1 // SPDX-License-Identifier: GPL-2.0 2 // 3 // Copyright 2018 Google LLC. 4 5 #include <linux/completion.h> 6 #include <linux/delay.h> 7 #include <linux/kernel.h> 8 #include <linux/module.h> 9 #include <linux/of.h> 10 #include <linux/platform_data/cros_ec_commands.h> 11 #include <linux/platform_data/cros_ec_proto.h> 12 #include <linux/platform_device.h> 13 #include <linux/rpmsg.h> 14 #include <linux/slab.h> 15 16 #include "cros_ec.h" 17 18 #define EC_MSG_TIMEOUT_MS 200 19 #define HOST_COMMAND_MARK 1 20 #define HOST_EVENT_MARK 2 21 22 /** 23 * struct cros_ec_rpmsg_response - rpmsg message format from from EC. 24 * 25 * @type: The type of message, should be either HOST_COMMAND_MARK or 26 * HOST_EVENT_MARK, representing that the message is a response to 27 * host command, or a host event. 28 * @data: ec_host_response for host command. 29 */ 30 struct cros_ec_rpmsg_response { 31 u8 type; 32 u8 data[] __aligned(4); 33 }; 34 35 /** 36 * struct cros_ec_rpmsg - information about a EC over rpmsg. 37 * 38 * @rpdev: rpmsg device we are connected to 39 * @xfer_ack: completion for host command transfer. 40 * @host_event_work: Work struct for pending host event. 41 * @ept: The rpmsg endpoint of this channel. 42 * @has_pending_host_event: Boolean used to check if there is a pending event. 43 * @probe_done: Flag to indicate that probe is done. 44 */ 45 struct cros_ec_rpmsg { 46 struct rpmsg_device *rpdev; 47 struct completion xfer_ack; 48 struct work_struct host_event_work; 49 struct rpmsg_endpoint *ept; 50 bool has_pending_host_event; 51 bool probe_done; 52 }; 53 54 /** 55 * cros_ec_cmd_xfer_rpmsg - Transfer a message over rpmsg and receive the reply 56 * 57 * @ec_dev: ChromeOS EC device 58 * @ec_msg: Message to transfer 59 * 60 * This is only used for old EC proto version, and is not supported for this 61 * driver. 62 * 63 * Return: -EINVAL 64 */ 65 static int cros_ec_cmd_xfer_rpmsg(struct cros_ec_device *ec_dev, 66 struct cros_ec_command *ec_msg) 67 { 68 return -EINVAL; 69 } 70 71 /** 72 * cros_ec_pkt_xfer_rpmsg - Transfer a packet over rpmsg and receive the reply 73 * 74 * @ec_dev: ChromeOS EC device 75 * @ec_msg: Message to transfer 76 * 77 * Return: number of bytes of the reply on success or negative error code. 78 */ 79 static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev, 80 struct cros_ec_command *ec_msg) 81 { 82 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv; 83 struct ec_host_response *response; 84 unsigned long timeout; 85 int len; 86 int ret; 87 u8 sum; 88 int i; 89 90 ec_msg->result = 0; 91 len = cros_ec_prepare_tx(ec_dev, ec_msg); 92 dev_dbg(ec_dev->dev, "prepared, len=%d\n", len); 93 94 reinit_completion(&ec_rpmsg->xfer_ack); 95 ret = rpmsg_send(ec_rpmsg->ept, ec_dev->dout, len); 96 if (ret) { 97 dev_err(ec_dev->dev, "rpmsg send failed\n"); 98 return ret; 99 } 100 101 timeout = msecs_to_jiffies(EC_MSG_TIMEOUT_MS); 102 ret = wait_for_completion_timeout(&ec_rpmsg->xfer_ack, timeout); 103 if (!ret) { 104 dev_err(ec_dev->dev, "rpmsg send timeout\n"); 105 return -EIO; 106 } 107 108 /* check response error code */ 109 response = (struct ec_host_response *)ec_dev->din; 110 ec_msg->result = response->result; 111 112 ret = cros_ec_check_result(ec_dev, ec_msg); 113 if (ret) 114 goto exit; 115 116 if (response->data_len > ec_msg->insize) { 117 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)", 118 response->data_len, ec_msg->insize); 119 ret = -EMSGSIZE; 120 goto exit; 121 } 122 123 /* copy response packet payload and compute checksum */ 124 memcpy(ec_msg->data, ec_dev->din + sizeof(*response), 125 response->data_len); 126 127 sum = 0; 128 for (i = 0; i < sizeof(*response) + response->data_len; i++) 129 sum += ec_dev->din[i]; 130 131 if (sum) { 132 dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n", 133 sum); 134 ret = -EBADMSG; 135 goto exit; 136 } 137 138 ret = response->data_len; 139 exit: 140 if (ec_msg->command == EC_CMD_REBOOT_EC) 141 msleep(EC_REBOOT_DELAY_MS); 142 143 return ret; 144 } 145 146 static void 147 cros_ec_rpmsg_host_event_function(struct work_struct *host_event_work) 148 { 149 struct cros_ec_rpmsg *ec_rpmsg = container_of(host_event_work, 150 struct cros_ec_rpmsg, 151 host_event_work); 152 struct cros_ec_device *ec_dev = dev_get_drvdata(&ec_rpmsg->rpdev->dev); 153 bool ec_has_more_events; 154 155 do { 156 ec_has_more_events = cros_ec_handle_event(ec_dev); 157 } while (ec_has_more_events); 158 } 159 160 static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data, 161 int len, void *priv, u32 src) 162 { 163 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev); 164 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv; 165 struct cros_ec_rpmsg_response *resp; 166 167 if (!len) { 168 dev_warn(ec_dev->dev, "rpmsg received empty response"); 169 return -EINVAL; 170 } 171 172 resp = data; 173 len -= offsetof(struct cros_ec_rpmsg_response, data); 174 if (resp->type == HOST_COMMAND_MARK) { 175 if (len > ec_dev->din_size) { 176 dev_warn(ec_dev->dev, 177 "received length %d > din_size %d, truncating", 178 len, ec_dev->din_size); 179 len = ec_dev->din_size; 180 } 181 182 memcpy(ec_dev->din, resp->data, len); 183 complete(&ec_rpmsg->xfer_ack); 184 } else if (resp->type == HOST_EVENT_MARK) { 185 /* 186 * If the host event is sent before cros_ec_register is 187 * finished, queue the host event. 188 */ 189 if (ec_rpmsg->probe_done) 190 schedule_work(&ec_rpmsg->host_event_work); 191 else 192 ec_rpmsg->has_pending_host_event = true; 193 } else { 194 dev_warn(ec_dev->dev, "rpmsg received invalid type = %d", 195 resp->type); 196 return -EINVAL; 197 } 198 199 return 0; 200 } 201 202 static struct rpmsg_endpoint * 203 cros_ec_rpmsg_create_ept(struct rpmsg_device *rpdev) 204 { 205 struct rpmsg_channel_info chinfo = {}; 206 207 strscpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE); 208 chinfo.src = rpdev->src; 209 chinfo.dst = RPMSG_ADDR_ANY; 210 211 return rpmsg_create_ept(rpdev, cros_ec_rpmsg_callback, NULL, chinfo); 212 } 213 214 static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev) 215 { 216 struct device *dev = &rpdev->dev; 217 struct cros_ec_rpmsg *ec_rpmsg; 218 struct cros_ec_device *ec_dev; 219 int ret; 220 221 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); 222 if (!ec_dev) 223 return -ENOMEM; 224 225 ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL); 226 if (!ec_rpmsg) 227 return -ENOMEM; 228 229 ec_dev->dev = dev; 230 ec_dev->priv = ec_rpmsg; 231 ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg; 232 ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg; 233 ec_dev->phys_name = dev_name(&rpdev->dev); 234 ec_dev->din_size = sizeof(struct ec_host_response) + 235 sizeof(struct ec_response_get_protocol_info); 236 ec_dev->dout_size = sizeof(struct ec_host_request); 237 dev_set_drvdata(dev, ec_dev); 238 239 ec_rpmsg->rpdev = rpdev; 240 init_completion(&ec_rpmsg->xfer_ack); 241 INIT_WORK(&ec_rpmsg->host_event_work, 242 cros_ec_rpmsg_host_event_function); 243 244 ec_rpmsg->ept = cros_ec_rpmsg_create_ept(rpdev); 245 if (!ec_rpmsg->ept) 246 return -ENOMEM; 247 248 ret = cros_ec_register(ec_dev); 249 if (ret < 0) { 250 rpmsg_destroy_ept(ec_rpmsg->ept); 251 cancel_work_sync(&ec_rpmsg->host_event_work); 252 return ret; 253 } 254 255 ec_rpmsg->probe_done = true; 256 257 if (ec_rpmsg->has_pending_host_event) 258 schedule_work(&ec_rpmsg->host_event_work); 259 260 return 0; 261 } 262 263 static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev) 264 { 265 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev); 266 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv; 267 268 cros_ec_unregister(ec_dev); 269 rpmsg_destroy_ept(ec_rpmsg->ept); 270 cancel_work_sync(&ec_rpmsg->host_event_work); 271 } 272 273 #ifdef CONFIG_PM_SLEEP 274 static int cros_ec_rpmsg_suspend(struct device *dev) 275 { 276 struct cros_ec_device *ec_dev = dev_get_drvdata(dev); 277 278 return cros_ec_suspend(ec_dev); 279 } 280 281 static int cros_ec_rpmsg_resume(struct device *dev) 282 { 283 struct cros_ec_device *ec_dev = dev_get_drvdata(dev); 284 285 return cros_ec_resume(ec_dev); 286 } 287 #endif 288 289 static SIMPLE_DEV_PM_OPS(cros_ec_rpmsg_pm_ops, cros_ec_rpmsg_suspend, 290 cros_ec_rpmsg_resume); 291 292 static const struct of_device_id cros_ec_rpmsg_of_match[] = { 293 { .compatible = "google,cros-ec-rpmsg", }, 294 { } 295 }; 296 MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match); 297 298 static struct rpmsg_driver cros_ec_driver_rpmsg = { 299 .drv = { 300 .name = "cros-ec-rpmsg", 301 .of_match_table = cros_ec_rpmsg_of_match, 302 .pm = &cros_ec_rpmsg_pm_ops, 303 }, 304 .probe = cros_ec_rpmsg_probe, 305 .remove = cros_ec_rpmsg_remove, 306 }; 307 308 module_rpmsg_driver(cros_ec_driver_rpmsg); 309 310 MODULE_LICENSE("GPL v2"); 311 MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)"); 312