target/linux/brcm2708/patches-4.9/0023-watchdog-bcm2835-Support-setting-reboot-partition.patch

   1 From 259f169ef05f12bc7fed007befc11ed6c66dd9c8 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] 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 | 61 +++++++++++++++++++++++++-----------------
  20  1 file changed, 36 insertions(+), 25 deletions(-)
  21
  22 --- a/drivers/watchdog/bcm2835_wdt.c
  23 +++ b/drivers/watchdog/bcm2835_wdt.c
  24 @@ -35,13 +35,7 @@
  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 partiton
  31 - * to boot from. The partiton value is spread into bits 0, 2, 4, 6, 8, 10.
  32 - * Partiton 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 @@ -111,15 +105,28 @@ static struct watchdog_device bcm2835_wd
  40         .timeout =      WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
  41  };
  42
  43 -static int
  44 -bcm2835_restart(struct notifier_block *this, unsigned long mode, void *cmd)
  45 +/*
  46 + * The Raspberry Pi firmware uses the RSTS register to know which partiton
  47 + * to boot from. The partiton value is spread into bits 0, 2, 4, 6, 8, 10.
  48 + * Partiton 63 is a special partition used by the firmware to indicate halt.
  49 + */
  50 +
  51 +static void bcm2835_restart(struct bcm2835_wdt *wdt, u8 partition)
  52  {
  53 -       struct bcm2835_wdt *wdt = container_of(this, struct bcm2835_wdt,
  54 -                                              restart_handler);
  55 -       u32 val;
  56 +       u32 val, rsts;
  57 +
  58 +       rsts = (partition & BIT(0)) | ((partition & BIT(1)) << 1) |
  59 +              ((partition & BIT(2)) << 2) | ((partition & BIT(3)) << 3) |
  60 +              ((partition & BIT(4)) << 4) | ((partition & BIT(5)) << 5);
  61 +
  62 +       val = readl_relaxed(wdt->base + PM_RSTS);
  63 +       val &= PM_RSTS_PARTITION_CLR;
  64 +       val |= PM_PASSWORD | rsts;
  65 +       writel_relaxed(val, wdt->base + PM_RSTS);
  66
  67         /* use a timeout of 10 ticks (~150us) */
  68         writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG);
  69 +
  70         val = readl_relaxed(wdt->base + PM_RSTC);
  71         val &= PM_RSTC_WRCFG_CLR;
  72         val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
  73 @@ -127,6 +134,20 @@ bcm2835_restart(struct notifier_block *t
  74
  75         /* No sleeping, possibly atomic. */
  76         mdelay(1);
  77 +}
  78 +
  79 +static int bcm2835_restart_notifier_call(struct notifier_block *this,
  80 +                                        unsigned long mode, void *cmd)
  81 +{
  82 +       struct bcm2835_wdt *wdt = container_of(this, struct bcm2835_wdt,
  83 +                                              restart_handler);
  84 +       unsigned long long val;
  85 +       u8 partition = 0;
  86 +
  87 +       if (cmd && !kstrtoull(cmd, 0, &val) && val <= 63)
  88 +               partition = val;
  89 +
  90 +       bcm2835_restart(wdt, partition);
  91
  92         return 0;
  93  }
  94 @@ -142,19 +163,9 @@ static void bcm2835_power_off(void)
  95                 of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt");
  96         struct platform_device *pdev = of_find_device_by_node(np);
  97         struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
  98 -       u32 val;
  99 -
 100 -       /*
 101 -        * We set the watchdog hard reset bit here to distinguish this reset
 102 -        * from the normal (full) reset. bootcode.bin will not reboot after a
 103 -        * hard reset.
 104 -        */
 105 -       val = readl_relaxed(wdt->base + PM_RSTS);
 106 -       val |= PM_PASSWORD | PM_RSTS_RASPBERRYPI_HALT;
 107 -       writel_relaxed(val, wdt->base + PM_RSTS);
 108
 109 -       /* Continue with normal reset mechanism */
 110 -       bcm2835_restart(&wdt->restart_handler, REBOOT_HARD, NULL);
 111 +       /* Partition 63 tells the firmware that this is a halt */
 112 +       bcm2835_restart(wdt, 63);
 113  }
 114
 115  static int bcm2835_wdt_probe(struct platform_device *pdev)
 116 @@ -188,7 +199,7 @@ static int bcm2835_wdt_probe(struct plat
 117                 return err;
 118         }
 119
 120 -       wdt->restart_handler.notifier_call = bcm2835_restart;
 121 +       wdt->restart_handler.notifier_call = bcm2835_restart_notifier_call;
 122         wdt->restart_handler.priority = 128;
 123         register_restart_handler(&wdt->restart_handler);
 124         if (pm_power_off == NULL)