From c0e65d026c297c53eeb5412c31a5410317225945 Mon Sep 17 00:00:00 2001 From: Joel Porquet Date: Fri, 24 Jun 2016 14:41:36 -0700 Subject: [PATCH] greybus: add support for the log protocol Add support for the new Log class/protocol. This protocol allows modules to send their internal logging messages to the AP in order to make module debugging easier. The protocol is, for now, composed a single module-initiated request. This request contains a message and associated length. The message is integrated in the kernel log with dev_dbg(). In order to be displayed with 'dmesg', the following command needs to be entered first: $ echo "file log.c +p" > /sys/kernel/debug/dynamic_debug/control The major portion of this file was initially written by Greg KH. Signed-off-by: Joel Porquet Signed-off-by: Greg Kroah-Hartman --- drivers/staging/greybus/Makefile | 2 + drivers/staging/greybus/greybus_manifest.h | 2 + drivers/staging/greybus/greybus_protocols.h | 14 +++ drivers/staging/greybus/log.c | 132 ++++++++++++++++++++ 4 files changed, 150 insertions(+) create mode 100644 drivers/staging/greybus/log.c diff --git a/drivers/staging/greybus/Makefile b/drivers/staging/greybus/Makefile index 40325b32c5f7..bd9967ca46c6 100644 --- a/drivers/staging/greybus/Makefile +++ b/drivers/staging/greybus/Makefile @@ -18,6 +18,7 @@ gb-gbphy-y := gbphy.o # Prefix all modules with gb- gb-vibrator-y := vibrator.o gb-power-supply-y := power_supply.o +gb-log-y := log.o gb-loopback-y := loopback.o gb-light-y := light.o gb-raw-y := raw.o @@ -46,6 +47,7 @@ obj-m += greybus.o obj-m += gb-gbphy.o obj-m += gb-vibrator.o obj-m += gb-power-supply.o +obj-m += gb-log.o obj-m += gb-loopback.o obj-m += gb-light.o obj-m += gb-hid.o diff --git a/drivers/staging/greybus/greybus_manifest.h b/drivers/staging/greybus/greybus_manifest.h index 28bbadd057d1..2ae39ad92368 100644 --- a/drivers/staging/greybus/greybus_manifest.h +++ b/drivers/staging/greybus/greybus_manifest.h @@ -47,6 +47,7 @@ enum greybus_protocol { GREYBUS_PROTOCOL_CAMERA_DATA = 0x16, GREYBUS_PROTOCOL_FW_DOWNLOAD = 0x17, GREYBUS_PROTOCOL_FW_MANAGEMENT = 0x18, + GREYBUS_PROTOCOL_LOG = 0x1a, /* ... */ GREYBUS_PROTOCOL_RAW = 0xfe, GREYBUS_PROTOCOL_VENDOR = 0xff, @@ -76,6 +77,7 @@ enum greybus_class_type { /* 0x14 is unused */ GREYBUS_CLASS_BOOTROM = 0x15, GREYBUS_CLASS_FW_MANAGEMENT = 0x16, + GREYBUS_CLASS_LOG = 0x17, /* ... */ GREYBUS_CLASS_RAW = 0xfe, GREYBUS_CLASS_VENDOR = 0xff, diff --git a/drivers/staging/greybus/greybus_protocols.h b/drivers/staging/greybus/greybus_protocols.h index 63dd2041fdeb..203bc46151e7 100644 --- a/drivers/staging/greybus/greybus_protocols.h +++ b/drivers/staging/greybus/greybus_protocols.h @@ -2136,5 +2136,19 @@ struct gb_audio_send_data_request { __u8 data[0]; } __packed; + +/* Log */ + +/* operations */ +#define GB_LOG_TYPE_SEND_LOG 0x02 + +/* length */ +#define GB_LOG_MAX_LEN 1024 + +struct gb_log_send_log_request { + __le16 len; + __u8 msg[0]; +} __packed; + #endif /* __GREYBUS_PROTOCOLS_H */ diff --git a/drivers/staging/greybus/log.c b/drivers/staging/greybus/log.c new file mode 100644 index 000000000000..70dd9e5a1cf2 --- /dev/null +++ b/drivers/staging/greybus/log.c @@ -0,0 +1,132 @@ +/* + * Greybus driver for the log protocol + * + * Copyright 2016 Google Inc. + * + * Released under the GPLv2 only. + */ +#include +#include +#include +#include +#include + +#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");