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[PATCH 1/2] TXx9 watchdog driver

To: linux-mips@linux-mips.org
Subject: [PATCH 1/2] TXx9 watchdog driver
From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Date: Mon, 12 Nov 2007 01:32:17 +0900 (JST)
Cc: ralf@linux-mips.org, wim@iguana.be
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
This is a driver for watchdog timer built into TXx9 MIPS SoCs.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
---
 drivers/watchdog/Kconfig   |    6 +
 drivers/watchdog/Makefile  |    1 +
 drivers/watchdog/txx9wdt.c |  276 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 283 insertions(+), 0 deletions(-)

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 2792bc1..7484ee6 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -616,6 +616,12 @@ config AR7_WDT
        help
          Hardware driver for the TI AR7 Watchdog Timer.
 
+config TXX9_WDT
+       tristate "Toshiba TXx9 Watchdog Timer"
+       depends on CPU_TX39XX || CPU_TX49XX
+       help
+         Hardware driver for the built-in watchdog timer on TXx9 MIPS SoCs.
+
 # PARISC Architecture
 
 # POWERPC Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 7d9e573..0458e62 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -91,6 +91,7 @@ obj-$(CONFIG_INDYDOG) += indydog.o
 obj-$(CONFIG_WDT_MTX1) += mtx-1_wdt.o
 obj-$(CONFIG_WDT_RM9K_GPI) += rm9k_wdt.o
 obj-$(CONFIG_AR7_WDT) += ar7_wdt.o
+obj-$(CONFIG_TXX9_WDT) += txx9wdt.o
 
 # PARISC Architecture
 
diff --git a/drivers/watchdog/txx9wdt.c b/drivers/watchdog/txx9wdt.c
new file mode 100644
index 0000000..f3af8f5
--- /dev/null
+++ b/drivers/watchdog/txx9wdt.c
@@ -0,0 +1,276 @@
+/*
+ * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
+ *
+ * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
+ *
+ * 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/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <asm/txx9tmr.h>
+
+#define TIMER_MARGIN   60              /* Default is 60 seconds */
+
+static int timeout = TIMER_MARGIN;     /* in seconds */
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout,
+       "Watchdog timeout in seconds. "
+       "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
+       "default=" __MODULE_STRING(TIMER_MARGIN) ")");
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout,
+       "Watchdog cannot be stopped once started "
+       "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+#define WD_TIMER_CCD   7       /* 1/256 */
+#define WD_TIMER_CLK   (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
+#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
+
+static unsigned long txx9wdt_alive;
+static int expect_close;
+static struct txx9_tmr_reg __iomem *txx9wdt_reg;
+static struct clk *txx9_imclk;
+
+static void txx9wdt_ping(void)
+{
+       __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
+}
+
+static void txx9wdt_start(void)
+{
+       __raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra);
+       __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
+       __raw_writel(0, &txx9wdt_reg->tisr);    /* clear pending interrupt */
+       __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
+                    &txx9wdt_reg->tcr);
+       __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
+}
+
+static void txx9wdt_stop(void)
+{
+       __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
+       __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
+                    &txx9wdt_reg->tcr);
+}
+
+static int txx9wdt_open(struct inode *inode, struct file *file)
+{
+       if (test_and_set_bit(0, &txx9wdt_alive))
+               return -EBUSY;
+
+       if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) {
+               clear_bit(0, &txx9wdt_alive);
+               return -EBUSY;
+       }
+
+       if (nowayout)
+               __module_get(THIS_MODULE);
+
+       txx9wdt_start();
+       return nonseekable_open(inode, file);
+}
+
+static int txx9wdt_release(struct inode *inode, struct file *file)
+{
+       if (expect_close)
+               txx9wdt_stop();
+       else {
+               printk(KERN_CRIT "txx9wdt: "
+                      "Unexpected close, not stopping watchdog!\n");
+               txx9wdt_ping();
+       }
+       clear_bit(0, &txx9wdt_alive);
+       expect_close = 0;
+       return 0;
+}
+
+static ssize_t txx9wdt_write(struct file *file, const char __user *data,
+                            size_t len, loff_t *ppos)
+{
+       if (len) {
+               if (!nowayout) {
+                       size_t i;
+
+                       expect_close = 0;
+                       for (i = 0; i != len; i++) {
+                               char c;
+                               if (get_user(c, data + i))
+                                       return -EFAULT;
+                               if (c == 'V')
+                                       expect_close = 1;
+                       }
+               }
+               txx9wdt_ping();
+       }
+       return len;
+}
+
+static int txx9wdt_ioctl(struct inode *inode, struct file *file,
+       unsigned int cmd, unsigned long arg)
+{
+       void __user *argp = (void __user *)arg;
+       int __user *p = argp;
+       int new_timeout;
+       static struct watchdog_info ident = {
+               .options =              WDIOF_SETTIMEOUT |
+                                       WDIOF_KEEPALIVEPING |
+                                       WDIOF_MAGICCLOSE,
+               .firmware_version =     0,
+               .identity =             "Hardware Watchdog for TXx9",
+       };
+
+       switch (cmd) {
+       default:
+               return -ENOTTY;
+       case WDIOC_GETSUPPORT:
+               return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+       case WDIOC_GETSTATUS:
+       case WDIOC_GETBOOTSTATUS:
+               return put_user(0, p);
+       case WDIOC_KEEPALIVE:
+               txx9wdt_ping();
+               return 0;
+       case WDIOC_SETTIMEOUT:
+               if (get_user(new_timeout, p))
+                       return -EFAULT;
+               if (new_timeout < 1 || new_timeout > WD_MAX_TIMEOUT)
+                       return -EINVAL;
+               timeout = new_timeout;
+               txx9wdt_stop();
+               txx9wdt_start();
+               /* Fall */
+       case WDIOC_GETTIMEOUT:
+               return put_user(timeout, p);
+       }
+}
+
+static int txx9wdt_notify_sys(struct notifier_block *this, unsigned long code,
+       void *unused)
+{
+       if (code == SYS_DOWN || code == SYS_HALT)
+               txx9wdt_stop();
+       return NOTIFY_DONE;
+}
+
+static const struct file_operations txx9wdt_fops = {
+       .owner =        THIS_MODULE,
+       .llseek =       no_llseek,
+       .write =        txx9wdt_write,
+       .ioctl =        txx9wdt_ioctl,
+       .open =         txx9wdt_open,
+       .release =      txx9wdt_release,
+};
+
+static struct miscdevice txx9wdt_miscdev = {
+       .minor =        WATCHDOG_MINOR,
+       .name =         "watchdog",
+       .fops =         &txx9wdt_fops,
+};
+
+static struct notifier_block txx9wdt_notifier = {
+       .notifier_call = txx9wdt_notify_sys
+};
+
+static int __init txx9wdt_probe(struct platform_device *dev)
+{
+       struct resource *res;
+       int ret;
+
+       txx9_imclk = clk_get(NULL, "imbus_clk");
+       if (IS_ERR(txx9_imclk)) {
+               ret = PTR_ERR(txx9_imclk);
+               txx9_imclk = NULL;
+               goto exit;
+       }
+       ret = clk_enable(txx9_imclk);
+       if (ret) {
+               clk_put(txx9_imclk);
+               txx9_imclk = NULL;
+               goto exit;
+       }
+
+       res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+       if (!res)
+               goto exit_busy;
+       if (!devm_request_mem_region(&dev->dev,
+                                    res->start, res->end - res->start + 1,
+                                    "txx9wdt"))
+               goto exit_busy;
+       txx9wdt_reg = devm_ioremap(&dev->dev,
+                                  res->start, res->end - res->start + 1);
+       if (!txx9wdt_reg)
+               goto exit_busy;
+
+       ret = misc_register(&txx9wdt_miscdev);
+       if (ret)
+               goto exit;
+
+       ret = register_reboot_notifier(&txx9wdt_notifier);
+       if (ret) {
+               misc_deregister(&txx9wdt_miscdev);
+               goto exit;
+       }
+
+       printk(KERN_INFO "Hardware Watchdog Timer for TXx9: "
+              "timeout=%d sec (max %ld) (nowayout= %d)\n",
+              timeout, WD_MAX_TIMEOUT, nowayout);
+
+       return 0;
+exit_busy:
+       ret = -EBUSY;
+exit:
+       if (txx9_imclk) {
+               clk_disable(txx9_imclk);
+               clk_put(txx9_imclk);
+       }
+       return ret;
+}
+
+static int __exit txx9wdt_remove(struct platform_device *dev)
+{
+       misc_deregister(&txx9wdt_miscdev);
+       unregister_reboot_notifier(&txx9wdt_notifier);
+       clk_disable(txx9_imclk);
+       clk_put(txx9_imclk);
+       return 0;
+}
+
+static struct platform_driver txx9wdt_driver = {
+       .remove = __exit_p(txx9wdt_remove),
+       .driver = {
+               .name = "txx9wdt",
+               .owner = THIS_MODULE,
+       },
+};
+
+static int __init watchdog_init(void)
+{
+       return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe);
+}
+
+static void __exit watchdog_exit(void)
+{
+       platform_driver_unregister(&txx9wdt_driver);
+}
+
+module_init(watchdog_init);
+module_exit(watchdog_exit);
+
+MODULE_DESCRIPTION("TXx9 Watchdog Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

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