// SPDX-License-Identifier: GPL-2.0
/*
 * ranges.c: Handle ranges in newer proms for obio/sbus.
 *
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 */

#include <linux/init.h>
#include <linux/module.h>

#include <asm/openprom.h>
#include <asm/oplib.h>
#include <asm/types.h>

static struct linux_prom_ranges promlib_obio_ranges[PROMREG_MAX];
static int num_obio_ranges;

/* Adjust register values based upon the ranges parameters. */
static void prom_adjust_regs(struct linux_prom_registers *regp, int nregs,
                             struct linux_prom_ranges *rangep, int nranges)
{
        int regc, rngc;

        for (regc = 0; regc < nregs; regc++) {
                for (rngc = 0; rngc < nranges; rngc++)
                        if (regp[regc].which_io == rangep[rngc].ot_child_space)
                                break; /* Fount it */
                if (rngc == nranges) /* oops */
                        prom_printf("adjust_regs: Could not find range with matching bus type...\n");
                regp[regc].which_io = rangep[rngc].ot_parent_space;
                regp[regc].phys_addr -= rangep[rngc].ot_child_base;
                regp[regc].phys_addr += rangep[rngc].ot_parent_base;
        }
}

static void prom_adjust_ranges(struct linux_prom_ranges *ranges1, int nranges1,
                               struct linux_prom_ranges *ranges2, int nranges2)
{
        int rng1c, rng2c;

        for (rng1c = 0; rng1c < nranges1; rng1c++) {
                for (rng2c = 0; rng2c < nranges2; rng2c++)
                        if (ranges1[rng1c].ot_parent_space == ranges2[rng2c].ot_child_space &&
                           ranges1[rng1c].ot_parent_base >= ranges2[rng2c].ot_child_base &&
                           ranges2[rng2c].ot_child_base + ranges2[rng2c].or_size - ranges1[rng1c].ot_parent_base > 0U)
                        break;
                if (rng2c == nranges2) /* oops */
                        prom_printf("adjust_ranges: Could not find matching bus type...\n");
                else if (ranges1[rng1c].ot_parent_base + ranges1[rng1c].or_size > ranges2[rng2c].ot_child_base + ranges2[rng2c].or_size)
                        ranges1[rng1c].or_size = ranges2[rng2c].ot_child_base + ranges2[rng2c].or_size - ranges1[rng1c].ot_parent_base;
                ranges1[rng1c].ot_parent_space = ranges2[rng2c].ot_parent_space;
                ranges1[rng1c].ot_parent_base += ranges2[rng2c].ot_parent_base;
        }
}

/* Apply probed obio ranges to registers passed, if no ranges return. */
void prom_apply_obio_ranges(struct linux_prom_registers *regs, int nregs)
{
        if (num_obio_ranges)
                prom_adjust_regs(regs, nregs, promlib_obio_ranges, num_obio_ranges);
}
EXPORT_SYMBOL(prom_apply_obio_ranges);

void __init prom_ranges_init(void)
{
        phandle node, obio_node;
        int success;

        num_obio_ranges = 0;

        /* Check for obio and sbus ranges. */
        node = prom_getchild(prom_root_node);
        obio_node = prom_searchsiblings(node, "obio");

        if (obio_node) {
                success = prom_getproperty(obio_node, "ranges",
                                           (char *) promlib_obio_ranges,
                                           sizeof(promlib_obio_ranges));
                if (success != -1)
                        num_obio_ranges = (success / sizeof(struct linux_prom_ranges));
        }

        if (num_obio_ranges)
                prom_printf("PROMLIB: obio_ranges %d\n", num_obio_ranges);
}

void prom_apply_generic_ranges(phandle node, phandle parent,
                               struct linux_prom_registers *regs, int nregs)
{
        int success;
        int num_ranges;
        struct linux_prom_ranges ranges[PROMREG_MAX];

        success = prom_getproperty(node, "ranges",
                                   (char *) ranges,
                                   sizeof(ranges));
        if (success != -1) {
                num_ranges = (success / sizeof(struct linux_prom_ranges));
                if (parent) {
                        struct linux_prom_ranges parent_ranges[PROMREG_MAX];
                        int num_parent_ranges;

                        success = prom_getproperty(parent, "ranges",
                                                   (char *) parent_ranges,
                                                   sizeof(parent_ranges));
                        if (success != -1) {
                                num_parent_ranges = (success / sizeof(struct linux_prom_ranges));
                                prom_adjust_ranges(ranges, num_ranges, parent_ranges, num_parent_ranges);
                        }
                }
                prom_adjust_regs(regs, nregs, ranges, num_ranges);
        }
}