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

   1 From 6d317d92627736a94e6c1c4b49c3f63cc33c28aa Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Thu, 11 May 2023 10:00:01 +0100
   4 Subject: [PATCH] bcm2835-dma: Derive slave DMA addresses correctly
   5
   6 Slave addresses for DMA are meant to be supplied as physical addresses
   7 (contrary to what struct snd_dmaengine_dai_dma_data does). It is up to
   8 the DMA controller driver to perform the translation based on its own
   9 view of the world, as described in Device Tree.
  10
  11 Now that the Pi Device Trees have the correct peripheral mappings,
  12 replace the hacky address munging with phys_to_dma().
  13
  14 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  15 ---
  16  drivers/dma/bcm2835-dma.c | 23 +++++------------------
  17  1 file changed, 5 insertions(+), 18 deletions(-)
  18
  19 --- a/drivers/dma/bcm2835-dma.c
  20 +++ b/drivers/dma/bcm2835-dma.c
  21 @@ -18,6 +18,7 @@
  22   *     Copyright 2012 Marvell International Ltd.
  23   */
  24  #include <linux/dmaengine.h>
  25 +#include <linux/dma-direct.h>
  26  #include <linux/dma-mapping.h>
  27  #include <linux/dmapool.h>
  28  #include <linux/err.h>
  29 @@ -910,22 +911,12 @@ static struct dma_async_tx_descriptor *b
  30         if (direction == DMA_DEV_TO_MEM) {
  31                 if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
  32                         return NULL;
  33 -               src = c->cfg.src_addr;
  34 -               /*
  35 -                * One would think it ought to be possible to get the physical
  36 -                * to dma address mapping information from the dma-ranges DT
  37 -                * property, but I've not found a way yet that doesn't involve
  38 -                * open-coding the whole thing.
  39 -                */
  40 -               if (c->is_40bit_channel)
  41 -                   src |= 0x400000000ull;
  42 +               src = phys_to_dma(chan->device->dev, c->cfg.src_addr);
  43                 info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC;
  44         } else {
  45                 if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
  46                         return NULL;
  47 -               dst = c->cfg.dst_addr;
  48 -               if (c->is_40bit_channel)
  49 -                   dst |= 0x400000000ull;
  50 +               dst = phys_to_dma(chan->device->dev, c->cfg.dst_addr);
  51                 info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC;
  52         }
  53
  54 @@ -994,17 +985,13 @@ static struct dma_async_tx_descriptor *b
  55         if (direction == DMA_DEV_TO_MEM) {
  56                 if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
  57                         return NULL;
  58 -               src = c->cfg.src_addr;
  59 -               if (c->is_40bit_channel)
  60 -                   src |= 0x400000000ull;
  61 +               src = phys_to_dma(chan->device->dev, c->cfg.src_addr);
  62                 dst = buf_addr;
  63                 info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC;
  64         } else {
  65                 if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
  66                         return NULL;
  67 -               dst = c->cfg.dst_addr;
  68 -               if (c->is_40bit_channel)
  69 -                   dst |= 0x400000000ull;
  70 +               dst = phys_to_dma(chan->device->dev, c->cfg.dst_addr);
  71                 src = buf_addr;
  72                 info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC;
  73