| 1 | /* |
| 2 | * drivers/watchdog/orion_wdt.c |
| 3 | * |
| 4 | * Watchdog driver for Orion/Kirkwood processors |
| 5 | * |
| 6 | * Author: Sylver Bruneau <sylver.bruneau@googlemail.com> |
| 7 | * |
| 8 | * This file is licensed under the terms of the GNU General Public |
| 9 | * License version 2. This program is licensed "as is" without any |
| 10 | * warranty of any kind, whether express or implied. |
| 11 | */ |
| 12 | |
| 13 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 14 | |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/moduleparam.h> |
| 17 | #include <linux/types.h> |
| 18 | #include <linux/kernel.h> |
| 19 | #include <linux/miscdevice.h> |
| 20 | #include <linux/platform_device.h> |
| 21 | #include <linux/watchdog.h> |
| 22 | #include <linux/init.h> |
| 23 | #include <linux/io.h> |
| 24 | #include <linux/spinlock.h> |
| 25 | #include <linux/clk.h> |
| 26 | #include <linux/err.h> |
| 27 | #include <linux/of.h> |
| 28 | #include <mach/bridge-regs.h> |
| 29 | |
| 30 | /* |
| 31 | * Watchdog timer block registers. |
| 32 | */ |
| 33 | #define TIMER_CTRL 0x0000 |
| 34 | #define WDT_EN 0x0010 |
| 35 | #define WDT_VAL 0x0024 |
| 36 | |
| 37 | #define WDT_MAX_CYCLE_COUNT 0xffffffff |
| 38 | #define WDT_IN_USE 0 |
| 39 | #define WDT_OK_TO_CLOSE 1 |
| 40 | |
| 41 | #define WDT_RESET_OUT_EN BIT(1) |
| 42 | #define WDT_INT_REQ BIT(3) |
| 43 | |
| 44 | static bool nowayout = WATCHDOG_NOWAYOUT; |
| 45 | static int heartbeat = -1; /* module parameter (seconds) */ |
| 46 | static unsigned int wdt_max_duration; /* (seconds) */ |
| 47 | static struct clk *clk; |
| 48 | static unsigned int wdt_tclk; |
| 49 | static void __iomem *wdt_reg; |
| 50 | static DEFINE_SPINLOCK(wdt_lock); |
| 51 | |
| 52 | static int orion_wdt_ping(struct watchdog_device *wdt_dev) |
| 53 | { |
| 54 | spin_lock(&wdt_lock); |
| 55 | |
| 56 | /* Reload watchdog duration */ |
| 57 | writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL); |
| 58 | |
| 59 | spin_unlock(&wdt_lock); |
| 60 | return 0; |
| 61 | } |
| 62 | |
| 63 | static int orion_wdt_start(struct watchdog_device *wdt_dev) |
| 64 | { |
| 65 | u32 reg; |
| 66 | |
| 67 | spin_lock(&wdt_lock); |
| 68 | |
| 69 | /* Set watchdog duration */ |
| 70 | writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL); |
| 71 | |
| 72 | /* Clear watchdog timer interrupt */ |
| 73 | writel(~WDT_INT_REQ, BRIDGE_CAUSE); |
| 74 | |
| 75 | /* Enable watchdog timer */ |
| 76 | reg = readl(wdt_reg + TIMER_CTRL); |
| 77 | reg |= WDT_EN; |
| 78 | writel(reg, wdt_reg + TIMER_CTRL); |
| 79 | |
| 80 | /* Enable reset on watchdog */ |
| 81 | reg = readl(RSTOUTn_MASK); |
| 82 | reg |= WDT_RESET_OUT_EN; |
| 83 | writel(reg, RSTOUTn_MASK); |
| 84 | |
| 85 | spin_unlock(&wdt_lock); |
| 86 | return 0; |
| 87 | } |
| 88 | |
| 89 | static int orion_wdt_stop(struct watchdog_device *wdt_dev) |
| 90 | { |
| 91 | u32 reg; |
| 92 | |
| 93 | spin_lock(&wdt_lock); |
| 94 | |
| 95 | /* Disable reset on watchdog */ |
| 96 | reg = readl(RSTOUTn_MASK); |
| 97 | reg &= ~WDT_RESET_OUT_EN; |
| 98 | writel(reg, RSTOUTn_MASK); |
| 99 | |
| 100 | /* Disable watchdog timer */ |
| 101 | reg = readl(wdt_reg + TIMER_CTRL); |
| 102 | reg &= ~WDT_EN; |
| 103 | writel(reg, wdt_reg + TIMER_CTRL); |
| 104 | |
| 105 | spin_unlock(&wdt_lock); |
| 106 | return 0; |
| 107 | } |
| 108 | |
| 109 | static unsigned int orion_wdt_get_timeleft(struct watchdog_device *wdt_dev) |
| 110 | { |
| 111 | unsigned int time_left; |
| 112 | |
| 113 | spin_lock(&wdt_lock); |
| 114 | time_left = readl(wdt_reg + WDT_VAL) / wdt_tclk; |
| 115 | spin_unlock(&wdt_lock); |
| 116 | |
| 117 | return time_left; |
| 118 | } |
| 119 | |
| 120 | static int orion_wdt_set_timeout(struct watchdog_device *wdt_dev, |
| 121 | unsigned int timeout) |
| 122 | { |
| 123 | wdt_dev->timeout = timeout; |
| 124 | return 0; |
| 125 | } |
| 126 | |
| 127 | static const struct watchdog_info orion_wdt_info = { |
| 128 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
| 129 | .identity = "Orion Watchdog", |
| 130 | }; |
| 131 | |
| 132 | static const struct watchdog_ops orion_wdt_ops = { |
| 133 | .owner = THIS_MODULE, |
| 134 | .start = orion_wdt_start, |
| 135 | .stop = orion_wdt_stop, |
| 136 | .ping = orion_wdt_ping, |
| 137 | .set_timeout = orion_wdt_set_timeout, |
| 138 | .get_timeleft = orion_wdt_get_timeleft, |
| 139 | }; |
| 140 | |
| 141 | static struct watchdog_device orion_wdt = { |
| 142 | .info = &orion_wdt_info, |
| 143 | .ops = &orion_wdt_ops, |
| 144 | .min_timeout = 1, |
| 145 | }; |
| 146 | |
| 147 | static int orion_wdt_probe(struct platform_device *pdev) |
| 148 | { |
| 149 | struct resource *res; |
| 150 | int ret; |
| 151 | |
| 152 | clk = devm_clk_get(&pdev->dev, NULL); |
| 153 | if (IS_ERR(clk)) { |
| 154 | dev_err(&pdev->dev, "Orion Watchdog missing clock\n"); |
| 155 | return -ENODEV; |
| 156 | } |
| 157 | clk_prepare_enable(clk); |
| 158 | wdt_tclk = clk_get_rate(clk); |
| 159 | |
| 160 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 161 | if (!res) |
| 162 | return -ENODEV; |
| 163 | wdt_reg = devm_ioremap(&pdev->dev, res->start, resource_size(res)); |
| 164 | if (!wdt_reg) |
| 165 | return -ENOMEM; |
| 166 | |
| 167 | wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk; |
| 168 | |
| 169 | orion_wdt.timeout = wdt_max_duration; |
| 170 | orion_wdt.max_timeout = wdt_max_duration; |
| 171 | watchdog_init_timeout(&orion_wdt, heartbeat, &pdev->dev); |
| 172 | |
| 173 | watchdog_set_nowayout(&orion_wdt, nowayout); |
| 174 | ret = watchdog_register_device(&orion_wdt); |
| 175 | if (ret) { |
| 176 | clk_disable_unprepare(clk); |
| 177 | return ret; |
| 178 | } |
| 179 | |
| 180 | pr_info("Initial timeout %d sec%s\n", |
| 181 | orion_wdt.timeout, nowayout ? ", nowayout" : ""); |
| 182 | return 0; |
| 183 | } |
| 184 | |
| 185 | static int orion_wdt_remove(struct platform_device *pdev) |
| 186 | { |
| 187 | watchdog_unregister_device(&orion_wdt); |
| 188 | clk_disable_unprepare(clk); |
| 189 | return 0; |
| 190 | } |
| 191 | |
| 192 | static void orion_wdt_shutdown(struct platform_device *pdev) |
| 193 | { |
| 194 | orion_wdt_stop(&orion_wdt); |
| 195 | } |
| 196 | |
| 197 | static const struct of_device_id orion_wdt_of_match_table[] = { |
| 198 | { .compatible = "marvell,orion-wdt", }, |
| 199 | {}, |
| 200 | }; |
| 201 | MODULE_DEVICE_TABLE(of, orion_wdt_of_match_table); |
| 202 | |
| 203 | static struct platform_driver orion_wdt_driver = { |
| 204 | .probe = orion_wdt_probe, |
| 205 | .remove = orion_wdt_remove, |
| 206 | .shutdown = orion_wdt_shutdown, |
| 207 | .driver = { |
| 208 | .owner = THIS_MODULE, |
| 209 | .name = "orion_wdt", |
| 210 | .of_match_table = of_match_ptr(orion_wdt_of_match_table), |
| 211 | }, |
| 212 | }; |
| 213 | |
| 214 | module_platform_driver(orion_wdt_driver); |
| 215 | |
| 216 | MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>"); |
| 217 | MODULE_DESCRIPTION("Orion Processor Watchdog"); |
| 218 | |
| 219 | module_param(heartbeat, int, 0); |
| 220 | MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds"); |
| 221 | |
| 222 | module_param(nowayout, bool, 0); |
| 223 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
| 224 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 225 | |
| 226 | MODULE_LICENSE("GPL"); |
| 227 | MODULE_ALIAS("platform:orion_wdt"); |
| 228 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |