target/linux/ipq40xx/patches-5.15/302-arm-compressed-set-ipq40xx-watchdog-to-allow-boot.patch

   1 From 11d6a6128a5a07c429941afc202b6e62a19771be Mon Sep 17 00:00:00 2001
   2 From: John Thomson <git@johnthomson.fastmail.com.au>
   3 Date: Fri, 23 Oct 2020 19:42:36 +1000
   4 Subject: [PATCH 2/2] arm: compressed: set ipq40xx watchdog to allow boot
   5
   6 For IPQ40XX systems where the SoC watchdog is activated before linux,
   7 the watchdog timer may be too small for linux to finish uncompress,
   8 boot, and watchdog management start.
   9 If the watchdog is enabled, set the timeout for it to 30 seconds.
  10 The functionality and offsets were copied from:
  11 drivers/watchdog/qcom-wdt.c qcom_wdt_set_timeout & qcom_wdt_start
  12 The watchdog memory address was taken from:
  13 arch/arm/boot/dts/qcom-ipq4019.dtsi
  14
  15 This was required on Mikrotik IPQ40XX consumer hardware using Mikrotik's
  16 RouterBoot bootloader.
  17
  18 Signed-off-by: John Thomson <git@johnthomson.fastmail.com.au>
  19 ---
  20  arch/arm/boot/compressed/head.S | 35 +++++++++++++++++++++++++++++++++
  21  1 file changed, 35 insertions(+)
  22
  23 --- a/arch/arm/boot/compressed/head.S
  24 +++ b/arch/arm/boot/compressed/head.S
  25 @@ -624,6 +624,41 @@ not_relocated:     mov     r0, #0
  26                 bic     r4, r4, #1
  27                 blne    cache_on
  28
  29 +/* Set the Qualcom IPQ40xx watchdog timeout to 30 seconds
  30 + * if it is enabled, so that there is time for kernel
  31 + * to decompress, boot, and take over the watchdog.
  32 + * data and functionality from drivers/watchdog/qcom-wdt.c
  33 + * address from arch/arm/boot/dts/qcom-ipq4019.dtsi
  34 + */
  35 +#ifdef CONFIG_ARCH_IPQ40XX
  36 +watchdog_set:
  37 +               /* offsets:
  38 +                * 0x04 reset   (=1 resets countdown)
  39 +                * 0x08 enable  (=0 disables)
  40 +                * 0x0c status  (=1 when SoC was reset by watchdog)
  41 +                * 0x10 bark    (=timeout warning in ticks)
  42 +                * 0x14 bite    (=timeout reset in ticks)
  43 +                * clock rate is 1<<15 hertz
  44 +                */
  45 +               .equ watchdog, 0x0b017000       @Store watchdog base address
  46 +               movw r0, #:lower16:watchdog
  47 +               movt r0, #:upper16:watchdog
  48 +               ldr r1, [r0, #0x08]     @Get enabled?
  49 +               cmp r1, #1              @If not enabled, do not change
  50 +               bne watchdog_finished
  51 +               mov r1, #0
  52 +               str r1, [r0, #0x08]     @Disable the watchdog
  53 +               mov r1, #1
  54 +               str r1, [r0, #0x04]     @Pet the watchdog
  55 +               mov r1, #30             @30 seconds timeout
  56 +               lsl r1, r1, #15         @converted to ticks
  57 +               str r1, [r0, #0x10]     @Set the bark timeout
  58 +               str r1, [r0, #0x14]     @Set the bite timeout
  59 +               mov r1, #1
  60 +               str r1, [r0, #0x08]     @Enable the watchdog
  61 +watchdog_finished:
  62 +#endif /* CONFIG_ARCH_IPQ40XX */
  63 +
  64  /*
  65   * The C runtime environment should now be setup sufficiently.
  66   * Set up some pointers, and start decompressing.