linux/drivers/of/fdt_address.c
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   1/*
   2 * FDT Address translation based on u-boot fdt_support.c which in turn was
   3 * based on the kernel unflattened DT address translation code.
   4 *
   5 * (C) Copyright 2007
   6 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
   7 *
   8 * Copyright 2010-2011 Freescale Semiconductor, Inc.
   9 *
  10 * This program is free software; you can redistribute it and/or modify
  11 * it under the terms of the GNU General Public License as published by
  12 * the Free Software Foundation; either version 2, or (at your option)
  13 * any later version.
  14 */
  15
  16#define pr_fmt(fmt)     "OF: fdt: " fmt
  17
  18#include <linux/kernel.h>
  19#include <linux/libfdt.h>
  20#include <linux/of.h>
  21#include <linux/of_fdt.h>
  22#include <linux/sizes.h>
  23
  24/* Max address size we deal with */
  25#define OF_MAX_ADDR_CELLS       4
  26#define OF_CHECK_COUNTS(na, ns) ((na) > 0 && (na) <= OF_MAX_ADDR_CELLS && \
  27                        (ns) > 0)
  28
  29/* Debug utility */
  30#ifdef DEBUG
  31static void __init of_dump_addr(const char *s, const __be32 *addr, int na)
  32{
  33        pr_debug("%s", s);
  34        while(na--)
  35                pr_cont(" %08x", *(addr++));
  36        pr_cont("\n");
  37}
  38#else
  39static void __init of_dump_addr(const char *s, const __be32 *addr, int na) { }
  40#endif
  41
  42/* Callbacks for bus specific translators */
  43struct of_bus {
  44        void            (*count_cells)(const void *blob, int parentoffset,
  45                                int *addrc, int *sizec);
  46        u64             (*map)(__be32 *addr, const __be32 *range,
  47                                int na, int ns, int pna);
  48        int             (*translate)(__be32 *addr, u64 offset, int na);
  49};
  50
  51/* Default translator (generic bus) */
  52static void __init fdt_bus_default_count_cells(const void *blob, int parentoffset,
  53                                               int *addrc, int *sizec)
  54{
  55        const __be32 *prop;
  56
  57        if (addrc) {
  58                prop = fdt_getprop(blob, parentoffset, "#address-cells", NULL);
  59                if (prop)
  60                        *addrc = be32_to_cpup(prop);
  61                else
  62                        *addrc = dt_root_addr_cells;
  63        }
  64
  65        if (sizec) {
  66                prop = fdt_getprop(blob, parentoffset, "#size-cells", NULL);
  67                if (prop)
  68                        *sizec = be32_to_cpup(prop);
  69                else
  70                        *sizec = dt_root_size_cells;
  71        }
  72}
  73
  74static u64 __init fdt_bus_default_map(__be32 *addr, const __be32 *range,
  75                                      int na, int ns, int pna)
  76{
  77        u64 cp, s, da;
  78
  79        cp = of_read_number(range, na);
  80        s  = of_read_number(range + na + pna, ns);
  81        da = of_read_number(addr, na);
  82
  83        pr_debug("default map, cp=%llx, s=%llx, da=%llx\n",
  84            cp, s, da);
  85
  86        if (da < cp || da >= (cp + s))
  87                return OF_BAD_ADDR;
  88        return da - cp;
  89}
  90
  91static int __init fdt_bus_default_translate(__be32 *addr, u64 offset, int na)
  92{
  93        u64 a = of_read_number(addr, na);
  94        memset(addr, 0, na * 4);
  95        a += offset;
  96        if (na > 1)
  97                addr[na - 2] = cpu_to_fdt32(a >> 32);
  98        addr[na - 1] = cpu_to_fdt32(a & 0xffffffffu);
  99
 100        return 0;
 101}
 102
 103/* Array of bus specific translators */
 104static const struct of_bus of_busses[] __initconst = {
 105        /* Default */
 106        {
 107                .count_cells = fdt_bus_default_count_cells,
 108                .map = fdt_bus_default_map,
 109                .translate = fdt_bus_default_translate,
 110        },
 111};
 112
 113static int __init fdt_translate_one(const void *blob, int parent,
 114                                    const struct of_bus *bus,
 115                                    const struct of_bus *pbus, __be32 *addr,
 116                                    int na, int ns, int pna, const char *rprop)
 117{
 118        const __be32 *ranges;
 119        int rlen;
 120        int rone;
 121        u64 offset = OF_BAD_ADDR;
 122
 123        ranges = fdt_getprop(blob, parent, rprop, &rlen);
 124        if (!ranges)
 125                return 1;
 126        if (rlen == 0) {
 127                offset = of_read_number(addr, na);
 128                memset(addr, 0, pna * 4);
 129                pr_debug("empty ranges, 1:1 translation\n");
 130                goto finish;
 131        }
 132
 133        pr_debug("walking ranges...\n");
 134
 135        /* Now walk through the ranges */
 136        rlen /= 4;
 137        rone = na + pna + ns;
 138        for (; rlen >= rone; rlen -= rone, ranges += rone) {
 139                offset = bus->map(addr, ranges, na, ns, pna);
 140                if (offset != OF_BAD_ADDR)
 141                        break;
 142        }
 143        if (offset == OF_BAD_ADDR) {
 144                pr_debug("not found !\n");
 145                return 1;
 146        }
 147        memcpy(addr, ranges + na, 4 * pna);
 148
 149 finish:
 150        of_dump_addr("parent translation for:", addr, pna);
 151        pr_debug("with offset: %llx\n", offset);
 152
 153        /* Translate it into parent bus space */
 154        return pbus->translate(addr, offset, pna);
 155}
 156
 157/*
 158 * Translate an address from the device-tree into a CPU physical address,
 159 * this walks up the tree and applies the various bus mappings on the
 160 * way.
 161 *
 162 * Note: We consider that crossing any level with #size-cells == 0 to mean
 163 * that translation is impossible (that is we are not dealing with a value
 164 * that can be mapped to a cpu physical address). This is not really specified
 165 * that way, but this is traditionally the way IBM at least do things
 166 */
 167static u64 __init fdt_translate_address(const void *blob, int node_offset)
 168{
 169        int parent, len;
 170        const struct of_bus *bus, *pbus;
 171        const __be32 *reg;
 172        __be32 addr[OF_MAX_ADDR_CELLS];
 173        int na, ns, pna, pns;
 174        u64 result = OF_BAD_ADDR;
 175
 176        pr_debug("** translation for device %s **\n",
 177                 fdt_get_name(blob, node_offset, NULL));
 178
 179        reg = fdt_getprop(blob, node_offset, "reg", &len);
 180        if (!reg) {
 181                pr_err("warning: device tree node '%s' has no address.\n",
 182                        fdt_get_name(blob, node_offset, NULL));
 183                goto bail;
 184        }
 185
 186        /* Get parent & match bus type */
 187        parent = fdt_parent_offset(blob, node_offset);
 188        if (parent < 0)
 189                goto bail;
 190        bus = &of_busses[0];
 191
 192        /* Cound address cells & copy address locally */
 193        bus->count_cells(blob, parent, &na, &ns);
 194        if (!OF_CHECK_COUNTS(na, ns)) {
 195                pr_err("Bad cell count for %s\n",
 196                       fdt_get_name(blob, node_offset, NULL));
 197                goto bail;
 198        }
 199        memcpy(addr, reg, na * 4);
 200
 201        pr_debug("bus (na=%d, ns=%d) on %s\n",
 202                 na, ns, fdt_get_name(blob, parent, NULL));
 203        of_dump_addr("translating address:", addr, na);
 204
 205        /* Translate */
 206        for (;;) {
 207                /* Switch to parent bus */
 208                node_offset = parent;
 209                parent = fdt_parent_offset(blob, node_offset);
 210
 211                /* If root, we have finished */
 212                if (parent < 0) {
 213                        pr_debug("reached root node\n");
 214                        result = of_read_number(addr, na);
 215                        break;
 216                }
 217
 218                /* Get new parent bus and counts */
 219                pbus = &of_busses[0];
 220                pbus->count_cells(blob, parent, &pna, &pns);
 221                if (!OF_CHECK_COUNTS(pna, pns)) {
 222                        pr_err("Bad cell count for %s\n",
 223                                fdt_get_name(blob, node_offset, NULL));
 224                        break;
 225                }
 226
 227                pr_debug("parent bus (na=%d, ns=%d) on %s\n",
 228                         pna, pns, fdt_get_name(blob, parent, NULL));
 229
 230                /* Apply bus translation */
 231                if (fdt_translate_one(blob, node_offset, bus, pbus,
 232                                        addr, na, ns, pna, "ranges"))
 233                        break;
 234
 235                /* Complete the move up one level */
 236                na = pna;
 237                ns = pns;
 238                bus = pbus;
 239
 240                of_dump_addr("one level translation:", addr, na);
 241        }
 242 bail:
 243        return result;
 244}
 245
 246/**
 247 * of_flat_dt_translate_address - translate DT addr into CPU phys addr
 248 * @node: node in the flat blob
 249 */
 250u64 __init of_flat_dt_translate_address(unsigned long node)
 251{
 252        return fdt_translate_address(initial_boot_params, node);
 253}
 254