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/*
* File: arch/blackfin/kernel/irqchip.c
* Based on:
* Author:
*
* Created:
* Description: This file contains the simple DMA Implementation for Blackfin
*
* Modified:
* Copyright 2004-2006 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
* 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, see the file COPYING, or write
* to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/kernel_stat.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/seq_file.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <asm/trace.h>
#include <asm/pda.h>
static atomic_t irq_err_count;
void ack_bad_irq(unsigned int irq)
{
atomic_inc(&irq_err_count);
printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
}
static struct irq_desc bad_irq_desc = {
.handle_irq = handle_bad_irq,
.lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
};
#ifdef CONFIG_CPUMASK_OFFSTACK
/* We are not allocating a variable-sized bad_irq_desc.affinity */
#error "Blackfin architecture does not support CONFIG_CPUMASK_OFFSTACK."
#endif
#ifdef CONFIG_PROC_FS
int show_interrupts(struct seq_file *p, void *v)
{
int i = *(loff_t *) v, j;
struct irqaction *action;
unsigned long flags;
if (i < NR_IRQS) {
spin_lock_irqsave(&irq_desc[i].lock, flags);
action = irq_desc[i].action;
if (!action)
goto skip;
seq_printf(p, "%3d: ", i);
for_each_online_cpu(j)
seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
seq_printf(p, " %8s", irq_desc[i].chip->name);
seq_printf(p, " %s", action->name);
for (action = action->next; action; action = action->next)
seq_printf(p, " %s", action->name);
seq_putc(p, '\n');
skip:
spin_unlock_irqrestore(&irq_desc[i].lock, flags);
} else if (i == NR_IRQS) {
seq_printf(p, "NMI: ");
for_each_online_cpu(j)
seq_printf(p, "%10u ", cpu_pda[j].__nmi_count);
seq_printf(p, " CORE Non Maskable Interrupt\n");
seq_printf(p, "Err: %10u\n", atomic_read(&irq_err_count));
}
return 0;
}
#endif
#ifdef CONFIG_DEBUG_STACKOVERFLOW
static void check_stack_overflow(int irq)
{
/* Debugging check for stack overflow: is there less than STACK_WARN free? */
long sp = __get_SP() & (THREAD_SIZE - 1);
if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
dump_stack();
pr_emerg("irq%i: possible stack overflow only %ld bytes free\n",
irq, sp - sizeof(struct thread_info));
}
}
#else
static inline void check_stack_overflow(int irq) { }
#endif
#ifndef CONFIG_IPIPE
static void maybe_lower_to_irq14(void)
{
unsigned short pending, other_ints;
/*
* If we're the only interrupt running (ignoring IRQ15 which
* is for syscalls), lower our priority to IRQ14 so that
* softirqs run at that level. If there's another,
* lower-level interrupt, irq_exit will defer softirqs to
* that. If the interrupt pipeline is enabled, we are already
* running at IRQ14 priority, so we don't need this code.
*/
CSYNC();
pending = bfin_read_IPEND() & ~0x8000;
other_ints = pending & (pending - 1);
if (other_ints == 0)
lower_to_irq14();
}
#else
static inline void maybe_lower_to_irq14(void) { }
#endif
/*
* do_IRQ handles all hardware IRQs. Decoded IRQs should not
* come via this function. Instead, they should provide their
* own 'handler'
*/
#ifdef CONFIG_DO_IRQ_L1
__attribute__((l1_text))
#endif
asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
irq_enter();
check_stack_overflow(irq);
/*
* Some hardware gives randomly wrong interrupts. Rather
* than crashing, do something sensible.
*/
if (irq >= NR_IRQS)
handle_bad_irq(irq, &bad_irq_desc);
else
generic_handle_irq(irq);
maybe_lower_to_irq14();
irq_exit();
set_irq_regs(old_regs);
}
void __init init_IRQ(void)
{
init_arch_irq();
#ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
/* Now that evt_ivhw is set up, turn this on */
trace_buff_offset = 0;
bfin_write_TBUFCTL(BFIN_TRACE_ON);
printk(KERN_INFO "Hardware Trace expanded to %ik\n",
1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
#endif
}
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