2005-06-22 22:58:45 +02:00
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/*
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* Bus error event handling code for DECstation/DECsystem 3100
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* and 2100 (KN01) systems equipped with parity error detection
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* logic.
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*
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* Copyright (c) 2005 Maciej W. Rozycki
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/spinlock.h>
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#include <linux/types.h>
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#include <asm/inst.h>
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2006-12-06 12:50:23 +01:00
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#include <asm/irq_regs.h>
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2005-06-22 22:58:45 +02:00
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#include <asm/mipsregs.h>
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#include <asm/page.h>
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2006-12-06 12:50:23 +01:00
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#include <asm/ptrace.h>
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2005-06-22 22:58:45 +02:00
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#include <asm/system.h>
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#include <asm/traps.h>
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#include <asm/uaccess.h>
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#include <asm/dec/kn01.h>
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/* CP0 hazard avoidance. */
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#define BARRIER \
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__asm__ __volatile__( \
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".set push\n\t" \
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".set noreorder\n\t" \
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"nop\n\t" \
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".set pop\n\t")
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/*
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* Bits 7:0 of the Control Register are write-only -- the
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* corresponding bits of the Status Register have a different
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* meaning. Hence we use a cache. It speeds up things a bit
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* as well.
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*
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* There is no default value -- it has to be initialized.
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*/
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u16 cached_kn01_csr;
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2010-02-27 12:53:36 +01:00
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static DEFINE_RAW_SPINLOCK(kn01_lock);
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2005-06-22 22:58:45 +02:00
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static inline void dec_kn01_be_ack(void)
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{
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2005-07-01 18:10:40 +02:00
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volatile u16 *csr = (void *)CKSEG1ADDR(KN01_SLOT_BASE + KN01_CSR);
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2005-06-22 22:58:45 +02:00
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unsigned long flags;
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2010-02-27 12:53:36 +01:00
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raw_spin_lock_irqsave(&kn01_lock, flags);
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2005-06-22 22:58:45 +02:00
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*csr = cached_kn01_csr | KN01_CSR_MEMERR; /* Clear bus IRQ. */
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iob();
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2010-02-27 12:53:36 +01:00
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raw_spin_unlock_irqrestore(&kn01_lock, flags);
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2005-06-22 22:58:45 +02:00
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}
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static int dec_kn01_be_backend(struct pt_regs *regs, int is_fixup, int invoker)
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{
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2005-07-01 18:10:40 +02:00
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volatile u32 *kn01_erraddr = (void *)CKSEG1ADDR(KN01_SLOT_BASE +
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KN01_ERRADDR);
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2005-06-22 22:58:45 +02:00
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static const char excstr[] = "exception";
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static const char intstr[] = "interrupt";
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static const char cpustr[] = "CPU";
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static const char mreadstr[] = "memory read";
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static const char readstr[] = "read";
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static const char writestr[] = "write";
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static const char timestr[] = "timeout";
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static const char paritystr[] = "parity error";
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int data = regs->cp0_cause & 4;
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unsigned int __user *pc = (unsigned int __user *)regs->cp0_epc +
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((regs->cp0_cause & CAUSEF_BD) != 0);
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union mips_instruction insn;
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unsigned long entrylo, offset;
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long asid, entryhi, vaddr;
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const char *kind, *agent, *cycle, *event;
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unsigned long address;
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u32 erraddr = *kn01_erraddr;
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int action = MIPS_BE_FATAL;
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/* Ack ASAP, so that any subsequent errors get caught. */
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dec_kn01_be_ack();
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kind = invoker ? intstr : excstr;
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agent = cpustr;
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if (invoker)
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address = erraddr;
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else {
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/* Bloody hardware doesn't record the address for reads... */
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if (data) {
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/* This never faults. */
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__get_user(insn.word, pc);
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vaddr = regs->regs[insn.i_format.rs] +
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insn.i_format.simmediate;
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} else
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vaddr = (long)pc;
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if (KSEGX(vaddr) == CKSEG0 || KSEGX(vaddr) == CKSEG1)
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address = CPHYSADDR(vaddr);
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else {
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/* Peek at what physical address the CPU used. */
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asid = read_c0_entryhi();
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entryhi = asid & (PAGE_SIZE - 1);
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entryhi |= vaddr & ~(PAGE_SIZE - 1);
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write_c0_entryhi(entryhi);
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BARRIER;
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tlb_probe();
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/* No need to check for presence. */
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tlb_read();
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entrylo = read_c0_entrylo0();
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write_c0_entryhi(asid);
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offset = vaddr & (PAGE_SIZE - 1);
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address = (entrylo & ~(PAGE_SIZE - 1)) | offset;
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}
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}
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/* Treat low 256MB as memory, high -- as I/O. */
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if (address < 0x10000000) {
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cycle = mreadstr;
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event = paritystr;
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} else {
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cycle = invoker ? writestr : readstr;
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event = timestr;
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}
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if (is_fixup)
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action = MIPS_BE_FIXUP;
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if (action != MIPS_BE_FIXUP)
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printk(KERN_ALERT "Bus error %s: %s %s %s at %#010lx\n",
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kind, agent, cycle, event, address);
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return action;
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}
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int dec_kn01_be_handler(struct pt_regs *regs, int is_fixup)
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{
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return dec_kn01_be_backend(regs, is_fixup, 0);
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}
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2006-10-09 01:00:31 +02:00
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irqreturn_t dec_kn01_be_interrupt(int irq, void *dev_id)
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2005-06-22 22:58:45 +02:00
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{
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2005-07-01 18:10:40 +02:00
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volatile u16 *csr = (void *)CKSEG1ADDR(KN01_SLOT_BASE + KN01_CSR);
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2006-10-09 01:00:31 +02:00
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struct pt_regs *regs = get_irq_regs();
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2005-06-22 22:58:45 +02:00
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int action;
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if (!(*csr & KN01_CSR_MEMERR))
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return IRQ_NONE; /* Must have been video. */
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action = dec_kn01_be_backend(regs, 0, 1);
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if (action == MIPS_BE_DISCARD)
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return IRQ_HANDLED;
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/*
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* FIXME: Find the affected processes and kill them, otherwise
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* we must die.
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*
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* The interrupt is asynchronously delivered thus EPC and RA
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* may be irrelevant, but are printed for a reference.
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*/
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printk(KERN_ALERT "Fatal bus interrupt, epc == %08lx, ra == %08lx\n",
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regs->cp0_epc, regs->regs[31]);
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die("Unrecoverable bus error", regs);
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}
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void __init dec_kn01_be_init(void)
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{
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2005-07-01 18:10:40 +02:00
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volatile u16 *csr = (void *)CKSEG1ADDR(KN01_SLOT_BASE + KN01_CSR);
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2005-06-22 22:58:45 +02:00
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unsigned long flags;
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2010-02-27 12:53:36 +01:00
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raw_spin_lock_irqsave(&kn01_lock, flags);
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2005-06-22 22:58:45 +02:00
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/* Preset write-only bits of the Control Register cache. */
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cached_kn01_csr = *csr;
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cached_kn01_csr &= KN01_CSR_STATUS | KN01_CSR_PARDIS | KN01_CSR_TXDIS;
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cached_kn01_csr |= KN01_CSR_LEDS;
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/* Enable parity error detection. */
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cached_kn01_csr &= ~KN01_CSR_PARDIS;
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*csr = cached_kn01_csr;
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iob();
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2010-02-27 12:53:36 +01:00
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raw_spin_unlock_irqrestore(&kn01_lock, flags);
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2005-06-22 22:58:45 +02:00
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/* Clear any leftover errors from the firmware. */
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dec_kn01_be_ack();
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}
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