This driver implements the Greybus logging protocol.
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/greybus/log.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 132 insertions(+)
--- /dev/null
+++ b/drivers/greybus/log.c
@@ -0,0 +1,132 @@
+/*
+ * Greybus driver for the log protocol
+ *
+ * Copyright 2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sizes.h>
+#include <linux/uaccess.h>
+
+#include "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 != (int)(op->request->payload_size - sizeof(*receive))) {
+ dev_err(dev, "log request wrong size %d vs %d\n", len,
+ (int)(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");
