target/linux/cns3xxx/patches-4.9/020-watchdog_support.patch

   1 Add a watchdog driver for ARM MPcore processors.
   2
   3 Signed-off-by: Felix Fietkau <nbd@nbd.name>
   4 ---
   5 --- a/drivers/watchdog/Kconfig
   6 +++ b/drivers/watchdog/Kconfig
   7 @@ -324,6 +324,13 @@ config KS8695_WATCHDOG
   8           Watchdog timer embedded into KS8695 processor. This will reboot your
   9           system when the timeout is reached.
  10
  11 +config MPCORE_WATCHDOG
  12 +       tristate "MPcore watchdog"
  13 +       depends on HAVE_ARM_TWD
  14 +       select WATCHDOG_CORE
  15 +       help
  16 +         Watchdog timer embedded into the MPcore system
  17 +
  18  config HAVE_S3C2410_WATCHDOG
  19         bool
  20         help
  21 --- a/drivers/watchdog/Makefile
  22 +++ b/drivers/watchdog/Makefile
  23 @@ -47,6 +47,7 @@ obj-$(CONFIG_21285_WATCHDOG) += wdt285.o
  24  obj-$(CONFIG_977_WATCHDOG) += wdt977.o
  25  obj-$(CONFIG_IXP4XX_WATCHDOG) += ixp4xx_wdt.o
  26  obj-$(CONFIG_KS8695_WATCHDOG) += ks8695_wdt.o
  27 +obj-$(CONFIG_MPCORE_WATCHDOG) += mpcore_wdt.o
  28  obj-$(CONFIG_S3C2410_WATCHDOG) += s3c2410_wdt.o
  29  obj-$(CONFIG_SA1100_WATCHDOG) += sa1100_wdt.o
  30  obj-$(CONFIG_SAMA5D4_WATCHDOG) += sama5d4_wdt.o
  31 --- /dev/null
  32 +++ b/drivers/watchdog/mpcore_wdt.c
  33 @@ -0,0 +1,117 @@
  34 +/*
  35 + * Watchdog driver for ARM MPcore
  36 + *
  37 + * Copyright (C) 2017 Felix Fietkau <nbd@nbd.name>
  38 + */
  39 +
  40 +#include <linux/module.h>
  41 +#include <linux/kernel.h>
  42 +#include <linux/watchdog.h>
  43 +#include <linux/platform_device.h>
  44 +#include <linux/io.h>
  45 +#include <asm/smp_twd.h>
  46 +
  47 +static void __iomem *wdt_base;
  48 +static int wdt_timeout = 60;
  49 +
  50 +static int mpcore_wdt_keepalive(struct watchdog_device *wdd)
  51 +{
  52 +       static int perturb;
  53 +       u32 count;
  54 +
  55 +       count = ioread32(wdt_base + TWD_WDOG_COUNTER);
  56 +       count = (~0U - count) * HZ / 5;
  57 +       count /= 256; /* prescale */
  58 +       count *= wdt_timeout;
  59 +
  60 +       /* Reload register needs a different value on each refresh */
  61 +       count += perturb;
  62 +       perturb = !perturb;
  63 +
  64 +       iowrite32(count, wdt_base + TWD_WDOG_LOAD);
  65 +
  66 +       return 0;
  67 +}
  68 +
  69 +static int mpcore_wdt_start(struct watchdog_device *wdd)
  70 +{
  71 +       mpcore_wdt_keepalive(wdd);
  72 +
  73 +       /* prescale = 256, mode = 1, enable = 1 */
  74 +       iowrite32(0x0000FF09, wdt_base + TWD_WDOG_CONTROL);
  75 +
  76 +       return 0;
  77 +}
  78 +
  79 +static int mpcore_wdt_stop(struct watchdog_device *wdd)
  80 +{
  81 +       iowrite32(0x12345678, wdt_base + TWD_WDOG_DISABLE);
  82 +       iowrite32(0x87654321, wdt_base + TWD_WDOG_DISABLE);
  83 +       iowrite32(0x0, wdt_base + TWD_WDOG_CONTROL);
  84 +
  85 +       return 0;
  86 +}
  87 +
  88 +static int mpcore_wdt_set_timeout(struct watchdog_device *wdd,
  89 +                                unsigned int timeout)
  90 +{
  91 +       mpcore_wdt_stop(wdd);
  92 +       wdt_timeout = timeout;
  93 +       mpcore_wdt_start(wdd);
  94 +
  95 +       return 0;
  96 +}
  97 +
  98 +static const struct watchdog_info mpcore_wdt_info = {
  99 +       .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 100 +       .identity = "MPcore Watchdog",
 101 +};
 102 +
 103 +static const struct watchdog_ops mpcore_wdt_ops = {
 104 +       .owner = THIS_MODULE,
 105 +       .start = mpcore_wdt_start,
 106 +       .stop  = mpcore_wdt_stop,
 107 +       .ping  = mpcore_wdt_keepalive,
 108 +       .set_timeout = mpcore_wdt_set_timeout,
 109 +};
 110 +
 111 +static struct watchdog_device mpcore_wdt = {
 112 +       .info = &mpcore_wdt_info,
 113 +       .ops = &mpcore_wdt_ops,
 114 +       .min_timeout = 1,
 115 +       .max_timeout = 65535,
 116 +};
 117 +
 118 +static int mpcore_wdt_probe(struct platform_device *pdev)
 119 +{
 120 +       struct resource *res;
 121 +
 122 +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 123 +       if (!res)
 124 +               return -ENODEV;
 125 +
 126 +       wdt_base = devm_ioremap_resource(&pdev->dev, res);
 127 +       if (IS_ERR(wdt_base))
 128 +               return PTR_ERR(wdt_base);
 129 +
 130 +       watchdog_register_device(&mpcore_wdt);
 131 +       return 0;
 132 +}
 133 +
 134 +static int mpcore_wdt_remove(struct platform_device *dev)
 135 +{
 136 +       watchdog_unregister_device(&mpcore_wdt);
 137 +       return 0;
 138 +}
 139 +
 140 +static struct platform_driver mpcore_wdt_driver = {
 141 +       .probe          = mpcore_wdt_probe,
 142 +       .remove         = mpcore_wdt_remove,
 143 +       .driver         = {
 144 +               .name   = "mpcore_wdt",
 145 +       },
 146 +};
 147 +
 148 +module_platform_driver(mpcore_wdt_driver);
 149 +MODULE_AUTHOR("Felix Fietkau <nbd@nbd.name>");
 150 +MODULE_LICENSE("GPL");