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 void __init olpc_dt_build_devicetree(void)
 169 {
 170         phandle root;
 171
 172         if (!olpc_ofw_is_installed())
 173                 return;
 174
 175         root = olpc_dt_getsibling(0);
 176         if (!root) {
 177                 pr_err("PROM: unable to get root node from OFW!\n");
 178                 return;
 179         }
 180         of_pdt_build_devicetree(root, &prom_olpc_ops);
 181
 182         pr_info("PROM DT: Built device tree with %u bytes of memory.\n",
 183                         prom_early_allocated);
 184 }
 185
 186 /* A list of DT node/bus matches that we want to expose as platform devices */
 187 static struct of_device_id __initdata of_ids[] = {
 188         { .compatible = "olpc,xo1-battery" },
 189         { .compatible = "olpc,xo1-dcon" },
 190         { .compatible = "olpc,xo1-rtc" },
 191         {},
 192 };
 193
 194 static int __init olpc_create_platform_devices(void)
 195 {
 196         if (machine_is_olpc())
 197                 return of_platform_bus_probe(NULL, of_ids, NULL);
 198         else
 199                 return 0;
 200 }
 201 device_initcall(olpc_create_platform_devices);