2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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.
8 * RajeshwarR: Dec 11, 2007
9 * -- Added support for Inter Processor Interrupts
11 * Vineetg: Nov 1st, 2007
12 * -- Initial Write (Borrowed heavily from ARM)
15 #include <linux/spinlock.h>
16 #include <linux/sched/mm.h>
17 #include <linux/interrupt.h>
18 #include <linux/profile.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>
30 #ifndef CONFIG_ARC_HAS_LLSC
31 arch_spinlock_t smp_atomic_ops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
32 arch_spinlock_t smp_bitops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
35 struct plat_smp_ops __weak plat_smp_ops;
37 /* XXX: per cpu ? Only needed once in early seconday boot */
38 struct task_struct *secondary_idle_tsk;
40 /* Called from start_kernel */
41 void __init smp_prepare_boot_cpu(void)
46 * Called from setup_arch() before calling setup_processor()
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)
54 void __init smp_init_cpus(void)
58 for (i = 0; i < NR_CPUS; i++)
59 set_cpu_possible(i, true);
61 if (plat_smp_ops.init_early_smp)
62 plat_smp_ops.init_early_smp();
65 /* called from init ( ) => process 1 */
66 void __init smp_prepare_cpus(unsigned int max_cpus)
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
74 if (num_present_cpus() <= 1) {
75 for (i = 0; i < max_cpus; i++)
76 set_cpu_present(i, true);
80 void __init smp_cpus_done(unsigned int max_cpus)
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.
91 static volatile int wake_flag;
93 #ifdef CONFIG_ISA_ARCOMPACT
95 #define __boot_read(f) f
96 #define __boot_write(f, v) f = v
100 #define __boot_read(f) arc_read_uncached_32(&f)
101 #define __boot_write(f, v) arc_write_uncached_32(&f, v)
105 static void arc_default_smp_cpu_kick(int cpu, unsigned long pc)
109 __boot_write(wake_flag, cpu);
112 void arc_platform_smp_wait_to_boot(int cpu)
114 /* for halt-on-reset, we've waited already */
115 if (IS_ENABLED(CONFIG_ARC_SMP_HALT_ON_RESET))
118 while (__boot_read(wake_flag) != cpu)
121 __boot_write(wake_flag, 0);
124 const char *arc_platform_smp_cpuinfo(void)
126 return plat_smp_ops.info ? : "";
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
134 void start_kernel_secondary(void)
136 struct mm_struct *mm = &init_mm;
137 unsigned int cpu = smp_processor_id();
139 /* MMU, Caches, Vector Table, Interrupts etc */
144 current->active_mm = mm;
145 cpumask_set_cpu(cpu, mm_cpumask(mm));
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);
151 if (machine_desc->init_per_cpu)
152 machine_desc->init_per_cpu(cpu);
154 notify_cpu_starting(cpu);
155 set_cpu_online(cpu, true);
157 pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu);
161 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
165 * Called from kernel_init( ) -> smp_init( ) - for each CPU
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.
172 * Essential requirements being where to run from (PC) and stack (SP)
174 int __cpu_up(unsigned int cpu, struct task_struct *idle)
176 unsigned long wait_till;
178 secondary_idle_tsk = idle;
180 pr_info("Idle Task [%d] %p", cpu, idle);
181 pr_info("Trying to bring up CPU%u ...\n", cpu);
183 if (plat_smp_ops.cpu_kick)
184 plat_smp_ops.cpu_kick(cpu,
185 (unsigned long)first_lines_of_secondary);
187 arc_default_smp_cpu_kick(cpu, (unsigned long)NULL);
189 /* wait for 1 sec after kicking the secondary */
190 wait_till = jiffies + HZ;
191 while (time_before(jiffies, wait_till)) {
196 if (!cpu_online(cpu)) {
197 pr_info("Timeout: CPU%u FAILED to comeup !!!\n", cpu);
201 secondary_idle_tsk = NULL;
209 int setup_profiling_timer(unsigned int multiplier)
214 /*****************************************************************************/
215 /* Inter Processor Interrupt Handling */
216 /*****************************************************************************/
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
231 static DEFINE_PER_CPU(unsigned long, ipi_data);
233 static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg)
235 unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu);
236 unsigned long old, new;
239 pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu);
241 local_irq_save(flags);
244 * Atomically write new msg bit (in case others are writing too),
245 * and read back old value
248 new = old = ACCESS_ONCE(*ipi_data_ptr);
250 } while (cmpxchg(ipi_data_ptr, old, new) != old);
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
260 if (plat_smp_ops.ipi_send && !old)
261 plat_smp_ops.ipi_send(cpu);
263 local_irq_restore(flags);
266 static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
270 for_each_cpu(cpu, callmap)
271 ipi_send_msg_one(cpu, msg);
274 void smp_send_reschedule(int cpu)
276 ipi_send_msg_one(cpu, IPI_RESCHEDULE);
279 void smp_send_stop(void)
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);
287 void arch_send_call_function_single_ipi(int cpu)
289 ipi_send_msg_one(cpu, IPI_CALL_FUNC);
292 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
294 ipi_send_msg(mask, IPI_CALL_FUNC);
298 * ipi_cpu_stop - handle IPI from smp_send_stop()
300 static void ipi_cpu_stop(void)
305 static inline int __do_IPI(unsigned long msg)
315 generic_smp_call_function_interrupt();
330 * arch-common ISR to handle for inter-processor interrupts
331 * Has hooks for platform specific IPI
333 irqreturn_t do_IPI(int irq, void *dev_id)
335 unsigned long pending;
336 unsigned long __maybe_unused copy;
338 pr_debug("IPI [%ld] received on cpu %d\n",
339 *this_cpu_ptr(&ipi_data), smp_processor_id());
341 if (plat_smp_ops.ipi_clear)
342 plat_smp_ops.ipi_clear(irq);
345 * "dequeue" the msg corresponding to this IPI (and possibly other
346 * piggybacked msg from elided IPIs: see ipi_send_msg_one() above)
348 copy = pending = xchg(this_cpu_ptr(&ipi_data), 0);
351 unsigned long msg = __ffs(pending);
356 pr_info("IPI with bogus msg %ld in %ld\n", msg, copy);
357 pending &= ~(1U << msg);
364 * API called by platform code to hookup arch-common ISR to their IPI IRQ
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
370 static DEFINE_PER_CPU(int, ipi_dev);
372 int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq)
374 int *dev = per_cpu_ptr(&ipi_dev, cpu);
375 unsigned int virq = irq_find_mapping(NULL, hwirq);
378 panic("Cannot find virq for root domain and hwirq=%lu", hwirq);
380 /* Boot cpu calls request, all call enable */
384 rc = request_percpu_irq(virq, do_IPI, "IPI Interrupt", dev);
386 panic("Percpu IRQ request failed for %u\n", virq);
389 enable_percpu_irq(virq, 0);