Carlo Caione | 22e1b8f | 2014-09-20 19:06:50 +0200 | [diff] [blame^] | 1 | /* |
| 2 | * Meson Watchdog Driver |
| 3 | * |
| 4 | * Copyright (c) 2014 Carlo Caione |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/clk.h> |
| 13 | #include <linux/delay.h> |
| 14 | #include <linux/err.h> |
| 15 | #include <linux/init.h> |
| 16 | #include <linux/io.h> |
| 17 | #include <linux/kernel.h> |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/moduleparam.h> |
| 20 | #include <linux/notifier.h> |
| 21 | #include <linux/of.h> |
| 22 | #include <linux/platform_device.h> |
| 23 | #include <linux/reboot.h> |
| 24 | #include <linux/types.h> |
| 25 | #include <linux/watchdog.h> |
| 26 | |
| 27 | #define DRV_NAME "meson_wdt" |
| 28 | |
| 29 | #define MESON_WDT_TC 0x00 |
| 30 | #define MESON_WDT_TC_EN BIT(22) |
| 31 | #define MESON_WDT_TC_TM_MASK 0x3fffff |
| 32 | #define MESON_WDT_DC_RESET (3 << 24) |
| 33 | |
| 34 | #define MESON_WDT_RESET 0x04 |
| 35 | |
| 36 | #define MESON_WDT_TIMEOUT 30 |
| 37 | #define MESON_WDT_MIN_TIMEOUT 1 |
| 38 | #define MESON_WDT_MAX_TIMEOUT (MESON_WDT_TC_TM_MASK / 100000) |
| 39 | |
| 40 | #define MESON_SEC_TO_TC(s) ((s) * 100000) |
| 41 | |
| 42 | static bool nowayout = WATCHDOG_NOWAYOUT; |
| 43 | static unsigned int timeout = MESON_WDT_TIMEOUT; |
| 44 | |
| 45 | struct meson_wdt_dev { |
| 46 | struct watchdog_device wdt_dev; |
| 47 | void __iomem *wdt_base; |
| 48 | struct notifier_block restart_handler; |
| 49 | }; |
| 50 | |
| 51 | static int meson_restart_handle(struct notifier_block *this, unsigned long mode, |
| 52 | void *cmd) |
| 53 | { |
| 54 | u32 tc_reboot = MESON_WDT_DC_RESET | MESON_WDT_TC_EN | 100; |
| 55 | struct meson_wdt_dev *meson_wdt = container_of(this, |
| 56 | struct meson_wdt_dev, |
| 57 | restart_handler); |
| 58 | |
| 59 | while (1) { |
| 60 | writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC); |
| 61 | mdelay(5); |
| 62 | } |
| 63 | |
| 64 | return NOTIFY_DONE; |
| 65 | } |
| 66 | |
| 67 | static int meson_wdt_ping(struct watchdog_device *wdt_dev) |
| 68 | { |
| 69 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); |
| 70 | |
| 71 | writel(0, meson_wdt->wdt_base + MESON_WDT_RESET); |
| 72 | |
| 73 | return 0; |
| 74 | } |
| 75 | |
| 76 | static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev, |
| 77 | unsigned int timeout) |
| 78 | { |
| 79 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); |
| 80 | u32 reg; |
| 81 | |
| 82 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); |
| 83 | reg &= ~MESON_WDT_TC_TM_MASK; |
| 84 | reg |= MESON_SEC_TO_TC(timeout); |
| 85 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); |
| 86 | } |
| 87 | |
| 88 | static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev, |
| 89 | unsigned int timeout) |
| 90 | { |
| 91 | wdt_dev->timeout = timeout; |
| 92 | |
| 93 | meson_wdt_change_timeout(wdt_dev, timeout); |
| 94 | meson_wdt_ping(wdt_dev); |
| 95 | |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | static int meson_wdt_stop(struct watchdog_device *wdt_dev) |
| 100 | { |
| 101 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); |
| 102 | u32 reg; |
| 103 | |
| 104 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); |
| 105 | reg &= ~MESON_WDT_TC_EN; |
| 106 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); |
| 107 | |
| 108 | return 0; |
| 109 | } |
| 110 | |
| 111 | static int meson_wdt_start(struct watchdog_device *wdt_dev) |
| 112 | { |
| 113 | struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); |
| 114 | u32 reg; |
| 115 | |
| 116 | meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout); |
| 117 | meson_wdt_ping(wdt_dev); |
| 118 | |
| 119 | reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); |
| 120 | reg |= MESON_WDT_TC_EN; |
| 121 | writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); |
| 122 | |
| 123 | return 0; |
| 124 | } |
| 125 | |
| 126 | static const struct watchdog_info meson_wdt_info = { |
| 127 | .identity = DRV_NAME, |
| 128 | .options = WDIOF_SETTIMEOUT | |
| 129 | WDIOF_KEEPALIVEPING | |
| 130 | WDIOF_MAGICCLOSE, |
| 131 | }; |
| 132 | |
| 133 | static const struct watchdog_ops meson_wdt_ops = { |
| 134 | .owner = THIS_MODULE, |
| 135 | .start = meson_wdt_start, |
| 136 | .stop = meson_wdt_stop, |
| 137 | .ping = meson_wdt_ping, |
| 138 | .set_timeout = meson_wdt_set_timeout, |
| 139 | }; |
| 140 | |
| 141 | static int meson_wdt_probe(struct platform_device *pdev) |
| 142 | { |
| 143 | struct resource *res; |
| 144 | struct meson_wdt_dev *meson_wdt; |
| 145 | int err; |
| 146 | |
| 147 | meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL); |
| 148 | if (!meson_wdt) |
| 149 | return -ENOMEM; |
| 150 | |
| 151 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 152 | meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); |
| 153 | if (IS_ERR(meson_wdt->wdt_base)) |
| 154 | return PTR_ERR(meson_wdt->wdt_base); |
| 155 | |
| 156 | meson_wdt->wdt_dev.parent = &pdev->dev; |
| 157 | meson_wdt->wdt_dev.info = &meson_wdt_info; |
| 158 | meson_wdt->wdt_dev.ops = &meson_wdt_ops; |
| 159 | meson_wdt->wdt_dev.timeout = MESON_WDT_TIMEOUT; |
| 160 | meson_wdt->wdt_dev.max_timeout = MESON_WDT_MAX_TIMEOUT; |
| 161 | meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT; |
| 162 | |
| 163 | watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt); |
| 164 | |
| 165 | watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev); |
| 166 | watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout); |
| 167 | |
| 168 | meson_wdt_stop(&meson_wdt->wdt_dev); |
| 169 | |
| 170 | err = watchdog_register_device(&meson_wdt->wdt_dev); |
| 171 | if (err) |
| 172 | return err; |
| 173 | |
| 174 | platform_set_drvdata(pdev, meson_wdt); |
| 175 | |
| 176 | meson_wdt->restart_handler.notifier_call = meson_restart_handle; |
| 177 | meson_wdt->restart_handler.priority = 128; |
| 178 | err = register_restart_handler(&meson_wdt->restart_handler); |
| 179 | if (err) |
| 180 | dev_err(&pdev->dev, |
| 181 | "cannot register restart handler (err=%d)\n", err); |
| 182 | |
| 183 | dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)", |
| 184 | meson_wdt->wdt_dev.timeout, nowayout); |
| 185 | |
| 186 | return 0; |
| 187 | } |
| 188 | |
| 189 | static int meson_wdt_remove(struct platform_device *pdev) |
| 190 | { |
| 191 | struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev); |
| 192 | |
| 193 | unregister_restart_handler(&meson_wdt->restart_handler); |
| 194 | |
| 195 | watchdog_unregister_device(&meson_wdt->wdt_dev); |
| 196 | |
| 197 | return 0; |
| 198 | } |
| 199 | |
| 200 | static void meson_wdt_shutdown(struct platform_device *pdev) |
| 201 | { |
| 202 | struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev); |
| 203 | |
| 204 | meson_wdt_stop(&meson_wdt->wdt_dev); |
| 205 | } |
| 206 | |
| 207 | static const struct of_device_id meson_wdt_dt_ids[] = { |
| 208 | { .compatible = "amlogic,meson6-wdt" }, |
| 209 | { /* sentinel */ } |
| 210 | }; |
| 211 | MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids); |
| 212 | |
| 213 | static struct platform_driver meson_wdt_driver = { |
| 214 | .probe = meson_wdt_probe, |
| 215 | .remove = meson_wdt_remove, |
| 216 | .shutdown = meson_wdt_shutdown, |
| 217 | .driver = { |
| 218 | .owner = THIS_MODULE, |
| 219 | .name = DRV_NAME, |
| 220 | .of_match_table = meson_wdt_dt_ids, |
| 221 | }, |
| 222 | }; |
| 223 | |
| 224 | module_platform_driver(meson_wdt_driver); |
| 225 | |
| 226 | module_param(timeout, uint, 0); |
| 227 | MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); |
| 228 | |
| 229 | module_param(nowayout, bool, 0); |
| 230 | MODULE_PARM_DESC(nowayout, |
| 231 | "Watchdog cannot be stopped once started (default=" |
| 232 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 233 | |
| 234 | MODULE_LICENSE("GPL"); |
| 235 | MODULE_AUTHOR("Carlo Caione <carlo@caione.org>"); |
| 236 | MODULE_DESCRIPTION("Meson Watchdog Timer Driver"); |