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 if (len < 0) 93 return len; 94 dev_dbg(ec_dev->dev, "prepared, len=%d\n", len); 95 96 reinit_completion(&ec_rpmsg->xfer_ack); 97 ret = rpmsg_send(ec_rpmsg->ept, ec_dev->dout, len); 98 if (ret) { 99 dev_err(ec_dev->dev, "rpmsg send failed\n"); 100 return ret; 101 } 102 103 timeout = msecs_to_jiffies(EC_MSG_TIMEOUT_MS); 104 ret = wait_for_completion_timeout(&ec_rpmsg->xfer_ack, timeout); 105 if (!ret) { 106 dev_err(ec_dev->dev, "rpmsg send timeout\n"); 107 return -EIO; 108 } 109 110 /* check response error code */ 111 response = (struct ec_host_response *)ec_dev->din; 112 ec_msg->result = response->result; 113 114 ret = cros_ec_check_result(ec_dev, ec_msg); 115 if (ret) 116 goto exit; 117 118 if (response->data_len > ec_msg->insize) { 119 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)", 120 response->data_len, ec_msg->insize); 121 ret = -EMSGSIZE; 122 goto exit; 123 } 124 125 /* copy response packet payload and compute checksum */ 126 memcpy(ec_msg->data, ec_dev->din + sizeof(*response), 127 response->data_len); 128 129 sum = 0; 130 for (i = 0; i < sizeof(*response) + response->data_len; i++) 131 sum += ec_dev->din[i]; 132 133 if (sum) { 134 dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n", 135 sum); 136 ret = -EBADMSG; 137 goto exit; 138 } 139 140 ret = response->data_len; 141 exit: 142 if (ec_msg->command == EC_CMD_REBOOT_EC) 143 msleep(EC_REBOOT_DELAY_MS); 144 145 return ret; 146 } 147 148 static void 149 cros_ec_rpmsg_host_event_function(struct work_struct *host_event_work) 150 { 151 struct cros_ec_rpmsg *ec_rpmsg = container_of(host_event_work, 152 struct cros_ec_rpmsg, 153 host_event_work); 154 155 cros_ec_irq_thread(0, dev_get_drvdata(&ec_rpmsg->rpdev->dev)); 156 } 157 158 static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data, 159 int len, void *priv, u32 src) 160 { 161 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev); 162 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv; 163 struct cros_ec_rpmsg_response *resp; 164 165 if (!len) { 166 dev_warn(ec_dev->dev, "rpmsg received empty response"); 167 return -EINVAL; 168 } 169 170 resp = data; 171 len -= offsetof(struct cros_ec_rpmsg_response, data); 172 if (resp->type == HOST_COMMAND_MARK) { 173 if (len > ec_dev->din_size) { 174 dev_warn(ec_dev->dev, 175 "received length %d > din_size %d, truncating", 176 len, ec_dev->din_size); 177 len = ec_dev->din_size; 178 } 179 180 memcpy(ec_dev->din, resp->data, len); 181 complete(&ec_rpmsg->xfer_ack); 182 } else if (resp->type == HOST_EVENT_MARK) { 183 /* 184 * If the host event is sent before cros_ec_register is 185 * finished, queue the host event. 186 */ 187 if (ec_rpmsg->probe_done) 188 schedule_work(&ec_rpmsg->host_event_work); 189 else 190 ec_rpmsg->has_pending_host_event = true; 191 } else { 192 dev_warn(ec_dev->dev, "rpmsg received invalid type = %d", 193 resp->type); 194 return -EINVAL; 195 } 196 197 return 0; 198 } 199 200 static struct rpmsg_endpoint * 201 cros_ec_rpmsg_create_ept(struct rpmsg_device *rpdev) 202 { 203 struct rpmsg_channel_info chinfo = {}; 204 205 strscpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE); 206 chinfo.src = rpdev->src; 207 chinfo.dst = RPMSG_ADDR_ANY; 208 209 return rpmsg_create_ept(rpdev, cros_ec_rpmsg_callback, NULL, chinfo); 210 } 211 212 static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev) 213 { 214 struct device *dev = &rpdev->dev; 215 struct cros_ec_rpmsg *ec_rpmsg; 216 struct cros_ec_device *ec_dev; 217 int ret; 218 219 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); 220 if (!ec_dev) 221 return -ENOMEM; 222 223 ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL); 224 if (!ec_rpmsg) 225 return -ENOMEM; 226 227 ec_dev->dev = dev; 228 ec_dev->priv = ec_rpmsg; 229 ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg; 230 ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg; 231 ec_dev->phys_name = dev_name(&rpdev->dev); 232 ec_dev->din_size = sizeof(struct ec_host_response) + 233 sizeof(struct ec_response_get_protocol_info); 234 ec_dev->dout_size = sizeof(struct ec_host_request); 235 dev_set_drvdata(dev, ec_dev); 236 237 ec_rpmsg->rpdev = rpdev; 238 init_completion(&ec_rpmsg->xfer_ack); 239 INIT_WORK(&ec_rpmsg->host_event_work, 240 cros_ec_rpmsg_host_event_function); 241 242 ec_rpmsg->ept = cros_ec_rpmsg_create_ept(rpdev); 243 if (!ec_rpmsg->ept) 244 return -ENOMEM; 245 246 ret = cros_ec_register(ec_dev); 247 if (ret < 0) { 248 rpmsg_destroy_ept(ec_rpmsg->ept); 249 cancel_work_sync(&ec_rpmsg->host_event_work); 250 return ret; 251 } 252 253 ec_rpmsg->probe_done = true; 254 255 if (ec_rpmsg->has_pending_host_event) 256 schedule_work(&ec_rpmsg->host_event_work); 257 258 return 0; 259 } 260 261 static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev) 262 { 263 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev); 264 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv; 265 266 cros_ec_unregister(ec_dev); 267 rpmsg_destroy_ept(ec_rpmsg->ept); 268 cancel_work_sync(&ec_rpmsg->host_event_work); 269 } 270 271 #ifdef CONFIG_PM_SLEEP 272 static int cros_ec_rpmsg_suspend(struct device *dev) 273 { 274 struct cros_ec_device *ec_dev = dev_get_drvdata(dev); 275 276 return cros_ec_suspend(ec_dev); 277 } 278 279 static int cros_ec_rpmsg_resume(struct device *dev) 280 { 281 struct cros_ec_device *ec_dev = dev_get_drvdata(dev); 282 283 return cros_ec_resume(ec_dev); 284 } 285 #endif 286 287 static SIMPLE_DEV_PM_OPS(cros_ec_rpmsg_pm_ops, cros_ec_rpmsg_suspend, 288 cros_ec_rpmsg_resume); 289 290 static const struct of_device_id cros_ec_rpmsg_of_match[] = { 291 { .compatible = "google,cros-ec-rpmsg", }, 292 { } 293 }; 294 MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match); 295 296 static struct rpmsg_driver cros_ec_driver_rpmsg = { 297 .drv = { 298 .name = "cros-ec-rpmsg", 299 .of_match_table = cros_ec_rpmsg_of_match, 300 .pm = &cros_ec_rpmsg_pm_ops, 301 }, 302 .probe = cros_ec_rpmsg_probe, 303 .remove = cros_ec_rpmsg_remove, 304 }; 305 306 module_rpmsg_driver(cros_ec_driver_rpmsg); 307 308 MODULE_LICENSE("GPL v2"); 309 MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)"); 310