/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* RajeshwarR: Dec 11, 2007
* -- Added support for Inter Processor Interrupts
*
* Vineetg: Nov 1st, 2007
* -- Initial Write (Borrowed heavily from ARM)
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/profile.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/mm.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/atomic.h>
#include <linux/percpu.h>
#include <linux/cpumask.h>
#include <linux/spinlock_types.h>
#include <linux/reboot.h>
#include <asm/processor.h>
#include <asm/setup.h>
arch_spinlock_t smp_atomic_ops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
arch_spinlock_t smp_bitops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
/* XXX: per cpu ? Only needed once in early seconday boot */
struct task_struct *secondary_idle_tsk;
/* Called from start_kernel */
void __init smp_prepare_boot_cpu(void)
{
}
/*
* Initialise the CPU possible map early - this describes the CPUs
* which may be present or become present in the system.
*/
void __init smp_init_cpus(void)
{
unsigned int i;
for (i = 0; i < NR_CPUS; i++)
set_cpu_possible(i, true);
}
/* called from init ( ) => process 1 */
void __init smp_prepare_cpus(unsigned int max_cpus)
{
int i;
/*
* Initialise the present map, which describes the set of CPUs
* actually populated at the present time.
*/
for (i = 0; i < max_cpus; i++)
set_cpu_present(i, true);
}
void __init smp_cpus_done(unsigned int max_cpus)
{
}
/*
* After power-up, a non Master CPU needs to wait for Master to kick start it
*
* The default implementation halts
*
* This relies on platform specific support allowing Master to directly set
* this CPU's PC (to be @first_lines_of_secondary() and kick start it.
*
* In lack of such h/w assist, platforms can override this function
* - make this function busy-spin on a token, eventually set by Master
* (from arc_platform_smp_wakeup_cpu())
* - Once token is available, jump to @first_lines_of_secondary
* (using inline asm).
*
* Alert: can NOT use stack here as it has not been determined/setup for CPU.
* If it turns out to be elaborate, it's better to code it in assembly
*
*/
void __attribute__((weak)) arc_platform_smp_wait_to_boot(int cpu)
{
/*
* As a hack for debugging - since debugger will single-step over the
* FLAG insn - wrap the halt itself it in a self loop
*/
__asm__ __volatile__(
"1: \n"
" flag 1 \n"
" b 1b \n");
}
/*
* The very first "C" code executed by secondary
* Called from asm stub in head.S
* "current"/R25 already setup by low level boot code
*/
void __cpuinit start_kernel_secondary(void)
{
struct mm_struct *mm = &init_mm;
unsigned int cpu = smp_processor_id();
/* MMU, Caches, Vector Table, Interrupts etc */
setup_processor();
atomic_inc(&mm->mm_users);
atomic_inc(&mm->mm_count);
current->active_mm = mm;
notify_cpu_starting(cpu);
set_cpu_online(cpu, true);
pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu);
arc_platform_smp_init_cpu();
arc_local_timer_setup(cpu);
local_irq_enable();
preempt_disable();
cpu_idle();
}
/*
* Called from kernel_init( ) -> smp_init( ) - for each CPU
*
* At this point, Secondary Processor is "HALT"ed:
* -It booted, but was halted in head.S
* -It was configured to halt-on-reset
* So need to wake it up.
*
* Essential requirements being where to run from (PC) and stack (SP)
*/
int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
{
unsigned long wait_till;
secondary_idle_tsk = idle;
pr_info("Idle Task [%d] %p", cpu, idle);
pr_info("Trying to bring up CPU%u ...\n", cpu);
arc_platform_smp_wakeup_cpu(cpu,
(unsigned long)first_lines_of_secondary);
/* wait for 1 sec after kicking the secondary */
wait_till = jiffies + HZ;
while (time_before(jiffies, wait_till)) {
if (cpu_online(cpu))
break;
}
if (!cpu_online(cpu)) {
pr_info("Timeout: CPU%u FAILED to comeup !!!\n", cpu);
return -1;
}
secondary_idle_tsk = NULL;
return 0;
}
/*
* not supported here
*/
int __init setup_profiling_timer(unsigned int multiplier)
{
return -EINVAL;
}
/*****************************************************************************/
/* Inter Processor Interrupt Handling */
/*****************************************************************************/
/*
* structures for inter-processor calls
* A Collection of single bit ipi messages
*
*/
/*
* TODO_rajesh investigate tlb message types.
* IPI Timer not needed because each ARC has an individual Interrupting Timer
*/
enum ipi_msg_type {
IPI_NOP = 0,
IPI_RESCHEDULE = 1,
IPI_CALL_FUNC,
IPI_CALL_FUNC_SINGLE,
IPI_CPU_STOP
};
struct ipi_data {
unsigned long bits;
};
static DEFINE_PER_CPU(struct ipi_data, ipi_data);
static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
{
unsigned long flags;
unsigned int cpu;
local_irq_save(flags);
for_each_cpu(cpu, callmap) {
struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
set_bit(msg, &ipi->bits);
}
/* Call the platform specific cross-CPU call function */
arc_platform_ipi_send(callmap);
local_irq_restore(flags);
}
void smp_send_reschedule(int cpu)
{
ipi_send_msg(cpumask_of(cpu), IPI_RESCHEDULE);
}
void smp_send_stop(void)
{
struct cpumask targets;
cpumask_copy(&targets, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &targets);
ipi_send_msg(&targets, IPI_CPU_STOP);
}
void arch_send_call_function_single_ipi(int cpu)
{
ipi_send_msg(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
}
void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
ipi_send_msg(mask, IPI_CALL_FUNC);
}
/*
* ipi_cpu_stop - handle IPI from smp_send_stop()
*/
static void ipi_cpu_stop(unsigned int cpu)
{
machine_halt();
}
static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi, int cpu)
{
unsigned long msg = 0;
do {
msg = find_next_bit(ops, BITS_PER_LONG, msg+1);
switch (msg) {
case IPI_RESCHEDULE:
scheduler_ipi();
break;
case IPI_CALL_FUNC:
generic_smp_call_function_interrupt();
break;
case IPI_CALL_FUNC_SINGLE:
generic_smp_call_function_single_interrupt();
break;
case IPI_CPU_STOP:
ipi_cpu_stop(cpu);
break;
}
} while (msg < BITS_PER_LONG);
}
/*
* arch-common ISR to handle for inter-processor interrupts
* Has hooks for platform specific IPI
*/
irqreturn_t do_IPI(int irq, void *dev_id)
{
int cpu = smp_processor_id();
struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
unsigned long ops;
arc_platform_ipi_clear(cpu, irq);
/*
* XXX: is this loop really needed
* And do we need to move ipi_clean inside
*/
while ((ops = xchg(&ipi->bits, 0)) != 0)
__do_IPI(&ops, ipi, cpu);
return IRQ_HANDLED;
}
/*
* API called by platform code to hookup arch-common ISR to their IPI IRQ
*/
static DEFINE_PER_CPU(int, ipi_dev);
int smp_ipi_irq_setup(int cpu, int irq)
{
int *dev_id = &per_cpu(ipi_dev, smp_processor_id());
return request_percpu_irq(irq, do_IPI, "IPI Interrupt", dev_id);
}
