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 MIPS_MT
Includes a loader for loading an elf relocatable object
onto another VPE and running it.
-config MIPS_MT_SMTC_INSTANT_REPLAY
- bool "Low-latency Dispatch of Deferred SMTC IPIs"
- depends on MIPS_MT_SMTC && !PREEMPT
- default y
- help
- SMTC pseudo-interrupts between TCs are deferred and queued
- if the target TC is interrupt-inhibited (IXMT). In the first
- SMTC prototypes, these queued IPIs were serviced on return
- to user mode, or on entry into the kernel idle loop. The
- INSTANT_REPLAY option dispatches them as part of local_irq_restore()
- processing, which adds runtime overhead (hence the option to turn
- it off), but ensures that IPIs are handled promptly even under
- heavy I/O interrupt load.
-
config MIPS_MT_SMTC_IM_BACKSTOP
bool "Use per-TC register bits as backstop for inhibited IM bits"
depends on MIPS_MT_SMTC
- default y
+ default n
help
To support multiple TC microthreads acting as "CPUs" within
a VPE, VPE-wide interrupt mask bits must be specially manipulated
during interrupt handling. To support legacy drivers and interrupt
controller management code, SMTC has a "backstop" to track and
if necessary restore the interrupt mask. This has some performance
- impact on interrupt service overhead. Disable it only if you know
- what you are doing.
+ impact on interrupt service overhead.
config MIPS_MT_SMTC_IRQAFF
bool "Support IRQ affinity API"
Enables SMP IRQ affinity API (/proc/irq/*/smp_affinity, etc.)
for SMTC Linux kernel. Requires platform support, of which
an example can be found in the MIPS kernel i8259 and Malta
- platform code. It is recommended that MIPS_MT_SMTC_INSTANT_REPLAY
- be enabled if MIPS_MT_SMTC_IRQAFF is used. Adds overhead to
- interrupt dispatch, and should be used only if you know what
- you are doing.
+ platform code. Adds some overhead to interrupt dispatch, and
+ should be used only if you know what you are doing.
config MIPS_VPE_LOADER_TOM
bool "Load VPE program into memory hidden from linux"
obj-$(CONFIG_CEVT_BCM1480) += cevt-bcm1480.o
obj-$(CONFIG_CEVT_R4K) += cevt-r4k.o
+obj-$(CONFIG_MIPS_MT_SMTC) += cevt-smtc.o
obj-$(CONFIG_CEVT_DS1287) += cevt-ds1287.o
obj-$(CONFIG_CEVT_GT641XX) += cevt-gt641xx.o
obj-$(CONFIG_CEVT_SB1250) += cevt-sb1250.o
#include <asm/smtc_ipi.h>
#include <asm/time.h>
+#include <asm/cevt-r4k.h>
+
+/*
+ * The SMTC Kernel for the 34K, 1004K, et. al. replaces several
+ * of these routines with SMTC-specific variants.
+ */
+
+#ifndef CONFIG_MIPS_MT_SMTC
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);
res = ((int)(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,
- struct clock_event_device *evt)
+#endif /* CONFIG_MIPS_MT_SMTC */
+
+void mips_set_clock_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
{
/* Nothing to do ... */
}
-static DEFINE_PER_CPU(struct clock_event_device, mips_clockevent_device);
-static int cp0_timer_irq_installed;
+DEFINE_PER_CPU(struct clock_event_device, mips_clockevent_device);
+int cp0_timer_irq_installed;
-/*
- * Timer ack for an R4k-compatible timer of a known frequency.
- */
-static void c0_timer_ack(void)
-{
- write_c0_compare(read_c0_compare());
-}
+#ifndef CONFIG_MIPS_MT_SMTC
-/*
- * Possibly handle a performance counter interrupt.
- * Return true if the timer interrupt should not be checked
- */
-static inline int handle_perf_irq(int r2)
-{
- /*
- * The performance counter overflow interrupt may be shared with the
- * timer interrupt (cp0_perfcount_irq < 0). If it is and a
- * performance counter has overflowed (perf_irq() == IRQ_HANDLED)
- * and we can't reliably determine if a counter interrupt has also
- * happened (!r2) then don't check for a timer interrupt.
- */
- return (cp0_perfcount_irq < 0) &&
- perf_irq() == IRQ_HANDLED &&
- !r2;
-}
-
-static irqreturn_t c0_compare_interrupt(int irq, void *dev_id)
+irqreturn_t c0_compare_interrupt(int irq, void *dev_id)
{
const int r2 = cpu_has_mips_r2;
struct clock_event_device *cd;
* interrupt. Being the paranoiacs we are we check anyway.
*/
if (!r2 || (read_c0_cause() & (1 << 30))) {
- c0_timer_ack();
-#ifdef CONFIG_MIPS_MT_SMTC
- if (cpu_data[cpu].vpe_id)
- goto out;
- cpu = 0;
-#endif
+ /* Clear Count/Compare Interrupt */
+ write_c0_compare(read_c0_compare());
cd = &per_cpu(mips_clockevent_device, cpu);
cd->event_handler(cd);
}
return IRQ_HANDLED;
}
-static struct irqaction c0_compare_irqaction = {
+#endif /* Not CONFIG_MIPS_MT_SMTC */
+
+struct irqaction c0_compare_irqaction = {
.handler = c0_compare_interrupt,
-#ifdef CONFIG_MIPS_MT_SMTC
- .flags = IRQF_DISABLED,
-#else
.flags = IRQF_DISABLED | IRQF_PERCPU,
-#endif
.name = "timer",
};
-#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)
-{
-}
-
-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 mips_event_handler(struct clock_event_device *dev)
{
}
return (read_c0_cause() >> cp0_compare_irq) & 0x100;
}
-static int c0_compare_int_usable(void)
+/*
+ * Compare interrupt can be routed and latched outside the core,
+ * so a single execution hazard barrier may not be enough to give
+ * it time to clear as seen in the Cause register. 4 time the
+ * pipeline depth seems reasonably conservative, and empirically
+ * works better in configurations with high CPU/bus clock ratios.
+ */
+
+#define compare_change_hazard() \
+ do { \
+ irq_disable_hazard(); \
+ irq_disable_hazard(); \
+ irq_disable_hazard(); \
+ irq_disable_hazard(); \
+ } while (0)
+
+int c0_compare_int_usable(void)
{
unsigned int delta;
unsigned int cnt;
*/
if (c0_compare_int_pending()) {
write_c0_compare(read_c0_count());
- irq_disable_hazard();
+ compare_change_hazard();
if (c0_compare_int_pending())
return 0;
}
cnt = read_c0_count();
cnt += delta;
write_c0_compare(cnt);
- irq_disable_hazard();
+ compare_change_hazard();
if ((int)(read_c0_count() - cnt) < 0)
break;
/* increase delta if the timer was already expired */
while ((int)(read_c0_count() - cnt) <= 0)
; /* Wait for expiry */
+ compare_change_hazard();
if (!c0_compare_int_pending())
return 0;
write_c0_compare(read_c0_count());
- irq_disable_hazard();
+ compare_change_hazard();
if (c0_compare_int_pending())
return 0;
return 1;
}
+#ifndef CONFIG_MIPS_MT_SMTC
+
int __cpuinit mips_clockevent_init(void)
{
uint64_t mips_freq = mips_hpt_frequency;
if (!cpu_has_counter || !mips_hpt_frequency)
return -ENXIO;
-#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 0;
-#endif
-
if (!c0_compare_int_usable())
return -ENXIO;
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->set_mode = mips_set_clock_mode;
cd->event_handler = mips_event_handler;
clockevents_register_device(cd);
cp0_timer_irq_installed = 1;
-#ifdef CONFIG_MIPS_MT_SMTC
-#define CPUCTR_IMASKBIT (0x100 << cp0_compare_irq)
- setup_irq_smtc(irq, &c0_compare_irqaction, CPUCTR_IMASKBIT);
-#else
setup_irq(irq, &c0_compare_irqaction);
-#endif
return 0;
}
+
+#endif /* Not CONFIG_MIPS_MT_SMTC */
--- /dev/null
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2007 MIPS Technologies, Inc.
+ * Copyright (C) 2007 Ralf Baechle <ralf@linux-mips.org>
+ * Copyright (C) 2008 Kevin D. Kissell, Paralogos sarl
+ */
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/percpu.h>
+
+#include <asm/smtc_ipi.h>
+#include <asm/time.h>
+#include <asm/cevt-r4k.h>
+
+/*
+ * Variant clock event timer support for SMTC on MIPS 34K, 1004K
+ * or other MIPS MT cores.
+ *
+ * Notes on SMTC Support:
+ *
+ * SMTC has multiple microthread TCs pretending to be Linux CPUs.
+ * But there's only one Count/Compare pair per VPE, and Compare
+ * interrupts are taken opportunisitically by available TCs
+ * bound to the VPE with the Count register. The new timer
+ * framework provides for global broadcasts, but we really
+ * want VPE-level multicasts for best behavior. So instead
+ * of invoking the high-level clock-event broadcast code,
+ * this version of SMTC support uses the historical SMTC
+ * multicast mechanisms "under the hood", appearing to the
+ * generic clock layer as if the interrupts are per-CPU.
+ *
+ * The approach taken here is to maintain a set of NR_CPUS
+ * virtual timers, and track which "CPU" needs to be alerted
+ * at each event.
+ *
+ * It's unlikely that we'll see a MIPS MT core with more than
+ * 2 VPEs, but we *know* that we won't need to handle more
+ * VPEs than we have "CPUs". So NCPUs arrays of NCPUs elements
+ * is always going to be overkill, but always going to be enough.
+ */
+
+unsigned long smtc_nexttime[NR_CPUS][NR_CPUS];
+static int smtc_nextinvpe[NR_CPUS];
+
+/*
+ * Timestamps stored are absolute values to be programmed
+ * into Count register. Valid timestamps will never be zero.
+ * If a Zero Count value is actually calculated, it is converted
+ * to be a 1, which will introduce 1 or two CPU cycles of error
+ * roughly once every four billion events, which at 1000 HZ means
+ * about once every 50 days. If that's actually a problem, one
+ * could alternate squashing 0 to 1 and to -1.
+ */
+
+#define MAKEVALID(x) (((x) == 0L) ? 1L : (x))
+#define ISVALID(x) ((x) != 0L)
+
+/*
+ * Time comparison is subtle, as it's really truncated
+ * modular arithmetic.
+ */
+
+#define IS_SOONER(a, b, reference) \
+ (((a) - (unsigned long)(reference)) < ((b) - (unsigned long)(reference)))
+
+/*
+ * CATCHUP_INCREMENT, used when the function falls behind the counter.
+ * Could be an increasing function instead of a constant;
+ */
+
+#define CATCHUP_INCREMENT 64
+
+static int mips_next_event(unsigned long delta,
+ struct clock_event_device *evt)
+{
+ unsigned long flags;
+ unsigned int mtflags;
+ unsigned long timestamp, reference, previous;
+ unsigned long nextcomp = 0L;
+ int vpe = current_cpu_data.vpe_id;
+ int cpu = smp_processor_id();
+ local_irq_save(flags);
+ mtflags = dmt();
+
+ /*
+ * Maintain the per-TC virtual timer
+ * and program the per-VPE shared Count register
+ * as appropriate here...
+ */
+ reference = (unsigned long)read_c0_count();
+ timestamp = MAKEVALID(reference + delta);
+ /*
+ * To really model the clock, we have to catch the case
+ * where the current next-in-VPE timestamp is the old
+ * timestamp for the calling CPE, but the new value is
+ * in fact later. In that case, we have to do a full
+ * scan and discover the new next-in-VPE CPU id and
+ * timestamp.
+ */
+ previous = smtc_nexttime[vpe][cpu];
+ if (cpu == smtc_nextinvpe[vpe] && ISVALID(previous)
+ && IS_SOONER(previous, timestamp, reference)) {
+ int i;
+ int soonest = cpu;
+
+ /*
+ * Update timestamp array here, so that new
+ * value gets considered along with those of
+ * other virtual CPUs on the VPE.
+ */
+ smtc_nexttime[vpe][cpu] = timestamp;
+ for_each_online_cpu(i) {
+ if (ISVALID(smtc_nexttime[vpe][i])
+ && IS_SOONER(smtc_nexttime[vpe][i],
+ smtc_nexttime[vpe][soonest], reference)) {
+ soonest = i;
+ }
+ }
+ smtc_nextinvpe[vpe] = soonest;
+ nextcomp = smtc_nexttime[vpe][soonest];
+ /*
+ * Otherwise, we don't have to process the whole array rank,
+ * we just have to see if the event horizon has gotten closer.
+ */
+ } else {
+ if (!ISVALID(smtc_nexttime[vpe][smtc_nextinvpe[vpe]]) ||
+ IS_SOONER(timestamp,
+ smtc_nexttime[vpe][smtc_nextinvpe[vpe]], reference)) {
+ smtc_nextinvpe[vpe] = cpu;
+ nextcomp = timestamp;
+ }
+ /*
+ * Since next-in-VPE may me the same as the executing
+ * virtual CPU, we update the array *after* checking
+ * its value.
+ */
+ smtc_nexttime[vpe][cpu] = timestamp;
+ }
+
+ /*
+ * It may be that, in fact, we don't need to update Compare,
+ * but if we do, we want to make sure we didn't fall into
+ * a crack just behind Count.
+ */
+ if (ISVALID(nextcomp)) {
+ write_c0_compare(nextcomp);
+ ehb();
+ /*
+ * We never return an error, we just make sure
+ * that we trigger the handlers as quickly as
+ * we can if we fell behind.
+ */
+ while ((nextcomp - (unsigned long)read_c0_count())
+ > (unsigned long)LONG_MAX) {
+ nextcomp += CATCHUP_INCREMENT;
+ write_c0_compare(nextcomp);
+ ehb();
+ }
+ }
+ emt(mtflags);
+ local_irq_restore(flags);
+ return 0;
+}
+
+
+void smtc_distribute_timer(int vpe)
+{
+ unsigned long flags;
+ unsigned int mtflags;
+ int cpu;
+ struct clock_event_device *cd;
+ unsigned long nextstamp = 0L;
+ unsigned long reference;
+
+
+repeat:
+ for_each_online_cpu(cpu) {
+ /*
+ * Find virtual CPUs within the current VPE who have
+ * unserviced timer requests whose time is now past.
+ */
+ local_irq_save(flags);
+ mtflags = dmt();
+ if (cpu_data[cpu].vpe_id == vpe &&
+ ISVALID(smtc_nexttime[vpe][cpu])) {
+ reference = (unsigned long)read_c0_count();
+ if ((smtc_nexttime[vpe][cpu] - reference)
+ > (unsigned long)LONG_MAX) {
+ smtc_nexttime[vpe][cpu] = 0L;
+ emt(mtflags);
+ local_irq_restore(flags);
+ /*
+ * We don't send IPIs to ourself.
+ */
+ if (cpu != smp_processor_id()) {
+ smtc_send_ipi(cpu, SMTC_CLOCK_TICK, 0);
+ } else {
+ cd = &per_cpu(mips_clockevent_device, cpu);
+ cd->event_handler(cd);
+ }
+ } else {
+ /* Local to VPE but Valid Time not yet reached. */
+ if (!ISVALID(nextstamp) ||
+ IS_SOONER(smtc_nexttime[vpe][cpu], nextstamp,
+ reference)) {
+ smtc_nextinvpe[vpe] = cpu;
+ nextstamp = smtc_nexttime[vpe][cpu];
+ }
+ emt(mtflags);
+ local_irq_restore(flags);
+ }
+ } else {
+ emt(mtflags);
+ local_irq_restore(flags);
+
+ }
+ }
+ /* Reprogram for interrupt at next soonest timestamp for VPE */
+ if (ISVALID(nextstamp)) {
+ write_c0_compare(nextstamp);
+ ehb();
+ if ((nextstamp - (unsigned long)read_c0_count())
+ > (unsigned long)LONG_MAX)
+ goto repeat;
+ }
+}
+
+
+irqreturn_t c0_compare_interrupt(int irq, void *dev_id)
+{
+ int cpu = smp_processor_id();
+
+ /* If we're running SMTC, we've got MIPS MT and therefore MIPS32R2 */
+ handle_perf_irq(1);
+
+ if (read_c0_cause() & (1 << 30)) {
+ /* Clear Count/Compare Interrupt */
+ write_c0_compare(read_c0_compare());
+ smtc_distribute_timer(cpu_data[cpu].vpe_id);
+ }
+ return IRQ_HANDLED;
+}
+
+
+int __cpuinit mips_clockevent_init(void)
+{
+ uint64_t mips_freq = mips_hpt_frequency;
+ unsigned int cpu = smp_processor_id();
+ struct clock_event_device *cd;
+ unsigned int irq;
+ int i;
+ int j;
+
+ if (!cpu_has_counter || !mips_hpt_frequency)
+ return -ENXIO;
+ if (cpu == 0) {
+ for (i = 0; i < num_possible_cpus(); i++) {
+ smtc_nextinvpe[i] = 0;
+ for (j = 0; j < num_possible_cpus(); j++)
+ smtc_nexttime[i][j] = 0L;
+ }
+ /*
+ * SMTC also can't have the usablility test
+ * run by secondary TCs once Compare is in use.
+ */
+ if (!c0_compare_int_usable())
+ return -ENXIO;
+ }
+
+ /*
+ * With vectored interrupts things are getting platform specific.
+ * get_c0_compare_int is a hook to allow a platform to return the
+ * interrupt number of it's liking.
+ */
+ irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
+ if (get_c0_compare_int)
+ irq = get_c0_compare_int();
+
+ cd = &per_cpu(mips_clockevent_device, cpu);
+
+ cd->name = "MIPS";
+ cd->features = CLOCK_EVT_FEAT_ONESHOT;
+
+ /* Calculate the min / max delta */
+ cd->mult = div_sc((unsigned long) mips_freq, NSEC_PER_SEC, 32);
+ cd->shift = 32;
+ cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
+ cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
+
+ cd->rating = 300;
+ cd->irq = irq;
+ cd->cpumask = cpumask_of_cpu(cpu);
+ cd->set_next_event = mips_next_event;
+ cd->set_mode = mips_set_clock_mode;
+ cd->event_handler = mips_event_handler;
+
+ clockevents_register_device(cd);
+
+ /*
+ * On SMTC we only want to do the data structure
+ * initialization and IRQ setup once.
+ */
+ if (cpu)
+ return 0;
+ /*
+ * And we need the hwmask associated with the c0_compare
+ * vector to be initialized.
+ */
+ irq_hwmask[irq] = (0x100 << cp0_compare_irq);
+ if (cp0_timer_irq_installed)
+ return 0;
+
+ cp0_timer_irq_installed = 1;
+
+ setup_irq(irq, &c0_compare_irqaction);
+
+ return 0;
+}
* interrupt is requested" restriction in the MIPS32/MIPS64 architecture makes
* using this version a gamble.
*/
-static void r4k_wait_irqoff(void)
+void r4k_wait_irqoff(void)
{
local_irq_disable();
if (!need_resched())
- __asm__(" .set mips3 \n"
+ __asm__(" .set push \n"
+ " .set mips3 \n"
" wait \n"
- " .set mips0 \n");
+ " .set pop \n");
local_irq_enable();
+ __asm__(" .globl __pastwait \n"
+ "__pastwait: \n");
+ return;
}
/*
and t0, a0, t1
#ifdef CONFIG_MIPS_MT_SMTC_IM_BACKSTOP
mfc0 t2, CP0_TCCONTEXT
- or t0, t0, t2
- mtc0 t0, CP0_TCCONTEXT
+ or t2, t0, t2
+ mtc0 t2, CP0_TCCONTEXT
#endif /* CONFIG_MIPS_MT_SMTC_IM_BACKSTOP */
xor t1, t1, t0
mtc0 t1, CP0_STATUS
-/* Copyright (C) 2004 Mips Technologies, Inc */
+/*
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) 2004 Mips Technologies, Inc
+ * Copyright (C) 2008 Kevin D. Kissell
+ */
#include <linux/clockchips.h>
#include <linux/kernel.h>
#include <asm/time.h>
#include <asm/addrspace.h>
#include <asm/smtc.h>
-#include <asm/smtc_ipi.h>
#include <asm/smtc_proc.h>
/*
asiduse smtc_live_asid[MAX_SMTC_TLBS][MAX_SMTC_ASIDS];
-/*
- * Clock interrupt "latch" buffers, per "CPU"
- */
-
-static atomic_t ipi_timer_latch[NR_CPUS];
/*
* Number of InterProcessor Interrupt (IPI) message buffers to allocate
* phys_cpu_present_map and the logical/physical mappings.
*/
-int __init mipsmt_build_cpu_map(int start_cpu_slot)
+int __init smtc_build_cpu_map(int start_cpu_slot)
{
int i, ntcs;
write_tc_c0_tcstatus((read_tc_c0_tcstatus()
& ~(TCSTATUS_TKSU | TCSTATUS_DA | TCSTATUS_IXMT))
| TCSTATUS_A);
- write_tc_c0_tccontext(0);
+ /*
+ * TCContext gets an offset from the base of the IPIQ array
+ * to be used in low-level code to detect the presence of
+ * an active IPI queue
+ */
+ write_tc_c0_tccontext((sizeof(struct smtc_ipi_q) * cpu) << 16);
/* Bind tc to vpe */
write_tc_c0_tcbind(vpe);
/* In general, all TCs should have the same cpu_data indications */
cpu_data[cpu].options &= ~MIPS_CPU_FPU;
cpu_data[cpu].vpe_id = vpe;
cpu_data[cpu].tc_id = tc;
+ /* Multi-core SMTC hasn't been tested, but be prepared */
+ cpu_data[cpu].core = (read_vpe_c0_ebase() >> 1) & 0xff;
}
+/*
+ * Tweak to get Count registes in as close a sync as possible.
+ * Value seems good for 34K-class cores.
+ */
+
+#define CP0_SKEW 8
-void mipsmt_prepare_cpus(void)
+void smtc_prepare_cpus(int cpus)
{
int i, vpe, tc, ntc, nvpe, tcpervpe[NR_CPUS], slop, cpu;
unsigned long flags;
IPIQ[i].head = IPIQ[i].tail = NULL;
spin_lock_init(&IPIQ[i].lock);
IPIQ[i].depth = 0;
- atomic_set(&ipi_timer_latch[i], 0);
}
/* cpu_data index starts at zero */
cpu = 0;
cpu_data[cpu].vpe_id = 0;
cpu_data[cpu].tc_id = 0;
+ cpu_data[cpu].core = (read_c0_ebase() >> 1) & 0xff;
cpu++;
/* Report on boot-time options */
write_vpe_c0_compare(0);
/* Propagate Config7 */
write_vpe_c0_config7(read_c0_config7());
- write_vpe_c0_count(read_c0_count());
+ write_vpe_c0_count(read_c0_count() + CP0_SKEW);
+ ehb();
}
/* enable multi-threading within VPE */
write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() | VPECONTROL_TE);
void smtc_init_secondary(void)
{
- /*
- * Start timer on secondary VPEs if necessary.
- * plat_timer_setup has already have been invoked by init/main
- * on "boot" TC. Like per_cpu_trap_init() hack, this assumes that
- * SMTC init code assigns TCs consdecutively and in ascending order
- * to across available VPEs.
- */
- if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
- ((read_c0_tcbind() & TCBIND_CURVPE)
- != cpu_data[smp_processor_id() - 1].vpe_id)){
- write_c0_compare(read_c0_count() + mips_hpt_frequency/HZ);
- }
-
local_irq_enable();
}
void smtc_smp_finish(void)
{
+ int cpu = smp_processor_id();
+
+ /*
+ * Lowest-numbered CPU per VPE starts a clock tick.
+ * Like per_cpu_trap_init() hack, this assumes that
+ * SMTC init code assigns TCs consdecutively and
+ * in ascending order across available VPEs.
+ */
+ if (cpu > 0 && (cpu_data[cpu].vpe_id != cpu_data[cpu - 1].vpe_id))
+ write_c0_compare(read_c0_count() + mips_hpt_frequency/HZ);
+
printk("TC %d going on-line as CPU %d\n",
cpu_data[smp_processor_id()].tc_id, smp_processor_id());
}
struct smtc_ipi *pipi;
unsigned long flags;
int mtflags;
+ unsigned long tcrestart;
+ extern void r4k_wait_irqoff(void), __pastwait(void);
if (cpu == smp_processor_id()) {
printk("Cannot Send IPI to self!\n");
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 interrupt */
smtc_ipi_nq(&IPIQ[cpu], pipi);
LOCK_CORE_PRA();
if ((tcstatus & TCSTATUS_IXMT) != 0) {
/*
- * Spin-waiting here can deadlock,
- * so we queue the message for the target TC.
+ * If we're in the the irq-off version of the wait
+ * loop, we need to force exit from the wait and
+ * do a direct post of the IPI.
+ */
+ if (cpu_wait == r4k_wait_irqoff) {
+ tcrestart = read_tc_c0_tcrestart();
+ if (tcrestart >= (unsigned long)r4k_wait_irqoff
+ && tcrestart < (unsigned long)__pastwait) {
+ write_tc_c0_tcrestart(__pastwait);
+ tcstatus &= ~TCSTATUS_IXMT;
+ write_tc_c0_tcstatus(tcstatus);
+ goto postdirect;
+ }
+ }
+ /*
+ * Otherwise we queue the message for the target TC
+ * to pick up when he does a local_irq_restore()
*/
write_tc_c0_tchalt(0);
UNLOCK_CORE_PRA();
- /* Try to reduce redundant timer interrupt messages */
- if (type == SMTC_CLOCK_TICK) {
- if (atomic_postincrement(&ipi_timer_latch[cpu])!=0){
- smtc_ipi_nq(&freeIPIq, pipi);
- return;
- }
- }
smtc_ipi_nq(&IPIQ[cpu], pipi);
} else {
- if (type == SMTC_CLOCK_TICK)
- atomic_inc(&ipi_timer_latch[cpu]);
+postdirect:
post_direct_ipi(cpu, pipi);
write_tc_c0_tchalt(0);
UNLOCK_CORE_PRA();
smp_call_function_interrupt();
}
-DECLARE_PER_CPU(struct clock_event_device, smtc_dummy_clockevent_device);
+DECLARE_PER_CPU(struct clock_event_device, mips_clockevent_device);
void ipi_decode(struct smtc_ipi *pipi)
{
struct clock_event_device *cd;
void *arg_copy = pipi->arg;
int type_copy = pipi->type;
- int ticks;
-
smtc_ipi_nq(&freeIPIq, pipi);
switch (type_copy) {
case SMTC_CLOCK_TICK:
irq_enter();
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--;
- }
+ cd = &per_cpu(mips_clockevent_device, cpu);
+ cd->event_handler(cd);
irq_exit();
break;
}
}
+/*
+ * Similar to smtc_ipi_replay(), but invoked from context restore,
+ * so it reuses the current exception frame rather than set up a
+ * new one with self_ipi.
+ */
+
void deferred_smtc_ipi(void)
{
- struct smtc_ipi *pipi;
- unsigned long flags;
-/* DEBUG */
- int q = smp_processor_id();
+ int cpu = smp_processor_id();
/*
* Test is not atomic, but much faster than a dequeue,
* and the vast majority of invocations will have a null queue.
+ * If irq_disabled when this was called, then any IPIs queued
+ * after we test last will be taken on the next irq_enable/restore.
+ * If interrupts were enabled, then any IPIs added after the
+ * last test will be taken directly.
*/
- if (IPIQ[q].head != NULL) {
- while((pipi = smtc_ipi_dq(&IPIQ[q])) != NULL) {
- /* ipi_decode() should be called with interrupts off */
- local_irq_save(flags);
+
+ while (IPIQ[cpu].head != NULL) {
+ struct smtc_ipi_q *q = &IPIQ[cpu];
+ struct smtc_ipi *pipi;
+ unsigned long flags;
+
+ /*
+ * It may be possible we'll come in with interrupts
+ * already enabled.
+ */
+ local_irq_save(flags);
+
+ spin_lock(&q->lock);
+ pipi = __smtc_ipi_dq(q);
+ spin_unlock(&q->lock);
+ if (pipi != NULL)
ipi_decode(pipi);
- local_irq_restore(flags);
- }
+ /*
+ * The use of the __raw_local restore isn't
+ * as obviously necessary here as in smtc_ipi_replay(),
+ * but it's more efficient, given that we're already
+ * running down the IPI queue.
+ */
+ __raw_local_irq_restore(flags);
}
}
/*
* SMTC-specific hacks invoked from elsewhere in the kernel.
- *
- * smtc_ipi_replay is called from raw_local_irq_restore which is only ever
- * called with interrupts disabled. We do rely on interrupts being disabled
- * here because using spin_lock_irqsave()/spin_unlock_irqrestore() would
- * result in a recursive call to raw_local_irq_restore().
*/
-static void __smtc_ipi_replay(void)
+ /*
+ * smtc_ipi_replay is called from raw_local_irq_restore
+ */
+
+void smtc_ipi_replay(void)
{
unsigned int cpu = smp_processor_id();
/*
* To the extent that we've ever turned interrupts off,
* we may have accumulated deferred IPIs. This is subtle.
- * If we use the smtc_ipi_qdepth() macro, we'll get an
- * exact number - but we'll also disable interrupts
- * and create a window of failure where a new IPI gets
- * queued after we test the depth but before we re-enable
- * interrupts. So long as IXMT never gets set, however,
* we should be OK: If we pick up something and dispatch
* it here, that's great. If we see nothing, but concurrent
* with this operation, another TC sends us an IPI, IXMT
* is clear, and we'll handle it as a real pseudo-interrupt
- * and not a pseudo-pseudo interrupt.
+ * and not a pseudo-pseudo interrupt. The important thing
+ * is to do the last check for queued message *after* the
+ * re-enabling of interrupts.
*/
- if (IPIQ[cpu].depth > 0) {
- while (1) {
- struct smtc_ipi_q *q = &IPIQ[cpu];
- struct smtc_ipi *pipi;
- extern void self_ipi(struct smtc_ipi *);
-
- spin_lock(&q->lock);
- pipi = __smtc_ipi_dq(q);
- spin_unlock(&q->lock);
- if (!pipi)
- break;
+ while (IPIQ[cpu].head != NULL) {
+ struct smtc_ipi_q *q = &IPIQ[cpu];
+ struct smtc_ipi *pipi;
+ unsigned long flags;
+ /*
+ * It's just possible we'll come in with interrupts
+ * already enabled.
+ */
+ local_irq_save(flags);
+
+ spin_lock(&q->lock);
+ pipi = __smtc_ipi_dq(q);
+ spin_unlock(&q->lock);
+ /*
+ ** But use a raw restore here to avoid recursion.
+ */
+ __raw_local_irq_restore(flags);
+
+ if (pipi) {
self_ipi(pipi);
smtc_cpu_stats[cpu].selfipis++;
}
}
}
-void smtc_ipi_replay(void)
-{
- raw_local_irq_disable();
- __smtc_ipi_replay();
-}
-
EXPORT_SYMBOL(smtc_ipi_replay);
void smtc_idle_loop_hook(void)
}
}
- /*
- * Now that we limit outstanding timer IPIs, check for hung TC
- */
- for (tc = 0; tc < NR_CPUS; tc++) {
- /* Don't check ourself - we'll dequeue IPIs just below */
- if ((tc != smp_processor_id()) &&
- 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, atomic_read(&ipi_timer_latch[tc]));
- clock_hang_reported[tc]++;
- }
- }
- }
emt(mtflags);
local_irq_restore(flags);
if (pdb_msg != &id_ho_db_msg[0])
printk("CPU%d: %s", smp_processor_id(), id_ho_db_msg);
#endif /* CONFIG_SMTC_IDLE_HOOK_DEBUG */
- /*
- * Replay any accumulated deferred IPIs. If "Instant Replay"
- * is in use, there should never be any.
- */
-#ifndef CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY
- {
- unsigned long flags;
-
- local_irq_save(flags);
- __smtc_ipi_replay();
- local_irq_restore(flags);
- }
-#endif /* CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY */
+ smtc_ipi_replay();
}
void smtc_soft_dump(void)
printk("%d: %ld\n", i, smtc_cpu_stats[i].selfipis);
}
smtc_ipi_qdump();
- printk("Timer IPI Backlogs:\n");
- for (i=0; i < NR_CPUS; i++) {
- printk("%d: %d\n", i, atomic_read(&ipi_timer_latch[i]));
- }
printk("%d Recoveries of \"stolen\" FPU\n",
atomic_read(&smtc_fpu_recoveries));
}
static void __init msmtc_smp_setup(void)
{
- mipsmt_build_cpu_map(0);
+ /*
+ * we won't get the definitive value until
+ * we've run smtc_prepare_cpus later, but
+ * we would appear to need an upper bound now.
+ */
+ smp_num_siblings = smtc_build_cpu_map(0);
}
static void __init msmtc_prepare_cpus(unsigned int max_cpus)
{
- mipsmt_prepare_cpus();
+ smtc_prepare_cpus(max_cpus);
}
struct plat_smp_ops msmtc_smp_ops = {
--- /dev/null
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2008 Kevin D. Kissell
+ */
+
+/*
+ * Definitions used for common event timer implementation
+ * for MIPS 4K-type processors and their MIPS MT variants.
+ * Avoids unsightly extern declarations in C files.
+ */
+#ifndef __ASM_CEVT_R4K_H
+#define __ASM_CEVT_R4K_H
+
+DECLARE_PER_CPU(struct clock_event_device, mips_clockevent_device);
+
+void mips_event_handler(struct clock_event_device *dev);
+int c0_compare_int_usable(void);
+void mips_set_clock_mode(enum clock_event_mode, struct clock_event_device *);
+irqreturn_t c0_compare_interrupt(int, void *);
+
+extern struct irqaction c0_compare_irqaction;
+extern int cp0_timer_irq_installed;
+
+/*
+ * Possibly handle a performance counter interrupt.
+ * Return true if the timer interrupt should not be checked
+ */
+
+static inline int handle_perf_irq(int r2)
+{
+ /*
+ * The performance counter overflow interrupt may be shared with the
+ * timer interrupt (cp0_perfcount_irq < 0). If it is and a
+ * performance counter has overflowed (perf_irq() == IRQ_HANDLED)
+ * and we can't reliably determine if a counter interrupt has also
+ * happened (!r2) then don't check for a timer interrupt.
+ */
+ return (cp0_perfcount_irq < 0) &&
+ perf_irq() == IRQ_HANDLED &&
+ !r2;
+}
+
+#endif /* __ASM_CEVT_R4K_H */
" .set pop \n"
" .endm");
+extern void smtc_ipi_replay(void);
+
static inline void raw_local_irq_enable(void)
{
+#ifdef CONFIG_MIPS_MT_SMTC
+ /*
+ * SMTC kernel needs to do a software replay of queued
+ * IPIs, at the cost of call overhead on each local_irq_enable()
+ */
+ smtc_ipi_replay();
+#endif
__asm__ __volatile__(
"raw_local_irq_enable"
: /* no outputs */
: "memory");
}
+
/*
* For cli() we have to insert nops to make sure that the new value
* has actually arrived in the status register before the end of this
" .set pop \n"
" .endm \n");
-extern void smtc_ipi_replay(void);
static inline void raw_local_irq_restore(unsigned long flags)
{
unsigned long __tmp1;
-#ifdef CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY
+#ifdef CONFIG_MIPS_MT_SMTC
/*
- * CONFIG_MIPS_MT_SMTC_INSTANT_REPLAY does prompt replay of deferred
+ * SMTC kernel needs to do a software replay of queued
* IPIs, at the cost of branch and call overhead on each
* local_irq_restore()
*/
: "memory");
}
+static inline void __raw_local_irq_restore(unsigned long flags)
+{
+ unsigned long __tmp1;
+
+ __asm__ __volatile__(
+ "raw_local_irq_restore\t%0"
+ : "=r" (__tmp1)
+ : "0" (flags)
+ : "memory");
+}
+
static inline int raw_irqs_disabled_flags(unsigned long flags)
{
#ifdef CONFIG_MIPS_MT_SMTC
*/
#include <asm/mips_mt.h>
+#include <asm/smtc_ipi.h>
/*
* System-wide SMTC status information
struct task_struct;
void smtc_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu);
-
+void self_ipi(struct smtc_ipi *);
void smtc_flush_tlb_asid(unsigned long asid);
-extern int mipsmt_build_cpu_map(int startslot);
-extern void mipsmt_prepare_cpus(void);
+extern int smtc_build_cpu_map(int startslot);
+extern void smtc_prepare_cpus(int cpus);
extern void smtc_smp_finish(void);
extern void smtc_boot_secondary(int cpu, struct task_struct *t);
extern void smtc_cpus_done(void);
+
/*
* Sharing the TLB between multiple VPEs means that the
* "random" index selection function is not allowed to
projects / openwrt / staging / blogic.git / commitdiff