Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 1 | /* |
| 2 | * drivers/char/watchdog/davinci_wdt.c |
| 3 | * |
| 4 | * Watchdog driver for DaVinci DM644x/DM646x processors |
| 5 | * |
| 6 | * Copyright (C) 2006 Texas Instruments. |
| 7 | * |
| 8 | * 2007 (c) MontaVista Software, Inc. This file is licensed under |
| 9 | * the terms of the GNU General Public License version 2. This program |
| 10 | * is licensed "as is" without any warranty of any kind, whether express |
| 11 | * or implied. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/moduleparam.h> |
| 16 | #include <linux/types.h> |
| 17 | #include <linux/kernel.h> |
| 18 | #include <linux/fs.h> |
| 19 | #include <linux/miscdevice.h> |
| 20 | #include <linux/watchdog.h> |
| 21 | #include <linux/init.h> |
| 22 | #include <linux/bitops.h> |
| 23 | #include <linux/platform_device.h> |
| 24 | #include <linux/spinlock.h> |
Alan Cox | f78b0a8 | 2008-05-19 14:05:30 +0100 | [diff] [blame] | 25 | #include <linux/uaccess.h> |
| 26 | #include <linux/io.h> |
Russell King | a09e64f | 2008-08-05 16:14:15 +0100 | [diff] [blame] | 27 | #include <mach/hardware.h> |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 28 | |
| 29 | #define MODULE_NAME "DAVINCI-WDT: " |
| 30 | |
| 31 | #define DEFAULT_HEARTBEAT 60 |
| 32 | #define MAX_HEARTBEAT 600 /* really the max margin is 264/27MHz*/ |
| 33 | |
| 34 | /* Timer register set definition */ |
| 35 | #define PID12 (0x0) |
| 36 | #define EMUMGT (0x4) |
| 37 | #define TIM12 (0x10) |
| 38 | #define TIM34 (0x14) |
| 39 | #define PRD12 (0x18) |
| 40 | #define PRD34 (0x1C) |
| 41 | #define TCR (0x20) |
| 42 | #define TGCR (0x24) |
| 43 | #define WDTCR (0x28) |
| 44 | |
| 45 | /* TCR bit definitions */ |
| 46 | #define ENAMODE12_DISABLED (0 << 6) |
| 47 | #define ENAMODE12_ONESHOT (1 << 6) |
| 48 | #define ENAMODE12_PERIODIC (2 << 6) |
| 49 | |
| 50 | /* TGCR bit definitions */ |
| 51 | #define TIM12RS_UNRESET (1 << 0) |
| 52 | #define TIM34RS_UNRESET (1 << 1) |
| 53 | #define TIMMODE_64BIT_WDOG (2 << 2) |
| 54 | |
| 55 | /* WDTCR bit definitions */ |
| 56 | #define WDEN (1 << 14) |
| 57 | #define WDFLAG (1 << 15) |
| 58 | #define WDKEY_SEQ0 (0xa5c6 << 16) |
| 59 | #define WDKEY_SEQ1 (0xda7e << 16) |
| 60 | |
| 61 | static int heartbeat = DEFAULT_HEARTBEAT; |
| 62 | |
Alexey Dobriyan | c7dfd0c | 2007-11-01 16:27:08 -0700 | [diff] [blame] | 63 | static DEFINE_SPINLOCK(io_lock); |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 64 | static unsigned long wdt_status; |
| 65 | #define WDT_IN_USE 0 |
| 66 | #define WDT_OK_TO_CLOSE 1 |
| 67 | #define WDT_REGION_INITED 2 |
| 68 | #define WDT_DEVICE_INITED 3 |
| 69 | |
| 70 | static struct resource *wdt_mem; |
| 71 | static void __iomem *wdt_base; |
| 72 | |
| 73 | static void wdt_service(void) |
| 74 | { |
| 75 | spin_lock(&io_lock); |
| 76 | |
| 77 | /* put watchdog in service state */ |
| 78 | davinci_writel(WDKEY_SEQ0, wdt_base + WDTCR); |
| 79 | /* put watchdog in active state */ |
| 80 | davinci_writel(WDKEY_SEQ1, wdt_base + WDTCR); |
| 81 | |
| 82 | spin_unlock(&io_lock); |
| 83 | } |
| 84 | |
| 85 | static void wdt_enable(void) |
| 86 | { |
| 87 | u32 tgcr; |
| 88 | u32 timer_margin; |
| 89 | |
| 90 | spin_lock(&io_lock); |
| 91 | |
| 92 | /* disable, internal clock source */ |
| 93 | davinci_writel(0, wdt_base + TCR); |
| 94 | /* reset timer, set mode to 64-bit watchdog, and unreset */ |
| 95 | davinci_writel(0, wdt_base + TGCR); |
| 96 | tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET; |
| 97 | davinci_writel(tgcr, wdt_base + TGCR); |
| 98 | /* clear counter regs */ |
| 99 | davinci_writel(0, wdt_base + TIM12); |
| 100 | davinci_writel(0, wdt_base + TIM34); |
| 101 | /* set timeout period */ |
| 102 | timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) & 0xffffffff); |
| 103 | davinci_writel(timer_margin, wdt_base + PRD12); |
| 104 | timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) >> 32); |
| 105 | davinci_writel(timer_margin, wdt_base + PRD34); |
| 106 | /* enable run continuously */ |
| 107 | davinci_writel(ENAMODE12_PERIODIC, wdt_base + TCR); |
| 108 | /* Once the WDT is in pre-active state write to |
| 109 | * TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are |
| 110 | * write protected (except for the WDKEY field) |
| 111 | */ |
| 112 | /* put watchdog in pre-active state */ |
| 113 | davinci_writel(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR); |
| 114 | /* put watchdog in active state */ |
| 115 | davinci_writel(WDKEY_SEQ1 | WDEN, wdt_base + WDTCR); |
| 116 | |
| 117 | spin_unlock(&io_lock); |
| 118 | } |
| 119 | |
| 120 | static int davinci_wdt_open(struct inode *inode, struct file *file) |
| 121 | { |
| 122 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) |
| 123 | return -EBUSY; |
| 124 | |
| 125 | wdt_enable(); |
| 126 | |
| 127 | return nonseekable_open(inode, file); |
| 128 | } |
| 129 | |
| 130 | static ssize_t |
| 131 | davinci_wdt_write(struct file *file, const char *data, size_t len, |
| 132 | loff_t *ppos) |
| 133 | { |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 134 | if (len) |
| 135 | wdt_service(); |
| 136 | |
| 137 | return len; |
| 138 | } |
| 139 | |
| 140 | static struct watchdog_info ident = { |
Wim Van Sebroeck | f1a08cc | 2007-07-20 21:47:55 +0000 | [diff] [blame] | 141 | .options = WDIOF_KEEPALIVEPING, |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 142 | .identity = "DaVinci Watchdog", |
| 143 | }; |
| 144 | |
Alan Cox | f78b0a8 | 2008-05-19 14:05:30 +0100 | [diff] [blame] | 145 | static long davinci_wdt_ioctl(struct file *file, |
| 146 | unsigned int cmd, unsigned long arg) |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 147 | { |
| 148 | int ret = -ENOTTY; |
| 149 | |
| 150 | switch (cmd) { |
| 151 | case WDIOC_GETSUPPORT: |
| 152 | ret = copy_to_user((struct watchdog_info *)arg, &ident, |
| 153 | sizeof(ident)) ? -EFAULT : 0; |
| 154 | break; |
| 155 | |
| 156 | case WDIOC_GETSTATUS: |
Wim Van Sebroeck | f1a08cc | 2007-07-20 21:47:55 +0000 | [diff] [blame] | 157 | case WDIOC_GETBOOTSTATUS: |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 158 | ret = put_user(0, (int *)arg); |
| 159 | break; |
| 160 | |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 161 | case WDIOC_KEEPALIVE: |
| 162 | wdt_service(); |
| 163 | ret = 0; |
| 164 | break; |
Wim Van Sebroeck | 0c06090 | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 165 | |
| 166 | case WDIOC_GETTIMEOUT: |
| 167 | ret = put_user(heartbeat, (int *)arg); |
| 168 | break; |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 169 | } |
| 170 | return ret; |
| 171 | } |
| 172 | |
| 173 | static int davinci_wdt_release(struct inode *inode, struct file *file) |
| 174 | { |
| 175 | wdt_service(); |
| 176 | clear_bit(WDT_IN_USE, &wdt_status); |
| 177 | |
| 178 | return 0; |
| 179 | } |
| 180 | |
| 181 | static const struct file_operations davinci_wdt_fops = { |
| 182 | .owner = THIS_MODULE, |
| 183 | .llseek = no_llseek, |
| 184 | .write = davinci_wdt_write, |
Alan Cox | f78b0a8 | 2008-05-19 14:05:30 +0100 | [diff] [blame] | 185 | .unlocked_ioctl = davinci_wdt_ioctl, |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 186 | .open = davinci_wdt_open, |
| 187 | .release = davinci_wdt_release, |
| 188 | }; |
| 189 | |
| 190 | static struct miscdevice davinci_wdt_miscdev = { |
| 191 | .minor = WATCHDOG_MINOR, |
| 192 | .name = "watchdog", |
| 193 | .fops = &davinci_wdt_fops, |
| 194 | }; |
| 195 | |
| 196 | static int davinci_wdt_probe(struct platform_device *pdev) |
| 197 | { |
| 198 | int ret = 0, size; |
| 199 | struct resource *res; |
| 200 | |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 201 | if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) |
| 202 | heartbeat = DEFAULT_HEARTBEAT; |
| 203 | |
| 204 | printk(KERN_INFO MODULE_NAME |
| 205 | "DaVinci Watchdog Timer: heartbeat %d sec\n", heartbeat); |
| 206 | |
| 207 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 208 | if (res == NULL) { |
| 209 | printk(KERN_INFO MODULE_NAME |
| 210 | "failed to get memory region resource\n"); |
| 211 | return -ENOENT; |
| 212 | } |
| 213 | |
| 214 | size = res->end - res->start + 1; |
| 215 | wdt_mem = request_mem_region(res->start, size, pdev->name); |
| 216 | |
| 217 | if (wdt_mem == NULL) { |
| 218 | printk(KERN_INFO MODULE_NAME "failed to get memory region\n"); |
| 219 | return -ENOENT; |
| 220 | } |
| 221 | wdt_base = (void __iomem *)(res->start); |
| 222 | |
| 223 | ret = misc_register(&davinci_wdt_miscdev); |
| 224 | if (ret < 0) { |
| 225 | printk(KERN_ERR MODULE_NAME "cannot register misc device\n"); |
| 226 | release_resource(wdt_mem); |
| 227 | kfree(wdt_mem); |
| 228 | } else { |
| 229 | set_bit(WDT_DEVICE_INITED, &wdt_status); |
| 230 | } |
| 231 | |
| 232 | return ret; |
| 233 | } |
| 234 | |
| 235 | static int davinci_wdt_remove(struct platform_device *pdev) |
| 236 | { |
| 237 | misc_deregister(&davinci_wdt_miscdev); |
| 238 | if (wdt_mem) { |
| 239 | release_resource(wdt_mem); |
| 240 | kfree(wdt_mem); |
| 241 | wdt_mem = NULL; |
| 242 | } |
| 243 | return 0; |
| 244 | } |
| 245 | |
| 246 | static struct platform_driver platform_wdt_driver = { |
| 247 | .driver = { |
| 248 | .name = "watchdog", |
Kay Sievers | f37d193 | 2008-04-10 21:29:23 -0700 | [diff] [blame] | 249 | .owner = THIS_MODULE, |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 250 | }, |
| 251 | .probe = davinci_wdt_probe, |
| 252 | .remove = davinci_wdt_remove, |
| 253 | }; |
| 254 | |
| 255 | static int __init davinci_wdt_init(void) |
| 256 | { |
| 257 | return platform_driver_register(&platform_wdt_driver); |
| 258 | } |
| 259 | |
| 260 | static void __exit davinci_wdt_exit(void) |
| 261 | { |
Florian Fainelli | bb0a38d | 2007-10-17 15:42:22 +0200 | [diff] [blame] | 262 | platform_driver_unregister(&platform_wdt_driver); |
Vladimir Barinov | 7d831bf | 2007-06-12 18:09:50 +0400 | [diff] [blame] | 263 | } |
| 264 | |
| 265 | module_init(davinci_wdt_init); |
| 266 | module_exit(davinci_wdt_exit); |
| 267 | |
| 268 | MODULE_AUTHOR("Texas Instruments"); |
| 269 | MODULE_DESCRIPTION("DaVinci Watchdog Driver"); |
| 270 | |
| 271 | module_param(heartbeat, int, 0); |
| 272 | MODULE_PARM_DESC(heartbeat, |
| 273 | "Watchdog heartbeat period in seconds from 1 to " |
| 274 | __MODULE_STRING(MAX_HEARTBEAT) ", default " |
| 275 | __MODULE_STRING(DEFAULT_HEARTBEAT)); |
| 276 | |
| 277 | MODULE_LICENSE("GPL"); |
| 278 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
Kay Sievers | f37d193 | 2008-04-10 21:29:23 -0700 | [diff] [blame] | 279 | MODULE_ALIAS("platform:watchdog"); |