xref: /linux/arch/x86/platform/olpc/olpc_dt.c (revision 9c5968db9e625019a0ee5226c7eebef5519d366a)
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_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 
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 
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  */
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 
215 static int __init olpc_dt_compatible_match(phandle node, const char *compat)
216 {
217 	char buf[64], *p;
218 	int plen, len;
219 
220 	plen = olpc_dt_getproperty(node, "compatible", buf, sizeof(buf));
221 	if (plen <= 0)
222 		return 0;
223 
224 	len = strlen(compat);
225 	for (p = buf; p < buf + plen; p += strlen(p) + 1) {
226 		if (strcmp(p, compat) == 0)
227 			return 1;
228 	}
229 
230 	return 0;
231 }
232 
233 static void __init olpc_dt_fixup(void)
234 {
235 	phandle node;
236 	u32 board_rev;
237 
238 	node = olpc_dt_finddevice("/battery@0");
239 	if (!node)
240 		return;
241 
242 	board_rev = olpc_dt_get_board_revision();
243 	if (!board_rev)
244 		return;
245 
246 	if (board_rev >= olpc_board_pre(0xd0)) {
247 		/* XO-1.5 */
248 
249 		if (olpc_dt_compatible_match(node, "olpc,xo1.5-battery"))
250 			return;
251 
252 		/* Add olpc,xo1.5-battery compatible marker to battery node */
253 		olpc_dt_interpret("\" /battery@0\" find-device");
254 		olpc_dt_interpret("  \" olpc,xo1.5-battery\" +compatible");
255 		olpc_dt_interpret("device-end");
256 
257 		if (olpc_dt_compatible_match(node, "olpc,xo1-battery")) {
258 			/*
259 			 * If we have a olpc,xo1-battery compatible, then we're
260 			 * running a new enough firmware that already has
261 			 * the dcon node.
262 			 */
263 			return;
264 		}
265 
266 		/* Add dcon device */
267 		olpc_dt_interpret("\" /pci/display@1\" find-device");
268 		olpc_dt_interpret("  new-device");
269 		olpc_dt_interpret("    \" dcon\" device-name");
270 		olpc_dt_interpret("    \" olpc,xo1-dcon\" +compatible");
271 		olpc_dt_interpret("  finish-device");
272 		olpc_dt_interpret("device-end");
273 	} else {
274 		/* XO-1 */
275 
276 		if (olpc_dt_compatible_match(node, "olpc,xo1-battery")) {
277 			/*
278 			 * If we have a olpc,xo1-battery compatible, then we're
279 			 * running a new enough firmware that already has
280 			 * the dcon and RTC nodes.
281 			 */
282 			return;
283 		}
284 
285 		/* Add dcon device, mark RTC as olpc,xo1-rtc */
286 		olpc_dt_interpret("\" /pci/display@1,1\" find-device");
287 		olpc_dt_interpret("  new-device");
288 		olpc_dt_interpret("    \" dcon\" device-name");
289 		olpc_dt_interpret("    \" olpc,xo1-dcon\" +compatible");
290 		olpc_dt_interpret("  finish-device");
291 		olpc_dt_interpret("device-end");
292 
293 		olpc_dt_interpret("\" /rtc\" find-device");
294 		olpc_dt_interpret(" \" olpc,xo1-rtc\" +compatible");
295 		olpc_dt_interpret("device-end");
296 	}
297 
298 	/* Add olpc,xo1-battery compatible marker to battery node */
299 	olpc_dt_interpret("\" /battery@0\" find-device");
300 	olpc_dt_interpret("  \" olpc,xo1-battery\" +compatible");
301 	olpc_dt_interpret("device-end");
302 }
303 
304 void __init olpc_dt_build_devicetree(void)
305 {
306 	phandle root;
307 
308 	if (!olpc_ofw_is_installed())
309 		return;
310 
311 	olpc_dt_fixup();
312 
313 	root = olpc_dt_getsibling(0);
314 	if (!root) {
315 		pr_err("PROM: unable to get root node from OFW!\n");
316 		return;
317 	}
318 	of_pdt_build_devicetree(root, &prom_olpc_ops);
319 
320 	pr_info("PROM DT: Built device tree with %u bytes of memory.\n",
321 			prom_early_allocated);
322 }
323