1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Chromium OS cros_ec driver - I2C interface
4 *
5 * Copyright (c) 2012 The Chromium OS Authors.
6 */
7
8 /*
9 * The Matrix Keyboard Protocol driver handles talking to the keyboard
10 * controller chip. Mostly this is for keyboard functions, but some other
11 * things have slipped in, so we provide generic services to talk to the
12 * KBC.
13 */
14
15 #include <common.h>
16 #include <dm.h>
17 #include <i2c.h>
18 #include <cros_ec.h>
19 #include <log.h>
20
21 #ifdef DEBUG_TRACE
22 #define debug_trace(fmt, b...) debug(fmt, #b)
23 #else
24 #define debug_trace(fmt, b...)
25 #endif
26
27 /**
28 * Request format for protocol v3
29 * byte 0 0xda (EC_COMMAND_PROTOCOL_3)
30 * byte 1-8 struct ec_host_request
31 * byte 10- response data
32 */
33 struct ec_host_request_i2c {
34 /* Always 0xda to backward compatible with v2 struct */
35 uint8_t command_protocol;
36 struct ec_host_request ec_request;
37 } __packed;
38
39 /*
40 * Response format for protocol v3
41 * byte 0 result code
42 * byte 1 packet_length
43 * byte 2-9 struct ec_host_response
44 * byte 10- response data
45 */
46 struct ec_host_response_i2c {
47 uint8_t result;
48 uint8_t packet_length;
49 struct ec_host_response ec_response;
50 } __packed;
51
cros_ec_i2c_packet(struct udevice * udev,int out_bytes,int in_bytes)52 static int cros_ec_i2c_packet(struct udevice *udev, int out_bytes, int in_bytes)
53 {
54 struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
55 struct dm_i2c_chip *chip = dev_get_parent_platdata(udev);
56 struct ec_host_request_i2c *ec_request_i2c =
57 (struct ec_host_request_i2c *)dev->dout;
58 struct ec_host_response_i2c *ec_response_i2c =
59 (struct ec_host_response_i2c *)dev->din;
60 struct i2c_msg i2c_msg[2];
61 int ret;
62
63 i2c_msg[0].addr = chip->chip_addr;
64 i2c_msg[0].flags = 0;
65 i2c_msg[1].addr = chip->chip_addr;
66 i2c_msg[1].flags = I2C_M_RD;
67
68 /* one extra byte, to indicate v3 */
69 i2c_msg[0].len = out_bytes + 1;
70 i2c_msg[0].buf = dev->dout;
71
72 /* stitch on EC_COMMAND_PROTOCOL_3 */
73 memmove(&ec_request_i2c->ec_request, dev->dout, out_bytes);
74 ec_request_i2c->command_protocol = EC_COMMAND_PROTOCOL_3;
75
76 /* two extra bytes for v3 */
77 i2c_msg[1].len = in_bytes + 2;
78 i2c_msg[1].buf = dev->din;
79
80 ret = dm_i2c_xfer(udev, &i2c_msg[0], 2);
81 if (ret) {
82 printf("%s: Could not execute transfer: %d\n", __func__, ret);
83 return ret;
84 }
85
86 /* When we send a v3 request to v2 ec, ec won't recognize the 0xda
87 * (EC_COMMAND_PROTOCOL_3) and will return with status
88 * EC_RES_INVALID_COMMAND with zero data length
89 *
90 * In case of invalid command for v3 protocol the data length
91 * will be at least sizeof(struct ec_host_response)
92 */
93 if (ec_response_i2c->result == EC_RES_INVALID_COMMAND &&
94 ec_response_i2c->packet_length == 0)
95 return -EPROTONOSUPPORT;
96
97 if (ec_response_i2c->packet_length < sizeof(struct ec_host_response)) {
98 printf("%s: response of %u bytes too short; not a full hdr\n",
99 __func__, ec_response_i2c->packet_length);
100 return -EBADMSG;
101 }
102
103
104 /* drop result and packet_len */
105 memmove(dev->din, &ec_response_i2c->ec_response, in_bytes);
106
107 return in_bytes;
108 }
109
cros_ec_i2c_command(struct udevice * udev,uint8_t cmd,int cmd_version,const uint8_t * dout,int dout_len,uint8_t ** dinp,int din_len)110 static int cros_ec_i2c_command(struct udevice *udev, uint8_t cmd,
111 int cmd_version, const uint8_t *dout,
112 int dout_len, uint8_t **dinp, int din_len)
113 {
114 struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
115 struct dm_i2c_chip *chip = dev_get_parent_platdata(udev);
116 struct i2c_msg i2c_msg[2];
117 /* version8, cmd8, arglen8, out8[dout_len], csum8 */
118 int out_bytes = dout_len + 4;
119 /* response8, arglen8, in8[din_len], checksum8 */
120 int in_bytes = din_len + 3;
121 uint8_t *ptr;
122 /* Receive input data, so that args will be dword aligned */
123 uint8_t *in_ptr;
124 int len, csum, ret;
125
126 /*
127 * Sanity-check I/O sizes given transaction overhead in internal
128 * buffers.
129 */
130 if (out_bytes > sizeof(dev->dout)) {
131 debug("%s: Cannot send %d bytes\n", __func__, dout_len);
132 return -1;
133 }
134 if (in_bytes > sizeof(dev->din)) {
135 debug("%s: Cannot receive %d bytes\n", __func__, din_len);
136 return -1;
137 }
138 assert(dout_len >= 0);
139 assert(dinp);
140
141 i2c_msg[0].addr = chip->chip_addr;
142 i2c_msg[0].len = out_bytes;
143 i2c_msg[0].buf = dev->dout;
144 i2c_msg[0].flags = 0;
145
146 /*
147 * Copy command and data into output buffer so we can do a single I2C
148 * burst transaction.
149 */
150 ptr = dev->dout;
151
152 /*
153 * in_ptr starts of pointing to a dword-aligned input data buffer.
154 * We decrement it back by the number of header bytes we expect to
155 * receive, so that the first parameter of the resulting input data
156 * will be dword aligned.
157 */
158 in_ptr = dev->din + sizeof(int64_t);
159
160 if (dev->protocol_version != 2) {
161 /* Something we don't support */
162 debug("%s: Protocol version %d unsupported\n",
163 __func__, dev->protocol_version);
164 return -1;
165 }
166
167 *ptr++ = EC_CMD_VERSION0 + cmd_version;
168 *ptr++ = cmd;
169 *ptr++ = dout_len;
170 in_ptr -= 2; /* Expect status, length bytes */
171
172 memcpy(ptr, dout, dout_len);
173 ptr += dout_len;
174
175 *ptr++ = (uint8_t)
176 cros_ec_calc_checksum(dev->dout, dout_len + 3);
177
178 i2c_msg[1].addr = chip->chip_addr;
179 i2c_msg[1].len = in_bytes;
180 i2c_msg[1].buf = in_ptr;
181 i2c_msg[1].flags = I2C_M_RD;
182
183 /* Send output data */
184 cros_ec_dump_data("out", -1, dev->dout, out_bytes);
185
186 ret = dm_i2c_xfer(udev, &i2c_msg[0], 2);
187 if (ret) {
188 debug("%s: Could not execute transfer to %s\n", __func__,
189 udev->name);
190 ret = -1;
191 }
192
193 if (*in_ptr != EC_RES_SUCCESS) {
194 debug("%s: Received bad result code %d\n", __func__, *in_ptr);
195 return -(int)*in_ptr;
196 }
197
198 len = in_ptr[1];
199 if (len + 3 > sizeof(dev->din)) {
200 debug("%s: Received length %#02x too large\n",
201 __func__, len);
202 return -1;
203 }
204 csum = cros_ec_calc_checksum(in_ptr, 2 + len);
205 if (csum != in_ptr[2 + len]) {
206 debug("%s: Invalid checksum rx %#02x, calced %#02x\n",
207 __func__, in_ptr[2 + din_len], csum);
208 return -1;
209 }
210 din_len = min(din_len, len);
211 cros_ec_dump_data("in", -1, in_ptr, din_len + 3);
212
213 /* Return pointer to dword-aligned input data, if any */
214 *dinp = dev->din + sizeof(int64_t);
215
216 return din_len;
217 }
218
cros_ec_probe(struct udevice * dev)219 static int cros_ec_probe(struct udevice *dev)
220 {
221 return cros_ec_register(dev);
222 }
223
224 static struct dm_cros_ec_ops cros_ec_ops = {
225 .command = cros_ec_i2c_command,
226 .packet = cros_ec_i2c_packet,
227 };
228
229 static const struct udevice_id cros_ec_ids[] = {
230 { .compatible = "google,cros-ec-i2c" },
231 { }
232 };
233
234 U_BOOT_DRIVER(cros_ec_i2c) = {
235 .name = "cros_ec_i2c",
236 .id = UCLASS_CROS_EC,
237 .of_match = cros_ec_ids,
238 .probe = cros_ec_probe,
239 .ops = &cros_ec_ops,
240 };
241