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.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 static void arc_default_smp_cpu_kick(int cpu, unsigned long pc)
99 void arc_platform_smp_wait_to_boot(int cpu)
101 while (wake_flag != cpu)
105 __asm__ __volatile__("j @first_lines_of_secondary \n");
109 const char *arc_platform_smp_cpuinfo(void)
111 return plat_smp_ops.info ? : "";
115 * The very first "C" code executed by secondary
116 * Called from asm stub in head.S
117 * "current"/R25 already setup by low level boot code
119 void start_kernel_secondary(void)
121 struct mm_struct *mm = &init_mm;
122 unsigned int cpu = smp_processor_id();
124 /* MMU, Caches, Vector Table, Interrupts etc */
127 atomic_inc(&mm->mm_users);
128 atomic_inc(&mm->mm_count);
129 current->active_mm = mm;
130 cpumask_set_cpu(cpu, mm_cpumask(mm));
132 /* Some SMP H/w setup - for each cpu */
133 if (plat_smp_ops.init_per_cpu)
134 plat_smp_ops.init_per_cpu(cpu);
136 if (machine_desc->init_per_cpu)
137 machine_desc->init_per_cpu(cpu);
139 notify_cpu_starting(cpu);
140 set_cpu_online(cpu, true);
142 pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu);
146 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
150 * Called from kernel_init( ) -> smp_init( ) - for each CPU
152 * At this point, Secondary Processor is "HALT"ed:
153 * -It booted, but was halted in head.S
154 * -It was configured to halt-on-reset
155 * So need to wake it up.
157 * Essential requirements being where to run from (PC) and stack (SP)
159 int __cpu_up(unsigned int cpu, struct task_struct *idle)
161 unsigned long wait_till;
163 secondary_idle_tsk = idle;
165 pr_info("Idle Task [%d] %p", cpu, idle);
166 pr_info("Trying to bring up CPU%u ...\n", cpu);
168 if (plat_smp_ops.cpu_kick)
169 plat_smp_ops.cpu_kick(cpu,
170 (unsigned long)first_lines_of_secondary);
172 arc_default_smp_cpu_kick(cpu, (unsigned long)NULL);
174 /* wait for 1 sec after kicking the secondary */
175 wait_till = jiffies + HZ;
176 while (time_before(jiffies, wait_till)) {
181 if (!cpu_online(cpu)) {
182 pr_info("Timeout: CPU%u FAILED to comeup !!!\n", cpu);
186 secondary_idle_tsk = NULL;
194 int setup_profiling_timer(unsigned int multiplier)
199 /*****************************************************************************/
200 /* Inter Processor Interrupt Handling */
201 /*****************************************************************************/
211 * In arches with IRQ for each msg type (above), receiver can use IRQ-id to
212 * figure out what msg was sent. For those which don't (ARC has dedicated IPI
213 * IRQ), the msg-type needs to be conveyed via per-cpu data
216 static DEFINE_PER_CPU(unsigned long, ipi_data);
218 static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg)
220 unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu);
221 unsigned long old, new;
224 pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu);
226 local_irq_save(flags);
229 * Atomically write new msg bit (in case others are writing too),
230 * and read back old value
233 new = old = ACCESS_ONCE(*ipi_data_ptr);
235 } while (cmpxchg(ipi_data_ptr, old, new) != old);
238 * Call the platform specific IPI kick function, but avoid if possible:
239 * Only do so if there's no pending msg from other concurrent sender(s).
240 * Otherwise, recevier will see this msg as well when it takes the
241 * IPI corresponding to that msg. This is true, even if it is already in
242 * IPI handler, because !@old means it has not yet dequeued the msg(s)
243 * so @new msg can be a free-loader
245 if (plat_smp_ops.ipi_send && !old)
246 plat_smp_ops.ipi_send(cpu);
248 local_irq_restore(flags);
251 static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
255 for_each_cpu(cpu, callmap)
256 ipi_send_msg_one(cpu, msg);
259 void smp_send_reschedule(int cpu)
261 ipi_send_msg_one(cpu, IPI_RESCHEDULE);
264 void smp_send_stop(void)
266 struct cpumask targets;
267 cpumask_copy(&targets, cpu_online_mask);
268 cpumask_clear_cpu(smp_processor_id(), &targets);
269 ipi_send_msg(&targets, IPI_CPU_STOP);
272 void arch_send_call_function_single_ipi(int cpu)
274 ipi_send_msg_one(cpu, IPI_CALL_FUNC);
277 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
279 ipi_send_msg(mask, IPI_CALL_FUNC);
283 * ipi_cpu_stop - handle IPI from smp_send_stop()
285 static void ipi_cpu_stop(void)
290 static inline int __do_IPI(unsigned long msg)
300 generic_smp_call_function_interrupt();
315 * arch-common ISR to handle for inter-processor interrupts
316 * Has hooks for platform specific IPI
318 irqreturn_t do_IPI(int irq, void *dev_id)
320 unsigned long pending;
321 unsigned long __maybe_unused copy;
323 pr_debug("IPI [%ld] received on cpu %d\n",
324 *this_cpu_ptr(&ipi_data), smp_processor_id());
326 if (plat_smp_ops.ipi_clear)
327 plat_smp_ops.ipi_clear(irq);
330 * "dequeue" the msg corresponding to this IPI (and possibly other
331 * piggybacked msg from elided IPIs: see ipi_send_msg_one() above)
333 copy = pending = xchg(this_cpu_ptr(&ipi_data), 0);
336 unsigned long msg = __ffs(pending);
341 pr_info("IPI with bogus msg %ld in %ld\n", msg, copy);
342 pending &= ~(1U << msg);
349 * API called by platform code to hookup arch-common ISR to their IPI IRQ
351 * Note: If IPI is provided by platform (vs. say ARC MCIP), their intc setup/map
352 * function needs to call call irq_set_percpu_devid() for IPI IRQ, otherwise
353 * request_percpu_irq() below will fail
355 static DEFINE_PER_CPU(int, ipi_dev);
357 int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq)
359 int *dev = per_cpu_ptr(&ipi_dev, cpu);
360 unsigned int virq = irq_find_mapping(NULL, hwirq);
363 panic("Cannot find virq for root domain and hwirq=%lu", hwirq);
365 /* Boot cpu calls request, all call enable */
369 rc = request_percpu_irq(virq, do_IPI, "IPI Interrupt", dev);
371 panic("Percpu IRQ request failed for %u\n", virq);
374 enable_percpu_irq(virq, 0);