| // SPDX-License-Identifier: GPL-2.0-only |
| /* cpwd.c - driver implementation for hardware watchdog |
| * timers found on Sun Microsystems CP1400 and CP1500 boards. |
| * |
| * This device supports both the generic Linux watchdog |
| * interface and Solaris-compatible ioctls as best it is |
| * able. |
| * |
| * NOTE: CP1400 systems appear to have a defective intr_mask |
| * register on the PLD, preventing the disabling of |
| * timer interrupts. We use a timer to periodically |
| * reset 'stopped' watchdogs on affected platforms. |
| * |
| * Copyright (c) 2000 Eric Brower (ebrower@usa.net) |
| * Copyright (C) 2008 David S. Miller <davem@davemloft.net> |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/fs.h> |
| #include <linux/errno.h> |
| #include <linux/major.h> |
| #include <linux/miscdevice.h> |
| #include <linux/interrupt.h> |
| #include <linux/ioport.h> |
| #include <linux/timer.h> |
| #include <linux/slab.h> |
| #include <linux/mutex.h> |
| #include <linux/io.h> |
| #include <linux/of.h> |
| #include <linux/of_device.h> |
| #include <linux/uaccess.h> |
| |
| #include <asm/irq.h> |
| #include <asm/watchdog.h> |
| |
| #define DRIVER_NAME "cpwd" |
| |
| #define WD_OBPNAME "watchdog" |
| #define WD_BADMODEL "SUNW,501-5336" |
| #define WD_BTIMEOUT (jiffies + (HZ * 1000)) |
| #define WD_BLIMIT 0xFFFF |
| |
| #define WD0_MINOR 212 |
| #define WD1_MINOR 213 |
| #define WD2_MINOR 214 |
| |
| /* Internal driver definitions. */ |
| #define WD0_ID 0 |
| #define WD1_ID 1 |
| #define WD2_ID 2 |
| #define WD_NUMDEVS 3 |
| |
| #define WD_INTR_OFF 0 |
| #define WD_INTR_ON 1 |
| |
| #define WD_STAT_INIT 0x01 /* Watchdog timer is initialized */ |
| #define WD_STAT_BSTOP 0x02 /* Watchdog timer is brokenstopped */ |
| #define WD_STAT_SVCD 0x04 /* Watchdog interrupt occurred */ |
| |
| /* Register value definitions |
| */ |
| #define WD0_INTR_MASK 0x01 /* Watchdog device interrupt masks */ |
| #define WD1_INTR_MASK 0x02 |
| #define WD2_INTR_MASK 0x04 |
| |
| #define WD_S_RUNNING 0x01 /* Watchdog device status running */ |
| #define WD_S_EXPIRED 0x02 /* Watchdog device status expired */ |
| |
| struct cpwd { |
| void __iomem *regs; |
| spinlock_t lock; |
| |
| unsigned int irq; |
| |
| unsigned long timeout; |
| bool enabled; |
| bool reboot; |
| bool broken; |
| bool initialized; |
| |
| struct { |
| struct miscdevice misc; |
| void __iomem *regs; |
| u8 intr_mask; |
| u8 runstatus; |
| u16 timeout; |
| } devs[WD_NUMDEVS]; |
| }; |
| |
| static DEFINE_MUTEX(cpwd_mutex); |
| static struct cpwd *cpwd_device; |
| |
| /* Sun uses Altera PLD EPF8820ATC144-4 |
| * providing three hardware watchdogs: |
| * |
| * 1) RIC - sends an interrupt when triggered |
| * 2) XIR - asserts XIR_B_RESET when triggered, resets CPU |
| * 3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board |
| * |
| *** Timer register block definition (struct wd_timer_regblk) |
| * |
| * dcntr and limit registers (halfword access): |
| * ------------------- |
| * | 15 | ...| 1 | 0 | |
| * ------------------- |
| * |- counter val -| |
| * ------------------- |
| * dcntr - Current 16-bit downcounter value. |
| * When downcounter reaches '0' watchdog expires. |
| * Reading this register resets downcounter with |
| * 'limit' value. |
| * limit - 16-bit countdown value in 1/10th second increments. |
| * Writing this register begins countdown with input value. |
| * Reading from this register does not affect counter. |
| * NOTES: After watchdog reset, dcntr and limit contain '1' |
| * |
| * status register (byte access): |
| * --------------------------- |
| * | 7 | ... | 2 | 1 | 0 | |
| * --------------+------------ |
| * |- UNUSED -| EXP | RUN | |
| * --------------------------- |
| * status- Bit 0 - Watchdog is running |
| * Bit 1 - Watchdog has expired |
| * |
| *** PLD register block definition (struct wd_pld_regblk) |
| * |
| * intr_mask register (byte access): |
| * --------------------------------- |
| * | 7 | ... | 3 | 2 | 1 | 0 | |
| * +-------------+------------------ |
| * |- UNUSED -| WD3 | WD2 | WD1 | |
| * --------------------------------- |
| * WD3 - 1 == Interrupt disabled for watchdog 3 |
| * WD2 - 1 == Interrupt disabled for watchdog 2 |
| * WD1 - 1 == Interrupt disabled for watchdog 1 |
| * |
| * pld_status register (byte access): |
| * UNKNOWN, MAGICAL MYSTERY REGISTER |
| * |
| */ |
| #define WD_TIMER_REGSZ 16 |
| #define WD0_OFF 0 |
| #define WD1_OFF (WD_TIMER_REGSZ * 1) |
| #define WD2_OFF (WD_TIMER_REGSZ * 2) |
| #define PLD_OFF (WD_TIMER_REGSZ * 3) |
| |
| #define WD_DCNTR 0x00 |
| #define WD_LIMIT 0x04 |
| #define WD_STATUS 0x08 |
| |
| #define PLD_IMASK (PLD_OFF + 0x00) |
| #define PLD_STATUS (PLD_OFF + 0x04) |
| |
| static struct timer_list cpwd_timer; |
| |
| static int wd0_timeout; |
| static int wd1_timeout; |
| static int wd2_timeout; |
| |
| module_param(wd0_timeout, int, 0); |
| MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs"); |
| module_param(wd1_timeout, int, 0); |
| MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs"); |
| module_param(wd2_timeout, int, 0); |
| MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs"); |
| |
| MODULE_AUTHOR("Eric Brower <ebrower@usa.net>"); |
| MODULE_DESCRIPTION("Hardware watchdog driver for Sun Microsystems CP1400/1500"); |
| MODULE_LICENSE("GPL"); |
| MODULE_SUPPORTED_DEVICE("watchdog"); |
| |
| static void cpwd_writew(u16 val, void __iomem *addr) |
| { |
| writew(cpu_to_le16(val), addr); |
| } |
| static u16 cpwd_readw(void __iomem *addr) |
| { |
| u16 val = readw(addr); |
| |
| return le16_to_cpu(val); |
| } |
| |
| static void cpwd_writeb(u8 val, void __iomem *addr) |
| { |
| writeb(val, addr); |
| } |
| |
| static u8 cpwd_readb(void __iomem *addr) |
| { |
| return readb(addr); |
| } |
| |
| /* Enable or disable watchdog interrupts |
| * Because of the CP1400 defect this should only be |
| * called during initialzation or by wd_[start|stop]timer() |
| * |
| * index - sub-device index, or -1 for 'all' |
| * enable - non-zero to enable interrupts, zero to disable |
| */ |
| static void cpwd_toggleintr(struct cpwd *p, int index, int enable) |
| { |
| unsigned char curregs = cpwd_readb(p->regs + PLD_IMASK); |
| unsigned char setregs = |
| (index == -1) ? |
| (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) : |
| (p->devs[index].intr_mask); |
| |
| if (enable == WD_INTR_ON) |
| curregs &= ~setregs; |
| else |
| curregs |= setregs; |
| |
| cpwd_writeb(curregs, p->regs + PLD_IMASK); |
| } |
| |
| /* Restarts timer with maximum limit value and |
| * does not unset 'brokenstop' value. |
| */ |
| static void cpwd_resetbrokentimer(struct cpwd *p, int index) |
| { |
| cpwd_toggleintr(p, index, WD_INTR_ON); |
| cpwd_writew(WD_BLIMIT, p->devs[index].regs + WD_LIMIT); |
| } |
| |
| /* Timer method called to reset stopped watchdogs-- |
| * because of the PLD bug on CP1400, we cannot mask |
| * interrupts within the PLD so me must continually |
| * reset the timers ad infinitum. |
| */ |
| static void cpwd_brokentimer(struct timer_list *unused) |
| { |
| struct cpwd *p = cpwd_device; |
| int id, tripped = 0; |
| |
| /* kill a running timer instance, in case we |
| * were called directly instead of by kernel timer |
| */ |
| if (timer_pending(&cpwd_timer)) |
| del_timer(&cpwd_timer); |
| |
| for (id = 0; id < WD_NUMDEVS; id++) { |
| if (p->devs[id].runstatus & WD_STAT_BSTOP) { |
| ++tripped; |
| cpwd_resetbrokentimer(p, id); |
| } |
| } |
| |
| if (tripped) { |
| /* there is at least one timer brokenstopped-- reschedule */ |
| cpwd_timer.expires = WD_BTIMEOUT; |
| add_timer(&cpwd_timer); |
| } |
| } |
| |
| /* Reset countdown timer with 'limit' value and continue countdown. |
| * This will not start a stopped timer. |
| */ |
| static void cpwd_pingtimer(struct cpwd *p, int index) |
| { |
| if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) |
| cpwd_readw(p->devs[index].regs + WD_DCNTR); |
| } |
| |
| /* Stop a running watchdog timer-- the timer actually keeps |
| * running, but the interrupt is masked so that no action is |
| * taken upon expiration. |
| */ |
| static void cpwd_stoptimer(struct cpwd *p, int index) |
| { |
| if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) { |
| cpwd_toggleintr(p, index, WD_INTR_OFF); |
| |
| if (p->broken) { |
| p->devs[index].runstatus |= WD_STAT_BSTOP; |
| cpwd_brokentimer(NULL); |
| } |
| } |
| } |
| |
| /* Start a watchdog timer with the specified limit value |
| * If the watchdog is running, it will be restarted with |
| * the provided limit value. |
| * |
| * This function will enable interrupts on the specified |
| * watchdog. |
| */ |
| static void cpwd_starttimer(struct cpwd *p, int index) |
| { |
| if (p->broken) |
| p->devs[index].runstatus &= ~WD_STAT_BSTOP; |
| |
| p->devs[index].runstatus &= ~WD_STAT_SVCD; |
| |
| cpwd_writew(p->devs[index].timeout, p->devs[index].regs + WD_LIMIT); |
| cpwd_toggleintr(p, index, WD_INTR_ON); |
| } |
| |
| static int cpwd_getstatus(struct cpwd *p, int index) |
| { |
| unsigned char stat = cpwd_readb(p->devs[index].regs + WD_STATUS); |
| unsigned char intr = cpwd_readb(p->devs[index].regs + PLD_IMASK); |
| unsigned char ret = WD_STOPPED; |
| |
| /* determine STOPPED */ |
| if (!stat) |
| return ret; |
| |
| /* determine EXPIRED vs FREERUN vs RUNNING */ |
| else if (WD_S_EXPIRED & stat) { |
| ret = WD_EXPIRED; |
| } else if (WD_S_RUNNING & stat) { |
| if (intr & p->devs[index].intr_mask) { |
| ret = WD_FREERUN; |
| } else { |
| /* Fudge WD_EXPIRED status for defective CP1400-- |
| * IF timer is running |
| * AND brokenstop is set |
| * AND an interrupt has been serviced |
| * we are WD_EXPIRED. |
| * |
| * IF timer is running |
| * AND brokenstop is set |
| * AND no interrupt has been serviced |
| * we are WD_FREERUN. |
| */ |
| if (p->broken && |
| (p->devs[index].runstatus & WD_STAT_BSTOP)) { |
| if (p->devs[index].runstatus & WD_STAT_SVCD) { |
| ret = WD_EXPIRED; |
| } else { |
| /* we could as well pretend |
| * we are expired */ |
| ret = WD_FREERUN; |
| } |
| } else { |
| ret = WD_RUNNING; |
| } |
| } |
| } |
| |
| /* determine SERVICED */ |
| if (p->devs[index].runstatus & WD_STAT_SVCD) |
| ret |= WD_SERVICED; |
| |
| return ret; |
| } |
| |
| static irqreturn_t cpwd_interrupt(int irq, void *dev_id) |
| { |
| struct cpwd *p = dev_id; |
| |
| /* Only WD0 will interrupt-- others are NMI and we won't |
| * see them here.... |
| */ |
| spin_lock_irq(&p->lock); |
| |
| cpwd_stoptimer(p, WD0_ID); |
| p->devs[WD0_ID].runstatus |= WD_STAT_SVCD; |
| |
| spin_unlock_irq(&p->lock); |
| |
| return IRQ_HANDLED; |
| } |
| |
| static int cpwd_open(struct inode *inode, struct file *f) |
| { |
| struct cpwd *p = cpwd_device; |
| |
| mutex_lock(&cpwd_mutex); |
| switch (iminor(inode)) { |
| case WD0_MINOR: |
| case WD1_MINOR: |
| case WD2_MINOR: |
| break; |
| |
| default: |
| mutex_unlock(&cpwd_mutex); |
| return -ENODEV; |
| } |
| |
| /* Register IRQ on first open of device */ |
| if (!p->initialized) { |
| if (request_irq(p->irq, &cpwd_interrupt, |
| IRQF_SHARED, DRIVER_NAME, p)) { |
| pr_err("Cannot register IRQ %d\n", p->irq); |
| mutex_unlock(&cpwd_mutex); |
| return -EBUSY; |
| } |
| p->initialized = true; |
| } |
| |
| mutex_unlock(&cpwd_mutex); |
| |
| return stream_open(inode, f); |
| } |
| |
| static int cpwd_release(struct inode *inode, struct file *file) |
| { |
| return 0; |
| } |
| |
| static long cpwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| static const struct watchdog_info info = { |
| .options = WDIOF_SETTIMEOUT, |
| .firmware_version = 1, |
| .identity = DRIVER_NAME, |
| }; |
| void __user *argp = (void __user *)arg; |
| struct inode *inode = file_inode(file); |
| int index = iminor(inode) - WD0_MINOR; |
| struct cpwd *p = cpwd_device; |
| int setopt = 0; |
| |
| switch (cmd) { |
| /* Generic Linux IOCTLs */ |
| case WDIOC_GETSUPPORT: |
| if (copy_to_user(argp, &info, sizeof(struct watchdog_info))) |
| return -EFAULT; |
| break; |
| |
| case WDIOC_GETSTATUS: |
| case WDIOC_GETBOOTSTATUS: |
| if (put_user(0, (int __user *)argp)) |
| return -EFAULT; |
| break; |
| |
| case WDIOC_KEEPALIVE: |
| cpwd_pingtimer(p, index); |
| break; |
| |
| case WDIOC_SETOPTIONS: |
| if (copy_from_user(&setopt, argp, sizeof(unsigned int))) |
| return -EFAULT; |
| |
| if (setopt & WDIOS_DISABLECARD) { |
| if (p->enabled) |
| return -EINVAL; |
| cpwd_stoptimer(p, index); |
| } else if (setopt & WDIOS_ENABLECARD) { |
| cpwd_starttimer(p, index); |
| } else { |
| return -EINVAL; |
| } |
| break; |
| |
| /* Solaris-compatible IOCTLs */ |
| case WIOCGSTAT: |
| setopt = cpwd_getstatus(p, index); |
| if (copy_to_user(argp, &setopt, sizeof(unsigned int))) |
| return -EFAULT; |
| break; |
| |
| case WIOCSTART: |
| cpwd_starttimer(p, index); |
| break; |
| |
| case WIOCSTOP: |
| if (p->enabled) |
| return -EINVAL; |
| |
| cpwd_stoptimer(p, index); |
| break; |
| |
| default: |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| |
| static ssize_t cpwd_write(struct file *file, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| struct inode *inode = file_inode(file); |
| struct cpwd *p = cpwd_device; |
| int index = iminor(inode); |
| |
| if (count) { |
| cpwd_pingtimer(p, index); |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| static ssize_t cpwd_read(struct file *file, char __user *buffer, |
| size_t count, loff_t *ppos) |
| { |
| return -EINVAL; |
| } |
| |
| static const struct file_operations cpwd_fops = { |
| .owner = THIS_MODULE, |
| .unlocked_ioctl = cpwd_ioctl, |
| .compat_ioctl = compat_ptr_ioctl, |
| .open = cpwd_open, |
| .write = cpwd_write, |
| .read = cpwd_read, |
| .release = cpwd_release, |
| .llseek = no_llseek, |
| }; |
| |
| static int cpwd_probe(struct platform_device *op) |
| { |
| struct device_node *options; |
| const char *str_prop; |
| const void *prop_val; |
| int i, err = -EINVAL; |
| struct cpwd *p; |
| |
| if (cpwd_device) |
| return -EINVAL; |
| |
| p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL); |
| if (!p) |
| return -ENOMEM; |
| |
| p->irq = op->archdata.irqs[0]; |
| |
| spin_lock_init(&p->lock); |
| |
| p->regs = of_ioremap(&op->resource[0], 0, |
| 4 * WD_TIMER_REGSZ, DRIVER_NAME); |
| if (!p->regs) { |
| pr_err("Unable to map registers\n"); |
| return -ENOMEM; |
| } |
| |
| options = of_find_node_by_path("/options"); |
| if (!options) { |
| err = -ENODEV; |
| pr_err("Unable to find /options node\n"); |
| goto out_iounmap; |
| } |
| |
| prop_val = of_get_property(options, "watchdog-enable?", NULL); |
| p->enabled = (prop_val ? true : false); |
| |
| prop_val = of_get_property(options, "watchdog-reboot?", NULL); |
| p->reboot = (prop_val ? true : false); |
| |
| str_prop = of_get_property(options, "watchdog-timeout", NULL); |
| if (str_prop) |
| p->timeout = simple_strtoul(str_prop, NULL, 10); |
| |
| of_node_put(options); |
| |
| /* CP1400s seem to have broken PLD implementations-- the |
| * interrupt_mask register cannot be written, so no timer |
| * interrupts can be masked within the PLD. |
| */ |
| str_prop = of_get_property(op->dev.of_node, "model", NULL); |
| p->broken = (str_prop && !strcmp(str_prop, WD_BADMODEL)); |
| |
| if (!p->enabled) |
| cpwd_toggleintr(p, -1, WD_INTR_OFF); |
| |
| for (i = 0; i < WD_NUMDEVS; i++) { |
| static const char *cpwd_names[] = { "RIC", "XIR", "POR" }; |
| static int *parms[] = { &wd0_timeout, |
| &wd1_timeout, |
| &wd2_timeout }; |
| struct miscdevice *mp = &p->devs[i].misc; |
| |
| mp->minor = WD0_MINOR + i; |
| mp->name = cpwd_names[i]; |
| mp->fops = &cpwd_fops; |
| |
| p->devs[i].regs = p->regs + (i * WD_TIMER_REGSZ); |
| p->devs[i].intr_mask = (WD0_INTR_MASK << i); |
| p->devs[i].runstatus &= ~WD_STAT_BSTOP; |
| p->devs[i].runstatus |= WD_STAT_INIT; |
| p->devs[i].timeout = p->timeout; |
| if (*parms[i]) |
| p->devs[i].timeout = *parms[i]; |
| |
| err = misc_register(&p->devs[i].misc); |
| if (err) { |
| pr_err("Could not register misc device for dev %d\n", |
| i); |
| goto out_unregister; |
| } |
| } |
| |
| if (p->broken) { |
| timer_setup(&cpwd_timer, cpwd_brokentimer, 0); |
| cpwd_timer.expires = WD_BTIMEOUT; |
| |
| pr_info("PLD defect workaround enabled for model %s\n", |
| WD_BADMODEL); |
| } |
| |
| platform_set_drvdata(op, p); |
| cpwd_device = p; |
| return 0; |
| |
| out_unregister: |
| for (i--; i >= 0; i--) |
| misc_deregister(&p->devs[i].misc); |
| |
| out_iounmap: |
| of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ); |
| |
| return err; |
| } |
| |
| static int cpwd_remove(struct platform_device *op) |
| { |
| struct cpwd *p = platform_get_drvdata(op); |
| int i; |
| |
| for (i = 0; i < WD_NUMDEVS; i++) { |
| misc_deregister(&p->devs[i].misc); |
| |
| if (!p->enabled) { |
| cpwd_stoptimer(p, i); |
| if (p->devs[i].runstatus & WD_STAT_BSTOP) |
| cpwd_resetbrokentimer(p, i); |
| } |
| } |
| |
| if (p->broken) |
| del_timer_sync(&cpwd_timer); |
| |
| if (p->initialized) |
| free_irq(p->irq, p); |
| |
| of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ); |
| |
| cpwd_device = NULL; |
| |
| return 0; |
| } |
| |
| static const struct of_device_id cpwd_match[] = { |
| { |
| .name = "watchdog", |
| }, |
| {}, |
| }; |
| MODULE_DEVICE_TABLE(of, cpwd_match); |
| |
| static struct platform_driver cpwd_driver = { |
| .driver = { |
| .name = DRIVER_NAME, |
| .of_match_table = cpwd_match, |
| }, |
| .probe = cpwd_probe, |
| .remove = cpwd_remove, |
| }; |
| |
| module_platform_driver(cpwd_driver); |