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[linux/fpc-iii.git] / arch / hexagon / kernel / smp.c
blob0e364ca4319811b34ad71f213cb226e819ba7e9e
1 /*
2 * SMP support for Hexagon
4 * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18 * 02110-1301, USA.
21 #include <linux/err.h>
22 #include <linux/errno.h>
23 #include <linux/kernel.h>
24 #include <linux/init.h>
25 #include <linux/interrupt.h>
26 #include <linux/module.h>
27 #include <linux/percpu.h>
28 #include <linux/sched.h>
29 #include <linux/smp.h>
30 #include <linux/spinlock.h>
31 #include <linux/cpu.h>
33 #include <asm/time.h> /* timer_interrupt */
34 #include <asm/hexagon_vm.h>
36 #define BASE_IPI_IRQ 26
39 * cpu_possible_mask needs to be filled out prior to setup_per_cpu_areas
40 * (which is prior to any of our smp_prepare_cpu crap), in order to set
41 * up the... per_cpu areas.
44 struct ipi_data {
45 unsigned long bits;
48 static DEFINE_PER_CPU(struct ipi_data, ipi_data);
50 static inline void __handle_ipi(unsigned long *ops, struct ipi_data *ipi,
51 int cpu)
53 unsigned long msg = 0;
54 do {
55 msg = find_next_bit(ops, BITS_PER_LONG, msg+1);
57 switch (msg) {
59 case IPI_TIMER:
60 ipi_timer();
61 break;
63 case IPI_CALL_FUNC:
64 generic_smp_call_function_interrupt();
65 break;
67 case IPI_CALL_FUNC_SINGLE:
68 generic_smp_call_function_single_interrupt();
69 break;
71 case IPI_CPU_STOP:
73 * call vmstop()
75 __vmstop();
76 break;
78 case IPI_RESCHEDULE:
79 scheduler_ipi();
80 break;
82 } while (msg < BITS_PER_LONG);
85 /* Used for IPI call from other CPU's to unmask int */
86 void smp_vm_unmask_irq(void *info)
88 __vmintop_locen((long) info);
93 * This is based on Alpha's IPI stuff.
94 * Supposed to take (int, void*) as args now.
95 * Specifically, first arg is irq, second is the irq_desc.
98 irqreturn_t handle_ipi(int irq, void *desc)
100 int cpu = smp_processor_id();
101 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
102 unsigned long ops;
104 while ((ops = xchg(&ipi->bits, 0)) != 0)
105 __handle_ipi(&ops, ipi, cpu);
106 return IRQ_HANDLED;
109 void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg)
111 unsigned long flags;
112 unsigned long cpu;
113 unsigned long retval;
115 local_irq_save(flags);
117 for_each_cpu(cpu, cpumask) {
118 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
120 set_bit(msg, &ipi->bits);
121 /* Possible barrier here */
122 retval = __vmintop_post(BASE_IPI_IRQ+cpu);
124 if (retval != 0) {
125 printk(KERN_ERR "interrupt %ld not configured?\n",
126 BASE_IPI_IRQ+cpu);
130 local_irq_restore(flags);
133 static struct irqaction ipi_intdesc = {
134 .handler = handle_ipi,
135 .flags = IRQF_TRIGGER_RISING,
136 .name = "ipi_handler"
139 void __init smp_prepare_boot_cpu(void)
144 * interrupts should already be disabled from the VM
145 * SP should already be correct; need to set THREADINFO_REG
146 * to point to current thread info
149 void __cpuinit start_secondary(void)
151 unsigned int cpu;
152 unsigned long thread_ptr;
154 /* Calculate thread_info pointer from stack pointer */
155 __asm__ __volatile__(
156 "%0 = SP;\n"
157 : "=r" (thread_ptr)
160 thread_ptr = thread_ptr & ~(THREAD_SIZE-1);
162 __asm__ __volatile__(
163 QUOTED_THREADINFO_REG " = %0;\n"
165 : "r" (thread_ptr)
168 /* Set the memory struct */
169 atomic_inc(&init_mm.mm_count);
170 current->active_mm = &init_mm;
172 cpu = smp_processor_id();
174 setup_irq(BASE_IPI_IRQ + cpu, &ipi_intdesc);
176 /* Register the clock_event dummy */
177 setup_percpu_clockdev();
179 printk(KERN_INFO "%s cpu %d\n", __func__, current_thread_info()->cpu);
181 notify_cpu_starting(cpu);
183 set_cpu_online(cpu, true);
185 local_irq_enable();
187 cpu_startup_entry(CPUHP_ONLINE);
192 * called once for each present cpu
193 * apparently starts up the CPU and then
194 * maintains control until "cpu_online(cpu)" is set.
197 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
199 struct thread_info *thread = (struct thread_info *)idle->stack;
200 void *stack_start;
202 thread->cpu = cpu;
204 /* Boot to the head. */
205 stack_start = ((void *) thread) + THREAD_SIZE;
206 __vmstart(start_secondary, stack_start);
208 while (!cpu_online(cpu))
209 barrier();
211 return 0;
214 void __init smp_cpus_done(unsigned int max_cpus)
218 void __init smp_prepare_cpus(unsigned int max_cpus)
220 int i;
223 * should eventually have some sort of machine
224 * descriptor that has this stuff
227 /* Right now, let's just fake it. */
228 for (i = 0; i < max_cpus; i++)
229 set_cpu_present(i, true);
231 /* Also need to register the interrupts for IPI */
232 if (max_cpus > 1)
233 setup_irq(BASE_IPI_IRQ, &ipi_intdesc);
236 void smp_send_reschedule(int cpu)
238 send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
241 void smp_send_stop(void)
243 struct cpumask targets;
244 cpumask_copy(&targets, cpu_online_mask);
245 cpumask_clear_cpu(smp_processor_id(), &targets);
246 send_ipi(&targets, IPI_CPU_STOP);
249 void arch_send_call_function_single_ipi(int cpu)
251 send_ipi(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
254 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
256 send_ipi(mask, IPI_CALL_FUNC);
259 int setup_profiling_timer(unsigned int multiplier)
261 return -EINVAL;
264 void smp_start_cpus(void)
266 int i;
268 for (i = 0; i < NR_CPUS; i++)
269 set_cpu_possible(i, true);