diff options
Diffstat (limited to 'drivers/watchdog/ts72xx_wdt.c')
| -rw-r--r-- | drivers/watchdog/ts72xx_wdt.c | 521 |
1 files changed, 521 insertions, 0 deletions
diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c new file mode 100644 index 000000000000..458c499c1223 --- /dev/null +++ b/drivers/watchdog/ts72xx_wdt.c @@ -0,0 +1,521 @@ +/* + * Watchdog driver for Technologic Systems TS-72xx based SBCs + * (TS-7200, TS-7250 and TS-7260). These boards have external + * glue logic CPLD chip, which includes programmable watchdog + * timer. + * + * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi> + * + * This driver is based on ep93xx_wdt and wm831x_wdt drivers. + * + * 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/fs.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/miscdevice.h> +#include <linux/mutex.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/watchdog.h> +#include <linux/uaccess.h> + +#define TS72XX_WDT_FEED_VAL 0x05 +#define TS72XX_WDT_DEFAULT_TIMEOUT 8 + +static int timeout = TS72XX_WDT_DEFAULT_TIMEOUT; +module_param(timeout, int, 0); +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. " + "(1 <= timeout <= 8, default=" + __MODULE_STRING(TS72XX_WDT_DEFAULT_TIMEOUT) + ")"); + +static int nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, int, 0); +MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); + +/** + * struct ts72xx_wdt - watchdog control structure + * @lock: lock that protects this structure + * @regval: watchdog timeout value suitable for control register + * @flags: flags controlling watchdog device state + * @control_reg: watchdog control register + * @feed_reg: watchdog feed register + * @pdev: back pointer to platform dev + */ +struct ts72xx_wdt { + struct mutex lock; + int regval; + +#define TS72XX_WDT_BUSY_FLAG 1 +#define TS72XX_WDT_EXPECT_CLOSE_FLAG 2 + int flags; + + void __iomem *control_reg; + void __iomem *feed_reg; + + struct platform_device *pdev; +}; + +struct platform_device *ts72xx_wdt_pdev; + +/* + * TS-72xx Watchdog supports following timeouts (value written + * to control register): + * value description + * ------------------------- + * 0x00 watchdog disabled + * 0x01 250ms + * 0x02 500ms + * 0x03 1s + * 0x04 reserved + * 0x05 2s + * 0x06 4s + * 0x07 8s + * + * Timeouts below 1s are not very usable so we don't + * allow them at all. + * + * We provide two functions that convert between these: + * timeout_to_regval() and regval_to_timeout(). + */ +static const struct { + int timeout; + int regval; +} ts72xx_wdt_map[] = { + { 1, 3 }, + { 2, 5 }, + { 4, 6 }, + { 8, 7 }, +}; + +/** + * timeout_to_regval() - converts given timeout to control register value + * @new_timeout: timeout in seconds to be converted + * + * Function converts given @new_timeout into valid value that can + * be programmed into watchdog control register. When conversion is + * not possible, function returns %-EINVAL. + */ +static int timeout_to_regval(int new_timeout) +{ + int i; + + /* first limit it to 1 - 8 seconds */ + new_timeout = clamp_val(new_timeout, 1, 8); + + for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) { + if (ts72xx_wdt_map[i].timeout >= new_timeout) + return ts72xx_wdt_map[i].regval; + } + + return -EINVAL; +} + +/** + * regval_to_timeout() - converts control register value to timeout + * @regval: control register value to be converted + * + * Function converts given @regval to timeout in seconds (1, 2, 4 or 8). + * If @regval cannot be converted, function returns %-EINVAL. + */ +static int regval_to_timeout(int regval) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) { + if (ts72xx_wdt_map[i].regval == regval) + return ts72xx_wdt_map[i].timeout; + } + + return -EINVAL; +} + +/** + * ts72xx_wdt_kick() - kick the watchdog + * @wdt: watchdog to be kicked + * + * Called with @wdt->lock held. + */ +static inline void ts72xx_wdt_kick(struct ts72xx_wdt *wdt) +{ + __raw_writeb(TS72XX_WDT_FEED_VAL, wdt->feed_reg); +} + +/** + * ts72xx_wdt_start() - starts the watchdog timer + * @wdt: watchdog to be started + * + * This function programs timeout to watchdog timer + * and starts it. + * + * Called with @wdt->lock held. + */ +static void ts72xx_wdt_start(struct ts72xx_wdt *wdt) +{ + /* + * To program the wdt, it first must be "fed" and + * only after that (within 30 usecs) the configuration + * can be changed. + */ + ts72xx_wdt_kick(wdt); + __raw_writeb((u8)wdt->regval, wdt->control_reg); +} + +/** + * ts72xx_wdt_stop() - stops the watchdog timer + * @wdt: watchdog to be stopped + * + * Called with @wdt->lock held. + */ +static void ts72xx_wdt_stop(struct ts72xx_wdt *wdt) +{ + ts72xx_wdt_kick(wdt); + __raw_writeb(0, wdt->control_reg); +} + +static int ts72xx_wdt_open(struct inode *inode, struct file *file) +{ + struct ts72xx_wdt *wdt = platform_get_drvdata(ts72xx_wdt_pdev); + int regval; + + /* + * Try to convert default timeout to valid register + * value first. + */ + regval = timeout_to_regval(timeout); + if (regval < 0) { + dev_err(&wdt->pdev->dev, + "failed to convert timeout (%d) to register value\n", + timeout); + return -EINVAL; + } + + if (mutex_lock_interruptible(&wdt->lock)) + return -ERESTARTSYS; + + if ((wdt->flags & TS72XX_WDT_BUSY_FLAG) != 0) { + mutex_unlock(&wdt->lock); + return -EBUSY; + } + + wdt->flags = TS72XX_WDT_BUSY_FLAG; + wdt->regval = regval; + file->private_data = wdt; + + ts72xx_wdt_start(wdt); + + mutex_unlock(&wdt->lock); + return nonseekable_open(inode, file); +} + +static int ts72xx_wdt_release(struct inode *inode, struct file *file) +{ + struct ts72xx_wdt *wdt = file->private_data; + + if (mutex_lock_interruptible(&wdt->lock)) + return -ERESTARTSYS; + + if ((wdt->flags & TS72XX_WDT_EXPECT_CLOSE_FLAG) != 0) { + ts72xx_wdt_stop(wdt); + } else { + dev_warn(&wdt->pdev->dev, + "TS-72XX WDT device closed unexpectly. " + "Watchdog timer will not stop!\n"); + /* + * Kick it one more time, to give userland some time + * to recover (for example, respawning the kicker + * daemon). + */ + ts72xx_wdt_kick(wdt); + } + + wdt->flags = 0; + + mutex_unlock(&wdt->lock); + return 0; +} + +static ssize_t ts72xx_wdt_write(struct file *file, + const char __user *data, + size_t len, + loff_t *ppos) +{ + struct ts72xx_wdt *wdt = file->private_data; + + if (!len) + return 0; + + if (mutex_lock_interruptible(&wdt->lock)) + return -ERESTARTSYS; + + ts72xx_wdt_kick(wdt); + + /* + * Support for magic character closing. User process + * writes 'V' into the device, just before it is closed. + * This means that we know that the wdt timer can be + * stopped after user closes the device. + */ + if (!nowayout) { + int i; + + for (i = 0; i < len; i++) { + char c; + + /* In case it was set long ago */ + wdt->flags &= ~TS72XX_WDT_EXPECT_CLOSE_FLAG; + + if (get_user(c, data + i)) { + mutex_unlock(&wdt->lock); + return -EFAULT; + } + if (c == 'V') { + wdt->flags |= TS72XX_WDT_EXPECT_CLOSE_FLAG; + break; + } + } + } + + mutex_unlock(&wdt->lock); + return len; +} + +static const struct watchdog_info winfo = { + .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | + WDIOF_MAGICCLOSE, + .firmware_version = 1, + .identity = "TS-72XX WDT", +}; + +static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct ts72xx_wdt *wdt = file->private_data; + void __user *argp = (void __user *)arg; + int __user *p = (int __user *)argp; + int error = 0; + + if (mutex_lock_interruptible(&wdt->lock)) + return -ERESTARTSYS; + + switch (cmd) { + case WDIOC_GETSUPPORT: + error = copy_to_user(argp, &winfo, sizeof(winfo)); + break; + + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, p); + + case WDIOC_KEEPALIVE: + ts72xx_wdt_kick(wdt); + break; + + case WDIOC_SETOPTIONS: { + int options; + + if (get_user(options, p)) { + error = -EFAULT; + break; + } + + error = -EINVAL; + + if ((options & WDIOS_DISABLECARD) != 0) { + ts72xx_wdt_stop(wdt); + error = 0; + } + if ((options & WDIOS_ENABLECARD) != 0) { + ts72xx_wdt_start(wdt); + error = 0; + } + + break; + } + + case WDIOC_SETTIMEOUT: { + int new_timeout; + + if (get_user(new_timeout, p)) { + error = -EFAULT; + } else { + int regval; + + regval = timeout_to_regval(new_timeout); + if (regval < 0) { + error = -EINVAL; + } else { + ts72xx_wdt_stop(wdt); + wdt->regval = regval; + ts72xx_wdt_start(wdt); + } + } + if (error) + break; + + /*FALLTHROUGH*/ + } + + case WDIOC_GETTIMEOUT: + if (put_user(regval_to_timeout(wdt->regval), p)) + error = -EFAULT; + break; + + default: + error = -ENOTTY; + break; + } + + mutex_unlock(&wdt->lock); + return error; +} + +static const struct file_operations ts72xx_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .open = ts72xx_wdt_open, + .release = ts72xx_wdt_release, + .write = ts72xx_wdt_write, + .unlocked_ioctl = ts72xx_wdt_ioctl, +}; + +static struct miscdevice ts72xx_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &ts72xx_wdt_fops, +}; + +static __devinit int ts72xx_wdt_probe(struct platform_device *pdev) +{ + struct ts72xx_wdt *wdt; + struct resource *r1, *r2; + int error = 0; + + wdt = kzalloc(sizeof(struct ts72xx_wdt), GFP_KERNEL); + if (!wdt) { + dev_err(&pdev->dev, "failed to allocate memory\n"); + return -ENOMEM; + } + + r1 = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!r1) { + dev_err(&pdev->dev, "failed to get memory resource\n"); + error = -ENODEV; + goto fail; + } + + r1 = request_mem_region(r1->start, resource_size(r1), pdev->name); + if (!r1) { + dev_err(&pdev->dev, "cannot request memory region\n"); + error = -EBUSY; + goto fail; + } + + wdt->control_reg = ioremap(r1->start, resource_size(r1)); + if (!wdt->control_reg) { + dev_err(&pdev->dev, "failed to map memory\n"); + error = -ENODEV; + goto fail_free_control; + } + + r2 = platform_get_resource(pdev, IORESOURCE_MEM, 1); + if (!r2) { + dev_err(&pdev->dev, "failed to get memory resource\n"); + error = -ENODEV; + goto fail_unmap_control; + } + + r2 = request_mem_region(r2->start, resource_size(r2), pdev->name); + if (!r2) { + dev_err(&pdev->dev, "cannot request memory region\n"); + error = -EBUSY; + goto fail_unmap_control; + } + + wdt->feed_reg = ioremap(r2->start, resource_size(r2)); + if (!wdt->feed_reg) { + dev_err(&pdev->dev, "failed to map memory\n"); + error = -ENODEV; + goto fail_free_feed; + } + + platform_set_drvdata(pdev, wdt); + ts72xx_wdt_pdev = pdev; + wdt->pdev = pdev; + mutex_init(&wdt->lock); + + error = misc_register(&ts72xx_wdt_miscdev); + if (error) { + dev_err(&pdev->dev, "failed to register miscdev\n"); + goto fail_unmap_feed; + } + + dev_info(&pdev->dev, "TS-72xx Watchdog driver\n"); + + return 0; + +fail_unmap_feed: + platform_set_drvdata(pdev, NULL); + iounmap(wdt->feed_reg); +fail_free_feed: + release_mem_region(r2->start, resource_size(r2)); +fail_unmap_control: + iounmap(wdt->control_reg); +fail_free_control: + release_mem_region(r1->start, resource_size(r1)); +fail: + kfree(wdt); + return error; +} + +static __devexit int ts72xx_wdt_remove(struct platform_device *pdev) +{ + struct ts72xx_wdt *wdt = platform_get_drvdata(pdev); + struct resource *res; + int error; + + error = misc_deregister(&ts72xx_wdt_miscdev); + platform_set_drvdata(pdev, NULL); + + iounmap(wdt->feed_reg); + res = platform_get_resource(pdev, IORESOURCE_MEM, 1); + release_mem_region(res->start, resource_size(res)); + + iounmap(wdt->control_reg); + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + release_mem_region(res->start, resource_size(res)); + + kfree(wdt); + return error; +} + +static struct platform_driver ts72xx_wdt_driver = { + .probe = ts72xx_wdt_probe, + .remove = __devexit_p(ts72xx_wdt_remove), + .driver = { + .name = "ts72xx-wdt", + .owner = THIS_MODULE, + }, +}; + +static __init int ts72xx_wdt_init(void) +{ + return platform_driver_register(&ts72xx_wdt_driver); +} +module_init(ts72xx_wdt_init); + +static __exit void ts72xx_wdt_exit(void) +{ + platform_driver_unregister(&ts72xx_wdt_driver); +} +module_exit(ts72xx_wdt_exit); + +MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>"); +MODULE_DESCRIPTION("TS-72xx SBC Watchdog"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:ts72xx-wdt"); |