/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*
* TILE SMP support routines.
*/
#include <linux/smp.h>
#include <linux/irq.h>
#include <asm/cacheflush.h>
HV_Topology smp_topology __write_once;
/*
* Top-level send_IPI*() functions to send messages to other cpus.
*/
/* Set by smp_send_stop() to avoid recursive panics. */
static int stopping_cpus;
void send_IPI_single(int cpu, int tag)
{
HV_Recipient recip = {
.y = cpu / smp_width,
.x = cpu % smp_width,
.state = HV_TO_BE_SENT
};
int rc = hv_send_message(&recip, 1, (HV_VirtAddr)&tag, sizeof(tag));
BUG_ON(rc <= 0);
}
void send_IPI_many(const struct cpumask *mask, int tag)
{
HV_Recipient recip[NR_CPUS];
int cpu, sent;
int nrecip = 0;
int my_cpu = smp_processor_id();
for_each_cpu(cpu, mask) {
HV_Recipient *r;
BUG_ON(cpu == my_cpu);
r = &recip[nrecip++];
r->y = cpu / smp_width;
r->x = cpu % smp_width;
r->state = HV_TO_BE_SENT;
}
sent = 0;
while (sent < nrecip) {
int rc = hv_send_message(recip, nrecip,
(HV_VirtAddr)&tag, sizeof(tag));
if (rc <= 0) {
if (!stopping_cpus) /* avoid recursive panic */
panic("hv_send_message returned %d", rc);
break;
}
sent += rc;
}
}
void send_IPI_allbutself(int tag)
{
struct cpumask mask;
cpumask_copy(&mask, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &mask);
send_IPI_many(&mask, tag);
}
/*
* Provide smp_call_function_mask, but also run function locally
* if specified in the mask.
*/
void on_each_cpu_mask(const struct cpumask *mask, void (*func)(void *),
void *info, bool wait)
{
int cpu = get_cpu();
smp_call_function_many(mask, func, info, wait);
if (cpumask_test_cpu(cpu, mask)) {
local_irq_disable();
func(info);
local_irq_enable();
}
put_cpu();
}
/*
* Functions related to starting/stopping cpus.
*/
/* Handler to start the current cpu. */
static void smp_start_cpu_interrupt(void)
{
extern unsigned long start_cpu_function_addr;
get_irq_regs()->pc = start_cpu_function_addr;
}
/* Handler to stop the current cpu. */
static void smp_stop_cpu_interrupt(void)
{
set_cpu_online(smp_processor_id(), 0);
raw_local_irq_disable_all();
for (;;)
asm("nap");
}
/* This function calls the 'stop' function on all other CPUs in the system. */
void smp_send_stop(void)
{
stopping_cpus = 1;
send_IPI_allbutself(MSG_TAG_STOP_CPU);
}
/*
* Dispatch code called from hv_message_intr() for HV_MSG_TILE hv messages.
*/
void evaluate_message(int tag)
{
switch (tag) {
case MSG_TAG_START_CPU: /* Start up a cpu */
smp_start_cpu_interrupt();
break;
case MSG_TAG_STOP_CPU: /* Sent to shut down slave CPU's */
smp_stop_cpu_interrupt();
break;
case MSG_TAG_CALL_FUNCTION_MANY: /* Call function on cpumask */
generic_smp_call_function_interrupt();
break;
case MSG_TAG_CALL_FUNCTION_SINGLE: /* Call function on one other CPU */
generic_smp_call_function_single_interrupt();
break;
default:
panic("Unknown IPI message tag %d", tag);
break;
}
}
/*
* flush_icache_range() code uses smp_call_function().
*/
struct ipi_flush {
unsigned long start;
unsigned long end;
};
static void ipi_flush_icache_range(void *info)
{
struct ipi_flush *flush = (struct ipi_flush *) info;
__flush_icache_range(flush->start, flush->end);
}
void flush_icache_range(unsigned long start, unsigned long end)
{
struct ipi_flush flush = { start, end };
preempt_disable();
on_each_cpu(ipi_flush_icache_range, &flush, 1);
preempt_enable();
}
/*
* The smp_send_reschedule() path does not use the hv_message_intr()
* path but instead the faster tile_dev_intr() path for interrupts.
*/
irqreturn_t handle_reschedule_ipi(int irq, void *token)
{
/*
* Nothing to do here; when we return from interrupt, the
* rescheduling will occur there. But do bump the interrupt
* profiler count in the meantime.
*/
__get_cpu_var(irq_stat).irq_resched_count++;
return IRQ_HANDLED;
}
void smp_send_reschedule(int cpu)
{
HV_Coord coord;
WARN_ON(cpu_is_offline(cpu));
coord.y = cpu / smp_width;
coord.x = cpu % smp_width;
hv_trigger_ipi(coord, IRQ_RESCHEDULE);
}
