/* cpwatchdog.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. * * TODO: DevFS support (/dev/watchdogs/0 ... /dev/watchdogs/2) * * Copyright (c) 2000 Eric Brower (ebrower@usa.net) */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/fs.h> #include <linux/errno.h> #include <linux/major.h> #include <linux/init.h> #include <linux/miscdevice.h> #include <linux/sched.h> #include <linux/interrupt.h> #include <linux/ioport.h> #include <linux/timer.h> #include <asm/irq.h> #include <asm/ebus.h> #include <asm/oplib.h> #include <asm/uaccess.h> #include <asm/watchdog.h> #define WD_OBPNAME "watchdog" #define WD_BADMODEL "SUNW,501-5336" #define WD_BTIMEOUT (jiffies + (HZ * 1000)) #define WD_BLIMIT 0xFFFF #define WD0_DEVNAME "watchdog0" #define WD1_DEVNAME "watchdog1" #define WD2_DEVNAME "watchdog2" #define WD0_MINOR 212 #define WD1_MINOR 213 #define WD2_MINOR 214 /* Internal driver definitions */ #define WD0_ID 0 /* Watchdog0 */ #define WD1_ID 1 /* Watchdog1 */ #define WD2_ID 2 /* Watchdog2 */ #define WD_NUMDEVS 3 /* Device contains 3 timers */ #define WD_INTR_OFF 0 /* Interrupt disable value */ #define WD_INTR_ON 1 /* Interrupt enable value */ #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 */ /* 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) /* Individual timer structure */ struct wd_timer { __u16 timeout; __u8 intr_mask; unsigned char runstatus; void __iomem *regs; }; /* Device structure */ struct wd_device { int irq; spinlock_t lock; unsigned char isbaddoggie; /* defective PLD */ unsigned char opt_enable; unsigned char opt_reboot; unsigned short opt_timeout; unsigned char initialized; struct wd_timer watchdog[WD_NUMDEVS]; void __iomem *regs; }; static struct wd_device wd_dev = { 0, SPIN_LOCK_UNLOCKED, 0, 0, 0, 0, }; static struct timer_list wd_timer; static int wd0_timeout = 0; static int wd1_timeout = 0; static int wd2_timeout = 0; #ifdef MODULE 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"); #endif /* ifdef MODULE */ /* Forward declarations of internal methods */ #ifdef WD_DEBUG static void wd_dumpregs(void); #endif static irqreturn_t wd_interrupt(int irq, void *dev_id, struct pt_regs *regs); static void wd_toggleintr(struct wd_timer* pTimer, int enable); static void wd_pingtimer(struct wd_timer* pTimer); static void wd_starttimer(struct wd_timer* pTimer); static void wd_resetbrokentimer(struct wd_timer* pTimer); static void wd_stoptimer(struct wd_timer* pTimer); static void wd_brokentimer(unsigned long data); static int wd_getstatus(struct wd_timer* pTimer); /* PLD expects words to be written in LSB format, * so we must flip all words prior to writing them to regs */ static inline unsigned short flip_word(unsigned short word) { return ((word & 0xff) << 8) | ((word >> 8) & 0xff); } #define wd_writew(val, addr) (writew(flip_word(val), addr)) #define wd_readw(addr) (flip_word(readw(addr))) #define wd_writeb(val, addr) (writeb(val, addr)) #define wd_readb(addr) (readb(addr)) /* CP1400s seem to have broken PLD implementations-- * the interrupt_mask register cannot be written, so * no timer interrupts can be masked within the PLD. */ static inline int wd_isbroken(void) { /* we could test this by read/write/read/restore * on the interrupt mask register only if OBP * 'watchdog-enable?' == FALSE, but it seems * ubiquitous on CP1400s */ char val[32]; prom_getproperty(prom_root_node, "model", val, sizeof(val)); return((!strcmp(val, WD_BADMODEL)) ? 1 : 0); } /* Retrieve watchdog-enable? option from OBP * Returns 0 if false, 1 if true */ static inline int wd_opt_enable(void) { int opt_node; opt_node = prom_getchild(prom_root_node); opt_node = prom_searchsiblings(opt_node, "options"); return((-1 == prom_getint(opt_node, "watchdog-enable?")) ? 0 : 1); } /* Retrieve watchdog-reboot? option from OBP * Returns 0 if false, 1 if true */ static inline int wd_opt_reboot(void) { int opt_node; opt_node = prom_getchild(prom_root_node); opt_node = prom_searchsiblings(opt_node, "options"); return((-1 == prom_getint(opt_node, "watchdog-reboot?")) ? 0 : 1); } /* Retrieve watchdog-timeout option from OBP * Returns OBP value, or 0 if not located */ static inline int wd_opt_timeout(void) { int opt_node; char value[32]; char *p = value; opt_node = prom_getchild(prom_root_node); opt_node = prom_searchsiblings(opt_node, "options"); opt_node = prom_getproperty(opt_node, "watchdog-timeout", value, sizeof(value)); if(-1 != opt_node) { /* atoi implementation */ for(opt_node = 0; /* nop */; p++) { if(*p >= '0' && *p <= '9') { opt_node = (10*opt_node)+(*p-'0'); } else { break; } } } return((-1 == opt_node) ? (0) : (opt_node)); } static int wd_open(struct inode *inode, struct file *f) { switch(iminor(inode)) { case WD0_MINOR: f->private_data = &wd_dev.watchdog[WD0_ID]; break; case WD1_MINOR: f->private_data = &wd_dev.watchdog[WD1_ID]; break; case WD2_MINOR: f->private_data = &wd_dev.watchdog[WD2_ID]; break; default: return(-ENODEV); } /* Register IRQ on first open of device */ if(0 == wd_dev.initialized) { if (request_irq(wd_dev.irq, &wd_interrupt, SA_SHIRQ, WD_OBPNAME, (void *)wd_dev.regs)) { printk("%s: Cannot register IRQ %s\n", WD_OBPNAME, __irq_itoa(wd_dev.irq)); return(-EBUSY); } wd_dev.initialized = 1; } return(nonseekable_open(inode, f)); } static int wd_release(struct inode *inode, struct file *file) { return 0; } static int wd_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { int setopt = 0; struct wd_timer* pTimer = (struct wd_timer*)file->private_data; void __user *argp = (void __user *)arg; struct watchdog_info info = { 0, 0, "Altera EPF8820ATC144-4" }; if(NULL == pTimer) { return(-EINVAL); } 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: wd_pingtimer(pTimer); break; case WDIOC_SETOPTIONS: if(copy_from_user(&setopt, argp, sizeof(unsigned int))) { return -EFAULT; } if(setopt & WDIOS_DISABLECARD) { if(wd_dev.opt_enable) { printk( "%s: cannot disable watchdog in ENABLED mode\n", WD_OBPNAME); return(-EINVAL); } wd_stoptimer(pTimer); } else if(setopt & WDIOS_ENABLECARD) { wd_starttimer(pTimer); } else { return(-EINVAL); } break; /* Solaris-compatible IOCTLs */ case WIOCGSTAT: setopt = wd_getstatus(pTimer); if(copy_to_user(argp, &setopt, sizeof(unsigned int))) { return(-EFAULT); } break; case WIOCSTART: wd_starttimer(pTimer); break; case WIOCSTOP: if(wd_dev.opt_enable) { printk("%s: cannot disable watchdog in ENABLED mode\n", WD_OBPNAME); return(-EINVAL); } wd_stoptimer(pTimer); break; default: return(-EINVAL); } return(0); } static ssize_t wd_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct wd_timer* pTimer = (struct wd_timer*)file->private_data; if(NULL == pTimer) { return(-EINVAL); } if (count) { wd_pingtimer(pTimer); return 1; } return 0; } static ssize_t wd_read(struct file * file, char __user *buffer, size_t count, loff_t *ppos) { #ifdef WD_DEBUG wd_dumpregs(); return(0); #else return(-EINVAL); #endif /* ifdef WD_DEBUG */ } static irqreturn_t wd_interrupt(int irq, void *dev_id, struct pt_regs *regs) { /* Only WD0 will interrupt-- others are NMI and we won't * see them here.... */ spin_lock_irq(&wd_dev.lock); if((unsigned long)wd_dev.regs == (unsigned long)dev_id) { wd_stoptimer(&wd_dev.watchdog[WD0_ID]); wd_dev.watchdog[WD0_ID].runstatus |= WD_STAT_SVCD; } spin_unlock_irq(&wd_dev.lock); return IRQ_HANDLED; } static struct file_operations wd_fops = { .owner = THIS_MODULE, .ioctl = wd_ioctl, .open = wd_open, .write = wd_write, .read = wd_read, .release = wd_release, }; static struct miscdevice wd0_miscdev = { WD0_MINOR, WD0_DEVNAME, &wd_fops }; static struct miscdevice wd1_miscdev = { WD1_MINOR, WD1_DEVNAME, &wd_fops }; static struct miscdevice wd2_miscdev = { WD2_MINOR, WD2_DEVNAME, &wd_fops }; #ifdef WD_DEBUG static void wd_dumpregs(void) { /* Reading from downcounters initiates watchdog countdown-- * Example is included below for illustration purposes. */ int i; printk("%s: dumping register values\n", WD_OBPNAME); for(i = WD0_ID; i < WD_NUMDEVS; ++i) { /* printk("\t%s%i: dcntr at 0x%lx: 0x%x\n", * WD_OBPNAME, * i, * (unsigned long)(&wd_dev.watchdog[i].regs->dcntr), * readw(&wd_dev.watchdog[i].regs->dcntr)); */ printk("\t%s%i: limit at 0x%lx: 0x%x\n", WD_OBPNAME, i, (unsigned long)(&wd_dev.watchdog[i].regs->limit), readw(&wd_dev.watchdog[i].regs->limit)); printk("\t%s%i: status at 0x%lx: 0x%x\n", WD_OBPNAME, i, (unsigned long)(&wd_dev.watchdog[i].regs->status), readb(&wd_dev.watchdog[i].regs->status)); printk("\t%s%i: driver status: 0x%x\n", WD_OBPNAME, i, wd_getstatus(&wd_dev.watchdog[i])); } printk("\tintr_mask at %p: 0x%x\n", wd_dev.regs + PLD_IMASK, readb(wd_dev.regs + PLD_IMASK)); printk("\tpld_status at %p: 0x%x\n", wd_dev.regs + PLD_STATUS, readb(wd_dev.regs + PLD_STATUS)); } #endif /* Enable or disable watchdog interrupts * Because of the CP1400 defect this should only be * called during initialzation or by wd_[start|stop]timer() * * pTimer - pointer to timer device, or NULL to indicate all timers * enable - non-zero to enable interrupts, zero to disable */ static void wd_toggleintr(struct wd_timer* pTimer, int enable) { unsigned char curregs = wd_readb(wd_dev.regs + PLD_IMASK); unsigned char setregs = (NULL == pTimer) ? (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) : (pTimer->intr_mask); (WD_INTR_ON == enable) ? (curregs &= ~setregs): (curregs |= setregs); wd_writeb(curregs, wd_dev.regs + PLD_IMASK); return; } /* Reset countdown timer with 'limit' value and continue countdown. * This will not start a stopped timer. * * pTimer - pointer to timer device */ static void wd_pingtimer(struct wd_timer* pTimer) { if (wd_readb(pTimer->regs + WD_STATUS) & WD_S_RUNNING) { wd_readw(pTimer->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. * * pTimer - pointer to timer device */ static void wd_stoptimer(struct wd_timer* pTimer) { if(wd_readb(pTimer->regs + WD_STATUS) & WD_S_RUNNING) { wd_toggleintr(pTimer, WD_INTR_OFF); if(wd_dev.isbaddoggie) { pTimer->runstatus |= WD_STAT_BSTOP; wd_brokentimer((unsigned long)&wd_dev); } } } /* 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. * * pTimer - pointer to timer device * limit - limit (countdown) value in 1/10th seconds */ static void wd_starttimer(struct wd_timer* pTimer) { if(wd_dev.isbaddoggie) { pTimer->runstatus &= ~WD_STAT_BSTOP; } pTimer->runstatus &= ~WD_STAT_SVCD; wd_writew(pTimer->timeout, pTimer->regs + WD_LIMIT); wd_toggleintr(pTimer, WD_INTR_ON); } /* Restarts timer with maximum limit value and * does not unset 'brokenstop' value. */ static void wd_resetbrokentimer(struct wd_timer* pTimer) { wd_toggleintr(pTimer, WD_INTR_ON); wd_writew(WD_BLIMIT, pTimer->regs + WD_LIMIT); } /* Timer device initialization helper. * Returns 0 on success, other on failure */ static int wd_inittimer(int whichdog) { struct miscdevice *whichmisc; void __iomem *whichregs; char whichident[8]; int whichmask; __u16 whichlimit; switch(whichdog) { case WD0_ID: whichmisc = &wd0_miscdev; strcpy(whichident, "RIC"); whichregs = wd_dev.regs + WD0_OFF; whichmask = WD0_INTR_MASK; whichlimit= (0 == wd0_timeout) ? (wd_dev.opt_timeout): (wd0_timeout); break; case WD1_ID: whichmisc = &wd1_miscdev; strcpy(whichident, "XIR"); whichregs = wd_dev.regs + WD1_OFF; whichmask = WD1_INTR_MASK; whichlimit= (0 == wd1_timeout) ? (wd_dev.opt_timeout): (wd1_timeout); break; case WD2_ID: whichmisc = &wd2_miscdev; strcpy(whichident, "POR"); whichregs = wd_dev.regs + WD2_OFF; whichmask = WD2_INTR_MASK; whichlimit= (0 == wd2_timeout) ? (wd_dev.opt_timeout): (wd2_timeout); break; default: printk("%s: %s: invalid watchdog id: %i\n", WD_OBPNAME, __FUNCTION__, whichdog); return(1); } if(0 != misc_register(whichmisc)) { return(1); } wd_dev.watchdog[whichdog].regs = whichregs; wd_dev.watchdog[whichdog].timeout = whichlimit; wd_dev.watchdog[whichdog].intr_mask = whichmask; wd_dev.watchdog[whichdog].runstatus &= ~WD_STAT_BSTOP; wd_dev.watchdog[whichdog].runstatus |= WD_STAT_INIT; printk("%s%i: %s hardware watchdog [%01i.%i sec] %s\n", WD_OBPNAME, whichdog, whichident, wd_dev.watchdog[whichdog].timeout / 10, wd_dev.watchdog[whichdog].timeout % 10, (0 != wd_dev.opt_enable) ? "in ENABLED mode" : ""); return(0); } /* 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 wd_brokentimer(unsigned long data) { struct wd_device* pDev = (struct wd_device*)data; int id, tripped = 0; /* kill a running timer instance, in case we * were called directly instead of by kernel timer */ if(timer_pending(&wd_timer)) { del_timer(&wd_timer); } for(id = WD0_ID; id < WD_NUMDEVS; ++id) { if(pDev->watchdog[id].runstatus & WD_STAT_BSTOP) { ++tripped; wd_resetbrokentimer(&pDev->watchdog[id]); } } if(tripped) { /* there is at least one timer brokenstopped-- reschedule */ init_timer(&wd_timer); wd_timer.expires = WD_BTIMEOUT; add_timer(&wd_timer); } } static int wd_getstatus(struct wd_timer* pTimer) { unsigned char stat = wd_readb(pTimer->regs + WD_STATUS); unsigned char intr = wd_readb(wd_dev.regs + PLD_IMASK); unsigned char ret = WD_STOPPED; /* determine STOPPED */ if(0 == 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 & pTimer->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(wd_dev.isbaddoggie && (pTimer->runstatus & WD_STAT_BSTOP)) { if(pTimer->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(pTimer->runstatus & WD_STAT_SVCD) { ret |= WD_SERVICED; } return(ret); } static int __init wd_init(void) { int id; struct linux_ebus *ebus = NULL; struct linux_ebus_device *edev = NULL; for_each_ebus(ebus) { for_each_ebusdev(edev, ebus) { if (!strcmp(edev->prom_name, WD_OBPNAME)) goto ebus_done; } } ebus_done: if(!edev) { printk("%s: unable to locate device\n", WD_OBPNAME); return -ENODEV; } wd_dev.regs = ioremap(edev->resource[0].start, 4 * WD_TIMER_REGSZ); /* ? */ if(NULL == wd_dev.regs) { printk("%s: unable to map registers\n", WD_OBPNAME); return(-ENODEV); } /* initialize device structure from OBP parameters */ wd_dev.irq = edev->irqs[0]; wd_dev.opt_enable = wd_opt_enable(); wd_dev.opt_reboot = wd_opt_reboot(); wd_dev.opt_timeout = wd_opt_timeout(); wd_dev.isbaddoggie = wd_isbroken(); /* disable all interrupts unless watchdog-enabled? == true */ if(! wd_dev.opt_enable) { wd_toggleintr(NULL, WD_INTR_OFF); } /* register miscellaneous devices */ for(id = WD0_ID; id < WD_NUMDEVS; ++id) { if(0 != wd_inittimer(id)) { printk("%s%i: unable to initialize\n", WD_OBPNAME, id); } } /* warn about possible defective PLD */ if(wd_dev.isbaddoggie) { init_timer(&wd_timer); wd_timer.function = wd_brokentimer; wd_timer.data = (unsigned long)&wd_dev; wd_timer.expires = WD_BTIMEOUT; printk("%s: PLD defect workaround enabled for model %s\n", WD_OBPNAME, WD_BADMODEL); } return(0); } static void __exit wd_cleanup(void) { int id; /* if 'watchdog-enable?' == TRUE, timers are not stopped * when module is unloaded. All brokenstopped timers will * also now eventually trip. */ for(id = WD0_ID; id < WD_NUMDEVS; ++id) { if(WD_S_RUNNING == wd_readb(wd_dev.watchdog[id].regs + WD_STATUS)) { if(wd_dev.opt_enable) { printk(KERN_WARNING "%s%i: timer not stopped at release\n", WD_OBPNAME, id); } else { wd_stoptimer(&wd_dev.watchdog[id]); if(wd_dev.watchdog[id].runstatus & WD_STAT_BSTOP) { wd_resetbrokentimer(&wd_dev.watchdog[id]); printk(KERN_WARNING "%s%i: defect workaround disabled at release, "\ "timer expires in ~%01i sec\n", WD_OBPNAME, id, wd_readw(wd_dev.watchdog[id].regs + WD_LIMIT) / 10); } } } } if(wd_dev.isbaddoggie && timer_pending(&wd_timer)) { del_timer(&wd_timer); } if(0 != (wd_dev.watchdog[WD0_ID].runstatus & WD_STAT_INIT)) { misc_deregister(&wd0_miscdev); } if(0 != (wd_dev.watchdog[WD1_ID].runstatus & WD_STAT_INIT)) { misc_deregister(&wd1_miscdev); } if(0 != (wd_dev.watchdog[WD2_ID].runstatus & WD_STAT_INIT)) { misc_deregister(&wd2_miscdev); } if(0 != wd_dev.initialized) { free_irq(wd_dev.irq, (void *)wd_dev.regs); } iounmap(wd_dev.regs); } module_init(wd_init); module_exit(wd_cleanup);