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e0bb8643 ZA |
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> | |
a2900975 | 35 | #include <asm/i8253.h> |
e0bb8643 ZA |
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 | ||
688340ea JF |
68 | /* paravirt_ops.sched_clock = vmi_sched_clock */ |
69 | unsigned long long vmi_sched_clock(void) | |
e0bb8643 | 70 | { |
688340ea | 71 | return cycles_2_ns(vmi_timer_ops.get_cycle_counter(VMI_CYCLES_AVAILABLE)); |
e0bb8643 ZA |
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: | |
18de5bc4 | 146 | case CLOCK_EVT_MODE_RESUME: |
e0bb8643 ZA |
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); |