summaryrefslogtreecommitdiff
path: root/src/ec/google/chromeec/ec_i2c.c
blob: 2eecced7219a7900aa035e088866813609678e92 (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
/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2013 Google Inc.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License
 *
 * 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.
 */

#include <console/console.h>
#include <delay.h>
#include <device/i2c_simple.h>
#include <stdint.h>
#include <string.h>

#include "ec.h"
#include "ec_commands.h"

#if CONFIG(EC_GOOGLE_CHROMEEC_I2C_PROTO3)

#define PROTO3_FRAMING_BYTES sizeof(uint32_t)
/* Just use the LPC host packet size to size the buffer. */
#define PROTO3_MAX_PACKET_SIZE 268

struct proto3_i2c_buf {
	uint8_t framing_bytes[PROTO3_FRAMING_BYTES];
	uint8_t data[PROTO3_MAX_PACKET_SIZE];
} __attribute__((aligned(sizeof(uint32_t))));

static struct proto3_i2c_buf req_buf;
static struct proto3_i2c_buf resp_buf;

enum {
	CMD_INDEX,
	RESP_INDEX,
	SEGS_PER_CMD,
};

struct i2c_ec {
	int bus;
	struct i2c_msg segs[SEGS_PER_CMD];
};

static struct i2c_ec ec_dev = {
	.bus = CONFIG_EC_GOOGLE_CHROMEEC_I2C_BUS,
	.segs[CMD_INDEX] = {
		.flags = 0,
		.slave = CONFIG_EC_GOOGLE_CHROMEEC_I2C_CHIP,
		/* Framing byte to be transferred prior to request. */
		.buf = &req_buf.framing_bytes[3],
	},
	.segs[RESP_INDEX] = {
		.flags = I2C_M_RD,
		.slave = CONFIG_EC_GOOGLE_CHROMEEC_I2C_CHIP,
		/* return code and total length before full response. */
		.buf = &resp_buf.framing_bytes[2],
	},
};

void *crosec_get_buffer(size_t size, int req)
{
	struct proto3_i2c_buf *ib;

	if (size > PROTO3_MAX_PACKET_SIZE) {
		printk(BIOS_DEBUG, "Proto v3 buffer request too large: %zu!\n",
			size);
		return NULL;
	}

	if (req)
		ib = &req_buf;
	else
		ib = &resp_buf;

	return &ib->data[0];
}

static int crosec_i2c_io(size_t req_size, size_t resp_size, void *context)
{
	struct i2c_ec *ec = context;
	uint8_t ret_code;
	size_t resp_len;

	if (req_size > PROTO3_MAX_PACKET_SIZE ||
		resp_size > PROTO3_MAX_PACKET_SIZE)
		return -1;

	/* Place the framing byte and set size accordingly. */
	ec->segs[CMD_INDEX].len = req_size + 1;
	ec->segs[CMD_INDEX].buf[0] = EC_COMMAND_PROTOCOL_3;
	/* Return code and length returned prior to packet data. */
	ec->segs[RESP_INDEX].len = resp_size + 2;

	if (i2c_transfer(ec->bus, ec->segs, ARRAY_SIZE(ec->segs)) != 0) {
		printk(BIOS_ERR, "%s: Cannot complete read from i2c-%d:%#x\n",
		       __func__, ec->bus, ec->segs[0].slave);
		return -1;
	}

	ret_code = ec->segs[RESP_INDEX].buf[0];
	resp_len = ec->segs[RESP_INDEX].buf[1];

	if (ret_code != 0) {
		printk(BIOS_ERR, "EC command returned 0x%x\n", ret_code);
		return -1;
	}

	if (resp_len > resp_size) {
		printk(BIOS_ERR, "Response length mismatch %zu vs %zu\n",
			resp_len, resp_size);
		return -1;
	}

	return 0;
}

int google_chromeec_command(struct chromeec_command *cec_command)
{
	return crosec_command_proto(cec_command, crosec_i2c_io, &ec_dev);
}

#else /* CONFIG_EC_GOOGLE_CHROMEEC_I2C_PROTO3 */

/* Command (host->device) format for I2C:
 *  uint8_t version, cmd, len, data[len], checksum;
 *
 * Response (device->host) format for I2C:
 *  uint8_t response, len, data[len], checksum;
 *
 * Note the location of checksum is different from LPC protocol.
 *
 * The length is 8 bit so maximum data size is 0xff.
 * Any I2C command should fit in 0xff + 4 bytes, and max response length
 * is 0xff + 3 bytes.
 */
#define MAX_I2C_DATA_SIZE		(0xff)

typedef struct {
	uint8_t version;
	uint8_t command;
	uint8_t length;
	uint8_t data[MAX_I2C_DATA_SIZE + 1];
} EcCommandI2c;

typedef struct {
	uint8_t response;
	uint8_t length;
	uint8_t data[MAX_I2C_DATA_SIZE + 1];
} EcResponseI2c;

static inline void i2c_dump(int bus, int chip, const uint8_t *data, size_t size)
{
#ifdef TRACE_CHROMEEC
	printk(BIOS_INFO, "i2c: bus=%d, chip=%#x, size=%d, data: ", bus, chip,
	       size);
	while (size-- > 0) {
		printk(BIOS_INFO, "%02X ", *data++);
	}
	printk(BIOS_INFO, "\n");
#endif
}

static int ec_verify_checksum(const EcResponseI2c *resp)
{
	size_t size = sizeof(*resp) - sizeof(resp->data) + resp->length;
	uint8_t calculated = google_chromeec_calc_checksum(
			(const uint8_t *)resp, size);
	uint8_t received = resp->data[resp->length];
	if (calculated != received) {
		printk(BIOS_ERR, "%s: Unmatch (rx: %#02x, calc: %#02x)\n",
		       __func__, received, calculated);
		return 0;
	}
	return 1;
}

static void ec_fill_checksum(EcCommandI2c *cmd)
{
	size_t size = sizeof(*cmd) - sizeof(cmd->data) + cmd->length;
	cmd->data[cmd->length] = google_chromeec_calc_checksum(
			(const uint8_t *)cmd, size);
}

int google_chromeec_command(struct chromeec_command *cec_command)
{
	EcCommandI2c cmd;
	EcResponseI2c resp;
	int bus = CONFIG_EC_GOOGLE_CHROMEEC_I2C_BUS;
	int chip = CONFIG_EC_GOOGLE_CHROMEEC_I2C_CHIP;
	size_t size_i2c_cmd = (sizeof(cmd) - sizeof(cmd.data) +
			       cec_command->cmd_size_in + 1),
	       size_i2c_resp = (sizeof(resp) - sizeof(resp.data) +
				cec_command->cmd_size_out + 1);

	if (cec_command->cmd_size_in > MAX_I2C_DATA_SIZE ||
	    cec_command->cmd_size_out > MAX_I2C_DATA_SIZE) {
		printk(BIOS_ERR, "%s: Command data size too large (%d,%d)\n",
		       __func__, cec_command->cmd_size_in,
		       cec_command->cmd_size_out);
		cec_command->cmd_code = EC_RES_INVALID_PARAM;
		return 1;
	}

	/* Construct command. */
	cmd.version = EC_CMD_VERSION0 + cec_command->cmd_version;
	cmd.command = cec_command->cmd_code;
	cmd.length = cec_command->cmd_size_in;
	memcpy(cmd.data, cec_command->cmd_data_in, cmd.length);
	ec_fill_checksum(&cmd);

	/* Start I2C communication */
	i2c_dump(bus, chip, (const uint8_t *)&cmd, size_i2c_cmd);
	if (i2c_write_raw(bus, chip, (uint8_t *)&cmd, size_i2c_cmd) != 0) {
		printk(BIOS_ERR, "%s: Cannot complete write to i2c-%d:%#x\n",
		       __func__, bus, chip);
		cec_command->cmd_code = EC_RES_ERROR;
		return 1;
	}
	if (i2c_read_raw(bus, chip, (uint8_t *)&resp, size_i2c_resp) != 0) {
		printk(BIOS_ERR, "%s: Cannot complete read from i2c-%d:%#x\n",
		       __func__, bus, chip);
		cec_command->cmd_code = EC_RES_ERROR;
		return 1;
	}

	/* Verify and return response */
	cec_command->cmd_code = resp.response;
	if (resp.response != EC_RES_SUCCESS) {
		printk(BIOS_DEBUG, "%s: Received bad result code %d\n",
		       __func__, (int)resp.response);
		return 1;
	}
	if (resp.length > cec_command->cmd_size_out) {
		printk(BIOS_ERR, "%s: Received len %#02x too large\n",
		       __func__, (int)resp.length);
		cec_command->cmd_code = EC_RES_INVALID_RESPONSE;
		return 1;
	}
	if (!ec_verify_checksum(&resp)) {
		cec_command->cmd_code = EC_RES_INVALID_CHECKSUM;
		return 1;
	}
	cec_command->cmd_size_out = resp.length;
	memcpy(cec_command->cmd_data_out, resp.data, resp.length);
	return 0;
}

#endif /* CONFIG_EC_GOOGLE_CHROMEEC_I2C_PROTO3 */

#ifndef __PRE_RAM__
u8 google_chromeec_get_event(void)
{
	printk(BIOS_ERR, "%s: Not supported.\n", __func__);
	return 0;
}
#endif