[WATCHDOG] ep93xx: implemented watchdog timer driver for TS-72xx SBCs
Mika Westerberg [Sun, 29 Nov 2009 14:58:38 +0000 (16:58 +0200)]
Technologic Systems TS-72xx SBCs have external glue logic
CPLD which includes watchdog timer. This driver implements
kernel support for that.

Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig
drivers/watchdog/Makefile
drivers/watchdog/ts72xx_wdt.c [new file with mode: 0644]

index 3da3f48..1e48d4c 100644 (file)
@@ -289,6 +289,17 @@ config ADX_WATCHDOG
          Say Y here if you want support for the watchdog timer on Avionic
          Design Xanthos boards.
 
+config TS72XX_WATCHDOG
+       tristate "TS-72XX SBC Watchdog"
+       depends on MACH_TS72XX
+       help
+         Technologic Systems TS-7200, TS-7250 and TS-7260 boards have
+         watchdog timer implemented in a external CPLD chip. Say Y here
+         if you want to support for the watchdog timer on TS-72XX boards.
+
+         To compile this driver as a module, choose M here: the
+         module will be called ts72xx_wdt.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
index 475c611..2fd1594 100644 (file)
@@ -46,6 +46,7 @@ obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
 obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
 obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
 obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
+obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
new file mode 100644 (file)
index 0000000..c4a4d37
--- /dev/null
@@ -0,0 +1,516 @@
+/*
+ * 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/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_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->control_reg);
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       release_mem_region(res->start, resource_size(res));
+
+       iounmap(wdt->feed_reg);
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+       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");