1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Chromium OS cros_ec driver - LPC 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 <dm.h> 17 #include <command.h> 18 #include <cros_ec.h> 19 #include <asm/io.h> 20 21 #ifdef DEBUG_TRACE 22 #define debug_trace(fmt, b...) debug(fmt, ##b) 23 #else 24 #define debug_trace(fmt, b...) 25 #endif 26 27 static int wait_for_sync(struct cros_ec_dev *dev) 28 { 29 unsigned long start; 30 31 start = get_timer(0); 32 while (inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK) { 33 if (get_timer(start) > 1000) { 34 debug("%s: Timeout waiting for CROS_EC sync\n", 35 __func__); 36 return -1; 37 } 38 } 39 40 return 0; 41 } 42 43 int cros_ec_lpc_packet(struct udevice *udev, int out_bytes, int in_bytes) 44 { 45 struct cros_ec_dev *dev = dev_get_uclass_priv(udev); 46 uint8_t *d; 47 int i; 48 49 if (out_bytes > EC_LPC_HOST_PACKET_SIZE) 50 return log_msg_ret("Cannot send that many bytes\n", -E2BIG); 51 52 if (in_bytes > EC_LPC_HOST_PACKET_SIZE) 53 return log_msg_ret("Cannot receive that many bytes\n", -E2BIG); 54 55 if (wait_for_sync(dev)) 56 return log_msg_ret("Timeout waiting ready\n", -ETIMEDOUT); 57 58 /* Write data */ 59 for (i = 0, d = (uint8_t *)dev->dout; i < out_bytes; i++, d++) 60 outb(*d, EC_LPC_ADDR_HOST_PACKET + i); 61 62 /* Start the command */ 63 outb(EC_COMMAND_PROTOCOL_3, EC_LPC_ADDR_HOST_CMD); 64 65 if (wait_for_sync(dev)) 66 return log_msg_ret("Timeout waiting ready\n", -ETIMEDOUT); 67 68 /* Read back args */ 69 for (i = 0, d = dev->din; i < in_bytes; i++, d++) 70 *d = inb(EC_LPC_ADDR_HOST_PACKET + i); 71 72 return in_bytes; 73 } 74 75 int cros_ec_lpc_command(struct udevice *udev, uint8_t cmd, int cmd_version, 76 const uint8_t *dout, int dout_len, 77 uint8_t **dinp, int din_len) 78 { 79 struct cros_ec_dev *dev = dev_get_uclass_priv(udev); 80 const int cmd_addr = EC_LPC_ADDR_HOST_CMD; 81 const int data_addr = EC_LPC_ADDR_HOST_DATA; 82 const int args_addr = EC_LPC_ADDR_HOST_ARGS; 83 const int param_addr = EC_LPC_ADDR_HOST_PARAM; 84 85 struct ec_lpc_host_args args; 86 uint8_t *d; 87 int csum; 88 int i; 89 90 if (dout_len > EC_PROTO2_MAX_PARAM_SIZE) { 91 debug("%s: Cannot send %d bytes\n", __func__, dout_len); 92 return -1; 93 } 94 95 /* Fill in args */ 96 args.flags = EC_HOST_ARGS_FLAG_FROM_HOST; 97 args.command_version = cmd_version; 98 args.data_size = dout_len; 99 100 /* Calculate checksum */ 101 csum = cmd + args.flags + args.command_version + args.data_size; 102 for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++) 103 csum += *d; 104 105 args.checksum = (uint8_t)csum; 106 107 if (wait_for_sync(dev)) { 108 debug("%s: Timeout waiting ready\n", __func__); 109 return -1; 110 } 111 112 /* Write args */ 113 for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++) 114 outb(*d, args_addr + i); 115 116 /* Write data, if any */ 117 debug_trace("cmd: %02x, ver: %02x", cmd, cmd_version); 118 for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++) { 119 outb(*d, param_addr + i); 120 debug_trace("%02x ", *d); 121 } 122 123 outb(cmd, cmd_addr); 124 debug_trace("\n"); 125 126 if (wait_for_sync(dev)) { 127 debug("%s: Timeout waiting for response\n", __func__); 128 return -1; 129 } 130 131 /* Check result */ 132 i = inb(data_addr); 133 if (i) { 134 debug("%s: CROS_EC result code %d\n", __func__, i); 135 return -i; 136 } 137 138 /* Read back args */ 139 for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++) 140 *d = inb(args_addr + i); 141 142 /* 143 * If EC didn't modify args flags, then somehow we sent a new-style 144 * command to an old EC, which means it would have read its params 145 * from the wrong place. 146 */ 147 if (!(args.flags & EC_HOST_ARGS_FLAG_TO_HOST)) { 148 debug("%s: CROS_EC protocol mismatch\n", __func__); 149 return -EC_RES_INVALID_RESPONSE; 150 } 151 152 if (args.data_size > din_len) { 153 debug("%s: CROS_EC returned too much data %d > %d\n", 154 __func__, args.data_size, din_len); 155 return -EC_RES_INVALID_RESPONSE; 156 } 157 158 /* Read data, if any */ 159 for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++) { 160 *d = inb(param_addr + i); 161 debug_trace("%02x ", *d); 162 } 163 debug_trace("\n"); 164 165 /* Verify checksum */ 166 csum = cmd + args.flags + args.command_version + args.data_size; 167 for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++) 168 csum += *d; 169 170 if (args.checksum != (uint8_t)csum) { 171 debug("%s: CROS_EC response has invalid checksum\n", __func__); 172 return -EC_RES_INVALID_CHECKSUM; 173 } 174 *dinp = dev->din; 175 176 /* Return actual amount of data received */ 177 return args.data_size; 178 } 179 180 /** 181 * Initialize LPC 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_lpc_init(struct cros_ec_dev *dev, const void *blob) 188 { 189 int byte, i; 190 191 /* See if we can find an EC at the other end */ 192 byte = 0xff; 193 byte &= inb(EC_LPC_ADDR_HOST_CMD); 194 byte &= inb(EC_LPC_ADDR_HOST_DATA); 195 for (i = 0; i < EC_PROTO2_MAX_PARAM_SIZE && (byte == 0xff); i++) 196 byte &= inb(EC_LPC_ADDR_HOST_PARAM + i); 197 if (byte == 0xff) { 198 debug("%s: CROS_EC device not found on LPC bus\n", 199 __func__); 200 return -1; 201 } 202 203 return 0; 204 } 205 206 /* 207 * Test if LPC command args are supported. 208 * 209 * The cheapest way to do this is by looking for the memory-mapped 210 * flag. This is faster than sending a new-style 'hello' command and 211 * seeing whether the EC sets the EC_HOST_ARGS_FLAG_FROM_HOST flag 212 * in args when it responds. 213 */ 214 static int cros_ec_lpc_check_version(struct udevice *dev) 215 { 216 if (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) == 'E' && 217 inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) 218 == 'C' && 219 (inb(EC_LPC_ADDR_MEMMAP + 220 EC_MEMMAP_HOST_CMD_FLAGS) & 221 EC_HOST_CMD_FLAG_LPC_ARGS_SUPPORTED)) { 222 return 0; 223 } 224 225 printf("%s: ERROR: old EC interface not supported\n", __func__); 226 return -1; 227 } 228 229 static int cros_ec_probe(struct udevice *dev) 230 { 231 return cros_ec_register(dev); 232 } 233 234 static struct dm_cros_ec_ops cros_ec_ops = { 235 .packet = cros_ec_lpc_packet, 236 .command = cros_ec_lpc_command, 237 .check_version = cros_ec_lpc_check_version, 238 }; 239 240 static const struct udevice_id cros_ec_ids[] = { 241 { .compatible = "google,cros-ec-lpc" }, 242 { } 243 }; 244 245 U_BOOT_DRIVER(cros_ec_lpc) = { 246 .name = "cros_ec_lpc", 247 .id = UCLASS_CROS_EC, 248 .of_match = cros_ec_ids, 249 .probe = cros_ec_probe, 250 .ops = &cros_ec_ops, 251 }; 252