[PATCH 6/8] dmaengine: tegra: Use iommu-map for stream ID

[Akhil R]

Use iommu-map, when provided, to get the stream ID to be programmed
for each channel. Register each channel separately for allowing it
to use a separate IOMMU domain for the transfer.

Channels will continue to use the same global stream ID if iommu-map
property is not present in the device tree.

Signed-off-by: Akhil R <akhilrajeev@xxxxxxxxxx>
---
 drivers/dma/tegra186-gpc-dma.c | 62 +++++++++++++++++++++++++++-------
 1 file changed, 49 insertions(+), 13 deletions(-)

diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-dma.c
index ce3b1dd52bb3..b8ca269fa3ba 100644
--- a/drivers/dma/tegra186-gpc-dma.c
+++ b/drivers/dma/tegra186-gpc-dma.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_dma.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/reset.h>
 #include <linux/slab.h>
@@ -1403,9 +1404,12 @@ static int tegra_dma_program_sid(struct tegra_dma_channel *tdc, int stream_id)
 static int tegra_dma_probe(struct platform_device *pdev)
 {
 	const struct tegra_dma_chip_data *cdata = NULL;
+	struct tegra_dma_channel *tdc;
+	struct tegra_dma *tdma;
+	struct dma_chan *chan;
+	bool use_iommu_map = false;
 	unsigned int i;
 	u32 stream_id;
-	struct tegra_dma *tdma;
 	int ret;
 
 	cdata = of_device_get_match_data(&pdev->dev);
@@ -1433,9 +1437,12 @@ static int tegra_dma_probe(struct platform_device *pdev)
 
 	tdma->dma_dev.dev = &pdev->dev;
 
-	if (!tegra_dev_iommu_get_stream_id(&pdev->dev, &stream_id)) {
-		dev_err(&pdev->dev, "Missing iommu stream-id\n");
-		return -EINVAL;
+	use_iommu_map = of_property_present(pdev->dev.of_node, "iommu-map");
+	if (!use_iommu_map) {
+		if (!tegra_dev_iommu_get_stream_id(&pdev->dev, &stream_id)) {
+			dev_err(&pdev->dev, "Missing iommu stream-id\n");
+			return -EINVAL;
+		}
 	}
 
 	ret = device_property_read_u32(&pdev->dev, "dma-channel-mask",
@@ -1449,7 +1456,7 @@ static int tegra_dma_probe(struct platform_device *pdev)
 
 	INIT_LIST_HEAD(&tdma->dma_dev.channels);
 	for (i = 0; i < cdata->nr_channels; i++) {
-		struct tegra_dma_channel *tdc = &tdma->channels[i];
+		tdc = &tdma->channels[i];
 
 		/* Check for channel mask */
 		if (!(tdma->chan_mask & BIT(i)))
@@ -1469,10 +1476,6 @@ static int tegra_dma_probe(struct platform_device *pdev)
 
 		vchan_init(&tdc->vc, &tdma->dma_dev);
 		tdc->vc.desc_free = tegra_dma_desc_free;
-
-		/* program stream-id for this channel */
-		tegra_dma_program_sid(tdc, stream_id);
-		tdc->stream_id = stream_id;
 	}
 
 	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(cdata->addr_bits));
@@ -1517,20 +1520,53 @@ static int tegra_dma_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	list_for_each_entry(chan, &tdma->dma_dev.channels, device_node) {
+		struct device *chdev = &chan->dev->device;
+
+		tdc = to_tegra_dma_chan(chan);
+		if (use_iommu_map) {
+			chdev->coherent_dma_mask = pdev->dev.coherent_dma_mask;
+			chdev->dma_mask = &chdev->coherent_dma_mask;
+			chdev->bus = pdev->dev.bus;
+
+			ret = of_dma_configure_id(chdev, pdev->dev.of_node,
+						  true, &tdc->id);
+			if (ret) {
+				dev_err(chdev, "Failed to configure IOMMU for channel %d: %d\n",
+					tdc->id, ret);
+				goto err_unregister;
+			}
+
+			if (!tegra_dev_iommu_get_stream_id(chdev, &stream_id)) {
+				dev_err(chdev, "Failed to get stream ID for channel %d\n",
+					tdc->id);
+				goto err_unregister;
+			}
+
+			chan->dev->chan_dma_dev = true;
+		}
+
+		/* program stream-id for this channel */
+		tegra_dma_program_sid(tdc, stream_id);
+		tdc->stream_id = stream_id;
+	}
+
 	ret = of_dma_controller_register(pdev->dev.of_node,
 					 tegra_dma_of_xlate, tdma);
 	if (ret < 0) {
 		dev_err_probe(&pdev->dev, ret,
 			      "GPC DMA OF registration failed\n");
-
-		dma_async_device_unregister(&tdma->dma_dev);
-		return ret;
+		goto err_unregister;
 	}
 
-	dev_info(&pdev->dev, "GPC DMA driver register %lu channels\n",
+	dev_info(&pdev->dev, "GPC DMA driver registered %lu channels\n",
 		 hweight_long(tdma->chan_mask));
 
 	return 0;
+
+err_unregister:
+	dma_async_device_unregister(&tdma->dma_dev);
+	return ret;
 }
 
 static void tegra_dma_remove(struct platform_device *pdev)
-- 
2.50.1