diff options
Diffstat (limited to 'drivers/watchdog/cpwd.c')
| -rw-r--r-- | drivers/watchdog/cpwd.c | 695 |
1 files changed, 695 insertions, 0 deletions
diff --git a/drivers/watchdog/cpwd.c b/drivers/watchdog/cpwd.c new file mode 100644 index 0000000..084dfe9 --- /dev/null +++ b/drivers/watchdog/cpwd.c @@ -0,0 +1,695 @@ +/* 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> + */ + +#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/interrupt.h> +#include <linux/ioport.h> +#include <linux/timer.h> +#include <linux/smp_lock.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_device.h> + +#include <asm/irq.h> +#include <asm/uaccess.h> + +#include <asm/watchdog.h> + +#define DRIVER_NAME "cpwd" +#define PFX DRIVER_NAME ": " + +#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 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 = 0; +static int wd1_timeout = 0; +static int wd2_timeout = 0; + +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(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; + + lock_kernel(); + switch(iminor(inode)) { + case WD0_MINOR: + case WD1_MINOR: + case WD2_MINOR: + break; + + default: + unlock_kernel(); + return -ENODEV; + } + + /* Register IRQ on first open of device */ + if (!p->initialized) { + if (request_irq(p->irq, &cpwd_interrupt, + IRQF_SHARED, DRIVER_NAME, p)) { + printk(KERN_ERR PFX "Cannot register IRQ %d\n", + p->irq); + unlock_kernel(); + return -EBUSY; + } + p->initialized = true; + } + + unlock_kernel(); + + return nonseekable_open(inode, f); +} + +static int cpwd_release(struct inode *inode, struct file *file) +{ + return 0; +} + +static int cpwd_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + static struct watchdog_info info = { + .options = WDIOF_SETTIMEOUT, + .firmware_version = 1, + .identity = DRIVER_NAME, + }; + void __user *argp = (void __user *)arg; + 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: + lock_kernel(); + rval = cpwd_ioctl(file->f_path.dentry->d_inode, file, cmd, arg); + unlock_kernel(); + 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->f_path.dentry->d_inode; + 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, + .ioctl = cpwd_ioctl, + .compat_ioctl = cpwd_compat_ioctl, + .open = cpwd_open, + .write = cpwd_write, + .read = cpwd_read, + .release = cpwd_release, +}; + +static int __devinit cpwd_probe(struct of_device *op, + const struct of_device_id *match) +{ + 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) { + printk(KERN_ERR PFX "Unable to allocate struct cpwd.\n"); + goto out; + } + + p->irq = op->irqs[0]; + + spin_lock_init(&p->lock); + + p->regs = of_ioremap(&op->resource[0], 0, + 4 * WD_TIMER_REGSZ, DRIVER_NAME); + if (!p->regs) { + printk(KERN_ERR PFX "Unable to map registers.\n"); + goto out_free; + } + + options = of_find_node_by_path("/options"); + err = -ENODEV; + if (!options) { + printk(KERN_ERR PFX "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->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) { + printk(KERN_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; + + printk(KERN_INFO PFX "PLD defect workaround enabled for " + "model " WD_BADMODEL ".\n"); + } + + 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 __devexit cpwd_remove(struct of_device *op) +{ + struct cpwd *p = dev_get_drvdata(&op->dev); + int i; + + for (i = 0; i < 4; 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 of_platform_driver cpwd_driver = { + .name = DRIVER_NAME, + .match_table = cpwd_match, + .probe = cpwd_probe, + .remove = __devexit_p(cpwd_remove), +}; + +static int __init cpwd_init(void) +{ + return of_register_driver(&cpwd_driver, &of_bus_type); +} + +static void __exit cpwd_exit(void) +{ + of_unregister_driver(&cpwd_driver); +} + +module_init(cpwd_init); +module_exit(cpwd_exit); |
