/* 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 */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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 "); 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(unsigned long data) { struct cpwd *p = (struct cpwd *) data; 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((unsigned long) p); } } } /* 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 nonseekable_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 long cpwd_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int rval = -ENOIOCTLCMD; switch (cmd) { /* solaris ioctls are specific to this driver */ case WIOCSTART: case WIOCSTOP: case WIOCGSTAT: mutex_lock(&cpwd_mutex); rval = cpwd_ioctl(file, cmd, arg); mutex_unlock(&cpwd_mutex); break; /* everything else is handled by the generic compat layer */ default: break; } return rval; } 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 = cpwd_compat_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 = kzalloc(sizeof(*p), GFP_KERNEL); err = -ENOMEM; if (!p) { pr_err("Unable to allocate struct cpwd\n"); goto out; } 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"); goto out_free; } options = of_find_node_by_path("/options"); err = -ENODEV; if (!options) { 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); /* 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) { init_timer(&cpwd_timer); cpwd_timer.function = cpwd_brokentimer; cpwd_timer.data = (unsigned long) p; cpwd_timer.expires = WD_BTIMEOUT; pr_info("PLD defect workaround enabled for model %s\n", WD_BADMODEL); } dev_set_drvdata(&op->dev, p); cpwd_device = p; err = 0; out: return err; 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); out_free: kfree(p); goto out; } static int cpwd_remove(struct platform_device *op) { struct cpwd *p = dev_get_drvdata(&op->dev); 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); kfree(p); 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, .owner = THIS_MODULE, .of_match_table = cpwd_match, }, .probe = cpwd_probe, .remove = cpwd_remove, }; module_platform_driver(cpwd_driver);