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