target/linux/bcm27xx/patches-5.4/950-0438-ARM-dts-bcm2711-fix-soc-s-node-dma-ranges.patch

   1 From 44d7ee4730fbe3c00aba0457489acd0b6e2937c9 Mon Sep 17 00:00:00 2001
   2 From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
   3 Date: Wed, 4 Dec 2019 13:56:33 +0100
   4 Subject: [PATCH] ARM: dts: bcm2711: fix soc's node dma-ranges
   5
   6 Raspberry Pi's firmware has a feature to select how much memory to
   7 reserve for its GPU called 'gpu_mem'. The possible values go from 16MB
   8 to 944MB, with a default of 64MB. This memory resides in the topmost
   9 part of the lower 1GB memory area and grows bigger expanding towards the
  10 begging of memory.
  11
  12 It turns out that with low 'gpu_mem' values (16MB and 32MB) the size of
  13 the memory available to the system in the lower 1GB area can outgrow the
  14 interconnect's dma-range as its size was selected based on the maximum
  15 system memory available given the default gpu_mem configuration. This
  16 makes that memory slice unavailable for DMA. And may cause nasty kernel
  17 warnings if CMA happens to include it.
  18
  19 Change soc's dma-ranges to really reflect it's HW limitation, which is
  20 being able to only DMA to the lower 1GB area.
  21
  22 Fixes: 7dbe8c62ceeb ("ARM: dts: Add minimal Raspberry Pi 4 support")
  23 Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
  24 Reviewed-by: Phil Elwell <phil@raspberrypi.org>
  25 Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
  26 ---
  27  arch/arm/boot/dts/bcm2711.dtsi | 2 +-
  28  1 file changed, 1 insertion(+), 1 deletion(-)
  29
  30 --- a/arch/arm/boot/dts/bcm2711.dtsi
  31 +++ b/arch/arm/boot/dts/bcm2711.dtsi
  32 @@ -43,7 +43,7 @@
  33                          <0x7c000000  0x0 0xfc000000  0x02000000>,
  34                          <0x40000000  0x0 0xff800000  0x00800000>;
  35                 /* Emulate a contiguous 30-bit address range for DMA */
  36 -               dma-ranges = <0xc0000000  0x0 0x00000000  0x3c000000>;
  37 +               dma-ranges = <0xc0000000  0x0 0x00000000  0x40000000>;
  38
  39                 /*
  40                  * This node is the provider for the enable-method for