xref: /linux/arch/x86/platform/olpc/olpc_dt.c (revision db10cb9b) 
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 
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 
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 
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 
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 
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 
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 
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(chunk_size, SMP_CACHE_BYTES);
140 		if (!res)
141 			panic("%s: Failed to allocate %zu bytes\n", __func__,
142 			      chunk_size);
143 		BUG_ON(!res);
144 		prom_early_allocated += chunk_size;
145 		memset(res, 0, chunk_size);
146 		free_mem = chunk_size;
147 		mem = res;
148 	}
149 
150 	/* allocate from the local cache */
151 	free_mem -= size;
152 	res = mem;
153 	mem += size;
154 	return res;
155 }
156 
157 static struct of_pdt_ops prom_olpc_ops __initdata = {
158 	.nextprop = olpc_dt_nextprop,
159 	.getproplen = olpc_dt_getproplen,
160 	.getproperty = olpc_dt_getproperty,
161 	.getchild = olpc_dt_getchild,
162 	.getsibling = olpc_dt_getsibling,
163 	.pkg2path = olpc_dt_pkg2path,
164 };
165 
166 static phandle __init olpc_dt_finddevice(const char *path)
167 {
168 	phandle node;
169 	const void *args[] = { path };
170 	void *res[] = { &node };
171 
172 	if (olpc_ofw("finddevice", args, res)) {
173 		pr_err("olpc_dt: finddevice failed!\n");
174 		return 0;
175 	}
176 
177 	if ((s32) node == -1)
178 		return 0;
179 
180 	return node;
181 }
182 
183 static int __init olpc_dt_interpret(const char *words)
184 {
185 	int result;
186 	const void *args[] = { words };
187 	void *res[] = { &result };
188 
189 	if (olpc_ofw("interpret", args, res)) {
190 		pr_err("olpc_dt: interpret failed!\n");
191 		return -1;
192 	}
193 
194 	return result;
195 }
196 
197 /*
198  * Extract board revision directly from OFW device tree.
199  * We can't use olpc_platform_info because that hasn't been set up yet.
200  */
201 static u32 __init olpc_dt_get_board_revision(void)
202 {
203 	phandle node;
204 	__be32 rev;
205 	int r;
206 
207 	node = olpc_dt_finddevice("/");
208 	if (!node)
209 		return 0;
210 
211 	r = olpc_dt_getproperty(node, "board-revision-int",
212 				(char *) &rev, sizeof(rev));
213 	if (r < 0)
214 		return 0;
215 
216 	return be32_to_cpu(rev);
217 }
218 
219 static int __init olpc_dt_compatible_match(phandle node, const char *compat)
220 {
221 	char buf[64], *p;
222 	int plen, len;
223 
224 	plen = olpc_dt_getproperty(node, "compatible", buf, sizeof(buf));
225 	if (plen <= 0)
226 		return 0;
227 
228 	len = strlen(compat);
229 	for (p = buf; p < buf + plen; p += strlen(p) + 1) {
230 		if (strcmp(p, compat) == 0)
231 			return 1;
232 	}
233 
234 	return 0;
235 }
236 
237 static void __init olpc_dt_fixup(void)
238 {
239 	phandle node;
240 	u32 board_rev;
241 
242 	node = olpc_dt_finddevice("/battery@0");
243 	if (!node)
244 		return;
245 
246 	board_rev = olpc_dt_get_board_revision();
247 	if (!board_rev)
248 		return;
249 
250 	if (board_rev >= olpc_board_pre(0xd0)) {
251 		/* XO-1.5 */
252 
253 		if (olpc_dt_compatible_match(node, "olpc,xo1.5-battery"))
254 			return;
255 
256 		/* Add olpc,xo1.5-battery compatible marker to battery node */
257 		olpc_dt_interpret("\" /battery@0\" find-device");
258 		olpc_dt_interpret("  \" olpc,xo1.5-battery\" +compatible");
259 		olpc_dt_interpret("device-end");
260 
261 		if (olpc_dt_compatible_match(node, "olpc,xo1-battery")) {
262 			/*
263 			 * If we have a olpc,xo1-battery compatible, then we're
264 			 * running a new enough firmware that already has
265 			 * the dcon node.
266 			 */
267 			return;
268 		}
269 
270 		/* Add dcon device */
271 		olpc_dt_interpret("\" /pci/display@1\" find-device");
272 		olpc_dt_interpret("  new-device");
273 		olpc_dt_interpret("    \" dcon\" device-name");
274 		olpc_dt_interpret("    \" olpc,xo1-dcon\" +compatible");
275 		olpc_dt_interpret("  finish-device");
276 		olpc_dt_interpret("device-end");
277 	} else {
278 		/* XO-1 */
279 
280 		if (olpc_dt_compatible_match(node, "olpc,xo1-battery")) {
281 			/*
282 			 * If we have a olpc,xo1-battery compatible, then we're
283 			 * running a new enough firmware that already has
284 			 * the dcon and RTC nodes.
285 			 */
286 			return;
287 		}
288 
289 		/* Add dcon device, mark RTC as olpc,xo1-rtc */
290 		olpc_dt_interpret("\" /pci/display@1,1\" find-device");
291 		olpc_dt_interpret("  new-device");
292 		olpc_dt_interpret("    \" dcon\" device-name");
293 		olpc_dt_interpret("    \" olpc,xo1-dcon\" +compatible");
294 		olpc_dt_interpret("  finish-device");
295 		olpc_dt_interpret("device-end");
296 
297 		olpc_dt_interpret("\" /rtc\" find-device");
298 		olpc_dt_interpret(" \" olpc,xo1-rtc\" +compatible");
299 		olpc_dt_interpret("device-end");
300 	}
301 
302 	/* Add olpc,xo1-battery compatible marker to battery node */
303 	olpc_dt_interpret("\" /battery@0\" find-device");
304 	olpc_dt_interpret("  \" olpc,xo1-battery\" +compatible");
305 	olpc_dt_interpret("device-end");
306 }
307 
308 void __init olpc_dt_build_devicetree(void)
309 {
310 	phandle root;
311 
312 	if (!olpc_ofw_is_installed())
313 		return;
314 
315 	olpc_dt_fixup();
316 
317 	root = olpc_dt_getsibling(0);
318 	if (!root) {
319 		pr_err("PROM: unable to get root node from OFW!\n");
320 		return;
321 	}
322 	of_pdt_build_devicetree(root, &prom_olpc_ops);
323 
324 	pr_info("PROM DT: Built device tree with %u bytes of memory.\n",
325 			prom_early_allocated);
326 }
327