openwrt/target/linux/brcm2708/patches-4.4/0014-bcm2835-i2s-get-base-address-for-DMA-from-devicetree.patch

From 17025015a60ffc92d09ade98131ed080bbf09106 Mon Sep 17 00:00:00 2001
From: Matthias Reichl <hias@horus.com>
Date: Sun, 11 Oct 2015 16:44:05 +0200
Subject: [PATCH] bcm2835-i2s: get base address for DMA from devicetree

Code copied from spi-bcm2835. Get physical address from devicetree
instead of using hardcoded constant.

Signed-off-by: Matthias Reichl <hias@horus.com>
---
 sound/soc/bcm/bcm2835-i2s.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

--- a/sound/soc/bcm/bcm2835-i2s.c
+++ b/sound/soc/bcm/bcm2835-i2s.c
@@ -38,6 +38,7 @@
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/clk.h>
+#include <linux/of_address.h>
 
 #include <sound/core.h>
 #include <sound/pcm.h>
@@ -158,10 +159,6 @@ static const unsigned int bcm2835_clk_fr
 #define BCM2835_I2S_INT_RXR		BIT(1)
 #define BCM2835_I2S_INT_TXW		BIT(0)
 
-/* I2S DMA interface */
-/* FIXME: Needs IOMMU support */
-#define BCM2835_VCMMU_SHIFT		(0x7E000000 - 0x20000000)
-
 /* General device struct */
 struct bcm2835_i2s_dev {
 	struct device				*dev;
@@ -791,6 +788,15 @@ static int bcm2835_i2s_probe(struct plat
 	int ret;
 	struct regmap *regmap[2];
 	struct resource *mem[2];
+	const __be32 *addr;
+	dma_addr_t dma_reg_base;
+
+	addr = of_get_address(pdev->dev.of_node, 0, NULL, NULL);
+	if (!addr) {
+		dev_err(&pdev->dev, "could not get DMA-register address\n");
+		return -ENODEV;
+	}
+	dma_reg_base = be32_to_cpup(addr);
 
 	/* Request both ioareas */
 	for (i = 0; i <= 1; i++) {
@@ -817,12 +823,10 @@ static int bcm2835_i2s_probe(struct plat
 
 	/* Set the DMA address */
 	dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].addr =
-		(dma_addr_t)mem[0]->start + BCM2835_I2S_FIFO_A_REG
-					  + BCM2835_VCMMU_SHIFT;
+		dma_reg_base + BCM2835_I2S_FIFO_A_REG;
 
 	dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].addr =
-		(dma_addr_t)mem[0]->start + BCM2835_I2S_FIFO_A_REG
-					  + BCM2835_VCMMU_SHIFT;
+		dma_reg_base + BCM2835_I2S_FIFO_A_REG;
 
 	/* Set the bus width */
 	dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].addr_width =