diff options
Diffstat (limited to 'drivers/watchdog/davinci_wdt.c')
| -rw-r--r-- | drivers/watchdog/davinci_wdt.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c new file mode 100644 index 000000000000..19db5302ba6e --- /dev/null +++ b/drivers/watchdog/davinci_wdt.c @@ -0,0 +1,281 @@ +/* + * drivers/char/watchdog/davinci_wdt.c + * + * Watchdog driver for DaVinci DM644x/DM646x processors + * + * Copyright (C) 2006 Texas Instruments. + * + * 2007 (c) MontaVista Software, Inc. This file is licensed under + * the terms of the GNU General Public License version 2. This program + * is licensed "as is" without any warranty of any kind, whether express + * or implied. + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/init.h> +#include <linux/bitops.h> +#include <linux/platform_device.h> +#include <linux/spinlock.h> + +#include <asm/hardware.h> +#include <asm/uaccess.h> +#include <asm/io.h> + +#define MODULE_NAME "DAVINCI-WDT: " + +#define DEFAULT_HEARTBEAT 60 +#define MAX_HEARTBEAT 600 /* really the max margin is 264/27MHz*/ + +/* Timer register set definition */ +#define PID12 (0x0) +#define EMUMGT (0x4) +#define TIM12 (0x10) +#define TIM34 (0x14) +#define PRD12 (0x18) +#define PRD34 (0x1C) +#define TCR (0x20) +#define TGCR (0x24) +#define WDTCR (0x28) + +/* TCR bit definitions */ +#define ENAMODE12_DISABLED (0 << 6) +#define ENAMODE12_ONESHOT (1 << 6) +#define ENAMODE12_PERIODIC (2 << 6) + +/* TGCR bit definitions */ +#define TIM12RS_UNRESET (1 << 0) +#define TIM34RS_UNRESET (1 << 1) +#define TIMMODE_64BIT_WDOG (2 << 2) + +/* WDTCR bit definitions */ +#define WDEN (1 << 14) +#define WDFLAG (1 << 15) +#define WDKEY_SEQ0 (0xa5c6 << 16) +#define WDKEY_SEQ1 (0xda7e << 16) + +static int heartbeat = DEFAULT_HEARTBEAT; + +static spinlock_t io_lock; +static unsigned long wdt_status; +#define WDT_IN_USE 0 +#define WDT_OK_TO_CLOSE 1 +#define WDT_REGION_INITED 2 +#define WDT_DEVICE_INITED 3 + +static struct resource *wdt_mem; +static void __iomem *wdt_base; + +static void wdt_service(void) +{ + spin_lock(&io_lock); + + /* put watchdog in service state */ + davinci_writel(WDKEY_SEQ0, wdt_base + WDTCR); + /* put watchdog in active state */ + davinci_writel(WDKEY_SEQ1, wdt_base + WDTCR); + + spin_unlock(&io_lock); +} + +static void wdt_enable(void) +{ + u32 tgcr; + u32 timer_margin; + + spin_lock(&io_lock); + + /* disable, internal clock source */ + davinci_writel(0, wdt_base + TCR); + /* reset timer, set mode to 64-bit watchdog, and unreset */ + davinci_writel(0, wdt_base + TGCR); + tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET; + davinci_writel(tgcr, wdt_base + TGCR); + /* clear counter regs */ + davinci_writel(0, wdt_base + TIM12); + davinci_writel(0, wdt_base + TIM34); + /* set timeout period */ + timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) & 0xffffffff); + davinci_writel(timer_margin, wdt_base + PRD12); + timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) >> 32); + davinci_writel(timer_margin, wdt_base + PRD34); + /* enable run continuously */ + davinci_writel(ENAMODE12_PERIODIC, wdt_base + TCR); + /* Once the WDT is in pre-active state write to + * TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are + * write protected (except for the WDKEY field) + */ + /* put watchdog in pre-active state */ + davinci_writel(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR); + /* put watchdog in active state */ + davinci_writel(WDKEY_SEQ1 | WDEN, wdt_base + WDTCR); + + spin_unlock(&io_lock); +} + +static int davinci_wdt_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(WDT_IN_USE, &wdt_status)) + return -EBUSY; + + wdt_enable(); + + return nonseekable_open(inode, file); +} + +static ssize_t +davinci_wdt_write(struct file *file, const char *data, size_t len, + loff_t *ppos) +{ + if (len) + wdt_service(); + + return len; +} + +static struct watchdog_info ident = { + .options = WDIOF_KEEPALIVEPING, + .identity = "DaVinci Watchdog", +}; + +static int +davinci_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, + unsigned long arg) +{ + int ret = -ENOTTY; + + switch (cmd) { + case WDIOC_GETSUPPORT: + ret = copy_to_user((struct watchdog_info *)arg, &ident, + sizeof(ident)) ? -EFAULT : 0; + break; + + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + ret = put_user(0, (int *)arg); + break; + + case WDIOC_GETTIMEOUT: + ret = put_user(heartbeat, (int *)arg); + break; + + case WDIOC_KEEPALIVE: + wdt_service(); + ret = 0; + break; + } + return ret; +} + +static int davinci_wdt_release(struct inode *inode, struct file *file) +{ + wdt_service(); + clear_bit(WDT_IN_USE, &wdt_status); + + return 0; +} + +static const struct file_operations davinci_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = davinci_wdt_write, + .ioctl = davinci_wdt_ioctl, + .open = davinci_wdt_open, + .release = davinci_wdt_release, +}; + +static struct miscdevice davinci_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &davinci_wdt_fops, +}; + +static int davinci_wdt_probe(struct platform_device *pdev) +{ + int ret = 0, size; + struct resource *res; + + spin_lock_init(&io_lock); + + if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) + heartbeat = DEFAULT_HEARTBEAT; + + printk(KERN_INFO MODULE_NAME + "DaVinci Watchdog Timer: heartbeat %d sec\n", heartbeat); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (res == NULL) { + printk(KERN_INFO MODULE_NAME + "failed to get memory region resource\n"); + return -ENOENT; + } + + size = res->end - res->start + 1; + wdt_mem = request_mem_region(res->start, size, pdev->name); + + if (wdt_mem == NULL) { + printk(KERN_INFO MODULE_NAME "failed to get memory region\n"); + return -ENOENT; + } + wdt_base = (void __iomem *)(res->start); + + ret = misc_register(&davinci_wdt_miscdev); + if (ret < 0) { + printk(KERN_ERR MODULE_NAME "cannot register misc device\n"); + release_resource(wdt_mem); + kfree(wdt_mem); + } else { + set_bit(WDT_DEVICE_INITED, &wdt_status); + } + + return ret; +} + +static int davinci_wdt_remove(struct platform_device *pdev) +{ + misc_deregister(&davinci_wdt_miscdev); + if (wdt_mem) { + release_resource(wdt_mem); + kfree(wdt_mem); + wdt_mem = NULL; + } + return 0; +} + +static struct platform_driver platform_wdt_driver = { + .driver = { + .name = "watchdog", + }, + .probe = davinci_wdt_probe, + .remove = davinci_wdt_remove, +}; + +static int __init davinci_wdt_init(void) +{ + return platform_driver_register(&platform_wdt_driver); +} + +static void __exit davinci_wdt_exit(void) +{ + return platform_driver_unregister(&platform_wdt_driver); +} + +module_init(davinci_wdt_init); +module_exit(davinci_wdt_exit); + +MODULE_AUTHOR("Texas Instruments"); +MODULE_DESCRIPTION("DaVinci Watchdog Driver"); + +module_param(heartbeat, int, 0); +MODULE_PARM_DESC(heartbeat, + "Watchdog heartbeat period in seconds from 1 to " + __MODULE_STRING(MAX_HEARTBEAT) ", default " + __MODULE_STRING(DEFAULT_HEARTBEAT)); + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |