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ec2f33ab BR |
1 | /* |
2 | * cros_ec_lpc - LPC access to the Chrome OS Embedded Controller | |
3 | * | |
4 | * Copyright (C) 2012-2015 Google, Inc | |
5 | * | |
6 | * This software is licensed under the terms of the GNU General Public | |
7 | * License version 2, as published by the Free Software Foundation, and | |
8 | * may be copied, distributed, and modified under those terms. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * This driver uses the Chrome OS EC byte-level message-based protocol for | |
16 | * communicating the keyboard state (which keys are pressed) from a keyboard EC | |
17 | * to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing, | |
18 | * but everything else (including deghosting) is done here. The main | |
19 | * motivation for this is to keep the EC firmware as simple as possible, since | |
20 | * it cannot be easily upgraded and EC flash/IRAM space is relatively | |
21 | * expensive. | |
22 | */ | |
23 | ||
24 | #include <linux/dmi.h> | |
25 | #include <linux/delay.h> | |
18d0dc24 | 26 | #include <linux/io.h> |
ec2f33ab BR |
27 | #include <linux/mfd/cros_ec.h> |
28 | #include <linux/mfd/cros_ec_commands.h> | |
29 | #include <linux/module.h> | |
30 | #include <linux/platform_device.h> | |
31 | #include <linux/printk.h> | |
32 | ||
33 | #define DRV_NAME "cros_ec_lpc" | |
34 | ||
35 | static int ec_response_timed_out(void) | |
36 | { | |
37 | unsigned long one_second = jiffies + HZ; | |
38 | ||
39 | usleep_range(200, 300); | |
40 | do { | |
41 | if (!(inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK)) | |
42 | return 0; | |
43 | usleep_range(100, 200); | |
44 | } while (time_before(jiffies, one_second)); | |
45 | ||
46 | return 1; | |
47 | } | |
48 | ||
d3654070 SB |
49 | static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec, |
50 | struct cros_ec_command *msg) | |
51 | { | |
52 | struct ec_host_request *request; | |
53 | struct ec_host_response response; | |
54 | u8 sum = 0; | |
55 | int i; | |
56 | int ret = 0; | |
57 | u8 *dout; | |
58 | ||
59 | ret = cros_ec_prepare_tx(ec, msg); | |
60 | ||
61 | /* Write buffer */ | |
62 | for (i = 0; i < ret; i++) | |
63 | outb(ec->dout[i], EC_LPC_ADDR_HOST_PACKET + i); | |
64 | ||
65 | request = (struct ec_host_request *)ec->dout; | |
66 | ||
67 | /* Here we go */ | |
68 | outb(EC_COMMAND_PROTOCOL_3, EC_LPC_ADDR_HOST_CMD); | |
69 | ||
70 | if (ec_response_timed_out()) { | |
71 | dev_warn(ec->dev, "EC responsed timed out\n"); | |
72 | ret = -EIO; | |
73 | goto done; | |
74 | } | |
75 | ||
76 | /* Check result */ | |
77 | msg->result = inb(EC_LPC_ADDR_HOST_DATA); | |
78 | ret = cros_ec_check_result(ec, msg); | |
79 | if (ret) | |
80 | goto done; | |
81 | ||
82 | /* Read back response */ | |
83 | dout = (u8 *)&response; | |
84 | for (i = 0; i < sizeof(response); i++) { | |
85 | dout[i] = inb(EC_LPC_ADDR_HOST_PACKET + i); | |
86 | sum += dout[i]; | |
87 | } | |
88 | ||
89 | msg->result = response.result; | |
90 | ||
91 | if (response.data_len > msg->insize) { | |
92 | dev_err(ec->dev, | |
93 | "packet too long (%d bytes, expected %d)", | |
94 | response.data_len, msg->insize); | |
95 | ret = -EMSGSIZE; | |
96 | goto done; | |
97 | } | |
98 | ||
99 | /* Read response and process checksum */ | |
100 | for (i = 0; i < response.data_len; i++) { | |
101 | msg->data[i] = | |
102 | inb(EC_LPC_ADDR_HOST_PACKET + sizeof(response) + i); | |
103 | sum += msg->data[i]; | |
104 | } | |
105 | ||
106 | if (sum) { | |
107 | dev_err(ec->dev, | |
108 | "bad packet checksum %02x\n", | |
109 | response.checksum); | |
110 | ret = -EBADMSG; | |
111 | goto done; | |
112 | } | |
113 | ||
114 | /* Return actual amount of data received */ | |
115 | ret = response.data_len; | |
116 | done: | |
117 | return ret; | |
118 | } | |
119 | ||
ec2f33ab BR |
120 | static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec, |
121 | struct cros_ec_command *msg) | |
122 | { | |
123 | struct ec_lpc_host_args args; | |
124 | int csum; | |
125 | int i; | |
126 | int ret = 0; | |
127 | ||
128 | if (msg->outsize > EC_PROTO2_MAX_PARAM_SIZE || | |
129 | msg->insize > EC_PROTO2_MAX_PARAM_SIZE) { | |
130 | dev_err(ec->dev, | |
131 | "invalid buffer sizes (out %d, in %d)\n", | |
132 | msg->outsize, msg->insize); | |
133 | return -EINVAL; | |
134 | } | |
135 | ||
136 | /* Now actually send the command to the EC and get the result */ | |
137 | args.flags = EC_HOST_ARGS_FLAG_FROM_HOST; | |
138 | args.command_version = msg->version; | |
139 | args.data_size = msg->outsize; | |
140 | ||
141 | /* Initialize checksum */ | |
142 | csum = msg->command + args.flags + | |
143 | args.command_version + args.data_size; | |
144 | ||
145 | /* Copy data and update checksum */ | |
146 | for (i = 0; i < msg->outsize; i++) { | |
a8411784 JMC |
147 | outb(msg->data[i], EC_LPC_ADDR_HOST_PARAM + i); |
148 | csum += msg->data[i]; | |
ec2f33ab BR |
149 | } |
150 | ||
151 | /* Finalize checksum and write args */ | |
152 | args.checksum = csum & 0xFF; | |
153 | outb(args.flags, EC_LPC_ADDR_HOST_ARGS); | |
154 | outb(args.command_version, EC_LPC_ADDR_HOST_ARGS + 1); | |
155 | outb(args.data_size, EC_LPC_ADDR_HOST_ARGS + 2); | |
156 | outb(args.checksum, EC_LPC_ADDR_HOST_ARGS + 3); | |
157 | ||
158 | /* Here we go */ | |
159 | outb(msg->command, EC_LPC_ADDR_HOST_CMD); | |
160 | ||
161 | if (ec_response_timed_out()) { | |
162 | dev_warn(ec->dev, "EC responsed timed out\n"); | |
163 | ret = -EIO; | |
164 | goto done; | |
165 | } | |
166 | ||
167 | /* Check result */ | |
168 | msg->result = inb(EC_LPC_ADDR_HOST_DATA); | |
fbf40727 JMC |
169 | ret = cros_ec_check_result(ec, msg); |
170 | if (ret) | |
ec2f33ab | 171 | goto done; |
ec2f33ab BR |
172 | |
173 | /* Read back args */ | |
174 | args.flags = inb(EC_LPC_ADDR_HOST_ARGS); | |
175 | args.command_version = inb(EC_LPC_ADDR_HOST_ARGS + 1); | |
176 | args.data_size = inb(EC_LPC_ADDR_HOST_ARGS + 2); | |
177 | args.checksum = inb(EC_LPC_ADDR_HOST_ARGS + 3); | |
178 | ||
179 | if (args.data_size > msg->insize) { | |
180 | dev_err(ec->dev, | |
181 | "packet too long (%d bytes, expected %d)", | |
182 | args.data_size, msg->insize); | |
183 | ret = -ENOSPC; | |
184 | goto done; | |
185 | } | |
186 | ||
187 | /* Start calculating response checksum */ | |
188 | csum = msg->command + args.flags + | |
189 | args.command_version + args.data_size; | |
190 | ||
191 | /* Read response and update checksum */ | |
192 | for (i = 0; i < args.data_size; i++) { | |
a8411784 JMC |
193 | msg->data[i] = inb(EC_LPC_ADDR_HOST_PARAM + i); |
194 | csum += msg->data[i]; | |
ec2f33ab BR |
195 | } |
196 | ||
197 | /* Verify checksum */ | |
198 | if (args.checksum != (csum & 0xFF)) { | |
199 | dev_err(ec->dev, | |
200 | "bad packet checksum, expected %02x, got %02x\n", | |
201 | args.checksum, csum & 0xFF); | |
202 | ret = -EBADMSG; | |
203 | goto done; | |
204 | } | |
205 | ||
206 | /* Return actual amount of data received */ | |
207 | ret = args.data_size; | |
208 | done: | |
209 | return ret; | |
210 | } | |
211 | ||
212 | /* Returns num bytes read, or negative on error. Doesn't need locking. */ | |
213 | static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset, | |
214 | unsigned int bytes, void *dest) | |
215 | { | |
216 | int i = offset; | |
217 | char *s = dest; | |
218 | int cnt = 0; | |
219 | ||
220 | if (offset >= EC_MEMMAP_SIZE - bytes) | |
221 | return -EINVAL; | |
222 | ||
223 | /* fixed length */ | |
224 | if (bytes) { | |
225 | for (; cnt < bytes; i++, s++, cnt++) | |
226 | *s = inb(EC_LPC_ADDR_MEMMAP + i); | |
227 | return cnt; | |
228 | } | |
229 | ||
230 | /* string */ | |
231 | for (; i < EC_MEMMAP_SIZE; i++, s++) { | |
232 | *s = inb(EC_LPC_ADDR_MEMMAP + i); | |
233 | cnt++; | |
234 | if (!*s) | |
235 | break; | |
236 | } | |
237 | ||
238 | return cnt; | |
239 | } | |
240 | ||
241 | static int cros_ec_lpc_probe(struct platform_device *pdev) | |
242 | { | |
243 | struct device *dev = &pdev->dev; | |
244 | struct cros_ec_device *ec_dev; | |
245 | int ret; | |
246 | ||
247 | if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE, | |
248 | dev_name(dev))) { | |
249 | dev_err(dev, "couldn't reserve memmap region\n"); | |
250 | return -EBUSY; | |
251 | } | |
252 | ||
253 | if ((inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) != 'E') || | |
254 | (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) != 'C')) { | |
255 | dev_err(dev, "EC ID not detected\n"); | |
256 | return -ENODEV; | |
257 | } | |
258 | ||
259 | if (!devm_request_region(dev, EC_HOST_CMD_REGION0, | |
260 | EC_HOST_CMD_REGION_SIZE, dev_name(dev))) { | |
261 | dev_err(dev, "couldn't reserve region0\n"); | |
262 | return -EBUSY; | |
263 | } | |
264 | if (!devm_request_region(dev, EC_HOST_CMD_REGION1, | |
265 | EC_HOST_CMD_REGION_SIZE, dev_name(dev))) { | |
266 | dev_err(dev, "couldn't reserve region1\n"); | |
267 | return -EBUSY; | |
268 | } | |
269 | ||
270 | ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); | |
271 | if (!ec_dev) | |
272 | return -ENOMEM; | |
273 | ||
274 | platform_set_drvdata(pdev, ec_dev); | |
275 | ec_dev->dev = dev; | |
ec2f33ab | 276 | ec_dev->phys_name = dev_name(dev); |
ec2f33ab | 277 | ec_dev->cmd_xfer = cros_ec_cmd_xfer_lpc; |
d3654070 | 278 | ec_dev->pkt_xfer = cros_ec_pkt_xfer_lpc; |
ec2f33ab | 279 | ec_dev->cmd_readmem = cros_ec_lpc_readmem; |
2c7589af SB |
280 | ec_dev->din_size = sizeof(struct ec_host_response) + |
281 | sizeof(struct ec_response_get_protocol_info); | |
282 | ec_dev->dout_size = sizeof(struct ec_host_request); | |
ec2f33ab BR |
283 | |
284 | ret = cros_ec_register(ec_dev); | |
285 | if (ret) { | |
286 | dev_err(dev, "couldn't register ec_dev (%d)\n", ret); | |
287 | return ret; | |
288 | } | |
289 | ||
290 | return 0; | |
291 | } | |
292 | ||
293 | static int cros_ec_lpc_remove(struct platform_device *pdev) | |
294 | { | |
295 | struct cros_ec_device *ec_dev; | |
296 | ||
297 | ec_dev = platform_get_drvdata(pdev); | |
298 | cros_ec_remove(ec_dev); | |
299 | ||
300 | return 0; | |
301 | } | |
302 | ||
303 | static struct dmi_system_id cros_ec_lpc_dmi_table[] __initdata = { | |
304 | { | |
305 | /* | |
306 | * Today all Chromebooks/boxes ship with Google_* as version and | |
307 | * coreboot as bios vendor. No other systems with this | |
308 | * combination are known to date. | |
309 | */ | |
310 | .matches = { | |
311 | DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"), | |
312 | DMI_MATCH(DMI_BIOS_VERSION, "Google_"), | |
313 | }, | |
314 | }, | |
315 | { | |
316 | /* x86-link, the Chromebook Pixel. */ | |
317 | .matches = { | |
318 | DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"), | |
319 | DMI_MATCH(DMI_PRODUCT_NAME, "Link"), | |
320 | }, | |
321 | }, | |
85bba84e JMC |
322 | { |
323 | /* x86-samus, the Chromebook Pixel 2. */ | |
324 | .matches = { | |
325 | DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"), | |
326 | DMI_MATCH(DMI_PRODUCT_NAME, "Samus"), | |
327 | }, | |
328 | }, | |
ec2f33ab BR |
329 | { |
330 | /* x86-peppy, the Acer C720 Chromebook. */ | |
331 | .matches = { | |
332 | DMI_MATCH(DMI_SYS_VENDOR, "Acer"), | |
333 | DMI_MATCH(DMI_PRODUCT_NAME, "Peppy"), | |
334 | }, | |
335 | }, | |
336 | { /* sentinel */ } | |
337 | }; | |
338 | MODULE_DEVICE_TABLE(dmi, cros_ec_lpc_dmi_table); | |
339 | ||
340 | static struct platform_driver cros_ec_lpc_driver = { | |
341 | .driver = { | |
342 | .name = DRV_NAME, | |
ec2f33ab BR |
343 | }, |
344 | .probe = cros_ec_lpc_probe, | |
345 | .remove = cros_ec_lpc_remove, | |
346 | }; | |
347 | ||
348 | static struct platform_device cros_ec_lpc_device = { | |
349 | .name = DRV_NAME | |
350 | }; | |
351 | ||
352 | static int __init cros_ec_lpc_init(void) | |
353 | { | |
354 | int ret; | |
355 | ||
356 | if (!dmi_check_system(cros_ec_lpc_dmi_table)) { | |
357 | pr_err(DRV_NAME ": unsupported system.\n"); | |
358 | return -ENODEV; | |
359 | } | |
360 | ||
361 | /* Register the driver */ | |
362 | ret = platform_driver_register(&cros_ec_lpc_driver); | |
363 | if (ret) { | |
364 | pr_err(DRV_NAME ": can't register driver: %d\n", ret); | |
365 | return ret; | |
366 | } | |
367 | ||
368 | /* Register the device, and it'll get hooked up automatically */ | |
369 | ret = platform_device_register(&cros_ec_lpc_device); | |
370 | if (ret) { | |
371 | pr_err(DRV_NAME ": can't register device: %d\n", ret); | |
372 | platform_driver_unregister(&cros_ec_lpc_driver); | |
373 | return ret; | |
374 | } | |
375 | ||
376 | return 0; | |
377 | } | |
378 | ||
379 | static void __exit cros_ec_lpc_exit(void) | |
380 | { | |
381 | platform_device_unregister(&cros_ec_lpc_device); | |
382 | platform_driver_unregister(&cros_ec_lpc_driver); | |
383 | } | |
384 | ||
385 | module_init(cros_ec_lpc_init); | |
386 | module_exit(cros_ec_lpc_exit); | |
387 | ||
388 | MODULE_LICENSE("GPL"); | |
389 | MODULE_DESCRIPTION("ChromeOS EC LPC driver"); |