[PATCH v2 1/2] ep93xx: implemented watchdog timer driver for TS-72xx SBCs
Mika Westerberg
mika.westerberg at iki.fi
Sun Dec 6 04:38:58 EST 2009
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 at iki.fi>
---
drivers/watchdog/Kconfig | 11 +
drivers/watchdog/Makefile | 1 +
drivers/watchdog/ts72xx_wdt.c | 516 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 528 insertions(+), 0 deletions(-)
create mode 100644 drivers/watchdog/ts72xx_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 3711b88..5204612 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -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
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 699199b..8e8a9b4 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -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
index 0000000..c4a4d37
--- /dev/null
+++ b/drivers/watchdog/ts72xx_wdt.c
@@ -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 at 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 at iki.fi>");
+MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ts72xx-wdt");
--
1.5.6.5
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