arch/x86/platform/uv/uv_time.c

   1 /*
   2  * SGI RTC clock/timer routines.
   3  *
   4  *  This program is free software; you can redistribute it and/or modify
   5  *  it under the terms of the GNU General Public License as published by
   6  *  the Free Software Foundation; either version 2 of the License, or
   7  *  (at your option) any later version.
   8  *
   9  *  This program is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *  GNU General Public License for more details.
  13  *
  14  *  You should have received a copy of the GNU General Public License
  15  *  along with this program; if not, write to the Free Software
  16  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  17  *
  18  *  Copyright (c) 2009 Silicon Graphics, Inc.  All Rights Reserved.
  19  *  Copyright (c) Dimitri Sivanich
  20  */
  21 #include <linux/clockchips.h>
  22 #include <linux/slab.h>
  23
  24 #include <asm/uv/uv_mmrs.h>
  25 #include <asm/uv/uv_hub.h>
  26 #include <asm/uv/bios.h>
  27 #include <asm/uv/uv.h>
  28 #include <asm/apic.h>
  29 #include <asm/cpu.h>
  30
  31 #define RTC_NAME                "sgi_rtc"
  32
  33 static cycle_t uv_read_rtc(struct clocksource *cs);
  34 static int uv_rtc_next_event(unsigned long, struct clock_event_device *);
  35 static void uv_rtc_timer_setup(enum clock_event_mode,
  36                                 struct clock_event_device *);
  37
  38 static struct clocksource clocksource_uv = {
  39         .name           = RTC_NAME,
  40         .rating         = 400,
  41         .read           = uv_read_rtc,
  42         .mask           = (cycle_t)UVH_RTC_REAL_TIME_CLOCK_MASK,
  43         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  44 };
  45
  46 static struct clock_event_device clock_event_device_uv = {
  47         .name           = RTC_NAME,
  48         .features       = CLOCK_EVT_FEAT_ONESHOT,
  49         .shift          = 20,
  50         .rating         = 400,
  51         .irq            = -1,
  52         .set_next_event = uv_rtc_next_event,
  53         .set_mode       = uv_rtc_timer_setup,
  54         .event_handler  = NULL,
  55 };
  56
  57 static DEFINE_PER_CPU(struct clock_event_device, cpu_ced);
  58
  59 /* There is one of these allocated per node */
  60 struct uv_rtc_timer_head {
  61         spinlock_t      lock;
  62         /* next cpu waiting for timer, local node relative: */
  63         int             next_cpu;
  64         /* number of cpus on this node: */
  65         int             ncpus;
  66         struct {
  67                 int     lcpu;           /* systemwide logical cpu number */
  68                 u64     expires;        /* next timer expiration for this cpu */
  69         } cpu[1];
  70 };
  71
  72 /*
  73  * Access to uv_rtc_timer_head via blade id.
  74  */
  75 static struct uv_rtc_timer_head         **blade_info __read_mostly;
  76
  77 static int                              uv_rtc_evt_enable;
  78
  79 /*
  80  * Hardware interface routines
  81  */
  82
  83 /* Send IPIs to another node */
  84 static void uv_rtc_send_IPI(int cpu)
  85 {
  86         unsigned long apicid, val;
  87         int pnode;
  88
  89         apicid = cpu_physical_id(cpu);
  90         pnode = uv_apicid_to_pnode(apicid);
  91         apicid |= uv_apicid_hibits;
  92         val = (1UL << UVH_IPI_INT_SEND_SHFT) |
  93               (apicid << UVH_IPI_INT_APIC_ID_SHFT) |
  94               (X86_PLATFORM_IPI_VECTOR << UVH_IPI_INT_VECTOR_SHFT);
  95
  96         uv_write_global_mmr64(pnode, UVH_IPI_INT, val);
  97 }
  98
  99 /* Check for an RTC interrupt pending */
 100 static int uv_intr_pending(int pnode)
 101 {
 102         if (is_uv1_hub())
 103                 return uv_read_global_mmr64(pnode, UVH_EVENT_OCCURRED0) &
 104                         UV1H_EVENT_OCCURRED0_RTC1_MASK;
 105         else
 106                 return uv_read_global_mmr64(pnode, UV2H_EVENT_OCCURRED2) &
 107                         UV2H_EVENT_OCCURRED2_RTC_1_MASK;
 108 }
 109
 110 /* Setup interrupt and return non-zero if early expiration occurred. */
 111 static int uv_setup_intr(int cpu, u64 expires)
 112 {
 113         u64 val;
 114         unsigned long apicid = cpu_physical_id(cpu) | uv_apicid_hibits;
 115         int pnode = uv_cpu_to_pnode(cpu);
 116
 117         uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG,
 118                 UVH_RTC1_INT_CONFIG_M_MASK);
 119         uv_write_global_mmr64(pnode, UVH_INT_CMPB, -1L);
 120
 121         if (is_uv1_hub())
 122                 uv_write_global_mmr64(pnode, UVH_EVENT_OCCURRED0_ALIAS,
 123                                 UV1H_EVENT_OCCURRED0_RTC1_MASK);
 124         else
 125                 uv_write_global_mmr64(pnode, UV2H_EVENT_OCCURRED2_ALIAS,
 126                                 UV2H_EVENT_OCCURRED2_RTC_1_MASK);
 127
 128         val = (X86_PLATFORM_IPI_VECTOR << UVH_RTC1_INT_CONFIG_VECTOR_SHFT) |
 129                 ((u64)apicid << UVH_RTC1_INT_CONFIG_APIC_ID_SHFT);
 130
 131         /* Set configuration */
 132         uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG, val);
 133         /* Initialize comparator value */
 134         uv_write_global_mmr64(pnode, UVH_INT_CMPB, expires);
 135
 136         if (uv_read_rtc(NULL) <= expires)
 137                 return 0;
 138
 139         return !uv_intr_pending(pnode);
 140 }
 141
 142 /*
 143  * Per-cpu timer tracking routines
 144  */
 145
 146 static __init void uv_rtc_deallocate_timers(void)
 147 {
 148         int bid;
 149
 150         for_each_possible_blade(bid) {
 151                 kfree(blade_info[bid]);
 152         }
 153         kfree(blade_info);
 154 }
 155
 156 /* Allocate per-node list of cpu timer expiration times. */
 157 static __init int uv_rtc_allocate_timers(void)
 158 {
 159         int cpu;
 160
 161         blade_info = kmalloc(uv_possible_blades * sizeof(void *), GFP_KERNEL);
 162         if (!blade_info)
 163                 return -ENOMEM;
 164         memset(blade_info, 0, uv_possible_blades * sizeof(void *));
 165
 166         for_each_present_cpu(cpu) {
 167                 int nid = cpu_to_node(cpu);
 168                 int bid = uv_cpu_to_blade_id(cpu);
 169                 int bcpu = uv_cpu_hub_info(cpu)->blade_processor_id;
 170                 struct uv_rtc_timer_head *head = blade_info[bid];
 171
 172                 if (!head) {
 173                         head = kmalloc_node(sizeof(struct uv_rtc_timer_head) +
 174                                 (uv_blade_nr_possible_cpus(bid) *
 175                                         2 * sizeof(u64)),
 176                                 GFP_KERNEL, nid);
 177                         if (!head) {
 178                                 uv_rtc_deallocate_timers();
 179                                 return -ENOMEM;
 180                         }
 181                         spin_lock_init(&head->lock);
 182                         head->ncpus = uv_blade_nr_possible_cpus(bid);
 183                         head->next_cpu = -1;
 184                         blade_info[bid] = head;
 185                 }
 186
 187                 head->cpu[bcpu].lcpu = cpu;
 188                 head->cpu[bcpu].expires = ULLONG_MAX;
 189         }
 190
 191         return 0;
 192 }
 193
 194 /* Find and set the next expiring timer.  */
 195 static void uv_rtc_find_next_timer(struct uv_rtc_timer_head *head, int pnode)
 196 {
 197         u64 lowest = ULLONG_MAX;
 198         int c, bcpu = -1;
 199
 200         head->next_cpu = -1;
 201         for (c = 0; c < head->ncpus; c++) {
 202                 u64 exp = head->cpu[c].expires;
 203                 if (exp < lowest) {
 204                         bcpu = c;
 205                         lowest = exp;
 206                 }
 207         }
 208         if (bcpu >= 0) {
 209                 head->next_cpu = bcpu;
 210                 c = head->cpu[bcpu].lcpu;
 211                 if (uv_setup_intr(c, lowest))
 212                         /* If we didn't set it up in time, trigger */
 213                         uv_rtc_send_IPI(c);
 214         } else {
 215                 uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG,
 216                         UVH_RTC1_INT_CONFIG_M_MASK);
 217         }
 218 }
 219
 220 /*
 221  * Set expiration time for current cpu.
 222  *
 223  * Returns 1 if we missed the expiration time.
 224  */
 225 static int uv_rtc_set_timer(int cpu, u64 expires)
 226 {
 227         int pnode = uv_cpu_to_pnode(cpu);
 228         int bid = uv_cpu_to_blade_id(cpu);
 229         struct uv_rtc_timer_head *head = blade_info[bid];
 230         int bcpu = uv_cpu_hub_info(cpu)->blade_processor_id;
 231         u64 *t = &head->cpu[bcpu].expires;
 232         unsigned long flags;
 233         int next_cpu;
 234
 235         spin_lock_irqsave(&head->lock, flags);
 236
 237         next_cpu = head->next_cpu;
 238         *t = expires;
 239
 240         /* Will this one be next to go off? */
 241         if (next_cpu < 0 || bcpu == next_cpu ||
 242                         expires < head->cpu[next_cpu].expires) {
 243                 head->next_cpu = bcpu;
 244                 if (uv_setup_intr(cpu, expires)) {
 245                         *t = ULLONG_MAX;
 246                         uv_rtc_find_next_timer(head, pnode);
 247                         spin_unlock_irqrestore(&head->lock, flags);
 248                         return -ETIME;
 249                 }
 250         }
 251
 252         spin_unlock_irqrestore(&head->lock, flags);
 253         return 0;
 254 }
 255
 256 /*
 257  * Unset expiration time for current cpu.
 258  *
 259  * Returns 1 if this timer was pending.
 260  */
 261 static int uv_rtc_unset_timer(int cpu, int force)
 262 {
 263         int pnode = uv_cpu_to_pnode(cpu);
 264         int bid = uv_cpu_to_blade_id(cpu);
 265         struct uv_rtc_timer_head *head = blade_info[bid];
 266         int bcpu = uv_cpu_hub_info(cpu)->blade_processor_id;
 267         u64 *t = &head->cpu[bcpu].expires;
 268         unsigned long flags;
 269         int rc = 0;
 270
 271         spin_lock_irqsave(&head->lock, flags);
 272
 273         if ((head->next_cpu == bcpu && uv_read_rtc(NULL) >= *t) || force)
 274                 rc = 1;
 275
 276         if (rc) {
 277                 *t = ULLONG_MAX;
 278                 /* Was the hardware setup for this timer? */
 279                 if (head->next_cpu == bcpu)
 280                         uv_rtc_find_next_timer(head, pnode);
 281         }
 282
 283         spin_unlock_irqrestore(&head->lock, flags);
 284
 285         return rc;
 286 }
 287
 288
 289 /*
 290  * Kernel interface routines.
 291  */
 292
 293 /*
 294  * Read the RTC.
 295  *
 296  * Starting with HUB rev 2.0, the UV RTC register is replicated across all
 297  * cachelines of it's own page.  This allows faster simultaneous reads
 298  * from a given socket.
 299  */
 300 static cycle_t uv_read_rtc(struct clocksource *cs)
 301 {
 302         unsigned long offset;
 303
 304         if (uv_get_min_hub_revision_id() == 1)
 305                 offset = 0;
 306         else
 307                 offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE;
 308
 309         return (cycle_t)uv_read_local_mmr(UVH_RTC | offset);
 310 }
 311
 312 /*
 313  * Program the next event, relative to now
 314  */
 315 static int uv_rtc_next_event(unsigned long delta,
 316                              struct clock_event_device *ced)
 317 {
 318         int ced_cpu = cpumask_first(ced->cpumask);
 319
 320         return uv_rtc_set_timer(ced_cpu, delta + uv_read_rtc(NULL));
 321 }
 322
 323 /*
 324  * Setup the RTC timer in oneshot mode
 325  */
 326 static void uv_rtc_timer_setup(enum clock_event_mode mode,
 327                                struct clock_event_device *evt)
 328 {
 329         int ced_cpu = cpumask_first(evt->cpumask);
 330
 331         switch (mode) {
 332         case CLOCK_EVT_MODE_PERIODIC:
 333         case CLOCK_EVT_MODE_ONESHOT:
 334         case CLOCK_EVT_MODE_RESUME:
 335                 /* Nothing to do here yet */
 336                 break;
 337         case CLOCK_EVT_MODE_UNUSED:
 338         case CLOCK_EVT_MODE_SHUTDOWN:
 339                 uv_rtc_unset_timer(ced_cpu, 1);
 340                 break;
 341         }
 342 }
 343
 344 static void uv_rtc_interrupt(void)
 345 {
 346         int cpu = smp_processor_id();
 347         struct clock_event_device *ced = &per_cpu(cpu_ced, cpu);
 348
 349         if (!ced || !ced->event_handler)
 350                 return;
 351
 352         if (uv_rtc_unset_timer(cpu, 0) != 1)
 353                 return;
 354
 355         ced->event_handler(ced);
 356 }
 357
 358 static int __init uv_enable_evt_rtc(char *str)
 359 {
 360         uv_rtc_evt_enable = 1;
 361
 362         return 1;
 363 }
 364 __setup("uvrtcevt", uv_enable_evt_rtc);
 365
 366 static __init void uv_rtc_register_clockevents(struct work_struct *dummy)
 367 {
 368         struct clock_event_device *ced = &__get_cpu_var(cpu_ced);
 369
 370         *ced = clock_event_device_uv;
 371         ced->cpumask = cpumask_of(smp_processor_id());
 372         clockevents_register_device(ced);
 373 }
 374
 375 static __init int uv_rtc_setup_clock(void)
 376 {
 377         int rc;
 378
 379         if (!is_uv_system())
 380                 return -ENODEV;
 381
 382         /* If single blade, prefer tsc */
 383         if (uv_num_possible_blades() == 1)
 384                 clocksource_uv.rating = 250;
 385
 386         rc = clocksource_register_hz(&clocksource_uv, sn_rtc_cycles_per_second);
 387         if (rc)
 388                 printk(KERN_INFO "UV RTC clocksource failed rc %d\n", rc);
 389         else
 390                 printk(KERN_INFO "UV RTC clocksource registered freq %lu MHz\n",
 391                         sn_rtc_cycles_per_second/(unsigned long)1E6);
 392
 393         if (rc || !uv_rtc_evt_enable || x86_platform_ipi_callback)
 394                 return rc;
 395
 396         /* Setup and register clockevents */
 397         rc = uv_rtc_allocate_timers();
 398         if (rc)
 399                 goto error;
 400
 401         x86_platform_ipi_callback = uv_rtc_interrupt;
 402
 403         clock_event_device_uv.mult = div_sc(sn_rtc_cycles_per_second,
 404                                 NSEC_PER_SEC, clock_event_device_uv.shift);
 405
 406         clock_event_device_uv.min_delta_ns = NSEC_PER_SEC /
 407                                                 sn_rtc_cycles_per_second;
 408
 409         clock_event_device_uv.max_delta_ns = clocksource_uv.mask *
 410                                 (NSEC_PER_SEC / sn_rtc_cycles_per_second);
 411
 412         rc = schedule_on_each_cpu(uv_rtc_register_clockevents);
 413         if (rc) {
 414                 x86_platform_ipi_callback = NULL;
 415                 uv_rtc_deallocate_timers();
 416                 goto error;
 417         }
 418
 419         printk(KERN_INFO "UV RTC clockevents registered\n");
 420
 421         return 0;
 422
 423 error:
 424         clocksource_unregister(&clocksource_uv);
 425         printk(KERN_INFO "UV RTC clockevents failed rc %d\n", rc);
 426
 427         return rc;
 428 }
 429 arch_initcall(uv_rtc_setup_clock);