Commit 79543cf2 authored by Dmitry Torokhov's avatar Dmitry Torokhov Committed by Greg Kroah-Hartman

driver-core: add test module for asynchronous probing

This test module tries to test asynchronous driver probing by having a
driver that sleeps for an extended period of time (5 secs) in its
probe() method. It measures the time needed to register this driver
(with device already registered) and a new device (with driver already
registered). The module will fail to load if the time spent in register
call is more than half the probing sleep time.

As a sanity check the driver will then try to synchronously register
driver and device and fail if registration takes less than half of the
probing sleep time.
Signed-off-by: default avatarDmitry Torokhov <dtor@chromium.org>
Reviewed-by: default avatarOlof Johansson <olofj@chromium.org>
Signed-off-by: default avatarGuenter Roeck <groeck@chromium.org>
Signed-off-by: default avatarThierry Escande <thierry.escande@collabora.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6751667a
......@@ -224,6 +224,8 @@ config DEBUG_TEST_DRIVER_REMOVE
unusable. You should say N here unless you are explicitly looking to
test this functionality.
source "drivers/base/test/Kconfig"
config SYS_HYPERVISOR
bool
default n
......
......@@ -24,5 +24,7 @@ obj-$(CONFIG_PINCTRL) += pinctrl.o
obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o
obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o
obj-y += test/
ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
config TEST_ASYNC_DRIVER_PROBE
tristate "Build kernel module to test asynchronous driver probing"
depends on m
help
Enabling this option produces a kernel module that allows
testing asynchronous driver probing by the device core.
The module name will be test_async_driver_probe.ko
If unsure say N.
obj-$(CONFIG_TEST_ASYNC_DRIVER_PROBE) += test_async_driver_probe.o
/*
* Copyright (C) 2014 Google, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/hrtimer.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/time.h>
#define TEST_PROBE_DELAY (5 * 1000) /* 5 sec */
#define TEST_PROBE_THRESHOLD (TEST_PROBE_DELAY / 2)
static int test_probe(struct platform_device *pdev)
{
dev_info(&pdev->dev, "sleeping for %d msecs in probe\n",
TEST_PROBE_DELAY);
msleep(TEST_PROBE_DELAY);
dev_info(&pdev->dev, "done sleeping\n");
return 0;
}
static struct platform_driver async_driver = {
.driver = {
.name = "test_async_driver",
.owner = THIS_MODULE,
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
},
.probe = test_probe,
};
static struct platform_driver sync_driver = {
.driver = {
.name = "test_sync_driver",
.owner = THIS_MODULE,
.probe_type = PROBE_FORCE_SYNCHRONOUS,
},
.probe = test_probe,
};
static struct platform_device *async_dev_1, *async_dev_2;
static struct platform_device *sync_dev_1;
static int __init test_async_probe_init(void)
{
ktime_t calltime, delta;
unsigned long long duration;
int error;
pr_info("registering first asynchronous device...\n");
async_dev_1 = platform_device_register_simple("test_async_driver", 1,
NULL, 0);
if (IS_ERR(async_dev_1)) {
error = PTR_ERR(async_dev_1);
pr_err("failed to create async_dev_1: %d", error);
return error;
}
pr_info("registering asynchronous driver...\n");
calltime = ktime_get();
error = platform_driver_register(&async_driver);
if (error) {
pr_err("Failed to register async_driver: %d\n", error);
goto err_unregister_async_dev_1;
}
delta = ktime_sub(ktime_get(), calltime);
duration = (unsigned long long) ktime_to_ms(delta);
pr_info("registration took %lld msecs\n", duration);
if (duration > TEST_PROBE_THRESHOLD) {
pr_err("test failed: probe took too long\n");
error = -ETIMEDOUT;
goto err_unregister_async_driver;
}
pr_info("registering second asynchronous device...\n");
calltime = ktime_get();
async_dev_2 = platform_device_register_simple("test_async_driver", 2,
NULL, 0);
if (IS_ERR(async_dev_2)) {
error = PTR_ERR(async_dev_2);
pr_err("failed to create async_dev_2: %d", error);
goto err_unregister_async_driver;
}
delta = ktime_sub(ktime_get(), calltime);
duration = (unsigned long long) ktime_to_ms(delta);
pr_info("registration took %lld msecs\n", duration);
if (duration > TEST_PROBE_THRESHOLD) {
pr_err("test failed: probe took too long\n");
error = -ETIMEDOUT;
goto err_unregister_async_dev_2;
}
pr_info("registering synchronous driver...\n");
error = platform_driver_register(&sync_driver);
if (error) {
pr_err("Failed to register async_driver: %d\n", error);
goto err_unregister_async_dev_2;
}
pr_info("registering synchronous device...\n");
calltime = ktime_get();
sync_dev_1 = platform_device_register_simple("test_sync_driver", 1,
NULL, 0);
if (IS_ERR(async_dev_1)) {
error = PTR_ERR(sync_dev_1);
pr_err("failed to create sync_dev_1: %d", error);
goto err_unregister_sync_driver;
}
delta = ktime_sub(ktime_get(), calltime);
duration = (unsigned long long) ktime_to_ms(delta);
pr_info("registration took %lld msecs\n", duration);
if (duration < TEST_PROBE_THRESHOLD) {
pr_err("test failed: probe was too quick\n");
error = -ETIMEDOUT;
goto err_unregister_sync_dev_1;
}
pr_info("completed successfully");
return 0;
err_unregister_sync_dev_1:
platform_device_unregister(sync_dev_1);
err_unregister_sync_driver:
platform_driver_unregister(&sync_driver);
err_unregister_async_dev_2:
platform_device_unregister(async_dev_2);
err_unregister_async_driver:
platform_driver_unregister(&async_driver);
err_unregister_async_dev_1:
platform_device_unregister(async_dev_1);
return error;
}
module_init(test_async_probe_init);
static void __exit test_async_probe_exit(void)
{
platform_driver_unregister(&async_driver);
platform_driver_unregister(&sync_driver);
platform_device_unregister(async_dev_1);
platform_device_unregister(async_dev_2);
platform_device_unregister(sync_dev_1);
}
module_exit(test_async_probe_exit);
MODULE_DESCRIPTION("Test module for asynchronous driver probing");
MODULE_AUTHOR("Dmitry Torokhov <dtor@chromium.org>");
MODULE_LICENSE("GPL");
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