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); 152 153 cros_ec_irq_thread(0, dev_get_drvdata(&ec_rpmsg->rpdev->dev)); 154 } 155 156 static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data, 157 int len, void *priv, u32 src) 158 { 159 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev); 160 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv; 161 struct cros_ec_rpmsg_response *resp; 162 163 if (!len) { 164 dev_warn(ec_dev->dev, "rpmsg received empty response"); 165 return -EINVAL; 166 } 167 168 resp = data; 169 len -= offsetof(struct cros_ec_rpmsg_response, data); 170 if (resp->type == HOST_COMMAND_MARK) { 171 if (len > ec_dev->din_size) { 172 dev_warn(ec_dev->dev, 173 "received length %d > din_size %d, truncating", 174 len, ec_dev->din_size); 175 len = ec_dev->din_size; 176 } 177 178 memcpy(ec_dev->din, resp->data, len); 179 complete(&ec_rpmsg->xfer_ack); 180 } else if (resp->type == HOST_EVENT_MARK) { 181 /* 182 * If the host event is sent before cros_ec_register is 183 * finished, queue the host event. 184 */ 185 if (ec_rpmsg->probe_done) 186 schedule_work(&ec_rpmsg->host_event_work); 187 else 188 ec_rpmsg->has_pending_host_event = true; 189 } else { 190 dev_warn(ec_dev->dev, "rpmsg received invalid type = %d", 191 resp->type); 192 return -EINVAL; 193 } 194 195 return 0; 196 } 197 198 static struct rpmsg_endpoint * 199 cros_ec_rpmsg_create_ept(struct rpmsg_device *rpdev) 200 { 201 struct rpmsg_channel_info chinfo = {}; 202 203 strscpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE); 204 chinfo.src = rpdev->src; 205 chinfo.dst = RPMSG_ADDR_ANY; 206 207 return rpmsg_create_ept(rpdev, cros_ec_rpmsg_callback, NULL, chinfo); 208 } 209 210 static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev) 211 { 212 struct device *dev = &rpdev->dev; 213 struct cros_ec_rpmsg *ec_rpmsg; 214 struct cros_ec_device *ec_dev; 215 int ret; 216 217 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); 218 if (!ec_dev) 219 return -ENOMEM; 220 221 ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL); 222 if (!ec_rpmsg) 223 return -ENOMEM; 224 225 ec_dev->dev = dev; 226 ec_dev->priv = ec_rpmsg; 227 ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg; 228 ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg; 229 ec_dev->phys_name = dev_name(&rpdev->dev); 230 ec_dev->din_size = sizeof(struct ec_host_response) + 231 sizeof(struct ec_response_get_protocol_info); 232 ec_dev->dout_size = sizeof(struct ec_host_request); 233 dev_set_drvdata(dev, ec_dev); 234 235 ec_rpmsg->rpdev = rpdev; 236 init_completion(&ec_rpmsg->xfer_ack); 237 INIT_WORK(&ec_rpmsg->host_event_work, 238 cros_ec_rpmsg_host_event_function); 239 240 ec_rpmsg->ept = cros_ec_rpmsg_create_ept(rpdev); 241 if (!ec_rpmsg->ept) 242 return -ENOMEM; 243 244 ret = cros_ec_register(ec_dev); 245 if (ret < 0) { 246 rpmsg_destroy_ept(ec_rpmsg->ept); 247 cancel_work_sync(&ec_rpmsg->host_event_work); 248 return ret; 249 } 250 251 ec_rpmsg->probe_done = true; 252 253 if (ec_rpmsg->has_pending_host_event) 254 schedule_work(&ec_rpmsg->host_event_work); 255 256 return 0; 257 } 258 259 static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev) 260 { 261 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev); 262 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv; 263 264 cros_ec_unregister(ec_dev); 265 rpmsg_destroy_ept(ec_rpmsg->ept); 266 cancel_work_sync(&ec_rpmsg->host_event_work); 267 } 268 269 #ifdef CONFIG_PM_SLEEP 270 static int cros_ec_rpmsg_suspend(struct device *dev) 271 { 272 struct cros_ec_device *ec_dev = dev_get_drvdata(dev); 273 274 return cros_ec_suspend(ec_dev); 275 } 276 277 static int cros_ec_rpmsg_resume(struct device *dev) 278 { 279 struct cros_ec_device *ec_dev = dev_get_drvdata(dev); 280 281 return cros_ec_resume(ec_dev); 282 } 283 #endif 284 285 static SIMPLE_DEV_PM_OPS(cros_ec_rpmsg_pm_ops, cros_ec_rpmsg_suspend, 286 cros_ec_rpmsg_resume); 287 288 static const struct of_device_id cros_ec_rpmsg_of_match[] = { 289 { .compatible = "google,cros-ec-rpmsg", }, 290 { } 291 }; 292 MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match); 293 294 static struct rpmsg_driver cros_ec_driver_rpmsg = { 295 .drv = { 296 .name = "cros-ec-rpmsg", 297 .of_match_table = cros_ec_rpmsg_of_match, 298 .pm = &cros_ec_rpmsg_pm_ops, 299 }, 300 .probe = cros_ec_rpmsg_probe, 301 .remove = cros_ec_rpmsg_remove, 302 }; 303 304 module_rpmsg_driver(cros_ec_driver_rpmsg); 305 306 MODULE_LICENSE("GPL v2"); 307 MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)"); 308