summaryrefslogtreecommitdiffstats
path: root/drivers/misc/cros_ec_lpc.c
blob: ef6e6820974c155b91ee113c419f332f15e9731c (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
/*
 * Chromium OS cros_ec driver - LPC interface
 *
 * Copyright (c) 2012 The Chromium OS Authors.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

/*
 * The Matrix Keyboard Protocol driver handles talking to the keyboard
 * controller chip. Mostly this is for keyboard functions, but some other
 * things have slipped in, so we provide generic services to talk to the
 * KBC.
 */

#include <common.h>
#include <dm.h>
#include <command.h>
#include <cros_ec.h>
#include <asm/io.h>

#ifdef DEBUG_TRACE
#define debug_trace(fmt, b...)	debug(fmt, ##b)
#else
#define debug_trace(fmt, b...)
#endif

static int wait_for_sync(struct cros_ec_dev *dev)
{
	unsigned long start;

	start = get_timer(0);
	while (inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK) {
		if (get_timer(start) > 1000) {
			debug("%s: Timeout waiting for CROS_EC sync\n",
			      __func__);
			return -1;
		}
	}

	return 0;
}

int cros_ec_lpc_command(struct udevice *udev, uint8_t cmd, int cmd_version,
		     const uint8_t *dout, int dout_len,
		     uint8_t **dinp, int din_len)
{
	struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
	const int cmd_addr = EC_LPC_ADDR_HOST_CMD;
	const int data_addr = EC_LPC_ADDR_HOST_DATA;
	const int args_addr = EC_LPC_ADDR_HOST_ARGS;
	const int param_addr = EC_LPC_ADDR_HOST_PARAM;

	struct ec_lpc_host_args args;
	uint8_t *d;
	int csum;
	int i;

	if (dout_len > EC_PROTO2_MAX_PARAM_SIZE) {
		debug("%s: Cannot send %d bytes\n", __func__, dout_len);
		return -1;
	}

	/* Fill in args */
	args.flags = EC_HOST_ARGS_FLAG_FROM_HOST;
	args.command_version = cmd_version;
	args.data_size = dout_len;

	/* Calculate checksum */
	csum = cmd + args.flags + args.command_version + args.data_size;
	for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++)
		csum += *d;

	args.checksum = (uint8_t)csum;

	if (wait_for_sync(dev)) {
		debug("%s: Timeout waiting ready\n", __func__);
		return -1;
	}

	/* Write args */
	for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++)
		outb(*d, args_addr + i);

	/* Write data, if any */
	debug_trace("cmd: %02x, ver: %02x", cmd, cmd_version);
	for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++) {
		outb(*d, param_addr + i);
		debug_trace("%02x ", *d);
	}

	outb(cmd, cmd_addr);
	debug_trace("\n");

	if (wait_for_sync(dev)) {
		debug("%s: Timeout waiting for response\n", __func__);
		return -1;
	}

	/* Check result */
	i = inb(data_addr);
	if (i) {
		debug("%s: CROS_EC result code %d\n", __func__, i);
		return -i;
	}

	/* Read back args */
	for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++)
		*d = inb(args_addr + i);

	/*
	 * If EC didn't modify args flags, then somehow we sent a new-style
	 * command to an old EC, which means it would have read its params
	 * from the wrong place.
	 */
	if (!(args.flags & EC_HOST_ARGS_FLAG_TO_HOST)) {
		debug("%s: CROS_EC protocol mismatch\n", __func__);
		return -EC_RES_INVALID_RESPONSE;
	}

	if (args.data_size > din_len) {
		debug("%s: CROS_EC returned too much data %d > %d\n",
		      __func__, args.data_size, din_len);
		return -EC_RES_INVALID_RESPONSE;
	}

	/* Read data, if any */
	for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++) {
		*d = inb(param_addr + i);
		debug_trace("%02x ", *d);
	}
	debug_trace("\n");

	/* Verify checksum */
	csum = cmd + args.flags + args.command_version + args.data_size;
	for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++)
		csum += *d;

	if (args.checksum != (uint8_t)csum) {
		debug("%s: CROS_EC response has invalid checksum\n", __func__);
		return -EC_RES_INVALID_CHECKSUM;
	}
	*dinp = dev->din;

	/* Return actual amount of data received */
	return args.data_size;
}

/**
 * Initialize LPC protocol.
 *
 * @param dev		CROS_EC device
 * @param blob		Device tree blob
 * @return 0 if ok, -1 on error
 */
int cros_ec_lpc_init(struct cros_ec_dev *dev, const void *blob)
{
	int byte, i;

	/* See if we can find an EC at the other end */
	byte = 0xff;
	byte &= inb(EC_LPC_ADDR_HOST_CMD);
	byte &= inb(EC_LPC_ADDR_HOST_DATA);
	for (i = 0; i < EC_PROTO2_MAX_PARAM_SIZE && (byte == 0xff); i++)
		byte &= inb(EC_LPC_ADDR_HOST_PARAM + i);
	if (byte == 0xff) {
		debug("%s: CROS_EC device not found on LPC bus\n",
			__func__);
		return -1;
	}

	return 0;
}

/*
 * Test if LPC command args are supported.
 *
 * The cheapest way to do this is by looking for the memory-mapped
 * flag.  This is faster than sending a new-style 'hello' command and
 * seeing whether the EC sets the EC_HOST_ARGS_FLAG_FROM_HOST flag
 * in args when it responds.
 */
static int cros_ec_lpc_check_version(struct udevice *dev)
{
	if (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) == 'E' &&
			inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1)
				== 'C' &&
			(inb(EC_LPC_ADDR_MEMMAP +
				EC_MEMMAP_HOST_CMD_FLAGS) &
				EC_HOST_CMD_FLAG_LPC_ARGS_SUPPORTED)) {
		return 0;
	}

	printf("%s: ERROR: old EC interface not supported\n", __func__);
	return -1;
}

static int cros_ec_probe(struct udevice *dev)
{
	return cros_ec_register(dev);
}

static struct dm_cros_ec_ops cros_ec_ops = {
	.command = cros_ec_lpc_command,
	.check_version = cros_ec_lpc_check_version,
};

static const struct udevice_id cros_ec_ids[] = {
	{ .compatible = "google,cros-ec" },
	{ }
};

U_BOOT_DRIVER(cros_ec_lpc) = {
	.name		= "cros_ec",
	.id		= UCLASS_CROS_EC,
	.of_match	= cros_ec_ids,
	.probe		= cros_ec_probe,
	.ops		= &cros_ec_ops,
};