From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752389AbcKRDJI (ORCPT ); Thu, 17 Nov 2016 22:09:08 -0500 Received: from mail-pf0-f173.google.com ([209.85.192.173]:33922 "EHLO mail-pf0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752335AbcKRDJE (ORCPT ); Thu, 17 Nov 2016 22:09:04 -0500 From: Chunyan Zhang To: rostedt@goodmis.org, mathieu.poirier@linaro.org, alexander.shishkin@linux.intel.com, mingo@redhat.com Cc: mike.leach@arm.com, tor@ti.com, philippe.langlais@st.com, nicolas.guion@st.com, felipe.balbi@linux.intel.com, zhang.lyra@gmail.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH V8 2/3] stm class: ftrace: Add ftrace-export-over-stm driver Date: Fri, 18 Nov 2016 11:07:33 +0800 Message-Id: <1479438454-28650-3-git-send-email-zhang.chunyan@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1479438454-28650-1-git-send-email-zhang.chunyan@linaro.org> References: <1479438454-28650-1-git-send-email-zhang.chunyan@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds a driver that models itself as an stm_source called stm_ftrace. Once the stm device and stm_ftrace have been linked via sysfs, the driver registers itself as a trace_export and everything passed to the interface from Ftrace subsystem will end up in the STM trace engine. Signed-off-by: Chunyan Zhang --- drivers/hwtracing/stm/Kconfig | 11 ++++++ drivers/hwtracing/stm/Makefile | 2 + drivers/hwtracing/stm/ftrace.c | 87 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 100 insertions(+) create mode 100644 drivers/hwtracing/stm/ftrace.c diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig index 847a39b..723e2d9 100644 --- a/drivers/hwtracing/stm/Kconfig +++ b/drivers/hwtracing/stm/Kconfig @@ -39,4 +39,15 @@ config STM_SOURCE_HEARTBEAT If you want to send heartbeat messages over STM devices, say Y. +config STM_SOURCE_FTRACE + tristate "Copy the output from kernel Ftrace to STM engine" + depends on FUNCTION_TRACER + help + This option can be used to copy the output from kernel Ftrace + to STM engine. Enabling this option will introduce a slight + timing effect. + + If you want to send kernel Ftrace messages over STM devices, + say Y. + endif diff --git a/drivers/hwtracing/stm/Makefile b/drivers/hwtracing/stm/Makefile index a9ce3d4..3abd84c 100644 --- a/drivers/hwtracing/stm/Makefile +++ b/drivers/hwtracing/stm/Makefile @@ -6,6 +6,8 @@ obj-$(CONFIG_STM_DUMMY) += dummy_stm.o obj-$(CONFIG_STM_SOURCE_CONSOLE) += stm_console.o obj-$(CONFIG_STM_SOURCE_HEARTBEAT) += stm_heartbeat.o +obj-$(CONFIG_STM_SOURCE_FTRACE) += stm_ftrace.o stm_console-y := console.o stm_heartbeat-y := heartbeat.o +stm_ftrace-y := ftrace.o diff --git a/drivers/hwtracing/stm/ftrace.c b/drivers/hwtracing/stm/ftrace.c new file mode 100644 index 0000000..bd126a7 --- /dev/null +++ b/drivers/hwtracing/stm/ftrace.c @@ -0,0 +1,87 @@ +/* + * Simple kernel driver to link kernel Ftrace and an STM device + * Copyright (c) 2016, Linaro Ltd. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * STM Ftrace will be registered as a trace_export. + */ + +#include +#include +#include + +#define STM_FTRACE_NR_CHANNELS 1 +#define STM_FTRACE_CHAN 0 + +static int stm_ftrace_link(struct stm_source_data *data); +static void stm_ftrace_unlink(struct stm_source_data *data); + +static struct stm_ftrace { + struct stm_source_data data; + struct trace_export ftrace; +} stm_ftrace = { + .data = { + .name = "ftrace", + .nr_chans = STM_FTRACE_NR_CHANNELS, + .link = stm_ftrace_link, + .unlink = stm_ftrace_unlink, + }, +}; + +/** + * stm_ftrace_write() - write data to STM via 'stm_ftrace' source + * @buf: buffer containing the data packet + * @len: length of the data packet + */ +static void notrace +stm_ftrace_write(const void *buf, unsigned int len) +{ + stm_source_write(&stm_ftrace.data, STM_FTRACE_CHAN, buf, len); +} + +static int stm_ftrace_link(struct stm_source_data *data) +{ + struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data); + + sf->ftrace.write = stm_ftrace_write; + + return register_ftrace_export(&sf->ftrace); +} + +static void stm_ftrace_unlink(struct stm_source_data *data) +{ + struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data); + + unregister_ftrace_export(&sf->ftrace); +} + +static int __init stm_ftrace_init(void) +{ + int ret; + + ret = stm_source_register_device(NULL, &stm_ftrace.data); + if (ret) + pr_err("Failed to register stm_source - ftrace.\n"); + + return ret; +} + +static void __exit stm_ftrace_exit(void) +{ + stm_source_unregister_device(&stm_ftrace.data); +} + +module_init(stm_ftrace_init); +module_exit(stm_ftrace_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("stm_ftrace driver"); +MODULE_AUTHOR("Chunyan Zhang "); -- 2.7.4