From bf7baee1935c4d485083c3b3c439631ae4ac3c0f Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Wed, 22 Jul 2020 17:59:31 +0100
Subject: [PATCH] bcm2835-dma: Advertise the full DMA range

Unless the DMA mask is set wider than 32 bits, DMA mapping will use a
bounce buffer.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
 drivers/dma/bcm2835-dma.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -41,6 +41,7 @@
 #define BCM2711_DMA_MEMCPY_CHAN 14
 
 struct bcm2835_dma_cfg_data {
+	u64	dma_mask;
 	u32	chan_40bit_mask;
 };
 
@@ -302,10 +303,12 @@ DEFINE_SPINLOCK(memcpy_lock);
 
 static const struct bcm2835_dma_cfg_data bcm2835_dma_cfg = {
 	.chan_40bit_mask = 0,
+	.dma_mask = DMA_BIT_MASK(32),
 };
 
 static const struct bcm2835_dma_cfg_data bcm2711_dma_cfg = {
 	.chan_40bit_mask = BIT(11) | BIT(12) | BIT(13) | BIT(14),
+	.dma_mask = DMA_BIT_MASK(36),
 };
 
 static inline size_t bcm2835_dma_max_frame_length(struct bcm2835_chan *c)
@@ -1185,6 +1188,8 @@ static struct dma_chan *bcm2835_dma_xlat
 
 static int bcm2835_dma_probe(struct platform_device *pdev)
 {
+	const struct bcm2835_dma_cfg_data *cfg_data;
+	const struct of_device_id *of_id;
 	struct bcm2835_dmadev *od;
 	struct resource *res;
 	void __iomem *base;
@@ -1194,13 +1199,20 @@ static int bcm2835_dma_probe(struct plat
 	int irq_flags;
 	uint32_t chans_available;
 	char chan_name[BCM2835_DMA_CHAN_NAME_SIZE];
-	const struct of_device_id *of_id;
 	int chan_count, chan_start, chan_end;
 
+	of_id = of_match_node(bcm2835_dma_of_match, pdev->dev.of_node);
+	if (!of_id) {
+		dev_err(&pdev->dev, "Failed to match compatible string\n");
+		return -EINVAL;
+	}
+
+	cfg_data = of_id->data;
+
 	if (!pdev->dev.dma_mask)
 		pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
 
-	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+	rc = dma_set_mask_and_coherent(&pdev->dev, cfg_data->dma_mask);
 	if (rc) {
 		dev_err(&pdev->dev, "Unable to set DMA mask\n");
 		return rc;
@@ -1266,7 +1278,7 @@ static int bcm2835_dma_probe(struct plat
 		return -EINVAL;
 	}
 
-	od->cfg_data = of_id->data;
+	od->cfg_data = cfg_data;
 
 	/* Request DMA channel mask from device tree */
 	if (of_property_read_u32(pdev->dev.of_node,
