diff options
Diffstat (limited to 'arch/arc/kernel/smp.c')
| -rw-r--r-- | arch/arc/kernel/smp.c | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c new file mode 100644 index 00000000000..3af3e06dcf0 --- /dev/null +++ b/arch/arc/kernel/smp.c @@ -0,0 +1,332 @@ +/* + * 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> +#include <asm/mach_desc.h> + +arch_spinlock_t smp_atomic_ops_lock = __ARCH_SPIN_LOCK_UNLOCKED; +arch_spinlock_t smp_bitops_lock = __ARCH_SPIN_LOCK_UNLOCKED; + +struct plat_smp_ops plat_smp_ops; + +/* 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"); +} + +const char *arc_platform_smp_cpuinfo(void) +{ + return plat_smp_ops.info; +} + +/* + * 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); + + if (machine_desc->init_smp) + machine_desc->init_smp(smp_processor_id()); + + 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); + + if (plat_smp_ops.cpu_kick) + plat_smp_ops.cpu_kick(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 */ + if (plat_smp_ops.ipi_send) + plat_smp_ops.ipi_send((void *)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; + + if (plat_smp_ops.ipi_clear) + plat_smp_ops.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); +} |