target/linux/brcm2708/patches-4.19/950-0017-watchdog-bcm2835-Support-setting-reboot-partition.patch

   1 From 3091f3a65590ab446e9c637377efa55dc3b8996f Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
   3 Date: Fri, 7 Oct 2016 16:50:59 +0200
   4 Subject: [PATCH 017/703] watchdog: bcm2835: Support setting reboot partition
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 The Raspberry Pi firmware looks at the RSTS register to know which
  10 partition to boot from. The reboot syscall command
  11 LINUX_REBOOT_CMD_RESTART2 supports passing in a string argument.
  12
  13 Add support for passing in a partition number 0..63 to boot from.
  14 Partition 63 is a special partiton indicating halt.
  15 If the partition doesn't exist, the firmware falls back to partition 0.
  16
  17 Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
  18 ---
  19  drivers/watchdog/bcm2835_wdt.c | 49 +++++++++++++++++++---------------
  20  1 file changed, 27 insertions(+), 22 deletions(-)
  21
  22 --- a/drivers/watchdog/bcm2835_wdt.c
  23 +++ b/drivers/watchdog/bcm2835_wdt.c
  24 @@ -31,13 +31,7 @@
  25  #define PM_RSTC_WRCFG_SET              0x00000030
  26  #define PM_RSTC_WRCFG_FULL_RESET       0x00000020
  27  #define PM_RSTC_RESET                  0x00000102
  28 -
  29 -/*
  30 - * The Raspberry Pi firmware uses the RSTS register to know which partition
  31 - * to boot from. The partition value is spread into bits 0, 2, 4, 6, 8, 10.
  32 - * Partition 63 is a special partition used by the firmware to indicate halt.
  33 - */
  34 -#define PM_RSTS_RASPBERRYPI_HALT       0x555
  35 +#define PM_RSTS_PARTITION_CLR          0xfffffaaa
  36
  37  #define SECS_TO_WDOG_TICKS(x) ((x) << 16)
  38  #define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
  39 @@ -94,9 +88,24 @@ static unsigned int bcm2835_wdt_get_time
  40         return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
  41  }
  42
  43 -static void __bcm2835_restart(struct bcm2835_wdt *wdt)
  44 +/*
  45 + * The Raspberry Pi firmware uses the RSTS register to know which partiton
  46 + * to boot from. The partiton value is spread into bits 0, 2, 4, 6, 8, 10.
  47 + * Partiton 63 is a special partition used by the firmware to indicate halt.
  48 + */
  49 +
  50 +static void __bcm2835_restart(struct bcm2835_wdt *wdt, u8 partition)
  51  {
  52 -       u32 val;
  53 +       u32 val, rsts;
  54 +
  55 +       rsts = (partition & BIT(0)) | ((partition & BIT(1)) << 1) |
  56 +              ((partition & BIT(2)) << 2) | ((partition & BIT(3)) << 3) |
  57 +              ((partition & BIT(4)) << 4) | ((partition & BIT(5)) << 5);
  58 +
  59 +       val = readl_relaxed(wdt->base + PM_RSTS);
  60 +       val &= PM_RSTS_PARTITION_CLR;
  61 +       val |= PM_PASSWORD | rsts;
  62 +       writel_relaxed(val, wdt->base + PM_RSTS);
  63
  64         /* use a timeout of 10 ticks (~150us) */
  65         writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG);
  66 @@ -114,7 +123,13 @@ static int bcm2835_restart(struct watchd
  67  {
  68         struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
  69
  70 -       __bcm2835_restart(wdt);
  71 +       unsigned long long val;
  72 +       u8 partition = 0;
  73 +
  74 +       if (data && !kstrtoull(data, 0, &val) && val <= 63)
  75 +               partition = val;
  76 +
  77 +       __bcm2835_restart(wdt, partition);
  78
  79         return 0;
  80  }
  81 @@ -152,19 +167,9 @@ static void bcm2835_power_off(void)
  82                 of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt");
  83         struct platform_device *pdev = of_find_device_by_node(np);
  84         struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
  85 -       u32 val;
  86 -
  87 -       /*
  88 -        * We set the watchdog hard reset bit here to distinguish this reset
  89 -        * from the normal (full) reset. bootcode.bin will not reboot after a
  90 -        * hard reset.
  91 -        */
  92 -       val = readl_relaxed(wdt->base + PM_RSTS);
  93 -       val |= PM_PASSWORD | PM_RSTS_RASPBERRYPI_HALT;
  94 -       writel_relaxed(val, wdt->base + PM_RSTS);
  95
  96 -       /* Continue with normal reset mechanism */
  97 -       __bcm2835_restart(wdt);
  98 +       /* Partition 63 tells the firmware that this is a halt */
  99 +       __bcm2835_restart(wdt, 63);
 100  }
 101
 102  static int bcm2835_wdt_probe(struct platform_device *pdev)