2 * Timer device implementation for SGI SN platforms.
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
8 * Copyright (c) 2001-2006 Silicon Graphics, Inc. All rights reserved.
10 * This driver exports an API that should be supportable by any HPET or IA-PC
11 * multimedia timer. The code below is currently specific to the SGI Altix
14 * 11/01/01 - jbarnes - initial revision
15 * 9/10/04 - Christoph Lameter - remove interrupt support for kernel inclusion
16 * 10/1/04 - Christoph Lameter - provide posix clock CLOCK_SGI_CYCLE
17 * 10/13/04 - Christoph Lameter, Dimitri Sivanich - provide timer interrupt
18 * support via the posix timer interface
21 #include <linux/types.h>
22 #include <linux/kernel.h>
23 #include <linux/ioctl.h>
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/errno.h>
28 #include <linux/mmtimer.h>
29 #include <linux/miscdevice.h>
30 #include <linux/posix-timers.h>
31 #include <linux/interrupt.h>
33 #include <asm/uaccess.h>
34 #include <asm/sn/addrs.h>
35 #include <asm/sn/intr.h>
36 #include <asm/sn/shub_mmr.h>
37 #include <asm/sn/nodepda.h>
38 #include <asm/sn/shubio.h>
40 MODULE_AUTHOR("Jesse Barnes <jbarnes@sgi.com>");
41 MODULE_DESCRIPTION("SGI Altix RTC Timer");
42 MODULE_LICENSE("GPL");
44 /* name of the device, usually in /dev */
45 #define MMTIMER_NAME "mmtimer"
46 #define MMTIMER_DESC "SGI Altix RTC Timer"
47 #define MMTIMER_VERSION "2.1"
49 #define RTC_BITS 55 /* 55 bits for this implementation */
51 extern unsigned long sn_rtc_cycles_per_second
;
53 #define RTC_COUNTER_ADDR ((long *)LOCAL_MMR_ADDR(SH_RTC))
55 #define rtc_time() (*RTC_COUNTER_ADDR)
57 static int mmtimer_ioctl(struct inode
*inode
, struct file
*file
,
58 unsigned int cmd
, unsigned long arg
);
59 static int mmtimer_mmap(struct file
*file
, struct vm_area_struct
*vma
);
62 * Period in femtoseconds (10^-15 s)
64 static unsigned long mmtimer_femtoperiod
= 0;
66 static const struct file_operations mmtimer_fops
= {
69 .ioctl
= mmtimer_ioctl
,
73 * We only have comparison registers RTC1-4 currently available per
74 * node. RTC0 is used by SAL.
76 #define NUM_COMPARATORS 3
77 /* Check for an RTC interrupt pending */
78 static int inline mmtimer_int_pending(int comparator
)
80 if (HUB_L((unsigned long *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED
)) &
81 SH_EVENT_OCCURRED_RTC1_INT_MASK
<< comparator
)
86 /* Clear the RTC interrupt pending bit */
87 static void inline mmtimer_clr_int_pending(int comparator
)
89 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED_ALIAS
),
90 SH_EVENT_OCCURRED_RTC1_INT_MASK
<< comparator
);
93 /* Setup timer on comparator RTC1 */
94 static void inline mmtimer_setup_int_0(u64 expires
)
98 /* Disable interrupt */
99 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE
), 0UL);
101 /* Initialize comparator value */
102 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_INT_CMPB
), -1L);
104 /* Clear pending bit */
105 mmtimer_clr_int_pending(0);
107 val
= ((u64
)SGI_MMTIMER_VECTOR
<< SH_RTC1_INT_CONFIG_IDX_SHFT
) |
108 ((u64
)cpu_physical_id(smp_processor_id()) <<
109 SH_RTC1_INT_CONFIG_PID_SHFT
);
111 /* Set configuration */
112 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC1_INT_CONFIG
), val
);
114 /* Enable RTC interrupts */
115 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE
), 1UL);
117 /* Initialize comparator value */
118 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_INT_CMPB
), expires
);
123 /* Setup timer on comparator RTC2 */
124 static void inline mmtimer_setup_int_1(u64 expires
)
128 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE
), 0UL);
130 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_INT_CMPC
), -1L);
132 mmtimer_clr_int_pending(1);
134 val
= ((u64
)SGI_MMTIMER_VECTOR
<< SH_RTC2_INT_CONFIG_IDX_SHFT
) |
135 ((u64
)cpu_physical_id(smp_processor_id()) <<
136 SH_RTC2_INT_CONFIG_PID_SHFT
);
138 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC2_INT_CONFIG
), val
);
140 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE
), 1UL);
142 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_INT_CMPC
), expires
);
145 /* Setup timer on comparator RTC3 */
146 static void inline mmtimer_setup_int_2(u64 expires
)
150 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE
), 0UL);
152 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_INT_CMPD
), -1L);
154 mmtimer_clr_int_pending(2);
156 val
= ((u64
)SGI_MMTIMER_VECTOR
<< SH_RTC3_INT_CONFIG_IDX_SHFT
) |
157 ((u64
)cpu_physical_id(smp_processor_id()) <<
158 SH_RTC3_INT_CONFIG_PID_SHFT
);
160 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC3_INT_CONFIG
), val
);
162 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE
), 1UL);
164 HUB_S((u64
*)LOCAL_MMR_ADDR(SH_INT_CMPD
), expires
);
168 * This function must be called with interrupts disabled and preemption off
169 * in order to insure that the setup succeeds in a deterministic time frame.
170 * It will check if the interrupt setup succeeded.
172 static int inline mmtimer_setup(int comparator
, unsigned long expires
)
175 switch (comparator
) {
177 mmtimer_setup_int_0(expires
);
180 mmtimer_setup_int_1(expires
);
183 mmtimer_setup_int_2(expires
);
186 /* We might've missed our expiration time */
187 if (rtc_time() < expires
)
191 * If an interrupt is already pending then its okay
192 * if not then we failed
194 return mmtimer_int_pending(comparator
);
197 static int inline mmtimer_disable_int(long nasid
, int comparator
)
199 switch (comparator
) {
201 nasid
== -1 ? HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE
),
202 0UL) : REMOTE_HUB_S(nasid
, SH_RTC1_INT_ENABLE
, 0UL);
205 nasid
== -1 ? HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE
),
206 0UL) : REMOTE_HUB_S(nasid
, SH_RTC2_INT_ENABLE
, 0UL);
209 nasid
== -1 ? HUB_S((u64
*)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE
),
210 0UL) : REMOTE_HUB_S(nasid
, SH_RTC3_INT_ENABLE
, 0UL);
218 #define TIMER_OFF 0xbadcabLL
220 /* There is one of these for each comparator */
221 typedef struct mmtimer
{
222 spinlock_t lock ____cacheline_aligned
;
223 struct k_itimer
*timer
;
226 struct tasklet_struct tasklet
;
229 static mmtimer_t
** timers
;
232 * mmtimer_ioctl - ioctl interface for /dev/mmtimer
233 * @inode: inode of the device
234 * @file: file structure for the device
235 * @cmd: command to execute
236 * @arg: optional argument to command
238 * Executes the command specified by @cmd. Returns 0 for success, < 0 for
243 * %MMTIMER_GETOFFSET - Should return the offset (relative to the start
244 * of the page where the registers are mapped) for the counter in question.
246 * %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15)
249 * %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address
252 * %MMTIMER_GETBITS - Returns the number of bits in the clock's counter
254 * %MMTIMER_MMAPAVAIL - Returns 1 if the registers can be mmap'd into userspace
256 * %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it
257 * in the address specified by @arg.
259 static int mmtimer_ioctl(struct inode
*inode
, struct file
*file
,
260 unsigned int cmd
, unsigned long arg
)
265 case MMTIMER_GETOFFSET
: /* offset of the counter */
267 * SN RTC registers are on their own 64k page
269 if(PAGE_SIZE
<= (1 << 16))
270 ret
= (((long)RTC_COUNTER_ADDR
) & (PAGE_SIZE
-1)) / 8;
275 case MMTIMER_GETRES
: /* resolution of the clock in 10^-15 s */
276 if(copy_to_user((unsigned long __user
*)arg
,
277 &mmtimer_femtoperiod
, sizeof(unsigned long)))
281 case MMTIMER_GETFREQ
: /* frequency in Hz */
282 if(copy_to_user((unsigned long __user
*)arg
,
283 &sn_rtc_cycles_per_second
,
284 sizeof(unsigned long)))
289 case MMTIMER_GETBITS
: /* number of bits in the clock */
293 case MMTIMER_MMAPAVAIL
: /* can we mmap the clock into userspace? */
294 ret
= (PAGE_SIZE
<= (1 << 16)) ? 1 : 0;
297 case MMTIMER_GETCOUNTER
:
298 if(copy_to_user((unsigned long __user
*)arg
,
299 RTC_COUNTER_ADDR
, sizeof(unsigned long)))
311 * mmtimer_mmap - maps the clock's registers into userspace
312 * @file: file structure for the device
313 * @vma: VMA to map the registers into
315 * Calls remap_pfn_range() to map the clock's registers into
316 * the calling process' address space.
318 static int mmtimer_mmap(struct file
*file
, struct vm_area_struct
*vma
)
320 unsigned long mmtimer_addr
;
322 if (vma
->vm_end
- vma
->vm_start
!= PAGE_SIZE
)
325 if (vma
->vm_flags
& VM_WRITE
)
328 if (PAGE_SIZE
> (1 << 16))
331 vma
->vm_page_prot
= pgprot_noncached(vma
->vm_page_prot
);
333 mmtimer_addr
= __pa(RTC_COUNTER_ADDR
);
334 mmtimer_addr
&= ~(PAGE_SIZE
- 1);
335 mmtimer_addr
&= 0xfffffffffffffffUL
;
337 if (remap_pfn_range(vma
, vma
->vm_start
, mmtimer_addr
>> PAGE_SHIFT
,
338 PAGE_SIZE
, vma
->vm_page_prot
)) {
339 printk(KERN_ERR
"remap_pfn_range failed in mmtimer.c\n");
346 static struct miscdevice mmtimer_miscdev
= {
352 static struct timespec sgi_clock_offset
;
353 static int sgi_clock_period
;
356 * Posix Timer Interface
359 static struct timespec sgi_clock_offset
;
360 static int sgi_clock_period
;
362 static int sgi_clock_get(clockid_t clockid
, struct timespec
*tp
)
366 nsec
= rtc_time() * sgi_clock_period
367 + sgi_clock_offset
.tv_nsec
;
368 tp
->tv_sec
= div_long_long_rem(nsec
, NSEC_PER_SEC
, &tp
->tv_nsec
)
369 + sgi_clock_offset
.tv_sec
;
373 static int sgi_clock_set(clockid_t clockid
, struct timespec
*tp
)
379 nsec
= rtc_time() * sgi_clock_period
;
381 sgi_clock_offset
.tv_sec
= tp
->tv_sec
- div_long_long_rem(nsec
, NSEC_PER_SEC
, &rem
);
383 if (rem
<= tp
->tv_nsec
)
384 sgi_clock_offset
.tv_nsec
= tp
->tv_sec
- rem
;
386 sgi_clock_offset
.tv_nsec
= tp
->tv_sec
+ NSEC_PER_SEC
- rem
;
387 sgi_clock_offset
.tv_sec
--;
393 * Schedule the next periodic interrupt. This function will attempt
394 * to schedule a periodic interrupt later if necessary. If the scheduling
395 * of an interrupt fails then the time to skip is lengthened
396 * exponentially in order to ensure that the next interrupt
397 * can be properly scheduled..
399 static int inline reschedule_periodic_timer(mmtimer_t
*x
)
402 struct k_itimer
*t
= x
->timer
;
404 t
->it
.mmtimer
.clock
= x
->i
;
410 t
->it
.mmtimer
.expires
+= t
->it
.mmtimer
.incr
<< n
;
411 t
->it_overrun
+= 1 << n
;
416 } while (!mmtimer_setup(x
->i
, t
->it
.mmtimer
.expires
));
422 * mmtimer_interrupt - timer interrupt handler
424 * @dev_id: device the irq came from
426 * Called when one of the comarators matches the counter, This
427 * routine will send signals to processes that have requested
430 * This interrupt is run in an interrupt context
431 * by the SHUB. It is therefore safe to locally access SHub
435 mmtimer_interrupt(int irq
, void *dev_id
)
438 unsigned long expires
= 0;
439 int result
= IRQ_NONE
;
440 unsigned indx
= cpu_to_node(smp_processor_id());
443 * Do this once for each comparison register
445 for (i
= 0; i
< NUM_COMPARATORS
; i
++) {
446 mmtimer_t
*base
= timers
[indx
] + i
;
447 /* Make sure this doesn't get reused before tasklet_sched */
448 spin_lock(&base
->lock
);
449 if (base
->cpu
== smp_processor_id()) {
451 expires
= base
->timer
->it
.mmtimer
.expires
;
452 /* expires test won't work with shared irqs */
453 if ((mmtimer_int_pending(i
) > 0) ||
454 (expires
&& (expires
< rtc_time()))) {
455 mmtimer_clr_int_pending(i
);
456 tasklet_schedule(&base
->tasklet
);
457 result
= IRQ_HANDLED
;
460 spin_unlock(&base
->lock
);
466 void mmtimer_tasklet(unsigned long data
) {
467 mmtimer_t
*x
= (mmtimer_t
*)data
;
468 struct k_itimer
*t
= x
->timer
;
474 /* Send signal and deal with periodic signals */
475 spin_lock_irqsave(&t
->it_lock
, flags
);
477 /* If timer was deleted between interrupt and here, leave */
482 if (posix_timer_event(t
, 0) != 0) {
484 // printk(KERN_WARNING "mmtimer: cannot deliver signal.\n");
488 if(t
->it
.mmtimer
.incr
) {
490 if (reschedule_periodic_timer(x
)) {
491 printk(KERN_WARNING
"mmtimer: unable to reschedule\n");
495 /* Ensure we don't false trigger in mmtimer_interrupt */
496 t
->it
.mmtimer
.expires
= 0;
498 t
->it_overrun_last
= t
->it_overrun
;
500 spin_unlock(&x
->lock
);
501 spin_unlock_irqrestore(&t
->it_lock
, flags
);
504 static int sgi_timer_create(struct k_itimer
*timer
)
506 /* Insure that a newly created timer is off */
507 timer
->it
.mmtimer
.clock
= TIMER_OFF
;
511 /* This does not really delete a timer. It just insures
512 * that the timer is not active
514 * Assumption: it_lock is already held with irq's disabled
516 static int sgi_timer_del(struct k_itimer
*timr
)
518 int i
= timr
->it
.mmtimer
.clock
;
519 cnodeid_t nodeid
= timr
->it
.mmtimer
.node
;
520 mmtimer_t
*t
= timers
[nodeid
] + i
;
521 unsigned long irqflags
;
523 if (i
!= TIMER_OFF
) {
524 spin_lock_irqsave(&t
->lock
, irqflags
);
525 mmtimer_disable_int(cnodeid_to_nasid(nodeid
),i
);
527 timr
->it
.mmtimer
.clock
= TIMER_OFF
;
528 timr
->it
.mmtimer
.expires
= 0;
529 spin_unlock_irqrestore(&t
->lock
, irqflags
);
534 #define timespec_to_ns(x) ((x).tv_nsec + (x).tv_sec * NSEC_PER_SEC)
535 #define ns_to_timespec(ts, nsec) (ts).tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &(ts).tv_nsec)
537 /* Assumption: it_lock is already held with irq's disabled */
538 static void sgi_timer_get(struct k_itimer
*timr
, struct itimerspec
*cur_setting
)
541 if (timr
->it
.mmtimer
.clock
== TIMER_OFF
) {
542 cur_setting
->it_interval
.tv_nsec
= 0;
543 cur_setting
->it_interval
.tv_sec
= 0;
544 cur_setting
->it_value
.tv_nsec
= 0;
545 cur_setting
->it_value
.tv_sec
=0;
549 ns_to_timespec(cur_setting
->it_interval
, timr
->it
.mmtimer
.incr
* sgi_clock_period
);
550 ns_to_timespec(cur_setting
->it_value
, (timr
->it
.mmtimer
.expires
- rtc_time())* sgi_clock_period
);
555 static int sgi_timer_set(struct k_itimer
*timr
, int flags
,
556 struct itimerspec
* new_setting
,
557 struct itimerspec
* old_setting
)
561 unsigned long when
, period
, irqflags
;
567 sgi_timer_get(timr
, old_setting
);
570 when
= timespec_to_ns(new_setting
->it_value
);
571 period
= timespec_to_ns(new_setting
->it_interval
);
577 if (flags
& TIMER_ABSTIME
) {
582 now
= timespec_to_ns(n
);
586 /* Fire the timer immediately */
591 * Convert to sgi clock period. Need to keep rtc_time() as near as possible
592 * to getnstimeofday() in order to be as faithful as possible to the time
595 when
= (when
+ sgi_clock_period
- 1) / sgi_clock_period
+ rtc_time();
596 period
= (period
+ sgi_clock_period
- 1) / sgi_clock_period
;
599 * We are allocating a local SHub comparator. If we would be moved to another
600 * cpu then another SHub may be local to us. Prohibit that by switching off
605 nodeid
= cpu_to_node(smp_processor_id());
607 /* Don't use an allocated timer, or a deleted one that's pending */
608 for(i
= 0; i
< NUM_COMPARATORS
; i
++) {
609 base
= timers
[nodeid
] + i
;
610 if (!base
->timer
&& !base
->tasklet
.state
) {
615 if (i
== NUM_COMPARATORS
) {
620 spin_lock_irqsave(&base
->lock
, irqflags
);
622 if (base
->timer
|| base
->tasklet
.state
!= 0) {
623 spin_unlock_irqrestore(&base
->lock
, irqflags
);
627 base
->cpu
= smp_processor_id();
629 timr
->it
.mmtimer
.clock
= i
;
630 timr
->it
.mmtimer
.node
= nodeid
;
631 timr
->it
.mmtimer
.incr
= period
;
632 timr
->it
.mmtimer
.expires
= when
;
635 if (!mmtimer_setup(i
, when
)) {
636 mmtimer_disable_int(-1, i
);
637 posix_timer_event(timr
, 0);
638 timr
->it
.mmtimer
.expires
= 0;
641 timr
->it
.mmtimer
.expires
-= period
;
642 if (reschedule_periodic_timer(base
))
646 spin_unlock_irqrestore(&base
->lock
, irqflags
);
653 static struct k_clock sgi_clock
= {
655 .clock_set
= sgi_clock_set
,
656 .clock_get
= sgi_clock_get
,
657 .timer_create
= sgi_timer_create
,
658 .nsleep
= do_posix_clock_nonanosleep
,
659 .timer_set
= sgi_timer_set
,
660 .timer_del
= sgi_timer_del
,
661 .timer_get
= sgi_timer_get
665 * mmtimer_init - device initialization routine
667 * Does initial setup for the mmtimer device.
669 static int __init
mmtimer_init(void)
672 cnodeid_t node
, maxn
= -1;
674 if (!ia64_platform_is("sn2"))
678 * Sanity check the cycles/sec variable
680 if (sn_rtc_cycles_per_second
< 100000) {
681 printk(KERN_ERR
"%s: unable to determine clock frequency\n",
686 mmtimer_femtoperiod
= ((unsigned long)1E15
+ sn_rtc_cycles_per_second
/
687 2) / sn_rtc_cycles_per_second
;
689 if (request_irq(SGI_MMTIMER_VECTOR
, mmtimer_interrupt
, IRQF_PERCPU
, MMTIMER_NAME
, NULL
)) {
690 printk(KERN_WARNING
"%s: unable to allocate interrupt.",
695 if (misc_register(&mmtimer_miscdev
)) {
696 printk(KERN_ERR
"%s: failed to register device\n",
701 /* Get max numbered node, calculate slots needed */
702 for_each_online_node(node
) {
707 /* Allocate list of node ptrs to mmtimer_t's */
708 timers
= kzalloc(sizeof(mmtimer_t
*)*maxn
, GFP_KERNEL
);
709 if (timers
== NULL
) {
710 printk(KERN_ERR
"%s: failed to allocate memory for device\n",
715 /* Allocate mmtimer_t's for each online node */
716 for_each_online_node(node
) {
717 timers
[node
] = kmalloc_node(sizeof(mmtimer_t
)*NUM_COMPARATORS
, GFP_KERNEL
, node
);
718 if (timers
[node
] == NULL
) {
719 printk(KERN_ERR
"%s: failed to allocate memory for device\n",
723 for (i
=0; i
< NUM_COMPARATORS
; i
++) {
724 mmtimer_t
* base
= timers
[node
] + i
;
726 spin_lock_init(&base
->lock
);
730 tasklet_init(&base
->tasklet
, mmtimer_tasklet
,
731 (unsigned long) (base
));
735 sgi_clock_period
= sgi_clock
.res
= NSEC_PER_SEC
/ sn_rtc_cycles_per_second
;
736 register_posix_clock(CLOCK_SGI_CYCLE
, &sgi_clock
);
738 printk(KERN_INFO
"%s: v%s, %ld MHz\n", MMTIMER_DESC
, MMTIMER_VERSION
,
739 sn_rtc_cycles_per_second
/(unsigned long)1E6
);
744 for_each_online_node(node
) {
748 misc_deregister(&mmtimer_miscdev
);
750 free_irq(SGI_MMTIMER_VECTOR
, NULL
);
755 module_init(mmtimer_init
);