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/*
* linux/arch/arm/kernel/fiq.c
*
* Copyright (C) 1998 Russell King
* FIQ support written by Philip Blundell <philb@gnu.org>, 1998.
*
* FIQ support re-written by Russell King to be more generic
*
* We now properly support a method by which the FIQ handlers can
* be stacked onto the vector. We still do not support sharing
* the FIQ vector itself.
*
* Operation is as follows:
* 1. Owner A claims FIQ:
* - default_fiq relinquishes control.
* 2. Owner A:
* - inserts code.
* - sets any registers,
* - enables FIQ.
* 3. Owner B claims FIQ:
* - if owner A has a relinquish function.
* - disable FIQs.
* - saves any registers.
* - returns zero.
* 4. Owner B:
* - inserts code.
* - sets any registers,
* - enables FIQ.
* 5. Owner B releases FIQ:
* - Owner A is asked to reacquire FIQ:
* - inserts code.
* - restores saved registers.
* - enables FIQ.
* 6. Goto 3
*/
#include <linux/config.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/init.h>
#include <asm/fiq.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#define FIQ_VECTOR 0x1c
static unsigned long no_fiq_insn;
#ifdef CONFIG_CPU_32
static inline void unprotect_page_0(void)
{
__asm__ __volatile__("mcr p15, 0, %0, c3, c0" :
: "r" (DOMAIN_USER_MANAGER |
DOMAIN_KERNEL_CLIENT |
DOMAIN_IO_CLIENT));
}
static inline void protect_page_0(void)
{
set_fs(get_fs());
}
#else
#define unprotect_page_0()
#define protect_page_0()
#endif
/* Default reacquire function
* - we always relinquish FIQ control
* - we always reacquire FIQ control
*/
int fiq_def_op(void *ref, int relinquish)
{
if (!relinquish) {
unprotect_page_0();
*(unsigned long *)FIQ_VECTOR = no_fiq_insn;
protect_page_0();
__flush_entry_to_ram(FIQ_VECTOR);
}
return 0;
}
static struct fiq_handler default_owner =
{ NULL, "default", fiq_def_op, NULL };
static struct fiq_handler *current_fiq = &default_owner;
int get_fiq_list(char *buf)
{
char *p = buf;
if (current_fiq != &default_owner)
p += sprintf(p, "FIQ: %s\n",
current_fiq->name);
return p - buf;
}
void set_fiq_handler(void *start, unsigned int length)
{
unprotect_page_0();
memcpy((void *)FIQ_VECTOR, start, length);
protect_page_0();
#if 0
/* This doesn'w work correctly. Ok, it's a misuse
* of the DMA flushing code, but it ought to work.
* More investigation required. Maybe it really
* needs the cache flushed.
*/
dma_cache_wback(FIQ_VECTOR, length);
#else
processor.u.armv3v4._flush_cache_area(FIQ_VECTOR, FIQ_VECTOR + length, 1);
#endif
}
void set_fiq_regs(struct pt_regs *regs)
{
/* not yet -
* this is temporary to get the floppy working
* again on RiscPC. It *will* become more
* generic.
*/
#ifdef CONFIG_ARCH_ACORN
extern void floppy_fiqsetup(unsigned long len, unsigned long addr,
unsigned long port);
floppy_fiqsetup(regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
#endif
}
void get_fiq_regs(struct pt_regs *regs)
{
/* not yet */
}
int claim_fiq(struct fiq_handler *f)
{
int ret = 0;
if (current_fiq) {
ret = -EBUSY;
if (current_fiq->fiq_op != NULL)
ret = current_fiq->fiq_op(current_fiq->dev_id, 1);
}
if (!ret) {
f->next = current_fiq;
current_fiq = f;
}
return ret;
}
void release_fiq(struct fiq_handler *f)
{
if (current_fiq != f) {
printk(KERN_ERR "%s FIQ trying to release %s FIQ\n",
f->name, current_fiq->name);
#ifdef CONFIG_DEBUG_ERRORS
__backtrace();
#endif
return;
}
do
current_fiq = current_fiq->next;
while (current_fiq->fiq_op(current_fiq->dev_id, 0));
}
__initfunc(void init_FIQ(void))
{
no_fiq_insn = *(unsigned long *)FIQ_VECTOR;
set_fs(get_fs());
}
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