1 /* 2 * Chromium OS cros_ec driver - LPC 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 <dm.h> 18 #include <command.h> 19 #include <cros_ec.h> 20 #include <asm/io.h> 21 22 #ifdef DEBUG_TRACE 23 #define debug_trace(fmt, b...) debug(fmt, ##b) 24 #else 25 #define debug_trace(fmt, b...) 26 #endif 27 28 static int wait_for_sync(struct cros_ec_dev *dev) 29 { 30 unsigned long start; 31 32 start = get_timer(0); 33 while (inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK) { 34 if (get_timer(start) > 1000) { 35 debug("%s: Timeout waiting for CROS_EC sync\n", 36 __func__); 37 return -1; 38 } 39 } 40 41 return 0; 42 } 43 44 #ifdef CONFIG_DM_CROS_EC 45 int cros_ec_lpc_command(struct udevice *udev, uint8_t cmd, int cmd_version, 46 const uint8_t *dout, int dout_len, 47 uint8_t **dinp, int din_len) 48 { 49 struct cros_ec_dev *dev = dev_get_uclass_priv(udev); 50 #else 51 int cros_ec_lpc_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version, 52 const uint8_t *dout, int dout_len, 53 uint8_t **dinp, int din_len) 54 { 55 #endif 56 const int cmd_addr = EC_LPC_ADDR_HOST_CMD; 57 const int data_addr = EC_LPC_ADDR_HOST_DATA; 58 const int args_addr = EC_LPC_ADDR_HOST_ARGS; 59 const int param_addr = EC_LPC_ADDR_HOST_PARAM; 60 61 struct ec_lpc_host_args args; 62 uint8_t *d; 63 int csum; 64 int i; 65 66 if (dout_len > EC_PROTO2_MAX_PARAM_SIZE) { 67 debug("%s: Cannot send %d bytes\n", __func__, dout_len); 68 return -1; 69 } 70 71 /* Fill in args */ 72 args.flags = EC_HOST_ARGS_FLAG_FROM_HOST; 73 args.command_version = cmd_version; 74 args.data_size = dout_len; 75 76 /* Calculate checksum */ 77 csum = cmd + args.flags + args.command_version + args.data_size; 78 for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++) 79 csum += *d; 80 81 args.checksum = (uint8_t)csum; 82 83 if (wait_for_sync(dev)) { 84 debug("%s: Timeout waiting ready\n", __func__); 85 return -1; 86 } 87 88 /* Write args */ 89 for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++) 90 outb(*d, args_addr + i); 91 92 /* Write data, if any */ 93 debug_trace("cmd: %02x, ver: %02x", cmd, cmd_version); 94 for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++) { 95 outb(*d, param_addr + i); 96 debug_trace("%02x ", *d); 97 } 98 99 outb(cmd, cmd_addr); 100 debug_trace("\n"); 101 102 if (wait_for_sync(dev)) { 103 debug("%s: Timeout waiting for response\n", __func__); 104 return -1; 105 } 106 107 /* Check result */ 108 i = inb(data_addr); 109 if (i) { 110 debug("%s: CROS_EC result code %d\n", __func__, i); 111 return -i; 112 } 113 114 /* Read back args */ 115 for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++) 116 *d = inb(args_addr + i); 117 118 /* 119 * If EC didn't modify args flags, then somehow we sent a new-style 120 * command to an old EC, which means it would have read its params 121 * from the wrong place. 122 */ 123 if (!(args.flags & EC_HOST_ARGS_FLAG_TO_HOST)) { 124 debug("%s: CROS_EC protocol mismatch\n", __func__); 125 return -EC_RES_INVALID_RESPONSE; 126 } 127 128 if (args.data_size > din_len) { 129 debug("%s: CROS_EC returned too much data %d > %d\n", 130 __func__, args.data_size, din_len); 131 return -EC_RES_INVALID_RESPONSE; 132 } 133 134 /* Read data, if any */ 135 for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++) { 136 *d = inb(param_addr + i); 137 debug_trace("%02x ", *d); 138 } 139 debug_trace("\n"); 140 141 /* Verify checksum */ 142 csum = cmd + args.flags + args.command_version + args.data_size; 143 for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++) 144 csum += *d; 145 146 if (args.checksum != (uint8_t)csum) { 147 debug("%s: CROS_EC response has invalid checksum\n", __func__); 148 return -EC_RES_INVALID_CHECKSUM; 149 } 150 *dinp = dev->din; 151 152 /* Return actual amount of data received */ 153 return args.data_size; 154 } 155 156 /** 157 * Initialize LPC protocol. 158 * 159 * @param dev CROS_EC device 160 * @param blob Device tree blob 161 * @return 0 if ok, -1 on error 162 */ 163 int cros_ec_lpc_init(struct cros_ec_dev *dev, const void *blob) 164 { 165 int byte, i; 166 167 /* See if we can find an EC at the other end */ 168 byte = 0xff; 169 byte &= inb(EC_LPC_ADDR_HOST_CMD); 170 byte &= inb(EC_LPC_ADDR_HOST_DATA); 171 for (i = 0; i < EC_PROTO2_MAX_PARAM_SIZE && (byte == 0xff); i++) 172 byte &= inb(EC_LPC_ADDR_HOST_PARAM + i); 173 if (byte == 0xff) { 174 debug("%s: CROS_EC device not found on LPC bus\n", 175 __func__); 176 return -1; 177 } 178 179 return 0; 180 } 181 182 /* 183 * Test if LPC command args are supported. 184 * 185 * The cheapest way to do this is by looking for the memory-mapped 186 * flag. This is faster than sending a new-style 'hello' command and 187 * seeing whether the EC sets the EC_HOST_ARGS_FLAG_FROM_HOST flag 188 * in args when it responds. 189 */ 190 #ifdef CONFIG_DM_CROS_EC 191 static int cros_ec_lpc_check_version(struct udevice *dev) 192 #else 193 int cros_ec_lpc_check_version(struct cros_ec_dev *dev) 194 #endif 195 { 196 if (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) == 'E' && 197 inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) 198 == 'C' && 199 (inb(EC_LPC_ADDR_MEMMAP + 200 EC_MEMMAP_HOST_CMD_FLAGS) & 201 EC_HOST_CMD_FLAG_LPC_ARGS_SUPPORTED)) { 202 return 0; 203 } 204 205 printf("%s: ERROR: old EC interface not supported\n", __func__); 206 return -1; 207 } 208 209 #ifdef CONFIG_DM_CROS_EC 210 static int cros_ec_probe(struct udevice *dev) 211 { 212 return cros_ec_register(dev); 213 } 214 215 static struct dm_cros_ec_ops cros_ec_ops = { 216 .command = cros_ec_lpc_command, 217 .check_version = cros_ec_lpc_check_version, 218 }; 219 220 static const struct udevice_id cros_ec_ids[] = { 221 { .compatible = "google,cros-ec" }, 222 { } 223 }; 224 225 U_BOOT_DRIVER(cros_ec_lpc) = { 226 .name = "cros_ec", 227 .id = UCLASS_CROS_EC, 228 .of_match = cros_ec_ids, 229 .probe = cros_ec_probe, 230 .ops = &cros_ec_ops, 231 }; 232 #endif 233