diff options
Diffstat (limited to 'arch/powerpc/kernel/time.c')
| -rw-r--r-- | arch/powerpc/kernel/time.c | 67 |
1 files changed, 59 insertions, 8 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 3ed9a5a21d77..6b4d01d1ccf0 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -96,7 +96,8 @@ static struct clocksource clocksource_timebase = { .read = timebase_read, }; -#define DECREMENTER_MAX 0x7fffffff +#define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF +u64 decrementer_max = DECREMENTER_DEFAULT_MAX; static int decrementer_set_next_event(unsigned long evt, struct clock_event_device *dev); @@ -504,8 +505,8 @@ static void __timer_interrupt(void) __this_cpu_inc(irq_stat.timer_irqs_event); } else { now = *next_tb - now; - if (now <= DECREMENTER_MAX) - set_dec((int)now); + if (now <= decrementer_max) + set_dec(now); /* We may have raced with new irq work */ if (test_irq_work_pending()) set_dec(1); @@ -535,7 +536,7 @@ void timer_interrupt(struct pt_regs * regs) /* Ensure a positive value is written to the decrementer, or else * some CPUs will continue to take decrementer exceptions. */ - set_dec(DECREMENTER_MAX); + set_dec(decrementer_max); /* Some implementations of hotplug will get timer interrupts while * offline, just ignore these and we also need to set @@ -583,9 +584,9 @@ static void generic_suspend_disable_irqs(void) * with suspending. */ - set_dec(DECREMENTER_MAX); + set_dec(decrementer_max); local_irq_disable(); - set_dec(DECREMENTER_MAX); + set_dec(decrementer_max); } static void generic_suspend_enable_irqs(void) @@ -866,7 +867,7 @@ static int decrementer_set_next_event(unsigned long evt, static int decrementer_shutdown(struct clock_event_device *dev) { - decrementer_set_next_event(DECREMENTER_MAX, dev); + decrementer_set_next_event(decrementer_max, dev); return 0; } @@ -892,6 +893,49 @@ static void register_decrementer_clockevent(int cpu) clockevents_register_device(dec); } +static void enable_large_decrementer(void) +{ + if (!cpu_has_feature(CPU_FTR_ARCH_300)) + return; + + if (decrementer_max <= DECREMENTER_DEFAULT_MAX) + return; + + /* + * If we're running as the hypervisor we need to enable the LD manually + * otherwise firmware should have done it for us. + */ + if (cpu_has_feature(CPU_FTR_HVMODE)) + mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD); +} + +static void __init set_decrementer_max(void) +{ + struct device_node *cpu; + u32 bits = 32; + + /* Prior to ISAv3 the decrementer is always 32 bit */ + if (!cpu_has_feature(CPU_FTR_ARCH_300)) + return; + + cpu = of_find_node_by_type(NULL, "cpu"); + + if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) { + if (bits > 64 || bits < 32) { + pr_warn("time_init: firmware supplied invalid ibm,dec-bits"); + bits = 32; + } + + /* calculate the signed maximum given this many bits */ + decrementer_max = (1ul << (bits - 1)) - 1; + } + + of_node_put(cpu); + + pr_info("time_init: %u bit decrementer (max: %llx)\n", + bits, decrementer_max); +} + static void __init init_decrementer_clockevent(void) { int cpu = smp_processor_id(); @@ -899,7 +943,7 @@ static void __init init_decrementer_clockevent(void) clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); decrementer_clockevent.max_delta_ns = - clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); + clockevent_delta2ns(decrementer_max, &decrementer_clockevent); decrementer_clockevent.min_delta_ns = clockevent_delta2ns(2, &decrementer_clockevent); @@ -908,6 +952,9 @@ static void __init init_decrementer_clockevent(void) void secondary_cpu_time_init(void) { + /* Enable and test the large decrementer for this cpu */ + enable_large_decrementer(); + /* Start the decrementer on CPUs that have manual control * such as BookE */ @@ -973,6 +1020,10 @@ void __init time_init(void) vdso_data->tb_update_count = 0; vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; + /* initialise and enable the large decrementer (if we have one) */ + set_decrementer_max(); + enable_large_decrementer(); + /* Start the decrementer on CPUs that have manual control * such as BookE */ |