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/errno.h>
#include <linux/kthread.h>
#include <linux/unistd.h>
#include <linux/io.h>
#include <asm/system.h>
#include <asm/atomic.h>
DEFINE_PER_CPU(struct pt_regs, __ipipe_tick_regs);
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 = bfin_no_irqs;
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_percpu_domain_data *p = ipipe_root_cpudom_ptr();
struct ipipe_domain *this_domain, *next_domain;
struct list_head *head, *pos;
struct ipipe_irqdesc *idesc;
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;
idesc = &this_domain->irqs[irq];
if (unlikely(test_bit(IPIPE_STICKY_FLAG, &idesc->control)))
head = &this_domain->p_link;
else {
head = __ipipe_pipeline.next;
next_domain = list_entry(head, struct ipipe_domain, p_link);
idesc = &next_domain->irqs[irq];
if (likely(test_bit(IPIPE_WIRED_FLAG, &idesc->control))) {
if (!m_ack && idesc->acknowledge != NULL)
idesc->acknowledge(irq, irq_to_desc(irq));
if (test_bit(IPIPE_SYNCDEFER_FLAG, &p->status))
s = __test_and_set_bit(IPIPE_STALL_FLAG,
&p->status);
__ipipe_dispatch_wired(next_domain, irq);
goto out;
}
}
/* Ack the interrupt. */
pos = head;
while (pos != &__ipipe_pipeline) {
next_domain = list_entry(pos, struct ipipe_domain, p_link);
idesc = &next_domain->irqs[irq];
if (test_bit(IPIPE_HANDLE_FLAG, &idesc->control)) {
__ipipe_set_irq_pending(next_domain, irq);
if (!m_ack && idesc->acknowledge != NULL) {
idesc->acknowledge(irq, irq_to_desc(irq));
m_ack = 1;
}
}
if (!test_bit(IPIPE_PASS_FLAG, &idesc->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_SYNCDEFER_FLAG, &p->status))
s = __test_and_set_bit(IPIPE_STALL_FLAG, &p->status);
/*
* If the interrupt preempted the head domain, then do not
* even try to walk the pipeline, unless an interrupt is
* pending for it.
*/
if (test_bit(IPIPE_AHEAD_FLAG, &this_domain->flags) &&
ipipe_head_cpudom_var(irqpend_himask) == 0)
goto out;
__ipipe_walk_pipeline(head);
out:
if (!s)
__clear_bit(IPIPE_STALL_FLAG, &p->status);
}
void __ipipe_enable_irqdesc(struct ipipe_domain *ipd, unsigned irq)
{
struct irq_desc *desc = irq_to_desc(irq);
int prio = __ipipe_get_irq_priority(irq);
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)
{
int prio = __ipipe_get_irq_priority(irq);
if (ipd != &ipipe_root &&
atomic_dec_and_test(&__ipipe_irq_lvdepth[prio]))
__clear_bit(prio, &__ipipe_irq_lvmask);
}
EXPORT_SYMBOL(__ipipe_disable_irqdesc);
int __ipipe_syscall_root(struct pt_regs *regs)
{
struct ipipe_percpu_domain_data *p;
unsigned long flags;
int ret;
/*
* 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 (regs->orig_p0 < NR_syscalls) {
void (*hook)(void) = (void (*)(void))__ipipe_irq_tail_hook;
hook();
if ((current->flags & PF_EVNOTIFY) == 0)
return 0;
}
/*
* This routine either returns:
* 0 -- if the syscall is to be passed to Linux;
* >0 -- if the syscall should not be passed to Linux, and no
* tail work should be performed;
* <0 -- 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))
return 0;
ret = __ipipe_dispatch_event(IPIPE_EVENT_SYSCALL, regs);
local_irq_save_hw(flags);
if (!__ipipe_root_domain_p) {
local_irq_restore_hw(flags);
return 1;
}
p = ipipe_root_cpudom_ptr();
if ((p->irqpend_himask & IPIPE_IRQMASK_VIRT) != 0)
__ipipe_sync_pipeline(IPIPE_IRQMASK_VIRT);
local_irq_restore_hw(flags);
return -ret;
}
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;
#ifdef CONFIG_IPIPE_DEBUG
if (irq >= IPIPE_NR_IRQS ||
(ipipe_virtual_irq_p(irq)
&& !test_bit(irq - IPIPE_VIRQ_BASE, &__ipipe_virtual_irq_map)))
return -EINVAL;
#endif
local_irq_save_hw(flags);
__ipipe_handle_irq(irq, NULL);
local_irq_restore_hw(flags);
return 1;
}
asmlinkage void __ipipe_sync_root(void)
{
void (*irq_tail_hook)(void) = (void (*)(void))__ipipe_irq_tail_hook;
unsigned long flags;
BUG_ON(irqs_disabled());
local_irq_save_hw(flags);
if (irq_tail_hook)
irq_tail_hook();
clear_thread_flag(TIF_IRQ_SYNC);
if (ipipe_root_cpudom_var(irqpend_himask) != 0)
__ipipe_sync_pipeline(IPIPE_IRQMASK_ANY);
local_irq_restore_hw(flags);
}
void ___ipipe_sync_pipeline(unsigned long syncmask)
{
if (__ipipe_root_domain_p &&
test_bit(IPIPE_SYNCDEFER_FLAG, &ipipe_root_cpudom_var(status)))
return;
__ipipe_sync_stage(syncmask);
}
void __ipipe_disable_root_irqs_hw(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.
*/
bfin_sti(__ipipe_irq_lvmask);
__set_bit(IPIPE_STALL_FLAG, &ipipe_root_cpudom_var(status));
}
void __ipipe_enable_root_irqs_hw(void)
{
__clear_bit(IPIPE_STALL_FLAG, &ipipe_root_cpudom_var(status));
bfin_sti(bfin_irq_flags);
}
/*
* We could use standard atomic bitops in the following root status
* manipulation routines, but let's prepare for SMP support in the
* same move, preventing CPU migration as required.
*/
void __ipipe_stall_root(void)
{
unsigned long *p, flags;
local_irq_save_hw(flags);
p = &__ipipe_root_status;
__set_bit(IPIPE_STALL_FLAG, p);
local_irq_restore_hw(flags);
}
EXPORT_SYMBOL(__ipipe_stall_root);
unsigned long __ipipe_test_and_stall_root(void)
{
unsigned long *p, flags;
int x;
local_irq_save_hw(flags);
p = &__ipipe_root_status;
x = __test_and_set_bit(IPIPE_STALL_FLAG, p);
local_irq_restore_hw(flags);
return x;
}
EXPORT_SYMBOL(__ipipe_test_and_stall_root);
unsigned long __ipipe_test_root(void)
{
const unsigned long *p;
unsigned long flags;
int x;
local_irq_save_hw_smp(flags);
p = &__ipipe_root_status;
x = test_bit(IPIPE_STALL_FLAG, p);
local_irq_restore_hw_smp(flags);
return x;
}
EXPORT_SYMBOL(__ipipe_test_root);
void __ipipe_lock_root(void)
{
unsigned long *p, flags;
local_irq_save_hw(flags);
p = &__ipipe_root_status;
__set_bit(IPIPE_SYNCDEFER_FLAG, p);
local_irq_restore_hw(flags);
}
EXPORT_SYMBOL(__ipipe_lock_root);
void __ipipe_unlock_root(void)
{
unsigned long *p, flags;
local_irq_save_hw(flags);
p = &__ipipe_root_status;
__clear_bit(IPIPE_SYNCDEFER_FLAG, p);
local_irq_restore_hw(flags);
}
EXPORT_SYMBOL(__ipipe_unlock_root);