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stm class: Factor out default framing protocol

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The STP framing pattern that the stm class implicitly applies to the
data payload is, in fact, a protocol. This patch moves the relevant code
out of the stm core into its own driver module.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Shishkin 2018-10-05 15:42:56 +03:00 committed by Greg Kroah-Hartman
parent d279a38020
commit a02509f301
3 changed files with 67 additions and 0 deletions
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15
drivers/hwtracing/stm/Kconfig
View File

@ -11,6 +11,21 @@ config STM
if STM
config STM_PROTO_BASIC
tristate "Basic STM framing protocol driver"
default CONFIG_STM
help
This is a simple framing protocol for sending data over STM
devices. This was the protocol that the STM framework used
exclusively until the MIPI SyS-T support was added. Use this
driver for compatibility with your existing STM setup.
The receiving side only needs to be able to decode the MIPI
STP protocol in order to extract the data.
If you want to be able to use the basic protocol or want the
backwards compatibility for your existing setup, say Y.
config STM_DUMMY
tristate "Dummy STM driver"
help

4
drivers/hwtracing/stm/Makefile
View File

@ -3,6 +3,10 @@ obj-$(CONFIG_STM) += stm_core.o
stm_core-y := core.o policy.o
obj-$(CONFIG_STM_PROTO_BASIC) += stm_p_basic.o
stm_p_basic-y := p_basic.o
obj-$(CONFIG_STM_DUMMY) += dummy_stm.o
obj-$(CONFIG_STM_SOURCE_CONSOLE) += stm_console.o

48
drivers/hwtracing/stm/p_basic.c Normal file
View File

@ -0,0 +1,48 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Basic framing protocol for STM devices.
* Copyright (c) 2018, Intel Corporation.
*/
#include <linux/module.h>
#include <linux/device.h>
#include <linux/stm.h>
#include "stm.h"
static ssize_t basic_write(struct stm_data *data, struct stm_output *output,
unsigned int chan, const char *buf, size_t count)
{
unsigned int c = output->channel + chan;
unsigned int m = output->master;
const unsigned char nil = 0;
ssize_t sz;
sz = stm_data_write(data, m, c, true, buf, count);
if (sz > 0)
data->packet(data, m, c, STP_PACKET_FLAG, 0, 0, &nil);
return sz;
}
static const struct stm_protocol_driver basic_pdrv = {
.owner = THIS_MODULE,
.name = "p_basic",
.write = basic_write,
};
static int basic_stm_init(void)
{
return stm_register_protocol(&basic_pdrv);
}
static void basic_stm_exit(void)
{
stm_unregister_protocol(&basic_pdrv);
}
module_init(basic_stm_init);
module_exit(basic_stm_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Basic STM framing protocol driver");
MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");