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