Re: [PATCH v3 04/11] stm class: stm_console: Add kernel-console-over-stm driver

[Mathieu Poirier]

On 6 July 2015 at 04:08, Alexander Shishkin
<alexander.shishkin@xxxxxxxxxxxxxxx> wrote:
> This is a simple stm_source class device driver (kernelspace stm trace
> source) that registers a console and sends kernel messages over STM
> devices.
>
> Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> ---
>  drivers/hwtracing/stm/Kconfig   |  9 +++++
>  drivers/hwtracing/stm/Makefile  |  4 +++
>  drivers/hwtracing/stm/console.c | 80 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 93 insertions(+)
>  create mode 100644 drivers/hwtracing/stm/console.c
>
> diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig
> index 4fdb8f46d2..583c222218 100644
> --- a/drivers/hwtracing/stm/Kconfig
> +++ b/drivers/hwtracing/stm/Kconfig
> @@ -14,3 +14,12 @@ config STM_DUMMY
>           and discards your data. Use for stm class testing.
>
>           If you don't know what this is, say N.
> +
> +config STM_SOURCE_CONSOLE
> +       tristate "Kernel console over STM devices"
> +       help
> +         This is a kernel space trace source that sends kernel log
> +         messages to trace hosts over STM devices.
> +
> +         If you want to send kernel console messages over STM devices,
> +         say Y.
> diff --git a/drivers/hwtracing/stm/Makefile b/drivers/hwtracing/stm/Makefile
> index 1b2725fd04..f9312c38dd 100644
> --- a/drivers/hwtracing/stm/Makefile
> +++ b/drivers/hwtracing/stm/Makefile
> @@ -3,3 +3,7 @@ obj-$(CONFIG_STM)       += stm_core.o
>  stm_core-y             := core.o policy.o
>
>  obj-$(CONFIG_STM_DUMMY)        += dummy_stm.o
> +
> +obj-$(CONFIG_STM_SOURCE_CONSOLE)       += stm_console.o
> +
> +stm_console-y          := console.o
> diff --git a/drivers/hwtracing/stm/console.c b/drivers/hwtracing/stm/console.c
> new file mode 100644
> index 0000000000..c9d9a8d2ff
> --- /dev/null
> +++ b/drivers/hwtracing/stm/console.c
> @@ -0,0 +1,80 @@
> +/*
> + * Simple kernel console driver for STM devices
> + * Copyright (c) 2014, Intel Corporation.
> + *
> + * 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 console will send kernel messages over STM devices to a trace host.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/console.h>
> +#include <linux/slab.h>
> +#include <linux/stm.h>
> +
> +static int stm_console_link(struct stm_source_data *data);
> +static void stm_console_unlink(struct stm_source_data *data);
> +
> +static struct stm_console {
> +       struct stm_source_data  data;
> +       struct console          console;
> +} stm_console = {
> +       .data   = {
> +               .name           = "console",
> +               .nr_chans       = 1,
> +               .link           = stm_console_link,
> +               .unlink         = stm_console_unlink,
> +       },
> +};
> +
> +static void
> +stm_console_write(struct console *con, const char *buf, unsigned len)
> +{
> +       struct stm_console *sc = container_of(con, struct stm_console, console);
> +
> +       stm_source_write(&sc->data, 0, buf, len);
> +}
> +
> +static int stm_console_link(struct stm_source_data *data)
> +{
> +       struct stm_console *sc = container_of(data, struct stm_console, data);
> +
> +       strcpy(sc->console.name, "stm_console");
> +       sc->console.write = stm_console_write;
> +       sc->console.flags = CON_ENABLED | CON_PRINTBUFFER;
> +       register_console(&sc->console);
> +
> +       return 0;
> +}
> +
> +static void stm_console_unlink(struct stm_source_data *data)
> +{
> +       struct stm_console *sc = container_of(data, struct stm_console, data);
> +
> +       unregister_console(&sc->console);
> +}
> +
> +static int stm_console_init(void)
> +{
> +       return stm_source_register_device(NULL, &stm_console.data);
> +}
> +
> +static void stm_console_exit(void)
> +{
> +       stm_source_unregister_device(&stm_console.data);
> +}
> +
> +module_init(stm_console_init);
> +module_exit(stm_console_exit);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("stm_console driver");
> +MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>");
> --
> 2.1.4
>

Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
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