Zachary Amsden | e0bb864 | 2007-05-02 19:27:16 +0200 | [diff] [blame] | 1 | /* |
| 2 | * VMI paravirtual timer support routines. |
| 3 | * |
| 4 | * Copyright (C) 2007, VMware, Inc. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, but |
| 12 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or |
| 14 | * NON INFRINGEMENT. See the GNU General Public License for more |
| 15 | * details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, write to the Free Software |
| 19 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #include <linux/smp.h> |
| 24 | #include <linux/interrupt.h> |
| 25 | #include <linux/cpumask.h> |
| 26 | #include <linux/clocksource.h> |
| 27 | #include <linux/clockchips.h> |
| 28 | |
| 29 | #include <asm/vmi.h> |
| 30 | #include <asm/vmi_time.h> |
| 31 | #include <asm/arch_hooks.h> |
| 32 | #include <asm/apicdef.h> |
| 33 | #include <asm/apic.h> |
| 34 | #include <asm/timer.h> |
Thomas Gleixner | a290097 | 2007-07-21 17:11:34 +0200 | [diff] [blame] | 35 | #include <asm/i8253.h> |
Zachary Amsden | e0bb864 | 2007-05-02 19:27:16 +0200 | [diff] [blame] | 36 | |
| 37 | #include <irq_vectors.h> |
| 38 | #include "io_ports.h" |
| 39 | |
| 40 | #define VMI_ONESHOT (VMI_ALARM_IS_ONESHOT | VMI_CYCLES_REAL | vmi_get_alarm_wiring()) |
| 41 | #define VMI_PERIODIC (VMI_ALARM_IS_PERIODIC | VMI_CYCLES_REAL | vmi_get_alarm_wiring()) |
| 42 | |
| 43 | static DEFINE_PER_CPU(struct clock_event_device, local_events); |
| 44 | |
| 45 | static inline u32 vmi_counter(u32 flags) |
| 46 | { |
| 47 | /* Given VMI_ONESHOT or VMI_PERIODIC, return the corresponding |
| 48 | * cycle counter. */ |
| 49 | return flags & VMI_ALARM_COUNTER_MASK; |
| 50 | } |
| 51 | |
| 52 | /* paravirt_ops.get_wallclock = vmi_get_wallclock */ |
| 53 | unsigned long vmi_get_wallclock(void) |
| 54 | { |
| 55 | unsigned long long wallclock; |
| 56 | wallclock = vmi_timer_ops.get_wallclock(); // nsec |
| 57 | (void)do_div(wallclock, 1000000000); // sec |
| 58 | |
| 59 | return wallclock; |
| 60 | } |
| 61 | |
| 62 | /* paravirt_ops.set_wallclock = vmi_set_wallclock */ |
| 63 | int vmi_set_wallclock(unsigned long now) |
| 64 | { |
| 65 | return 0; |
| 66 | } |
| 67 | |
Jeremy Fitzhardinge | 688340e | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 68 | /* paravirt_ops.sched_clock = vmi_sched_clock */ |
| 69 | unsigned long long vmi_sched_clock(void) |
Zachary Amsden | e0bb864 | 2007-05-02 19:27:16 +0200 | [diff] [blame] | 70 | { |
Jeremy Fitzhardinge | 688340e | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 71 | return cycles_2_ns(vmi_timer_ops.get_cycle_counter(VMI_CYCLES_AVAILABLE)); |
Zachary Amsden | e0bb864 | 2007-05-02 19:27:16 +0200 | [diff] [blame] | 72 | } |
| 73 | |
| 74 | /* paravirt_ops.get_cpu_khz = vmi_cpu_khz */ |
| 75 | unsigned long vmi_cpu_khz(void) |
| 76 | { |
| 77 | unsigned long long khz; |
| 78 | khz = vmi_timer_ops.get_cycle_frequency(); |
| 79 | (void)do_div(khz, 1000); |
| 80 | return khz; |
| 81 | } |
| 82 | |
| 83 | static inline unsigned int vmi_get_timer_vector(void) |
| 84 | { |
| 85 | #ifdef CONFIG_X86_IO_APIC |
| 86 | return FIRST_DEVICE_VECTOR; |
| 87 | #else |
| 88 | return FIRST_EXTERNAL_VECTOR; |
| 89 | #endif |
| 90 | } |
| 91 | |
| 92 | /** vmi clockchip */ |
| 93 | #ifdef CONFIG_X86_LOCAL_APIC |
| 94 | static unsigned int startup_timer_irq(unsigned int irq) |
| 95 | { |
| 96 | unsigned long val = apic_read(APIC_LVTT); |
| 97 | apic_write(APIC_LVTT, vmi_get_timer_vector()); |
| 98 | |
| 99 | return (val & APIC_SEND_PENDING); |
| 100 | } |
| 101 | |
| 102 | static void mask_timer_irq(unsigned int irq) |
| 103 | { |
| 104 | unsigned long val = apic_read(APIC_LVTT); |
| 105 | apic_write(APIC_LVTT, val | APIC_LVT_MASKED); |
| 106 | } |
| 107 | |
| 108 | static void unmask_timer_irq(unsigned int irq) |
| 109 | { |
| 110 | unsigned long val = apic_read(APIC_LVTT); |
| 111 | apic_write(APIC_LVTT, val & ~APIC_LVT_MASKED); |
| 112 | } |
| 113 | |
| 114 | static void ack_timer_irq(unsigned int irq) |
| 115 | { |
| 116 | ack_APIC_irq(); |
| 117 | } |
| 118 | |
| 119 | static struct irq_chip vmi_chip __read_mostly = { |
| 120 | .name = "VMI-LOCAL", |
| 121 | .startup = startup_timer_irq, |
| 122 | .mask = mask_timer_irq, |
| 123 | .unmask = unmask_timer_irq, |
| 124 | .ack = ack_timer_irq |
| 125 | }; |
| 126 | #endif |
| 127 | |
| 128 | /** vmi clockevent */ |
| 129 | #define VMI_ALARM_WIRED_IRQ0 0x00000000 |
| 130 | #define VMI_ALARM_WIRED_LVTT 0x00010000 |
| 131 | static int vmi_wiring = VMI_ALARM_WIRED_IRQ0; |
| 132 | |
| 133 | static inline int vmi_get_alarm_wiring(void) |
| 134 | { |
| 135 | return vmi_wiring; |
| 136 | } |
| 137 | |
| 138 | static void vmi_timer_set_mode(enum clock_event_mode mode, |
| 139 | struct clock_event_device *evt) |
| 140 | { |
| 141 | cycle_t now, cycles_per_hz; |
| 142 | BUG_ON(!irqs_disabled()); |
| 143 | |
| 144 | switch (mode) { |
| 145 | case CLOCK_EVT_MODE_ONESHOT: |
Thomas Gleixner | 18de5bc | 2007-07-21 04:37:34 -0700 | [diff] [blame] | 146 | case CLOCK_EVT_MODE_RESUME: |
Zachary Amsden | e0bb864 | 2007-05-02 19:27:16 +0200 | [diff] [blame] | 147 | break; |
| 148 | case CLOCK_EVT_MODE_PERIODIC: |
| 149 | cycles_per_hz = vmi_timer_ops.get_cycle_frequency(); |
| 150 | (void)do_div(cycles_per_hz, HZ); |
| 151 | now = vmi_timer_ops.get_cycle_counter(vmi_counter(VMI_PERIODIC)); |
| 152 | vmi_timer_ops.set_alarm(VMI_PERIODIC, now, cycles_per_hz); |
| 153 | break; |
| 154 | case CLOCK_EVT_MODE_UNUSED: |
| 155 | case CLOCK_EVT_MODE_SHUTDOWN: |
| 156 | switch (evt->mode) { |
| 157 | case CLOCK_EVT_MODE_ONESHOT: |
| 158 | vmi_timer_ops.cancel_alarm(VMI_ONESHOT); |
| 159 | break; |
| 160 | case CLOCK_EVT_MODE_PERIODIC: |
| 161 | vmi_timer_ops.cancel_alarm(VMI_PERIODIC); |
| 162 | break; |
| 163 | default: |
| 164 | break; |
| 165 | } |
| 166 | break; |
| 167 | default: |
| 168 | break; |
| 169 | } |
| 170 | } |
| 171 | |
| 172 | static int vmi_timer_next_event(unsigned long delta, |
| 173 | struct clock_event_device *evt) |
| 174 | { |
| 175 | /* Unfortunately, set_next_event interface only passes relative |
| 176 | * expiry, but we want absolute expiry. It'd be better if were |
| 177 | * were passed an aboslute expiry, since a bunch of time may |
| 178 | * have been stolen between the time the delta is computed and |
| 179 | * when we set the alarm below. */ |
| 180 | cycle_t now = vmi_timer_ops.get_cycle_counter(vmi_counter(VMI_ONESHOT)); |
| 181 | |
| 182 | BUG_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT); |
| 183 | vmi_timer_ops.set_alarm(VMI_ONESHOT, now + delta, 0); |
| 184 | return 0; |
| 185 | } |
| 186 | |
| 187 | static struct clock_event_device vmi_clockevent = { |
| 188 | .name = "vmi-timer", |
| 189 | .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, |
| 190 | .shift = 22, |
| 191 | .set_mode = vmi_timer_set_mode, |
| 192 | .set_next_event = vmi_timer_next_event, |
| 193 | .rating = 1000, |
| 194 | .irq = 0, |
| 195 | }; |
| 196 | |
| 197 | static irqreturn_t vmi_timer_interrupt(int irq, void *dev_id) |
| 198 | { |
| 199 | struct clock_event_device *evt = &__get_cpu_var(local_events); |
| 200 | evt->event_handler(evt); |
| 201 | return IRQ_HANDLED; |
| 202 | } |
| 203 | |
| 204 | static struct irqaction vmi_clock_action = { |
| 205 | .name = "vmi-timer", |
| 206 | .handler = vmi_timer_interrupt, |
| 207 | .flags = IRQF_DISABLED | IRQF_NOBALANCING, |
| 208 | .mask = CPU_MASK_ALL, |
| 209 | }; |
| 210 | |
| 211 | static void __devinit vmi_time_init_clockevent(void) |
| 212 | { |
| 213 | cycle_t cycles_per_msec; |
| 214 | struct clock_event_device *evt; |
| 215 | |
| 216 | int cpu = smp_processor_id(); |
| 217 | evt = &__get_cpu_var(local_events); |
| 218 | |
| 219 | /* Use cycles_per_msec since div_sc params are 32-bits. */ |
| 220 | cycles_per_msec = vmi_timer_ops.get_cycle_frequency(); |
| 221 | (void)do_div(cycles_per_msec, 1000); |
| 222 | |
| 223 | memcpy(evt, &vmi_clockevent, sizeof(*evt)); |
| 224 | /* Must pick .shift such that .mult fits in 32-bits. Choosing |
| 225 | * .shift to be 22 allows 2^(32-22) cycles per nano-seconds |
| 226 | * before overflow. */ |
| 227 | evt->mult = div_sc(cycles_per_msec, NSEC_PER_MSEC, evt->shift); |
| 228 | /* Upper bound is clockevent's use of ulong for cycle deltas. */ |
| 229 | evt->max_delta_ns = clockevent_delta2ns(ULONG_MAX, evt); |
| 230 | evt->min_delta_ns = clockevent_delta2ns(1, evt); |
| 231 | evt->cpumask = cpumask_of_cpu(cpu); |
| 232 | |
| 233 | printk(KERN_WARNING "vmi: registering clock event %s. mult=%lu shift=%u\n", |
| 234 | evt->name, evt->mult, evt->shift); |
| 235 | clockevents_register_device(evt); |
| 236 | } |
| 237 | |
| 238 | void __init vmi_time_init(void) |
| 239 | { |
| 240 | /* Disable PIT: BIOSes start PIT CH0 with 18.2hz peridic. */ |
| 241 | outb_p(0x3a, PIT_MODE); /* binary, mode 5, LSB/MSB, ch 0 */ |
| 242 | |
| 243 | vmi_time_init_clockevent(); |
| 244 | setup_irq(0, &vmi_clock_action); |
| 245 | } |
| 246 | |
| 247 | #ifdef CONFIG_X86_LOCAL_APIC |
| 248 | void __devinit vmi_time_bsp_init(void) |
| 249 | { |
| 250 | /* |
| 251 | * On APIC systems, we want local timers to fire on each cpu. We do |
| 252 | * this by programming LVTT to deliver timer events to the IRQ handler |
| 253 | * for IRQ-0, since we can't re-use the APIC local timer handler |
| 254 | * without interfering with that code. |
| 255 | */ |
| 256 | clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); |
| 257 | local_irq_disable(); |
| 258 | #ifdef CONFIG_X86_SMP |
| 259 | /* |
| 260 | * XXX handle_percpu_irq only defined for SMP; we need to switch over |
| 261 | * to using it, since this is a local interrupt, which each CPU must |
| 262 | * handle individually without locking out or dropping simultaneous |
| 263 | * local timers on other CPUs. We also don't want to trigger the |
| 264 | * quirk workaround code for interrupts which gets invoked from |
| 265 | * handle_percpu_irq via eoi, so we use our own IRQ chip. |
| 266 | */ |
| 267 | set_irq_chip_and_handler_name(0, &vmi_chip, handle_percpu_irq, "lvtt"); |
| 268 | #else |
| 269 | set_irq_chip_and_handler_name(0, &vmi_chip, handle_edge_irq, "lvtt"); |
| 270 | #endif |
| 271 | vmi_wiring = VMI_ALARM_WIRED_LVTT; |
| 272 | apic_write(APIC_LVTT, vmi_get_timer_vector()); |
| 273 | local_irq_enable(); |
| 274 | clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); |
| 275 | } |
| 276 | |
| 277 | void __devinit vmi_time_ap_init(void) |
| 278 | { |
| 279 | vmi_time_init_clockevent(); |
| 280 | apic_write(APIC_LVTT, vmi_get_timer_vector()); |
| 281 | } |
| 282 | #endif |
| 283 | |
| 284 | /** vmi clocksource */ |
| 285 | |
| 286 | static cycle_t read_real_cycles(void) |
| 287 | { |
| 288 | return vmi_timer_ops.get_cycle_counter(VMI_CYCLES_REAL); |
| 289 | } |
| 290 | |
| 291 | static struct clocksource clocksource_vmi = { |
| 292 | .name = "vmi-timer", |
| 293 | .rating = 450, |
| 294 | .read = read_real_cycles, |
| 295 | .mask = CLOCKSOURCE_MASK(64), |
| 296 | .mult = 0, /* to be set */ |
| 297 | .shift = 22, |
| 298 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
| 299 | }; |
| 300 | |
| 301 | static int __init init_vmi_clocksource(void) |
| 302 | { |
| 303 | cycle_t cycles_per_msec; |
| 304 | |
| 305 | if (!vmi_timer_ops.get_cycle_frequency) |
| 306 | return 0; |
| 307 | /* Use khz2mult rather than hz2mult since hz arg is only 32-bits. */ |
| 308 | cycles_per_msec = vmi_timer_ops.get_cycle_frequency(); |
| 309 | (void)do_div(cycles_per_msec, 1000); |
| 310 | |
| 311 | /* Note that clocksource.{mult, shift} converts in the opposite direction |
| 312 | * as clockevents. */ |
| 313 | clocksource_vmi.mult = clocksource_khz2mult(cycles_per_msec, |
| 314 | clocksource_vmi.shift); |
| 315 | |
| 316 | printk(KERN_WARNING "vmi: registering clock source khz=%lld\n", cycles_per_msec); |
| 317 | return clocksource_register(&clocksource_vmi); |
| 318 | |
| 319 | } |
| 320 | module_init(init_vmi_clocksource); |