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Annotation of Gnu-Mach/linux/src/kernel/resource.c, revision 1.1

1.1     ! root        1: /*
        !             2:  *     linux/kernel/resource.c
        !             3:  *
        !             4:  * Copyright (C) 1995  Linus Torvalds
        !             5:  *                     David Hinds
        !             6:  *
        !             7:  * Kernel io-region resource management
        !             8:  */
        !             9: 
        !            10: #include <linux/sched.h>
        !            11: #include <linux/kernel.h>
        !            12: #include <linux/errno.h>
        !            13: #include <linux/types.h>
        !            14: #include <linux/ioport.h>
        !            15: 
        !            16: #define IOTABLE_SIZE 128
        !            17: 
        !            18: typedef struct resource_entry_t {
        !            19:        u_long from, num;
        !            20:        const char *name;
        !            21:        struct resource_entry_t *next;
        !            22: } resource_entry_t;
        !            23: 
        !            24: static resource_entry_t iolist = { 0, 0, "", NULL };
        !            25: 
        !            26: static resource_entry_t iotable[IOTABLE_SIZE];
        !            27: 
        !            28: /*
        !            29:  * This generates the report for /proc/ioports
        !            30:  */
        !            31: int get_ioport_list(char *buf)
        !            32: {
        !            33:        resource_entry_t *p;
        !            34:        int len = 0;
        !            35: 
        !            36:        for (p = iolist.next; (p) && (len < 4000); p = p->next)
        !            37:                len += sprintf(buf+len, "%04lx-%04lx : %s\n",
        !            38:                           p->from, p->from+p->num-1, p->name);
        !            39:        if (p)
        !            40:                len += sprintf(buf+len, "4K limit reached!\n");
        !            41:        return len;
        !            42: }
        !            43: 
        !            44: /*
        !            45:  * The workhorse function: find where to put a new entry
        !            46:  */
        !            47: static resource_entry_t *find_gap(resource_entry_t *root,
        !            48:                                  u_long from, u_long num)
        !            49: {
        !            50:        unsigned long flags;
        !            51:        resource_entry_t *p;
        !            52:        
        !            53:        if (from > from+num-1)
        !            54:                return NULL;
        !            55:        save_flags(flags);
        !            56:        cli();
        !            57:        for (p = root; ; p = p->next) {
        !            58:                if ((p != root) && (p->from+p->num-1 >= from)) {
        !            59:                        p = NULL;
        !            60:                        break;
        !            61:                }
        !            62:                if ((p->next == NULL) || (p->next->from > from+num-1))
        !            63:                        break;
        !            64:        }
        !            65:        restore_flags(flags);
        !            66:        return p;
        !            67: }
        !            68: 
        !            69: /*
        !            70:  * Call this from the device driver to register the ioport region.
        !            71:  */
        !            72: void request_region(unsigned int from, unsigned int num, const char *name)
        !            73: {
        !            74:        resource_entry_t *p;
        !            75:        int i;
        !            76: 
        !            77:        for (i = 0; i < IOTABLE_SIZE; i++)
        !            78:                if (iotable[i].num == 0)
        !            79:                        break;
        !            80:        if (i == IOTABLE_SIZE)
        !            81:                printk("warning: ioport table is full\n");
        !            82:        else {
        !            83:                p = find_gap(&iolist, from, num);
        !            84:                if (p == NULL)
        !            85:                        return;
        !            86:                iotable[i].name = name;
        !            87:                iotable[i].from = from;
        !            88:                iotable[i].num = num;
        !            89:                iotable[i].next = p->next;
        !            90:                p->next = &iotable[i];
        !            91:                return;
        !            92:        }
        !            93: }
        !            94: 
        !            95: /* 
        !            96:  * Call this when the device driver is unloaded
        !            97:  */
        !            98: void release_region(unsigned int from, unsigned int num)
        !            99: {
        !           100:        resource_entry_t *p, *q;
        !           101: 
        !           102:        for (p = &iolist; ; p = q) {
        !           103:                q = p->next;
        !           104:                if (q == NULL)
        !           105:                        break;
        !           106:                if ((q->from == from) && (q->num == num)) {
        !           107:                        q->num = 0;
        !           108:                        p->next = q->next;
        !           109:                        return;
        !           110:                }
        !           111:        }
        !           112: }
        !           113: 
        !           114: /*
        !           115:  * Call this to check the ioport region before probing
        !           116:  */
        !           117: int check_region(unsigned int from, unsigned int num)
        !           118: {
        !           119:        return (find_gap(&iolist, from, num) == NULL) ? -EBUSY : 0;
        !           120: }
        !           121: 
        !           122: /* Called from init/main.c to reserve IO ports. */
        !           123: void reserve_setup(char *str, int *ints)
        !           124: {
        !           125:        int i;
        !           126: 
        !           127:        for (i = 1; i < ints[0]; i += 2)
        !           128:                request_region(ints[i], ints[i+1], "reserved");
        !           129: }

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