[PATCH v0 04/11] stm class: stm_console: Add kernel-console-over-stm driver

From: Alexander Shishkin
Date: Sat Mar 07 2015 - 06:39:11 EST


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: Pratik Patel <pratikp@xxxxxxxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
---
drivers/stm/Kconfig | 10 +++++++
drivers/stm/Makefile | 2 ++
drivers/stm/console.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 92 insertions(+)
create mode 100644 drivers/stm/console.c

diff --git a/drivers/stm/Kconfig b/drivers/stm/Kconfig
index cb3a0d3c4c..6f2db709b1 100644
--- a/drivers/stm/Kconfig
+++ b/drivers/stm/Kconfig
@@ -15,3 +15,13 @@ 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"
+ default N
+ 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/stm/Makefile b/drivers/stm/Makefile
index 1b2725fd04..74baf592db 100644
--- a/drivers/stm/Makefile
+++ b/drivers/stm/Makefile
@@ -3,3 +3,5 @@ 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) += console.o
diff --git a/drivers/stm/console.c b/drivers/stm/console.c
new file mode 100644
index 0000000000..c9d9a8d2ff
--- /dev/null
+++ b/drivers/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

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