
+		if (!(dmac->channels_mask & BIT(i)))
+			continue;
+
 		/* Stop and reinitialize the channel. */
 		spin_lock_irq(&chan->lock);
 		rcar_dmac_chan_halt(chan);
@@ -1721,6 +1734,7 @@ static const struct dev_pm_ops rcar_dmac_pm = {
 
 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 platform_device *pdev = to_platform_device(dmac->dev);
@@ -1730,7 +1744,8 @@ static int rcar_dmac_chan_probe(struct rcar_dmac *dmac,
 	int ret;
 
 	rchan->index = index;
-	rchan->iomem = dmac->iomem + RCAR_DMAC_CHAN_OFFSET(index);
+	rchan->iomem = dmac->iomem + data->chan_offset_base +
+		       data->chan_offset_stride * index;
 	rchan->mid_rid = -EINVAL;
 
 	spin_lock_init(&rchan->lock);
@@ -1744,10 +1759,8 @@ static int rcar_dmac_chan_probe(struct rcar_dmac *dmac,
 	/* Request the channel interrupt. */
 	sprintf(pdev_irqname, "ch%u", index);
 	rchan->irq = platform_get_irq_byname(pdev, pdev_irqname);
-	if (rchan->irq < 0) {
-		dev_err(dmac->dev, "no IRQ specified for channel %u\n", index);
+	if (rchan->irq < 0)
 		return -ENODEV;
-	}
 
 	irqname = devm_kasprintf(dmac->dev, GFP_KERNEL, "%s:%u",
 				 dev_name(dmac->dev), index);
@@ -1776,6 +1789,8 @@ static int rcar_dmac_chan_probe(struct rcar_dmac *dmac,
 	return 0;
 }
 
+#define RCAR_DMAC_MAX_CHANNELS	32
+
 static int rcar_dmac_parse_of(struct device *dev, struct rcar_dmac *dmac)
 {
 	struct device_node *np = dev->of_node;
@@ -1787,12 +1802,24 @@ static int rcar_dmac_parse_of(struct device *dev, struct rcar_dmac *dmac)
 		return ret;
 	}
 
-	if (dmac->n_channels <= 0 || dmac->n_channels >= 100) {
+	/* The hardware and driver don't support more than 32 bits in CHCLR */
+	if (dmac->n_channels <= 0 ||
+	    dmac->n_channels >= RCAR_DMAC_MAX_CHANNELS) {
 		dev_err(dev, "invalid number of channels %u\n",
 			dmac->n_channels);
 		return -EINVAL;
 	}
 
+	/*
+	 * If the driver is unable to read dma-channel-mask property,
+	 * the driver assumes that it can use all channels.
+	 */
+	dmac->channels_mask = GENMASK(dmac->n_channels - 1, 0);
+	of_property_read_u32(np, "dma-channel-mask", &dmac->channels_mask);
+
+	/* If the property has out-of-channel mask, this driver clears it */
+	dmac->channels_mask &= GENMASK(dmac->n_channels - 1, 0);
+
 	return 0;
 }
 
@@ -1802,13 +1829,16 @@ static int rcar_dmac_probe(struct platform_device *pdev)
 		DMA_SLAVE_BUSWIDTH_2_BYTES | DMA_SLAVE_BUSWIDTH_4_BYTES |
 		DMA_SLAVE_BUSWIDTH_8_BYTES | DMA_SLAVE_BUSWIDTH_16_BYTES |
 		DMA_SLAVE_BUSWIDTH_32_BYTES | DMA_SLAVE_BUSWIDTH_64_BYTES;
-	unsigned int channels_offset = 0;
 	struct dma_device *engine;
 	struct rcar_dmac *dmac;
-	struct resource *mem;
+	const struct rcar_dmac_of_data *data;
 	unsigned int i;
 	int ret;
 
+	data = of_device_get_match_data(&pdev->dev);
+	if (!data)
+		return -EINVAL;
+
 	dmac = devm_kzalloc(&pdev->dev, sizeof(*dmac), GFP_KERNEL);
 	if (!dmac)
 		return -ENOMEM;
@@ -1831,10 +1861,8 @@ static int rcar_dmac_probe(struct platform_device *pdev)
 	 * level we can't disable it selectively, so ignore channel 0 for now if
 	 * the device is part of an IOMMU group.
 	 */
-	if (device_iommu_mapped(&pdev->dev)) {
-		dmac->n_channels--;
-		channels_offset = 1;
-	}
+	if (device_iommu_mapped(&pdev->dev))
+		dmac->channels_mask &= ~BIT(0);
 
 	dmac->channels = devm_kcalloc(&pdev->dev, dmac->n_channels,
 				      sizeof(*dmac->channels), GFP_KERNEL);
@@ -1842,8 +1870,7 @@ static int rcar_dmac_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	/* Request resources. */
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	dmac->iomem = devm_ioremap_resource(&pdev->dev, mem);
+	dmac->iomem = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(dmac->iomem))
 		return PTR_ERR(dmac->iomem);
 
@@ -1892,8 +1919,10 @@ static int rcar_dmac_probe(struct platform_device *pdev)
 	INIT_LIST_HEAD(&engine->channels);
 
 	for (i = 0; i < dmac->n_channels; ++i) {
-		ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i],
-					   i + channels_offset);
+		if (!(dmac->channels_mask & BIT(i)))
+			continue;
+
+		ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i], data, i);
 		if (ret < 0)
 			goto error;
 	}
@@ -1940,8 +1969,16 @@ static void rcar_dmac_shutdown(struct platform_device *pdev)
 	rcar_dmac_stop_all_chan(dmac);
 }
 
+static const struct rcar_dmac_of_data rcar_dmac_data = {
+	.chan_offset_base = 0x8000,
+	.chan_offset_stride = 0x80,
+};
+
 static const struct of_device_id rcar_dmac_of_ids[] = {
-	{ .compatible = "renesas,rcar-dmac", },
+	{
+		.compatible = "renesas,rcar-dmac",
+		.data = &rcar_dmac_data,
+	},
 	{ /* Sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, rcar_dmac_of_ids);