watchdog: Add watchdog driver for Intel Atom E6XX

Add driver for the watchdog timer built into the
Intel Atom E6XX (TunnelCreek) processor.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 347 insertions, 0 deletions

diff --git a/drivers/watchdog/ie6xx_wdt.c b/drivers/watchdog/ie6xx_wdt.c
new file mode 100644
index 000000000000..db21ce4a2c42
--- /dev/null
+++ b/drivers/watchdog/ie6xx_wdt.c
@@ -0,0 +1,347 @@
+/*
+ *      Intel Atom E6xx Watchdog driver
+ *
+ *      Copyright (C) 2011 Alexander Stein
+ *                <alexander.stein@systec-electronic.com>
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of version 2 of the GNU General
+ *      Public License as published by the Free Software Foundation.
+ *
+ *      This program is distributed in the hope that it will be
+ *      useful, but WITHOUT ANY WARRANTY; without even the implied
+ *      warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ *      PURPOSE.  See the GNU General Public License for more details.
+ *      You should have received a copy of the GNU General Public
+ *      License along with this program; if not, write to the Free
+ *      Software Foundation, Inc., 59 Temple Place - Suite 330,
+ *      Boston, MA  02111-1307, USA.
+ *      The full GNU General Public License is included in this
+ *      distribution in the file called COPYING.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <linux/miscdevice.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/spinlock.h>
+
+#define DRIVER_NAME "ie6xx_wdt"
+
+#define PV1     0x00
+#define PV2     0x04
+
+#define RR0     0x0c
+#define RR1     0x0d
+#define WDT_RELOAD      0x01
+#define WDT_TOUT        0x02
+
+#define WDTCR   0x10
+#define WDT_PRE_SEL     0x04
+#define WDT_RESET_SEL   0x08
+#define WDT_RESET_EN    0x10
+#define WDT_TOUT_EN     0x20
+
+#define DCR     0x14
+
+#define WDTLR   0x18
+#define WDT_LOCK        0x01
+#define WDT_ENABLE      0x02
+#define WDT_TOUT_CNF    0x03
+
+#define MIN_TIME        1
+#define MAX_TIME        (10 * 60) /* 10 minutes */
+#define DEFAULT_TIME    60
+
+static unsigned int timeout = DEFAULT_TIME;
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout,
+                "Default Watchdog timer setting ("
+                __MODULE_STRING(DEFAULT_TIME) "s)."
+                "The range is from 1 to 600");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+        "Watchdog cannot be stopped once started (default="
+                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static u8 resetmode = 0x10;
+module_param(resetmode, byte, 0);
+MODULE_PARM_DESC(resetmode,
+        "Resetmode bits: 0x08 warm reset (cold reset otherwise), "
+        "0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)");
+
+static struct {
+        unsigned short sch_wdtba;
+        struct spinlock unlock_sequence;
+#ifdef CONFIG_DEBUG_FS
+        struct dentry *debugfs;
+#endif
+} ie6xx_wdt_data;
+
+/*
+ * This is needed to write to preload and reload registers
+ * struct ie6xx_wdt_data.unlock_sequence must be used
+ * to prevent sequence interrupts
+ */
+static void ie6xx_wdt_unlock_registers(void)
+{
+        outb(0x80, ie6xx_wdt_data.sch_wdtba + RR0);
+        outb(0x86, ie6xx_wdt_data.sch_wdtba + RR0);
+}
+
+static int ie6xx_wdt_ping(struct watchdog_device *wdd)
+{
+        spin_lock(&ie6xx_wdt_data.unlock_sequence);
+        ie6xx_wdt_unlock_registers();
+        outb(WDT_RELOAD, ie6xx_wdt_data.sch_wdtba + RR1);
+        spin_unlock(&ie6xx_wdt_data.unlock_sequence);
+        return 0;
+}
+
+static int ie6xx_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
+{
+        u32 preload;
+        u64 clock;
+        u8 wdtcr;
+
+        /* Watchdog clock is PCI Clock (33MHz) */
+        clock = 33000000;
+        /* and the preload value is loaded into [34:15] of the down counter */
+        preload = (t * clock) >> 15;
+        /*
+         * Manual states preload must be one less.
+         * Does not wrap as t is at least 1
+         */
+        preload -= 1;
+
+        spin_lock(&ie6xx_wdt_data.unlock_sequence);
+
+        /* Set ResetMode & Enable prescaler for range 10ms to 10 min */
+        wdtcr = resetmode & 0x38;
+        outb(wdtcr, ie6xx_wdt_data.sch_wdtba + WDTCR);
+
+        ie6xx_wdt_unlock_registers();
+        outl(0, ie6xx_wdt_data.sch_wdtba + PV1);
+
+        ie6xx_wdt_unlock_registers();
+        outl(preload, ie6xx_wdt_data.sch_wdtba + PV2);
+
+        ie6xx_wdt_unlock_registers();
+        outb(WDT_RELOAD | WDT_TOUT, ie6xx_wdt_data.sch_wdtba + RR1);
+
+        spin_unlock(&ie6xx_wdt_data.unlock_sequence);
+
+        wdd->timeout = t;
+        return 0;
+}
+
+static int ie6xx_wdt_start(struct watchdog_device *wdd)
+{
+        ie6xx_wdt_set_timeout(wdd, wdd->timeout);
+
+        /* Enable the watchdog timer */
+        spin_lock(&ie6xx_wdt_data.unlock_sequence);
+        outb(WDT_ENABLE, ie6xx_wdt_data.sch_wdtba + WDTLR);
+        spin_unlock(&ie6xx_wdt_data.unlock_sequence);
+
+        return 0;
+}
+
+static int ie6xx_wdt_stop(struct watchdog_device *wdd)
+{
+        if (inb(ie6xx_wdt_data.sch_wdtba + WDTLR) & WDT_LOCK)
+                return -1;
+
+        /* Disable the watchdog timer */
+        spin_lock(&ie6xx_wdt_data.unlock_sequence);
+        outb(0, ie6xx_wdt_data.sch_wdtba + WDTLR);
+        spin_unlock(&ie6xx_wdt_data.unlock_sequence);
+
+        return 0;
+}
+
+static const struct watchdog_info ie6xx_wdt_info = {
+        .identity =     "Intel Atom E6xx Watchdog",
+        .options =      WDIOF_SETTIMEOUT |
+                        WDIOF_MAGICCLOSE |
+                        WDIOF_KEEPALIVEPING,
+};
+
+static const struct watchdog_ops ie6xx_wdt_ops = {
+        .owner =        THIS_MODULE,
+        .start =        ie6xx_wdt_start,
+        .stop =         ie6xx_wdt_stop,
+        .ping =         ie6xx_wdt_ping,
+        .set_timeout =  ie6xx_wdt_set_timeout,
+};
+
+static struct watchdog_device ie6xx_wdt_dev = {
+        .info =         &ie6xx_wdt_info,
+        .ops =          &ie6xx_wdt_ops,
+        .min_timeout =  MIN_TIME,
+        .max_timeout =  MAX_TIME,
+};
+
+#ifdef CONFIG_DEBUG_FS
+
+static int ie6xx_wdt_dbg_show(struct seq_file *s, void *unused)
+{
+        seq_printf(s, "PV1   = 0x%08x\n",
+                inl(ie6xx_wdt_data.sch_wdtba + PV1));
+        seq_printf(s, "PV2   = 0x%08x\n",
+                inl(ie6xx_wdt_data.sch_wdtba + PV2));
+        seq_printf(s, "RR    = 0x%08x\n",
+                inw(ie6xx_wdt_data.sch_wdtba + RR0));
+        seq_printf(s, "WDTCR = 0x%08x\n",
+                inw(ie6xx_wdt_data.sch_wdtba + WDTCR));
+        seq_printf(s, "DCR   = 0x%08x\n",
+                inl(ie6xx_wdt_data.sch_wdtba + DCR));
+        seq_printf(s, "WDTLR = 0x%08x\n",
+                inw(ie6xx_wdt_data.sch_wdtba + WDTLR));
+
+        seq_printf(s, "\n");
+        return 0;
+}
+
+static int ie6xx_wdt_dbg_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, ie6xx_wdt_dbg_show, NULL);
+}
+
+static const struct file_operations ie6xx_wdt_dbg_operations = {
+        .open           = ie6xx_wdt_dbg_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
+static void __devinit ie6xx_wdt_debugfs_init(void)
+{
+        /* /sys/kernel/debug/ie6xx_wdt */
+        ie6xx_wdt_data.debugfs = debugfs_create_file("ie6xx_wdt",
+                S_IFREG | S_IRUGO, NULL, NULL, &ie6xx_wdt_dbg_operations);
+}
+
+static void __devexit ie6xx_wdt_debugfs_exit(void)
+{
+        debugfs_remove(ie6xx_wdt_data.debugfs);
+}
+
+#else
+static void __devinit ie6xx_wdt_debugfs_init(void)
+{
+}
+
+static void __devexit ie6xx_wdt_debugfs_exit(void)
+{
+}
+#endif
+
+static int __devinit ie6xx_wdt_probe(struct platform_device *pdev)
+{
+        struct resource *res;
+        u8 wdtlr;
+        int ret;
+
+        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+        if (!res)
+                return -ENODEV;
+
+        if (!request_region(res->start, resource_size(res), pdev->name)) {
+                dev_err(&pdev->dev, "Watchdog region 0x%x already in use!\n",
+                        res->start);
+                return -EBUSY;
+        }
+
+        ie6xx_wdt_data.sch_wdtba = res->start;
+        dev_dbg(&pdev->dev, "WDT = 0x%X\n", ie6xx_wdt_data.sch_wdtba);
+
+        ie6xx_wdt_dev.timeout = timeout;
+        watchdog_set_nowayout(&ie6xx_wdt_dev, nowayout);
+
+        spin_lock_init(&ie6xx_wdt_data.unlock_sequence);
+
+        wdtlr = inb(ie6xx_wdt_data.sch_wdtba + WDTLR);
+        if (wdtlr & WDT_LOCK)
+                dev_warn(&pdev->dev,
+                        "Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr);
+
+        ie6xx_wdt_debugfs_init();
+
+        ret = watchdog_register_device(&ie6xx_wdt_dev);
+        if (ret) {
+                dev_err(&pdev->dev,
+                        "Watchdog timer: cannot register device (err =%d)\n",
+                                                                        ret);
+                goto misc_register_error;
+        }
+
+        return 0;
+
+misc_register_error:
+        ie6xx_wdt_debugfs_exit();
+        release_region(res->start, resource_size(res));
+        ie6xx_wdt_data.sch_wdtba = 0;
+        return ret;
+}
+
+static int __devexit ie6xx_wdt_remove(struct platform_device *pdev)
+{
+        struct resource *res;
+
+        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+        ie6xx_wdt_stop(NULL);
+        watchdog_unregister_device(&ie6xx_wdt_dev);
+        ie6xx_wdt_debugfs_exit();
+        release_region(res->start, resource_size(res));
+        ie6xx_wdt_data.sch_wdtba = 0;
+
+        return 0;
+}
+
+static struct platform_driver ie6xx_wdt_driver = {
+        .probe          = ie6xx_wdt_probe,
+        .remove         = __devexit_p(ie6xx_wdt_remove),
+        .driver         = {
+                .name   = DRIVER_NAME,
+                .owner  = THIS_MODULE,
+        },
+};
+
+static int __init ie6xx_wdt_init(void)
+{
+        /* Check boot parameters to verify that their initial values */
+        /* are in range. */
+        if ((timeout < MIN_TIME) ||
+            (timeout > MAX_TIME)) {
+                pr_err("Watchdog timer: value of timeout %d (dec) "
+                  "is out of range from %d to %d (dec)\n",
+                  timeout, MIN_TIME, MAX_TIME);
+                return -EINVAL;
+        }
+
+        return platform_driver_register(&ie6xx_wdt_driver);
+}
+
+static void __exit ie6xx_wdt_exit(void)
+{
+        platform_driver_unregister(&ie6xx_wdt_driver);
+}
+
+late_initcall(ie6xx_wdt_init);
+module_exit(ie6xx_wdt_exit);
+
+MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
+MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform:" DRIVER_NAME);