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