summaryrefslogtreecommitdiff
path: root/drivers/misc/cros_ec_spi.c
blob: 153f971bdebe689f83154cbeea06ed62a335790e (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
// SPDX-License-Identifier: GPL-2.0+
/*
 * Chromium OS cros_ec driver - SPI interface
 *
 * Copyright (c) 2012 The Chromium OS Authors.
 */

/*
 * 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 <cros_ec.h>
#include <dm.h>
#include <errno.h>
#include <log.h>
#include <spi.h>

int cros_ec_spi_packet(struct udevice *udev, int out_bytes, int in_bytes)
{
	struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
	struct spi_slave *slave = dev_get_parent_priv(dev->dev);
	ulong start;
	uint8_t byte;
	int rv;

	/* Do the transfer */
	if (spi_claim_bus(slave)) {
		debug("%s: Cannot claim SPI bus\n", __func__);
		return -1;
	}

	rv = spi_xfer(slave, out_bytes * 8, dev->dout, NULL, SPI_XFER_BEGIN);
	if (rv)
		goto done;
	start = get_timer(0);
	while (1) {
		rv = spi_xfer(slave, 8, NULL, &byte, 0);
		if (byte == SPI_PREAMBLE_END_BYTE)
			break;
		if (rv)
			goto done;
		if (get_timer(start) > 100) {
			rv = -ETIMEDOUT;
			goto done;
		}
	}

	rv = spi_xfer(slave, in_bytes * 8, NULL, dev->din, 0);
done:
	spi_xfer(slave, 0, NULL, NULL, SPI_XFER_END);
	spi_release_bus(slave);

	if (rv) {
		debug("%s: Cannot complete SPI transfer\n", __func__);
		return -1;
	}

	return in_bytes;
}

/**
 * Send a command to a LPC CROS_EC device and return the reply.
 *
 * The device's internal input/output buffers are used.
 *
 * @param dev		CROS_EC device
 * @param cmd		Command to send (EC_CMD_...)
 * @param cmd_version	Version of command to send (EC_VER_...)
 * @param dout		Output data (may be NULL If dout_len=0)
 * @param dout_len      Size of output data in bytes
 * @param dinp		Returns pointer to response data. This will be
 *			untouched unless we return a value > 0.
 * @param din_len	Maximum size of response in bytes
 * @return number of bytes in response, or -1 on error
 */
int cros_ec_spi_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);
	struct spi_slave *slave = dev_get_parent_priv(dev->dev);
	int in_bytes = din_len + 4;	/* status, length, checksum, trailer */
	uint8_t *out;
	uint8_t *p;
	int csum, len;
	int rv;

	if (dev->protocol_version != 2) {
		debug("%s: Unsupported EC protcol version %d\n",
		      __func__, dev->protocol_version);
		return -1;
	}

	/*
	 * Sanity-check input size to make sure it plus transaction overhead
	 * fits in the internal device buffer.
	 */
	if (in_bytes > sizeof(dev->din)) {
		debug("%s: Cannot receive %d bytes\n", __func__, din_len);
		return -1;
	}

	/* We represent message length as a byte */
	if (dout_len > 0xff) {
		debug("%s: Cannot send %d bytes\n", __func__, dout_len);
		return -1;
	}

	/*
	 * Clear input buffer so we don't get false hits for MSG_HEADER
	 */
	memset(dev->din, '\0', in_bytes);

	if (spi_claim_bus(slave)) {
		debug("%s: Cannot claim SPI bus\n", __func__);
		return -1;
	}

	out = dev->dout;
	out[0] = EC_CMD_VERSION0 + cmd_version;
	out[1] = cmd;
	out[2] = (uint8_t)dout_len;
	memcpy(out + 3, dout, dout_len);
	csum = cros_ec_calc_checksum(out, 3)
	       + cros_ec_calc_checksum(dout, dout_len);
	out[3 + dout_len] = (uint8_t)csum;

	/*
	 * Send output data and receive input data starting such that the
	 * message body will be dword aligned.
	 */
	p = dev->din + sizeof(int64_t) - 2;
	len = dout_len + 4;
	cros_ec_dump_data("out", cmd, out, len);
	rv = spi_xfer(slave, max(len, in_bytes) * 8, out, p,
		      SPI_XFER_BEGIN | SPI_XFER_END);

	spi_release_bus(slave);

	if (rv) {
		debug("%s: Cannot complete SPI transfer\n", __func__);
		return -1;
	}

	len = min((int)p[1], din_len);
	cros_ec_dump_data("in", -1, p, len + 3);

	/* Response code is first byte of message */
	if (p[0] != EC_RES_SUCCESS) {
		printf("%s: Returned status %d\n", __func__, p[0]);
		return -(int)(p[0]);
	}

	/* Check checksum */
	csum = cros_ec_calc_checksum(p, len + 2);
	if (csum != p[len + 2]) {
		debug("%s: Invalid checksum rx %#02x, calced %#02x\n", __func__,
		      p[2 + len], csum);
		return -1;
	}

	/* Anything else is the response data */
	*dinp = p + 2;

	return len;
}

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

static struct dm_cros_ec_ops cros_ec_ops = {
	.packet = cros_ec_spi_packet,
	.command = cros_ec_spi_command,
};

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

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