+/*
+ * Watchdog driver for Cortina Systems Gemini SoC
+ *
+ * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/miscdevice.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/slab.h>
+
+#define GEMINI_WDCOUNTER 0x0
+#define GEMINI_WDLOAD 0x4
+#define GEMINI_WDRESTART 0x8
+
+#define WDRESTART_MAGIC 0x5AB9
+
+#define GEMINI_WDCR 0xC
+
+#define WDCR_CLOCK_5MHZ (1 << 4)
+#define WDCR_SYS_RST (1 << 1)
+#define WDCR_ENABLE (1 << 0)
+
+#define WDT_CLOCK 5000000 /* 5 MHz */
+#define WDT_DEFAULT_TIMEOUT 13
+#define WDT_MAX_TIMEOUT (0xFFFFFFFF / WDT_CLOCK)
+
+/* status bits */
+#define WDT_ACTIVE 0
+#define WDT_OK_TO_CLOSE 1
+
+static unsigned int timeout = WDT_DEFAULT_TIMEOUT;
+static int nowayout = WATCHDOG_NOWAYOUT;
+
+static DEFINE_SPINLOCK(gemini_wdt_lock);
+
+static struct platform_device *gemini_wdt_dev;
+
+struct gemini_wdt_struct {
+ struct resource *res;
+ struct device *dev;
+ void __iomem *base;
+ unsigned long status;
+};
+
+static struct watchdog_info gemini_wdt_info = {
+ .identity = "Gemini watchdog",
+ .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
+ WDIOF_SETTIMEOUT,
+};
+
+/* Disable the watchdog. */
+static void gemini_wdt_stop(struct gemini_wdt_struct *gemini_wdt)
+{
+ spin_lock(&gemini_wdt_lock);
+
+ __raw_writel(0, gemini_wdt->base + GEMINI_WDCR);
+
+ clear_bit(WDT_ACTIVE, &gemini_wdt->status);
+
+ spin_unlock(&gemini_wdt_lock);
+}
+
+/* Service the watchdog */
+static void gemini_wdt_service(struct gemini_wdt_struct *gemini_wdt)
+{
+ __raw_writel(WDRESTART_MAGIC, gemini_wdt->base + GEMINI_WDRESTART);
+}
+
+/* Enable and reset the watchdog. */
+static void gemini_wdt_start(struct gemini_wdt_struct *gemini_wdt)
+{
+ spin_lock(&gemini_wdt_lock);
+
+ __raw_writel(timeout * WDT_CLOCK, gemini_wdt->base + GEMINI_WDLOAD);
+
+ gemini_wdt_service(gemini_wdt);
+
+ /* set clock before enabling */
+ __raw_writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST,
+ gemini_wdt->base + GEMINI_WDCR);
+
+ __raw_writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE,
+ gemini_wdt->base + GEMINI_WDCR);
+
+ set_bit(WDT_ACTIVE, &gemini_wdt->status);
+
+ spin_unlock(&gemini_wdt_lock);
+}
+
+/* Watchdog device is opened, and watchdog starts running. */
+static int gemini_wdt_open(struct inode *inode, struct file *file)
+{
+ struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(gemini_wdt_dev);
+
+ if (test_bit(WDT_ACTIVE, &gemini_wdt->status))
+ return -EBUSY;
+
+ file->private_data = gemini_wdt;
+
+ gemini_wdt_start(gemini_wdt);
+
+ return nonseekable_open(inode, file);
+}
+
+/* Close the watchdog device. */
+static int gemini_wdt_close(struct inode *inode, struct file *file)
+{
+ struct gemini_wdt_struct *gemini_wdt = file->private_data;
+
+ /* Disable the watchdog if possible */
+ if (test_bit(WDT_OK_TO_CLOSE, &gemini_wdt->status))
+ gemini_wdt_stop(gemini_wdt);
+ else
+ dev_warn(gemini_wdt->dev, "Device closed unexpectedly - timer will not stop\n");
+
+ return 0;
+}
+
+/* Handle commands from user-space. */
+static long gemini_wdt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct gemini_wdt_struct *gemini_wdt = file->private_data;
+
+ int value;
+
+ switch (cmd) {
+ case WDIOC_KEEPALIVE:
+ gemini_wdt_service(gemini_wdt);
+ return 0;
+
+ case WDIOC_GETSUPPORT:
+ return copy_to_user((struct watchdog_info *)arg, &gemini_wdt_info,
+ sizeof(gemini_wdt_info)) ? -EFAULT : 0;
+
+ case WDIOC_SETTIMEOUT:
+ if (get_user(value, (int *)arg))
+ return -EFAULT;
+
+ if ((value < 1) || (value > WDT_MAX_TIMEOUT))
+ return -EINVAL;
+
+ timeout = value;
+
+ /* restart wdt to use new timeout */
+ gemini_wdt_stop(gemini_wdt);
+ gemini_wdt_start(gemini_wdt);
+
+ /* Fall through */
+ case WDIOC_GETTIMEOUT:
+ return put_user(timeout, (int *)arg);
+
+ case WDIOC_GETTIMELEFT:
+ value = __raw_readl(gemini_wdt->base + GEMINI_WDCOUNTER);
+ return put_user(value / WDT_CLOCK, (int *)arg);
+
+ default:
+ return -ENOTTY;
+ }
+}
+
+/* Refresh the watchdog whenever device is written to. */
+static ssize_t gemini_wdt_write(struct file *file, const char *data,
+ size_t len, loff_t *ppos)
+{
+ struct gemini_wdt_struct *gemini_wdt = file->private_data;
+
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ clear_bit(WDT_OK_TO_CLOSE, &gemini_wdt->status);
+ for (i = 0; i != len; i++) {
+ char c;
+
+ if (get_user(c, data + i))
+ return -EFAULT;
+ if (c == 'V')
+ set_bit(WDT_OK_TO_CLOSE,
+ &gemini_wdt->status);
+ }
+ }
+ gemini_wdt_service(gemini_wdt);
+ }
+
+ return len;
+}
+
+static const struct file_operations gemini_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .unlocked_ioctl = gemini_wdt_ioctl,
+ .open = gemini_wdt_open,
+ .release = gemini_wdt_close,
+ .write = gemini_wdt_write,
+};
+
+static struct miscdevice gemini_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &gemini_wdt_fops,
+};
+
+static void gemini_wdt_shutdown(struct platform_device *pdev)
+{
+ struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
+
+ gemini_wdt_stop(gemini_wdt);
+}
+
+static int gemini_wdt_probe(struct platform_device *pdev)
+{
+ int ret;
+ int res_size;
+ struct resource *res;
+ void __iomem *base;
+ struct gemini_wdt_struct *gemini_wdt;
+ unsigned int reg;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "can't get device resources\n");
+ return -ENODEV;
+ }
+
+ res_size = resource_size(res);
+ if (!request_mem_region(res->start, res_size, res->name)) {
+ dev_err(&pdev->dev, "can't allocate %d bytes at %d address\n",
+ res_size, res->start);
+ return -ENOMEM;
+ }
+
+ base = ioremap(res->start, res_size);
+ if (!base) {
+ dev_err(&pdev->dev, "ioremap failed\n");
+ ret = -EIO;
+ goto fail0;
+ }
+
+ gemini_wdt = kzalloc(sizeof(struct gemini_wdt_struct), GFP_KERNEL);
+ if (!gemini_wdt) {
+ dev_err(&pdev->dev, "can't allocate interface\n");
+ ret = -ENOMEM;
+ goto fail1;
+ }
+
+ /* Setup gemini_wdt driver structure */
+ gemini_wdt->base = base;
+ gemini_wdt->res = res;
+
+ /* Set up platform driver data */
+ platform_set_drvdata(pdev, gemini_wdt);
+ gemini_wdt_dev = pdev;
+
+ if (gemini_wdt_miscdev.parent) {
+ ret = -EBUSY;
+ goto fail2;
+ }
+
+ gemini_wdt_miscdev.parent = &pdev->dev;
+
+ reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR);
+ if (reg & WDCR_ENABLE) {
+ /* Watchdog was enabled by the bootloader, disable it. */
+ reg &= ~(WDCR_ENABLE);
+ __raw_writel(reg, gemini_wdt->base + GEMINI_WDCR);
+ }
+
+ ret = misc_register(&gemini_wdt_miscdev);
+ if (ret)
+ goto fail2;
+
+ return 0;
+
+fail2:
+ platform_set_drvdata(pdev, NULL);
+ kfree(gemini_wdt);
+fail1:
+ iounmap(base);
+fail0:
+ release_mem_region(res->start, res_size);
+
+ return ret;
+}
+
+static int gemini_wdt_remove(struct platform_device *pdev)
+{
+ struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
+
+ platform_set_drvdata(pdev, NULL);
+ misc_deregister(&gemini_wdt_miscdev);
+ gemini_wdt_dev = NULL;
+ iounmap(gemini_wdt->base);
+ release_mem_region(gemini_wdt->res->start, resource_size(gemini_wdt->res));
+
+ kfree(gemini_wdt);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int gemini_wdt_suspend(struct platform_device *pdev, pm_message_t message)
+{
+ struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
+ unsigned int reg;
+
+ reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR);
+ reg &= ~(WDCR_WDENABLE);
+ __raw_writel(reg, gemini_wdt->base + GEMINI_WDCR);
+
+ return 0;
+}
+
+static int gemini_wdt_resume(struct platform_device *pdev)
+{
+ struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev);
+ unsigned int reg;
+
+ if (gemini_wdt->status) {
+ reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR);
+ reg |= WDCR_WDENABLE;
+ __raw_writel(reg, gemini_wdt->base + GEMINI_WDCR);
+ }
+
+ return 0;
+}
+#else
+#define gemini_wdt_suspend NULL
+#define gemini_wdt_resume NULL
+#endif
+
+static struct platform_driver gemini_wdt_driver = {
+ .probe = gemini_wdt_probe,
+ .remove = gemini_wdt_remove,
+ .shutdown = gemini_wdt_shutdown,
+ .suspend = gemini_wdt_suspend,
+ .resume = gemini_wdt_resume,
+ .driver = {
+ .name = "gemini-wdt",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init gemini_wdt_init(void)
+{
+ return platform_driver_probe(&gemini_wdt_driver, gemini_wdt_probe);
+}
+
+static void __exit gemini_wdt_exit(void)
+{
+ platform_driver_unregister(&gemini_wdt_driver);
+}
+
+module_init(gemini_wdt_init);
+module_exit(gemini_wdt_exit);
+
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
+
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
+
+MODULE_AUTHOR("Paulius Zaleckas");
+MODULE_DESCRIPTION("Watchdog driver for Gemini");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform:gemini-wdt");
projects / openwrt / staging / yousong.git / blobdiff