summaryrefslogtreecommitdiff
path: root/drivers/platform/chrome/cros_ec_lpc.c
blob: 3682e1539251386c658117d1b031d5c08b7fc77f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
/*
 * cros_ec_lpc - LPC access to the Chrome OS Embedded Controller
 *
 * Copyright (C) 2012-2015 Google, Inc
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * This driver uses the Chrome OS EC byte-level message-based protocol for
 * communicating the keyboard state (which keys are pressed) from a keyboard EC
 * to the AP over some bus (such as i2c, lpc, spi).  The EC does debouncing,
 * but everything else (including deghosting) is done here.  The main
 * motivation for this is to keep the EC firmware as simple as possible, since
 * it cannot be easily upgraded and EC flash/IRAM space is relatively
 * expensive.
 */

#include <linux/acpi.h>
#include <linux/dmi.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
#include <linux/mfd/cros_ec_lpc_reg.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/printk.h>
#include <linux/suspend.h>

#define DRV_NAME "cros_ec_lpcs"
#define ACPI_DRV_NAME "GOOG0004"

/* True if ACPI device is present */
static bool cros_ec_lpc_acpi_device_found;

static int ec_response_timed_out(void)
{
	unsigned long one_second = jiffies + HZ;
	u8 data;

	usleep_range(200, 300);
	do {
		if (!(cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_CMD, 1, &data) &
		    EC_LPC_STATUS_BUSY_MASK))
			return 0;
		usleep_range(100, 200);
	} while (time_before(jiffies, one_second));

	return 1;
}

static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec,
				struct cros_ec_command *msg)
{
	struct ec_host_response response;
	u8 sum;
	int ret = 0;
	u8 *dout;

	ret = cros_ec_prepare_tx(ec, msg);

	/* Write buffer */
	cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_PACKET, ret, ec->dout);

	/* Here we go */
	sum = EC_COMMAND_PROTOCOL_3;
	cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_CMD, 1, &sum);

	if (ec_response_timed_out()) {
		dev_warn(ec->dev, "EC responsed timed out\n");
		ret = -EIO;
		goto done;
	}

	/* Check result */
	msg->result = cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_DATA, 1, &sum);
	ret = cros_ec_check_result(ec, msg);
	if (ret)
		goto done;

	/* Read back response */
	dout = (u8 *)&response;
	sum = cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_PACKET, sizeof(response),
				     dout);

	msg->result = response.result;

	if (response.data_len > msg->insize) {
		dev_err(ec->dev,
			"packet too long (%d bytes, expected %d)",
			response.data_len, msg->insize);
		ret = -EMSGSIZE;
		goto done;
	}

	/* Read response and process checksum */
	sum += cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_PACKET +
				      sizeof(response), response.data_len,
				      msg->data);

	if (sum) {
		dev_err(ec->dev,
			"bad packet checksum %02x\n",
			response.checksum);
		ret = -EBADMSG;
		goto done;
	}

	/* Return actual amount of data received */
	ret = response.data_len;
done:
	return ret;
}

static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
				struct cros_ec_command *msg)
{
	struct ec_lpc_host_args args;
	u8 sum;
	int ret = 0;

	if (msg->outsize > EC_PROTO2_MAX_PARAM_SIZE ||
	    msg->insize > EC_PROTO2_MAX_PARAM_SIZE) {
		dev_err(ec->dev,
			"invalid buffer sizes (out %d, in %d)\n",
			msg->outsize, msg->insize);
		return -EINVAL;
	}

	/* Now actually send the command to the EC and get the result */
	args.flags = EC_HOST_ARGS_FLAG_FROM_HOST;
	args.command_version = msg->version;
	args.data_size = msg->outsize;

	/* Initialize checksum */
	sum = msg->command + args.flags + args.command_version + args.data_size;

	/* Copy data and update checksum */
	sum += cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_PARAM, msg->outsize,
				       msg->data);

	/* Finalize checksum and write args */
	args.checksum = sum;
	cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_ARGS, sizeof(args),
				(u8 *)&args);

	/* Here we go */
	sum = msg->command;
	cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_CMD, 1, &sum);

	if (ec_response_timed_out()) {
		dev_warn(ec->dev, "EC responsed timed out\n");
		ret = -EIO;
		goto done;
	}

	/* Check result */
	msg->result = cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_DATA, 1, &sum);
	ret = cros_ec_check_result(ec, msg);
	if (ret)
		goto done;

	/* Read back args */
	cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_ARGS, sizeof(args),
			       (u8 *)&args);

	if (args.data_size > msg->insize) {
		dev_err(ec->dev,
			"packet too long (%d bytes, expected %d)",
			args.data_size, msg->insize);
		ret = -ENOSPC;
		goto done;
	}

	/* Start calculating response checksum */
	sum = msg->command + args.flags + args.command_version + args.data_size;

	/* Read response and update checksum */
	sum += cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_PARAM, args.data_size,
				      msg->data);

	/* Verify checksum */
	if (args.checksum != sum) {
		dev_err(ec->dev,
			"bad packet checksum, expected %02x, got %02x\n",
			args.checksum, sum);
		ret = -EBADMSG;
		goto done;
	}

	/* Return actual amount of data received */
	ret = args.data_size;
done:
	return ret;
}

/* Returns num bytes read, or negative on error. Doesn't need locking. */
static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset,
			       unsigned int bytes, void *dest)
{
	int i = offset;
	char *s = dest;
	int cnt = 0;

	if (offset >= EC_MEMMAP_SIZE - bytes)
		return -EINVAL;

	/* fixed length */
	if (bytes) {
		cros_ec_lpc_read_bytes(EC_LPC_ADDR_MEMMAP + offset, bytes, s);
		return bytes;
	}

	/* string */
	for (; i < EC_MEMMAP_SIZE; i++, s++) {
		cros_ec_lpc_read_bytes(EC_LPC_ADDR_MEMMAP + i, 1, s);
		cnt++;
		if (!*s)
			break;
	}

	return cnt;
}

static void cros_ec_lpc_acpi_notify(acpi_handle device, u32 value, void *data)
{
	struct cros_ec_device *ec_dev = data;

	if (ec_dev->mkbp_event_supported &&
	    cros_ec_get_next_event(ec_dev, NULL) > 0)
		blocking_notifier_call_chain(&ec_dev->event_notifier, 0,
					     ec_dev);

	if (value == ACPI_NOTIFY_DEVICE_WAKE)
		pm_system_wakeup();
}

static int cros_ec_lpc_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct acpi_device *adev;
	acpi_status status;
	struct cros_ec_device *ec_dev;
	u8 buf[2];
	int ret;

	if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE,
				 dev_name(dev))) {
		dev_err(dev, "couldn't reserve memmap region\n");
		return -EBUSY;
	}

	cros_ec_lpc_read_bytes(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, buf);
	if (buf[0] != 'E' || buf[1] != 'C') {
		dev_err(dev, "EC ID not detected\n");
		return -ENODEV;
	}

	if (!devm_request_region(dev, EC_HOST_CMD_REGION0,
				 EC_HOST_CMD_REGION_SIZE, dev_name(dev))) {
		dev_err(dev, "couldn't reserve region0\n");
		return -EBUSY;
	}
	if (!devm_request_region(dev, EC_HOST_CMD_REGION1,
				 EC_HOST_CMD_REGION_SIZE, dev_name(dev))) {
		dev_err(dev, "couldn't reserve region1\n");
		return -EBUSY;
	}

	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
	if (!ec_dev)
		return -ENOMEM;

	platform_set_drvdata(pdev, ec_dev);
	ec_dev->dev = dev;
	ec_dev->phys_name = dev_name(dev);
	ec_dev->cmd_xfer = cros_ec_cmd_xfer_lpc;
	ec_dev->pkt_xfer = cros_ec_pkt_xfer_lpc;
	ec_dev->cmd_readmem = cros_ec_lpc_readmem;
	ec_dev->din_size = sizeof(struct ec_host_response) +
			   sizeof(struct ec_response_get_protocol_info);
	ec_dev->dout_size = sizeof(struct ec_host_request);

	ret = cros_ec_register(ec_dev);
	if (ret) {
		dev_err(dev, "couldn't register ec_dev (%d)\n", ret);
		return ret;
	}

	/*
	 * Connect a notify handler to process MKBP messages if we have a
	 * companion ACPI device.
	 */
	adev = ACPI_COMPANION(dev);
	if (adev) {
		status = acpi_install_notify_handler(adev->handle,
						     ACPI_ALL_NOTIFY,
						     cros_ec_lpc_acpi_notify,
						     ec_dev);
		if (ACPI_FAILURE(status))
			dev_warn(dev, "Failed to register notifier %08x\n",
				 status);
	}

	return 0;
}

static int cros_ec_lpc_remove(struct platform_device *pdev)
{
	struct cros_ec_device *ec_dev;
	struct acpi_device *adev;

	adev = ACPI_COMPANION(&pdev->dev);
	if (adev)
		acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
					   cros_ec_lpc_acpi_notify);

	ec_dev = platform_get_drvdata(pdev);
	cros_ec_remove(ec_dev);

	return 0;
}

static const struct acpi_device_id cros_ec_lpc_acpi_device_ids[] = {
	{ ACPI_DRV_NAME, 0 },
	{ }
};
MODULE_DEVICE_TABLE(acpi, cros_ec_lpc_acpi_device_ids);

static const struct dmi_system_id cros_ec_lpc_dmi_table[] __initconst = {
	{
		/*
		 * Today all Chromebooks/boxes ship with Google_* as version and
		 * coreboot as bios vendor. No other systems with this
		 * combination are known to date.
		 */
		.matches = {
			DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
			DMI_MATCH(DMI_BIOS_VERSION, "Google_"),
		},
	},
	{
		/*
		 * If the box is running custom coreboot firmware then the
		 * DMI BIOS version string will not be matched by "Google_",
		 * but the system vendor string will still be matched by
		 * "GOOGLE".
		 */
		.matches = {
			DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
			DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
		},
	},
	{
		/* x86-link, the Chromebook Pixel. */
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
			DMI_MATCH(DMI_PRODUCT_NAME, "Link"),
		},
	},
	{
		/* x86-samus, the Chromebook Pixel 2. */
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
			DMI_MATCH(DMI_PRODUCT_NAME, "Samus"),
		},
	},
	{
		/* x86-peppy, the Acer C720 Chromebook. */
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
			DMI_MATCH(DMI_PRODUCT_NAME, "Peppy"),
		},
	},
	{
		/* x86-glimmer, the Lenovo Thinkpad Yoga 11e. */
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
			DMI_MATCH(DMI_PRODUCT_NAME, "Glimmer"),
		},
	},
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(dmi, cros_ec_lpc_dmi_table);

#ifdef CONFIG_PM_SLEEP
static int cros_ec_lpc_suspend(struct device *dev)
{
	struct cros_ec_device *ec_dev = dev_get_drvdata(dev);

	return cros_ec_suspend(ec_dev);
}

static int cros_ec_lpc_resume(struct device *dev)
{
	struct cros_ec_device *ec_dev = dev_get_drvdata(dev);

	return cros_ec_resume(ec_dev);
}
#endif

const struct dev_pm_ops cros_ec_lpc_pm_ops = {
	SET_LATE_SYSTEM_SLEEP_PM_OPS(cros_ec_lpc_suspend, cros_ec_lpc_resume)
};

static struct platform_driver cros_ec_lpc_driver = {
	.driver = {
		.name = DRV_NAME,
		.acpi_match_table = cros_ec_lpc_acpi_device_ids,
		.pm = &cros_ec_lpc_pm_ops,
	},
	.probe = cros_ec_lpc_probe,
	.remove = cros_ec_lpc_remove,
};

static struct platform_device cros_ec_lpc_device = {
	.name = DRV_NAME
};

static acpi_status cros_ec_lpc_parse_device(acpi_handle handle, u32 level,
					    void *context, void **retval)
{
	*(bool *)context = true;
	return AE_CTRL_TERMINATE;
}

static int __init cros_ec_lpc_init(void)
{
	int ret;
	acpi_status status;

	if (!dmi_check_system(cros_ec_lpc_dmi_table)) {
		pr_err(DRV_NAME ": unsupported system.\n");
		return -ENODEV;
	}

	cros_ec_lpc_reg_init();

	/* Register the driver */
	ret = platform_driver_register(&cros_ec_lpc_driver);
	if (ret) {
		pr_err(DRV_NAME ": can't register driver: %d\n", ret);
		cros_ec_lpc_reg_destroy();
		return ret;
	}

	status = acpi_get_devices(ACPI_DRV_NAME, cros_ec_lpc_parse_device,
				  &cros_ec_lpc_acpi_device_found, NULL);
	if (ACPI_FAILURE(status))
		pr_warn(DRV_NAME ": Looking for %s failed\n", ACPI_DRV_NAME);

	if (!cros_ec_lpc_acpi_device_found) {
		/* Register the device, and it'll get hooked up automatically */
		ret = platform_device_register(&cros_ec_lpc_device);
		if (ret) {
			pr_err(DRV_NAME ": can't register device: %d\n", ret);
			platform_driver_unregister(&cros_ec_lpc_driver);
			cros_ec_lpc_reg_destroy();
		}
	}

	return ret;
}

static void __exit cros_ec_lpc_exit(void)
{
	if (!cros_ec_lpc_acpi_device_found)
		platform_device_unregister(&cros_ec_lpc_device);
	platform_driver_unregister(&cros_ec_lpc_driver);
	cros_ec_lpc_reg_destroy();
}

module_init(cros_ec_lpc_init);
module_exit(cros_ec_lpc_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ChromeOS EC LPC driver");