Bill Richardson | ec2f33a | 2015-02-02 12:26:24 +0100 | [diff] [blame] | 1 | /* |
| 2 | * cros_ec_lpc - LPC access to the Chrome OS Embedded Controller |
| 3 | * |
| 4 | * Copyright (C) 2012-2015 Google, Inc |
| 5 | * |
| 6 | * This software is licensed under the terms of the GNU General Public |
| 7 | * License version 2, as published by the Free Software Foundation, and |
| 8 | * may be copied, distributed, and modified under those terms. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * This driver uses the Chrome OS EC byte-level message-based protocol for |
| 16 | * communicating the keyboard state (which keys are pressed) from a keyboard EC |
| 17 | * to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing, |
| 18 | * but everything else (including deghosting) is done here. The main |
| 19 | * motivation for this is to keep the EC firmware as simple as possible, since |
| 20 | * it cannot be easily upgraded and EC flash/IRAM space is relatively |
| 21 | * expensive. |
| 22 | */ |
| 23 | |
| 24 | #include <linux/dmi.h> |
| 25 | #include <linux/delay.h> |
Javier Martinez Canillas | 18d0dc2 | 2015-02-27 06:37:48 +0100 | [diff] [blame] | 26 | #include <linux/io.h> |
Bill Richardson | ec2f33a | 2015-02-02 12:26:24 +0100 | [diff] [blame] | 27 | #include <linux/mfd/cros_ec.h> |
| 28 | #include <linux/mfd/cros_ec_commands.h> |
| 29 | #include <linux/module.h> |
| 30 | #include <linux/platform_device.h> |
| 31 | #include <linux/printk.h> |
| 32 | |
| 33 | #define DRV_NAME "cros_ec_lpc" |
| 34 | |
| 35 | static int ec_response_timed_out(void) |
| 36 | { |
| 37 | unsigned long one_second = jiffies + HZ; |
| 38 | |
| 39 | usleep_range(200, 300); |
| 40 | do { |
| 41 | if (!(inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK)) |
| 42 | return 0; |
| 43 | usleep_range(100, 200); |
| 44 | } while (time_before(jiffies, one_second)); |
| 45 | |
| 46 | return 1; |
| 47 | } |
| 48 | |
Stephen Barber | d365407 | 2015-06-09 13:04:46 +0200 | [diff] [blame] | 49 | static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec, |
| 50 | struct cros_ec_command *msg) |
| 51 | { |
| 52 | struct ec_host_request *request; |
| 53 | struct ec_host_response response; |
| 54 | u8 sum = 0; |
| 55 | int i; |
| 56 | int ret = 0; |
| 57 | u8 *dout; |
| 58 | |
| 59 | ret = cros_ec_prepare_tx(ec, msg); |
| 60 | |
| 61 | /* Write buffer */ |
| 62 | for (i = 0; i < ret; i++) |
| 63 | outb(ec->dout[i], EC_LPC_ADDR_HOST_PACKET + i); |
| 64 | |
| 65 | request = (struct ec_host_request *)ec->dout; |
| 66 | |
| 67 | /* Here we go */ |
| 68 | outb(EC_COMMAND_PROTOCOL_3, EC_LPC_ADDR_HOST_CMD); |
| 69 | |
| 70 | if (ec_response_timed_out()) { |
| 71 | dev_warn(ec->dev, "EC responsed timed out\n"); |
| 72 | ret = -EIO; |
| 73 | goto done; |
| 74 | } |
| 75 | |
| 76 | /* Check result */ |
| 77 | msg->result = inb(EC_LPC_ADDR_HOST_DATA); |
| 78 | ret = cros_ec_check_result(ec, msg); |
| 79 | if (ret) |
| 80 | goto done; |
| 81 | |
| 82 | /* Read back response */ |
| 83 | dout = (u8 *)&response; |
| 84 | for (i = 0; i < sizeof(response); i++) { |
| 85 | dout[i] = inb(EC_LPC_ADDR_HOST_PACKET + i); |
| 86 | sum += dout[i]; |
| 87 | } |
| 88 | |
| 89 | msg->result = response.result; |
| 90 | |
| 91 | if (response.data_len > msg->insize) { |
| 92 | dev_err(ec->dev, |
| 93 | "packet too long (%d bytes, expected %d)", |
| 94 | response.data_len, msg->insize); |
| 95 | ret = -EMSGSIZE; |
| 96 | goto done; |
| 97 | } |
| 98 | |
| 99 | /* Read response and process checksum */ |
| 100 | for (i = 0; i < response.data_len; i++) { |
| 101 | msg->data[i] = |
| 102 | inb(EC_LPC_ADDR_HOST_PACKET + sizeof(response) + i); |
| 103 | sum += msg->data[i]; |
| 104 | } |
| 105 | |
| 106 | if (sum) { |
| 107 | dev_err(ec->dev, |
| 108 | "bad packet checksum %02x\n", |
| 109 | response.checksum); |
| 110 | ret = -EBADMSG; |
| 111 | goto done; |
| 112 | } |
| 113 | |
| 114 | /* Return actual amount of data received */ |
| 115 | ret = response.data_len; |
| 116 | done: |
| 117 | return ret; |
| 118 | } |
| 119 | |
Bill Richardson | ec2f33a | 2015-02-02 12:26:24 +0100 | [diff] [blame] | 120 | static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec, |
| 121 | struct cros_ec_command *msg) |
| 122 | { |
| 123 | struct ec_lpc_host_args args; |
| 124 | int csum; |
| 125 | int i; |
| 126 | int ret = 0; |
| 127 | |
| 128 | if (msg->outsize > EC_PROTO2_MAX_PARAM_SIZE || |
| 129 | msg->insize > EC_PROTO2_MAX_PARAM_SIZE) { |
| 130 | dev_err(ec->dev, |
| 131 | "invalid buffer sizes (out %d, in %d)\n", |
| 132 | msg->outsize, msg->insize); |
| 133 | return -EINVAL; |
| 134 | } |
| 135 | |
| 136 | /* Now actually send the command to the EC and get the result */ |
| 137 | args.flags = EC_HOST_ARGS_FLAG_FROM_HOST; |
| 138 | args.command_version = msg->version; |
| 139 | args.data_size = msg->outsize; |
| 140 | |
| 141 | /* Initialize checksum */ |
| 142 | csum = msg->command + args.flags + |
| 143 | args.command_version + args.data_size; |
| 144 | |
| 145 | /* Copy data and update checksum */ |
| 146 | for (i = 0; i < msg->outsize; i++) { |
Javier Martinez Canillas | a841178 | 2015-06-09 13:04:42 +0200 | [diff] [blame] | 147 | outb(msg->data[i], EC_LPC_ADDR_HOST_PARAM + i); |
| 148 | csum += msg->data[i]; |
Bill Richardson | ec2f33a | 2015-02-02 12:26:24 +0100 | [diff] [blame] | 149 | } |
| 150 | |
| 151 | /* Finalize checksum and write args */ |
| 152 | args.checksum = csum & 0xFF; |
| 153 | outb(args.flags, EC_LPC_ADDR_HOST_ARGS); |
| 154 | outb(args.command_version, EC_LPC_ADDR_HOST_ARGS + 1); |
| 155 | outb(args.data_size, EC_LPC_ADDR_HOST_ARGS + 2); |
| 156 | outb(args.checksum, EC_LPC_ADDR_HOST_ARGS + 3); |
| 157 | |
| 158 | /* Here we go */ |
| 159 | outb(msg->command, EC_LPC_ADDR_HOST_CMD); |
| 160 | |
| 161 | if (ec_response_timed_out()) { |
| 162 | dev_warn(ec->dev, "EC responsed timed out\n"); |
| 163 | ret = -EIO; |
| 164 | goto done; |
| 165 | } |
| 166 | |
| 167 | /* Check result */ |
| 168 | msg->result = inb(EC_LPC_ADDR_HOST_DATA); |
| 169 | |
| 170 | switch (msg->result) { |
| 171 | case EC_RES_SUCCESS: |
| 172 | break; |
| 173 | case EC_RES_IN_PROGRESS: |
| 174 | ret = -EAGAIN; |
| 175 | dev_dbg(ec->dev, "command 0x%02x in progress\n", |
| 176 | msg->command); |
| 177 | goto done; |
| 178 | default: |
| 179 | dev_dbg(ec->dev, "command 0x%02x returned %d\n", |
| 180 | msg->command, msg->result); |
| 181 | } |
| 182 | |
| 183 | /* Read back args */ |
| 184 | args.flags = inb(EC_LPC_ADDR_HOST_ARGS); |
| 185 | args.command_version = inb(EC_LPC_ADDR_HOST_ARGS + 1); |
| 186 | args.data_size = inb(EC_LPC_ADDR_HOST_ARGS + 2); |
| 187 | args.checksum = inb(EC_LPC_ADDR_HOST_ARGS + 3); |
| 188 | |
| 189 | if (args.data_size > msg->insize) { |
| 190 | dev_err(ec->dev, |
| 191 | "packet too long (%d bytes, expected %d)", |
| 192 | args.data_size, msg->insize); |
| 193 | ret = -ENOSPC; |
| 194 | goto done; |
| 195 | } |
| 196 | |
| 197 | /* Start calculating response checksum */ |
| 198 | csum = msg->command + args.flags + |
| 199 | args.command_version + args.data_size; |
| 200 | |
| 201 | /* Read response and update checksum */ |
| 202 | for (i = 0; i < args.data_size; i++) { |
Javier Martinez Canillas | a841178 | 2015-06-09 13:04:42 +0200 | [diff] [blame] | 203 | msg->data[i] = inb(EC_LPC_ADDR_HOST_PARAM + i); |
| 204 | csum += msg->data[i]; |
Bill Richardson | ec2f33a | 2015-02-02 12:26:24 +0100 | [diff] [blame] | 205 | } |
| 206 | |
| 207 | /* Verify checksum */ |
| 208 | if (args.checksum != (csum & 0xFF)) { |
| 209 | dev_err(ec->dev, |
| 210 | "bad packet checksum, expected %02x, got %02x\n", |
| 211 | args.checksum, csum & 0xFF); |
| 212 | ret = -EBADMSG; |
| 213 | goto done; |
| 214 | } |
| 215 | |
| 216 | /* Return actual amount of data received */ |
| 217 | ret = args.data_size; |
| 218 | done: |
| 219 | return ret; |
| 220 | } |
| 221 | |
| 222 | /* Returns num bytes read, or negative on error. Doesn't need locking. */ |
| 223 | static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset, |
| 224 | unsigned int bytes, void *dest) |
| 225 | { |
| 226 | int i = offset; |
| 227 | char *s = dest; |
| 228 | int cnt = 0; |
| 229 | |
| 230 | if (offset >= EC_MEMMAP_SIZE - bytes) |
| 231 | return -EINVAL; |
| 232 | |
| 233 | /* fixed length */ |
| 234 | if (bytes) { |
| 235 | for (; cnt < bytes; i++, s++, cnt++) |
| 236 | *s = inb(EC_LPC_ADDR_MEMMAP + i); |
| 237 | return cnt; |
| 238 | } |
| 239 | |
| 240 | /* string */ |
| 241 | for (; i < EC_MEMMAP_SIZE; i++, s++) { |
| 242 | *s = inb(EC_LPC_ADDR_MEMMAP + i); |
| 243 | cnt++; |
| 244 | if (!*s) |
| 245 | break; |
| 246 | } |
| 247 | |
| 248 | return cnt; |
| 249 | } |
| 250 | |
| 251 | static int cros_ec_lpc_probe(struct platform_device *pdev) |
| 252 | { |
| 253 | struct device *dev = &pdev->dev; |
| 254 | struct cros_ec_device *ec_dev; |
| 255 | int ret; |
| 256 | |
| 257 | if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE, |
| 258 | dev_name(dev))) { |
| 259 | dev_err(dev, "couldn't reserve memmap region\n"); |
| 260 | return -EBUSY; |
| 261 | } |
| 262 | |
| 263 | if ((inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) != 'E') || |
| 264 | (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) != 'C')) { |
| 265 | dev_err(dev, "EC ID not detected\n"); |
| 266 | return -ENODEV; |
| 267 | } |
| 268 | |
| 269 | if (!devm_request_region(dev, EC_HOST_CMD_REGION0, |
| 270 | EC_HOST_CMD_REGION_SIZE, dev_name(dev))) { |
| 271 | dev_err(dev, "couldn't reserve region0\n"); |
| 272 | return -EBUSY; |
| 273 | } |
| 274 | if (!devm_request_region(dev, EC_HOST_CMD_REGION1, |
| 275 | EC_HOST_CMD_REGION_SIZE, dev_name(dev))) { |
| 276 | dev_err(dev, "couldn't reserve region1\n"); |
| 277 | return -EBUSY; |
| 278 | } |
| 279 | |
| 280 | ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); |
| 281 | if (!ec_dev) |
| 282 | return -ENOMEM; |
| 283 | |
| 284 | platform_set_drvdata(pdev, ec_dev); |
| 285 | ec_dev->dev = dev; |
Bill Richardson | ec2f33a | 2015-02-02 12:26:24 +0100 | [diff] [blame] | 286 | ec_dev->phys_name = dev_name(dev); |
Bill Richardson | ec2f33a | 2015-02-02 12:26:24 +0100 | [diff] [blame] | 287 | ec_dev->cmd_xfer = cros_ec_cmd_xfer_lpc; |
Stephen Barber | d365407 | 2015-06-09 13:04:46 +0200 | [diff] [blame] | 288 | ec_dev->pkt_xfer = cros_ec_pkt_xfer_lpc; |
Bill Richardson | ec2f33a | 2015-02-02 12:26:24 +0100 | [diff] [blame] | 289 | ec_dev->cmd_readmem = cros_ec_lpc_readmem; |
Stephen Barber | 2c7589a | 2015-06-09 13:04:45 +0200 | [diff] [blame] | 290 | ec_dev->din_size = sizeof(struct ec_host_response) + |
| 291 | sizeof(struct ec_response_get_protocol_info); |
| 292 | ec_dev->dout_size = sizeof(struct ec_host_request); |
Bill Richardson | ec2f33a | 2015-02-02 12:26:24 +0100 | [diff] [blame] | 293 | |
| 294 | ret = cros_ec_register(ec_dev); |
| 295 | if (ret) { |
| 296 | dev_err(dev, "couldn't register ec_dev (%d)\n", ret); |
| 297 | return ret; |
| 298 | } |
| 299 | |
| 300 | return 0; |
| 301 | } |
| 302 | |
| 303 | static int cros_ec_lpc_remove(struct platform_device *pdev) |
| 304 | { |
| 305 | struct cros_ec_device *ec_dev; |
| 306 | |
| 307 | ec_dev = platform_get_drvdata(pdev); |
| 308 | cros_ec_remove(ec_dev); |
| 309 | |
| 310 | return 0; |
| 311 | } |
| 312 | |
| 313 | static struct dmi_system_id cros_ec_lpc_dmi_table[] __initdata = { |
| 314 | { |
| 315 | /* |
| 316 | * Today all Chromebooks/boxes ship with Google_* as version and |
| 317 | * coreboot as bios vendor. No other systems with this |
| 318 | * combination are known to date. |
| 319 | */ |
| 320 | .matches = { |
| 321 | DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"), |
| 322 | DMI_MATCH(DMI_BIOS_VERSION, "Google_"), |
| 323 | }, |
| 324 | }, |
| 325 | { |
| 326 | /* x86-link, the Chromebook Pixel. */ |
| 327 | .matches = { |
| 328 | DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"), |
| 329 | DMI_MATCH(DMI_PRODUCT_NAME, "Link"), |
| 330 | }, |
| 331 | }, |
| 332 | { |
| 333 | /* x86-peppy, the Acer C720 Chromebook. */ |
| 334 | .matches = { |
| 335 | DMI_MATCH(DMI_SYS_VENDOR, "Acer"), |
| 336 | DMI_MATCH(DMI_PRODUCT_NAME, "Peppy"), |
| 337 | }, |
| 338 | }, |
| 339 | { /* sentinel */ } |
| 340 | }; |
| 341 | MODULE_DEVICE_TABLE(dmi, cros_ec_lpc_dmi_table); |
| 342 | |
| 343 | static struct platform_driver cros_ec_lpc_driver = { |
| 344 | .driver = { |
| 345 | .name = DRV_NAME, |
Bill Richardson | ec2f33a | 2015-02-02 12:26:24 +0100 | [diff] [blame] | 346 | }, |
| 347 | .probe = cros_ec_lpc_probe, |
| 348 | .remove = cros_ec_lpc_remove, |
| 349 | }; |
| 350 | |
| 351 | static struct platform_device cros_ec_lpc_device = { |
| 352 | .name = DRV_NAME |
| 353 | }; |
| 354 | |
| 355 | static int __init cros_ec_lpc_init(void) |
| 356 | { |
| 357 | int ret; |
| 358 | |
| 359 | if (!dmi_check_system(cros_ec_lpc_dmi_table)) { |
| 360 | pr_err(DRV_NAME ": unsupported system.\n"); |
| 361 | return -ENODEV; |
| 362 | } |
| 363 | |
| 364 | /* Register the driver */ |
| 365 | ret = platform_driver_register(&cros_ec_lpc_driver); |
| 366 | if (ret) { |
| 367 | pr_err(DRV_NAME ": can't register driver: %d\n", ret); |
| 368 | return ret; |
| 369 | } |
| 370 | |
| 371 | /* Register the device, and it'll get hooked up automatically */ |
| 372 | ret = platform_device_register(&cros_ec_lpc_device); |
| 373 | if (ret) { |
| 374 | pr_err(DRV_NAME ": can't register device: %d\n", ret); |
| 375 | platform_driver_unregister(&cros_ec_lpc_driver); |
| 376 | return ret; |
| 377 | } |
| 378 | |
| 379 | return 0; |
| 380 | } |
| 381 | |
| 382 | static void __exit cros_ec_lpc_exit(void) |
| 383 | { |
| 384 | platform_device_unregister(&cros_ec_lpc_device); |
| 385 | platform_driver_unregister(&cros_ec_lpc_driver); |
| 386 | } |
| 387 | |
| 388 | module_init(cros_ec_lpc_init); |
| 389 | module_exit(cros_ec_lpc_exit); |
| 390 | |
| 391 | MODULE_LICENSE("GPL"); |
| 392 | MODULE_DESCRIPTION("ChromeOS EC LPC driver"); |