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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - drivers/hwtracing/stm/ftrace.c
2 * Simple kernel driver to link kernel Ftrace and an STM device
3 * Copyright (c) 2016, Linaro Ltd.
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms and conditions of the GNU General Public License,
7 * version 2, as published by the Free Software Foundation.
9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * STM Ftrace will be registered as a trace_export.
17 #include <linux/module.h>
18 #include <linux/stm.h>
19 #include <linux/trace.h>
21 #define STM_FTRACE_NR_CHANNELS 1
22 #define STM_FTRACE_CHAN 0
24 static int stm_ftrace_link(struct stm_source_data
*data
);
25 static void stm_ftrace_unlink(struct stm_source_data
*data
);
27 static struct stm_ftrace
{
28 struct stm_source_data data
;
29 struct trace_export ftrace
;
33 .nr_chans
= STM_FTRACE_NR_CHANNELS
,
34 .link
= stm_ftrace_link
,
35 .unlink
= stm_ftrace_unlink
,
40 * stm_ftrace_write() - write data to STM via 'stm_ftrace' source
41 * @buf: buffer containing the data packet
42 * @len: length of the data packet
45 stm_ftrace_write(const void *buf
, unsigned int len
)
47 stm_source_write(&stm_ftrace
.data
, STM_FTRACE_CHAN
, buf
, len
);
50 static int stm_ftrace_link(struct stm_source_data
*data
)
52 struct stm_ftrace
*sf
= container_of(data
, struct stm_ftrace
, data
);
54 sf
->ftrace
.write
= stm_ftrace_write
;
56 return register_ftrace_export(&sf
->ftrace
);
59 static void stm_ftrace_unlink(struct stm_source_data
*data
)
61 struct stm_ftrace
*sf
= container_of(data
, struct stm_ftrace
, data
);
63 unregister_ftrace_export(&sf
->ftrace
);
66 static int __init
stm_ftrace_init(void)
70 ret
= stm_source_register_device(NULL
, &stm_ftrace
.data
);
72 pr_err("Failed to register stm_source - ftrace.\n");
77 static void __exit
stm_ftrace_exit(void)
79 stm_source_unregister_device(&stm_ftrace
.data
);
82 module_init(stm_ftrace_init
);
83 module_exit(stm_ftrace_exit
);
85 MODULE_LICENSE("GPL v2");
86 MODULE_DESCRIPTION("stm_ftrace driver");
87 MODULE_AUTHOR("Chunyan Zhang <zhang.chunyan@linaro.org>");