From ea5804015c0ce67741eb4b156a071fb4f415345f Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Thu, 11 Oct 2007 23:46:09 +0100 Subject: [PATCH] [MIPS] Dyntick support for SMTC: The kernel currently only supports broadcasting of the timer interrupt from a single timer, not multicasting into two multicast groups of processors. So the implemented mechanism for SMTC works by broadcasting the cp0 compare interrupt on VPE 0 and ignoring it on any additional VPEs. Signed-off-by: Ralf Baechle --- arch/mips/Kconfig | 4 + arch/mips/kernel/smtc.c | 67 ++++++++-------- arch/mips/kernel/time.c | 111 +++++++++++++++++++++++---- arch/mips/mips-boards/generic/time.c | 1 - 4 files changed, 134 insertions(+), 49 deletions(-) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index ecce3aab198..d8c905840af 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -1368,6 +1368,7 @@ config MIPS_MT_SMTC depends on CPU_MIPS32_R2 #depends on CPU_MIPS64_R2 # once there is hardware ... depends on SYS_SUPPORTS_MULTITHREADING + select GENERIC_CLOCKEVENTS_BROADCAST select CPU_MIPSR2_IRQ_VI select CPU_MIPSR2_IRQ_EI select CPU_MIPSR2_SRS @@ -1537,6 +1538,9 @@ config CPU_HAS_SYNC depends on !CPU_R3000 default y +config GENERIC_CLOCKEVENTS_BROADCAST + bool + # # Use the generic interrupt handling code in kernel/irq/: # diff --git a/arch/mips/kernel/smtc.c b/arch/mips/kernel/smtc.c index 137183bba54..4d1ac9692dc 100644 --- a/arch/mips/kernel/smtc.c +++ b/arch/mips/kernel/smtc.c @@ -1,5 +1,6 @@ /* Copyright (C) 2004 Mips Technologies, Inc */ +#include #include #include #include @@ -62,7 +63,7 @@ asiduse smtc_live_asid[MAX_SMTC_TLBS][MAX_SMTC_ASIDS]; * Clock interrupt "latch" buffers, per "CPU" */ -unsigned int ipi_timer_latch[NR_CPUS]; +static atomic_t ipi_timer_latch[NR_CPUS]; /* * Number of InterProcessor Interupt (IPI) message buffers to allocate @@ -296,8 +297,10 @@ int __init mipsmt_build_cpu_map(int start_cpu_slot) __cpu_number_map[i] = i; __cpu_logical_map[i] = i; } +#ifdef CONFIG_MIPS_MT_FPAFF /* Initialize map of CPUs with FPUs */ cpus_clear(mt_fpu_cpumask); +#endif /* One of those TC's is the one booting, and not a secondary... */ printk("%i available secondary CPU TC(s)\n", i - 1); @@ -359,7 +362,7 @@ void mipsmt_prepare_cpus(void) IPIQ[i].head = IPIQ[i].tail = NULL; spin_lock_init(&IPIQ[i].lock); IPIQ[i].depth = 0; - ipi_timer_latch[i] = 0; + atomic_set(&ipi_timer_latch[i], 0); } /* cpu_data index starts at zero */ @@ -482,10 +485,12 @@ void mipsmt_prepare_cpus(void) /* Set up coprocessor affinity CPU mask(s) */ +#ifdef CONFIG_MIPS_MT_FPAFF for (tc = 0; tc < ntc; tc++) { if (cpu_data[tc].options & MIPS_CPU_FPU) cpu_set(tc, mt_fpu_cpumask); } +#endif /* set up ipi interrupts... */ @@ -702,7 +707,7 @@ static void smtc_ipi_qdump(void) * be done with the atomic.h primitives). And since this is * MIPS MT, we can assume that we have LL/SC. */ -static __inline__ int atomic_postincrement(unsigned int *pv) +static inline int atomic_postincrement(atomic_t *v) { unsigned long result; @@ -714,8 +719,8 @@ static __inline__ int atomic_postincrement(unsigned int *pv) " sc %1, %2 \n" " beqz %1, 1b \n" __WEAK_LLSC_MB - : "=&r" (result), "=&r" (temp), "=m" (*pv) - : "m" (*pv) + : "=&r" (result), "=&r" (temp), "=m" (v->counter) + : "m" (v->counter) : "memory"); return result; @@ -743,6 +748,8 @@ void smtc_send_ipi(int cpu, int type, unsigned int action) pipi->arg = (void *)action; pipi->dest = cpu; if (cpu_data[cpu].vpe_id != cpu_data[smp_processor_id()].vpe_id) { + if (type == SMTC_CLOCK_TICK) + atomic_inc(&ipi_timer_latch[cpu]); /* If not on same VPE, enqueue and send cross-VPE interupt */ smtc_ipi_nq(&IPIQ[cpu], pipi); LOCK_CORE_PRA(); @@ -784,6 +791,8 @@ void smtc_send_ipi(int cpu, int type, unsigned int action) } smtc_ipi_nq(&IPIQ[cpu], pipi); } else { + if (type == SMTC_CLOCK_TICK) + atomic_inc(&ipi_timer_latch[cpu]); post_direct_ipi(cpu, pipi); write_tc_c0_tchalt(0); UNLOCK_CORE_PRA(); @@ -801,6 +810,7 @@ static void post_direct_ipi(int cpu, struct smtc_ipi *pipi) unsigned long tcrestart; extern u32 kernelsp[NR_CPUS]; extern void __smtc_ipi_vector(void); +//printk("%s: on %d for %d\n", __func__, smp_processor_id(), cpu); /* Extract Status, EPC from halted TC */ tcstatus = read_tc_c0_tcstatus(); @@ -851,25 +861,31 @@ static void ipi_call_interrupt(void) smp_call_function_interrupt(); } +DECLARE_PER_CPU(struct clock_event_device, smtc_dummy_clockevent_device); + void ipi_decode(struct smtc_ipi *pipi) { + unsigned int cpu = smp_processor_id(); + struct clock_event_device *cd; void *arg_copy = pipi->arg; int type_copy = pipi->type; - int dest_copy = pipi->dest; + int ticks; smtc_ipi_nq(&freeIPIq, pipi); switch (type_copy) { case SMTC_CLOCK_TICK: irq_enter(); - kstat_this_cpu.irqs[MIPS_CPU_IRQ_BASE + cp0_compare_irq]++; - /* Invoke Clock "Interrupt" */ - ipi_timer_latch[dest_copy] = 0; -#ifdef CONFIG_SMTC_IDLE_HOOK_DEBUG - clock_hang_reported[dest_copy] = 0; -#endif /* CONFIG_SMTC_IDLE_HOOK_DEBUG */ - local_timer_interrupt(0, NULL); + kstat_this_cpu.irqs[MIPS_CPU_IRQ_BASE + 1]++; + cd = &per_cpu(smtc_dummy_clockevent_device, cpu); + ticks = atomic_read(&ipi_timer_latch[cpu]); + atomic_sub(ticks, &ipi_timer_latch[cpu]); + while (ticks) { + cd->event_handler(cd); + ticks--; + } irq_exit(); break; + case LINUX_SMP_IPI: switch ((int)arg_copy) { case SMP_RESCHEDULE_YOURSELF: @@ -920,25 +936,6 @@ void deferred_smtc_ipi(void) } } -/* - * Send clock tick to all TCs except the one executing the funtion - */ - -void smtc_timer_broadcast(void) -{ - int cpu; - int myTC = cpu_data[smp_processor_id()].tc_id; - int myVPE = cpu_data[smp_processor_id()].vpe_id; - - smtc_cpu_stats[smp_processor_id()].timerints++; - - for_each_online_cpu(cpu) { - if (cpu_data[cpu].vpe_id == myVPE && - cpu_data[cpu].tc_id != myTC) - smtc_send_ipi(cpu, SMTC_CLOCK_TICK, 0); - } -} - /* * Cross-VPE interrupts in the SMTC prototype use "software interrupts" * set via cross-VPE MTTR manipulation of the Cause register. It would be @@ -1180,11 +1177,11 @@ void smtc_idle_loop_hook(void) for (tc = 0; tc < NR_CPUS; tc++) { /* Don't check ourself - we'll dequeue IPIs just below */ if ((tc != smp_processor_id()) && - ipi_timer_latch[tc] > timerq_limit) { + atomic_read(&ipi_timer_latch[tc]) > timerq_limit) { if (clock_hang_reported[tc] == 0) { pdb_msg += sprintf(pdb_msg, "TC %d looks hung with timer latch at %d\n", - tc, ipi_timer_latch[tc]); + tc, atomic_read(&ipi_timer_latch[tc])); clock_hang_reported[tc]++; } } @@ -1225,7 +1222,7 @@ void smtc_soft_dump(void) smtc_ipi_qdump(); printk("Timer IPI Backlogs:\n"); for (i=0; i < NR_CPUS; i++) { - printk("%d: %d\n", i, ipi_timer_latch[i]); + printk("%d: %d\n", i, atomic_read(&ipi_timer_latch[i])); } printk("%d Recoveries of \"stolen\" FPU\n", atomic_read(&smtc_fpu_recoveries)); diff --git a/arch/mips/kernel/time.c b/arch/mips/kernel/time.c index 35988847c98..369a5f9ad26 100644 --- a/arch/mips/kernel/time.c +++ b/arch/mips/kernel/time.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -33,6 +34,7 @@ #include #include #include +#include #include #include @@ -230,12 +232,24 @@ static int mips_next_event(unsigned long delta, struct clock_event_device *evt) { unsigned int cnt; + int res; +#ifdef CONFIG_MIPS_MT_SMTC + { + unsigned long flags, vpflags; + local_irq_save(flags); + vpflags = dvpe(); +#endif cnt = read_c0_count(); cnt += delta; write_c0_compare(cnt); - - return ((long)(read_c0_count() - cnt ) > 0) ? -ETIME : 0; + res = ((long)(read_c0_count() - cnt ) > 0) ? -ETIME : 0; +#ifdef CONFIG_MIPS_MT_SMTC + evpe(vpflags); + local_irq_restore(flags); + } +#endif + return res; } static void mips_set_mode(enum clock_event_mode mode, @@ -244,9 +258,7 @@ static void mips_set_mode(enum clock_event_mode mode, /* Nothing to do ... */ } -struct clock_event_device mips_clockevent; - -static struct clock_event_device *global_cd[NR_CPUS]; +static DEFINE_PER_CPU(struct clock_event_device, mips_clockevent_device); static int cp0_timer_irq_installed; static irqreturn_t timer_interrupt(int irq, void *dev_id) @@ -271,7 +283,12 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id) */ if (!r2 || (read_c0_cause() & (1 << 30))) { c0_timer_ack(); - cd = global_cd[cpu]; +#ifdef CONFIG_MIPS_MT_SMTC + if (cpu_data[cpu].vpe_id) + goto out; + cpu = 0; +#endif + cd = &per_cpu(mips_clockevent_device, cpu); cd->event_handler(cd); } @@ -281,7 +298,11 @@ out: static struct irqaction timer_irqaction = { .handler = timer_interrupt, +#ifdef CONFIG_MIPS_MT_SMTC + .flags = IRQF_DISABLED, +#else .flags = IRQF_DISABLED | IRQF_PERCPU, +#endif .name = "timer", }; @@ -316,6 +337,60 @@ void __init __weak plat_timer_setup(struct irqaction *irq) { } +#ifdef CONFIG_MIPS_MT_SMTC +DEFINE_PER_CPU(struct clock_event_device, smtc_dummy_clockevent_device); + +static void smtc_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ +} + +int dummycnt[NR_CPUS]; + +static void mips_broadcast(cpumask_t mask) +{ + unsigned int cpu; + + for_each_cpu_mask(cpu, mask) + smtc_send_ipi(cpu, SMTC_CLOCK_TICK, 0); +} + +static void setup_smtc_dummy_clockevent_device(void) +{ + //uint64_t mips_freq = mips_hpt_^frequency; + unsigned int cpu = smp_processor_id(); + struct clock_event_device *cd; + + cd = &per_cpu(smtc_dummy_clockevent_device, cpu); + + cd->name = "SMTC"; + cd->features = CLOCK_EVT_FEAT_DUMMY; + + /* Calculate the min / max delta */ + cd->mult = 0; //div_sc((unsigned long) mips_freq, NSEC_PER_SEC, 32); + cd->shift = 0; //32; + cd->max_delta_ns = 0; //clockevent_delta2ns(0x7fffffff, cd); + cd->min_delta_ns = 0; //clockevent_delta2ns(0x30, cd); + + cd->rating = 200; + cd->irq = 17; //-1; +// if (cpu) +// cd->cpumask = CPU_MASK_ALL; // cpumask_of_cpu(cpu); +// else + cd->cpumask = cpumask_of_cpu(cpu); + + cd->set_mode = smtc_set_mode; + + cd->broadcast = mips_broadcast; + + clockevents_register_device(cd); +} +#endif + +static void mips_event_handler(struct clock_event_device *dev) +{ +} + void __cpuinit mips_clockevent_init(void) { uint64_t mips_freq = mips_hpt_frequency; @@ -326,12 +401,18 @@ void __cpuinit mips_clockevent_init(void) if (!cpu_has_counter) return; - if (cpu == 0) - cd = &mips_clockevent; - else - cd = kzalloc(sizeof(*cd), GFP_ATOMIC); - if (!cd) - return; /* We're probably roadkill ... */ +#ifdef CONFIG_MIPS_MT_SMTC + setup_smtc_dummy_clockevent_device(); + + /* + * On SMTC we only register VPE0's compare interrupt as clockevent + * device. + */ + if (cpu) + return; +#endif + + cd = &per_cpu(mips_clockevent_device, cpu); cd->name = "MIPS"; cd->features = CLOCK_EVT_FEAT_ONESHOT; @@ -344,11 +425,15 @@ void __cpuinit mips_clockevent_init(void) cd->rating = 300; cd->irq = irq; +#ifdef CONFIG_MIPS_MT_SMTC + cd->cpumask = CPU_MASK_ALL; +#else cd->cpumask = cpumask_of_cpu(cpu); +#endif cd->set_next_event = mips_next_event; cd->set_mode = mips_set_mode; + cd->event_handler = mips_event_handler; - global_cd[cpu] = cd; clockevents_register_device(cd); if (!cp0_timer_irq_installed) { diff --git a/arch/mips/mips-boards/generic/time.c b/arch/mips/mips-boards/generic/time.c index 2c8db3e0f4b..cf55ecd96bf 100644 --- a/arch/mips/mips-boards/generic/time.c +++ b/arch/mips/mips-boards/generic/time.c @@ -55,7 +55,6 @@ unsigned long cpu_khz; static int mips_cpu_timer_irq; extern int cp0_perfcount_irq; -extern void smtc_timer_broadcast(void); static void mips_timer_dispatch(void) { -- 2.41.1