target/linux/ipq40xx/patches-4.14/082-ARM-dts-ipq4019-Add-TZ-and-SMEM-reserved-regions.patch

   1 From fc566294610fa49e9d8c31c4ecc9c82f49b11f59 Mon Sep 17 00:00:00 2001
   2 From: Sven Eckelmann <sven.eckelmann@openmesh.com>
   3 Date: Wed, 18 Apr 2018 09:10:44 +0200
   4 Subject: [PATCH] ARM: dts: ipq4019: Add TZ and SMEM reserved regions
   5
   6 The QSEE (trustzone) is started on IPQ4019 before Linux is started.
   7 According to QCA, it is placed in in the the memory region
   8 0x87e80000-0x88000000 and must not be accessed directly. There is an
   9 additional memory region 0x87e00000-0x87E80000 smem which which can be used
  10 for communication with the TZ. The driver for the latter is not yet ready
  11 but it is still not allowed to use this memory region like any other
  12 memory region.
  13
  14 Not reserving this memory region either leads to kernel crashes, kernel
  15 hangs (often during the boot) or bus errors for userspace programs. The
  16 latter happens when a program is using a memory region which is mapped to
  17 these physical memory regions.
  18
  19   [  571.758058] Unhandled fault: imprecise external abort (0xc06) at 0x01715ff8
  20   [  571.758099] pgd = cebec000
  21   [  571.763826] [01715ff8] *pgd=8e7fa835, *pte=87e7f75f, *ppte=87e7fc7f
  22   Bus error
  23
  24 Signed-off-by: Sven Eckelmann <sven.eckelmann@openmesh.com>
  25
  26 Forwarded: https://patchwork.kernel.org/patch/10347459/
  27 ---
  28 Cc: Sricharan Ramabadhran <srichara@qti.qualcomm.com>
  29 Cc: Senthilkumar N L <snlakshm@qti.qualcomm.com>
  30
  31 There are additional memory regions which have to be initialized first by
  32 Linux. So they are currently not used. We were told by QCA that the
  33 features QSDK uses them for are:
  34
  35 * crash dump feature
  36   - a couple of regions used when 'qca,scm_restart_reason' dt node has the
  37     value 'dload_status' not set to 1
  38     + apps_bl <0x87000000 0x400000>
  39     + sbl <0x87400000 0x100000>
  40     + cnss_debug <0x87400000 0x100000>
  41     + cpu_context_dump <0x87b00000 0x080000>
  42   - required driver not available in Linux
  43   - safe to remove
  44 * QSEE app execution
  45   - region tz_apps <0x87b80000 0x280000>
  46   - required driver not available in Linux
  47   - safe to remove
  48 * communication with TZ/QSEE
  49   - region smem <0x87b80000 0x280000>
  50   - driver changes not yet upstreamed
  51   - must not be removed because any access can crash kernel/program
  52 * trustzone (QSEE) private memory
  53   - region tz <0x87e80000 0x180000>
  54   - must not be removed because any access can crash kernel/program
  55
  56 The problem with the missing regions was reported in 2016 [1]. So maybe
  57 this change qualifies for a stable@vger.kernel.org submission.
  58
  59 [1] https://www.spinics.net/lists/linux-arm-msm/msg21536.html
  60 ---
  61  arch/arm/boot/dts/qcom-ipq4019.dtsi | 16 ++++++++++++++++
  62  1 file changed, 16 insertions(+)
  63
  64 --- a/arch/arm/boot/dts/qcom-ipq4019.dtsi
  65 +++ b/arch/arm/boot/dts/qcom-ipq4019.dtsi
  66 @@ -23,6 +23,22 @@
  67         compatible = "qcom,ipq4019";
  68         interrupt-parent = <&intc>;
  69
  70 +       reserved-memory {
  71 +               #address-cells = <0x1>;
  72 +               #size-cells = <0x1>;
  73 +               ranges;
  74 +
  75 +               smem_region: smem@87e00000 {
  76 +                       reg = <0x87e00000 0x080000>;
  77 +                       no-map;
  78 +               };
  79 +
  80 +               tz@87e80000 {
  81 +                       reg = <0x87e80000 0x180000>;
  82 +                       no-map;
  83 +               };
  84 +       };
  85 +
  86         aliases {
  87                 spi0 = &blsp1_spi1;
  88                 spi1 = &blsp1_spi2;