arch/x86/platform/olpc/olpc_dt.c

   1 /*
   2  * OLPC-specific OFW device tree support code.
   3  *
   4  * Paul Mackerras       August 1996.
   5  * Copyright (C) 1996-2005 Paul Mackerras.
   6  *
   7  *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
   8  *    {engebret|bergner}@us.ibm.com
   9  *
  10  *  Adapted for sparc by David S. Miller davem@davemloft.net
  11  *  Adapted for x86/OLPC by Andres Salomon <dilinger@queued.net>
  12  *
  13  *      This program is free software; you can redistribute it and/or
  14  *      modify it under the terms of the GNU General Public License
  15  *      as published by the Free Software Foundation; either version
  16  *      2 of the License, or (at your option) any later version.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bootmem.h>
  21 #include <linux/of.h>
  22 #include <linux/of_platform.h>
  23 #include <linux/of_pdt.h>
  24 #include <asm/olpc.h>
  25 #include <asm/olpc_ofw.h>
  26
  27 static phandle __init olpc_dt_getsibling(phandle node)
  28 {
  29         const void *args[] = { (void *)node };
  30         void *res[] = { &node };
  31
  32         if ((s32)node == -1)
  33                 return 0;
  34
  35         if (olpc_ofw("peer", args, res) || (s32)node == -1)
  36                 return 0;
  37
  38         return node;
  39 }
  40
  41 static phandle __init olpc_dt_getchild(phandle node)
  42 {
  43         const void *args[] = { (void *)node };
  44         void *res[] = { &node };
  45
  46         if ((s32)node == -1)
  47                 return 0;
  48
  49         if (olpc_ofw("child", args, res) || (s32)node == -1) {
  50                 pr_err("PROM: %s: fetching child failed!\n", __func__);
  51                 return 0;
  52         }
  53
  54         return node;
  55 }
  56
  57 static int __init olpc_dt_getproplen(phandle node, const char *prop)
  58 {
  59         const void *args[] = { (void *)node, prop };
  60         int len;
  61         void *res[] = { &len };
  62
  63         if ((s32)node == -1)
  64                 return -1;
  65
  66         if (olpc_ofw("getproplen", args, res)) {
  67                 pr_err("PROM: %s: getproplen failed!\n", __func__);
  68                 return -1;
  69         }
  70
  71         return len;
  72 }
  73
  74 static int __init olpc_dt_getproperty(phandle node, const char *prop,
  75                 char *buf, int bufsize)
  76 {
  77         int plen;
  78
  79         plen = olpc_dt_getproplen(node, prop);
  80         if (plen > bufsize || plen < 1) {
  81                 return -1;
  82         } else {
  83                 const void *args[] = { (void *)node, prop, buf, (void *)plen };
  84                 void *res[] = { &plen };
  85
  86                 if (olpc_ofw("getprop", args, res)) {
  87                         pr_err("PROM: %s: getprop failed!\n", __func__);
  88                         return -1;
  89                 }
  90         }
  91
  92         return plen;
  93 }
  94
  95 static int __init olpc_dt_nextprop(phandle node, char *prev, char *buf)
  96 {
  97         const void *args[] = { (void *)node, prev, buf };
  98         int success;
  99         void *res[] = { &success };
 100
 101         buf[0] = '\0';
 102
 103         if ((s32)node == -1)
 104                 return -1;
 105
 106         if (olpc_ofw("nextprop", args, res) || success != 1)
 107                 return -1;
 108
 109         return 0;
 110 }
 111
 112 static int __init olpc_dt_pkg2path(phandle node, char *buf,
 113                 const int buflen, int *len)
 114 {
 115         const void *args[] = { (void *)node, buf, (void *)buflen };
 116         void *res[] = { len };
 117
 118         if ((s32)node == -1)
 119                 return -1;
 120
 121         if (olpc_ofw("package-to-path", args, res) || *len < 1)
 122                 return -1;
 123
 124         return 0;
 125 }
 126
 127 static unsigned int prom_early_allocated __initdata;
 128
 129 void * __init prom_early_alloc(unsigned long size)
 130 {
 131         static u8 *mem;
 132         static size_t free_mem;
 133         void *res;
 134
 135         if (free_mem < size) {
 136                 const size_t chunk_size = max(PAGE_SIZE, size);
 137
 138                 /*
 139                  * To mimimize the number of allocations, grab at least
 140                  * PAGE_SIZE of memory (that's an arbitrary choice that's
 141                  * fast enough on the platforms we care about while minimizing
 142                  * wasted bootmem) and hand off chunks of it to callers.
 143                  */
 144                 res = alloc_bootmem(chunk_size);
 145                 BUG_ON(!res);
 146                 prom_early_allocated += chunk_size;
 147                 memset(res, 0, chunk_size);
 148                 free_mem = chunk_size;
 149                 mem = res;
 150         }
 151
 152         /* allocate from the local cache */
 153         free_mem -= size;
 154         res = mem;
 155         mem += size;
 156         return res;
 157 }
 158
 159 static struct of_pdt_ops prom_olpc_ops __initdata = {
 160         .nextprop = olpc_dt_nextprop,
 161         .getproplen = olpc_dt_getproplen,
 162         .getproperty = olpc_dt_getproperty,
 163         .getchild = olpc_dt_getchild,
 164         .getsibling = olpc_dt_getsibling,
 165         .pkg2path = olpc_dt_pkg2path,
 166 };
 167
 168 static phandle __init olpc_dt_finddevice(const char *path)
 169 {
 170         phandle node;
 171         const void *args[] = { path };
 172         void *res[] = { &node };
 173
 174         if (olpc_ofw("finddevice", args, res)) {
 175                 pr_err("olpc_dt: finddevice failed!\n");
 176                 return 0;
 177         }
 178
 179         if ((s32) node == -1)
 180                 return 0;
 181
 182         return node;
 183 }
 184
 185 static int __init olpc_dt_interpret(const char *words)
 186 {
 187         int result;
 188         const void *args[] = { words };
 189         void *res[] = { &result };
 190
 191         if (olpc_ofw("interpret", args, res)) {
 192                 pr_err("olpc_dt: interpret failed!\n");
 193                 return -1;
 194         }
 195
 196         return result;
 197 }
 198
 199 /*
 200  * Extract board revision directly from OFW device tree.
 201  * We can't use olpc_platform_info because that hasn't been set up yet.
 202  */
 203 static u32 __init olpc_dt_get_board_revision(void)
 204 {
 205         phandle node;
 206         __be32 rev;
 207         int r;
 208
 209         node = olpc_dt_finddevice("/");
 210         if (!node)
 211                 return 0;
 212
 213         r = olpc_dt_getproperty(node, "board-revision-int",
 214                                 (char *) &rev, sizeof(rev));
 215         if (r < 0)
 216                 return 0;
 217
 218         return be32_to_cpu(rev);
 219 }
 220
 221 void __init olpc_dt_fixup(void)
 222 {
 223         int r;
 224         char buf[64];
 225         phandle node;
 226         u32 board_rev;
 227
 228         node = olpc_dt_finddevice("/battery@0");
 229         if (!node)
 230                 return;
 231
 232         /*
 233          * If the battery node has a compatible property, we are running a new
 234          * enough firmware and don't have fixups to make.
 235          */
 236         r = olpc_dt_getproperty(node, "compatible", buf, sizeof(buf));
 237         if (r > 0)
 238                 return;
 239
 240         pr_info("PROM DT: Old firmware detected, applying fixes\n");
 241
 242         /* Add olpc,xo1-battery compatible marker to battery node */
 243         olpc_dt_interpret("\" /battery@0\" find-device"
 244                 " \" olpc,xo1-battery\" +compatible"
 245                 " device-end");
 246
 247         board_rev = olpc_dt_get_board_revision();
 248         if (!board_rev)
 249                 return;
 250
 251         if (board_rev >= olpc_board_pre(0xd0)) {
 252                 /* XO-1.5: add dcon device */
 253                 olpc_dt_interpret("\" /pci/display@1\" find-device"
 254                         " new-device"
 255                         " \" dcon\" device-name \" olpc,xo1-dcon\" +compatible"
 256                         " finish-device device-end");
 257         } else {
 258                 /* XO-1: add dcon device, mark RTC as olpc,xo1-rtc */
 259                 olpc_dt_interpret("\" /pci/display@1,1\" find-device"
 260                         " new-device"
 261                         " \" dcon\" device-name \" olpc,xo1-dcon\" +compatible"
 262                         " finish-device device-end"
 263                         " \" /rtc\" find-device"
 264                         " \" olpc,xo1-rtc\" +compatible"
 265                         " device-end");
 266         }
 267 }
 268
 269 void __init olpc_dt_build_devicetree(void)
 270 {
 271         phandle root;
 272
 273         if (!olpc_ofw_is_installed())
 274                 return;
 275
 276         olpc_dt_fixup();
 277
 278         root = olpc_dt_getsibling(0);
 279         if (!root) {
 280                 pr_err("PROM: unable to get root node from OFW!\n");
 281                 return;
 282         }
 283         of_pdt_build_devicetree(root, &prom_olpc_ops);
 284
 285         pr_info("PROM DT: Built device tree with %u bytes of memory.\n",
 286                         prom_early_allocated);
 287 }
 288
 289 /* A list of DT node/bus matches that we want to expose as platform devices */
 290 static struct of_device_id __initdata of_ids[] = {
 291         { .compatible = "olpc,xo1-battery" },
 292         { .compatible = "olpc,xo1-dcon" },
 293         { .compatible = "olpc,xo1-rtc" },
 294         {},
 295 };
 296
 297 static int __init olpc_create_platform_devices(void)
 298 {
 299         if (machine_is_olpc())
 300                 return of_platform_bus_probe(NULL, of_ids, NULL);
 301         else
 302                 return 0;
 303 }
 304 device_initcall(olpc_create_platform_devices);