drivers/watchdog/meson_gxbb_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
   2 /*
   3  * Copyright (c) 2016 BayLibre, SAS.
   4  * Author: Neil Armstrong <narmstrong@baylibre.com>
   5  *
   6  */
   7 #include <linux/clk.h>
   8 #include <linux/err.h>
   9 #include <linux/io.h>
  10 #include <linux/module.h>
  11 #include <linux/of.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/slab.h>
  14 #include <linux/types.h>
  15 #include <linux/watchdog.h>
  16
  17 #define DEFAULT_TIMEOUT 30      /* seconds */
  18
  19 #define GXBB_WDT_CTRL_REG                       0x0
  20 #define GXBB_WDT_TCNT_REG                       0x8
  21 #define GXBB_WDT_RSET_REG                       0xc
  22
  23 #define GXBB_WDT_CTRL_CLKDIV_EN                 BIT(25)
  24 #define GXBB_WDT_CTRL_CLK_EN                    BIT(24)
  25 #define GXBB_WDT_CTRL_EN                        BIT(18)
  26 #define GXBB_WDT_CTRL_DIV_MASK                  (BIT(18) - 1)
  27
  28 #define GXBB_WDT_TCNT_SETUP_MASK                (BIT(16) - 1)
  29 #define GXBB_WDT_TCNT_CNT_SHIFT                 16
  30
  31 static bool nowayout = WATCHDOG_NOWAYOUT;
  32 module_param(nowayout, bool, 0);
  33 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default="
  34                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  35
  36 static unsigned int timeout;
  37 module_param(timeout, uint, 0);
  38 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds="
  39                  __MODULE_STRING(DEFAULT_TIMEOUT) ")");
  40
  41 struct meson_gxbb_wdt {
  42         void __iomem *reg_base;
  43         struct watchdog_device wdt_dev;
  44         struct clk *clk;
  45 };
  46
  47 struct wdt_params {
  48         u32 rst;
  49 };
  50
  51 static int meson_gxbb_wdt_start(struct watchdog_device *wdt_dev)
  52 {
  53         struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
  54
  55         writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN,
  56                data->reg_base + GXBB_WDT_CTRL_REG);
  57
  58         return 0;
  59 }
  60
  61 static int meson_gxbb_wdt_stop(struct watchdog_device *wdt_dev)
  62 {
  63         struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
  64
  65         writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN,
  66                data->reg_base + GXBB_WDT_CTRL_REG);
  67
  68         return 0;
  69 }
  70
  71 static int meson_gxbb_wdt_ping(struct watchdog_device *wdt_dev)
  72 {
  73         struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
  74
  75         writel(0, data->reg_base + GXBB_WDT_RSET_REG);
  76
  77         return 0;
  78 }
  79
  80 static int meson_gxbb_wdt_set_timeout(struct watchdog_device *wdt_dev,
  81                                       unsigned int timeout)
  82 {
  83         struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
  84         unsigned long tcnt = timeout * 1000;
  85
  86         if (tcnt > GXBB_WDT_TCNT_SETUP_MASK)
  87                 tcnt = GXBB_WDT_TCNT_SETUP_MASK;
  88
  89         wdt_dev->timeout = timeout;
  90
  91         meson_gxbb_wdt_ping(wdt_dev);
  92
  93         writel(tcnt, data->reg_base + GXBB_WDT_TCNT_REG);
  94
  95         return 0;
  96 }
  97
  98 static unsigned int meson_gxbb_wdt_get_timeleft(struct watchdog_device *wdt_dev)
  99 {
 100         struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
 101         unsigned long reg;
 102
 103         reg = readl(data->reg_base + GXBB_WDT_TCNT_REG);
 104
 105         return ((reg & GXBB_WDT_TCNT_SETUP_MASK) -
 106                 (reg >> GXBB_WDT_TCNT_CNT_SHIFT)) / 1000;
 107 }
 108
 109 static const struct watchdog_ops meson_gxbb_wdt_ops = {
 110         .start = meson_gxbb_wdt_start,
 111         .stop = meson_gxbb_wdt_stop,
 112         .ping = meson_gxbb_wdt_ping,
 113         .set_timeout = meson_gxbb_wdt_set_timeout,
 114         .get_timeleft = meson_gxbb_wdt_get_timeleft,
 115 };
 116
 117 static const struct watchdog_info meson_gxbb_wdt_info = {
 118         .identity = "Meson GXBB Watchdog",
 119         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 120 };
 121
 122 static int __maybe_unused meson_gxbb_wdt_resume(struct device *dev)
 123 {
 124         struct meson_gxbb_wdt *data = dev_get_drvdata(dev);
 125
 126         if (watchdog_active(&data->wdt_dev))
 127                 meson_gxbb_wdt_start(&data->wdt_dev);
 128
 129         return 0;
 130 }
 131
 132 static int __maybe_unused meson_gxbb_wdt_suspend(struct device *dev)
 133 {
 134         struct meson_gxbb_wdt *data = dev_get_drvdata(dev);
 135
 136         if (watchdog_active(&data->wdt_dev))
 137                 meson_gxbb_wdt_stop(&data->wdt_dev);
 138
 139         return 0;
 140 }
 141
 142 static const struct dev_pm_ops meson_gxbb_wdt_pm_ops = {
 143         SET_SYSTEM_SLEEP_PM_OPS(meson_gxbb_wdt_suspend, meson_gxbb_wdt_resume)
 144 };
 145
 146 static const struct wdt_params gxbb_params = {
 147         .rst = BIT(21),
 148 };
 149
 150 static const struct wdt_params t7_params = {
 151         .rst = BIT(22),
 152 };
 153
 154 static const struct of_device_id meson_gxbb_wdt_dt_ids[] = {
 155          { .compatible = "amlogic,meson-gxbb-wdt", .data = &gxbb_params, },
 156          { .compatible = "amlogic,t7-wdt", .data = &t7_params, },
 157          { /* sentinel */ },
 158 };
 159 MODULE_DEVICE_TABLE(of, meson_gxbb_wdt_dt_ids);
 160
 161 static int meson_gxbb_wdt_probe(struct platform_device *pdev)
 162 {
 163         struct device *dev = &pdev->dev;
 164         struct meson_gxbb_wdt *data;
 165         struct wdt_params *params;
 166         u32 ctrl_reg;
 167
 168         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 169         if (!data)
 170                 return -ENOMEM;
 171
 172         data->reg_base = devm_platform_ioremap_resource(pdev, 0);
 173         if (IS_ERR(data->reg_base))
 174                 return PTR_ERR(data->reg_base);
 175
 176         data->clk = devm_clk_get_enabled(dev, NULL);
 177         if (IS_ERR(data->clk))
 178                 return PTR_ERR(data->clk);
 179
 180         params = (struct wdt_params *)of_device_get_match_data(dev);
 181
 182         platform_set_drvdata(pdev, data);
 183
 184         data->wdt_dev.parent = dev;
 185         data->wdt_dev.info = &meson_gxbb_wdt_info;
 186         data->wdt_dev.ops = &meson_gxbb_wdt_ops;
 187         data->wdt_dev.max_hw_heartbeat_ms = GXBB_WDT_TCNT_SETUP_MASK;
 188         data->wdt_dev.min_timeout = 1;
 189         data->wdt_dev.timeout = DEFAULT_TIMEOUT;
 190         watchdog_init_timeout(&data->wdt_dev, timeout, dev);
 191         watchdog_set_nowayout(&data->wdt_dev, nowayout);
 192         watchdog_set_drvdata(&data->wdt_dev, data);
 193
 194         ctrl_reg = readl(data->reg_base + GXBB_WDT_CTRL_REG) &
 195                                 GXBB_WDT_CTRL_EN;
 196
 197         if (ctrl_reg) {
 198                 /* Watchdog is running - keep it running but extend timeout
 199                  * to the maximum while setting the timebase
 200                  */
 201                 set_bit(WDOG_HW_RUNNING, &data->wdt_dev.status);
 202                 meson_gxbb_wdt_set_timeout(&data->wdt_dev,
 203                                 GXBB_WDT_TCNT_SETUP_MASK / 1000);
 204         }
 205
 206         /* Setup with 1ms timebase */
 207         ctrl_reg |= ((clk_get_rate(data->clk) / 1000) &
 208                         GXBB_WDT_CTRL_DIV_MASK) |
 209                         params->rst |
 210                         GXBB_WDT_CTRL_CLK_EN |
 211                         GXBB_WDT_CTRL_CLKDIV_EN;
 212
 213         writel(ctrl_reg, data->reg_base + GXBB_WDT_CTRL_REG);
 214         meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
 215
 216         return devm_watchdog_register_device(dev, &data->wdt_dev);
 217 }
 218
 219 static struct platform_driver meson_gxbb_wdt_driver = {
 220         .probe  = meson_gxbb_wdt_probe,
 221         .driver = {
 222                 .name = "meson-gxbb-wdt",
 223                 .pm = &meson_gxbb_wdt_pm_ops,
 224                 .of_match_table = meson_gxbb_wdt_dt_ids,
 225         },
 226 };
 227
 228 module_platform_driver(meson_gxbb_wdt_driver);
 229
 230 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
 231 MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver");
 232 MODULE_LICENSE("Dual BSD/GPL");