1*262e1f6eSChunyan Zhang /* 2*262e1f6eSChunyan Zhang * Simple kernel driver to link kernel Ftrace and an STM device 3*262e1f6eSChunyan Zhang * Copyright (c) 2016, Linaro Ltd. 4*262e1f6eSChunyan Zhang * 5*262e1f6eSChunyan Zhang * This program is free software; you can redistribute it and/or modify it 6*262e1f6eSChunyan Zhang * under the terms and conditions of the GNU General Public License, 7*262e1f6eSChunyan Zhang * version 2, as published by the Free Software Foundation. 8*262e1f6eSChunyan Zhang * 9*262e1f6eSChunyan Zhang * This program is distributed in the hope it will be useful, but WITHOUT 10*262e1f6eSChunyan Zhang * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11*262e1f6eSChunyan Zhang * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 12*262e1f6eSChunyan Zhang * more details. 13*262e1f6eSChunyan Zhang * 14*262e1f6eSChunyan Zhang * STM Ftrace will be registered as a trace_export. 15*262e1f6eSChunyan Zhang */ 16*262e1f6eSChunyan Zhang 17*262e1f6eSChunyan Zhang #include <linux/module.h> 18*262e1f6eSChunyan Zhang #include <linux/stm.h> 19*262e1f6eSChunyan Zhang #include <linux/trace.h> 20*262e1f6eSChunyan Zhang 21*262e1f6eSChunyan Zhang #define STM_FTRACE_NR_CHANNELS 1 22*262e1f6eSChunyan Zhang #define STM_FTRACE_CHAN 0 23*262e1f6eSChunyan Zhang 24*262e1f6eSChunyan Zhang static int stm_ftrace_link(struct stm_source_data *data); 25*262e1f6eSChunyan Zhang static void stm_ftrace_unlink(struct stm_source_data *data); 26*262e1f6eSChunyan Zhang 27*262e1f6eSChunyan Zhang static struct stm_ftrace { 28*262e1f6eSChunyan Zhang struct stm_source_data data; 29*262e1f6eSChunyan Zhang struct trace_export ftrace; 30*262e1f6eSChunyan Zhang } stm_ftrace = { 31*262e1f6eSChunyan Zhang .data = { 32*262e1f6eSChunyan Zhang .name = "ftrace", 33*262e1f6eSChunyan Zhang .nr_chans = STM_FTRACE_NR_CHANNELS, 34*262e1f6eSChunyan Zhang .link = stm_ftrace_link, 35*262e1f6eSChunyan Zhang .unlink = stm_ftrace_unlink, 36*262e1f6eSChunyan Zhang }, 37*262e1f6eSChunyan Zhang }; 38*262e1f6eSChunyan Zhang 39*262e1f6eSChunyan Zhang /** 40*262e1f6eSChunyan Zhang * stm_ftrace_write() - write data to STM via 'stm_ftrace' source 41*262e1f6eSChunyan Zhang * @buf: buffer containing the data packet 42*262e1f6eSChunyan Zhang * @len: length of the data packet 43*262e1f6eSChunyan Zhang */ 44*262e1f6eSChunyan Zhang static void notrace 45*262e1f6eSChunyan Zhang stm_ftrace_write(const void *buf, unsigned int len) 46*262e1f6eSChunyan Zhang { 47*262e1f6eSChunyan Zhang stm_source_write(&stm_ftrace.data, STM_FTRACE_CHAN, buf, len); 48*262e1f6eSChunyan Zhang } 49*262e1f6eSChunyan Zhang 50*262e1f6eSChunyan Zhang static int stm_ftrace_link(struct stm_source_data *data) 51*262e1f6eSChunyan Zhang { 52*262e1f6eSChunyan Zhang struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data); 53*262e1f6eSChunyan Zhang 54*262e1f6eSChunyan Zhang sf->ftrace.write = stm_ftrace_write; 55*262e1f6eSChunyan Zhang 56*262e1f6eSChunyan Zhang return register_ftrace_export(&sf->ftrace); 57*262e1f6eSChunyan Zhang } 58*262e1f6eSChunyan Zhang 59*262e1f6eSChunyan Zhang static void stm_ftrace_unlink(struct stm_source_data *data) 60*262e1f6eSChunyan Zhang { 61*262e1f6eSChunyan Zhang struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data); 62*262e1f6eSChunyan Zhang 63*262e1f6eSChunyan Zhang unregister_ftrace_export(&sf->ftrace); 64*262e1f6eSChunyan Zhang } 65*262e1f6eSChunyan Zhang 66*262e1f6eSChunyan Zhang static int __init stm_ftrace_init(void) 67*262e1f6eSChunyan Zhang { 68*262e1f6eSChunyan Zhang int ret; 69*262e1f6eSChunyan Zhang 70*262e1f6eSChunyan Zhang ret = stm_source_register_device(NULL, &stm_ftrace.data); 71*262e1f6eSChunyan Zhang if (ret) 72*262e1f6eSChunyan Zhang pr_err("Failed to register stm_source - ftrace.\n"); 73*262e1f6eSChunyan Zhang 74*262e1f6eSChunyan Zhang return ret; 75*262e1f6eSChunyan Zhang } 76*262e1f6eSChunyan Zhang 77*262e1f6eSChunyan Zhang static void __exit stm_ftrace_exit(void) 78*262e1f6eSChunyan Zhang { 79*262e1f6eSChunyan Zhang stm_source_unregister_device(&stm_ftrace.data); 80*262e1f6eSChunyan Zhang } 81*262e1f6eSChunyan Zhang 82*262e1f6eSChunyan Zhang module_init(stm_ftrace_init); 83*262e1f6eSChunyan Zhang module_exit(stm_ftrace_exit); 84*262e1f6eSChunyan Zhang 85*262e1f6eSChunyan Zhang MODULE_LICENSE("GPL v2"); 86*262e1f6eSChunyan Zhang MODULE_DESCRIPTION("stm_ftrace driver"); 87*262e1f6eSChunyan Zhang MODULE_AUTHOR("Chunyan Zhang <zhang.chunyan@linaro.org>"); 88