xref: /openbmc/linux/arch/x86/platform/olpc/olpc_dt.c (revision 293d5b43) 
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 static phandle __init olpc_dt_finddevice(const char *path)
169 {
170 	phandle node;
171 	const void *args[] = { path };
172 	void *res[] = { &node };
173 
174 	if (olpc_ofw("finddevice", args, res)) {
175 		pr_err("olpc_dt: finddevice failed!\n");
176 		return 0;
177 	}
178 
179 	if ((s32) node == -1)
180 		return 0;
181 
182 	return node;
183 }
184 
185 static int __init olpc_dt_interpret(const char *words)
186 {
187 	int result;
188 	const void *args[] = { words };
189 	void *res[] = { &result };
190 
191 	if (olpc_ofw("interpret", args, res)) {
192 		pr_err("olpc_dt: interpret failed!\n");
193 		return -1;
194 	}
195 
196 	return result;
197 }
198 
199 /*
200  * Extract board revision directly from OFW device tree.
201  * We can't use olpc_platform_info because that hasn't been set up yet.
202  */
203 static u32 __init olpc_dt_get_board_revision(void)
204 {
205 	phandle node;
206 	__be32 rev;
207 	int r;
208 
209 	node = olpc_dt_finddevice("/");
210 	if (!node)
211 		return 0;
212 
213 	r = olpc_dt_getproperty(node, "board-revision-int",
214 				(char *) &rev, sizeof(rev));
215 	if (r < 0)
216 		return 0;
217 
218 	return be32_to_cpu(rev);
219 }
220 
221 void __init olpc_dt_fixup(void)
222 {
223 	int r;
224 	char buf[64];
225 	phandle node;
226 	u32 board_rev;
227 
228 	node = olpc_dt_finddevice("/battery@0");
229 	if (!node)
230 		return;
231 
232 	/*
233 	 * If the battery node has a compatible property, we are running a new
234 	 * enough firmware and don't have fixups to make.
235 	 */
236 	r = olpc_dt_getproperty(node, "compatible", buf, sizeof(buf));
237 	if (r > 0)
238 		return;
239 
240 	pr_info("PROM DT: Old firmware detected, applying fixes\n");
241 
242 	/* Add olpc,xo1-battery compatible marker to battery node */
243 	olpc_dt_interpret("\" /battery@0\" find-device"
244 		" \" olpc,xo1-battery\" +compatible"
245 		" device-end");
246 
247 	board_rev = olpc_dt_get_board_revision();
248 	if (!board_rev)
249 		return;
250 
251 	if (board_rev >= olpc_board_pre(0xd0)) {
252 		/* XO-1.5: add dcon device */
253 		olpc_dt_interpret("\" /pci/display@1\" find-device"
254 			" new-device"
255 			" \" dcon\" device-name \" olpc,xo1-dcon\" +compatible"
256 			" finish-device device-end");
257 	} else {
258 		/* XO-1: add dcon device, mark RTC as olpc,xo1-rtc */
259 		olpc_dt_interpret("\" /pci/display@1,1\" find-device"
260 			" new-device"
261 			" \" dcon\" device-name \" olpc,xo1-dcon\" +compatible"
262 			" finish-device device-end"
263 			" \" /rtc\" find-device"
264 			" \" olpc,xo1-rtc\" +compatible"
265 			" device-end");
266 	}
267 }
268 
269 void __init olpc_dt_build_devicetree(void)
270 {
271 	phandle root;
272 
273 	if (!olpc_ofw_is_installed())
274 		return;
275 
276 	olpc_dt_fixup();
277 
278 	root = olpc_dt_getsibling(0);
279 	if (!root) {
280 		pr_err("PROM: unable to get root node from OFW!\n");
281 		return;
282 	}
283 	of_pdt_build_devicetree(root, &prom_olpc_ops);
284 
285 	pr_info("PROM DT: Built device tree with %u bytes of memory.\n",
286 			prom_early_allocated);
287 }
288 
289 /* A list of DT node/bus matches that we want to expose as platform devices */
290 static struct of_device_id __initdata of_ids[] = {
291 	{ .compatible = "olpc,xo1-battery" },
292 	{ .compatible = "olpc,xo1-dcon" },
293 	{ .compatible = "olpc,xo1-rtc" },
294 	{},
295 };
296 
297 static int __init olpc_create_platform_devices(void)
298 {
299 	if (machine_is_olpc())
300 		return of_platform_bus_probe(NULL, of_ids, NULL);
301 	else
302 		return 0;
303 }
304 device_initcall(olpc_create_platform_devices);
305