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// SPDX-License-Identifier: GPL-2.0
/*
* Greybus driver for the log protocol
*
* Copyright 2016 Google Inc.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sizes.h>
#include <linux/uaccess.h>
#include <linux/greybus.h>
struct gb_log {
struct gb_connection *connection;
};
static int gb_log_request_handler(struct gb_operation *op)
{
struct gb_connection *connection = op->connection;
struct device *dev = &connection->bundle->dev;
struct gb_log_send_log_request *receive;
u16 len;
if (op->type != GB_LOG_TYPE_SEND_LOG) {
dev_err(dev, "unknown request type 0x%02x\n", op->type);
return -EINVAL;
}
/* Verify size of payload */
if (op->request->payload_size < sizeof(*receive)) {
dev_err(dev, "log request too small (%zu < %zu)\n",
op->request->payload_size, sizeof(*receive));
return -EINVAL;
}
receive = op->request->payload;
len = le16_to_cpu(receive->len);
if (len != (op->request->payload_size - sizeof(*receive))) {
dev_err(dev, "log request wrong size %d vs %zu\n", len,
(op->request->payload_size - sizeof(*receive)));
return -EINVAL;
}
if (len == 0) {
dev_err(dev, "log request of 0 bytes?\n");
return -EINVAL;
}
if (len > GB_LOG_MAX_LEN) {
dev_err(dev, "log request too big: %d\n", len);
return -EINVAL;
}
/* Ensure the buffer is 0 terminated */
receive->msg[len - 1] = '\0';
/*
* Print with dev_dbg() so that it can be easily turned off using
* dynamic debugging (and prevent any DoS)
*/
dev_dbg(dev, "%s", receive->msg);
return 0;
}
static int gb_log_probe(struct gb_bundle *bundle,
const struct greybus_bundle_id *id)
{
struct greybus_descriptor_cport *cport_desc;
struct gb_connection *connection;
struct gb_log *log;
int retval;
if (bundle->num_cports != 1)
return -ENODEV;
cport_desc = &bundle->cport_desc[0];
if (cport_desc->protocol_id != GREYBUS_PROTOCOL_LOG)
return -ENODEV;
log = kzalloc(sizeof(*log), GFP_KERNEL);
if (!log)
return -ENOMEM;
connection = gb_connection_create(bundle, le16_to_cpu(cport_desc->id),
gb_log_request_handler);
if (IS_ERR(connection)) {
retval = PTR_ERR(connection);
goto error_free;
}
log->connection = connection;
greybus_set_drvdata(bundle, log);
retval = gb_connection_enable(connection);
if (retval)
goto error_connection_destroy;
return 0;
error_connection_destroy:
gb_connection_destroy(connection);
error_free:
kfree(log);
return retval;
}
static void gb_log_disconnect(struct gb_bundle *bundle)
{
struct gb_log *log = greybus_get_drvdata(bundle);
struct gb_connection *connection = log->connection;
gb_connection_disable(connection);
gb_connection_destroy(connection);
kfree(log);
}
static const struct greybus_bundle_id gb_log_id_table[] = {
{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_LOG) },
{ }
};
MODULE_DEVICE_TABLE(greybus, gb_log_id_table);
static struct greybus_driver gb_log_driver = {
.name = "log",
.probe = gb_log_probe,
.disconnect = gb_log_disconnect,
.id_table = gb_log_id_table,
};
module_greybus_driver(gb_log_driver);
MODULE_LICENSE("GPL v2");
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