/* * Timer device implementation for SGI SN platforms. * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (c) 2001-2006 Silicon Graphics, Inc. All rights reserved. * * This driver exports an API that should be supportable by any HPET or IA-PC * multimedia timer. The code below is currently specific to the SGI Altix * SHub RTC, however. * * 11/01/01 - jbarnes - initial revision * 9/10/04 - Christoph Lameter - remove interrupt support for kernel inclusion * 10/1/04 - Christoph Lameter - provide posix clock CLOCK_SGI_CYCLE * 10/13/04 - Christoph Lameter, Dimitri Sivanich - provide timer interrupt * support via the posix timer interface */ #include <linux/types.h> #include <linux/kernel.h> #include <linux/ioctl.h> #include <linux/module.h> #include <linux/init.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/fs.h> #include <linux/mmtimer.h> #include <linux/miscdevice.h> #include <linux/posix-timers.h> #include <linux/interrupt.h> #include <linux/time.h> #include <linux/math64.h> #include <linux/smp_lock.h> #include <asm/uaccess.h> #include <asm/sn/addrs.h> #include <asm/sn/intr.h> #include <asm/sn/shub_mmr.h> #include <asm/sn/nodepda.h> #include <asm/sn/shubio.h> MODULE_AUTHOR("Jesse Barnes <jbarnes@sgi.com>"); MODULE_DESCRIPTION("SGI Altix RTC Timer"); MODULE_LICENSE("GPL"); /* name of the device, usually in /dev */ #define MMTIMER_NAME "mmtimer" #define MMTIMER_DESC "SGI Altix RTC Timer" #define MMTIMER_VERSION "2.1" #define RTC_BITS 55 /* 55 bits for this implementation */ extern unsigned long sn_rtc_cycles_per_second; #define RTC_COUNTER_ADDR ((long *)LOCAL_MMR_ADDR(SH_RTC)) #define rtc_time() (*RTC_COUNTER_ADDR) static long mmtimer_ioctl(struct file *file, unsigned int cmd, unsigned long arg); static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma); /* * Period in femtoseconds (10^-15 s) */ static unsigned long mmtimer_femtoperiod = 0; static const struct file_operations mmtimer_fops = { .owner = THIS_MODULE, .mmap = mmtimer_mmap, .unlocked_ioctl = mmtimer_ioctl, }; /* * We only have comparison registers RTC1-4 currently available per * node. RTC0 is used by SAL. */ /* Check for an RTC interrupt pending */ static int mmtimer_int_pending(int comparator) { if (HUB_L((unsigned long *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED)) & SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator) return 1; else return 0; } /* Clear the RTC interrupt pending bit */ static void mmtimer_clr_int_pending(int comparator) { HUB_S((u64 *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED_ALIAS), SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator); } /* Setup timer on comparator RTC1 */ static void mmtimer_setup_int_0(int cpu, u64 expires) { u64 val; /* Disable interrupt */ HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 0UL); /* Initialize comparator value */ HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), -1L); /* Clear pending bit */ mmtimer_clr_int_pending(0); val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC1_INT_CONFIG_IDX_SHFT) | ((u64)cpu_physical_id(cpu) << SH_RTC1_INT_CONFIG_PID_SHFT); /* Set configuration */ HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_CONFIG), val); /* Enable RTC interrupts */ HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 1UL); /* Initialize comparator value */ HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), expires); } /* Setup timer on comparator RTC2 */ static void mmtimer_setup_int_1(int cpu, u64 expires) { u64 val; HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 0UL); HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), -1L); mmtimer_clr_int_pending(1); val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC2_INT_CONFIG_IDX_SHFT) | ((u64)cpu_physical_id(cpu) << SH_RTC2_INT_CONFIG_PID_SHFT); HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_CONFIG), val); HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 1UL); HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), expires); } /* Setup timer on comparator RTC3 */ static void mmtimer_setup_int_2(int cpu, u64 expires) { u64 val; HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 0UL); HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), -1L); mmtimer_clr_int_pending(2); val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC3_INT_CONFIG_IDX_SHFT) | ((u64)cpu_physical_id(cpu) << SH_RTC3_INT_CONFIG_PID_SHFT); HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_CONFIG), val); HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 1UL); HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), expires); } /* * This function must be called with interrupts disabled and preemption off * in order to insure that the setup succeeds in a deterministic time frame. * It will check if the interrupt setup succeeded. */ static int mmtimer_setup(int cpu, int comparator, unsigned long expires) { switch (comparator) { case 0: mmtimer_setup_int_0(cpu, expires); break; case 1: mmtimer_setup_int_1(cpu, expires); break; case 2: mmtimer_setup_int_2(cpu, expires); break; } /* We might've missed our expiration time */ if (rtc_time() <= expires) return 1; /* * If an interrupt is already pending then its okay * if not then we failed */ return mmtimer_int_pending(comparator); } static int mmtimer_disable_int(long nasid, int comparator) { switch (comparator) { case 0: nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 0UL) : REMOTE_HUB_S(nasid, SH_RTC1_INT_ENABLE, 0UL); break; case 1: nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 0UL) : REMOTE_HUB_S(nasid, SH_RTC2_INT_ENABLE, 0UL); break; case 2: nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 0UL) : REMOTE_HUB_S(nasid, SH_RTC3_INT_ENABLE, 0UL); break; default: return -EFAULT; } return 0; } #define COMPARATOR 1 /* The comparator to use */ #define TIMER_OFF 0xbadcabLL /* Timer is not setup */ #define TIMER_SET 0 /* Comparator is set for this timer */ /* There is one of these for each timer */ struct mmtimer { struct rb_node list; struct k_itimer *timer; int cpu; }; struct mmtimer_node { spinlock_t lock ____cacheline_aligned; struct rb_root timer_head; struct rb_node *next; struct tasklet_struct tasklet; }; static struct mmtimer_node *timers; /* * Add a new mmtimer struct to the node's mmtimer list. * This function assumes the struct mmtimer_node is locked. */ static void mmtimer_add_list(struct mmtimer *n) { int nodeid = n->timer->it.mmtimer.node; unsigned long expires = n->timer->it.mmtimer.expires; struct rb_node **link = &timers[nodeid].timer_head.rb_node; struct rb_node *parent = NULL; struct mmtimer *x; /* * Find the right place in the rbtree: */ while (*link) { parent = *link; x = rb_entry(parent, struct mmtimer, list); if (expires < x->timer->it.mmtimer.expires) link = &(*link)->rb_left; else link = &(*link)->rb_right; } /* * Insert the timer to the rbtree and check whether it * replaces the first pending timer */ rb_link_node(&n->list, parent, link); rb_insert_color(&n->list, &timers[nodeid].timer_head); if (!timers[nodeid].next || expires < rb_entry(timers[nodeid].next, struct mmtimer, list)->timer->it.mmtimer.expires) timers[nodeid].next = &n->list; } /* * Set the comparator for the next timer. * This function assumes the struct mmtimer_node is locked. */ static void mmtimer_set_next_timer(int nodeid) { struct mmtimer_node *n = &timers[nodeid]; struct mmtimer *x; struct k_itimer *t; int o; restart: if (n->next == NULL) return; x = rb_entry(n->next, struct mmtimer, list); t = x->timer; if (!t->it.mmtimer.incr) { /* Not an interval timer */ if (!mmtimer_setup(x->cpu, COMPARATOR, t->it.mmtimer.expires)) { /* Late setup, fire now */ tasklet_schedule(&n->tasklet); } return; } /* Interval timer */ o = 0; while (!mmtimer_setup(x->cpu, COMPARATOR, t->it.mmtimer.expires)) { unsigned long e, e1; struct rb_node *next; t->it.mmtimer.expires += t->it.mmtimer.incr << o; t->it_overrun += 1 << o; o++; if (o > 20) { printk(KERN_ALERT "mmtimer: cannot reschedule timer\n"); t->it.mmtimer.clock = TIMER_OFF; n->next = rb_next(&x->list); rb_erase(&x->list, &n->timer_head); kfree(x); goto restart; } e = t->it.mmtimer.expires; next = rb_next(&x->list); if (next == NULL) continue; e1 = rb_entry(next, struct mmtimer, list)-> timer->it.mmtimer.expires; if (e > e1) { n->next = next; rb_erase(&x->list, &n->timer_head); mmtimer_add_list(x); goto restart; } } } /** * mmtimer_ioctl - ioctl interface for /dev/mmtimer * @file: file structure for the device * @cmd: command to execute * @arg: optional argument to command * * Executes the command specified by @cmd. Returns 0 for success, < 0 for * failure. * * Valid commands: * * %MMTIMER_GETOFFSET - Should return the offset (relative to the start * of the page where the registers are mapped) for the counter in question. * * %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15) * seconds * * %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address * specified by @arg * * %MMTIMER_GETBITS - Returns the number of bits in the clock's counter * * %MMTIMER_MMAPAVAIL - Returns 1 if the registers can be mmap'd into userspace * * %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it * in the address specified by @arg. */ static long mmtimer_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int ret = 0; lock_kernel(); switch (cmd) { case MMTIMER_GETOFFSET: /* offset of the counter */ /* * SN RTC registers are on their own 64k page */ if(PAGE_SIZE <= (1 << 16)) ret = (((long)RTC_COUNTER_ADDR) & (PAGE_SIZE-1)) / 8; else ret = -ENOSYS; break; case MMTIMER_GETRES: /* resolution of the clock in 10^-15 s */ if(copy_to_user((unsigned long __user *)arg, &mmtimer_femtoperiod, sizeof(unsigned long))) ret = -EFAULT; break; case MMTIMER_GETFREQ: /* frequency in Hz */ if(copy_to_user((unsigned long __user *)arg, &sn_rtc_cycles_per_second, sizeof(unsigned long))) ret = -EFAULT; break; case MMTIMER_GETBITS: /* number of bits in the clock */ ret = RTC_BITS; break; case MMTIMER_MMAPAVAIL: /* can we mmap the clock into userspace? */ ret = (PAGE_SIZE <= (1 << 16)) ? 1 : 0; break; case MMTIMER_GETCOUNTER: if(copy_to_user((unsigned long __user *)arg, RTC_COUNTER_ADDR, sizeof(unsigned long))) ret = -EFAULT; break; default: ret = -ENOTTY; break; } unlock_kernel(); return ret; } /** * mmtimer_mmap - maps the clock's registers into userspace * @file: file structure for the device * @vma: VMA to map the registers into * * Calls remap_pfn_range() to map the clock's registers into * the calling process' address space. */ static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma) { unsigned long mmtimer_addr; if (vma->vm_end - vma->vm_start != PAGE_SIZE) return -EINVAL; if (vma->vm_flags & VM_WRITE) return -EPERM; if (PAGE_SIZE > (1 << 16)) return -ENOSYS; vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); mmtimer_addr = __pa(RTC_COUNTER_ADDR); mmtimer_addr &= ~(PAGE_SIZE - 1); mmtimer_addr &= 0xfffffffffffffffUL; if (remap_pfn_range(vma, vma->vm_start, mmtimer_addr >> PAGE_SHIFT, PAGE_SIZE, vma->vm_page_prot)) { printk(KERN_ERR "remap_pfn_range failed in mmtimer.c\n"); return -EAGAIN; } return 0; } static struct miscdevice mmtimer_miscdev = { SGI_MMTIMER, MMTIMER_NAME, &mmtimer_fops }; static struct timespec sgi_clock_offset; static int sgi_clock_period; /* * Posix Timer Interface */ static struct timespec sgi_clock_offset; static int sgi_clock_period; static int sgi_clock_get(clockid_t clockid, struct timespec *tp) { u64 nsec; nsec = rtc_time() * sgi_clock_period + sgi_clock_offset.tv_nsec; *tp = ns_to_timespec(nsec); tp->tv_sec += sgi_clock_offset.tv_sec; return 0; }; static int sgi_clock_set(clockid_t clockid, struct timespec *tp) { u64 nsec; u32 rem; nsec = rtc_time() * sgi_clock_period; sgi_clock_offset.tv_sec = tp->tv_sec - div_u64_rem(nsec, NSEC_PER_SEC, &rem); if (rem <= tp->tv_nsec) sgi_clock_offset.tv_nsec = tp->tv_sec - rem; else { sgi_clock_offset.tv_nsec = tp->tv_sec + NSEC_PER_SEC - rem; sgi_clock_offset.tv_sec--; } return 0; } /** * mmtimer_interrupt - timer interrupt handler * @irq: irq received * @dev_id: device the irq came from * * Called when one of the comarators matches the counter, This * routine will send signals to processes that have requested * them. * * This interrupt is run in an interrupt context * by the SHUB. It is therefore safe to locally access SHub * registers. */ static irqreturn_t mmtimer_interrupt(int irq, void *dev_id) { unsigned long expires = 0; int result = IRQ_NONE; unsigned indx = cpu_to_node(smp_processor_id()); struct mmtimer *base; spin_lock(&timers[indx].lock); base = rb_entry(timers[indx].next, struct mmtimer, list); if (base == NULL) { spin_unlock(&timers[indx].lock); return result; } if (base->cpu == smp_processor_id()) { if (base->timer) expires = base->timer->it.mmtimer.expires; /* expires test won't work with shared irqs */ if ((mmtimer_int_pending(COMPARATOR) > 0) || (expires && (expires <= rtc_time()))) { mmtimer_clr_int_pending(COMPARATOR); tasklet_schedule(&timers[indx].tasklet); result = IRQ_HANDLED; } } spin_unlock(&timers[indx].lock); return result; } static void mmtimer_tasklet(unsigned long data) { int nodeid = data; struct mmtimer_node *mn = &timers[nodeid]; struct mmtimer *x; struct k_itimer *t; unsigned long flags; /* Send signal and deal with periodic signals */ spin_lock_irqsave(&mn->lock, flags); if (!mn->next) goto out; x = rb_entry(mn->next, struct mmtimer, list); t = x->timer; if (t->it.mmtimer.clock == TIMER_OFF) goto out; t->it_overrun = 0; mn->next = rb_next(&x->list); rb_erase(&x->list, &mn->timer_head); if (posix_timer_event(t, 0) != 0) t->it_overrun++; if(t->it.mmtimer.incr) { t->it.mmtimer.expires += t->it.mmtimer.incr; mmtimer_add_list(x); } else { /* Ensure we don't false trigger in mmtimer_interrupt */ t->it.mmtimer.clock = TIMER_OFF; t->it.mmtimer.expires = 0; kfree(x); } /* Set comparator for next timer, if there is one */ mmtimer_set_next_timer(nodeid); t->it_overrun_last = t->it_overrun; out: spin_unlock_irqrestore(&mn->lock, flags); } static int sgi_timer_create(struct k_itimer *timer) { /* Insure that a newly created timer is off */ timer->it.mmtimer.clock = TIMER_OFF; return 0; } /* This does not really delete a timer. It just insures * that the timer is not active * * Assumption: it_lock is already held with irq's disabled */ static int sgi_timer_del(struct k_itimer *timr) { cnodeid_t nodeid = timr->it.mmtimer.node; unsigned long irqflags; spin_lock_irqsave(&timers[nodeid].lock, irqflags); if (timr->it.mmtimer.clock != TIMER_OFF) { unsigned long expires = timr->it.mmtimer.expires; struct rb_node *n = timers[nodeid].timer_head.rb_node; struct mmtimer *uninitialized_var(t); int r = 0; timr->it.mmtimer.clock = TIMER_OFF; timr->it.mmtimer.expires = 0; while (n) { t = rb_entry(n, struct mmtimer, list); if (t->timer == timr) break; if (expires < t->timer->it.mmtimer.expires) n = n->rb_left; else n = n->rb_right; } if (!n) { spin_unlock_irqrestore(&timers[nodeid].lock, irqflags); return 0; } if (timers[nodeid].next == n) { timers[nodeid].next = rb_next(n); r = 1; } rb_erase(n, &timers[nodeid].timer_head); kfree(t); if (r) { mmtimer_disable_int(cnodeid_to_nasid(nodeid), COMPARATOR); mmtimer_set_next_timer(nodeid); } } spin_unlock_irqrestore(&timers[nodeid].lock, irqflags); return 0; } /* Assumption: it_lock is already held with irq's disabled */ static void sgi_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting) { if (timr->it.mmtimer.clock == TIMER_OFF) { cur_setting->it_interval.tv_nsec = 0; cur_setting->it_interval.tv_sec = 0; cur_setting->it_value.tv_nsec = 0; cur_setting->it_value.tv_sec =0; return; } cur_setting->it_interval = ns_to_timespec(timr->it.mmtimer.incr * sgi_clock_period); cur_setting->it_value = ns_to_timespec((timr->it.mmtimer.expires - rtc_time()) * sgi_clock_period); } static int sgi_timer_set(struct k_itimer *timr, int flags, struct itimerspec * new_setting, struct itimerspec * old_setting) { unsigned long when, period, irqflags; int err = 0; cnodeid_t nodeid; struct mmtimer *base; struct rb_node *n; if (old_setting) sgi_timer_get(timr, old_setting); sgi_timer_del(timr); when = timespec_to_ns(&new_setting->it_value); period = timespec_to_ns(&new_setting->it_interval); if (when == 0) /* Clear timer */ return 0; base = kmalloc(sizeof(struct mmtimer), GFP_KERNEL); if (base == NULL) return -ENOMEM; if (flags & TIMER_ABSTIME) { struct timespec n; unsigned long now; getnstimeofday(&n); now = timespec_to_ns(&n); if (when > now) when -= now; else /* Fire the timer immediately */ when = 0; } /* * Convert to sgi clock period. Need to keep rtc_time() as near as possible * to getnstimeofday() in order to be as faithful as possible to the time * specified. */ when = (when + sgi_clock_period - 1) / sgi_clock_period + rtc_time(); period = (period + sgi_clock_period - 1) / sgi_clock_period; /* * We are allocating a local SHub comparator. If we would be moved to another * cpu then another SHub may be local to us. Prohibit that by switching off * preemption. */ preempt_disable(); nodeid = cpu_to_node(smp_processor_id()); /* Lock the node timer structure */ spin_lock_irqsave(&timers[nodeid].lock, irqflags); base->timer = timr; base->cpu = smp_processor_id(); timr->it.mmtimer.clock = TIMER_SET; timr->it.mmtimer.node = nodeid; timr->it.mmtimer.incr = period; timr->it.mmtimer.expires = when; n = timers[nodeid].next; /* Add the new struct mmtimer to node's timer list */ mmtimer_add_list(base); if (timers[nodeid].next == n) { /* No need to reprogram comparator for now */ spin_unlock_irqrestore(&timers[nodeid].lock, irqflags); preempt_enable(); return err; } /* We need to reprogram the comparator */ if (n) mmtimer_disable_int(cnodeid_to_nasid(nodeid), COMPARATOR); mmtimer_set_next_timer(nodeid); /* Unlock the node timer structure */ spin_unlock_irqrestore(&timers[nodeid].lock, irqflags); preempt_enable(); return err; } static struct k_clock sgi_clock = { .res = 0, .clock_set = sgi_clock_set, .clock_get = sgi_clock_get, .timer_create = sgi_timer_create, .nsleep = do_posix_clock_nonanosleep, .timer_set = sgi_timer_set, .timer_del = sgi_timer_del, .timer_get = sgi_timer_get }; /** * mmtimer_init - device initialization routine * * Does initial setup for the mmtimer device. */ static int __init mmtimer_init(void) { cnodeid_t node, maxn = -1; if (!ia64_platform_is("sn2")) return 0; /* * Sanity check the cycles/sec variable */ if (sn_rtc_cycles_per_second < 100000) { printk(KERN_ERR "%s: unable to determine clock frequency\n", MMTIMER_NAME); goto out1; } mmtimer_femtoperiod = ((unsigned long)1E15 + sn_rtc_cycles_per_second / 2) / sn_rtc_cycles_per_second; if (request_irq(SGI_MMTIMER_VECTOR, mmtimer_interrupt, IRQF_PERCPU, MMTIMER_NAME, NULL)) { printk(KERN_WARNING "%s: unable to allocate interrupt.", MMTIMER_NAME); goto out1; } if (misc_register(&mmtimer_miscdev)) { printk(KERN_ERR "%s: failed to register device\n", MMTIMER_NAME); goto out2; } /* Get max numbered node, calculate slots needed */ for_each_online_node(node) { maxn = node; } maxn++; /* Allocate list of node ptrs to mmtimer_t's */ timers = kzalloc(sizeof(struct mmtimer_node)*maxn, GFP_KERNEL); if (timers == NULL) { printk(KERN_ERR "%s: failed to allocate memory for device\n", MMTIMER_NAME); goto out3; } /* Initialize struct mmtimer's for each online node */ for_each_online_node(node) { spin_lock_init(&timers[node].lock); tasklet_init(&timers[node].tasklet, mmtimer_tasklet, (unsigned long) node); } sgi_clock_period = sgi_clock.res = NSEC_PER_SEC / sn_rtc_cycles_per_second; register_posix_clock(CLOCK_SGI_CYCLE, &sgi_clock); printk(KERN_INFO "%s: v%s, %ld MHz\n", MMTIMER_DESC, MMTIMER_VERSION, sn_rtc_cycles_per_second/(unsigned long)1E6); return 0; out3: kfree(timers); misc_deregister(&mmtimer_miscdev); out2: free_irq(SGI_MMTIMER_VECTOR, NULL); out1: return -1; } module_init(mmtimer_init);