Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 1 | /* |
| 2 | * drivers/char/watchdog/max63xx_wdt.c |
| 3 | * |
| 4 | * Driver for max63{69,70,71,72,73,74} watchdog timers |
| 5 | * |
| 6 | * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org> |
| 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 | * This driver assumes the watchdog pins are memory mapped (as it is |
| 13 | * the case for the Arcom Zeus). Should it be connected over GPIOs or |
| 14 | * another interface, some abstraction will have to be introduced. |
| 15 | */ |
| 16 | |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/moduleparam.h> |
| 19 | #include <linux/types.h> |
| 20 | #include <linux/kernel.h> |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 21 | #include <linux/miscdevice.h> |
| 22 | #include <linux/watchdog.h> |
| 23 | #include <linux/init.h> |
| 24 | #include <linux/bitops.h> |
| 25 | #include <linux/platform_device.h> |
| 26 | #include <linux/spinlock.h> |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 27 | #include <linux/io.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 28 | #include <linux/slab.h> |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 29 | |
| 30 | #define DEFAULT_HEARTBEAT 60 |
| 31 | #define MAX_HEARTBEAT 60 |
| 32 | |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 33 | static unsigned int heartbeat = DEFAULT_HEARTBEAT; |
Wim Van Sebroeck | 86a1e18 | 2012-03-05 16:51:11 +0100 | [diff] [blame] | 34 | static bool nowayout = WATCHDOG_NOWAYOUT; |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 35 | |
| 36 | /* |
| 37 | * Memory mapping: a single byte, 3 first lower bits to select bit 3 |
| 38 | * to ping the watchdog. |
| 39 | */ |
| 40 | #define MAX6369_WDSET (7 << 0) |
Wim Van Sebroeck | 5f3b275 | 2011-02-23 20:04:38 +0000 | [diff] [blame] | 41 | #define MAX6369_WDI (1 << 3) |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 42 | |
| 43 | static DEFINE_SPINLOCK(io_lock); |
| 44 | |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 45 | static int nodelay; |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 46 | static void __iomem *wdt_base; |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 47 | |
| 48 | /* |
| 49 | * The timeout values used are actually the absolute minimum the chip |
| 50 | * offers. Typical values on my board are slightly over twice as long |
| 51 | * (10s setting ends up with a 25s timeout), and can be up to 3 times |
| 52 | * the nominal setting (according to the datasheet). So please take |
| 53 | * these values with a grain of salt. Same goes for the initial delay |
| 54 | * "feature". Only max6373/74 have a few settings without this initial |
| 55 | * delay (selected with the "nodelay" parameter). |
| 56 | * |
| 57 | * I also decided to remove from the tables any timeout smaller than a |
| 58 | * second, as it looked completly overkill... |
| 59 | */ |
| 60 | |
| 61 | /* Timeouts in second */ |
| 62 | struct max63xx_timeout { |
| 63 | u8 wdset; |
| 64 | u8 tdelay; |
| 65 | u8 twd; |
| 66 | }; |
| 67 | |
| 68 | static struct max63xx_timeout max6369_table[] = { |
| 69 | { 5, 1, 1 }, |
| 70 | { 6, 10, 10 }, |
| 71 | { 7, 60, 60 }, |
| 72 | { }, |
| 73 | }; |
| 74 | |
| 75 | static struct max63xx_timeout max6371_table[] = { |
| 76 | { 6, 60, 3 }, |
| 77 | { 7, 60, 60 }, |
| 78 | { }, |
| 79 | }; |
| 80 | |
| 81 | static struct max63xx_timeout max6373_table[] = { |
| 82 | { 2, 60, 1 }, |
| 83 | { 5, 0, 1 }, |
| 84 | { 1, 3, 3 }, |
| 85 | { 7, 60, 10 }, |
| 86 | { 6, 0, 10 }, |
| 87 | { }, |
| 88 | }; |
| 89 | |
| 90 | static struct max63xx_timeout *current_timeout; |
| 91 | |
| 92 | static struct max63xx_timeout * |
| 93 | max63xx_select_timeout(struct max63xx_timeout *table, int value) |
| 94 | { |
| 95 | while (table->twd) { |
| 96 | if (value <= table->twd) { |
| 97 | if (nodelay && table->tdelay == 0) |
| 98 | return table; |
| 99 | |
| 100 | if (!nodelay) |
| 101 | return table; |
| 102 | } |
| 103 | |
| 104 | table++; |
| 105 | } |
| 106 | |
| 107 | return NULL; |
| 108 | } |
| 109 | |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 110 | static int max63xx_wdt_ping(struct watchdog_device *wdd) |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 111 | { |
| 112 | u8 val; |
| 113 | |
| 114 | spin_lock(&io_lock); |
| 115 | |
| 116 | val = __raw_readb(wdt_base); |
| 117 | |
| 118 | __raw_writeb(val | MAX6369_WDI, wdt_base); |
| 119 | __raw_writeb(val & ~MAX6369_WDI, wdt_base); |
| 120 | |
| 121 | spin_unlock(&io_lock); |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 122 | return 0; |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 123 | } |
| 124 | |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 125 | static int max63xx_wdt_start(struct watchdog_device *wdd) |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 126 | { |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 127 | struct max63xx_timeout *entry = watchdog_get_drvdata(wdd); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 128 | u8 val; |
| 129 | |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 130 | spin_lock(&io_lock); |
| 131 | |
| 132 | val = __raw_readb(wdt_base); |
| 133 | val &= ~MAX6369_WDSET; |
| 134 | val |= entry->wdset; |
| 135 | __raw_writeb(val, wdt_base); |
| 136 | |
| 137 | spin_unlock(&io_lock); |
| 138 | |
| 139 | /* check for a edge triggered startup */ |
| 140 | if (entry->tdelay == 0) |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 141 | max63xx_wdt_ping(wdd); |
| 142 | return 0; |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 143 | } |
| 144 | |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 145 | static int max63xx_wdt_stop(struct watchdog_device *wdd) |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 146 | { |
Marc Zyngier | b1183e0 | 2010-04-09 17:43:33 +0100 | [diff] [blame] | 147 | u8 val; |
| 148 | |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 149 | spin_lock(&io_lock); |
| 150 | |
Marc Zyngier | b1183e0 | 2010-04-09 17:43:33 +0100 | [diff] [blame] | 151 | val = __raw_readb(wdt_base); |
| 152 | val &= ~MAX6369_WDSET; |
| 153 | val |= 3; |
| 154 | __raw_writeb(val, wdt_base); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 155 | |
| 156 | spin_unlock(&io_lock); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 157 | return 0; |
| 158 | } |
| 159 | |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 160 | static const struct watchdog_info max63xx_wdt_info = { |
| 161 | .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
| 162 | .identity = "max63xx Watchdog", |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 163 | }; |
| 164 | |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 165 | static const struct watchdog_ops max63xx_wdt_ops = { |
| 166 | .owner = THIS_MODULE, |
| 167 | .start = max63xx_wdt_start, |
| 168 | .stop = max63xx_wdt_stop, |
| 169 | .ping = max63xx_wdt_ping, |
| 170 | }; |
| 171 | |
| 172 | static struct watchdog_device max63xx_wdt_dev = { |
| 173 | .info = &max63xx_wdt_info, |
| 174 | .ops = &max63xx_wdt_ops, |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 175 | }; |
| 176 | |
| 177 | static int __devinit max63xx_wdt_probe(struct platform_device *pdev) |
| 178 | { |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 179 | struct resource *wdt_mem; |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 180 | struct max63xx_timeout *table; |
| 181 | |
| 182 | table = (struct max63xx_timeout *)pdev->id_entry->driver_data; |
| 183 | |
| 184 | if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) |
| 185 | heartbeat = DEFAULT_HEARTBEAT; |
| 186 | |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 187 | dev_info(&pdev->dev, "requesting %ds heartbeat\n", heartbeat); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 188 | current_timeout = max63xx_select_timeout(table, heartbeat); |
| 189 | |
| 190 | if (!current_timeout) { |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 191 | dev_err(&pdev->dev, "unable to satisfy heartbeat request\n"); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 192 | return -EINVAL; |
| 193 | } |
| 194 | |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 195 | dev_info(&pdev->dev, "using %ds heartbeat with %ds initial delay\n", |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 196 | current_timeout->twd, current_timeout->tdelay); |
| 197 | |
| 198 | heartbeat = current_timeout->twd; |
| 199 | |
Julia Lawall | f712eac | 2011-02-26 17:34:39 +0100 | [diff] [blame] | 200 | wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 201 | wdt_base = devm_request_and_ioremap(&pdev->dev, wdt_mem); |
| 202 | if (!wdt_base) |
| 203 | return -ENOMEM; |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 204 | |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 205 | max63xx_wdt_dev.timeout = heartbeat; |
| 206 | watchdog_set_nowayout(&max63xx_wdt_dev, nowayout); |
| 207 | watchdog_set_drvdata(&max63xx_wdt_dev, current_timeout); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 208 | |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 209 | return watchdog_register_device(&max63xx_wdt_dev); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 210 | } |
| 211 | |
| 212 | static int __devexit max63xx_wdt_remove(struct platform_device *pdev) |
| 213 | { |
Axel Lin | a0f3683 | 2012-02-08 14:24:10 +0800 | [diff] [blame^] | 214 | watchdog_unregister_device(&max63xx_wdt_dev); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 215 | return 0; |
| 216 | } |
| 217 | |
| 218 | static struct platform_device_id max63xx_id_table[] = { |
| 219 | { "max6369_wdt", (kernel_ulong_t)max6369_table, }, |
| 220 | { "max6370_wdt", (kernel_ulong_t)max6369_table, }, |
| 221 | { "max6371_wdt", (kernel_ulong_t)max6371_table, }, |
| 222 | { "max6372_wdt", (kernel_ulong_t)max6371_table, }, |
| 223 | { "max6373_wdt", (kernel_ulong_t)max6373_table, }, |
| 224 | { "max6374_wdt", (kernel_ulong_t)max6373_table, }, |
| 225 | { }, |
| 226 | }; |
| 227 | MODULE_DEVICE_TABLE(platform, max63xx_id_table); |
| 228 | |
| 229 | static struct platform_driver max63xx_wdt_driver = { |
| 230 | .probe = max63xx_wdt_probe, |
| 231 | .remove = __devexit_p(max63xx_wdt_remove), |
| 232 | .id_table = max63xx_id_table, |
| 233 | .driver = { |
| 234 | .name = "max63xx_wdt", |
| 235 | .owner = THIS_MODULE, |
| 236 | }, |
| 237 | }; |
| 238 | |
Axel Lin | b8ec611 | 2011-11-29 13:56:27 +0800 | [diff] [blame] | 239 | module_platform_driver(max63xx_wdt_driver); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 240 | |
| 241 | MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>"); |
| 242 | MODULE_DESCRIPTION("max63xx Watchdog Driver"); |
| 243 | |
| 244 | module_param(heartbeat, int, 0); |
| 245 | MODULE_PARM_DESC(heartbeat, |
| 246 | "Watchdog heartbeat period in seconds from 1 to " |
| 247 | __MODULE_STRING(MAX_HEARTBEAT) ", default " |
| 248 | __MODULE_STRING(DEFAULT_HEARTBEAT)); |
| 249 | |
Wim Van Sebroeck | 86a1e18 | 2012-03-05 16:51:11 +0100 | [diff] [blame] | 250 | module_param(nowayout, bool, 0); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 251 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
| 252 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 253 | |
| 254 | module_param(nodelay, int, 0); |
| 255 | MODULE_PARM_DESC(nodelay, |
| 256 | "Force selection of a timeout setting without initial delay " |
| 257 | "(max6373/74 only, default=0)"); |
| 258 | |
| 259 | MODULE_LICENSE("GPL"); |
| 260 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |