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