[PATCH] OMAP: Add Watchdog driver support

Add Texas Instruments (TI) OMAP1/2 (http://www.ti.com/omap) based
processors, like OMAP1610/1710/242x.

[akpm@osdl.org: cleanups]
Cc: <gdavis@mvista.com>
Cc: "Komal Shah" <komal_shah802003@yahoo.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 391 insertions, 0 deletions

diff --git a/drivers/char/watchdog/omap_wdt.c b/drivers/char/watchdog/omap_wdt.c
new file mode 100644
index 000000000000..8f90b90a5021
--- /dev/null
+++ b/drivers/char/watchdog/omap_wdt.c
@@ -0,0 +1,391 @@
+/*
+ * linux/drivers/char/watchdog/omap_wdt.c
+ *
+ * Watchdog driver for the TI OMAP 16xx & 24xx 32KHz (non-secure) watchdog
+ *
+ * Author: MontaVista Software, Inc.
+ *       <gdavis@mvista.com> or <source@mvista.com>
+ *
+ * 2003 (c) MontaVista Software, Inc. This file is licensed under the
+ * terms of the GNU General Public License version 2. This program is
+ * licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ *
+ * History:
+ *
+ * 20030527: George G. Davis <gdavis@mvista.com>
+ *      Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
+ *      (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
+ *      Based on SoftDog driver by Alan Cox <alan@redhat.com>
+ *
+ * Copyright (c) 2004 Texas Instruments.
+ *      1. Modified to support OMAP1610 32-KHz watchdog timer
+ *      2. Ported to 2.6 kernel
+ *
+ * Copyright (c) 2005 David Brownell
+ *      Use the driver model and standard identifiers; handle bigger timeouts.
+ */
+
+#include <linux/module.h>
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/reboot.h>
+#include <linux/smp_lock.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/moduleparam.h>
+#include <linux/clk.h>
+
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/hardware.h>
+#include <asm/bitops.h>
+
+#include <asm/arch/prcm.h>
+
+#include "omap_wdt.h"
+
+static unsigned timer_margin;
+module_param(timer_margin, uint, 0);
+MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
+
+static int omap_wdt_users;
+static struct clk *armwdt_ck = NULL;
+static struct clk *mpu_wdt_ick = NULL;
+static struct clk *mpu_wdt_fck = NULL;
+
+static unsigned int wdt_trgr_pattern = 0x1234;
+
+static void omap_wdt_ping(void)
+{
+        /* wait for posted write to complete */
+        while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
+                cpu_relax();
+        wdt_trgr_pattern = ~wdt_trgr_pattern;
+        omap_writel(wdt_trgr_pattern, (OMAP_WATCHDOG_TGR));
+        /* wait for posted write to complete */
+        while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
+                cpu_relax();
+        /* reloaded WCRR from WLDR */
+}
+
+static void omap_wdt_enable(void)
+{
+        /* Sequence to enable the watchdog */
+        omap_writel(0xBBBB, OMAP_WATCHDOG_SPR);
+        while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10)
+                cpu_relax();
+        omap_writel(0x4444, OMAP_WATCHDOG_SPR);
+        while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10)
+                cpu_relax();
+}
+
+static void omap_wdt_disable(void)
+{
+        /* sequence required to disable watchdog */
+        omap_writel(0xAAAA, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
+        while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
+                cpu_relax();
+        omap_writel(0x5555, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
+        while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
+                cpu_relax();
+}
+
+static void omap_wdt_adjust_timeout(unsigned new_timeout)
+{
+        if (new_timeout < TIMER_MARGIN_MIN)
+                new_timeout = TIMER_MARGIN_DEFAULT;
+        if (new_timeout > TIMER_MARGIN_MAX)
+                new_timeout = TIMER_MARGIN_MAX;
+        timer_margin = new_timeout;
+}
+
+static void omap_wdt_set_timeout(void)
+{
+        u32 pre_margin = GET_WLDR_VAL(timer_margin);
+
+        /* just count up at 32 KHz */
+        while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
+                cpu_relax();
+        omap_writel(pre_margin, OMAP_WATCHDOG_LDR);
+        while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
+                cpu_relax();
+}
+
+/*
+ *      Allow only one task to hold it open
+ */
+
+static int omap_wdt_open(struct inode *inode, struct file *file)
+{
+        if (test_and_set_bit(1, (unsigned long *)&omap_wdt_users))
+                return -EBUSY;
+
+        if (cpu_is_omap16xx())
+                clk_enable(armwdt_ck);  /* Enable the clock */
+
+        if (cpu_is_omap24xx()) {
+                clk_enable(mpu_wdt_ick);    /* Enable the interface clock */
+                clk_enable(mpu_wdt_fck);    /* Enable the functional clock */
+        }
+
+        /* initialize prescaler */
+        while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
+                cpu_relax();
+        omap_writel((1 << 5) | (PTV << 2), OMAP_WATCHDOG_CNTRL);
+        while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
+                cpu_relax();
+
+        omap_wdt_set_timeout();
+        omap_wdt_enable();
+        return 0;
+}
+
+static int omap_wdt_release(struct inode *inode, struct file *file)
+{
+        /*
+         *      Shut off the timer unless NOWAYOUT is defined.
+         */
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+        omap_wdt_disable();
+
+        if (cpu_is_omap16xx()) {
+                clk_disable(armwdt_ck); /* Disable the clock */
+                clk_put(armwdt_ck);
+                armwdt_ck = NULL;
+        }
+
+        if (cpu_is_omap24xx()) {
+                clk_disable(mpu_wdt_ick);       /* Disable the clock */
+                clk_disable(mpu_wdt_fck);       /* Disable the clock */
+                clk_put(mpu_wdt_ick);
+                clk_put(mpu_wdt_fck);
+                mpu_wdt_ick = NULL;
+                mpu_wdt_fck = NULL;
+        }
+#else
+        printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
+#endif
+        omap_wdt_users = 0;
+        return 0;
+}
+
+static ssize_t
+omap_wdt_write(struct file *file, const char __user *data,
+                size_t len, loff_t *ppos)
+{
+        /* Refresh LOAD_TIME. */
+        if (len)
+                omap_wdt_ping();
+        return len;
+}
+
+static int
+omap_wdt_ioctl(struct inode *inode, struct file *file,
+        unsigned int cmd, unsigned long arg)
+{
+        int new_margin;
+        static struct watchdog_info ident = {
+                .identity = "OMAP Watchdog",
+                .options = WDIOF_SETTIMEOUT,
+                .firmware_version = 0,
+        };
+
+        switch (cmd) {
+        default:
+                return -ENOIOCTLCMD;
+        case WDIOC_GETSUPPORT:
+                return copy_to_user((struct watchdog_info __user *)arg, &ident,
+                                sizeof(ident));
+        case WDIOC_GETSTATUS:
+                return put_user(0, (int __user *)arg);
+        case WDIOC_GETBOOTSTATUS:
+                if (cpu_is_omap16xx())
+                        return put_user(omap_readw(ARM_SYSST),
+                                        (int __user *)arg);
+                if (cpu_is_omap24xx())
+                        return put_user(omap_prcm_get_reset_sources(),
+                                        (int __user *)arg);
+        case WDIOC_KEEPALIVE:
+                omap_wdt_ping();
+                return 0;
+        case WDIOC_SETTIMEOUT:
+                if (get_user(new_margin, (int __user *)arg))
+                        return -EFAULT;
+                omap_wdt_adjust_timeout(new_margin);
+
+                omap_wdt_disable();
+                omap_wdt_set_timeout();
+                omap_wdt_enable();
+
+                omap_wdt_ping();
+                /* Fall */
+        case WDIOC_GETTIMEOUT:
+                return put_user(timer_margin, (int __user *)arg);
+        }
+}
+
+static struct file_operations omap_wdt_fops = {
+        .owner = THIS_MODULE,
+        .write = omap_wdt_write,
+        .ioctl = omap_wdt_ioctl,
+        .open = omap_wdt_open,
+        .release = omap_wdt_release,
+};
+
+static struct miscdevice omap_wdt_miscdev = {
+        .minor = WATCHDOG_MINOR,
+        .name = "watchdog",
+        .fops = &omap_wdt_fops
+};
+
+static int __init omap_wdt_probe(struct platform_device *pdev)
+{
+        struct resource *res, *mem;
+        int ret;
+
+        /* reserve static register mappings */
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res)
+                return -ENOENT;
+
+        mem = request_mem_region(res->start, res->end - res->start + 1,
+                                 pdev->name);
+        if (mem == NULL)
+                return -EBUSY;
+
+        platform_set_drvdata(pdev, mem);
+
+        omap_wdt_users = 0;
+
+        if (cpu_is_omap16xx()) {
+                armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
+                if (IS_ERR(armwdt_ck)) {
+                        ret = PTR_ERR(armwdt_ck);
+                        armwdt_ck = NULL;
+                        goto fail;
+                }
+        }
+
+        if (cpu_is_omap24xx()) {
+                mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
+                if (IS_ERR(mpu_wdt_ick)) {
+                        ret = PTR_ERR(mpu_wdt_ick);
+                        mpu_wdt_ick = NULL;
+                        goto fail;
+                }
+                mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
+                if (IS_ERR(mpu_wdt_fck)) {
+                        ret = PTR_ERR(mpu_wdt_fck);
+                        mpu_wdt_fck = NULL;
+                        goto fail;
+                }
+        }
+
+        omap_wdt_disable();
+        omap_wdt_adjust_timeout(timer_margin);
+
+        omap_wdt_miscdev.dev = &pdev->dev;
+        ret = misc_register(&omap_wdt_miscdev);
+        if (ret)
+                goto fail;
+
+        pr_info("OMAP Watchdog Timer: initial timeout %d sec\n", timer_margin);
+
+        /* autogate OCP interface clock */
+        omap_writel(0x01, OMAP_WATCHDOG_SYS_CONFIG);
+        return 0;
+
+fail:
+        if (armwdt_ck)
+                clk_put(armwdt_ck);
+        if (mpu_wdt_ick)
+                clk_put(mpu_wdt_ick);
+        if (mpu_wdt_fck)
+                clk_put(mpu_wdt_fck);
+        release_resource(mem);
+        return ret;
+}
+
+static void omap_wdt_shutdown(struct platform_device *pdev)
+{
+        omap_wdt_disable();
+}
+
+static int omap_wdt_remove(struct platform_device *pdev)
+{
+        struct resource *mem = platform_get_drvdata(pdev);
+        misc_deregister(&omap_wdt_miscdev);
+        release_resource(mem);
+        if (armwdt_ck)
+                clk_put(armwdt_ck);
+        if (mpu_wdt_ick)
+                clk_put(mpu_wdt_ick);
+        if (mpu_wdt_fck)
+                clk_put(mpu_wdt_fck);
+        return 0;
+}
+
+#ifdef  CONFIG_PM
+
+/* REVISIT ... not clear this is the best way to handle system suspend; and
+ * it's very inappropriate for selective device suspend (e.g. suspending this
+ * through sysfs rather than by stopping the watchdog daemon).  Also, this
+ * may not play well enough with NOWAYOUT...
+ */
+
+static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
+{
+        if (omap_wdt_users)
+                omap_wdt_disable();
+        return 0;
+}
+
+static int omap_wdt_resume(struct platform_device *pdev)
+{
+        if (omap_wdt_users) {
+                omap_wdt_enable();
+                omap_wdt_ping();
+        }
+        return 0;
+}
+
+#else
+#define omap_wdt_suspend        NULL
+#define omap_wdt_resume         NULL
+#endif
+
+static struct platform_driver omap_wdt_driver = {
+        .probe          = omap_wdt_probe,
+        .remove         = omap_wdt_remove,
+        .shutdown       = omap_wdt_shutdown,
+        .suspend        = omap_wdt_suspend,
+        .resume         = omap_wdt_resume,
+        .driver         = {
+                .owner  = THIS_MODULE,
+                .name   = "omap_wdt",
+        },
+};
+
+static int __init omap_wdt_init(void)
+{
+        return platform_driver_register(&omap_wdt_driver);
+}
+
+static void __exit omap_wdt_exit(void)
+{
+        platform_driver_unregister(&omap_wdt_driver);
+}
+
+module_init(omap_wdt_init);
+module_exit(omap_wdt_exit);
+
+MODULE_AUTHOR("George G. Davis");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);