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/spinlock.h>
18 #include <linux/io.h>
19 #include <linux/string.h>
20 #include <linux/platform_device.h>
21
22 #include <asm/geode.h>
23 #include <asm/setup.h>
24 #include <asm/olpc.h>
25 #include <asm/olpc_ofw.h>
26
27 struct olpc_platform_t olpc_platform_info;
28 EXPORT_SYMBOL_GPL(olpc_platform_info);
29
30 static DEFINE_SPINLOCK(ec_lock);
31
32 /* what the timeout *should* be (in ms) */
33 #define EC_BASE_TIMEOUT 20
34
35 /* the timeout that bugs in the EC might force us to actually use */
36 static int ec_timeout = EC_BASE_TIMEOUT;
37
olpc_ec_timeout_set(char * str)38 static int __init olpc_ec_timeout_set(char *str)
39 {
40 if (get_option(&str, &ec_timeout) != 1) {
41 ec_timeout = EC_BASE_TIMEOUT;
42 printk(KERN_ERR "olpc-ec: invalid argument to "
43 "'olpc_ec_timeout=', ignoring!\n");
44 }
45 printk(KERN_DEBUG "olpc-ec: using %d ms delay for EC commands.\n",
46 ec_timeout);
47 return 1;
48 }
49 __setup("olpc_ec_timeout=", olpc_ec_timeout_set);
50
51 /*
52 * These {i,o}bf_status functions return whether the buffers are full or not.
53 */
54
ibf_status(unsigned int port)55 static inline unsigned int ibf_status(unsigned int port)
56 {
57 return !!(inb(port) & 0x02);
58 }
59
obf_status(unsigned int port)60 static inline unsigned int obf_status(unsigned int port)
61 {
62 return inb(port) & 0x01;
63 }
64
65 #define wait_on_ibf(p, d) __wait_on_ibf(__LINE__, (p), (d))
__wait_on_ibf(unsigned int line,unsigned int port,int desired)66 static int __wait_on_ibf(unsigned int line, unsigned int port, int desired)
67 {
68 unsigned int timeo;
69 int state = ibf_status(port);
70
71 for (timeo = ec_timeout; state != desired && timeo; timeo--) {
72 mdelay(1);
73 state = ibf_status(port);
74 }
75
76 if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
77 timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
78 printk(KERN_WARNING "olpc-ec: %d: waited %u ms for IBF!\n",
79 line, ec_timeout - timeo);
80 }
81
82 return !(state == desired);
83 }
84
85 #define wait_on_obf(p, d) __wait_on_obf(__LINE__, (p), (d))
__wait_on_obf(unsigned int line,unsigned int port,int desired)86 static int __wait_on_obf(unsigned int line, unsigned int port, int desired)
87 {
88 unsigned int timeo;
89 int state = obf_status(port);
90
91 for (timeo = ec_timeout; state != desired && timeo; timeo--) {
92 mdelay(1);
93 state = obf_status(port);
94 }
95
96 if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
97 timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
98 printk(KERN_WARNING "olpc-ec: %d: waited %u ms for OBF!\n",
99 line, ec_timeout - timeo);
100 }
101
102 return !(state == desired);
103 }
104
105 /*
106 * This allows the kernel to run Embedded Controller commands. The EC is
107 * documented at <http://wiki.laptop.org/go/Embedded_controller>, and the
108 * available EC commands are here:
109 * <http://wiki.laptop.org/go/Ec_specification>. Unfortunately, while
110 * OpenFirmware's source is available, the EC's is not.
111 */
olpc_ec_cmd(unsigned char cmd,unsigned char * inbuf,size_t inlen,unsigned char * outbuf,size_t outlen)112 int olpc_ec_cmd(unsigned char cmd, unsigned char *inbuf, size_t inlen,
113 unsigned char *outbuf, size_t outlen)
114 {
115 unsigned long flags;
116 int ret = -EIO;
117 int i;
118 int restarts = 0;
119
120 spin_lock_irqsave(&ec_lock, flags);
121
122 /* Clear OBF */
123 for (i = 0; i < 10 && (obf_status(0x6c) == 1); i++)
124 inb(0x68);
125 if (i == 10) {
126 printk(KERN_ERR "olpc-ec: timeout while attempting to "
127 "clear OBF flag!\n");
128 goto err;
129 }
130
131 if (wait_on_ibf(0x6c, 0)) {
132 printk(KERN_ERR "olpc-ec: timeout waiting for EC to "
133 "quiesce!\n");
134 goto err;
135 }
136
137 restart:
138 /*
139 * Note that if we time out during any IBF checks, that's a failure;
140 * we have to return. There's no way for the kernel to clear that.
141 *
142 * If we time out during an OBF check, we can restart the command;
143 * reissuing it will clear the OBF flag, and we should be alright.
144 * The OBF flag will sometimes misbehave due to what we believe
145 * is a hardware quirk..
146 */
147 pr_devel("olpc-ec: running cmd 0x%x\n", cmd);
148 outb(cmd, 0x6c);
149
150 if (wait_on_ibf(0x6c, 0)) {
151 printk(KERN_ERR "olpc-ec: timeout waiting for EC to read "
152 "command!\n");
153 goto err;
154 }
155
156 if (inbuf && inlen) {
157 /* write data to EC */
158 for (i = 0; i < inlen; i++) {
159 if (wait_on_ibf(0x6c, 0)) {
160 printk(KERN_ERR "olpc-ec: timeout waiting for"
161 " EC accept data!\n");
162 goto err;
163 }
164 pr_devel("olpc-ec: sending cmd arg 0x%x\n", inbuf[i]);
165 outb(inbuf[i], 0x68);
166 }
167 }
168 if (outbuf && outlen) {
169 /* read data from EC */
170 for (i = 0; i < outlen; i++) {
171 if (wait_on_obf(0x6c, 1)) {
172 printk(KERN_ERR "olpc-ec: timeout waiting for"
173 " EC to provide data!\n");
174 if (restarts++ < 10)
175 goto restart;
176 goto err;
177 }
178 outbuf[i] = inb(0x68);
179 pr_devel("olpc-ec: received 0x%x\n", outbuf[i]);
180 }
181 }
182
183 ret = 0;
184 err:
185 spin_unlock_irqrestore(&ec_lock, flags);
186 return ret;
187 }
188 EXPORT_SYMBOL_GPL(olpc_ec_cmd);
189
check_ofw_architecture(void)190 static bool __init check_ofw_architecture(void)
191 {
192 size_t propsize;
193 char olpc_arch[5];
194 const void *args[] = { NULL, "architecture", olpc_arch, (void *)5 };
195 void *res[] = { &propsize };
196
197 if (olpc_ofw("getprop", args, res)) {
198 printk(KERN_ERR "ofw: getprop call failed!\n");
199 return false;
200 }
201 return propsize == 5 && strncmp("OLPC", olpc_arch, 5) == 0;
202 }
203
get_board_revision(void)204 static u32 __init get_board_revision(void)
205 {
206 size_t propsize;
207 __be32 rev;
208 const void *args[] = { NULL, "board-revision-int", &rev, (void *)4 };
209 void *res[] = { &propsize };
210
211 if (olpc_ofw("getprop", args, res) || propsize != 4) {
212 printk(KERN_ERR "ofw: getprop call failed!\n");
213 return cpu_to_be32(0);
214 }
215 return be32_to_cpu(rev);
216 }
217
platform_detect(void)218 static bool __init platform_detect(void)
219 {
220 if (!check_ofw_architecture())
221 return false;
222 olpc_platform_info.flags |= OLPC_F_PRESENT;
223 olpc_platform_info.boardrev = get_board_revision();
224 return true;
225 }
226
add_xo1_platform_devices(void)227 static int __init add_xo1_platform_devices(void)
228 {
229 struct platform_device *pdev;
230
231 pdev = platform_device_register_simple("xo1-rfkill", -1, NULL, 0);
232 if (IS_ERR(pdev))
233 return PTR_ERR(pdev);
234
235 pdev = platform_device_register_simple("olpc-xo1", -1, NULL, 0);
236 if (IS_ERR(pdev))
237 return PTR_ERR(pdev);
238
239 return 0;
240 }
241
olpc_init(void)242 static int __init olpc_init(void)
243 {
244 int r = 0;
245
246 if (!olpc_ofw_present() || !platform_detect())
247 return 0;
248
249 spin_lock_init(&ec_lock);
250
251 /* assume B1 and above models always have a DCON */
252 if (olpc_board_at_least(olpc_board(0xb1)))
253 olpc_platform_info.flags |= OLPC_F_DCON;
254
255 /* get the EC revision */
256 olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0,
257 (unsigned char *) &olpc_platform_info.ecver, 1);
258
259 #ifdef CONFIG_PCI_OLPC
260 /* If the VSA exists let it emulate PCI, if not emulate in kernel.
261 * XO-1 only. */
262 if (olpc_platform_info.boardrev < olpc_board_pre(0xd0) &&
263 !cs5535_has_vsa2())
264 x86_init.pci.arch_init = pci_olpc_init;
265 #endif
266
267 printk(KERN_INFO "OLPC board revision %s%X (EC=%x)\n",
268 ((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "",
269 olpc_platform_info.boardrev >> 4,
270 olpc_platform_info.ecver);
271
272 if (olpc_platform_info.boardrev < olpc_board_pre(0xd0)) { /* XO-1 */
273 r = add_xo1_platform_devices();
274 if (r)
275 return r;
276 }
277
278 return 0;
279 }
280
281 postcore_initcall(olpc_init);
282