diff options
Diffstat (limited to 'arch/powerpc/platforms/cell/smp.c')
| -rw-r--r-- | arch/powerpc/platforms/cell/smp.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/cell/smp.c b/arch/powerpc/platforms/cell/smp.c new file mode 100644 index 00000000000..de96eadf419 --- /dev/null +++ b/arch/powerpc/platforms/cell/smp.c @@ -0,0 +1,230 @@ +/* + * 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/config.h> +#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 pSeries_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 *) + pSeries_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. */ + paca[lcpu].__current->thread_info->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"); +} |