drivers/platform/chrome/cros_ec_rpmsg.c

   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         struct cros_ec_device *ec_dev = dev_get_drvdata(&ec_rpmsg->rpdev->dev);
 153         bool ec_has_more_events;
 154
 155         do {
 156                 ec_has_more_events = cros_ec_handle_event(ec_dev);
 157         } while (ec_has_more_events);
 158 }
 159
 160 static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
 161                                   int len, void *priv, u32 src)
 162 {
 163         struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
 164         struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
 165         struct cros_ec_rpmsg_response *resp;
 166
 167         if (!len) {
 168                 dev_warn(ec_dev->dev, "rpmsg received empty response");
 169                 return -EINVAL;
 170         }
 171
 172         resp = data;
 173         len -= offsetof(struct cros_ec_rpmsg_response, data);
 174         if (resp->type == HOST_COMMAND_MARK) {
 175                 if (len > ec_dev->din_size) {
 176                         dev_warn(ec_dev->dev,
 177                                  "received length %d > din_size %d, truncating",
 178                                  len, ec_dev->din_size);
 179                         len = ec_dev->din_size;
 180                 }
 181
 182                 memcpy(ec_dev->din, resp->data, len);
 183                 complete(&ec_rpmsg->xfer_ack);
 184         } else if (resp->type == HOST_EVENT_MARK) {
 185                 /*
 186                  * If the host event is sent before cros_ec_register is
 187                  * finished, queue the host event.
 188                  */
 189                 if (ec_rpmsg->probe_done)
 190                         schedule_work(&ec_rpmsg->host_event_work);
 191                 else
 192                         ec_rpmsg->has_pending_host_event = true;
 193         } else {
 194                 dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
 195                          resp->type);
 196                 return -EINVAL;
 197         }
 198
 199         return 0;
 200 }
 201
 202 static struct rpmsg_endpoint *
 203 cros_ec_rpmsg_create_ept(struct rpmsg_device *rpdev)
 204 {
 205         struct rpmsg_channel_info chinfo = {};
 206
 207         strscpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
 208         chinfo.src = rpdev->src;
 209         chinfo.dst = RPMSG_ADDR_ANY;
 210
 211         return rpmsg_create_ept(rpdev, cros_ec_rpmsg_callback, NULL, chinfo);
 212 }
 213
 214 static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
 215 {
 216         struct device *dev = &rpdev->dev;
 217         struct cros_ec_rpmsg *ec_rpmsg;
 218         struct cros_ec_device *ec_dev;
 219         int ret;
 220
 221         ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
 222         if (!ec_dev)
 223                 return -ENOMEM;
 224
 225         ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
 226         if (!ec_rpmsg)
 227                 return -ENOMEM;
 228
 229         ec_dev->dev = dev;
 230         ec_dev->priv = ec_rpmsg;
 231         ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
 232         ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
 233         ec_dev->phys_name = dev_name(&rpdev->dev);
 234         ec_dev->din_size = sizeof(struct ec_host_response) +
 235                            sizeof(struct ec_response_get_protocol_info);
 236         ec_dev->dout_size = sizeof(struct ec_host_request);
 237         dev_set_drvdata(dev, ec_dev);
 238
 239         ec_rpmsg->rpdev = rpdev;
 240         init_completion(&ec_rpmsg->xfer_ack);
 241         INIT_WORK(&ec_rpmsg->host_event_work,
 242                   cros_ec_rpmsg_host_event_function);
 243
 244         ec_rpmsg->ept = cros_ec_rpmsg_create_ept(rpdev);
 245         if (!ec_rpmsg->ept)
 246                 return -ENOMEM;
 247
 248         ret = cros_ec_register(ec_dev);
 249         if (ret < 0) {
 250                 rpmsg_destroy_ept(ec_rpmsg->ept);
 251                 cancel_work_sync(&ec_rpmsg->host_event_work);
 252                 return ret;
 253         }
 254
 255         ec_rpmsg->probe_done = true;
 256
 257         if (ec_rpmsg->has_pending_host_event)
 258                 schedule_work(&ec_rpmsg->host_event_work);
 259
 260         return 0;
 261 }
 262
 263 static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
 264 {
 265         struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
 266         struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
 267
 268         cros_ec_unregister(ec_dev);
 269         rpmsg_destroy_ept(ec_rpmsg->ept);
 270         cancel_work_sync(&ec_rpmsg->host_event_work);
 271 }
 272
 273 #ifdef CONFIG_PM_SLEEP
 274 static int cros_ec_rpmsg_suspend(struct device *dev)
 275 {
 276         struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
 277
 278         return cros_ec_suspend(ec_dev);
 279 }
 280
 281 static int cros_ec_rpmsg_resume(struct device *dev)
 282 {
 283         struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
 284
 285         return cros_ec_resume(ec_dev);
 286 }
 287 #endif
 288
 289 static SIMPLE_DEV_PM_OPS(cros_ec_rpmsg_pm_ops, cros_ec_rpmsg_suspend,
 290                          cros_ec_rpmsg_resume);
 291
 292 static const struct of_device_id cros_ec_rpmsg_of_match[] = {
 293         { .compatible = "google,cros-ec-rpmsg", },
 294         { }
 295 };
 296 MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
 297
 298 static struct rpmsg_driver cros_ec_driver_rpmsg = {
 299         .drv = {
 300                 .name   = "cros-ec-rpmsg",
 301                 .of_match_table = cros_ec_rpmsg_of_match,
 302                 .pm     = &cros_ec_rpmsg_pm_ops,
 303         },
 304         .probe          = cros_ec_rpmsg_probe,
 305         .remove         = cros_ec_rpmsg_remove,
 306 };
 307
 308 module_rpmsg_driver(cros_ec_driver_rpmsg);
 309
 310 MODULE_LICENSE("GPL v2");
 311 MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");