--- /dev/null
+/*
+* of_xilinx_wdt.c 1.01 A Watchdog Device Driver for Xilinx xps_timebase_wdt
+*
+* (C) Copyright 2011 (Alejandro Cabrera <aldaya@gmail.com>)
+*
+* -----------------------
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License
+* as published by the Free Software Foundation; either version
+* 2 of the License, or (at your option) any later version.
+*
+* -----------------------
+* 30-May-2011 Alejandro Cabrera <aldaya@gmail.com>
+* - If "xlnx,wdt-enable-once" wasn't found on device tree the
+* module will use CONFIG_WATCHDOG_NOWAYOUT
+* - If the device tree parameters ("clock-frequency" and
+* "xlnx,wdt-interval") wasn't found the driver won't
+* know the wdt reset interval
+*/
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/watchdog.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+
+/* Register offsets for the Wdt device */
+#define XWT_TWCSR0_OFFSET 0x0 /* Control/Status Register0 */
+#define XWT_TWCSR1_OFFSET 0x4 /* Control/Status Register1 */
+#define XWT_TBR_OFFSET 0x8 /* Timebase Register Offset */
+
+/* Control/Status Register Masks */
+#define XWT_CSR0_WRS_MASK 0x00000008 /* Reset status */
+#define XWT_CSR0_WDS_MASK 0x00000004 /* Timer state */
+#define XWT_CSR0_EWDT1_MASK 0x00000002 /* Enable bit 1 */
+
+/* Control/Status Register 0/1 bits */
+#define XWT_CSRX_EWDT2_MASK 0x00000001 /* Enable bit 2 */
+
+/* SelfTest constants */
+#define XWT_MAX_SELFTEST_LOOP_COUNT 0x00010000
+#define XWT_TIMER_FAILED 0xFFFFFFFF
+
+#define WATCHDOG_NAME "Xilinx Watchdog"
+#define PFX WATCHDOG_NAME ": "
+
+struct xwdt_device {
+ struct resource res;
+ void __iomem *base;
+ u32 nowayout;
+ u32 wdt_interval;
+ u32 boot_status;
+};
+
+static struct xwdt_device xdev;
+
+static u32 timeout;
+static u32 control_status_reg;
+static u8 expect_close;
+static u8 no_timeout;
+static unsigned long driver_open;
+
+static DEFINE_SPINLOCK(spinlock);
+
+static void xwdt_start(void)
+{
+ spin_lock(&spinlock);
+
+ /* Clean previous status and enable the watchdog timer */
+ control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET);
+ control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK);
+
+ iowrite32((control_status_reg | XWT_CSR0_EWDT1_MASK),
+ xdev.base + XWT_TWCSR0_OFFSET);
+
+ iowrite32(XWT_CSRX_EWDT2_MASK, xdev.base + XWT_TWCSR1_OFFSET);
+
+ spin_unlock(&spinlock);
+}
+
+static void xwdt_stop(void)
+{
+ spin_lock(&spinlock);
+
+ control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET);
+
+ iowrite32((control_status_reg & ~XWT_CSR0_EWDT1_MASK),
+ xdev.base + XWT_TWCSR0_OFFSET);
+
+ iowrite32(0, xdev.base + XWT_TWCSR1_OFFSET);
+
+ spin_unlock(&spinlock);
+ printk(KERN_INFO PFX "Stopped!\n");
+}
+
+static void xwdt_keepalive(void)
+{
+ spin_lock(&spinlock);
+
+ control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET);
+ control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK);
+ iowrite32(control_status_reg, xdev.base + XWT_TWCSR0_OFFSET);
+
+ spin_unlock(&spinlock);
+}
+
+static void xwdt_get_status(int *status)
+{
+ int new_status;
+
+ spin_lock(&spinlock);
+
+ control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET);
+ new_status = ((control_status_reg &
+ (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK)) != 0);
+ spin_unlock(&spinlock);
+
+ *status = 0;
+ if (new_status & 1)
+ *status |= WDIOF_CARDRESET;
+}
+
+static u32 xwdt_selftest(void)
+{
+ int i;
+ u32 timer_value1;
+ u32 timer_value2;
+
+ spin_lock(&spinlock);
+
+ timer_value1 = ioread32(xdev.base + XWT_TBR_OFFSET);
+ timer_value2 = ioread32(xdev.base + XWT_TBR_OFFSET);
+
+ for (i = 0;
+ ((i <= XWT_MAX_SELFTEST_LOOP_COUNT) &&
+ (timer_value2 == timer_value1)); i++) {
+ timer_value2 = ioread32(xdev.base + XWT_TBR_OFFSET);
+ }
+
+ spin_unlock(&spinlock);
+
+ if (timer_value2 != timer_value1)
+ return ~XWT_TIMER_FAILED;
+ else
+ return XWT_TIMER_FAILED;
+}
+
+static int xwdt_open(struct inode *inode, struct file *file)
+{
+ /* Only one process can handle the wdt at a time */
+ if (test_and_set_bit(0, &driver_open))
+ return -EBUSY;
+
+ /* Make sure that the module are always loaded...*/
+ if (xdev.nowayout)
+ __module_get(THIS_MODULE);
+
+ xwdt_start();
+ printk(KERN_INFO PFX "Started...\n");
+
+ return nonseekable_open(inode, file);
+}
+
+static int xwdt_release(struct inode *inode, struct file *file)
+{
+ if (expect_close == 42) {
+ xwdt_stop();
+ } else {
+ printk(KERN_CRIT PFX
+ "Unexpected close, not stopping watchdog!\n");
+ xwdt_keepalive();
+ }
+
+ clear_bit(0, &driver_open);
+ expect_close = 0;
+ return 0;
+}
+
+/*
+ * xwdt_write:
+ * @file: file handle to the watchdog
+ * @buf: buffer to write (unused as data does not matter here
+ * @count: count of bytes
+ * @ppos: pointer to the position to write. No seeks allowed
+ *
+ * A write to a watchdog device is defined as a keepalive signal. Any
+ * write of data will do, as we don't define content meaning.
+ */
+static ssize_t xwdt_write(struct file *file, const char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ if (len) {
+ if (!xdev.nowayout) {
+ size_t i;
+
+ /* In case it was set long ago */
+ expect_close = 0;
+
+ for (i = 0; i != len; i++) {
+ char c;
+
+ if (get_user(c, buf + i))
+ return -EFAULT;
+ if (c == 'V')
+ expect_close = 42;
+ }
+ }
+ xwdt_keepalive();
+ }
+ return len;
+}
+
+static const struct watchdog_info ident = {
+ .options = WDIOF_MAGICCLOSE |
+ WDIOF_KEEPALIVEPING,
+ .firmware_version = 1,
+ .identity = WATCHDOG_NAME,
+};
+
+/*
+ * xwdt_ioctl:
+ * @file: file handle to the device
+ * @cmd: watchdog command
+ * @arg: argument pointer
+ *
+ * The watchdog API defines a common set of functions for all watchdogs
+ * according to their available features.
+ */
+static long xwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ int status;
+
+ union {
+ struct watchdog_info __user *ident;
+ int __user *i;
+ } uarg;
+
+ uarg.i = (int __user *)arg;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(uarg.ident, &ident,
+ sizeof(ident)) ? -EFAULT : 0;
+
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(xdev.boot_status, uarg.i);
+
+ case WDIOC_GETSTATUS:
+ xwdt_get_status(&status);
+ return put_user(status, uarg.i);
+
+ case WDIOC_KEEPALIVE:
+ xwdt_keepalive();
+ return 0;
+
+ case WDIOC_GETTIMEOUT:
+ if (no_timeout)
+ return -ENOTTY;
+ else
+ return put_user(timeout, uarg.i);
+
+ default:
+ return -ENOTTY;
+ }
+}
+
+static const struct file_operations xwdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = xwdt_write,
+ .open = xwdt_open,
+ .release = xwdt_release,
+ .unlocked_ioctl = xwdt_ioctl,
+};
+
+static struct miscdevice xwdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &xwdt_fops,
+};
+
+static int __devinit xwdt_probe(struct platform_device *pdev)
+{
+ int rc;
+ u32 *tmptr;
+ u32 *pfreq;
+
+ no_timeout = 0;
+
+ pfreq = (u32 *)of_get_property(pdev->dev.of_node->parent,
+ "clock-frequency", NULL);
+
+ if (pfreq == NULL) {
+ printk(KERN_WARNING PFX
+ "The watchdog clock frequency cannot be obtained!\n");
+ no_timeout = 1;
+ }
+
+ rc = of_address_to_resource(pdev->dev.of_node, 0, &xdev.res);
+ if (rc) {
+ printk(KERN_WARNING PFX "invalid address!\n");
+ return rc;
+ }
+
+ tmptr = (u32 *)of_get_property(pdev->dev.of_node,
+ "xlnx,wdt-interval", NULL);
+ if (tmptr == NULL) {
+ printk(KERN_WARNING PFX "Parameter \"xlnx,wdt-interval\""
+ " not found in device tree!\n");
+ no_timeout = 1;
+ } else {
+ xdev.wdt_interval = *tmptr;
+ }
+
+ tmptr = (u32 *)of_get_property(pdev->dev.of_node,
+ "xlnx,wdt-enable-once", NULL);
+ if (tmptr == NULL) {
+ printk(KERN_WARNING PFX "Parameter \"xlnx,wdt-enable-once\""
+ " not found in device tree!\n");
+ xdev.nowayout = WATCHDOG_NOWAYOUT;
+ }
+
+/*
+ * Twice of the 2^wdt_interval / freq because the first wdt overflow is
+ * ignored (interrupt), reset is only generated at second wdt overflow
+ */
+ if (!no_timeout)
+ timeout = 2 * ((1<<xdev.wdt_interval) / *pfreq);
+
+ if (!request_mem_region(xdev.res.start,
+ xdev.res.end - xdev.res.start + 1, WATCHDOG_NAME)) {
+ rc = -ENXIO;
+ printk(KERN_ERR PFX "memory request failure!\n");
+ goto err_out;
+ }
+
+ xdev.base = ioremap(xdev.res.start, xdev.res.end - xdev.res.start + 1);
+ if (xdev.base == NULL) {
+ rc = -ENOMEM;
+ printk(KERN_ERR PFX "ioremap failure!\n");
+ goto release_mem;
+ }
+
+ rc = xwdt_selftest();
+ if (rc == XWT_TIMER_FAILED) {
+ printk(KERN_ERR PFX "SelfTest routine error!\n");
+ goto unmap_io;
+ }
+
+ xwdt_get_status(&xdev.boot_status);
+
+ rc = misc_register(&xwdt_miscdev);
+ if (rc) {
+ printk(KERN_ERR PFX
+ "cannot register miscdev on minor=%d (err=%d)\n",
+ xwdt_miscdev.minor, rc);
+ goto unmap_io;
+ }
+
+ if (no_timeout)
+ printk(KERN_INFO PFX
+ "driver loaded (timeout=? sec, nowayout=%d)\n",
+ xdev.nowayout);
+ else
+ printk(KERN_INFO PFX
+ "driver loaded (timeout=%d sec, nowayout=%d)\n",
+ timeout, xdev.nowayout);
+
+ expect_close = 0;
+ clear_bit(0, &driver_open);
+
+ return 0;
+
+unmap_io:
+ iounmap(xdev.base);
+release_mem:
+ release_mem_region(xdev.res.start, resource_size(&xdev.res));
+err_out:
+ return rc;
+}
+
+static int __devexit xwdt_remove(struct platform_device *dev)
+{
+ misc_deregister(&xwdt_miscdev);
+ iounmap(xdev.base);
+ release_mem_region(xdev.res.start, resource_size(&xdev.res));
+
+ return 0;
+}
+
+/* Match table for of_platform binding */
+static struct of_device_id __devinitdata xwdt_of_match[] = {
+ { .compatible = "xlnx,xps-timebase-wdt-1.01.a", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, xwdt_of_match);
+
+static struct platform_driver xwdt_driver = {
+ .probe = xwdt_probe,
+ .remove = __devexit_p(xwdt_remove),
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = WATCHDOG_NAME,
+ .of_match_table = xwdt_of_match,
+ },
+};
+
+static int __init xwdt_init(void)
+{
+ return platform_driver_register(&xwdt_driver);
+}
+
+static void __exit xwdt_exit(void)
+{
+ platform_driver_unregister(&xwdt_driver);
+}
+
+module_init(xwdt_init);
+module_exit(xwdt_exit);
+
+MODULE_AUTHOR("Alejandro Cabrera <aldaya@gmail.com>");
+MODULE_DESCRIPTION("Xilinx Watchdog driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
projects / karo-tx-linux.git / commitdiff