1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Chromium OS cros_ec driver - SPI 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 <cros_ec.h>
17 #include <dm.h>
18 #include <errno.h>
19 #include <spi.h>
20
cros_ec_spi_packet(struct udevice * udev,int out_bytes,int in_bytes)21 int cros_ec_spi_packet(struct udevice *udev, int out_bytes, int in_bytes)
22 {
23 struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
24 struct spi_slave *slave = dev_get_parent_priv(dev->dev);
25 ulong start;
26 uint8_t byte;
27 int rv;
28
29 /* Do the transfer */
30 if (spi_claim_bus(slave)) {
31 debug("%s: Cannot claim SPI bus\n", __func__);
32 return -1;
33 }
34
35 rv = spi_xfer(slave, out_bytes * 8, dev->dout, NULL, SPI_XFER_BEGIN);
36 if (rv)
37 goto done;
38 start = get_timer(0);
39 while (1) {
40 rv = spi_xfer(slave, 8, NULL, &byte, 0);
41 if (byte == SPI_PREAMBLE_END_BYTE)
42 break;
43 if (rv)
44 goto done;
45 if (get_timer(start) > 100) {
46 rv = -ETIMEDOUT;
47 goto done;
48 }
49 }
50
51 rv = spi_xfer(slave, in_bytes * 8, NULL, dev->din, 0);
52 done:
53 spi_xfer(slave, 0, NULL, NULL, SPI_XFER_END);
54 spi_release_bus(slave);
55
56 if (rv) {
57 debug("%s: Cannot complete SPI transfer\n", __func__);
58 return -1;
59 }
60
61 return in_bytes;
62 }
63
64 /**
65 * Send a command to a LPC CROS_EC device and return the reply.
66 *
67 * The device's internal input/output buffers are used.
68 *
69 * @param dev CROS_EC device
70 * @param cmd Command to send (EC_CMD_...)
71 * @param cmd_version Version of command to send (EC_VER_...)
72 * @param dout Output data (may be NULL If dout_len=0)
73 * @param dout_len Size of output data in bytes
74 * @param dinp Returns pointer to response data. This will be
75 * untouched unless we return a value > 0.
76 * @param din_len Maximum size of response in bytes
77 * @return number of bytes in response, or -1 on error
78 */
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)79 int cros_ec_spi_command(struct udevice *udev, uint8_t cmd, int cmd_version,
80 const uint8_t *dout, int dout_len,
81 uint8_t **dinp, int din_len)
82 {
83 struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
84 struct spi_slave *slave = dev_get_parent_priv(dev->dev);
85 int in_bytes = din_len + 4; /* status, length, checksum, trailer */
86 uint8_t *out;
87 uint8_t *p;
88 int csum, len;
89 int rv;
90
91 if (dev->protocol_version != 2) {
92 debug("%s: Unsupported EC protcol version %d\n",
93 __func__, dev->protocol_version);
94 return -1;
95 }
96
97 /*
98 * Sanity-check input size to make sure it plus transaction overhead
99 * fits in the internal device buffer.
100 */
101 if (in_bytes > sizeof(dev->din)) {
102 debug("%s: Cannot receive %d bytes\n", __func__, din_len);
103 return -1;
104 }
105
106 /* We represent message length as a byte */
107 if (dout_len > 0xff) {
108 debug("%s: Cannot send %d bytes\n", __func__, dout_len);
109 return -1;
110 }
111
112 /*
113 * Clear input buffer so we don't get false hits for MSG_HEADER
114 */
115 memset(dev->din, '\0', in_bytes);
116
117 if (spi_claim_bus(slave)) {
118 debug("%s: Cannot claim SPI bus\n", __func__);
119 return -1;
120 }
121
122 out = dev->dout;
123 out[0] = EC_CMD_VERSION0 + cmd_version;
124 out[1] = cmd;
125 out[2] = (uint8_t)dout_len;
126 memcpy(out + 3, dout, dout_len);
127 csum = cros_ec_calc_checksum(out, 3)
128 + cros_ec_calc_checksum(dout, dout_len);
129 out[3 + dout_len] = (uint8_t)csum;
130
131 /*
132 * Send output data and receive input data starting such that the
133 * message body will be dword aligned.
134 */
135 p = dev->din + sizeof(int64_t) - 2;
136 len = dout_len + 4;
137 cros_ec_dump_data("out", cmd, out, len);
138 rv = spi_xfer(slave, max(len, in_bytes) * 8, out, p,
139 SPI_XFER_BEGIN | SPI_XFER_END);
140
141 spi_release_bus(slave);
142
143 if (rv) {
144 debug("%s: Cannot complete SPI transfer\n", __func__);
145 return -1;
146 }
147
148 len = min((int)p[1], din_len);
149 cros_ec_dump_data("in", -1, p, len + 3);
150
151 /* Response code is first byte of message */
152 if (p[0] != EC_RES_SUCCESS) {
153 printf("%s: Returned status %d\n", __func__, p[0]);
154 return -(int)(p[0]);
155 }
156
157 /* Check checksum */
158 csum = cros_ec_calc_checksum(p, len + 2);
159 if (csum != p[len + 2]) {
160 debug("%s: Invalid checksum rx %#02x, calced %#02x\n", __func__,
161 p[2 + len], csum);
162 return -1;
163 }
164
165 /* Anything else is the response data */
166 *dinp = p + 2;
167
168 return len;
169 }
170
cros_ec_probe(struct udevice * dev)171 static int cros_ec_probe(struct udevice *dev)
172 {
173 return cros_ec_register(dev);
174 }
175
176 static struct dm_cros_ec_ops cros_ec_ops = {
177 .packet = cros_ec_spi_packet,
178 .command = cros_ec_spi_command,
179 };
180
181 static const struct udevice_id cros_ec_ids[] = {
182 { .compatible = "google,cros-ec-spi" },
183 { }
184 };
185
186 U_BOOT_DRIVER(cros_ec_spi) = {
187 .name = "cros_ec_spi",
188 .id = UCLASS_CROS_EC,
189 .of_match = cros_ec_ids,
190 .probe = cros_ec_probe,
191 .ops = &cros_ec_ops,
192 };
193