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