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  */
  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         bool has_pending_host_event;
  48         bool probe_done;
  49 };
  50
  51 /**
  52  * cros_ec_cmd_xfer_rpmsg - Transfer a message over rpmsg and receive the reply
  53  *
  54  * @ec_dev: ChromeOS EC device
  55  * @ec_msg: Message to transfer
  56  *
  57  * This is only used for old EC proto version, and is not supported for this
  58  * driver.
  59  *
  60  * Return: -EINVAL
  61  */
  62 static int cros_ec_cmd_xfer_rpmsg(struct cros_ec_device *ec_dev,
  63                                   struct cros_ec_command *ec_msg)
  64 {
  65         return -EINVAL;
  66 }
  67
  68 /**
  69  * cros_ec_pkt_xfer_rpmsg - Transfer a packet over rpmsg and receive the reply
  70  *
  71  * @ec_dev: ChromeOS EC device
  72  * @ec_msg: Message to transfer
  73  *
  74  * Return: number of bytes of the reply on success or negative error code.
  75  */
  76 static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev,
  77                                   struct cros_ec_command *ec_msg)
  78 {
  79         struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
  80         struct ec_host_response *response;
  81         unsigned long timeout;
  82         int len;
  83         int ret;
  84         u8 sum;
  85         int i;
  86
  87         ec_msg->result = 0;
  88         len = cros_ec_prepare_tx(ec_dev, ec_msg);
  89         dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
  90
  91         reinit_completion(&ec_rpmsg->xfer_ack);
  92         ret = rpmsg_send(ec_rpmsg->ept, ec_dev->dout, len);
  93         if (ret) {
  94                 dev_err(ec_dev->dev, "rpmsg send failed\n");
  95                 return ret;
  96         }
  97
  98         timeout = msecs_to_jiffies(EC_MSG_TIMEOUT_MS);
  99         ret = wait_for_completion_timeout(&ec_rpmsg->xfer_ack, timeout);
 100         if (!ret) {
 101                 dev_err(ec_dev->dev, "rpmsg send timeout\n");
 102                 return -EIO;
 103         }
 104
 105         /* check response error code */
 106         response = (struct ec_host_response *)ec_dev->din;
 107         ec_msg->result = response->result;
 108
 109         ret = cros_ec_check_result(ec_dev, ec_msg);
 110         if (ret)
 111                 goto exit;
 112
 113         if (response->data_len > ec_msg->insize) {
 114                 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
 115                         response->data_len, ec_msg->insize);
 116                 ret = -EMSGSIZE;
 117                 goto exit;
 118         }
 119
 120         /* copy response packet payload and compute checksum */
 121         memcpy(ec_msg->data, ec_dev->din + sizeof(*response),
 122                response->data_len);
 123
 124         sum = 0;
 125         for (i = 0; i < sizeof(*response) + response->data_len; i++)
 126                 sum += ec_dev->din[i];
 127
 128         if (sum) {
 129                 dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n",
 130                         sum);
 131                 ret = -EBADMSG;
 132                 goto exit;
 133         }
 134
 135         ret = response->data_len;
 136 exit:
 137         if (ec_msg->command == EC_CMD_REBOOT_EC)
 138                 msleep(EC_REBOOT_DELAY_MS);
 139
 140         return ret;
 141 }
 142
 143 static void
 144 cros_ec_rpmsg_host_event_function(struct work_struct *host_event_work)
 145 {
 146         struct cros_ec_rpmsg *ec_rpmsg = container_of(host_event_work,
 147                                                       struct cros_ec_rpmsg,
 148                                                       host_event_work);
 149         struct cros_ec_device *ec_dev = dev_get_drvdata(&ec_rpmsg->rpdev->dev);
 150         bool ec_has_more_events;
 151
 152         do {
 153                 ec_has_more_events = cros_ec_handle_event(ec_dev);
 154         } while (ec_has_more_events);
 155 }
 156
 157 static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
 158                                   int len, void *priv, u32 src)
 159 {
 160         struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
 161         struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
 162         struct cros_ec_rpmsg_response *resp;
 163
 164         if (!len) {
 165                 dev_warn(ec_dev->dev, "rpmsg received empty response");
 166                 return -EINVAL;
 167         }
 168
 169         resp = data;
 170         len -= offsetof(struct cros_ec_rpmsg_response, data);
 171         if (resp->type == HOST_COMMAND_MARK) {
 172                 if (len > ec_dev->din_size) {
 173                         dev_warn(ec_dev->dev,
 174                                  "received length %d > din_size %d, truncating",
 175                                  len, ec_dev->din_size);
 176                         len = ec_dev->din_size;
 177                 }
 178
 179                 memcpy(ec_dev->din, resp->data, len);
 180                 complete(&ec_rpmsg->xfer_ack);
 181         } else if (resp->type == HOST_EVENT_MARK) {
 182                 /*
 183                  * If the host event is sent before cros_ec_register is
 184                  * finished, queue the host event.
 185                  */
 186                 if (ec_rpmsg->probe_done)
 187                         schedule_work(&ec_rpmsg->host_event_work);
 188                 else
 189                         ec_rpmsg->has_pending_host_event = true;
 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 struct rpmsg_endpoint *
 200 cros_ec_rpmsg_create_ept(struct rpmsg_device *rpdev)
 201 {
 202         struct rpmsg_channel_info chinfo = {};
 203
 204         strscpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
 205         chinfo.src = rpdev->src;
 206         chinfo.dst = RPMSG_ADDR_ANY;
 207
 208         return rpmsg_create_ept(rpdev, cros_ec_rpmsg_callback, NULL, chinfo);
 209 }
 210
 211 static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
 212 {
 213         struct device *dev = &rpdev->dev;
 214         struct cros_ec_rpmsg *ec_rpmsg;
 215         struct cros_ec_device *ec_dev;
 216         int ret;
 217
 218         ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
 219         if (!ec_dev)
 220                 return -ENOMEM;
 221
 222         ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
 223         if (!ec_rpmsg)
 224                 return -ENOMEM;
 225
 226         ec_dev->dev = dev;
 227         ec_dev->priv = ec_rpmsg;
 228         ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
 229         ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
 230         ec_dev->phys_name = dev_name(&rpdev->dev);
 231         ec_dev->din_size = sizeof(struct ec_host_response) +
 232                            sizeof(struct ec_response_get_protocol_info);
 233         ec_dev->dout_size = sizeof(struct ec_host_request);
 234         dev_set_drvdata(dev, ec_dev);
 235
 236         ec_rpmsg->rpdev = rpdev;
 237         init_completion(&ec_rpmsg->xfer_ack);
 238         INIT_WORK(&ec_rpmsg->host_event_work,
 239                   cros_ec_rpmsg_host_event_function);
 240
 241         ec_rpmsg->ept = cros_ec_rpmsg_create_ept(rpdev);
 242         if (!ec_rpmsg->ept)
 243                 return -ENOMEM;
 244
 245         ret = cros_ec_register(ec_dev);
 246         if (ret < 0) {
 247                 rpmsg_destroy_ept(ec_rpmsg->ept);
 248                 cancel_work_sync(&ec_rpmsg->host_event_work);
 249                 return ret;
 250         }
 251
 252         ec_rpmsg->probe_done = true;
 253
 254         if (ec_rpmsg->has_pending_host_event)
 255                 schedule_work(&ec_rpmsg->host_event_work);
 256
 257         return 0;
 258 }
 259
 260 static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
 261 {
 262         struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
 263         struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
 264
 265         cros_ec_unregister(ec_dev);
 266         rpmsg_destroy_ept(ec_rpmsg->ept);
 267         cancel_work_sync(&ec_rpmsg->host_event_work);
 268 }
 269
 270 #ifdef CONFIG_PM_SLEEP
 271 static int cros_ec_rpmsg_suspend(struct device *dev)
 272 {
 273         struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
 274
 275         return cros_ec_suspend(ec_dev);
 276 }
 277
 278 static int cros_ec_rpmsg_resume(struct device *dev)
 279 {
 280         struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
 281
 282         return cros_ec_resume(ec_dev);
 283 }
 284 #endif
 285
 286 static SIMPLE_DEV_PM_OPS(cros_ec_rpmsg_pm_ops, cros_ec_rpmsg_suspend,
 287                          cros_ec_rpmsg_resume);
 288
 289 static const struct of_device_id cros_ec_rpmsg_of_match[] = {
 290         { .compatible = "google,cros-ec-rpmsg", },
 291         { }
 292 };
 293 MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
 294
 295 static struct rpmsg_driver cros_ec_driver_rpmsg = {
 296         .drv = {
 297                 .name   = "cros-ec-rpmsg",
 298                 .of_match_table = cros_ec_rpmsg_of_match,
 299                 .pm     = &cros_ec_rpmsg_pm_ops,
 300         },
 301         .probe          = cros_ec_rpmsg_probe,
 302         .remove         = cros_ec_rpmsg_remove,
 303 };
 304
 305 module_rpmsg_driver(cros_ec_driver_rpmsg);
 306
 307 MODULE_LICENSE("GPL v2");
 308 MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");