Merge tag 'regulator-v3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie...
[deliverable/linux.git] / arch / arc / kernel / smp.c
1 /*
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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 version 2 as
6 * published by the Free Software Foundation.
7 *
8 * RajeshwarR: Dec 11, 2007
9 * -- Added support for Inter Processor Interrupts
10 *
11 * Vineetg: Nov 1st, 2007
12 * -- Initial Write (Borrowed heavily from ARM)
13 */
14
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/spinlock.h>
18 #include <linux/sched.h>
19 #include <linux/interrupt.h>
20 #include <linux/profile.h>
21 #include <linux/errno.h>
22 #include <linux/err.h>
23 #include <linux/mm.h>
24 #include <linux/cpu.h>
25 #include <linux/smp.h>
26 #include <linux/irq.h>
27 #include <linux/delay.h>
28 #include <linux/atomic.h>
29 #include <linux/percpu.h>
30 #include <linux/cpumask.h>
31 #include <linux/spinlock_types.h>
32 #include <linux/reboot.h>
33 #include <asm/processor.h>
34 #include <asm/setup.h>
35 #include <asm/mach_desc.h>
36
37 arch_spinlock_t smp_atomic_ops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
38 arch_spinlock_t smp_bitops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
39
40 struct plat_smp_ops plat_smp_ops;
41
42 /* XXX: per cpu ? Only needed once in early seconday boot */
43 struct task_struct *secondary_idle_tsk;
44
45 /* Called from start_kernel */
46 void __init smp_prepare_boot_cpu(void)
47 {
48 }
49
50 /*
51 * Initialise the CPU possible map early - this describes the CPUs
52 * which may be present or become present in the system.
53 */
54 void __init smp_init_cpus(void)
55 {
56 unsigned int i;
57
58 for (i = 0; i < NR_CPUS; i++)
59 set_cpu_possible(i, true);
60 }
61
62 /* called from init ( ) => process 1 */
63 void __init smp_prepare_cpus(unsigned int max_cpus)
64 {
65 int i;
66
67 /*
68 * Initialise the present map, which describes the set of CPUs
69 * actually populated at the present time.
70 */
71 for (i = 0; i < max_cpus; i++)
72 set_cpu_present(i, true);
73 }
74
75 void __init smp_cpus_done(unsigned int max_cpus)
76 {
77
78 }
79
80 /*
81 * After power-up, a non Master CPU needs to wait for Master to kick start it
82 *
83 * The default implementation halts
84 *
85 * This relies on platform specific support allowing Master to directly set
86 * this CPU's PC (to be @first_lines_of_secondary() and kick start it.
87 *
88 * In lack of such h/w assist, platforms can override this function
89 * - make this function busy-spin on a token, eventually set by Master
90 * (from arc_platform_smp_wakeup_cpu())
91 * - Once token is available, jump to @first_lines_of_secondary
92 * (using inline asm).
93 *
94 * Alert: can NOT use stack here as it has not been determined/setup for CPU.
95 * If it turns out to be elaborate, it's better to code it in assembly
96 *
97 */
98 void __weak arc_platform_smp_wait_to_boot(int cpu)
99 {
100 /*
101 * As a hack for debugging - since debugger will single-step over the
102 * FLAG insn - wrap the halt itself it in a self loop
103 */
104 __asm__ __volatile__(
105 "1: \n"
106 " flag 1 \n"
107 " b 1b \n");
108 }
109
110 const char *arc_platform_smp_cpuinfo(void)
111 {
112 return plat_smp_ops.info;
113 }
114
115 /*
116 * The very first "C" code executed by secondary
117 * Called from asm stub in head.S
118 * "current"/R25 already setup by low level boot code
119 */
120 void start_kernel_secondary(void)
121 {
122 struct mm_struct *mm = &init_mm;
123 unsigned int cpu = smp_processor_id();
124
125 /* MMU, Caches, Vector Table, Interrupts etc */
126 setup_processor();
127
128 atomic_inc(&mm->mm_users);
129 atomic_inc(&mm->mm_count);
130 current->active_mm = mm;
131 cpumask_set_cpu(cpu, mm_cpumask(mm));
132
133 notify_cpu_starting(cpu);
134 set_cpu_online(cpu, true);
135
136 pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu);
137
138 if (machine_desc->init_smp)
139 machine_desc->init_smp(smp_processor_id());
140
141 arc_local_timer_setup(cpu);
142
143 local_irq_enable();
144 preempt_disable();
145 cpu_startup_entry(CPUHP_ONLINE);
146 }
147
148 /*
149 * Called from kernel_init( ) -> smp_init( ) - for each CPU
150 *
151 * At this point, Secondary Processor is "HALT"ed:
152 * -It booted, but was halted in head.S
153 * -It was configured to halt-on-reset
154 * So need to wake it up.
155 *
156 * Essential requirements being where to run from (PC) and stack (SP)
157 */
158 int __cpu_up(unsigned int cpu, struct task_struct *idle)
159 {
160 unsigned long wait_till;
161
162 secondary_idle_tsk = idle;
163
164 pr_info("Idle Task [%d] %p", cpu, idle);
165 pr_info("Trying to bring up CPU%u ...\n", cpu);
166
167 if (plat_smp_ops.cpu_kick)
168 plat_smp_ops.cpu_kick(cpu,
169 (unsigned long)first_lines_of_secondary);
170
171 /* wait for 1 sec after kicking the secondary */
172 wait_till = jiffies + HZ;
173 while (time_before(jiffies, wait_till)) {
174 if (cpu_online(cpu))
175 break;
176 }
177
178 if (!cpu_online(cpu)) {
179 pr_info("Timeout: CPU%u FAILED to comeup !!!\n", cpu);
180 return -1;
181 }
182
183 secondary_idle_tsk = NULL;
184
185 return 0;
186 }
187
188 /*
189 * not supported here
190 */
191 int __init setup_profiling_timer(unsigned int multiplier)
192 {
193 return -EINVAL;
194 }
195
196 /*****************************************************************************/
197 /* Inter Processor Interrupt Handling */
198 /*****************************************************************************/
199
200 /*
201 * structures for inter-processor calls
202 * A Collection of single bit ipi messages
203 *
204 */
205
206 /*
207 * TODO_rajesh investigate tlb message types.
208 * IPI Timer not needed because each ARC has an individual Interrupting Timer
209 */
210 enum ipi_msg_type {
211 IPI_NOP = 0,
212 IPI_RESCHEDULE = 1,
213 IPI_CALL_FUNC,
214 IPI_CPU_STOP
215 };
216
217 struct ipi_data {
218 unsigned long bits;
219 };
220
221 static DEFINE_PER_CPU(struct ipi_data, ipi_data);
222
223 static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
224 {
225 unsigned long flags;
226 unsigned int cpu;
227
228 local_irq_save(flags);
229
230 for_each_cpu(cpu, callmap) {
231 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
232 set_bit(msg, &ipi->bits);
233 }
234
235 /* Call the platform specific cross-CPU call function */
236 if (plat_smp_ops.ipi_send)
237 plat_smp_ops.ipi_send((void *)callmap);
238
239 local_irq_restore(flags);
240 }
241
242 void smp_send_reschedule(int cpu)
243 {
244 ipi_send_msg(cpumask_of(cpu), IPI_RESCHEDULE);
245 }
246
247 void smp_send_stop(void)
248 {
249 struct cpumask targets;
250 cpumask_copy(&targets, cpu_online_mask);
251 cpumask_clear_cpu(smp_processor_id(), &targets);
252 ipi_send_msg(&targets, IPI_CPU_STOP);
253 }
254
255 void arch_send_call_function_single_ipi(int cpu)
256 {
257 ipi_send_msg(cpumask_of(cpu), IPI_CALL_FUNC);
258 }
259
260 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
261 {
262 ipi_send_msg(mask, IPI_CALL_FUNC);
263 }
264
265 /*
266 * ipi_cpu_stop - handle IPI from smp_send_stop()
267 */
268 static void ipi_cpu_stop(unsigned int cpu)
269 {
270 machine_halt();
271 }
272
273 static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi, int cpu)
274 {
275 unsigned long msg = 0;
276
277 do {
278 msg = find_next_bit(ops, BITS_PER_LONG, msg+1);
279
280 switch (msg) {
281 case IPI_RESCHEDULE:
282 scheduler_ipi();
283 break;
284
285 case IPI_CALL_FUNC:
286 generic_smp_call_function_interrupt();
287 break;
288
289 case IPI_CPU_STOP:
290 ipi_cpu_stop(cpu);
291 break;
292 }
293 } while (msg < BITS_PER_LONG);
294
295 }
296
297 /*
298 * arch-common ISR to handle for inter-processor interrupts
299 * Has hooks for platform specific IPI
300 */
301 irqreturn_t do_IPI(int irq, void *dev_id)
302 {
303 int cpu = smp_processor_id();
304 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
305 unsigned long ops;
306
307 if (plat_smp_ops.ipi_clear)
308 plat_smp_ops.ipi_clear(cpu, irq);
309
310 /*
311 * XXX: is this loop really needed
312 * And do we need to move ipi_clean inside
313 */
314 while ((ops = xchg(&ipi->bits, 0)) != 0)
315 __do_IPI(&ops, ipi, cpu);
316
317 return IRQ_HANDLED;
318 }
319
320 /*
321 * API called by platform code to hookup arch-common ISR to their IPI IRQ
322 */
323 static DEFINE_PER_CPU(int, ipi_dev);
324 int smp_ipi_irq_setup(int cpu, int irq)
325 {
326 int *dev_id = &per_cpu(ipi_dev, smp_processor_id());
327 return request_percpu_irq(irq, do_IPI, "IPI Interrupt", dev_id);
328 }
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