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/mfd/cros_ec.h> 10 #include <linux/mfd/cros_ec_commands.h> 11 #include <linux/of.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 }; 45 46 /** 47 * cros_ec_cmd_xfer_rpmsg - Transfer a message over rpmsg and receive the reply 48 * 49 * @ec_dev: ChromeOS EC device 50 * @ec_msg: Message to transfer 51 * 52 * This is only used for old EC proto version, and is not supported for this 53 * driver. 54 * 55 * Return: -EINVAL 56 */ 57 static int cros_ec_cmd_xfer_rpmsg(struct cros_ec_device *ec_dev, 58 struct cros_ec_command *ec_msg) 59 { 60 return -EINVAL; 61 } 62 63 /** 64 * cros_ec_pkt_xfer_rpmsg - Transfer a packet over rpmsg and receive the reply 65 * 66 * @ec_dev: ChromeOS EC device 67 * @ec_msg: Message to transfer 68 * 69 * Return: number of bytes of the reply on success or negative error code. 70 */ 71 static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev, 72 struct cros_ec_command *ec_msg) 73 { 74 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv; 75 struct rpmsg_device *rpdev = ec_rpmsg->rpdev; 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(rpdev->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 int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev) 200 { 201 struct device *dev = &rpdev->dev; 202 struct cros_ec_rpmsg *ec_rpmsg; 203 struct cros_ec_device *ec_dev; 204 205 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); 206 if (!ec_dev) 207 return -ENOMEM; 208 209 ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL); 210 if (!ec_rpmsg) 211 return -ENOMEM; 212 213 ec_dev->dev = dev; 214 ec_dev->priv = ec_rpmsg; 215 ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg; 216 ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg; 217 ec_dev->phys_name = dev_name(&rpdev->dev); 218 ec_dev->din_size = sizeof(struct ec_host_response) + 219 sizeof(struct ec_response_get_protocol_info); 220 ec_dev->dout_size = sizeof(struct ec_host_request); 221 dev_set_drvdata(dev, ec_dev); 222 223 ec_rpmsg->rpdev = rpdev; 224 init_completion(&ec_rpmsg->xfer_ack); 225 INIT_WORK(&ec_rpmsg->host_event_work, 226 cros_ec_rpmsg_host_event_function); 227 228 return cros_ec_register(ec_dev); 229 } 230 231 static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev) 232 { 233 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev); 234 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv; 235 236 cancel_work_sync(&ec_rpmsg->host_event_work); 237 } 238 239 static const struct of_device_id cros_ec_rpmsg_of_match[] = { 240 { .compatible = "google,cros-ec-rpmsg", }, 241 { } 242 }; 243 MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match); 244 245 static struct rpmsg_driver cros_ec_driver_rpmsg = { 246 .drv = { 247 .name = "cros-ec-rpmsg", 248 .of_match_table = cros_ec_rpmsg_of_match, 249 }, 250 .probe = cros_ec_rpmsg_probe, 251 .remove = cros_ec_rpmsg_remove, 252 .callback = cros_ec_rpmsg_callback, 253 }; 254 255 module_rpmsg_driver(cros_ec_driver_rpmsg); 256 257 MODULE_LICENSE("GPL v2"); 258 MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)"); 259