1 /* 2 * Chromium OS cros_ec driver - SPI interface 3 * 4 * Copyright (c) 2012 The Chromium OS Authors. 5 * 6 * SPDX-License-Identifier: GPL-2.0+ 7 */ 8 9 /* 10 * The Matrix Keyboard Protocol driver handles talking to the keyboard 11 * controller chip. Mostly this is for keyboard functions, but some other 12 * things have slipped in, so we provide generic services to talk to the 13 * KBC. 14 */ 15 16 #include <common.h> 17 #include <cros_ec.h> 18 #include <dm.h> 19 #include <errno.h> 20 #include <spi.h> 21 22 DECLARE_GLOBAL_DATA_PTR; 23 24 int cros_ec_spi_packet(struct udevice *udev, int out_bytes, int in_bytes) 25 { 26 struct cros_ec_dev *dev = dev_get_uclass_priv(udev); 27 struct spi_slave *slave = dev_get_parent_priv(dev->dev); 28 ulong start; 29 uint8_t byte; 30 int rv; 31 32 /* Do the transfer */ 33 if (spi_claim_bus(slave)) { 34 debug("%s: Cannot claim SPI bus\n", __func__); 35 return -1; 36 } 37 38 rv = spi_xfer(slave, out_bytes * 8, dev->dout, NULL, SPI_XFER_BEGIN); 39 if (rv) 40 goto done; 41 start = get_timer(0); 42 while (1) { 43 rv = spi_xfer(slave, 8, NULL, &byte, 0); 44 if (byte == SPI_PREAMBLE_END_BYTE) 45 break; 46 if (rv) 47 goto done; 48 if (get_timer(start) > 100) { 49 rv = -ETIMEDOUT; 50 goto done; 51 } 52 } 53 54 rv = spi_xfer(slave, in_bytes * 8, NULL, dev->din, 0); 55 done: 56 spi_xfer(slave, 0, NULL, NULL, SPI_XFER_END); 57 spi_release_bus(slave); 58 59 if (rv) { 60 debug("%s: Cannot complete SPI transfer\n", __func__); 61 return -1; 62 } 63 64 return in_bytes; 65 } 66 67 /** 68 * Send a command to a LPC CROS_EC device and return the reply. 69 * 70 * The device's internal input/output buffers are used. 71 * 72 * @param dev CROS_EC device 73 * @param cmd Command to send (EC_CMD_...) 74 * @param cmd_version Version of command to send (EC_VER_...) 75 * @param dout Output data (may be NULL If dout_len=0) 76 * @param dout_len Size of output data in bytes 77 * @param dinp Returns pointer to response data. This will be 78 * untouched unless we return a value > 0. 79 * @param din_len Maximum size of response in bytes 80 * @return number of bytes in response, or -1 on error 81 */ 82 int cros_ec_spi_command(struct udevice *udev, uint8_t cmd, int cmd_version, 83 const uint8_t *dout, int dout_len, 84 uint8_t **dinp, int din_len) 85 { 86 struct cros_ec_dev *dev = dev_get_uclass_priv(udev); 87 struct spi_slave *slave = dev_get_parent_priv(dev->dev); 88 int in_bytes = din_len + 4; /* status, length, checksum, trailer */ 89 uint8_t *out; 90 uint8_t *p; 91 int csum, len; 92 int rv; 93 94 if (dev->protocol_version != 2) { 95 debug("%s: Unsupported EC protcol version %d\n", 96 __func__, dev->protocol_version); 97 return -1; 98 } 99 100 /* 101 * Sanity-check input size to make sure it plus transaction overhead 102 * fits in the internal device buffer. 103 */ 104 if (in_bytes > sizeof(dev->din)) { 105 debug("%s: Cannot receive %d bytes\n", __func__, din_len); 106 return -1; 107 } 108 109 /* We represent message length as a byte */ 110 if (dout_len > 0xff) { 111 debug("%s: Cannot send %d bytes\n", __func__, dout_len); 112 return -1; 113 } 114 115 /* 116 * Clear input buffer so we don't get false hits for MSG_HEADER 117 */ 118 memset(dev->din, '\0', in_bytes); 119 120 if (spi_claim_bus(slave)) { 121 debug("%s: Cannot claim SPI bus\n", __func__); 122 return -1; 123 } 124 125 out = dev->dout; 126 out[0] = EC_CMD_VERSION0 + cmd_version; 127 out[1] = cmd; 128 out[2] = (uint8_t)dout_len; 129 memcpy(out + 3, dout, dout_len); 130 csum = cros_ec_calc_checksum(out, 3) 131 + cros_ec_calc_checksum(dout, dout_len); 132 out[3 + dout_len] = (uint8_t)csum; 133 134 /* 135 * Send output data and receive input data starting such that the 136 * message body will be dword aligned. 137 */ 138 p = dev->din + sizeof(int64_t) - 2; 139 len = dout_len + 4; 140 cros_ec_dump_data("out", cmd, out, len); 141 rv = spi_xfer(slave, max(len, in_bytes) * 8, out, p, 142 SPI_XFER_BEGIN | SPI_XFER_END); 143 144 spi_release_bus(slave); 145 146 if (rv) { 147 debug("%s: Cannot complete SPI transfer\n", __func__); 148 return -1; 149 } 150 151 len = min((int)p[1], din_len); 152 cros_ec_dump_data("in", -1, p, len + 3); 153 154 /* Response code is first byte of message */ 155 if (p[0] != EC_RES_SUCCESS) { 156 printf("%s: Returned status %d\n", __func__, p[0]); 157 return -(int)(p[0]); 158 } 159 160 /* Check checksum */ 161 csum = cros_ec_calc_checksum(p, len + 2); 162 if (csum != p[len + 2]) { 163 debug("%s: Invalid checksum rx %#02x, calced %#02x\n", __func__, 164 p[2 + len], csum); 165 return -1; 166 } 167 168 /* Anything else is the response data */ 169 *dinp = p + 2; 170 171 return len; 172 } 173 174 static int cros_ec_probe(struct udevice *dev) 175 { 176 return cros_ec_register(dev); 177 } 178 179 static struct dm_cros_ec_ops cros_ec_ops = { 180 .packet = cros_ec_spi_packet, 181 .command = cros_ec_spi_command, 182 }; 183 184 static const struct udevice_id cros_ec_ids[] = { 185 { .compatible = "google,cros-ec-spi" }, 186 { } 187 }; 188 189 U_BOOT_DRIVER(cros_ec_spi) = { 190 .name = "cros_ec_spi", 191 .id = UCLASS_CROS_EC, 192 .of_match = cros_ec_ids, 193 .probe = cros_ec_probe, 194 .ops = &cros_ec_ops, 195 }; 196