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