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 #ifdef CONFIG_DM_CROS_EC 25 int cros_ec_spi_packet(struct udevice *udev, int out_bytes, int in_bytes) 26 { 27 struct cros_ec_dev *dev = udev->uclass_priv; 28 #else 29 int cros_ec_spi_packet(struct cros_ec_dev *dev, int out_bytes, int in_bytes) 30 { 31 #endif 32 struct spi_slave *slave = dev_get_parentdata(dev->dev); 33 int rv; 34 35 /* Do the transfer */ 36 if (spi_claim_bus(slave)) { 37 debug("%s: Cannot claim SPI bus\n", __func__); 38 return -1; 39 } 40 41 rv = spi_xfer(slave, max(out_bytes, in_bytes) * 8, 42 dev->dout, dev->din, 43 SPI_XFER_BEGIN | SPI_XFER_END); 44 45 spi_release_bus(slave); 46 47 if (rv) { 48 debug("%s: Cannot complete SPI transfer\n", __func__); 49 return -1; 50 } 51 52 return in_bytes; 53 } 54 55 /** 56 * Send a command to a LPC CROS_EC device and return the reply. 57 * 58 * The device's internal input/output buffers are used. 59 * 60 * @param dev CROS_EC device 61 * @param cmd Command to send (EC_CMD_...) 62 * @param cmd_version Version of command to send (EC_VER_...) 63 * @param dout Output data (may be NULL If dout_len=0) 64 * @param dout_len Size of output data in bytes 65 * @param dinp Returns pointer to response data. This will be 66 * untouched unless we return a value > 0. 67 * @param din_len Maximum size of response in bytes 68 * @return number of bytes in response, or -1 on error 69 */ 70 #ifdef CONFIG_DM_CROS_EC 71 int cros_ec_spi_command(struct udevice *udev, uint8_t cmd, int cmd_version, 72 const uint8_t *dout, int dout_len, 73 uint8_t **dinp, int din_len) 74 { 75 struct cros_ec_dev *dev = udev->uclass_priv; 76 #else 77 int cros_ec_spi_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version, 78 const uint8_t *dout, int dout_len, 79 uint8_t **dinp, int din_len) 80 { 81 #endif 82 struct spi_slave *slave = dev_get_parentdata(dev->dev); 83 int in_bytes = din_len + 4; /* status, length, checksum, trailer */ 84 uint8_t *out; 85 uint8_t *p; 86 int csum, len; 87 int rv; 88 89 if (dev->protocol_version != 2) { 90 debug("%s: Unsupported EC protcol version %d\n", 91 __func__, dev->protocol_version); 92 return -1; 93 } 94 95 /* 96 * Sanity-check input size to make sure it plus transaction overhead 97 * fits in the internal device buffer. 98 */ 99 if (in_bytes > sizeof(dev->din)) { 100 debug("%s: Cannot receive %d bytes\n", __func__, din_len); 101 return -1; 102 } 103 104 /* We represent message length as a byte */ 105 if (dout_len > 0xff) { 106 debug("%s: Cannot send %d bytes\n", __func__, dout_len); 107 return -1; 108 } 109 110 /* 111 * Clear input buffer so we don't get false hits for MSG_HEADER 112 */ 113 memset(dev->din, '\0', in_bytes); 114 115 if (spi_claim_bus(slave)) { 116 debug("%s: Cannot claim SPI bus\n", __func__); 117 return -1; 118 } 119 120 out = dev->dout; 121 out[0] = EC_CMD_VERSION0 + cmd_version; 122 out[1] = cmd; 123 out[2] = (uint8_t)dout_len; 124 memcpy(out + 3, dout, dout_len); 125 csum = cros_ec_calc_checksum(out, 3) 126 + cros_ec_calc_checksum(dout, dout_len); 127 out[3 + dout_len] = (uint8_t)csum; 128 129 /* 130 * Send output data and receive input data starting such that the 131 * message body will be dword aligned. 132 */ 133 p = dev->din + sizeof(int64_t) - 2; 134 len = dout_len + 4; 135 cros_ec_dump_data("out", cmd, out, len); 136 rv = spi_xfer(slave, max(len, in_bytes) * 8, out, p, 137 SPI_XFER_BEGIN | SPI_XFER_END); 138 139 spi_release_bus(slave); 140 141 if (rv) { 142 debug("%s: Cannot complete SPI transfer\n", __func__); 143 return -1; 144 } 145 146 len = min(p[1], din_len); 147 cros_ec_dump_data("in", -1, p, len + 3); 148 149 /* Response code is first byte of message */ 150 if (p[0] != EC_RES_SUCCESS) { 151 printf("%s: Returned status %d\n", __func__, p[0]); 152 return -(int)(p[0]); 153 } 154 155 /* Check checksum */ 156 csum = cros_ec_calc_checksum(p, len + 2); 157 if (csum != p[len + 2]) { 158 debug("%s: Invalid checksum rx %#02x, calced %#02x\n", __func__, 159 p[2 + len], csum); 160 return -1; 161 } 162 163 /* Anything else is the response data */ 164 *dinp = p + 2; 165 166 return len; 167 } 168 169 #ifndef CONFIG_DM_CROS_EC 170 int cros_ec_spi_decode_fdt(struct cros_ec_dev *dev, const void *blob) 171 { 172 /* Decode interface-specific FDT params */ 173 dev->max_frequency = fdtdec_get_int(blob, dev->node, 174 "spi-max-frequency", 500000); 175 dev->cs = fdtdec_get_int(blob, dev->node, "reg", 0); 176 177 return 0; 178 } 179 180 /** 181 * Initialize SPI protocol. 182 * 183 * @param dev CROS_EC device 184 * @param blob Device tree blob 185 * @return 0 if ok, -1 on error 186 */ 187 int cros_ec_spi_init(struct cros_ec_dev *dev, const void *blob) 188 { 189 int ret; 190 191 ret = spi_setup_slave_fdt(blob, dev->node, dev->parent_node, 192 &slave); 193 if (ret) { 194 debug("%s: Could not setup SPI slave\n", __func__); 195 return ret; 196 } 197 198 return 0; 199 } 200 #endif 201 202 #ifdef CONFIG_DM_CROS_EC 203 int cros_ec_probe(struct udevice *dev) 204 { 205 struct spi_slave *slave = dev_get_parentdata(dev); 206 int ret; 207 208 /* 209 * TODO(sjg@chromium.org) 210 * 211 * This is really horrible at present. It is an artifact of removing 212 * the child_pre_probe() method for SPI. Everything here could go in 213 * an automatic function, except that spi_get_bus_and_cs() wants to 214 * set it up manually and call device_probe_child(). 215 * 216 * The solution may be to re-enable the child_pre_probe() method for 217 * SPI and have it do nothing if the child is already passed in via 218 * device_probe_child(). 219 */ 220 slave->dev = dev; 221 ret = spi_ofdata_to_platdata(gd->fdt_blob, dev->of_offset, slave); 222 if (ret) 223 return ret; 224 return cros_ec_register(dev); 225 } 226 227 struct dm_cros_ec_ops cros_ec_ops = { 228 .packet = cros_ec_spi_packet, 229 .command = cros_ec_spi_command, 230 }; 231 232 static const struct udevice_id cros_ec_ids[] = { 233 { .compatible = "google,cros-ec" }, 234 { } 235 }; 236 237 U_BOOT_DRIVER(cros_ec_spi) = { 238 .name = "cros_ec", 239 .id = UCLASS_CROS_EC, 240 .of_match = cros_ec_ids, 241 .probe = cros_ec_probe, 242 .ops = &cros_ec_ops, 243 }; 244 #endif 245