[PATCH 05/10] MIPS: lantiq: add watchdog support

[John Crispin <blogic@openwrt.org>]

This patch adds the driver for the watchdog found inside the Lantiq SoC family.

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Ralph Hempel <ralph.hempel@lantiq.com>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: linux-mips@linux-mips.org
Cc: linux-watchdog@vger.kernel.org
---
 drivers/watchdog/Kconfig      |    6 +
 drivers/watchdog/Makefile     |    1 +
 drivers/watchdog/lantiq_wdt.c |  208 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 215 insertions(+), 0 deletions(-)
 create mode 100644 drivers/watchdog/lantiq_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index a5ad77e..3e0733e 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -930,6 +930,12 @@ config BCM63XX_WDT
          To compile this driver as a loadable module, choose M here.
          The module will be called bcm63xx_wdt.
 
+config LANTIQ_WDT
+       tristate "Lantiq SoC watchdog"
+       depends on LANTIQ
+       help
+         Hardware driver for the Lantiq SoC Watchdog Timer.
+
 # PARISC Architecture
 
 # POWERPC Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 4b0ef38..d845e47 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -119,6 +119,7 @@ obj-$(CONFIG_AR7_WDT) += ar7_wdt.o
 obj-$(CONFIG_TXX9_WDT) += txx9wdt.o
 obj-$(CONFIG_OCTEON_WDT) += octeon-wdt.o
 octeon-wdt-y := octeon-wdt-main.o octeon-wdt-nmi.o
+obj-$(CONFIG_LANTIQ_WDT) += lantiq_wdt.o
 
 # PARISC Architecture
 
diff --git a/drivers/watchdog/lantiq_wdt.c b/drivers/watchdog/lantiq_wdt.c
new file mode 100644
index 0000000..543bcf1
--- /dev/null
+++ b/drivers/watchdog/lantiq_wdt.c
@@ -0,0 +1,208 @@
+/*
+ *  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.
+ *
+ *  Copyright (C) 2010 John Crispin <blogic@openwrt.org>
+ *  Based on EP93xx wdt driver
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/uaccess.h>
+#include <linux/clk.h>
+
+#include <lantiq.h>
+
+#define LTQ_WDT_PW1                    0x00BE0000
+#define LTQ_WDT_PW2                    0x00DC0000
+
+#define LTQ_BIU_WDT_CR         0x3F0
+#define LTQ_BIU_WDT_SR         0x3F8
+
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+static int wdt_ok_to_close;
+#endif
+
+static int wdt_timeout = 30;
+static __iomem void *wdt_membase;
+static unsigned long io_region_clk;
+
+static int
+ltq_wdt_enable(unsigned int timeout)
+{
+       ltq_w32(LTQ_WDT_PW1, wdt_membase + LTQ_BIU_WDT_CR);
+       ltq_w32(LTQ_WDT_PW2 |
+               (0x3 << 26) | /* PWL */
+               (0x3 << 24) | /* CLKDIV */
+               (0x1 << 31) | /* enable */
+               ((timeout * (io_region_clk / 0x40000)) + 0x1000), /* reload */
+                       wdt_membase + LTQ_BIU_WDT_CR);
+       return 0;
+}
+
+static void
+ltq_wdt_disable(void)
+{
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+       wdt_ok_to_close = 0;
+#endif
+       ltq_w32(LTQ_WDT_PW1, wdt_membase + LTQ_BIU_WDT_CR);
+       ltq_w32(LTQ_WDT_PW2, wdt_membase + LTQ_BIU_WDT_CR);
+}
+
+static ssize_t
+ltq_wdt_write(struct file *file, const char __user *data,
+               size_t len, loff_t *ppos)
+{
+       size_t i;
+       if (!len)
+               return 0;
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+       for (i = 0; i != len; i++) {
+               char c;
+               if (get_user(c, data + i))
+                       return -EFAULT;
+               if (c == 'V')
+                       wdt_ok_to_close = 1;
+       }
+#endif
+       ltq_wdt_enable(wdt_timeout);
+       return len;
+}
+
+static struct watchdog_info ident = {
+       .options = WDIOF_MAGICCLOSE,
+       .identity = "ltq_wdt",
+};
+
+static long
+ltq_wdt_ioctl(struct file *file,
+               unsigned int cmd, unsigned long arg)
+{
+       int ret = -ENOTTY;
+       switch (cmd) {
+       case WDIOC_GETSUPPORT:
+               ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
+                               sizeof(ident)) ? -EFAULT : 0;
+               break;
+
+       case WDIOC_GETTIMEOUT:
+               ret = put_user(wdt_timeout, (int __user *)arg);
+               break;
+
+       case WDIOC_SETTIMEOUT:
+               ret = get_user(wdt_timeout, (int __user *)arg);
+               break;
+
+       case WDIOC_KEEPALIVE:
+               ltq_wdt_enable(wdt_timeout);
+               ret = 0;
+               break;
+       }
+       return ret;
+}
+
+static int
+ltq_wdt_open(struct inode *inode, struct file *file)
+{
+       ltq_wdt_enable(wdt_timeout);
+       return nonseekable_open(inode, file);
+}
+
+static int
+ltq_wdt_release(struct inode *inode, struct file *file)
+{
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+       if (wdt_ok_to_close)
+               ltq_wdt_disable();
+       else
+#endif
+               printk(KERN_ERR "ltq_wdt: watchdog closed without warning,"
+                       " rebooting system\n");
+       return 0;
+}
+
+static const struct file_operations ltq_wdt_fops = {
+       .owner                  = THIS_MODULE,
+       .write                  = ltq_wdt_write,
+       .unlocked_ioctl = ltq_wdt_ioctl,
+       .open                   = ltq_wdt_open,
+       .release                = ltq_wdt_release,
+};
+
+static struct miscdevice ltq_wdt_miscdev = {
+       .minor          = WATCHDOG_MINOR,
+       .name           = "watchdog",
+       .fops           = &ltq_wdt_fops,
+};
+
+static int
+ltq_wdt_probe(struct platform_device *pdev)
+{
+       struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       struct clk *clk;
+       int ret = 0;
+       if (!res)
+               return -ENOENT;
+       res = request_mem_region(res->start, resource_size(res),
+               dev_name(&pdev->dev));
+       if (!res)
+               return -EBUSY;
+       wdt_membase = ioremap_nocache(res->start, resource_size(res));
+       if (!wdt_membase) {
+               ret = -ENOMEM;
+               goto err_release_mem_region;
+       }
+       clk = clk_get(&pdev->dev, "io");
+       io_region_clk = clk_get_rate(clk);;
+       ret = misc_register(&ltq_wdt_miscdev);
+       if (!ret)
+               return 0;
+
+       iounmap(wdt_membase);
+err_release_mem_region:
+       release_mem_region(res->start, resource_size(res));
+       return ret;
+}
+
+static int
+ltq_wdt_remove(struct platform_device *dev)
+{
+       ltq_wdt_disable();
+       misc_deregister(&ltq_wdt_miscdev);
+       return 0;
+}
+
+static struct platform_driver ltq_wdt_driver = {
+       .probe = ltq_wdt_probe,
+       .remove = ltq_wdt_remove,
+       .driver = {
+               .name = "ltq_wdt",
+               .owner = THIS_MODULE,
+       },
+};
+
+static int __init
+init_ltq_wdt(void)
+{
+       return platform_driver_register(&ltq_wdt_driver);
+}
+
+static void __exit
+exit_ltq_wdt(void)
+{
+       platform_driver_unregister(&ltq_wdt_driver);
+}
+
+module_init(init_ltq_wdt);
+module_exit(exit_ltq_wdt);
+
+MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
+MODULE_DESCRIPTION("Lantiq Watchdog");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
-- 
1.7.2.3