1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * UCSI driver for ChromeOS EC 4 * 5 * Copyright 2024 Google LLC. 6 */ 7 8 #include <linux/acpi.h> 9 #include <linux/container_of.h> 10 #include <linux/dev_printk.h> 11 #include <linux/jiffies.h> 12 #include <linux/mod_devicetable.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 #include <linux/platform_data/cros_ec_commands.h> 16 #include <linux/platform_data/cros_usbpd_notify.h> 17 #include <linux/platform_data/cros_ec_proto.h> 18 #include <linux/platform_device.h> 19 #include <linux/slab.h> 20 #include <linux/wait.h> 21 #include <linux/usb/typec_altmode.h> 22 23 #include "ucsi.h" 24 25 /* 26 * Maximum size in bytes of a UCSI message between AP and EC 27 */ 28 #define MAX_EC_DATA_SIZE 256 29 30 /* 31 * Maximum time in milliseconds the cros_ec_ucsi driver 32 * will wait for a response to a command or and ack. 33 */ 34 #define WRITE_TMO_MS 5000 35 36 /* Number of times to attempt recovery from a write timeout before giving up. */ 37 #define WRITE_TMO_CTR_MAX 5 38 39 /* Delay between mode entry/exit attempts, ms */ 40 static const unsigned int mode_selection_delay = 1000; 41 /* Timeout for a mode entry attempt, ms */ 42 static const unsigned int mode_selection_timeout = 4000; 43 44 struct cros_ucsi_data { 45 struct device *dev; 46 struct ucsi *ucsi; 47 48 struct cros_ec_device *ec; 49 struct notifier_block nb; 50 struct work_struct work; 51 struct delayed_work write_tmo; 52 int tmo_counter; 53 54 struct completion complete; 55 unsigned long flags; 56 }; 57 58 static int cros_ucsi_read(struct ucsi *ucsi, unsigned int offset, void *val, 59 size_t val_len) 60 { 61 struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi); 62 struct ec_params_ucsi_ppm_get req = { 63 .offset = offset, 64 .size = val_len, 65 }; 66 int ret; 67 68 if (val_len > MAX_EC_DATA_SIZE) { 69 dev_err(udata->dev, "Can't read %zu bytes. Too big.\n", val_len); 70 return -EINVAL; 71 } 72 73 ret = cros_ec_cmd(udata->ec, 0, EC_CMD_UCSI_PPM_GET, 74 &req, sizeof(req), val, val_len); 75 if (ret < 0) { 76 dev_warn(udata->dev, "Failed to send EC message UCSI_PPM_GET: error=%d\n", ret); 77 return ret; 78 } 79 return 0; 80 } 81 82 static int cros_ucsi_read_version(struct ucsi *ucsi, u16 *version) 83 { 84 return cros_ucsi_read(ucsi, UCSI_VERSION, version, sizeof(*version)); 85 } 86 87 static int cros_ucsi_read_cci(struct ucsi *ucsi, u32 *cci) 88 { 89 return cros_ucsi_read(ucsi, UCSI_CCI, cci, sizeof(*cci)); 90 } 91 92 static int cros_ucsi_read_message_in(struct ucsi *ucsi, void *val, 93 size_t val_len) 94 { 95 return cros_ucsi_read(ucsi, UCSI_MESSAGE_IN, val, val_len); 96 } 97 98 static int cros_ucsi_async_control(struct ucsi *ucsi, u64 cmd) 99 { 100 struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi); 101 u8 ec_buf[sizeof(struct ec_params_ucsi_ppm_set) + sizeof(cmd)]; 102 struct ec_params_ucsi_ppm_set *req = (struct ec_params_ucsi_ppm_set *) ec_buf; 103 int ret; 104 105 req->offset = UCSI_CONTROL; 106 memcpy(req->data, &cmd, sizeof(cmd)); 107 ret = cros_ec_cmd(udata->ec, 0, EC_CMD_UCSI_PPM_SET, 108 req, sizeof(ec_buf), NULL, 0); 109 if (ret < 0) { 110 dev_warn(udata->dev, "Failed to send EC message UCSI_PPM_SET: error=%d\n", ret); 111 return ret; 112 } 113 return 0; 114 } 115 116 static int cros_ucsi_sync_control(struct ucsi *ucsi, u64 cmd, u32 *cci, 117 void *data, size_t size) 118 { 119 struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi); 120 int ret; 121 122 ret = ucsi_sync_control_common(ucsi, cmd, cci, data, size); 123 switch (ret) { 124 case -EBUSY: 125 /* EC may return -EBUSY if CCI.busy is set. 126 * Convert this to a timeout. 127 */ 128 case -ETIMEDOUT: 129 /* Schedule recovery attempt when we timeout 130 * or tried to send a command while still busy. 131 */ 132 cancel_delayed_work_sync(&udata->write_tmo); 133 schedule_delayed_work(&udata->write_tmo, 134 msecs_to_jiffies(WRITE_TMO_MS)); 135 break; 136 case 0: 137 /* Successful write. Cancel any pending recovery work. */ 138 cancel_delayed_work_sync(&udata->write_tmo); 139 break; 140 } 141 142 return ret; 143 } 144 145 static void cros_ucsi_add_partner_altmodes(struct ucsi_connector *con) 146 { 147 if (!con->typec_cap.no_mode_control) 148 typec_mode_selection_start(con->partner, 149 mode_selection_delay, 150 mode_selection_timeout); 151 } 152 153 static void cros_ucsi_remove_partner_altmodes(struct ucsi_connector *con) 154 { 155 if (!con->typec_cap.no_mode_control) 156 typec_mode_selection_delete(con->partner); 157 } 158 159 static const struct ucsi_operations cros_ucsi_ops = { 160 .read_version = cros_ucsi_read_version, 161 .read_cci = cros_ucsi_read_cci, 162 .poll_cci = cros_ucsi_read_cci, 163 .read_message_in = cros_ucsi_read_message_in, 164 .async_control = cros_ucsi_async_control, 165 .sync_control = cros_ucsi_sync_control, 166 .add_partner_altmodes = cros_ucsi_add_partner_altmodes, 167 .remove_partner_altmodes = cros_ucsi_remove_partner_altmodes, 168 }; 169 170 static void cros_ucsi_work(struct work_struct *work) 171 { 172 struct cros_ucsi_data *udata = container_of(work, struct cros_ucsi_data, work); 173 u32 cci; 174 175 if (cros_ucsi_read_cci(udata->ucsi, &cci)) 176 return; 177 178 ucsi_notify_common(udata->ucsi, cci); 179 } 180 181 static void cros_ucsi_write_timeout(struct work_struct *work) 182 { 183 struct cros_ucsi_data *udata = 184 container_of(work, struct cros_ucsi_data, write_tmo.work); 185 u32 cci; 186 u64 cmd; 187 188 if (cros_ucsi_read(udata->ucsi, UCSI_CCI, &cci, sizeof(cci))) { 189 dev_err(udata->dev, 190 "Reading CCI failed; no write timeout recovery possible.\n"); 191 return; 192 } 193 194 if (cci & UCSI_CCI_BUSY) { 195 udata->tmo_counter++; 196 197 if (udata->tmo_counter <= WRITE_TMO_CTR_MAX) 198 schedule_delayed_work(&udata->write_tmo, 199 msecs_to_jiffies(WRITE_TMO_MS)); 200 else 201 dev_err(udata->dev, 202 "PPM unresponsive - too many write timeouts.\n"); 203 204 return; 205 } 206 207 /* No longer busy means we can reset our timeout counter. */ 208 udata->tmo_counter = 0; 209 210 /* Need to ack previous command which may have timed out. */ 211 if (cci & UCSI_CCI_COMMAND_COMPLETE) { 212 cmd = UCSI_ACK_CC_CI | UCSI_ACK_COMMAND_COMPLETE; 213 cros_ucsi_async_control(udata->ucsi, cmd); 214 215 /* Check again after a few seconds that the system has 216 * recovered to make sure our async write above was successful. 217 */ 218 schedule_delayed_work(&udata->write_tmo, 219 msecs_to_jiffies(WRITE_TMO_MS)); 220 return; 221 } 222 223 /* We recovered from a previous timeout. Treat this as a recovery from 224 * suspend and call resume. 225 */ 226 ucsi_resume(udata->ucsi); 227 } 228 229 static int cros_ucsi_event(struct notifier_block *nb, 230 unsigned long host_event, void *_notify) 231 { 232 struct cros_ucsi_data *udata = container_of(nb, struct cros_ucsi_data, nb); 233 234 if (host_event & PD_EVENT_INIT) { 235 /* Late init event received from ChromeOS EC. Treat this as a 236 * system resume to re-enable communication with the PPM. 237 */ 238 dev_dbg(udata->dev, "Late PD init received\n"); 239 ucsi_resume(udata->ucsi); 240 } 241 242 if (host_event & PD_EVENT_PPM) { 243 dev_dbg(udata->dev, "UCSI notification received\n"); 244 flush_work(&udata->work); 245 schedule_work(&udata->work); 246 } 247 248 return NOTIFY_OK; 249 } 250 251 static void cros_ucsi_destroy(struct cros_ucsi_data *udata) 252 { 253 cros_usbpd_unregister_notify(&udata->nb); 254 cancel_delayed_work_sync(&udata->write_tmo); 255 cancel_work_sync(&udata->work); 256 ucsi_destroy(udata->ucsi); 257 } 258 259 static int cros_ucsi_probe(struct platform_device *pdev) 260 { 261 struct device *dev = &pdev->dev; 262 struct cros_ucsi_data *udata; 263 int ret; 264 265 udata = devm_kzalloc(dev, sizeof(*udata), GFP_KERNEL); 266 if (!udata) 267 return -ENOMEM; 268 269 /* ACPI and OF FW nodes for cros_ec_ucsi are children of the ChromeOS EC. If the 270 * cros_ec_ucsi device has an ACPI or OF FW node, its parent is the ChromeOS EC device. 271 * Platforms without a FW node for cros_ec_ucsi may add it as a subdevice of cros_ec_dev. 272 */ 273 udata->dev = dev; 274 if (is_acpi_device_node(dev->fwnode) || is_of_node(dev->fwnode)) 275 udata->ec = dev_get_drvdata(dev->parent); 276 else 277 udata->ec = ((struct cros_ec_dev *)dev_get_drvdata(dev->parent))->ec_dev; 278 279 if (!udata->ec) 280 return dev_err_probe(dev, -ENODEV, "couldn't find parent EC device\n"); 281 282 platform_set_drvdata(pdev, udata); 283 284 INIT_WORK(&udata->work, cros_ucsi_work); 285 INIT_DELAYED_WORK(&udata->write_tmo, cros_ucsi_write_timeout); 286 init_completion(&udata->complete); 287 288 udata->ucsi = ucsi_create(dev, &cros_ucsi_ops); 289 if (IS_ERR(udata->ucsi)) 290 return dev_err_probe(dev, PTR_ERR(udata->ucsi), "failed to allocate UCSI instance\n"); 291 292 ucsi_set_drvdata(udata->ucsi, udata); 293 294 udata->nb.notifier_call = cros_ucsi_event; 295 ret = cros_usbpd_register_notify(&udata->nb); 296 if (ret) { 297 dev_err_probe(dev, ret, "failed to register notifier\n"); 298 ucsi_destroy(udata->ucsi); 299 return ret; 300 } 301 302 ret = ucsi_register(udata->ucsi); 303 if (ret) { 304 dev_err_probe(dev, ret, "failed to register UCSI\n"); 305 cros_ucsi_destroy(udata); 306 return ret; 307 } 308 309 return 0; 310 } 311 312 static void cros_ucsi_remove(struct platform_device *dev) 313 { 314 struct cros_ucsi_data *udata = platform_get_drvdata(dev); 315 316 ucsi_unregister(udata->ucsi); 317 cros_ucsi_destroy(udata); 318 } 319 320 static int __maybe_unused cros_ucsi_suspend(struct device *dev) 321 { 322 struct cros_ucsi_data *udata = dev_get_drvdata(dev); 323 324 cancel_delayed_work_sync(&udata->write_tmo); 325 cancel_work_sync(&udata->work); 326 327 return 0; 328 } 329 330 static void __maybe_unused cros_ucsi_complete(struct device *dev) 331 { 332 struct cros_ucsi_data *udata = dev_get_drvdata(dev); 333 334 ucsi_resume(udata->ucsi); 335 } 336 337 /* 338 * UCSI protocol is also used on ChromeOS platforms which reply on 339 * cros_ec_lpc.c driver for communication with embedded controller (EC). 340 * On such platforms communication with the EC is not available until 341 * the .complete() callback of the cros_ec_lpc driver is executed. 342 * For this reason we delay ucsi_resume() until the .complete() stage 343 * otherwise UCSI SET_NOTIFICATION_ENABLE command will fail and we won't 344 * receive any UCSI notifications from the EC where PPM is implemented. 345 */ 346 static const struct dev_pm_ops cros_ucsi_pm_ops = { 347 #ifdef CONFIG_PM_SLEEP 348 .suspend = cros_ucsi_suspend, 349 .complete = cros_ucsi_complete, 350 #endif 351 }; 352 353 static const struct platform_device_id cros_ucsi_id[] = { 354 { KBUILD_MODNAME, 0 }, 355 {} 356 }; 357 MODULE_DEVICE_TABLE(platform, cros_ucsi_id); 358 359 static const struct acpi_device_id cros_ec_ucsi_acpi_device_ids[] = { 360 { "GOOG0021", 0 }, 361 { } 362 }; 363 MODULE_DEVICE_TABLE(acpi, cros_ec_ucsi_acpi_device_ids); 364 365 static const struct of_device_id cros_ucsi_of_match[] = { 366 { .compatible = "google,cros-ec-ucsi", }, 367 {} 368 }; 369 MODULE_DEVICE_TABLE(of, cros_ucsi_of_match); 370 371 static struct platform_driver cros_ucsi_driver = { 372 .driver = { 373 .name = KBUILD_MODNAME, 374 .pm = &cros_ucsi_pm_ops, 375 .acpi_match_table = cros_ec_ucsi_acpi_device_ids, 376 .of_match_table = cros_ucsi_of_match, 377 }, 378 .id_table = cros_ucsi_id, 379 .probe = cros_ucsi_probe, 380 .remove = cros_ucsi_remove, 381 }; 382 383 module_platform_driver(cros_ucsi_driver); 384 385 MODULE_LICENSE("GPL"); 386 MODULE_DESCRIPTION("UCSI driver for ChromeOS EC"); 387