/* * SMP support for BPA machines. * * Dave Engebretsen, Peter Bergner, and * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com * * Plus various changes from other IBM teams... * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #undef DEBUG #include <linux/kernel.h> #include <linux/module.h> #include <linux/sched.h> #include <linux/smp.h> #include <linux/interrupt.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/cache.h> #include <linux/err.h> #include <linux/sysdev.h> #include <linux/cpu.h> #include <asm/ptrace.h> #include <asm/atomic.h> #include <asm/irq.h> #include <asm/page.h> #include <asm/pgtable.h> #include <asm/io.h> #include <asm/prom.h> #include <asm/smp.h> #include <asm/paca.h> #include <asm/time.h> #include <asm/machdep.h> #include <asm/cputable.h> #include <asm/firmware.h> #include <asm/system.h> #include <asm/rtas.h> #include "interrupt.h" #ifdef DEBUG #define DBG(fmt...) udbg_printf(fmt) #else #define DBG(fmt...) #endif /* * The primary thread of each non-boot processor is recorded here before * smp init. */ static cpumask_t of_spin_map; extern void generic_secondary_smp_init(unsigned long); /** * smp_startup_cpu() - start the given cpu * * At boot time, there is nothing to do for primary threads which were * started from Open Firmware. For anything else, call RTAS with the * appropriate start location. * * Returns: * 0 - failure * 1 - success */ static inline int __devinit smp_startup_cpu(unsigned int lcpu) { int status; unsigned long start_here = __pa((u32)*((unsigned long *) generic_secondary_smp_init)); unsigned int pcpu; int start_cpu; if (cpu_isset(lcpu, of_spin_map)) /* Already started by OF and sitting in spin loop */ return 1; pcpu = get_hard_smp_processor_id(lcpu); /* Fixup atomic count: it exited inside IRQ handler. */ task_thread_info(paca[lcpu].__current)->preempt_count = 0; /* * If the RTAS start-cpu token does not exist then presume the * cpu is already spinning. */ start_cpu = rtas_token("start-cpu"); if (start_cpu == RTAS_UNKNOWN_SERVICE) return 1; status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, lcpu); if (status != 0) { printk(KERN_ERR "start-cpu failed: %i\n", status); return 0; } return 1; } static void smp_iic_message_pass(int target, int msg) { unsigned int i; if (target < NR_CPUS) { iic_cause_IPI(target, msg); } else { for_each_online_cpu(i) { if (target == MSG_ALL_BUT_SELF && i == smp_processor_id()) continue; iic_cause_IPI(i, msg); } } } static int __init smp_iic_probe(void) { iic_request_IPIs(); return cpus_weight(cpu_possible_map); } static void __devinit smp_iic_setup_cpu(int cpu) { if (cpu != boot_cpuid) iic_setup_cpu(); } static DEFINE_SPINLOCK(timebase_lock); static unsigned long timebase = 0; static void __devinit cell_give_timebase(void) { spin_lock(&timebase_lock); rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL); timebase = get_tb(); spin_unlock(&timebase_lock); while (timebase) barrier(); rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL); } static void __devinit cell_take_timebase(void) { while (!timebase) barrier(); spin_lock(&timebase_lock); set_tb(timebase >> 32, timebase & 0xffffffff); timebase = 0; spin_unlock(&timebase_lock); } static void __devinit smp_cell_kick_cpu(int nr) { BUG_ON(nr < 0 || nr >= NR_CPUS); if (!smp_startup_cpu(nr)) return; /* * The processor is currently spinning, waiting for the * cpu_start field to become non-zero After we set cpu_start, * the processor will continue on to secondary_start */ paca[nr].cpu_start = 1; } static int smp_cell_cpu_bootable(unsigned int nr) { /* Special case - we inhibit secondary thread startup * during boot if the user requests it. Odd-numbered * cpus are assumed to be secondary threads. */ if (system_state < SYSTEM_RUNNING && cpu_has_feature(CPU_FTR_SMT) && !smt_enabled_at_boot && nr % 2 != 0) return 0; return 1; } static struct smp_ops_t bpa_iic_smp_ops = { .message_pass = smp_iic_message_pass, .probe = smp_iic_probe, .kick_cpu = smp_cell_kick_cpu, .setup_cpu = smp_iic_setup_cpu, .cpu_bootable = smp_cell_cpu_bootable, }; /* This is called very early */ void __init smp_init_cell(void) { int i; DBG(" -> smp_init_cell()\n"); smp_ops = &bpa_iic_smp_ops; /* Mark threads which are still spinning in hold loops. */ if (cpu_has_feature(CPU_FTR_SMT)) { for_each_present_cpu(i) { if (i % 2 == 0) /* * Even-numbered logical cpus correspond to * primary threads. */ cpu_set(i, of_spin_map); } } else { of_spin_map = cpu_present_map; } cpu_clear(boot_cpuid, of_spin_map); /* Non-lpar has additional take/give timebase */ if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) { smp_ops->give_timebase = cell_give_timebase; smp_ops->take_timebase = cell_take_timebase; } DBG(" <- smp_init_cell()\n"); }