--- /dev/null
+/*
+ * 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)
+{
+ /* Can't seek (pwrite) on this device */
+ if (ppos != &file->f_pos)
+ return -ESPIPE;
+
+ if (len)
+ wdt_service();
+
+ return len;
+}
+
+static struct watchdog_info ident = {
+ .options = WDIOF_CARDRESET | 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:
+ 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);
projects / karo-tx-linux.git / commitdiff