diff options
Diffstat (limited to 'drivers/watchdog/intel_scu_watchdog.c')
| -rw-r--r-- | drivers/watchdog/intel_scu_watchdog.c | 533 |
1 files changed, 533 insertions, 0 deletions
diff --git a/drivers/watchdog/intel_scu_watchdog.c b/drivers/watchdog/intel_scu_watchdog.c new file mode 100644 index 000000000..804e35940 --- /dev/null +++ b/drivers/watchdog/intel_scu_watchdog.c @@ -0,0 +1,533 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/compiler.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_heartbeat: 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 stream_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, + .compat_ioctl = compat_ptr_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(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; +} +late_initcall(intel_scu_watchdog_init); |