1262e1f6eSChunyan Zhang /* 2262e1f6eSChunyan Zhang * Simple kernel driver to link kernel Ftrace and an STM device 3262e1f6eSChunyan Zhang * Copyright (c) 2016, Linaro Ltd. 4262e1f6eSChunyan Zhang * 5262e1f6eSChunyan Zhang * This program is free software; you can redistribute it and/or modify it 6262e1f6eSChunyan Zhang * under the terms and conditions of the GNU General Public License, 7262e1f6eSChunyan Zhang * version 2, as published by the Free Software Foundation. 8262e1f6eSChunyan Zhang * 9262e1f6eSChunyan Zhang * This program is distributed in the hope it will be useful, but WITHOUT 10262e1f6eSChunyan Zhang * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11262e1f6eSChunyan Zhang * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 12262e1f6eSChunyan Zhang * more details. 13262e1f6eSChunyan Zhang * 14262e1f6eSChunyan Zhang * STM Ftrace will be registered as a trace_export. 15262e1f6eSChunyan Zhang */ 16262e1f6eSChunyan Zhang 17262e1f6eSChunyan Zhang #include <linux/module.h> 18262e1f6eSChunyan Zhang #include <linux/stm.h> 19262e1f6eSChunyan Zhang #include <linux/trace.h> 20262e1f6eSChunyan Zhang 21262e1f6eSChunyan Zhang #define STM_FTRACE_NR_CHANNELS 1 22262e1f6eSChunyan Zhang #define STM_FTRACE_CHAN 0 23262e1f6eSChunyan Zhang 24262e1f6eSChunyan Zhang static int stm_ftrace_link(struct stm_source_data *data); 25262e1f6eSChunyan Zhang static void stm_ftrace_unlink(struct stm_source_data *data); 26262e1f6eSChunyan Zhang 27262e1f6eSChunyan Zhang static struct stm_ftrace { 28262e1f6eSChunyan Zhang struct stm_source_data data; 29262e1f6eSChunyan Zhang struct trace_export ftrace; 30262e1f6eSChunyan Zhang } stm_ftrace = { 31262e1f6eSChunyan Zhang .data = { 32262e1f6eSChunyan Zhang .name = "ftrace", 33262e1f6eSChunyan Zhang .nr_chans = STM_FTRACE_NR_CHANNELS, 34262e1f6eSChunyan Zhang .link = stm_ftrace_link, 35262e1f6eSChunyan Zhang .unlink = stm_ftrace_unlink, 36262e1f6eSChunyan Zhang }, 37262e1f6eSChunyan Zhang }; 38262e1f6eSChunyan Zhang 39262e1f6eSChunyan Zhang /** 40262e1f6eSChunyan Zhang * stm_ftrace_write() - write data to STM via 'stm_ftrace' source 41262e1f6eSChunyan Zhang * @buf: buffer containing the data packet 42262e1f6eSChunyan Zhang * @len: length of the data packet 43262e1f6eSChunyan Zhang */ 44262e1f6eSChunyan Zhang static void notrace 45*a773d419SFelipe Balbi stm_ftrace_write(struct trace_export *export, const void *buf, unsigned int len) 46262e1f6eSChunyan Zhang { 47*a773d419SFelipe Balbi struct stm_ftrace *stm = container_of(export, struct stm_ftrace, ftrace); 48*a773d419SFelipe Balbi 49*a773d419SFelipe Balbi stm_source_write(&stm->data, STM_FTRACE_CHAN, buf, len); 50262e1f6eSChunyan Zhang } 51262e1f6eSChunyan Zhang 52262e1f6eSChunyan Zhang static int stm_ftrace_link(struct stm_source_data *data) 53262e1f6eSChunyan Zhang { 54262e1f6eSChunyan Zhang struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data); 55262e1f6eSChunyan Zhang 56262e1f6eSChunyan Zhang sf->ftrace.write = stm_ftrace_write; 57262e1f6eSChunyan Zhang 58262e1f6eSChunyan Zhang return register_ftrace_export(&sf->ftrace); 59262e1f6eSChunyan Zhang } 60262e1f6eSChunyan Zhang 61262e1f6eSChunyan Zhang static void stm_ftrace_unlink(struct stm_source_data *data) 62262e1f6eSChunyan Zhang { 63262e1f6eSChunyan Zhang struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data); 64262e1f6eSChunyan Zhang 65262e1f6eSChunyan Zhang unregister_ftrace_export(&sf->ftrace); 66262e1f6eSChunyan Zhang } 67262e1f6eSChunyan Zhang 68262e1f6eSChunyan Zhang static int __init stm_ftrace_init(void) 69262e1f6eSChunyan Zhang { 70262e1f6eSChunyan Zhang int ret; 71262e1f6eSChunyan Zhang 72262e1f6eSChunyan Zhang ret = stm_source_register_device(NULL, &stm_ftrace.data); 73262e1f6eSChunyan Zhang if (ret) 74262e1f6eSChunyan Zhang pr_err("Failed to register stm_source - ftrace.\n"); 75262e1f6eSChunyan Zhang 76262e1f6eSChunyan Zhang return ret; 77262e1f6eSChunyan Zhang } 78262e1f6eSChunyan Zhang 79262e1f6eSChunyan Zhang static void __exit stm_ftrace_exit(void) 80262e1f6eSChunyan Zhang { 81262e1f6eSChunyan Zhang stm_source_unregister_device(&stm_ftrace.data); 82262e1f6eSChunyan Zhang } 83262e1f6eSChunyan Zhang 84262e1f6eSChunyan Zhang module_init(stm_ftrace_init); 85262e1f6eSChunyan Zhang module_exit(stm_ftrace_exit); 86262e1f6eSChunyan Zhang 87262e1f6eSChunyan Zhang MODULE_LICENSE("GPL v2"); 88262e1f6eSChunyan Zhang MODULE_DESCRIPTION("stm_ftrace driver"); 89262e1f6eSChunyan Zhang MODULE_AUTHOR("Chunyan Zhang <zhang.chunyan@linaro.org>"); 90