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1/*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
12 * more details.
13 *
14 * TILE SMP support routines.
15 */
16
17#include <linux/smp.h>
18#include <linux/interrupt.h>
19#include <linux/io.h>
20#include <linux/irq.h>
21#include <linux/module.h>
22#include <asm/cacheflush.h>
23
24HV_Topology smp_topology __write_once;
25EXPORT_SYMBOL(smp_topology);
26
27#if CHIP_HAS_IPI()
28static unsigned long __iomem *ipi_mappings[NR_CPUS];
29#endif
30
31
32/*
33 * Top-level send_IPI*() functions to send messages to other cpus.
34 */
35
36/* Set by smp_send_stop() to avoid recursive panics. */
37static int stopping_cpus;
38
39static void __send_IPI_many(HV_Recipient *recip, int nrecip, int tag)
40{
41 int sent = 0;
42 while (sent < nrecip) {
43 int rc = hv_send_message(recip, nrecip,
44 (HV_VirtAddr)&tag, sizeof(tag));
45 if (rc < 0) {
46 if (!stopping_cpus) /* avoid recursive panic */
47 panic("hv_send_message returned %d", rc);
48 break;
49 }
50 WARN_ONCE(rc == 0, "hv_send_message() returned zero\n");
51 sent += rc;
52 }
53}
54
55void send_IPI_single(int cpu, int tag)
56{
57 HV_Recipient recip = {
58 .y = cpu / smp_width,
59 .x = cpu % smp_width,
60 .state = HV_TO_BE_SENT
61 };
62 __send_IPI_many(&recip, 1, tag);
63}
64
65void send_IPI_many(const struct cpumask *mask, int tag)
66{
67 HV_Recipient recip[NR_CPUS];
68 int cpu;
69 int nrecip = 0;
70 int my_cpu = smp_processor_id();
71 for_each_cpu(cpu, mask) {
72 HV_Recipient *r;
73 BUG_ON(cpu == my_cpu);
74 r = &recip[nrecip++];
75 r->y = cpu / smp_width;
76 r->x = cpu % smp_width;
77 r->state = HV_TO_BE_SENT;
78 }
79 __send_IPI_many(recip, nrecip, tag);
80}
81
82void send_IPI_allbutself(int tag)
83{
84 struct cpumask mask;
85 cpumask_copy(&mask, cpu_online_mask);
86 cpumask_clear_cpu(smp_processor_id(), &mask);
87 send_IPI_many(&mask, tag);
88}
89
90/*
91 * Functions related to starting/stopping cpus.
92 */
93
94/* Handler to start the current cpu. */
95static void smp_start_cpu_interrupt(void)
96{
97 get_irq_regs()->pc = start_cpu_function_addr;
98}
99
100/* Handler to stop the current cpu. */
101static void smp_stop_cpu_interrupt(void)
102{
103 set_cpu_online(smp_processor_id(), 0);
104 arch_local_irq_disable_all();
105 for (;;)
106 asm("nap; nop");
107}
108
109/* This function calls the 'stop' function on all other CPUs in the system. */
110void smp_send_stop(void)
111{
112 stopping_cpus = 1;
113 send_IPI_allbutself(MSG_TAG_STOP_CPU);
114}
115
116/* On panic, just wait; we may get an smp_send_stop() later on. */
117void panic_smp_self_stop(void)
118{
119 while (1)
120 asm("nap; nop");
121}
122
123/*
124 * Dispatch code called from hv_message_intr() for HV_MSG_TILE hv messages.
125 */
126void evaluate_message(int tag)
127{
128 switch (tag) {
129 case MSG_TAG_START_CPU: /* Start up a cpu */
130 smp_start_cpu_interrupt();
131 break;
132
133 case MSG_TAG_STOP_CPU: /* Sent to shut down slave CPU's */
134 smp_stop_cpu_interrupt();
135 break;
136
137 case MSG_TAG_CALL_FUNCTION_MANY: /* Call function on cpumask */
138 generic_smp_call_function_interrupt();
139 break;
140
141 case MSG_TAG_CALL_FUNCTION_SINGLE: /* Call function on one other CPU */
142 generic_smp_call_function_single_interrupt();
143 break;
144
145 default:
146 panic("Unknown IPI message tag %d", tag);
147 break;
148 }
149}
150
151
152/*
153 * flush_icache_range() code uses smp_call_function().
154 */
155
156struct ipi_flush {
157 unsigned long start;
158 unsigned long end;
159};
160
161static void ipi_flush_icache_range(void *info)
162{
163 struct ipi_flush *flush = (struct ipi_flush *) info;
164 __flush_icache_range(flush->start, flush->end);
165}
166
167void flush_icache_range(unsigned long start, unsigned long end)
168{
169 struct ipi_flush flush = { start, end };
170 preempt_disable();
171 on_each_cpu(ipi_flush_icache_range, &flush, 1);
172 preempt_enable();
173}
174
175
176/* Called when smp_send_reschedule() triggers IRQ_RESCHEDULE. */
177static irqreturn_t handle_reschedule_ipi(int irq, void *token)
178{
179 __get_cpu_var(irq_stat).irq_resched_count++;
180 scheduler_ipi();
181
182 return IRQ_HANDLED;
183}
184
185static struct irqaction resched_action = {
186 .handler = handle_reschedule_ipi,
187 .name = "resched",
188 .dev_id = handle_reschedule_ipi /* unique token */,
189};
190
191void __init ipi_init(void)
192{
193#if CHIP_HAS_IPI()
194 int cpu;
195 /* Map IPI trigger MMIO addresses. */
196 for_each_possible_cpu(cpu) {
197 HV_Coord tile;
198 HV_PTE pte;
199 unsigned long offset;
200
201 tile.x = cpu_x(cpu);
202 tile.y = cpu_y(cpu);
203 if (hv_get_ipi_pte(tile, KERNEL_PL, &pte) != 0)
204 panic("Failed to initialize IPI for cpu %d\n", cpu);
205
206 offset = PFN_PHYS(pte_pfn(pte));
207 ipi_mappings[cpu] = ioremap_prot(offset, PAGE_SIZE, pte);
208 }
209#endif
210
211 /* Bind handle_reschedule_ipi() to IRQ_RESCHEDULE. */
212 tile_irq_activate(IRQ_RESCHEDULE, TILE_IRQ_PERCPU);
213 BUG_ON(setup_irq(IRQ_RESCHEDULE, &resched_action));
214}
215
216#if CHIP_HAS_IPI()
217
218void smp_send_reschedule(int cpu)
219{
220 WARN_ON(cpu_is_offline(cpu));
221
222 /*
223 * We just want to do an MMIO store. The traditional writeq()
224 * functions aren't really correct here, since they're always
225 * directed at the PCI shim. For now, just do a raw store,
226 * casting away the __iomem attribute.
227 */
228 ((unsigned long __force *)ipi_mappings[cpu])[IRQ_RESCHEDULE] = 0;
229}
230
231#else
232
233void smp_send_reschedule(int cpu)
234{
235 HV_Coord coord;
236
237 WARN_ON(cpu_is_offline(cpu));
238
239 coord.y = cpu_y(cpu);
240 coord.x = cpu_x(cpu);
241 hv_trigger_ipi(coord, IRQ_RESCHEDULE);
242}
243
244#endif /* CHIP_HAS_IPI() */
1/*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
12 * more details.
13 *
14 * TILE SMP support routines.
15 */
16
17#include <linux/smp.h>
18#include <linux/interrupt.h>
19#include <linux/io.h>
20#include <linux/irq.h>
21#include <linux/module.h>
22#include <asm/cacheflush.h>
23#include <asm/homecache.h>
24
25/*
26 * We write to width and height with a single store in head_NN.S,
27 * so make the variable aligned to "long".
28 */
29HV_Topology smp_topology __write_once __aligned(sizeof(long));
30EXPORT_SYMBOL(smp_topology);
31
32#if CHIP_HAS_IPI()
33static unsigned long __iomem *ipi_mappings[NR_CPUS];
34#endif
35
36
37/*
38 * Top-level send_IPI*() functions to send messages to other cpus.
39 */
40
41/* Set by smp_send_stop() to avoid recursive panics. */
42static int stopping_cpus;
43
44static void __send_IPI_many(HV_Recipient *recip, int nrecip, int tag)
45{
46 int sent = 0;
47 while (sent < nrecip) {
48 int rc = hv_send_message(recip, nrecip,
49 (HV_VirtAddr)&tag, sizeof(tag));
50 if (rc < 0) {
51 if (!stopping_cpus) /* avoid recursive panic */
52 panic("hv_send_message returned %d", rc);
53 break;
54 }
55 WARN_ONCE(rc == 0, "hv_send_message() returned zero\n");
56 sent += rc;
57 }
58}
59
60void send_IPI_single(int cpu, int tag)
61{
62 HV_Recipient recip = {
63 .y = cpu / smp_width,
64 .x = cpu % smp_width,
65 .state = HV_TO_BE_SENT
66 };
67 __send_IPI_many(&recip, 1, tag);
68}
69
70void send_IPI_many(const struct cpumask *mask, int tag)
71{
72 HV_Recipient recip[NR_CPUS];
73 int cpu;
74 int nrecip = 0;
75 int my_cpu = smp_processor_id();
76 for_each_cpu(cpu, mask) {
77 HV_Recipient *r;
78 BUG_ON(cpu == my_cpu);
79 r = &recip[nrecip++];
80 r->y = cpu / smp_width;
81 r->x = cpu % smp_width;
82 r->state = HV_TO_BE_SENT;
83 }
84 __send_IPI_many(recip, nrecip, tag);
85}
86
87void send_IPI_allbutself(int tag)
88{
89 struct cpumask mask;
90 cpumask_copy(&mask, cpu_online_mask);
91 cpumask_clear_cpu(smp_processor_id(), &mask);
92 send_IPI_many(&mask, tag);
93}
94
95/*
96 * Functions related to starting/stopping cpus.
97 */
98
99/* Handler to start the current cpu. */
100static void smp_start_cpu_interrupt(void)
101{
102 get_irq_regs()->pc = start_cpu_function_addr;
103}
104
105/* Handler to stop the current cpu. */
106static void smp_stop_cpu_interrupt(void)
107{
108 arch_local_irq_disable_all();
109 set_cpu_online(smp_processor_id(), 0);
110 for (;;)
111 asm("nap; nop");
112}
113
114/* This function calls the 'stop' function on all other CPUs in the system. */
115void smp_send_stop(void)
116{
117 stopping_cpus = 1;
118 send_IPI_allbutself(MSG_TAG_STOP_CPU);
119}
120
121/* On panic, just wait; we may get an smp_send_stop() later on. */
122void panic_smp_self_stop(void)
123{
124 while (1)
125 asm("nap; nop");
126}
127
128/*
129 * Dispatch code called from hv_message_intr() for HV_MSG_TILE hv messages.
130 */
131void evaluate_message(int tag)
132{
133 switch (tag) {
134 case MSG_TAG_START_CPU: /* Start up a cpu */
135 smp_start_cpu_interrupt();
136 break;
137
138 case MSG_TAG_STOP_CPU: /* Sent to shut down slave CPU's */
139 smp_stop_cpu_interrupt();
140 break;
141
142 case MSG_TAG_CALL_FUNCTION_MANY: /* Call function on cpumask */
143 generic_smp_call_function_interrupt();
144 break;
145
146 case MSG_TAG_CALL_FUNCTION_SINGLE: /* Call function on one other CPU */
147 generic_smp_call_function_single_interrupt();
148 break;
149
150 default:
151 panic("Unknown IPI message tag %d", tag);
152 break;
153 }
154}
155
156
157/*
158 * flush_icache_range() code uses smp_call_function().
159 */
160
161struct ipi_flush {
162 unsigned long start;
163 unsigned long end;
164};
165
166static void ipi_flush_icache_range(void *info)
167{
168 struct ipi_flush *flush = (struct ipi_flush *) info;
169 __flush_icache_range(flush->start, flush->end);
170}
171
172void flush_icache_range(unsigned long start, unsigned long end)
173{
174 struct ipi_flush flush = { start, end };
175
176 /* If invoked with irqs disabled, we can not issue IPIs. */
177 if (irqs_disabled())
178 flush_remote(0, HV_FLUSH_EVICT_L1I, NULL, 0, 0, 0,
179 NULL, NULL, 0);
180 else {
181 preempt_disable();
182 on_each_cpu(ipi_flush_icache_range, &flush, 1);
183 preempt_enable();
184 }
185}
186
187
188/* Called when smp_send_reschedule() triggers IRQ_RESCHEDULE. */
189static irqreturn_t handle_reschedule_ipi(int irq, void *token)
190{
191 __get_cpu_var(irq_stat).irq_resched_count++;
192 scheduler_ipi();
193
194 return IRQ_HANDLED;
195}
196
197static struct irqaction resched_action = {
198 .handler = handle_reschedule_ipi,
199 .name = "resched",
200 .dev_id = handle_reschedule_ipi /* unique token */,
201};
202
203void __init ipi_init(void)
204{
205#if CHIP_HAS_IPI()
206 int cpu;
207 /* Map IPI trigger MMIO addresses. */
208 for_each_possible_cpu(cpu) {
209 HV_Coord tile;
210 HV_PTE pte;
211 unsigned long offset;
212
213 tile.x = cpu_x(cpu);
214 tile.y = cpu_y(cpu);
215 if (hv_get_ipi_pte(tile, KERNEL_PL, &pte) != 0)
216 panic("Failed to initialize IPI for cpu %d\n", cpu);
217
218 offset = PFN_PHYS(pte_pfn(pte));
219 ipi_mappings[cpu] = ioremap_prot(offset, PAGE_SIZE, pte);
220 }
221#endif
222
223 /* Bind handle_reschedule_ipi() to IRQ_RESCHEDULE. */
224 tile_irq_activate(IRQ_RESCHEDULE, TILE_IRQ_PERCPU);
225 BUG_ON(setup_irq(IRQ_RESCHEDULE, &resched_action));
226}
227
228#if CHIP_HAS_IPI()
229
230void smp_send_reschedule(int cpu)
231{
232 WARN_ON(cpu_is_offline(cpu));
233
234 /*
235 * We just want to do an MMIO store. The traditional writeq()
236 * functions aren't really correct here, since they're always
237 * directed at the PCI shim. For now, just do a raw store,
238 * casting away the __iomem attribute.
239 */
240 ((unsigned long __force *)ipi_mappings[cpu])[IRQ_RESCHEDULE] = 0;
241}
242
243#else
244
245void smp_send_reschedule(int cpu)
246{
247 HV_Coord coord;
248
249 WARN_ON(cpu_is_offline(cpu));
250
251 coord.y = cpu_y(cpu);
252 coord.x = cpu_x(cpu);
253 hv_trigger_ipi(coord, IRQ_RESCHEDULE);
254}
255
256#endif /* CHIP_HAS_IPI() */