--- /dev/null
+/*
+ * Intel_SCU 0.2: An Intel SCU IOH Based Watchdog Device
+ * for Intel part #(s):
+ * - AF82MP20 PCH
+ *
+ * Copyright (C) 2009-2010 Intel Corporation. All rights reserved.
+ *
+ * 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.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/compiler.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <linux/sfi.h>
+#include <asm/irq.h>
+#include <linux/atomic.h>
+#include <asm/intel_scu_ipc.h>
+#include <asm/apb_timer.h>
+#include <asm/intel-mid.h>
+
+#include "intel_scu_watchdog.h"
+
+/* Bounds number of times we will retry loading time count */
+/* This retry is a work around for a silicon bug. */
+#define MAX_RETRY 16
+
+#define IPC_SET_WATCHDOG_TIMER 0xF8
+
+static int timer_margin = DEFAULT_SOFT_TO_HARD_MARGIN;
+module_param(timer_margin, int, 0);
+MODULE_PARM_DESC(timer_margin,
+ "Watchdog timer margin"
+ "Time between interrupt and resetting the system"
+ "The range is from 1 to 160"
+ "This is the time for all keep alives to arrive");
+
+static int timer_set = DEFAULT_TIME;
+module_param(timer_set, int, 0);
+MODULE_PARM_DESC(timer_set,
+ "Default Watchdog timer setting"
+ "Complete cycle time"
+ "The range is from 1 to 170"
+ "This is the time for all keep alives to arrive");
+
+/* After watchdog device is closed, check force_boot. If:
+ * force_boot == 0, then force boot on next watchdog interrupt after close,
+ * force_boot == 1, then force boot immediately when device is closed.
+ */
+static int force_boot;
+module_param(force_boot, int, 0);
+MODULE_PARM_DESC(force_boot,
+ "A value of 1 means that the driver will reboot"
+ "the system immediately if the /dev/watchdog device is closed"
+ "A value of 0 means that when /dev/watchdog device is closed"
+ "the watchdog timer will be refreshed for one more interval"
+ "of length: timer_set. At the end of this interval, the"
+ "watchdog timer will reset the system."
+ );
+
+/* there is only one device in the system now; this can be made into
+ * an array in the future if we have more than one device */
+
+static struct intel_scu_watchdog_dev watchdog_device;
+
+/* Forces restart, if force_reboot is set */
+static void watchdog_fire(void)
+{
+ if (force_boot) {
+ pr_crit("Initiating system reboot\n");
+ emergency_restart();
+ pr_crit("Reboot didn't ?????\n");
+ }
+
+ else {
+ pr_crit("Immediate Reboot Disabled\n");
+ pr_crit("System will reset when watchdog timer times out!\n");
+ }
+}
+
+static int check_timer_margin(int new_margin)
+{
+ if ((new_margin < MIN_TIME_CYCLE) ||
+ (new_margin > MAX_TIME - timer_set)) {
+ pr_debug("value of new_margin %d is out of the range %d to %d\n",
+ new_margin, MIN_TIME_CYCLE, MAX_TIME - timer_set);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+/*
+ * IPC operations
+ */
+static int watchdog_set_ipc(int soft_threshold, int threshold)
+{
+ u32 *ipc_wbuf;
+ u8 cbuf[16] = { '\0' };
+ int ipc_ret = 0;
+
+ ipc_wbuf = (u32 *)&cbuf;
+ ipc_wbuf[0] = soft_threshold;
+ ipc_wbuf[1] = threshold;
+
+ ipc_ret = intel_scu_ipc_command(
+ IPC_SET_WATCHDOG_TIMER,
+ 0,
+ ipc_wbuf,
+ 2,
+ NULL,
+ 0);
+
+ if (ipc_ret != 0)
+ pr_err("Error setting SCU watchdog timer: %x\n", ipc_ret);
+
+ return ipc_ret;
+};
+
+/*
+ * Intel_SCU operations
+ */
+
+/* timer interrupt handler */
+static irqreturn_t watchdog_timer_interrupt(int irq, void *dev_id)
+{
+ int int_status;
+ int_status = ioread32(watchdog_device.timer_interrupt_status_addr);
+
+ pr_debug("irq, int_status: %x\n", int_status);
+
+ if (int_status != 0)
+ return IRQ_NONE;
+
+ /* has the timer been started? If not, then this is spurious */
+ if (watchdog_device.timer_started == 0) {
+ pr_debug("spurious interrupt received\n");
+ return IRQ_HANDLED;
+ }
+
+ /* temporarily disable the timer */
+ iowrite32(0x00000002, watchdog_device.timer_control_addr);
+
+ /* set the timer to the threshold */
+ iowrite32(watchdog_device.threshold,
+ watchdog_device.timer_load_count_addr);
+
+ /* allow the timer to run */
+ iowrite32(0x00000003, watchdog_device.timer_control_addr);
+
+ return IRQ_HANDLED;
+}
+
+static int intel_scu_keepalive(void)
+{
+
+ /* read eoi register - clears interrupt */
+ ioread32(watchdog_device.timer_clear_interrupt_addr);
+
+ /* temporarily disable the timer */
+ iowrite32(0x00000002, watchdog_device.timer_control_addr);
+
+ /* set the timer to the soft_threshold */
+ iowrite32(watchdog_device.soft_threshold,
+ watchdog_device.timer_load_count_addr);
+
+ /* allow the timer to run */
+ iowrite32(0x00000003, watchdog_device.timer_control_addr);
+
+ return 0;
+}
+
+static int intel_scu_stop(void)
+{
+ iowrite32(0, watchdog_device.timer_control_addr);
+ return 0;
+}
+
+static int intel_scu_set_heartbeat(u32 t)
+{
+ int ipc_ret;
+ int retry_count;
+ u32 soft_value;
+ u32 hw_value;
+
+ watchdog_device.timer_set = t;
+ watchdog_device.threshold =
+ timer_margin * watchdog_device.timer_tbl_ptr->freq_hz;
+ watchdog_device.soft_threshold =
+ (watchdog_device.timer_set - timer_margin)
+ * watchdog_device.timer_tbl_ptr->freq_hz;
+
+ pr_debug("set_heartbeat: timer freq is %d\n",
+ watchdog_device.timer_tbl_ptr->freq_hz);
+ pr_debug("set_heartbeat: timer_set is %x (hex)\n",
+ watchdog_device.timer_set);
+ pr_debug("set_hearbeat: timer_margin is %x (hex)\n", timer_margin);
+ pr_debug("set_heartbeat: threshold is %x (hex)\n",
+ watchdog_device.threshold);
+ pr_debug("set_heartbeat: soft_threshold is %x (hex)\n",
+ watchdog_device.soft_threshold);
+
+ /* Adjust thresholds by FREQ_ADJUSTMENT factor, to make the */
+ /* watchdog timing come out right. */
+ watchdog_device.threshold =
+ watchdog_device.threshold / FREQ_ADJUSTMENT;
+ watchdog_device.soft_threshold =
+ watchdog_device.soft_threshold / FREQ_ADJUSTMENT;
+
+ /* temporarily disable the timer */
+ iowrite32(0x00000002, watchdog_device.timer_control_addr);
+
+ /* send the threshold and soft_threshold via IPC to the processor */
+ ipc_ret = watchdog_set_ipc(watchdog_device.soft_threshold,
+ watchdog_device.threshold);
+
+ if (ipc_ret != 0) {
+ /* Make sure the watchdog timer is stopped */
+ intel_scu_stop();
+ return ipc_ret;
+ }
+
+ /* Soft Threshold set loop. Early versions of silicon did */
+ /* not always set this count correctly. This loop checks */
+ /* the value and retries if it was not set correctly. */
+
+ retry_count = 0;
+ soft_value = watchdog_device.soft_threshold & 0xFFFF0000;
+ do {
+
+ /* Make sure timer is stopped */
+ intel_scu_stop();
+
+ if (MAX_RETRY < retry_count++) {
+ /* Unable to set timer value */
+ pr_err("Unable to set timer\n");
+ return -ENODEV;
+ }
+
+ /* set the timer to the soft threshold */
+ iowrite32(watchdog_device.soft_threshold,
+ watchdog_device.timer_load_count_addr);
+
+ /* read count value before starting timer */
+ ioread32(watchdog_device.timer_load_count_addr);
+
+ /* Start the timer */
+ iowrite32(0x00000003, watchdog_device.timer_control_addr);
+
+ /* read the value the time loaded into its count reg */
+ hw_value = ioread32(watchdog_device.timer_load_count_addr);
+ hw_value = hw_value & 0xFFFF0000;
+
+
+ } while (soft_value != hw_value);
+
+ watchdog_device.timer_started = 1;
+
+ return 0;
+}
+
+/*
+ * /dev/watchdog handling
+ */
+
+static int intel_scu_open(struct inode *inode, struct file *file)
+{
+
+ /* Set flag to indicate that watchdog device is open */
+ if (test_and_set_bit(0, &watchdog_device.driver_open))
+ return -EBUSY;
+
+ /* Check for reopen of driver. Reopens are not allowed */
+ if (watchdog_device.driver_closed)
+ return -EPERM;
+
+ return nonseekable_open(inode, file);
+}
+
+static int intel_scu_release(struct inode *inode, struct file *file)
+{
+ /*
+ * This watchdog should not be closed, after the timer
+ * is started with the WDIPC_SETTIMEOUT ioctl
+ * If force_boot is set watchdog_fire() will cause an
+ * immediate reset. If force_boot is not set, the watchdog
+ * timer is refreshed for one more interval. At the end
+ * of that interval, the watchdog timer will reset the system.
+ */
+
+ if (!test_and_clear_bit(0, &watchdog_device.driver_open)) {
+ pr_debug("intel_scu_release, without open\n");
+ return -ENOTTY;
+ }
+
+ if (!watchdog_device.timer_started) {
+ /* Just close, since timer has not been started */
+ pr_debug("closed, without starting timer\n");
+ return 0;
+ }
+
+ pr_crit("Unexpected close of /dev/watchdog!\n");
+
+ /* Since the timer was started, prevent future reopens */
+ watchdog_device.driver_closed = 1;
+
+ /* Refresh the timer for one more interval */
+ intel_scu_keepalive();
+
+ /* Reboot system (if force_boot is set) */
+ watchdog_fire();
+
+ /* We should only reach this point if force_boot is not set */
+ return 0;
+}
+
+static ssize_t intel_scu_write(struct file *file,
+ char const *data,
+ size_t len,
+ loff_t *ppos)
+{
+
+ if (watchdog_device.timer_started)
+ /* Watchdog already started, keep it alive */
+ intel_scu_keepalive();
+ else
+ /* Start watchdog with timer value set by init */
+ intel_scu_set_heartbeat(watchdog_device.timer_set);
+
+ return len;
+}
+
+static long intel_scu_ioctl(struct file *file,
+ unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ u32 __user *p = argp;
+ u32 new_margin;
+
+
+ static const struct watchdog_info ident = {
+ .options = WDIOF_SETTIMEOUT
+ | WDIOF_KEEPALIVEPING,
+ .firmware_version = 0, /* @todo Get from SCU via
+ ipc_get_scu_fw_version()? */
+ .identity = "Intel_SCU IOH Watchdog" /* len < 32 */
+ };
+
+ switch (cmd) {
+ 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:
+ intel_scu_keepalive();
+
+ return 0;
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_margin, p))
+ return -EFAULT;
+
+ if (check_timer_margin(new_margin))
+ return -EINVAL;
+
+ if (intel_scu_set_heartbeat(new_margin))
+ return -EINVAL;
+ return 0;
+ case WDIOC_GETTIMEOUT:
+ return put_user(watchdog_device.soft_threshold, p);
+
+ default:
+ return -ENOTTY;
+ }
+}
+
+/*
+ * Notifier for system down
+ */
+static int intel_scu_notify_sys(struct notifier_block *this,
+ unsigned long code,
+ void *another_unused)
+{
+ if (code == SYS_DOWN || code == SYS_HALT)
+ /* Turn off the watchdog timer. */
+ intel_scu_stop();
+ return NOTIFY_DONE;
+}
+
+/*
+ * Kernel Interfaces
+ */
+static const struct file_operations intel_scu_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = intel_scu_write,
+ .unlocked_ioctl = intel_scu_ioctl,
+ .open = intel_scu_open,
+ .release = intel_scu_release,
+};
+
+static int __init intel_scu_watchdog_init(void)
+{
+ int ret;
+ u32 __iomem *tmp_addr;
+
+ /*
+ * We don't really need to check this as the SFI timer get will fail
+ * but if we do so we can exit with a clearer reason and no noise.
+ *
+ * If it isn't an intel MID device then it doesn't have this watchdog
+ */
+ if (!intel_mid_identify_cpu())
+ return -ENODEV;
+
+ /* Check boot parameters to verify that their initial values */
+ /* are in range. */
+ /* Check value of timer_set boot parameter */
+ if ((timer_set < MIN_TIME_CYCLE) ||
+ (timer_set > MAX_TIME - MIN_TIME_CYCLE)) {
+ pr_err("value of timer_set %x (hex) is out of range from %x to %x (hex)\n",
+ timer_set, MIN_TIME_CYCLE, MAX_TIME - MIN_TIME_CYCLE);
+ return -EINVAL;
+ }
+
+ /* Check value of timer_margin boot parameter */
+ if (check_timer_margin(timer_margin))
+ return -EINVAL;
+
+ watchdog_device.timer_tbl_ptr = sfi_get_mtmr(sfi_mtimer_num-1);
+
+ if (watchdog_device.timer_tbl_ptr == NULL) {
+ pr_debug("timer is not available\n");
+ return -ENODEV;
+ }
+ /* make sure the timer exists */
+ if (watchdog_device.timer_tbl_ptr->phys_addr == 0) {
+ pr_debug("timer %d does not have valid physical memory\n",
+ sfi_mtimer_num);
+ return -ENODEV;
+ }
+
+ if (watchdog_device.timer_tbl_ptr->irq == 0) {
+ pr_debug("timer %d invalid irq\n", sfi_mtimer_num);
+ return -ENODEV;
+ }
+
+ tmp_addr = ioremap_nocache(watchdog_device.timer_tbl_ptr->phys_addr,
+ 20);
+
+ if (tmp_addr == NULL) {
+ pr_debug("timer unable to ioremap\n");
+ return -ENOMEM;
+ }
+
+ watchdog_device.timer_load_count_addr = tmp_addr++;
+ watchdog_device.timer_current_value_addr = tmp_addr++;
+ watchdog_device.timer_control_addr = tmp_addr++;
+ watchdog_device.timer_clear_interrupt_addr = tmp_addr++;
+ watchdog_device.timer_interrupt_status_addr = tmp_addr++;
+
+ /* Set the default time values in device structure */
+
+ watchdog_device.timer_set = timer_set;
+ watchdog_device.threshold =
+ timer_margin * watchdog_device.timer_tbl_ptr->freq_hz;
+ watchdog_device.soft_threshold =
+ (watchdog_device.timer_set - timer_margin)
+ * watchdog_device.timer_tbl_ptr->freq_hz;
+
+
+ watchdog_device.intel_scu_notifier.notifier_call =
+ intel_scu_notify_sys;
+
+ ret = register_reboot_notifier(&watchdog_device.intel_scu_notifier);
+ if (ret) {
+ pr_err("cannot register notifier %d)\n", ret);
+ goto register_reboot_error;
+ }
+
+ watchdog_device.miscdev.minor = WATCHDOG_MINOR;
+ watchdog_device.miscdev.name = "watchdog";
+ watchdog_device.miscdev.fops = &intel_scu_fops;
+
+ ret = misc_register(&watchdog_device.miscdev);
+ if (ret) {
+ pr_err("cannot register miscdev %d err =%d\n",
+ WATCHDOG_MINOR, ret);
+ goto misc_register_error;
+ }
+
+ ret = request_irq((unsigned int)watchdog_device.timer_tbl_ptr->irq,
+ watchdog_timer_interrupt,
+ IRQF_SHARED, "watchdog",
+ &watchdog_device.timer_load_count_addr);
+ if (ret) {
+ pr_err("error requesting irq %d\n", ret);
+ goto request_irq_error;
+ }
+ /* Make sure timer is disabled before returning */
+ intel_scu_stop();
+ return 0;
+
+/* error cleanup */
+
+request_irq_error:
+ misc_deregister(&watchdog_device.miscdev);
+misc_register_error:
+ unregister_reboot_notifier(&watchdog_device.intel_scu_notifier);
+register_reboot_error:
+ intel_scu_stop();
+ iounmap(watchdog_device.timer_load_count_addr);
+ return ret;
+}
+
+static void __exit intel_scu_watchdog_exit(void)
+{
+
+ misc_deregister(&watchdog_device.miscdev);
+ unregister_reboot_notifier(&watchdog_device.intel_scu_notifier);
+ /* disable the timer */
+ iowrite32(0x00000002, watchdog_device.timer_control_addr);
+ iounmap(watchdog_device.timer_load_count_addr);
+}
+
+late_initcall(intel_scu_watchdog_init);
+module_exit(intel_scu_watchdog_exit);
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("Intel SCU Watchdog Device Driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(WDT_VER);
Code Review / kvmfornfv.git / blobdiff