1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * OLPC-specific OFW device tree support code.
4 *
5 * Paul Mackerras August 1996.
6 * Copyright (C) 1996-2005 Paul Mackerras.
7 *
8 * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
9 * {engebret|bergner}@us.ibm.com
10 *
11 * Adapted for sparc by David S. Miller davem@davemloft.net
12 * Adapted for x86/OLPC by Andres Salomon <dilinger@queued.net>
13 */
14
15 #include <linux/kernel.h>
16 #include <linux/memblock.h>
17 #include <linux/of.h>
18 #include <linux/of_pdt.h>
19 #include <asm/olpc.h>
20 #include <asm/olpc_ofw.h>
21
olpc_dt_getsibling(phandle node)22 static phandle __init olpc_dt_getsibling(phandle node)
23 {
24 const void *args[] = { (void *)node };
25 void *res[] = { &node };
26
27 if ((s32)node == -1)
28 return 0;
29
30 if (olpc_ofw("peer", args, res) || (s32)node == -1)
31 return 0;
32
33 return node;
34 }
35
olpc_dt_getchild(phandle node)36 static phandle __init olpc_dt_getchild(phandle node)
37 {
38 const void *args[] = { (void *)node };
39 void *res[] = { &node };
40
41 if ((s32)node == -1)
42 return 0;
43
44 if (olpc_ofw("child", args, res) || (s32)node == -1) {
45 pr_err("PROM: %s: fetching child failed!\n", __func__);
46 return 0;
47 }
48
49 return node;
50 }
51
olpc_dt_getproplen(phandle node,const char * prop)52 static int __init olpc_dt_getproplen(phandle node, const char *prop)
53 {
54 const void *args[] = { (void *)node, prop };
55 int len;
56 void *res[] = { &len };
57
58 if ((s32)node == -1)
59 return -1;
60
61 if (olpc_ofw("getproplen", args, res)) {
62 pr_err("PROM: %s: getproplen failed!\n", __func__);
63 return -1;
64 }
65
66 return len;
67 }
68
olpc_dt_getproperty(phandle node,const char * prop,char * buf,int bufsize)69 static int __init olpc_dt_getproperty(phandle node, const char *prop,
70 char *buf, int bufsize)
71 {
72 int plen;
73
74 plen = olpc_dt_getproplen(node, prop);
75 if (plen > bufsize || plen < 1) {
76 return -1;
77 } else {
78 const void *args[] = { (void *)node, prop, buf, (void *)plen };
79 void *res[] = { &plen };
80
81 if (olpc_ofw("getprop", args, res)) {
82 pr_err("PROM: %s: getprop failed!\n", __func__);
83 return -1;
84 }
85 }
86
87 return plen;
88 }
89
olpc_dt_nextprop(phandle node,char * prev,char * buf)90 static int __init olpc_dt_nextprop(phandle node, char *prev, char *buf)
91 {
92 const void *args[] = { (void *)node, prev, buf };
93 int success;
94 void *res[] = { &success };
95
96 buf[0] = '\0';
97
98 if ((s32)node == -1)
99 return -1;
100
101 if (olpc_ofw("nextprop", args, res) || success != 1)
102 return -1;
103
104 return 0;
105 }
106
olpc_dt_pkg2path(phandle node,char * buf,const int buflen,int * len)107 static int __init olpc_dt_pkg2path(phandle node, char *buf,
108 const int buflen, int *len)
109 {
110 const void *args[] = { (void *)node, buf, (void *)buflen };
111 void *res[] = { len };
112
113 if ((s32)node == -1)
114 return -1;
115
116 if (olpc_ofw("package-to-path", args, res) || *len < 1)
117 return -1;
118
119 return 0;
120 }
121
122 static unsigned int prom_early_allocated __initdata;
123
prom_early_alloc(unsigned long size)124 void * __init prom_early_alloc(unsigned long size)
125 {
126 static u8 *mem;
127 static size_t free_mem;
128 void *res;
129
130 if (free_mem < size) {
131 const size_t chunk_size = max(PAGE_SIZE, size);
132
133 /*
134 * To minimize the number of allocations, grab at least
135 * PAGE_SIZE of memory (that's an arbitrary choice that's
136 * fast enough on the platforms we care about while minimizing
137 * wasted bootmem) and hand off chunks of it to callers.
138 */
139 res = memblock_alloc_or_panic(chunk_size, SMP_CACHE_BYTES);
140 prom_early_allocated += chunk_size;
141 memset(res, 0, chunk_size);
142 free_mem = chunk_size;
143 mem = res;
144 }
145
146 /* allocate from the local cache */
147 free_mem -= size;
148 res = mem;
149 mem += size;
150 return res;
151 }
152
153 static struct of_pdt_ops prom_olpc_ops __initdata = {
154 .nextprop = olpc_dt_nextprop,
155 .getproplen = olpc_dt_getproplen,
156 .getproperty = olpc_dt_getproperty,
157 .getchild = olpc_dt_getchild,
158 .getsibling = olpc_dt_getsibling,
159 .pkg2path = olpc_dt_pkg2path,
160 };
161
olpc_dt_finddevice(const char * path)162 static phandle __init olpc_dt_finddevice(const char *path)
163 {
164 phandle node;
165 const void *args[] = { path };
166 void *res[] = { &node };
167
168 if (olpc_ofw("finddevice", args, res)) {
169 pr_err("olpc_dt: finddevice failed!\n");
170 return 0;
171 }
172
173 if ((s32) node == -1)
174 return 0;
175
176 return node;
177 }
178
olpc_dt_interpret(const char * words)179 static int __init olpc_dt_interpret(const char *words)
180 {
181 int result;
182 const void *args[] = { words };
183 void *res[] = { &result };
184
185 if (olpc_ofw("interpret", args, res)) {
186 pr_err("olpc_dt: interpret failed!\n");
187 return -1;
188 }
189
190 return result;
191 }
192
193 /*
194 * Extract board revision directly from OFW device tree.
195 * We can't use olpc_platform_info because that hasn't been set up yet.
196 */
olpc_dt_get_board_revision(void)197 static u32 __init olpc_dt_get_board_revision(void)
198 {
199 phandle node;
200 __be32 rev;
201 int r;
202
203 node = olpc_dt_finddevice("/");
204 if (!node)
205 return 0;
206
207 r = olpc_dt_getproperty(node, "board-revision-int",
208 (char *) &rev, sizeof(rev));
209 if (r < 0)
210 return 0;
211
212 return be32_to_cpu(rev);
213 }
214
olpc_dt_compatible_match(phandle node,const char * compat)215 static int __init olpc_dt_compatible_match(phandle node, const char *compat)
216 {
217 char buf[64], *p;
218 int plen;
219
220 plen = olpc_dt_getproperty(node, "compatible", buf, sizeof(buf));
221 if (plen <= 0)
222 return 0;
223
224 for (p = buf; p < buf + plen; p += strlen(p) + 1) {
225 if (strcmp(p, compat) == 0)
226 return 1;
227 }
228
229 return 0;
230 }
231
olpc_dt_fixup(void)232 static void __init olpc_dt_fixup(void)
233 {
234 phandle node;
235 u32 board_rev;
236
237 node = olpc_dt_finddevice("/battery@0");
238 if (!node)
239 return;
240
241 board_rev = olpc_dt_get_board_revision();
242 if (!board_rev)
243 return;
244
245 if (board_rev >= olpc_board_pre(0xd0)) {
246 /* XO-1.5 */
247
248 if (olpc_dt_compatible_match(node, "olpc,xo1.5-battery"))
249 return;
250
251 /* Add olpc,xo1.5-battery compatible marker to battery node */
252 olpc_dt_interpret("\" /battery@0\" find-device");
253 olpc_dt_interpret(" \" olpc,xo1.5-battery\" +compatible");
254 olpc_dt_interpret("device-end");
255
256 if (olpc_dt_compatible_match(node, "olpc,xo1-battery")) {
257 /*
258 * If we have a olpc,xo1-battery compatible, then we're
259 * running a new enough firmware that already has
260 * the dcon node.
261 */
262 return;
263 }
264
265 /* Add dcon device */
266 olpc_dt_interpret("\" /pci/display@1\" find-device");
267 olpc_dt_interpret(" new-device");
268 olpc_dt_interpret(" \" dcon\" device-name");
269 olpc_dt_interpret(" \" olpc,xo1-dcon\" +compatible");
270 olpc_dt_interpret(" finish-device");
271 olpc_dt_interpret("device-end");
272 } else {
273 /* XO-1 */
274
275 if (olpc_dt_compatible_match(node, "olpc,xo1-battery")) {
276 /*
277 * If we have a olpc,xo1-battery compatible, then we're
278 * running a new enough firmware that already has
279 * the dcon and RTC nodes.
280 */
281 return;
282 }
283
284 /* Add dcon device, mark RTC as olpc,xo1-rtc */
285 olpc_dt_interpret("\" /pci/display@1,1\" find-device");
286 olpc_dt_interpret(" new-device");
287 olpc_dt_interpret(" \" dcon\" device-name");
288 olpc_dt_interpret(" \" olpc,xo1-dcon\" +compatible");
289 olpc_dt_interpret(" finish-device");
290 olpc_dt_interpret("device-end");
291
292 olpc_dt_interpret("\" /rtc\" find-device");
293 olpc_dt_interpret(" \" olpc,xo1-rtc\" +compatible");
294 olpc_dt_interpret("device-end");
295 }
296
297 /* Add olpc,xo1-battery compatible marker to battery node */
298 olpc_dt_interpret("\" /battery@0\" find-device");
299 olpc_dt_interpret(" \" olpc,xo1-battery\" +compatible");
300 olpc_dt_interpret("device-end");
301 }
302
olpc_dt_build_devicetree(void)303 void __init olpc_dt_build_devicetree(void)
304 {
305 phandle root;
306
307 if (!olpc_ofw_is_installed())
308 return;
309
310 olpc_dt_fixup();
311
312 root = olpc_dt_getsibling(0);
313 if (!root) {
314 pr_err("PROM: unable to get root node from OFW!\n");
315 return;
316 }
317 of_pdt_build_devicetree(root, &prom_olpc_ops);
318
319 pr_info("PROM DT: Built device tree with %u bytes of memory.\n",
320 prom_early_allocated);
321 }
322