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_command(struct udevice *udev, uint8_t cmd, int cmd_version, 44 const uint8_t *dout, int dout_len, 45 uint8_t **dinp, int din_len) 46 { 47 struct cros_ec_dev *dev = dev_get_uclass_priv(udev); 48 const int cmd_addr = EC_LPC_ADDR_HOST_CMD; 49 const int data_addr = EC_LPC_ADDR_HOST_DATA; 50 const int args_addr = EC_LPC_ADDR_HOST_ARGS; 51 const int param_addr = EC_LPC_ADDR_HOST_PARAM; 52 53 struct ec_lpc_host_args args; 54 uint8_t *d; 55 int csum; 56 int i; 57 58 if (dout_len > EC_PROTO2_MAX_PARAM_SIZE) { 59 debug("%s: Cannot send %d bytes\n", __func__, dout_len); 60 return -1; 61 } 62 63 /* Fill in args */ 64 args.flags = EC_HOST_ARGS_FLAG_FROM_HOST; 65 args.command_version = cmd_version; 66 args.data_size = dout_len; 67 68 /* Calculate checksum */ 69 csum = cmd + args.flags + args.command_version + args.data_size; 70 for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++) 71 csum += *d; 72 73 args.checksum = (uint8_t)csum; 74 75 if (wait_for_sync(dev)) { 76 debug("%s: Timeout waiting ready\n", __func__); 77 return -1; 78 } 79 80 /* Write args */ 81 for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++) 82 outb(*d, args_addr + i); 83 84 /* Write data, if any */ 85 debug_trace("cmd: %02x, ver: %02x", cmd, cmd_version); 86 for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++) { 87 outb(*d, param_addr + i); 88 debug_trace("%02x ", *d); 89 } 90 91 outb(cmd, cmd_addr); 92 debug_trace("\n"); 93 94 if (wait_for_sync(dev)) { 95 debug("%s: Timeout waiting for response\n", __func__); 96 return -1; 97 } 98 99 /* Check result */ 100 i = inb(data_addr); 101 if (i) { 102 debug("%s: CROS_EC result code %d\n", __func__, i); 103 return -i; 104 } 105 106 /* Read back args */ 107 for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++) 108 *d = inb(args_addr + i); 109 110 /* 111 * If EC didn't modify args flags, then somehow we sent a new-style 112 * command to an old EC, which means it would have read its params 113 * from the wrong place. 114 */ 115 if (!(args.flags & EC_HOST_ARGS_FLAG_TO_HOST)) { 116 debug("%s: CROS_EC protocol mismatch\n", __func__); 117 return -EC_RES_INVALID_RESPONSE; 118 } 119 120 if (args.data_size > din_len) { 121 debug("%s: CROS_EC returned too much data %d > %d\n", 122 __func__, args.data_size, din_len); 123 return -EC_RES_INVALID_RESPONSE; 124 } 125 126 /* Read data, if any */ 127 for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++) { 128 *d = inb(param_addr + i); 129 debug_trace("%02x ", *d); 130 } 131 debug_trace("\n"); 132 133 /* Verify checksum */ 134 csum = cmd + args.flags + args.command_version + args.data_size; 135 for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++) 136 csum += *d; 137 138 if (args.checksum != (uint8_t)csum) { 139 debug("%s: CROS_EC response has invalid checksum\n", __func__); 140 return -EC_RES_INVALID_CHECKSUM; 141 } 142 *dinp = dev->din; 143 144 /* Return actual amount of data received */ 145 return args.data_size; 146 } 147 148 /** 149 * Initialize LPC protocol. 150 * 151 * @param dev CROS_EC device 152 * @param blob Device tree blob 153 * @return 0 if ok, -1 on error 154 */ 155 int cros_ec_lpc_init(struct cros_ec_dev *dev, const void *blob) 156 { 157 int byte, i; 158 159 /* See if we can find an EC at the other end */ 160 byte = 0xff; 161 byte &= inb(EC_LPC_ADDR_HOST_CMD); 162 byte &= inb(EC_LPC_ADDR_HOST_DATA); 163 for (i = 0; i < EC_PROTO2_MAX_PARAM_SIZE && (byte == 0xff); i++) 164 byte &= inb(EC_LPC_ADDR_HOST_PARAM + i); 165 if (byte == 0xff) { 166 debug("%s: CROS_EC device not found on LPC bus\n", 167 __func__); 168 return -1; 169 } 170 171 return 0; 172 } 173 174 /* 175 * Test if LPC command args are supported. 176 * 177 * The cheapest way to do this is by looking for the memory-mapped 178 * flag. This is faster than sending a new-style 'hello' command and 179 * seeing whether the EC sets the EC_HOST_ARGS_FLAG_FROM_HOST flag 180 * in args when it responds. 181 */ 182 static int cros_ec_lpc_check_version(struct udevice *dev) 183 { 184 if (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) == 'E' && 185 inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) 186 == 'C' && 187 (inb(EC_LPC_ADDR_MEMMAP + 188 EC_MEMMAP_HOST_CMD_FLAGS) & 189 EC_HOST_CMD_FLAG_LPC_ARGS_SUPPORTED)) { 190 return 0; 191 } 192 193 printf("%s: ERROR: old EC interface not supported\n", __func__); 194 return -1; 195 } 196 197 static int cros_ec_probe(struct udevice *dev) 198 { 199 return cros_ec_register(dev); 200 } 201 202 static struct dm_cros_ec_ops cros_ec_ops = { 203 .command = cros_ec_lpc_command, 204 .check_version = cros_ec_lpc_check_version, 205 }; 206 207 static const struct udevice_id cros_ec_ids[] = { 208 { .compatible = "google,cros-ec-lpc" }, 209 { } 210 }; 211 212 U_BOOT_DRIVER(cros_ec_lpc) = { 213 .name = "cros_ec_lpc", 214 .id = UCLASS_CROS_EC, 215 .of_match = cros_ec_ids, 216 .probe = cros_ec_probe, 217 .ops = &cros_ec_ops, 218 }; 219