drivers/watchdog/bcm6345_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
   4  *
   5  * Derived from linux/drivers/watchdog/bcm63xx_wdt.c:
   6  *      Copyright (C) 2007 Miguel Gaio <miguel.gaio@efixo.com>
   7  *      Copyright (C) 2008 Florian Fainelli <florian@openwrt.org>
   8  */
   9
  10 #include <common.h>
  11 #include <dm.h>
  12 #include <wdt.h>
  13 #include <clk.h>
  14 #include <asm/io.h>
  15
  16 /* WDT Value register */
  17 #define WDT_VAL_REG             0x0
  18 #define WDT_VAL_MIN             0x00000002
  19 #define WDT_VAL_MAX             0xfffffffe
  20
  21 /* WDT Control register */
  22 #define WDT_CTL_REG             0x4
  23 #define WDT_CTL_START1_MASK     0x0000ff00
  24 #define WDT_CTL_START2_MASK     0x000000ff
  25 #define WDT_CTL_STOP1_MASK      0x0000ee00
  26 #define WDT_CTL_STOP2_MASK      0x000000ee
  27
  28 struct bcm6345_wdt_priv {
  29         void __iomem *regs;
  30         unsigned long clk_rate;
  31 };
  32
  33 static int bcm6345_wdt_reset(struct udevice *dev)
  34 {
  35         struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
  36
  37         writel(WDT_CTL_START1_MASK, priv->regs + WDT_CTL_REG);
  38         writel(WDT_CTL_START2_MASK, priv->regs + WDT_CTL_REG);
  39
  40         return 0;
  41 }
  42
  43 static int bcm6345_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
  44 {
  45         struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
  46         u32 val = priv->clk_rate / 1000 * timeout;
  47
  48         if (val < WDT_VAL_MIN) {
  49                 debug("watchdog won't fire with less than 2 ticks\n");
  50                 val = WDT_VAL_MIN;
  51         } else if (val > WDT_VAL_MAX) {
  52                 debug("maximum watchdog timeout exceeded\n");
  53                 val = WDT_VAL_MAX;
  54         }
  55
  56         writel(val, priv->regs + WDT_VAL_REG);
  57
  58         return bcm6345_wdt_reset(dev);
  59 }
  60
  61 static int bcm6345_wdt_expire_now(struct udevice *dev, ulong flags)
  62 {
  63         return bcm6345_wdt_start(dev, WDT_VAL_MIN, flags);
  64 }
  65
  66 static int bcm6345_wdt_stop(struct udevice *dev)
  67 {
  68         struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
  69
  70         writel(WDT_CTL_STOP1_MASK, priv->regs + WDT_CTL_REG);
  71         writel(WDT_CTL_STOP2_MASK, priv->regs + WDT_CTL_REG);
  72
  73         return 0;
  74 }
  75
  76 static const struct wdt_ops bcm6345_wdt_ops = {
  77         .expire_now = bcm6345_wdt_expire_now,
  78         .reset = bcm6345_wdt_reset,
  79         .start = bcm6345_wdt_start,
  80         .stop = bcm6345_wdt_stop,
  81 };
  82
  83 static const struct udevice_id bcm6345_wdt_ids[] = {
  84         { .compatible = "brcm,bcm6345-wdt" },
  85         { /* sentinel */ }
  86 };
  87
  88 static int bcm6345_wdt_probe(struct udevice *dev)
  89 {
  90         struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
  91         struct clk clk;
  92         int ret;
  93
  94         priv->regs = dev_remap_addr(dev);
  95         if (!priv->regs)
  96                 return -EINVAL;
  97
  98         ret = clk_get_by_index(dev, 0, &clk);
  99         if (!ret)
 100                 priv->clk_rate = clk_get_rate(&clk);
 101         else
 102                 return -EINVAL;
 103
 104         bcm6345_wdt_stop(dev);
 105
 106         return 0;
 107 }
 108
 109 U_BOOT_DRIVER(wdt_bcm6345) = {
 110         .name = "wdt_bcm6345",
 111         .id = UCLASS_WDT,
 112         .of_match = bcm6345_wdt_ids,
 113         .ops = &bcm6345_wdt_ops,
 114         .priv_auto_alloc_size = sizeof(struct bcm6345_wdt_priv),
 115         .probe = bcm6345_wdt_probe,
 116 };