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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/spinlock.h>
16#include <linux/sched.h>
17#include <linux/interrupt.h>
18#include <linux/profile.h>
19#include <linux/mm.h>
20#include <linux/cpu.h>
21#include <linux/irq.h>
22#include <linux/atomic.h>
23#include <linux/cpumask.h>
24#include <linux/reboot.h>
25#include <linux/irqdomain.h>
26#include <asm/processor.h>
27#include <asm/setup.h>
28#include <asm/mach_desc.h>
29
30#ifndef CONFIG_ARC_HAS_LLSC
31arch_spinlock_t smp_atomic_ops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
32arch_spinlock_t smp_bitops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
33#endif
34
35struct plat_smp_ops __weak plat_smp_ops;
36
37/* XXX: per cpu ? Only needed once in early seconday boot */
38struct task_struct *secondary_idle_tsk;
39
40/* Called from start_kernel */
41void __init smp_prepare_boot_cpu(void)
42{
43}
44
45/*
46 * Called from setup_arch() before calling setup_processor()
47 *
48 * - Initialise the CPU possible map early - this describes the CPUs
49 * which may be present or become present in the system.
50 * - Call early smp init hook. This can initialize a specific multi-core
51 * IP which is say common to several platforms (hence not part of
52 * platform specific int_early() hook)
53 */
54void __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 if (plat_smp_ops.init_early_smp)
62 plat_smp_ops.init_early_smp();
63}
64
65/* called from init ( ) => process 1 */
66void __init smp_prepare_cpus(unsigned int max_cpus)
67{
68 int i;
69
70 /*
71 * if platform didn't set the present map already, do it now
72 * boot cpu is set to present already by init/main.c
73 */
74 if (num_present_cpus() <= 1) {
75 for (i = 0; i < max_cpus; i++)
76 set_cpu_present(i, true);
77 }
78}
79
80void __init smp_cpus_done(unsigned int max_cpus)
81{
82
83}
84
85/*
86 * Default smp boot helper for Run-on-reset case where all cores start off
87 * together. Non-masters need to wait for Master to start running.
88 * This is implemented using a flag in memory, which Non-masters spin-wait on.
89 * Master sets it to cpu-id of core to "ungate" it.
90 */
91static volatile int wake_flag;
92
93#ifdef CONFIG_ISA_ARCOMPACT
94
95#define __boot_read(f) f
96#define __boot_write(f, v) f = v
97
98#else
99
100#define __boot_read(f) arc_read_uncached_32(&f)
101#define __boot_write(f, v) arc_write_uncached_32(&f, v)
102
103#endif
104
105static void arc_default_smp_cpu_kick(int cpu, unsigned long pc)
106{
107 BUG_ON(cpu == 0);
108
109 __boot_write(wake_flag, cpu);
110}
111
112void arc_platform_smp_wait_to_boot(int cpu)
113{
114 /* for halt-on-reset, we've waited already */
115 if (IS_ENABLED(CONFIG_ARC_SMP_HALT_ON_RESET))
116 return;
117
118 while (__boot_read(wake_flag) != cpu)
119 ;
120
121 __boot_write(wake_flag, 0);
122}
123
124const char *arc_platform_smp_cpuinfo(void)
125{
126 return plat_smp_ops.info ? : "";
127}
128
129/*
130 * The very first "C" code executed by secondary
131 * Called from asm stub in head.S
132 * "current"/R25 already setup by low level boot code
133 */
134void start_kernel_secondary(void)
135{
136 struct mm_struct *mm = &init_mm;
137 unsigned int cpu = smp_processor_id();
138
139 /* MMU, Caches, Vector Table, Interrupts etc */
140 setup_processor();
141
142 atomic_inc(&mm->mm_users);
143 atomic_inc(&mm->mm_count);
144 current->active_mm = mm;
145 cpumask_set_cpu(cpu, mm_cpumask(mm));
146
147 /* Some SMP H/w setup - for each cpu */
148 if (plat_smp_ops.init_per_cpu)
149 plat_smp_ops.init_per_cpu(cpu);
150
151 if (machine_desc->init_per_cpu)
152 machine_desc->init_per_cpu(cpu);
153
154 notify_cpu_starting(cpu);
155 set_cpu_online(cpu, true);
156
157 pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu);
158
159 local_irq_enable();
160 preempt_disable();
161 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
162}
163
164/*
165 * Called from kernel_init( ) -> smp_init( ) - for each CPU
166 *
167 * At this point, Secondary Processor is "HALT"ed:
168 * -It booted, but was halted in head.S
169 * -It was configured to halt-on-reset
170 * So need to wake it up.
171 *
172 * Essential requirements being where to run from (PC) and stack (SP)
173*/
174int __cpu_up(unsigned int cpu, struct task_struct *idle)
175{
176 unsigned long wait_till;
177
178 secondary_idle_tsk = idle;
179
180 pr_info("Idle Task [%d] %p", cpu, idle);
181 pr_info("Trying to bring up CPU%u ...\n", cpu);
182
183 if (plat_smp_ops.cpu_kick)
184 plat_smp_ops.cpu_kick(cpu,
185 (unsigned long)first_lines_of_secondary);
186 else
187 arc_default_smp_cpu_kick(cpu, (unsigned long)NULL);
188
189 /* wait for 1 sec after kicking the secondary */
190 wait_till = jiffies + HZ;
191 while (time_before(jiffies, wait_till)) {
192 if (cpu_online(cpu))
193 break;
194 }
195
196 if (!cpu_online(cpu)) {
197 pr_info("Timeout: CPU%u FAILED to comeup !!!\n", cpu);
198 return -1;
199 }
200
201 secondary_idle_tsk = NULL;
202
203 return 0;
204}
205
206/*
207 * not supported here
208 */
209int setup_profiling_timer(unsigned int multiplier)
210{
211 return -EINVAL;
212}
213
214/*****************************************************************************/
215/* Inter Processor Interrupt Handling */
216/*****************************************************************************/
217
218enum ipi_msg_type {
219 IPI_EMPTY = 0,
220 IPI_RESCHEDULE = 1,
221 IPI_CALL_FUNC,
222 IPI_CPU_STOP,
223};
224
225/*
226 * In arches with IRQ for each msg type (above), receiver can use IRQ-id to
227 * figure out what msg was sent. For those which don't (ARC has dedicated IPI
228 * IRQ), the msg-type needs to be conveyed via per-cpu data
229 */
230
231static DEFINE_PER_CPU(unsigned long, ipi_data);
232
233static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg)
234{
235 unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu);
236 unsigned long old, new;
237 unsigned long flags;
238
239 pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu);
240
241 local_irq_save(flags);
242
243 /*
244 * Atomically write new msg bit (in case others are writing too),
245 * and read back old value
246 */
247 do {
248 new = old = ACCESS_ONCE(*ipi_data_ptr);
249 new |= 1U << msg;
250 } while (cmpxchg(ipi_data_ptr, old, new) != old);
251
252 /*
253 * Call the platform specific IPI kick function, but avoid if possible:
254 * Only do so if there's no pending msg from other concurrent sender(s).
255 * Otherwise, recevier will see this msg as well when it takes the
256 * IPI corresponding to that msg. This is true, even if it is already in
257 * IPI handler, because !@old means it has not yet dequeued the msg(s)
258 * so @new msg can be a free-loader
259 */
260 if (plat_smp_ops.ipi_send && !old)
261 plat_smp_ops.ipi_send(cpu);
262
263 local_irq_restore(flags);
264}
265
266static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
267{
268 unsigned int cpu;
269
270 for_each_cpu(cpu, callmap)
271 ipi_send_msg_one(cpu, msg);
272}
273
274void smp_send_reschedule(int cpu)
275{
276 ipi_send_msg_one(cpu, IPI_RESCHEDULE);
277}
278
279void smp_send_stop(void)
280{
281 struct cpumask targets;
282 cpumask_copy(&targets, cpu_online_mask);
283 cpumask_clear_cpu(smp_processor_id(), &targets);
284 ipi_send_msg(&targets, IPI_CPU_STOP);
285}
286
287void arch_send_call_function_single_ipi(int cpu)
288{
289 ipi_send_msg_one(cpu, IPI_CALL_FUNC);
290}
291
292void arch_send_call_function_ipi_mask(const struct cpumask *mask)
293{
294 ipi_send_msg(mask, IPI_CALL_FUNC);
295}
296
297/*
298 * ipi_cpu_stop - handle IPI from smp_send_stop()
299 */
300static void ipi_cpu_stop(void)
301{
302 machine_halt();
303}
304
305static inline int __do_IPI(unsigned long msg)
306{
307 int rc = 0;
308
309 switch (msg) {
310 case IPI_RESCHEDULE:
311 scheduler_ipi();
312 break;
313
314 case IPI_CALL_FUNC:
315 generic_smp_call_function_interrupt();
316 break;
317
318 case IPI_CPU_STOP:
319 ipi_cpu_stop();
320 break;
321
322 default:
323 rc = 1;
324 }
325
326 return rc;
327}
328
329/*
330 * arch-common ISR to handle for inter-processor interrupts
331 * Has hooks for platform specific IPI
332 */
333irqreturn_t do_IPI(int irq, void *dev_id)
334{
335 unsigned long pending;
336 unsigned long __maybe_unused copy;
337
338 pr_debug("IPI [%ld] received on cpu %d\n",
339 *this_cpu_ptr(&ipi_data), smp_processor_id());
340
341 if (plat_smp_ops.ipi_clear)
342 plat_smp_ops.ipi_clear(irq);
343
344 /*
345 * "dequeue" the msg corresponding to this IPI (and possibly other
346 * piggybacked msg from elided IPIs: see ipi_send_msg_one() above)
347 */
348 copy = pending = xchg(this_cpu_ptr(&ipi_data), 0);
349
350 do {
351 unsigned long msg = __ffs(pending);
352 int rc;
353
354 rc = __do_IPI(msg);
355 if (rc)
356 pr_info("IPI with bogus msg %ld in %ld\n", msg, copy);
357 pending &= ~(1U << msg);
358 } while (pending);
359
360 return IRQ_HANDLED;
361}
362
363/*
364 * API called by platform code to hookup arch-common ISR to their IPI IRQ
365 *
366 * Note: If IPI is provided by platform (vs. say ARC MCIP), their intc setup/map
367 * function needs to call call irq_set_percpu_devid() for IPI IRQ, otherwise
368 * request_percpu_irq() below will fail
369 */
370static DEFINE_PER_CPU(int, ipi_dev);
371
372int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq)
373{
374 int *dev = per_cpu_ptr(&ipi_dev, cpu);
375 unsigned int virq = irq_find_mapping(NULL, hwirq);
376
377 if (!virq)
378 panic("Cannot find virq for root domain and hwirq=%lu", hwirq);
379
380 /* Boot cpu calls request, all call enable */
381 if (!cpu) {
382 int rc;
383
384 rc = request_percpu_irq(virq, do_IPI, "IPI Interrupt", dev);
385 if (rc)
386 panic("Percpu IRQ request failed for %u\n", virq);
387 }
388
389 enable_percpu_irq(virq, 0);
390
391 return 0;
392}