target/linux/bcm27xx/patches-5.4/950-0638-ARM-dts-bcm2711-Restrict-CMA-to-first-768MB.patch

   1 From 7b307016ed13cbb65e08b6a704912e5c9e5b81ac Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Tue, 14 Apr 2020 15:25:02 +0100
   4 Subject: [PATCH] ARM: dts: bcm2711: Restrict CMA to first 768MB
   5
   6 The downstream 32-bit 2711 kernel configuration enables HIGHMEM for
   7 access to more physical RAM. The HIGHMEM zone starts at 0x30000000
   8 (768MB), and allowing the CMA zone to overlap that area causes a
   9 failure during CMA activation.
  10
  11 Avoid the overlap by limiting CMA to the first 768MB. This is overly
  12 restrictive on a 64-bit kernel, but shouldn't cause any practical
  13 problems.
  14
  15 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  16 ---
  17  arch/arm/boot/dts/bcm2711-rpi.dtsi | 5 +++++
  18  1 file changed, 5 insertions(+)
  19
  20 --- a/arch/arm/boot/dts/bcm2711-rpi.dtsi
  21 +++ b/arch/arm/boot/dts/bcm2711-rpi.dtsi
  22 @@ -45,6 +45,11 @@
  23         };
  24  };
  25
  26 +&cma {
  27 +       /* Limit cma to the lower 768MB to allow room for HIGHMEM on 32-bit */
  28 +       alloc-ranges = <0x0 0x00000000 0x30000000>;
  29 +};
  30 +
  31  &soc {
  32         thermal: thermal@7d5d2200 {
  33                 compatible = "brcm,avs-tmon-bcm2711";