--- /dev/null
+/*
+ * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
+ * JZ4740 Watchdog driver
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#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 <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/device.h>
+#include <linux/clk.h>
+#include <linux/slab.h>
+
+#include <asm/mach-jz4740/timer.h>
+
+#define JZ_REG_WDT_TIMER_DATA 0x0
+#define JZ_REG_WDT_COUNTER_ENABLE 0x4
+#define JZ_REG_WDT_TIMER_COUNTER 0x8
+#define JZ_REG_WDT_TIMER_CONTROL 0xC
+
+#define JZ_WDT_CLOCK_PCLK 0x1
+#define JZ_WDT_CLOCK_RTC 0x2
+#define JZ_WDT_CLOCK_EXT 0x4
+
+#define WDT_IN_USE 0
+#define WDT_OK_TO_CLOSE 1
+
+#define JZ_WDT_CLOCK_DIV_SHIFT 3
+
+#define JZ_WDT_CLOCK_DIV_1 (0 << JZ_WDT_CLOCK_DIV_SHIFT)
+#define JZ_WDT_CLOCK_DIV_4 (1 << JZ_WDT_CLOCK_DIV_SHIFT)
+#define JZ_WDT_CLOCK_DIV_16 (2 << JZ_WDT_CLOCK_DIV_SHIFT)
+#define JZ_WDT_CLOCK_DIV_64 (3 << JZ_WDT_CLOCK_DIV_SHIFT)
+#define JZ_WDT_CLOCK_DIV_256 (4 << JZ_WDT_CLOCK_DIV_SHIFT)
+#define JZ_WDT_CLOCK_DIV_1024 (5 << JZ_WDT_CLOCK_DIV_SHIFT)
+
+#define DEFAULT_HEARTBEAT 5
+#define MAX_HEARTBEAT 2048
+
+static struct {
+ void __iomem *base;
+ struct resource *mem;
+ struct clk *rtc_clk;
+ unsigned long status;
+} jz4740_wdt;
+
+static int heartbeat = DEFAULT_HEARTBEAT;
+
+
+static void jz4740_wdt_service(void)
+{
+ writew(0x0, jz4740_wdt.base + JZ_REG_WDT_TIMER_COUNTER);
+}
+
+static void jz4740_wdt_set_heartbeat(int new_heartbeat)
+{
+ unsigned int rtc_clk_rate;
+ unsigned int timeout_value;
+ unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
+
+ heartbeat = new_heartbeat;
+
+ rtc_clk_rate = clk_get_rate(jz4740_wdt.rtc_clk);
+
+ timeout_value = rtc_clk_rate * heartbeat;
+ while (timeout_value > 0xffff) {
+ if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
+ /* Requested timeout too high;
+ * use highest possible value. */
+ timeout_value = 0xffff;
+ break;
+ }
+ timeout_value >>= 2;
+ clock_div += (1 << JZ_WDT_CLOCK_DIV_SHIFT);
+ }
+
+ writeb(0x0, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
+ writew(clock_div, jz4740_wdt.base + JZ_REG_WDT_TIMER_CONTROL);
+
+ writew((u16)timeout_value, jz4740_wdt.base + JZ_REG_WDT_TIMER_DATA);
+ writew(0x0, jz4740_wdt.base + JZ_REG_WDT_TIMER_COUNTER);
+ writew(clock_div | JZ_WDT_CLOCK_RTC,
+ jz4740_wdt.base + JZ_REG_WDT_TIMER_CONTROL);
+
+ writeb(0x1, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
+}
+
+static void jz4740_wdt_enable(void)
+{
+ jz4740_timer_enable_watchdog();
+ jz4740_wdt_set_heartbeat(heartbeat);
+}
+
+static void jz4740_wdt_disable(void)
+{
+ jz4740_timer_disable_watchdog();
+ writeb(0x0, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
+}
+
+static int jz4740_wdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(WDT_IN_USE, &jz4740_wdt.status))
+ return -EBUSY;
+
+ jz4740_wdt_enable();
+
+ return nonseekable_open(inode, file);
+}
+
+static ssize_t jz4740_wdt_write(struct file *file, const char *data,
+ size_t len, loff_t *ppos)
+{
+ if (len) {
+ if (data[len-1] == 'V')
+ set_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status);
+ else
+ clear_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status);
+
+ jz4740_wdt_service();
+ }
+
+ return len;
+}
+
+static const struct watchdog_info ident = {
+ .options = WDIOF_KEEPALIVEPING,
+ .identity = "jz4740 Watchdog",
+};
+
+static long jz4740_wdt_ioctl(struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ int ret = -ENOTTY;
+ int heartbeat_seconds;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ ret = copy_to_user((struct watchdog_info *)arg, &ident,
+ sizeof(ident)) ? -EFAULT : 0;
+ break;
+
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ ret = put_user(0, (int *)arg);
+ break;
+
+ case WDIOC_KEEPALIVE:
+ jz4740_wdt_service();
+ return 0;
+
+ case WDIOC_SETTIMEOUT:
+ if (get_user(heartbeat_seconds, (int __user *)arg))
+ return -EFAULT;
+
+ jz4740_wdt_set_heartbeat(heartbeat_seconds);
+ return 0;
+
+ case WDIOC_GETTIMEOUT:
+ return put_user(heartbeat, (int *)arg);
+
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+static int jz4740_wdt_release(struct inode *inode, struct file *file)
+{
+ jz4740_wdt_service();
+
+ if (test_and_clear_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status))
+ jz4740_wdt_disable();
+
+ clear_bit(WDT_IN_USE, &jz4740_wdt.status);
+ return 0;
+}
+
+static const struct file_operations jz4740_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = jz4740_wdt_write,
+ .unlocked_ioctl = jz4740_wdt_ioctl,
+ .open = jz4740_wdt_open,
+ .release = jz4740_wdt_release,
+};
+
+static struct miscdevice jz4740_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &jz4740_wdt_fops,
+};
+
+static int __devinit jz4740_wdt_probe(struct platform_device *pdev)
+{
+ int ret = 0, size;
+ struct resource *res;
+ struct device *dev = &pdev->dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (res == NULL) {
+ dev_err(dev, "failed to get memory region resource\n");
+ return -ENXIO;
+ }
+
+ size = resource_size(res);
+ jz4740_wdt.mem = request_mem_region(res->start, size, pdev->name);
+ if (jz4740_wdt.mem == NULL) {
+ dev_err(dev, "failed to get memory region\n");
+ return -EBUSY;
+ }
+
+ jz4740_wdt.base = ioremap_nocache(res->start, size);
+ if (jz4740_wdt.base == NULL) {
+ dev_err(dev, "failed to map memory region\n");
+ ret = -EBUSY;
+ goto err_release_region;
+ }
+
+ jz4740_wdt.rtc_clk = clk_get(NULL, "rtc");
+ if (IS_ERR(jz4740_wdt.rtc_clk)) {
+ dev_err(dev, "cannot find RTC clock\n");
+ ret = PTR_ERR(jz4740_wdt.rtc_clk);
+ goto err_iounmap;
+ }
+
+ ret = misc_register(&jz4740_wdt_miscdev);
+ if (ret < 0) {
+ dev_err(dev, "cannot register misc device\n");
+ goto err_disable_clk;
+ }
+
+ return 0;
+
+err_disable_clk:
+ clk_put(jz4740_wdt.rtc_clk);
+err_iounmap:
+ iounmap(jz4740_wdt.base);
+err_release_region:
+ release_mem_region(jz4740_wdt.mem->start,
+ resource_size(jz4740_wdt.mem));
+ return ret;
+}
+
+
+static int __devexit jz4740_wdt_remove(struct platform_device *pdev)
+{
+ jz4740_wdt_disable();
+ misc_deregister(&jz4740_wdt_miscdev);
+ clk_put(jz4740_wdt.rtc_clk);
+
+ iounmap(jz4740_wdt.base);
+ jz4740_wdt.base = NULL;
+
+ release_mem_region(jz4740_wdt.mem->start,
+ resource_size(jz4740_wdt.mem));
+ jz4740_wdt.mem = NULL;
+
+ return 0;
+}
+
+
+static struct platform_driver jz4740_wdt_driver = {
+ .probe = jz4740_wdt_probe,
+ .remove = __devexit_p(jz4740_wdt_remove),
+ .driver = {
+ .name = "jz4740-wdt",
+ .owner = THIS_MODULE,
+ },
+};
+
+
+static int __init jz4740_wdt_init(void)
+{
+ return platform_driver_register(&jz4740_wdt_driver);
+}
+module_init(jz4740_wdt_init);
+
+static void __exit jz4740_wdt_exit(void)
+{
+ platform_driver_unregister(&jz4740_wdt_driver);
+}
+module_exit(jz4740_wdt_exit);
+
+MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
+MODULE_DESCRIPTION("jz4740 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);
+MODULE_ALIAS("platform:jz4740-wdt");
projects / platform / kernel / linux-exynos.git / commitdiff