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
27static 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
41static 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
57static 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
74static 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
95static 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
112static 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
127static unsigned int prom_early_allocated __initdata;
128
129void * __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
159static 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
168static 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
185static 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 */
203static 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
221void __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
269void __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 */
290static 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
297static 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}
304device_initcall(olpc_create_platform_devices);
305