drivers/of/fdt_address.c

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