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/*
* linux/kernel/resource.c
*
* Copyright (C) 1995 Linus Torvalds
* David Hinds
*
* Kernel io-region resource management
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/ioport.h>
#define IOTABLE_SIZE 128
typedef struct resource_entry_t {
u_long from, num;
const char *name;
struct resource_entry_t *next;
} resource_entry_t;
static resource_entry_t iolist = { 0, 0, "", NULL };
static resource_entry_t iotable[IOTABLE_SIZE];
/*
* This generates the report for /proc/ioports
*/
int get_ioport_list(char *buf)
{
resource_entry_t *p;
int len = 0;
for (p = iolist.next; (p) && (len < 4000); p = p->next)
len += sprintf(buf+len, "%04lx-%04lx : %s\n",
p->from, p->from+p->num-1, p->name);
if (p)
len += sprintf(buf+len, "4K limit reached!\n");
return len;
}
/*
* The workhorse function: find where to put a new entry
*/
static resource_entry_t *find_gap(resource_entry_t *root,
u_long from, u_long num)
{
unsigned long flags;
resource_entry_t *p;
if (from > from+num-1)
return NULL;
save_flags(flags);
cli();
for (p = root; ; p = p->next) {
if ((p != root) && (p->from+p->num-1 >= from)) {
p = NULL;
break;
}
if ((p->next == NULL) || (p->next->from > from+num-1))
break;
}
restore_flags(flags);
return p;
}
/*
* Call this from the device driver to register the ioport region.
*/
void request_region(unsigned int from, unsigned int num, const char *name)
{
resource_entry_t *p;
int i;
for (i = 0; i < IOTABLE_SIZE; i++)
if (iotable[i].num == 0)
break;
if (i == IOTABLE_SIZE)
printk("warning: ioport table is full\n");
else {
p = find_gap(&iolist, from, num);
if (p == NULL)
return;
iotable[i].name = name;
iotable[i].from = from;
iotable[i].num = num;
iotable[i].next = p->next;
p->next = &iotable[i];
return;
}
}
/*
* Call this when the device driver is unloaded
*/
void release_region(unsigned int from, unsigned int num)
{
resource_entry_t *p, *q;
for (p = &iolist; ; p = q) {
q = p->next;
if (q == NULL)
break;
if ((q->from == from) && (q->num == num)) {
q->num = 0;
p->next = q->next;
return;
}
}
}
/*
* Call this to check the ioport region before probing
*/
int check_region(unsigned int from, unsigned int num)
{
return (find_gap(&iolist, from, num) == NULL) ? -EBUSY : 0;
}
/* Called from init/main.c to reserve IO ports. */
void reserve_setup(char *str, int *ints)
{
int i;
for (i = 1; i < ints[0]; i += 2)
request_region(ints[i], ints[i+1], "reserved");
}
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