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 int uv_rtc_shutdown(struct clock_event_device *evt);
  36
  37 static struct clocksource clocksource_uv = {
  38         .name           = RTC_NAME,
  39         .rating         = 299,
  40         .read           = uv_read_rtc,
  41         .mask           = (cycle_t)UVH_RTC_REAL_TIME_CLOCK_MASK,
  42         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  43 };
  44
  45 static struct clock_event_device clock_event_device_uv = {
  46         .name                   = RTC_NAME,
  47         .features               = CLOCK_EVT_FEAT_ONESHOT,
  48         .shift                  = 20,
  49         .rating                 = 400,
  50         .irq                    = -1,
  51         .set_next_event         = uv_rtc_next_event,
  52         .set_state_shutdown     = uv_rtc_shutdown,
  53         .event_handler          = NULL,
  54 };
  55
  56 static DEFINE_PER_CPU(struct clock_event_device, cpu_ced);
  57
  58 /* There is one of these allocated per node */
  59 struct uv_rtc_timer_head {
  60         spinlock_t      lock;
  61         /* next cpu waiting for timer, local node relative: */
  62         int             next_cpu;
  63         /* number of cpus on this node: */
  64         int             ncpus;
  65         struct {
  66                 int     lcpu;           /* systemwide logical cpu number */
  67                 u64     expires;        /* next timer expiration for this cpu */
  68         } cpu[1];
  69 };
  70
  71 /*
  72  * Access to uv_rtc_timer_head via blade id.
  73  */
  74 static struct uv_rtc_timer_head         **blade_info __read_mostly;
  75
  76 static int                              uv_rtc_evt_enable;
  77
  78 /*
  79  * Hardware interface routines
  80  */
  81
  82 /* Send IPIs to another node */
  83 static void uv_rtc_send_IPI(int cpu)
  84 {
  85         unsigned long apicid, val;
  86         int pnode;
  87
  88         apicid = cpu_physical_id(cpu);
  89         pnode = uv_apicid_to_pnode(apicid);
  90         apicid |= uv_apicid_hibits;
  91         val = (1UL << UVH_IPI_INT_SEND_SHFT) |
  92               (apicid << UVH_IPI_INT_APIC_ID_SHFT) |
  93               (X86_PLATFORM_IPI_VECTOR << UVH_IPI_INT_VECTOR_SHFT);
  94
  95         uv_write_global_mmr64(pnode, UVH_IPI_INT, val);
  96 }
  97
  98 /* Check for an RTC interrupt pending */
  99 static int uv_intr_pending(int pnode)
 100 {
 101         if (is_uv1_hub())
 102                 return uv_read_global_mmr64(pnode, UVH_EVENT_OCCURRED0) &
 103                         UV1H_EVENT_OCCURRED0_RTC1_MASK;
 104         else if (is_uvx_hub())
 105                 return uv_read_global_mmr64(pnode, UVXH_EVENT_OCCURRED2) &
 106                         UVXH_EVENT_OCCURRED2_RTC_1_MASK;
 107         return 0;
 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, UVXH_EVENT_OCCURRED2_ALIAS,
 126                                 UVXH_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 = kzalloc(uv_possible_blades * sizeof(void *), GFP_KERNEL);
 162         if (!blade_info)
 163                 return -ENOMEM;
 164
 165         for_each_present_cpu(cpu) {
 166                 int nid = cpu_to_node(cpu);
 167                 int bid = uv_cpu_to_blade_id(cpu);
 168                 int bcpu = uv_cpu_blade_processor_id(cpu);
 169                 struct uv_rtc_timer_head *head = blade_info[bid];
 170
 171                 if (!head) {
 172                         head = kmalloc_node(sizeof(struct uv_rtc_timer_head) +
 173                                 (uv_blade_nr_possible_cpus(bid) *
 174                                         2 * sizeof(u64)),
 175                                 GFP_KERNEL, nid);
 176                         if (!head) {
 177                                 uv_rtc_deallocate_timers();
 178                                 return -ENOMEM;
 179                         }
 180                         spin_lock_init(&head->lock);
 181                         head->ncpus = uv_blade_nr_possible_cpus(bid);
 182                         head->next_cpu = -1;
 183                         blade_info[bid] = head;
 184                 }
 185
 186                 head->cpu[bcpu].lcpu = cpu;
 187                 head->cpu[bcpu].expires = ULLONG_MAX;
 188         }
 189
 190         return 0;
 191 }
 192
 193 /* Find and set the next expiring timer.  */
 194 static void uv_rtc_find_next_timer(struct uv_rtc_timer_head *head, int pnode)
 195 {
 196         u64 lowest = ULLONG_MAX;
 197         int c, bcpu = -1;
 198
 199         head->next_cpu = -1;
 200         for (c = 0; c < head->ncpus; c++) {
 201                 u64 exp = head->cpu[c].expires;
 202                 if (exp < lowest) {
 203                         bcpu = c;
 204                         lowest = exp;
 205                 }
 206         }
 207         if (bcpu >= 0) {
 208                 head->next_cpu = bcpu;
 209                 c = head->cpu[bcpu].lcpu;
 210                 if (uv_setup_intr(c, lowest))
 211                         /* If we didn't set it up in time, trigger */
 212                         uv_rtc_send_IPI(c);
 213         } else {
 214                 uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG,
 215                         UVH_RTC1_INT_CONFIG_M_MASK);
 216         }
 217 }
 218
 219 /*
 220  * Set expiration time for current cpu.
 221  *
 222  * Returns 1 if we missed the expiration time.
 223  */
 224 static int uv_rtc_set_timer(int cpu, u64 expires)
 225 {
 226         int pnode = uv_cpu_to_pnode(cpu);
 227         int bid = uv_cpu_to_blade_id(cpu);
 228         struct uv_rtc_timer_head *head = blade_info[bid];
 229         int bcpu = uv_cpu_blade_processor_id(cpu);
 230         u64 *t = &head->cpu[bcpu].expires;
 231         unsigned long flags;
 232         int next_cpu;
 233
 234         spin_lock_irqsave(&head->lock, flags);
 235
 236         next_cpu = head->next_cpu;
 237         *t = expires;
 238
 239         /* Will this one be next to go off? */
 240         if (next_cpu < 0 || bcpu == next_cpu ||
 241                         expires < head->cpu[next_cpu].expires) {
 242                 head->next_cpu = bcpu;
 243                 if (uv_setup_intr(cpu, expires)) {
 244                         *t = ULLONG_MAX;
 245                         uv_rtc_find_next_timer(head, pnode);
 246                         spin_unlock_irqrestore(&head->lock, flags);
 247                         return -ETIME;
 248                 }
 249         }
 250
 251         spin_unlock_irqrestore(&head->lock, flags);
 252         return 0;
 253 }
 254
 255 /*
 256  * Unset expiration time for current cpu.
 257  *
 258  * Returns 1 if this timer was pending.
 259  */
 260 static int uv_rtc_unset_timer(int cpu, int force)
 261 {
 262         int pnode = uv_cpu_to_pnode(cpu);
 263         int bid = uv_cpu_to_blade_id(cpu);
 264         struct uv_rtc_timer_head *head = blade_info[bid];
 265         int bcpu = uv_cpu_blade_processor_id(cpu);
 266         u64 *t = &head->cpu[bcpu].expires;
 267         unsigned long flags;
 268         int rc = 0;
 269
 270         spin_lock_irqsave(&head->lock, flags);
 271
 272         if ((head->next_cpu == bcpu && uv_read_rtc(NULL) >= *t) || force)
 273                 rc = 1;
 274
 275         if (rc) {
 276                 *t = ULLONG_MAX;
 277                 /* Was the hardware setup for this timer? */
 278                 if (head->next_cpu == bcpu)
 279                         uv_rtc_find_next_timer(head, pnode);
 280         }
 281
 282         spin_unlock_irqrestore(&head->lock, flags);
 283
 284         return rc;
 285 }
 286
 287
 288 /*
 289  * Kernel interface routines.
 290  */
 291
 292 /*
 293  * Read the RTC.
 294  *
 295  * Starting with HUB rev 2.0, the UV RTC register is replicated across all
 296  * cachelines of it's own page.  This allows faster simultaneous reads
 297  * from a given socket.
 298  */
 299 static cycle_t uv_read_rtc(struct clocksource *cs)
 300 {
 301         unsigned long offset;
 302
 303         if (uv_get_min_hub_revision_id() == 1)
 304                 offset = 0;
 305         else
 306                 offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE;
 307
 308         return (cycle_t)uv_read_local_mmr(UVH_RTC | offset);
 309 }
 310
 311 /*
 312  * Program the next event, relative to now
 313  */
 314 static int uv_rtc_next_event(unsigned long delta,
 315                              struct clock_event_device *ced)
 316 {
 317         int ced_cpu = cpumask_first(ced->cpumask);
 318
 319         return uv_rtc_set_timer(ced_cpu, delta + uv_read_rtc(NULL));
 320 }
 321
 322 /*
 323  * Shutdown the RTC timer
 324  */
 325 static int uv_rtc_shutdown(struct clock_event_device *evt)
 326 {
 327         int ced_cpu = cpumask_first(evt->cpumask);
 328
 329         uv_rtc_unset_timer(ced_cpu, 1);
 330         return 0;
 331 }
 332
 333 static void uv_rtc_interrupt(void)
 334 {
 335         int cpu = smp_processor_id();
 336         struct clock_event_device *ced = &per_cpu(cpu_ced, cpu);
 337
 338         if (!ced || !ced->event_handler)
 339                 return;
 340
 341         if (uv_rtc_unset_timer(cpu, 0) != 1)
 342                 return;
 343
 344         ced->event_handler(ced);
 345 }
 346
 347 static int __init uv_enable_evt_rtc(char *str)
 348 {
 349         uv_rtc_evt_enable = 1;
 350
 351         return 1;
 352 }
 353 __setup("uvrtcevt", uv_enable_evt_rtc);
 354
 355 static __init void uv_rtc_register_clockevents(struct work_struct *dummy)
 356 {
 357         struct clock_event_device *ced = this_cpu_ptr(&cpu_ced);
 358
 359         *ced = clock_event_device_uv;
 360         ced->cpumask = cpumask_of(smp_processor_id());
 361         clockevents_register_device(ced);
 362 }
 363
 364 static __init int uv_rtc_setup_clock(void)
 365 {
 366         int rc;
 367
 368         if (!is_uv_system())
 369                 return -ENODEV;
 370
 371         rc = clocksource_register_hz(&clocksource_uv, sn_rtc_cycles_per_second);
 372         if (rc)
 373                 printk(KERN_INFO "UV RTC clocksource failed rc %d\n", rc);
 374         else
 375                 printk(KERN_INFO "UV RTC clocksource registered freq %lu MHz\n",
 376                         sn_rtc_cycles_per_second/(unsigned long)1E6);
 377
 378         if (rc || !uv_rtc_evt_enable || x86_platform_ipi_callback)
 379                 return rc;
 380
 381         /* Setup and register clockevents */
 382         rc = uv_rtc_allocate_timers();
 383         if (rc)
 384                 goto error;
 385
 386         x86_platform_ipi_callback = uv_rtc_interrupt;
 387
 388         clock_event_device_uv.mult = div_sc(sn_rtc_cycles_per_second,
 389                                 NSEC_PER_SEC, clock_event_device_uv.shift);
 390
 391         clock_event_device_uv.min_delta_ns = NSEC_PER_SEC /
 392                                                 sn_rtc_cycles_per_second;
 393
 394         clock_event_device_uv.max_delta_ns = clocksource_uv.mask *
 395                                 (NSEC_PER_SEC / sn_rtc_cycles_per_second);
 396
 397         rc = schedule_on_each_cpu(uv_rtc_register_clockevents);
 398         if (rc) {
 399                 x86_platform_ipi_callback = NULL;
 400                 uv_rtc_deallocate_timers();
 401                 goto error;
 402         }
 403
 404         printk(KERN_INFO "UV RTC clockevents registered\n");
 405
 406         return 0;
 407
 408 error:
 409         clocksource_unregister(&clocksource_uv);
 410         printk(KERN_INFO "UV RTC clockevents failed rc %d\n", rc);
 411
 412         return rc;
 413 }
 414 arch_initcall(uv_rtc_setup_clock);