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 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 */ 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 } 170 171 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