linux/arch/blackfin/kernel/ipipe.c

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/* -*- linux-c -*-
* linux/arch/blackfin/kernel/ipipe.c
*
* Copyright (C) 2005-2007 Philippe Gerum.
*
* 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, Inc., 675 Mass Ave, Cambridge MA 02139,
* USA; 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.
*
* Architecture-dependent I-pipe support for the Blackfin.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/percpu.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/kthread.h>
#include <asm/unistd.h>
#include <asm/system.h>
#include <asm/atomic.h>
#include <asm/io.h>
static int create_irq_threads;
DEFINE_PER_CPU(struct pt_regs, __ipipe_tick_regs);
static DEFINE_PER_CPU(unsigned long, pending_irqthread_mask);
static DEFINE_PER_CPU(int [IVG13 + 1], pending_irq_count);
asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs);
static void __ipipe_no_irqtail(void);
unsigned long __ipipe_irq_tail_hook = (unsigned long)&__ipipe_no_irqtail;
EXPORT_SYMBOL(__ipipe_irq_tail_hook);
unsigned long __ipipe_core_clock;
EXPORT_SYMBOL(__ipipe_core_clock);
unsigned long __ipipe_freq_scale;
EXPORT_SYMBOL(__ipipe_freq_scale);
atomic_t __ipipe_irq_lvdepth[IVG15 + 1];
unsigned long __ipipe_irq_lvmask = __all_masked_irq_flags;
EXPORT_SYMBOL(__ipipe_irq_lvmask);
static void __ipipe_ack_irq(unsigned irq, struct irq_desc *desc)
{
desc->ipipe_ack(irq, desc);
}
/*
* __ipipe_enable_pipeline() -- We are running on the boot CPU, hw
* interrupts are off, and secondary CPUs are still lost in space.
*/
void __ipipe_enable_pipeline(void)
{
unsigned irq;
__ipipe_core_clock = get_cclk(); /* Fetch this once. */
__ipipe_freq_scale = 1000000000UL / __ipipe_core_clock;
for (irq = 0; irq < NR_IRQS; ++irq)
ipipe_virtualize_irq(ipipe_root_domain,
irq,
(ipipe_irq_handler_t)&asm_do_IRQ,
NULL,
&__ipipe_ack_irq,
IPIPE_HANDLE_MASK | IPIPE_PASS_MASK);
}
/*
* __ipipe_handle_irq() -- IPIPE's generic IRQ handler. An optimistic
* interrupt protection log is maintained here for each domain. Hw
* interrupts are masked on entry.
*/
void __ipipe_handle_irq(unsigned irq, struct pt_regs *regs)
{
struct ipipe_domain *this_domain, *next_domain;
struct list_head *head, *pos;
int m_ack, s = -1;
/*
* Software-triggered IRQs do not need any ack. The contents
* of the register frame should only be used when processing
* the timer interrupt, but not for handling any other
* interrupt.
*/
m_ack = (regs == NULL || irq == IRQ_SYSTMR || irq == IRQ_CORETMR);
this_domain = ipipe_current_domain;
if (unlikely(test_bit(IPIPE_STICKY_FLAG, &this_domain->irqs[irq].control)))
head = &this_domain->p_link;
else {
head = __ipipe_pipeline.next;
next_domain = list_entry(head, struct ipipe_domain, p_link);
if (likely(test_bit(IPIPE_WIRED_FLAG, &next_domain->irqs[irq].control))) {
if (!m_ack && next_domain->irqs[irq].acknowledge != NULL)
next_domain->irqs[irq].acknowledge(irq, irq_desc + irq);
if (test_bit(IPIPE_ROOTLOCK_FLAG, &ipipe_root_domain->flags))
s = __test_and_set_bit(IPIPE_STALL_FLAG,
&ipipe_root_cpudom_var(status));
__ipipe_dispatch_wired(next_domain, irq);
goto finalize;
return;
}
}
/* Ack the interrupt. */
pos = head;
while (pos != &__ipipe_pipeline) {
next_domain = list_entry(pos, struct ipipe_domain, p_link);
/*
* For each domain handling the incoming IRQ, mark it
* as pending in its log.
*/
if (test_bit(IPIPE_HANDLE_FLAG, &next_domain->irqs[irq].control)) {
/*
* Domains that handle this IRQ are polled for
* acknowledging it by decreasing priority
* order. The interrupt must be made pending
* _first_ in the domain's status flags before
* the PIC is unlocked.
*/
__ipipe_set_irq_pending(next_domain, irq);
if (!m_ack && next_domain->irqs[irq].acknowledge != NULL) {
next_domain->irqs[irq].acknowledge(irq, irq_desc + irq);
m_ack = 1;
}
}
/*
* If the domain does not want the IRQ to be passed
* down the interrupt pipe, exit the loop now.
*/
if (!test_bit(IPIPE_PASS_FLAG, &next_domain->irqs[irq].control))
break;
pos = next_domain->p_link.next;
}
/*
* Now walk the pipeline, yielding control to the highest
* priority domain that has pending interrupt(s) or
* immediately to the current domain if the interrupt has been
* marked as 'sticky'. This search does not go beyond the
* current domain in the pipeline. We also enforce the
* additional root stage lock (blackfin-specific). */
if (test_bit(IPIPE_ROOTLOCK_FLAG, &ipipe_root_domain->flags))
s = __test_and_set_bit(IPIPE_STALL_FLAG,
&ipipe_root_cpudom_var(status));
finalize:
__ipipe_walk_pipeline(head);
if (!s)
__clear_bit(IPIPE_STALL_FLAG,
&ipipe_root_cpudom_var(status));
}
int __ipipe_check_root(void)
{
return ipipe_root_domain_p;
}
void __ipipe_enable_irqdesc(struct ipipe_domain *ipd, unsigned irq)
{
struct irq_desc *desc = irq_desc + irq;
int prio = desc->ic_prio;
desc->depth = 0;
if (ipd != &ipipe_root &&
atomic_inc_return(&__ipipe_irq_lvdepth[prio]) == 1)
__set_bit(prio, &__ipipe_irq_lvmask);
}
EXPORT_SYMBOL(__ipipe_enable_irqdesc);
void __ipipe_disable_irqdesc(struct ipipe_domain *ipd, unsigned irq)
{
struct irq_desc *desc = irq_desc + irq;
int prio = desc->ic_prio;
if (ipd != &ipipe_root &&
atomic_dec_and_test(&__ipipe_irq_lvdepth[prio]))
__clear_bit(prio, &__ipipe_irq_lvmask);
}
EXPORT_SYMBOL(__ipipe_disable_irqdesc);
void __ipipe_stall_root_raw(void)
{
/*
* This code is called by the ins{bwl} routines (see
* arch/blackfin/lib/ins.S), which are heavily used by the
* network stack. It masks all interrupts but those handled by
* non-root domains, so that we keep decent network transfer
* rates for Linux without inducing pathological jitter for
* the real-time domain.
*/
__asm__ __volatile__ ("sti %0;" : : "d"(__ipipe_irq_lvmask));
__set_bit(IPIPE_STALL_FLAG,
&ipipe_root_cpudom_var(status));
}
void __ipipe_unstall_root_raw(void)
{
__clear_bit(IPIPE_STALL_FLAG,
&ipipe_root_cpudom_var(status));
__asm__ __volatile__ ("sti %0;" : : "d"(bfin_irq_flags));
}
int __ipipe_syscall_root(struct pt_regs *regs)
{
unsigned long flags;
/* We need to run the IRQ tail hook whenever we don't
* propagate a syscall to higher domains, because we know that
* important operations might be pending there (e.g. Xenomai
* deferred rescheduling). */
if (!__ipipe_syscall_watched_p(current, regs->orig_p0)) {
void (*hook)(void) = (void (*)(void))__ipipe_irq_tail_hook;
hook();
return 0;
}
/*
* This routine either returns:
* 0 -- if the syscall is to be passed to Linux;
* 1 -- if the syscall should not be passed to Linux, and no
* tail work should be performed;
* -1 -- if the syscall should not be passed to Linux but the
* tail work has to be performed (for handling signals etc).
*/
if (__ipipe_event_monitored_p(IPIPE_EVENT_SYSCALL) &&
__ipipe_dispatch_event(IPIPE_EVENT_SYSCALL, regs) > 0) {
if (ipipe_root_domain_p && !in_atomic()) {
/*
* Sync pending VIRQs before _TIF_NEED_RESCHED
* is tested.
*/
local_irq_save_hw(flags);
if ((ipipe_root_cpudom_var(irqpend_himask) & IPIPE_IRQMASK_VIRT) != 0)
__ipipe_sync_pipeline(IPIPE_IRQMASK_VIRT);
local_irq_restore_hw(flags);
return -1;
}
return 1;
}
return 0;
}
unsigned long ipipe_critical_enter(void (*syncfn) (void))
{
unsigned long flags;
local_irq_save_hw(flags);
return flags;
}
void ipipe_critical_exit(unsigned long flags)
{
local_irq_restore_hw(flags);
}
static void __ipipe_no_irqtail(void)
{
}
int ipipe_get_sysinfo(struct ipipe_sysinfo *info)
{
info->ncpus = num_online_cpus();
info->cpufreq = ipipe_cpu_freq();
info->archdep.tmirq = IPIPE_TIMER_IRQ;
info->archdep.tmfreq = info->cpufreq;
return 0;
}
/*
* ipipe_trigger_irq() -- Push the interrupt at front of the pipeline
* just like if it has been actually received from a hw source. Also
* works for virtual interrupts.
*/
int ipipe_trigger_irq(unsigned irq)
{
unsigned long flags;
if (irq >= IPIPE_NR_IRQS ||
(ipipe_virtual_irq_p(irq)
&& !test_bit(irq - IPIPE_VIRQ_BASE, &__ipipe_virtual_irq_map)))
return -EINVAL;
local_irq_save_hw(flags);
__ipipe_handle_irq(irq, NULL);
local_irq_restore_hw(flags);
return 1;
}
/* Move Linux IRQ to threads. */
static int do_irqd(void *__desc)
{
struct irq_desc *desc = __desc;
unsigned irq = desc - irq_desc;
int thrprio = desc->thr_prio;
int thrmask = 1 << thrprio;
int cpu = smp_processor_id();
cpumask_t cpumask;
sigfillset(&current->blocked);
current->flags |= PF_NOFREEZE;
cpumask = cpumask_of_cpu(cpu);
set_cpus_allowed(current, cpumask);
ipipe_setscheduler_root(current, SCHED_FIFO, 50 + thrprio);
while (!kthread_should_stop()) {
local_irq_disable();
if (!(desc->status & IRQ_SCHEDULED)) {
set_current_state(TASK_INTERRUPTIBLE);
resched:
local_irq_enable();
schedule();
local_irq_disable();
}
__set_current_state(TASK_RUNNING);
/*
* If higher priority interrupt servers are ready to
* run, reschedule immediately. We need this for the
* GPIO demux IRQ handler to unmask the interrupt line
* _last_, after all GPIO IRQs have run.
*/
if (per_cpu(pending_irqthread_mask, cpu) & ~(thrmask|(thrmask-1)))
goto resched;
if (--per_cpu(pending_irq_count[thrprio], cpu) == 0)
per_cpu(pending_irqthread_mask, cpu) &= ~thrmask;
desc->status &= ~IRQ_SCHEDULED;
desc->thr_handler(irq, &__raw_get_cpu_var(__ipipe_tick_regs));
local_irq_enable();
}
__set_current_state(TASK_RUNNING);
return 0;
}
static void kick_irqd(unsigned irq, void *cookie)
{
struct irq_desc *desc = irq_desc + irq;
int thrprio = desc->thr_prio;
int thrmask = 1 << thrprio;
int cpu = smp_processor_id();
if (!(desc->status & IRQ_SCHEDULED)) {
desc->status |= IRQ_SCHEDULED;
per_cpu(pending_irqthread_mask, cpu) |= thrmask;
++per_cpu(pending_irq_count[thrprio], cpu);
wake_up_process(desc->thread);
}
}
int ipipe_start_irq_thread(unsigned irq, struct irq_desc *desc)
{
if (desc->thread || !create_irq_threads)
return 0;
desc->thread = kthread_create(do_irqd, desc, "IRQ %d", irq);
if (desc->thread == NULL) {
printk(KERN_ERR "irqd: could not create IRQ thread %d!\n", irq);
return -ENOMEM;
}
wake_up_process(desc->thread);
desc->thr_handler = ipipe_root_domain->irqs[irq].handler;
ipipe_root_domain->irqs[irq].handler = &kick_irqd;
return 0;
}
void __init ipipe_init_irq_threads(void)
{
unsigned irq;
struct irq_desc *desc;
create_irq_threads = 1;
for (irq = 0; irq < NR_IRQS; irq++) {
desc = irq_desc + irq;
if (desc->action != NULL ||
(desc->status & IRQ_NOREQUEST) != 0)
ipipe_start_irq_thread(irq, desc);
}
}
EXPORT_SYMBOL(show_stack);
#ifdef CONFIG_IPIPE_TRACE_MCOUNT
void notrace _mcount(void);
EXPORT_SYMBOL(_mcount);
#endif /* CONFIG_IPIPE_TRACE_MCOUNT */