platform/olpc/olpc_dt.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * OLPC-specific OFW device tree support code.
0004  *
0005  * Paul Mackerras   August 1996.
0006  * Copyright (C) 1996-2005 Paul Mackerras.
0007  *
0008  *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
0009  *    {engebret|bergner}@us.ibm.com
0010  *
0011  *  Adapted for sparc by David S. Miller davem@davemloft.net
0012  *  Adapted for x86/OLPC by Andres Salomon <dilinger@queued.net>
0013  */
0014
0015 #include <linux/kernel.h>
0016 #include <linux/memblock.h>
0017 #include <linux/of.h>
0018 #include <linux/of_pdt.h>
0019 #include <asm/olpc.h>
0020 #include <asm/olpc_ofw.h>
0021
0022 static phandle __init olpc_dt_getsibling(phandle node)
0023 {
0024     const void *args[] = { (void *)node };
0025     void *res[] = { &node };
0026
0027     if ((s32)node == -1)
0028         return 0;
0029
0030     if (olpc_ofw("peer", args, res) || (s32)node == -1)
0031         return 0;
0032
0033     return node;
0034 }
0035
0036 static phandle __init olpc_dt_getchild(phandle node)
0037 {
0038     const void *args[] = { (void *)node };
0039     void *res[] = { &node };
0040
0041     if ((s32)node == -1)
0042         return 0;
0043
0044     if (olpc_ofw("child", args, res) || (s32)node == -1) {
0045         pr_err("PROM: %s: fetching child failed!\n", __func__);
0046         return 0;
0047     }
0048
0049     return node;
0050 }
0051
0052 static int __init olpc_dt_getproplen(phandle node, const char *prop)
0053 {
0054     const void *args[] = { (void *)node, prop };
0055     int len;
0056     void *res[] = { &len };
0057
0058     if ((s32)node == -1)
0059         return -1;
0060
0061     if (olpc_ofw("getproplen", args, res)) {
0062         pr_err("PROM: %s: getproplen failed!\n", __func__);
0063         return -1;
0064     }
0065
0066     return len;
0067 }
0068
0069 static int __init olpc_dt_getproperty(phandle node, const char *prop,
0070         char *buf, int bufsize)
0071 {
0072     int plen;
0073
0074     plen = olpc_dt_getproplen(node, prop);
0075     if (plen > bufsize || plen < 1) {
0076         return -1;
0077     } else {
0078         const void *args[] = { (void *)node, prop, buf, (void *)plen };
0079         void *res[] = { &plen };
0080
0081         if (olpc_ofw("getprop", args, res)) {
0082             pr_err("PROM: %s: getprop failed!\n", __func__);
0083             return -1;
0084         }
0085     }
0086
0087     return plen;
0088 }
0089
0090 static int __init olpc_dt_nextprop(phandle node, char *prev, char *buf)
0091 {
0092     const void *args[] = { (void *)node, prev, buf };
0093     int success;
0094     void *res[] = { &success };
0095
0096     buf[0] = '\0';
0097
0098     if ((s32)node == -1)
0099         return -1;
0100
0101     if (olpc_ofw("nextprop", args, res) || success != 1)
0102         return -1;
0103
0104     return 0;
0105 }
0106
0107 static int __init olpc_dt_pkg2path(phandle node, char *buf,
0108         const int buflen, int *len)
0109 {
0110     const void *args[] = { (void *)node, buf, (void *)buflen };
0111     void *res[] = { len };
0112
0113     if ((s32)node == -1)
0114         return -1;
0115
0116     if (olpc_ofw("package-to-path", args, res) || *len < 1)
0117         return -1;
0118
0119     return 0;
0120 }
0121
0122 static unsigned int prom_early_allocated __initdata;
0123
0124 void * __init prom_early_alloc(unsigned long size)
0125 {
0126     static u8 *mem;
0127     static size_t free_mem;
0128     void *res;
0129
0130     if (free_mem < size) {
0131         const size_t chunk_size = max(PAGE_SIZE, size);
0132
0133         /*
0134          * To minimize the number of allocations, grab at least
0135          * PAGE_SIZE of memory (that's an arbitrary choice that's
0136          * fast enough on the platforms we care about while minimizing
0137          * wasted bootmem) and hand off chunks of it to callers.
0138          */
0139         res = memblock_alloc(chunk_size, SMP_CACHE_BYTES);
0140         if (!res)
0141             panic("%s: Failed to allocate %zu bytes\n", __func__,
0142                   chunk_size);
0143         BUG_ON(!res);
0144         prom_early_allocated += chunk_size;
0145         memset(res, 0, chunk_size);
0146         free_mem = chunk_size;
0147         mem = res;
0148     }
0149
0150     /* allocate from the local cache */
0151     free_mem -= size;
0152     res = mem;
0153     mem += size;
0154     return res;
0155 }
0156
0157 static struct of_pdt_ops prom_olpc_ops __initdata = {
0158     .nextprop = olpc_dt_nextprop,
0159     .getproplen = olpc_dt_getproplen,
0160     .getproperty = olpc_dt_getproperty,
0161     .getchild = olpc_dt_getchild,
0162     .getsibling = olpc_dt_getsibling,
0163     .pkg2path = olpc_dt_pkg2path,
0164 };
0165
0166 static phandle __init olpc_dt_finddevice(const char *path)
0167 {
0168     phandle node;
0169     const void *args[] = { path };
0170     void *res[] = { &node };
0171
0172     if (olpc_ofw("finddevice", args, res)) {
0173         pr_err("olpc_dt: finddevice failed!\n");
0174         return 0;
0175     }
0176
0177     if ((s32) node == -1)
0178         return 0;
0179
0180     return node;
0181 }
0182
0183 static int __init olpc_dt_interpret(const char *words)
0184 {
0185     int result;
0186     const void *args[] = { words };
0187     void *res[] = { &result };
0188
0189     if (olpc_ofw("interpret", args, res)) {
0190         pr_err("olpc_dt: interpret failed!\n");
0191         return -1;
0192     }
0193
0194     return result;
0195 }
0196
0197 /*
0198  * Extract board revision directly from OFW device tree.
0199  * We can't use olpc_platform_info because that hasn't been set up yet.
0200  */
0201 static u32 __init olpc_dt_get_board_revision(void)
0202 {
0203     phandle node;
0204     __be32 rev;
0205     int r;
0206
0207     node = olpc_dt_finddevice("/");
0208     if (!node)
0209         return 0;
0210
0211     r = olpc_dt_getproperty(node, "board-revision-int",
0212                 (char *) &rev, sizeof(rev));
0213     if (r < 0)
0214         return 0;
0215
0216     return be32_to_cpu(rev);
0217 }
0218
0219 static int __init olpc_dt_compatible_match(phandle node, const char *compat)
0220 {
0221     char buf[64], *p;
0222     int plen, len;
0223
0224     plen = olpc_dt_getproperty(node, "compatible", buf, sizeof(buf));
0225     if (plen <= 0)
0226         return 0;
0227
0228     len = strlen(compat);
0229     for (p = buf; p < buf + plen; p += strlen(p) + 1) {
0230         if (strcmp(p, compat) == 0)
0231             return 1;
0232     }
0233
0234     return 0;
0235 }
0236
0237 void __init olpc_dt_fixup(void)
0238 {
0239     phandle node;
0240     u32 board_rev;
0241
0242     node = olpc_dt_finddevice("/battery@0");
0243     if (!node)
0244         return;
0245
0246     board_rev = olpc_dt_get_board_revision();
0247     if (!board_rev)
0248         return;
0249
0250     if (board_rev >= olpc_board_pre(0xd0)) {
0251         /* XO-1.5 */
0252
0253         if (olpc_dt_compatible_match(node, "olpc,xo1.5-battery"))
0254             return;
0255
0256         /* Add olpc,xo1.5-battery compatible marker to battery node */
0257         olpc_dt_interpret("\" /battery@0\" find-device");
0258         olpc_dt_interpret("  \" olpc,xo1.5-battery\" +compatible");
0259         olpc_dt_interpret("device-end");
0260
0261         if (olpc_dt_compatible_match(node, "olpc,xo1-battery")) {
0262             /*
0263              * If we have a olpc,xo1-battery compatible, then we're
0264              * running a new enough firmware that already has
0265              * the dcon node.
0266              */
0267             return;
0268         }
0269
0270         /* Add dcon device */
0271         olpc_dt_interpret("\" /pci/display@1\" find-device");
0272         olpc_dt_interpret("  new-device");
0273         olpc_dt_interpret("    \" dcon\" device-name");
0274         olpc_dt_interpret("    \" olpc,xo1-dcon\" +compatible");
0275         olpc_dt_interpret("  finish-device");
0276         olpc_dt_interpret("device-end");
0277     } else {
0278         /* XO-1 */
0279
0280         if (olpc_dt_compatible_match(node, "olpc,xo1-battery")) {
0281             /*
0282              * If we have a olpc,xo1-battery compatible, then we're
0283              * running a new enough firmware that already has
0284              * the dcon and RTC nodes.
0285              */
0286             return;
0287         }
0288
0289         /* Add dcon device, mark RTC as olpc,xo1-rtc */
0290         olpc_dt_interpret("\" /pci/display@1,1\" find-device");
0291         olpc_dt_interpret("  new-device");
0292         olpc_dt_interpret("    \" dcon\" device-name");
0293         olpc_dt_interpret("    \" olpc,xo1-dcon\" +compatible");
0294         olpc_dt_interpret("  finish-device");
0295         olpc_dt_interpret("device-end");
0296
0297         olpc_dt_interpret("\" /rtc\" find-device");
0298         olpc_dt_interpret(" \" olpc,xo1-rtc\" +compatible");
0299         olpc_dt_interpret("device-end");
0300     }
0301
0302     /* Add olpc,xo1-battery compatible marker to battery node */
0303     olpc_dt_interpret("\" /battery@0\" find-device");
0304     olpc_dt_interpret("  \" olpc,xo1-battery\" +compatible");
0305     olpc_dt_interpret("device-end");
0306 }
0307
0308 void __init olpc_dt_build_devicetree(void)
0309 {
0310     phandle root;
0311
0312     if (!olpc_ofw_is_installed())
0313         return;
0314
0315     olpc_dt_fixup();
0316
0317     root = olpc_dt_getsibling(0);
0318     if (!root) {
0319         pr_err("PROM: unable to get root node from OFW!\n");
0320         return;
0321     }
0322     of_pdt_build_devicetree(root, &prom_olpc_ops);
0323
0324     pr_info("PROM DT: Built device tree with %u bytes of memory.\n",
0325             prom_early_allocated);
0326 }