3 files changed, 172 insertions, 0 deletions
diff --git a/drivers/base/test/Kconfig b/drivers/base/test/Kconfig
new file mode 100644
index 000000000..86e85daa8
--- /dev/null
+++ b/drivers/base/test/Kconfig
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+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.
diff --git a/drivers/base/test/Makefile b/drivers/base/test/Makefile
new file mode 100644
index 000000000..90477c5fd
--- /dev/null
+++ b/drivers/base/test/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_TEST_ASYNC_DRIVER_PROBE)	+= test_async_driver_probe.o
diff --git a/drivers/base/test/test_async_driver_probe.c b/drivers/base/test/test_async_driver_probe.c
new file mode 100644
index 000000000..e7f145d66
--- /dev/null
+++ b/drivers/base/test/test_async_driver_probe.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2014 Google, Inc.
+ */
+
+#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",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+	.probe = test_probe,
+};
+
+static struct platform_driver sync_driver = {
+	.driver = {
+		.name = "test_sync_driver",
+		.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\n", 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\n", 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(sync_dev_1)) {
+		error = PTR_ERR(sync_dev_1);
+		pr_err("failed to create sync_dev_1: %d\n", 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");