1/*
2 * Support for the OLPC DCON and OLPC EC access
3 *
4 * Copyright �� 2006  Advanced Micro Devices, Inc.
5 * Copyright �� 2007-2008  Andres Salomon <dilinger@debian.org>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 */
12
13#include <linux/kernel.h>
14#include <linux/init.h>
15#include <linux/module.h>
16#include <linux/delay.h>
17#include <linux/io.h>
18#include <linux/string.h>
19#include <linux/platform_device.h>
20#include <linux/of.h>
21#include <linux/syscore_ops.h>
22#include <linux/mutex.h>
23#include <linux/olpc-ec.h>
24
25#include <asm/geode.h>
26#include <asm/setup.h>
27#include <asm/olpc.h>
28#include <asm/olpc_ofw.h>
29
30struct olpc_platform_t olpc_platform_info;
31EXPORT_SYMBOL_GPL(olpc_platform_info);
32
33/* EC event mask to be applied during suspend (defining wakeup sources). */
34static u16 ec_wakeup_mask;
35
36/* what the timeout *should* be (in ms) */
37#define EC_BASE_TIMEOUT 20
38
39/* the timeout that bugs in the EC might force us to actually use */
40static int ec_timeout = EC_BASE_TIMEOUT;
41
42static int __init olpc_ec_timeout_set(char *str)
43{
44	if (get_option(&str, &ec_timeout) != 1) {
45		ec_timeout = EC_BASE_TIMEOUT;
46		printk(KERN_ERR "olpc-ec:  invalid argument to "
47				"'olpc_ec_timeout=', ignoring!\n");
48	}
49	printk(KERN_DEBUG "olpc-ec:  using %d ms delay for EC commands.\n",
50			ec_timeout);
51	return 1;
52}
53__setup("olpc_ec_timeout=", olpc_ec_timeout_set);
54
55/*
56 * These {i,o}bf_status functions return whether the buffers are full or not.
57 */
58
59static inline unsigned int ibf_status(unsigned int port)
60{
61	return !!(inb(port) & 0x02);
62}
63
64static inline unsigned int obf_status(unsigned int port)
65{
66	return inb(port) & 0x01;
67}
68
69#define wait_on_ibf(p, d) __wait_on_ibf(__LINE__, (p), (d))
70static int __wait_on_ibf(unsigned int line, unsigned int port, int desired)
71{
72	unsigned int timeo;
73	int state = ibf_status(port);
74
75	for (timeo = ec_timeout; state != desired && timeo; timeo--) {
76		mdelay(1);
77		state = ibf_status(port);
78	}
79
80	if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
81			timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
82		printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for IBF!\n",
83				line, ec_timeout - timeo);
84	}
85
86	return !(state == desired);
87}
88
89#define wait_on_obf(p, d) __wait_on_obf(__LINE__, (p), (d))
90static int __wait_on_obf(unsigned int line, unsigned int port, int desired)
91{
92	unsigned int timeo;
93	int state = obf_status(port);
94
95	for (timeo = ec_timeout; state != desired && timeo; timeo--) {
96		mdelay(1);
97		state = obf_status(port);
98	}
99
100	if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
101			timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
102		printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for OBF!\n",
103				line, ec_timeout - timeo);
104	}
105
106	return !(state == desired);
107}
108
109/*
110 * This allows the kernel to run Embedded Controller commands.  The EC is
111 * documented at <http://wiki.laptop.org/go/Embedded_controller>, and the
112 * available EC commands are here:
113 * <http://wiki.laptop.org/go/Ec_specification>.  Unfortunately, while
114 * OpenFirmware's source is available, the EC's is not.
115 */
116static int olpc_xo1_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf,
117		size_t outlen, void *arg)
118{
119	int ret = -EIO;
120	int i;
121	int restarts = 0;
122
123	/* Clear OBF */
124	for (i = 0; i < 10 && (obf_status(0x6c) == 1); i++)
125		inb(0x68);
126	if (i == 10) {
127		printk(KERN_ERR "olpc-ec:  timeout while attempting to "
128				"clear OBF flag!\n");
129		goto err;
130	}
131
132	if (wait_on_ibf(0x6c, 0)) {
133		printk(KERN_ERR "olpc-ec:  timeout waiting for EC to "
134				"quiesce!\n");
135		goto err;
136	}
137
138restart:
139	/*
140	 * Note that if we time out during any IBF checks, that's a failure;
141	 * we have to return.  There's no way for the kernel to clear that.
142	 *
143	 * If we time out during an OBF check, we can restart the command;
144	 * reissuing it will clear the OBF flag, and we should be alright.
145	 * The OBF flag will sometimes misbehave due to what we believe
146	 * is a hardware quirk..
147	 */
148	pr_devel("olpc-ec:  running cmd 0x%x\n", cmd);
149	outb(cmd, 0x6c);
150
151	if (wait_on_ibf(0x6c, 0)) {
152		printk(KERN_ERR "olpc-ec:  timeout waiting for EC to read "
153				"command!\n");
154		goto err;
155	}
156
157	if (inbuf && inlen) {
158		/* write data to EC */
159		for (i = 0; i < inlen; i++) {
160			pr_devel("olpc-ec:  sending cmd arg 0x%x\n", inbuf[i]);
161			outb(inbuf[i], 0x68);
162			if (wait_on_ibf(0x6c, 0)) {
163				printk(KERN_ERR "olpc-ec:  timeout waiting for"
164						" EC accept data!\n");
165				goto err;
166			}
167		}
168	}
169	if (outbuf && outlen) {
170		/* read data from EC */
171		for (i = 0; i < outlen; i++) {
172			if (wait_on_obf(0x6c, 1)) {
173				printk(KERN_ERR "olpc-ec:  timeout waiting for"
174						" EC to provide data!\n");
175				if (restarts++ < 10)
176					goto restart;
177				goto err;
178			}
179			outbuf[i] = inb(0x68);
180			pr_devel("olpc-ec:  received 0x%x\n", outbuf[i]);
181		}
182	}
183
184	ret = 0;
185err:
186	return ret;
187}
188
189void olpc_ec_wakeup_set(u16 value)
190{
191	ec_wakeup_mask |= value;
192}
193EXPORT_SYMBOL_GPL(olpc_ec_wakeup_set);
194
195void olpc_ec_wakeup_clear(u16 value)
196{
197	ec_wakeup_mask &= ~value;
198}
199EXPORT_SYMBOL_GPL(olpc_ec_wakeup_clear);
200
201/*
202 * Returns true if the compile and runtime configurations allow for EC events
203 * to wake the system.
204 */
205bool olpc_ec_wakeup_available(void)
206{
207	if (!machine_is_olpc())
208		return false;
209
210	/*
211	 * XO-1 EC wakeups are available when olpc-xo1-sci driver is
212	 * compiled in
213	 */
214#ifdef CONFIG_OLPC_XO1_SCI
215	if (olpc_platform_info.boardrev < olpc_board_pre(0xd0)) /* XO-1 */
216		return true;
217#endif
218
219	/*
220	 * XO-1.5 EC wakeups are available when olpc-xo15-sci driver is
221	 * compiled in
222	 */
223#ifdef CONFIG_OLPC_XO15_SCI
224	if (olpc_platform_info.boardrev >= olpc_board_pre(0xd0)) /* XO-1.5 */
225		return true;
226#endif
227
228	return false;
229}
230EXPORT_SYMBOL_GPL(olpc_ec_wakeup_available);
231
232int olpc_ec_mask_write(u16 bits)
233{
234	if (olpc_platform_info.flags & OLPC_F_EC_WIDE_SCI) {
235		__be16 ec_word = cpu_to_be16(bits);
236		return olpc_ec_cmd(EC_WRITE_EXT_SCI_MASK, (void *) &ec_word, 2,
237				   NULL, 0);
238	} else {
239		unsigned char ec_byte = bits & 0xff;
240		return olpc_ec_cmd(EC_WRITE_SCI_MASK, &ec_byte, 1, NULL, 0);
241	}
242}
243EXPORT_SYMBOL_GPL(olpc_ec_mask_write);
244
245int olpc_ec_sci_query(u16 *sci_value)
246{
247	int ret;
248
249	if (olpc_platform_info.flags & OLPC_F_EC_WIDE_SCI) {
250		__be16 ec_word;
251		ret = olpc_ec_cmd(EC_EXT_SCI_QUERY,
252			NULL, 0, (void *) &ec_word, 2);
253		if (ret == 0)
254			*sci_value = be16_to_cpu(ec_word);
255	} else {
256		unsigned char ec_byte;
257		ret = olpc_ec_cmd(EC_SCI_QUERY, NULL, 0, &ec_byte, 1);
258		if (ret == 0)
259			*sci_value = ec_byte;
260	}
261
262	return ret;
263}
264EXPORT_SYMBOL_GPL(olpc_ec_sci_query);
265
266static bool __init check_ofw_architecture(struct device_node *root)
267{
268	const char *olpc_arch;
269	int propsize;
270
271	olpc_arch = of_get_property(root, "architecture", &propsize);
272	return propsize == 5 && strncmp("OLPC", olpc_arch, 5) == 0;
273}
274
275static u32 __init get_board_revision(struct device_node *root)
276{
277	int propsize;
278	const __be32 *rev;
279
280	rev = of_get_property(root, "board-revision-int", &propsize);
281	if (propsize != 4)
282		return 0;
283
284	return be32_to_cpu(*rev);
285}
286
287static bool __init platform_detect(void)
288{
289	struct device_node *root = of_find_node_by_path("/");
290	bool success;
291
292	if (!root)
293		return false;
294
295	success = check_ofw_architecture(root);
296	if (success) {
297		olpc_platform_info.boardrev = get_board_revision(root);
298		olpc_platform_info.flags |= OLPC_F_PRESENT;
299	}
300
301	of_node_put(root);
302	return success;
303}
304
305static int __init add_xo1_platform_devices(void)
306{
307	struct platform_device *pdev;
308
309	pdev = platform_device_register_simple("xo1-rfkill", -1, NULL, 0);
310	if (IS_ERR(pdev))
311		return PTR_ERR(pdev);
312
313	pdev = platform_device_register_simple("olpc-xo1", -1, NULL, 0);
314	if (IS_ERR(pdev))
315		return PTR_ERR(pdev);
316
317	return 0;
318}
319
320static int olpc_xo1_ec_probe(struct platform_device *pdev)
321{
322	/* get the EC revision */
323	olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0,
324			(unsigned char *) &olpc_platform_info.ecver, 1);
325
326	/* EC version 0x5f adds support for wide SCI mask */
327	if (olpc_platform_info.ecver >= 0x5f)
328		olpc_platform_info.flags |= OLPC_F_EC_WIDE_SCI;
329
330	pr_info("OLPC board revision %s%X (EC=%x)\n",
331			((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "",
332			olpc_platform_info.boardrev >> 4,
333			olpc_platform_info.ecver);
334
335	return 0;
336}
337static int olpc_xo1_ec_suspend(struct platform_device *pdev)
338{
339	olpc_ec_mask_write(ec_wakeup_mask);
340
341	/*
342	 * Squelch SCIs while suspended.  This is a fix for
343	 * <http://dev.laptop.org/ticket/1835>.
344	 */
345	return olpc_ec_cmd(EC_SET_SCI_INHIBIT, NULL, 0, NULL, 0);
346}
347
348static int olpc_xo1_ec_resume(struct platform_device *pdev)
349{
350	/* Tell the EC to stop inhibiting SCIs */
351	olpc_ec_cmd(EC_SET_SCI_INHIBIT_RELEASE, NULL, 0, NULL, 0);
352
353	/*
354	 * Tell the wireless module to restart USB communication.
355	 * Must be done twice.
356	 */
357	olpc_ec_cmd(EC_WAKE_UP_WLAN, NULL, 0, NULL, 0);
358	olpc_ec_cmd(EC_WAKE_UP_WLAN, NULL, 0, NULL, 0);
359
360	return 0;
361}
362
363static struct olpc_ec_driver ec_xo1_driver = {
364	.probe = olpc_xo1_ec_probe,
365	.suspend = olpc_xo1_ec_suspend,
366	.resume = olpc_xo1_ec_resume,
367	.ec_cmd = olpc_xo1_ec_cmd,
368};
369
370static struct olpc_ec_driver ec_xo1_5_driver = {
371	.probe = olpc_xo1_ec_probe,
372	.ec_cmd = olpc_xo1_ec_cmd,
373};
374
375static int __init olpc_init(void)
376{
377	int r = 0;
378
379	if (!olpc_ofw_present() || !platform_detect())
380		return 0;
381
382	/* register the XO-1 and 1.5-specific EC handler */
383	if (olpc_platform_info.boardrev < olpc_board_pre(0xd0))	/* XO-1 */
384		olpc_ec_driver_register(&ec_xo1_driver, NULL);
385	else
386		olpc_ec_driver_register(&ec_xo1_5_driver, NULL);
387	platform_device_register_simple("olpc-ec", -1, NULL, 0);
388
389	/* assume B1 and above models always have a DCON */
390	if (olpc_board_at_least(olpc_board(0xb1)))
391		olpc_platform_info.flags |= OLPC_F_DCON;
392
393#ifdef CONFIG_PCI_OLPC
394	/* If the VSA exists let it emulate PCI, if not emulate in kernel.
395	 * XO-1 only. */
396	if (olpc_platform_info.boardrev < olpc_board_pre(0xd0) &&
397			!cs5535_has_vsa2())
398		x86_init.pci.arch_init = pci_olpc_init;
399#endif
400
401	if (olpc_platform_info.boardrev < olpc_board_pre(0xd0)) { /* XO-1 */
402		r = add_xo1_platform_devices();
403		if (r)
404			return r;
405	}
406
407	return 0;
408}
409
410postcore_initcall(olpc_init);
411