kernel/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) 2009-2013 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         = 299,
  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         raw_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 if (is_uvx_hub())
 106                 return uv_read_global_mmr64(pnode, UVXH_EVENT_OCCURRED2) &
 107                         UVXH_EVENT_OCCURRED2_RTC_1_MASK;
 108         return 0;
 109 }
 110
 111 /* Setup interrupt and return non-zero if early expiration occurred. */
 112 static int uv_setup_intr(int cpu, u64 expires)
 113 {
 114         u64 val;
 115         unsigned long apicid = cpu_physical_id(cpu) | uv_apicid_hibits;
 116         int pnode = uv_cpu_to_pnode(cpu);
 117
 118         uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG,
 119                 UVH_RTC1_INT_CONFIG_M_MASK);
 120         uv_write_global_mmr64(pnode, UVH_INT_CMPB, -1L);
 121
 122         if (is_uv1_hub())
 123                 uv_write_global_mmr64(pnode, UVH_EVENT_OCCURRED0_ALIAS,
 124                                 UV1H_EVENT_OCCURRED0_RTC1_MASK);
 125         else
 126                 uv_write_global_mmr64(pnode, UVXH_EVENT_OCCURRED2_ALIAS,
 127                                 UVXH_EVENT_OCCURRED2_RTC_1_MASK);
 128
 129         val = (X86_PLATFORM_IPI_VECTOR << UVH_RTC1_INT_CONFIG_VECTOR_SHFT) |
 130                 ((u64)apicid << UVH_RTC1_INT_CONFIG_APIC_ID_SHFT);
 131
 132         /* Set configuration */
 133         uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG, val);
 134         /* Initialize comparator value */
 135         uv_write_global_mmr64(pnode, UVH_INT_CMPB, expires);
 136
 137         if (uv_read_rtc(NULL) <= expires)
 138                 return 0;
 139
 140         return !uv_intr_pending(pnode);
 141 }
 142
 143 /*
 144  * Per-cpu timer tracking routines
 145  */
 146
 147 static __init void uv_rtc_deallocate_timers(void)
 148 {
 149         int bid;
 150
 151         for_each_possible_blade(bid) {
 152                 kfree(blade_info[bid]);
 153         }
 154         kfree(blade_info);
 155 }
 156
 157 /* Allocate per-node list of cpu timer expiration times. */
 158 static __init int uv_rtc_allocate_timers(void)
 159 {
 160         int cpu;
 161
 162         blade_info = kzalloc(uv_possible_blades * sizeof(void *), GFP_KERNEL);
 163         if (!blade_info)
 164                 return -ENOMEM;
 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                         raw_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         raw_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                         raw_spin_unlock_irqrestore(&head->lock, flags);
 248                         return -ETIME;
 249                 }
 250         }
 251
 252         raw_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         raw_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         raw_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         cycle_t cycles;
 304
 305         preempt_disable();
 306         if (uv_get_min_hub_revision_id() == 1)
 307                 offset = 0;
 308         else
 309                 offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE;
 310
 311         cycles = (cycle_t)uv_read_local_mmr(UVH_RTC | offset);
 312         preempt_enable();
 313
 314         return cycles;
 315 }
 316
 317 /*
 318  * Program the next event, relative to now
 319  */
 320 static int uv_rtc_next_event(unsigned long delta,
 321                              struct clock_event_device *ced)
 322 {
 323         int ced_cpu = cpumask_first(ced->cpumask);
 324
 325         return uv_rtc_set_timer(ced_cpu, delta + uv_read_rtc(NULL));
 326 }
 327
 328 /*
 329  * Setup the RTC timer in oneshot mode
 330  */
 331 static void uv_rtc_timer_setup(enum clock_event_mode mode,
 332                                struct clock_event_device *evt)
 333 {
 334         int ced_cpu = cpumask_first(evt->cpumask);
 335
 336         switch (mode) {
 337         case CLOCK_EVT_MODE_PERIODIC:
 338         case CLOCK_EVT_MODE_ONESHOT:
 339         case CLOCK_EVT_MODE_RESUME:
 340                 /* Nothing to do here yet */
 341                 break;
 342         case CLOCK_EVT_MODE_UNUSED:
 343         case CLOCK_EVT_MODE_SHUTDOWN:
 344                 uv_rtc_unset_timer(ced_cpu, 1);
 345                 break;
 346         }
 347 }
 348
 349 static void uv_rtc_interrupt(void)
 350 {
 351         int cpu = smp_processor_id();
 352         struct clock_event_device *ced = &per_cpu(cpu_ced, cpu);
 353
 354         if (!ced || !ced->event_handler)
 355                 return;
 356
 357         if (uv_rtc_unset_timer(cpu, 0) != 1)
 358                 return;
 359
 360         ced->event_handler(ced);
 361 }
 362
 363 static int __init uv_enable_evt_rtc(char *str)
 364 {
 365         uv_rtc_evt_enable = 1;
 366
 367         return 1;
 368 }
 369 __setup("uvrtcevt", uv_enable_evt_rtc);
 370
 371 static __init void uv_rtc_register_clockevents(struct work_struct *dummy)
 372 {
 373         struct clock_event_device *ced = this_cpu_ptr(&cpu_ced);
 374
 375         *ced = clock_event_device_uv;
 376         ced->cpumask = cpumask_of(smp_processor_id());
 377         clockevents_register_device(ced);
 378 }
 379
 380 static __init int uv_rtc_setup_clock(void)
 381 {
 382         int rc;
 383
 384         if (!is_uv_system())
 385                 return -ENODEV;
 386
 387         rc = clocksource_register_hz(&clocksource_uv, sn_rtc_cycles_per_second);
 388         if (rc)
 389                 printk(KERN_INFO "UV RTC clocksource failed rc %d\n", rc);
 390         else
 391                 printk(KERN_INFO "UV RTC clocksource registered freq %lu MHz\n",
 392                         sn_rtc_cycles_per_second/(unsigned long)1E6);
 393
 394         if (rc || !uv_rtc_evt_enable || x86_platform_ipi_callback)
 395                 return rc;
 396
 397         /* Setup and register clockevents */
 398         rc = uv_rtc_allocate_timers();
 399         if (rc)
 400                 goto error;
 401
 402         x86_platform_ipi_callback = uv_rtc_interrupt;
 403
 404         clock_event_device_uv.mult = div_sc(sn_rtc_cycles_per_second,
 405                                 NSEC_PER_SEC, clock_event_device_uv.shift);
 406
 407         clock_event_device_uv.min_delta_ns = NSEC_PER_SEC /
 408                                                 sn_rtc_cycles_per_second;
 409
 410         clock_event_device_uv.max_delta_ns = clocksource_uv.mask *
 411                                 (NSEC_PER_SEC / sn_rtc_cycles_per_second);
 412
 413         rc = schedule_on_each_cpu(uv_rtc_register_clockevents);
 414         if (rc) {
 415                 x86_platform_ipi_callback = NULL;
 416                 uv_rtc_deallocate_timers();
 417                 goto error;
 418         }
 419
 420         printk(KERN_INFO "UV RTC clockevents registered\n");
 421
 422         return 0;
 423
 424 error:
 425         clocksource_unregister(&clocksource_uv);
 426         printk(KERN_INFO "UV RTC clockevents failed rc %d\n", rc);
 427
 428         return rc;
 429 }
 430 arch_initcall(uv_rtc_setup_clock);