drivers/watchdog/meson_gxbb_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (c) 2022 BayLibre, SAS.
   4  */
   5
   6 #include <clk.h>
   7 #include <dm.h>
   8 #include <dm/device_compat.h>
   9 #include <reset.h>
  10 #include <wdt.h>
  11 #include <asm/io.h>
  12 #include <linux/bitops.h>
  13
  14 #define GXBB_WDT_CTRL_REG                       0x0
  15 #define GXBB_WDT_TCNT_REG                       0x8
  16 #define GXBB_WDT_RSET_REG                       0xc
  17
  18 #define GXBB_WDT_CTRL_SYS_RESET_NOW             BIT(26)
  19 #define GXBB_WDT_CTRL_CLKDIV_EN                 BIT(25)
  20 #define GXBB_WDT_CTRL_CLK_EN                    BIT(24)
  21 #define GXBB_WDT_CTRL_EE_RESET                  BIT(21)
  22 #define GXBB_WDT_CTRL_EN                        BIT(18)
  23
  24 #define GXBB_WDT_CTRL_DIV_MASK                  GENMASK(17, 0)
  25 #define GXBB_WDT_TCNT_SETUP_MASK                GENMASK(15, 0)
  26
  27
  28 struct amlogic_wdt_priv {
  29         void __iomem *reg_base;
  30 };
  31
  32 static int amlogic_wdt_set_timeout(struct udevice *dev, u64 timeout_ms)
  33 {
  34         struct amlogic_wdt_priv *data = dev_get_priv(dev);
  35
  36         if (timeout_ms > GXBB_WDT_TCNT_SETUP_MASK) {
  37                 dev_warn(dev, "%s: timeout_ms=%llu: maximum watchdog timeout exceeded\n",
  38                          __func__, timeout_ms);
  39                 timeout_ms = GXBB_WDT_TCNT_SETUP_MASK;
  40         }
  41
  42         writel(timeout_ms, data->reg_base + GXBB_WDT_TCNT_REG);
  43
  44         return 0;
  45 }
  46
  47 static int amlogic_wdt_stop(struct udevice *dev)
  48 {
  49         struct amlogic_wdt_priv *data = dev_get_priv(dev);
  50
  51         writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN,
  52                data->reg_base + GXBB_WDT_CTRL_REG);
  53
  54         return 0;
  55 }
  56
  57 static int amlogic_wdt_start(struct udevice *dev, u64 time_ms, ulong flags)
  58 {
  59         struct amlogic_wdt_priv *data = dev_get_priv(dev);
  60
  61         writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN,
  62                data->reg_base + GXBB_WDT_CTRL_REG);
  63
  64         return amlogic_wdt_set_timeout(dev, time_ms);
  65 }
  66
  67 static int amlogic_wdt_reset(struct udevice *dev)
  68 {
  69         struct amlogic_wdt_priv *data = dev_get_priv(dev);
  70
  71         writel(0, data->reg_base + GXBB_WDT_RSET_REG);
  72
  73         return 0;
  74 }
  75
  76 static int amlogic_wdt_expire_now(struct udevice *dev, ulong flags)
  77 {
  78         struct amlogic_wdt_priv *data = dev_get_priv(dev);
  79
  80         writel(0, data->reg_base + GXBB_WDT_CTRL_SYS_RESET_NOW);
  81
  82         return 0;
  83 }
  84
  85 static int amlogic_wdt_probe(struct udevice *dev)
  86 {
  87         struct amlogic_wdt_priv *data = dev_get_priv(dev);
  88         int ret;
  89
  90         data->reg_base = dev_remap_addr(dev);
  91         if (!data->reg_base)
  92                 return -EINVAL;
  93
  94         struct clk clk;
  95
  96         ret = clk_get_by_index(dev, 0, &clk);
  97         if (ret)
  98                 return ret;
  99
 100         ret = clk_enable(&clk);
 101         if (ret)
 102                 return ret;
 103
 104         /* Setup with 1ms timebase */
 105         writel(((clk_get_rate(&clk) / 1000) & GXBB_WDT_CTRL_DIV_MASK) |
 106                GXBB_WDT_CTRL_EE_RESET |
 107                GXBB_WDT_CTRL_CLK_EN |
 108                GXBB_WDT_CTRL_CLKDIV_EN,
 109                data->reg_base + GXBB_WDT_CTRL_REG);
 110
 111         return 0;
 112 }
 113
 114 static const struct wdt_ops amlogic_wdt_ops = {
 115         .start = amlogic_wdt_start,
 116         .reset = amlogic_wdt_reset,
 117         .stop = amlogic_wdt_stop,
 118         .expire_now = amlogic_wdt_expire_now,
 119 };
 120
 121 static const struct udevice_id amlogic_wdt_ids[] = {
 122         { .compatible = "amlogic,meson-gxbb-wdt" },
 123         {}
 124 };
 125
 126 U_BOOT_DRIVER(amlogic_wdt) = {
 127         .name = "amlogic_wdt",
 128         .id = UCLASS_WDT,
 129         .of_match = amlogic_wdt_ids,
 130         .priv_auto = sizeof(struct amlogic_wdt_priv),
 131         .probe = amlogic_wdt_probe,
 132         .ops = &amlogic_wdt_ops,
 133         .flags = DM_FLAG_PRE_RELOC,
 134 };