openwrt/target/linux/bcm27xx/patches-6.1/950-0710-bcm2835-dma-Derive-slave-DMA-addresses-correctly.patch

From 6d317d92627736a94e6c1c4b49c3f63cc33c28aa Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Thu, 11 May 2023 10:00:01 +0100
Subject: [PATCH] bcm2835-dma: Derive slave DMA addresses correctly

Slave addresses for DMA are meant to be supplied as physical addresses
(contrary to what struct snd_dmaengine_dai_dma_data does). It is up to
the DMA controller driver to perform the translation based on its own
view of the world, as described in Device Tree.

Now that the Pi Device Trees have the correct peripheral mappings,
replace the hacky address munging with phys_to_dma().

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
 drivers/dma/bcm2835-dma.c | 23 +++++------------------
 1 file changed, 5 insertions(+), 18 deletions(-)

--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -18,6 +18,7 @@
  *	Copyright 2012 Marvell International Ltd.
  */
 #include <linux/dmaengine.h>
+#include <linux/dma-direct.h>
 #include <linux/dma-mapping.h>
 #include <linux/dmapool.h>
 #include <linux/err.h>
@@ -910,22 +911,12 @@ static struct dma_async_tx_descriptor *b
 	if (direction == DMA_DEV_TO_MEM) {
 		if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
 			return NULL;
-		src = c->cfg.src_addr;
-		/*
-		 * One would think it ought to be possible to get the physical
-		 * to dma address mapping information from the dma-ranges DT
-		 * property, but I've not found a way yet that doesn't involve
-		 * open-coding the whole thing.
-		 */
-		if (c->is_40bit_channel)
-		    src |= 0x400000000ull;
+		src = phys_to_dma(chan->device->dev, c->cfg.src_addr);
 		info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC;
 	} else {
 		if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
 			return NULL;
-		dst = c->cfg.dst_addr;
-		if (c->is_40bit_channel)
-		    dst |= 0x400000000ull;
+		dst = phys_to_dma(chan->device->dev, c->cfg.dst_addr);
 		info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC;
 	}
 
@@ -994,17 +985,13 @@ static struct dma_async_tx_descriptor *b
 	if (direction == DMA_DEV_TO_MEM) {
 		if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
 			return NULL;
-		src = c->cfg.src_addr;
-		if (c->is_40bit_channel)
-		    src |= 0x400000000ull;
+		src = phys_to_dma(chan->device->dev, c->cfg.src_addr);
 		dst = buf_addr;
 		info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC;
 	} else {
 		if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
 			return NULL;
-		dst = c->cfg.dst_addr;
-		if (c->is_40bit_channel)
-		    dst |= 0x400000000ull;
+		dst = phys_to_dma(chan->device->dev, c->cfg.dst_addr);
 		src = buf_addr;
 		info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC;