[PATCH v4 05/10] platform: Add test managed platform_device/driver APIs

Stephen Boyd
2024-04-22T23:24:12Z

Introduce KUnit resource wrappers around platform_driver_register(),
platform_device_alloc(), and platform_device_add() so that test authors
can register platform drivers/devices from their tests and have the
drivers/devices automatically be unregistered when the test is done.

This makes test setup code simpler when a platform driver or platform
device is needed. Add a few test cases at the same time to make sure the
APIs work as intended.

Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
---
Documentation/dev-tools/kunit/api/index.rst | 5 +
.../dev-tools/kunit/api/platformdevice.rst | 10 +
drivers/base/test/Makefile | 3 +
drivers/base/test/platform_kunit-test.c | 140 ++++++++++++++
drivers/base/test/platform_kunit.c | 174 ++++++++++++++++++
include/kunit/platform_device.h | 15 ++
6 files changed, 347 insertions(+)
create mode 100644 Documentation/dev-tools/kunit/api/platformdevice.rst
create mode 100644 drivers/base/test/platform_kunit-test.c
create mode 100644 drivers/base/test/platform_kunit.c
create mode 100644 include/kunit/platform_device.h

diff --git a/Documentation/dev-tools/kunit/api/index.rst b/Documentation/dev-tools/kunit/api/index.rst
index 282befa17edf..02b26f5e8750 100644
--- a/Documentation/dev-tools/kunit/api/index.rst
+++ b/Documentation/dev-tools/kunit/api/index.rst
@@ -10,6 +10,7 @@ API Reference
resource
functionredirection
of
+ platformdevice

This page documents the KUnit kernel testing API. It is divided into the
@@ -36,3 +37,7 @@ Driver KUnit API
Documentation/dev-tools/kunit/api/of.rst

- Documents the KUnit device tree (OF) API
+
+Documentation/dev-tools/kunit/api/platformdevice.rst
+
+ - Documents the KUnit platform device API
diff --git a/Documentation/dev-tools/kunit/api/platformdevice.rst b/Documentation/dev-tools/kunit/api/platformdevice.rst
new file mode 100644
index 000000000000..b228fb6558c2
--- /dev/null
+++ b/Documentation/dev-tools/kunit/api/platformdevice.rst
@@ -0,0 +1,10 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===================
+Platform Device API
+===================
+
+The KUnit platform device API is used to test platform devices.
+
+.. kernel-doc:: drivers/base/test/platform_kunit.c
+ :export:
diff --git a/drivers/base/test/Makefile b/drivers/base/test/Makefile
index e321dfc7e922..740aef267fbe 100644
--- a/drivers/base/test/Makefile
+++ b/drivers/base/test/Makefile
@@ -1,8 +1,11 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_TEST_ASYNC_DRIVER_PROBE) += test_async_driver_probe.o

+obj-$(CONFIG_KUNIT) += platform_kunit.o
+
obj-$(CONFIG_DM_KUNIT_TEST) += root-device-test.o
obj-$(CONFIG_DM_KUNIT_TEST) += platform-device-test.o
+obj-$(CONFIG_DM_KUNIT_TEST) += platform_kunit-test.o

obj-$(CONFIG_DRIVER_PE_KUNIT_TEST) += property-entry-test.o
CFLAGS_property-entry-test.o += $(DISABLE_STRUCTLEAK_PLUGIN)
diff --git a/drivers/base/test/platform_kunit-test.c b/drivers/base/test/platform_kunit-test.c
new file mode 100644
index 000000000000..ce545532d209
--- /dev/null
+++ b/drivers/base/test/platform_kunit-test.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit test for platform driver infrastructure.
+ */
+
+#include <linux/platform_device.h>
+
+#include <kunit/platform_device.h>
+#include <kunit/test.h>
+
+static const char * const kunit_devname = "kunit-platform";
+
+/*
+ * Test that platform_device_alloc_kunit() creates a platform device.
+ */
+static void platform_device_alloc_kunit_test(struct kunit *test)
+{
+ KUNIT_EXPECT_NOT_ERR_OR_NULL(test,
+ platform_device_alloc_kunit(test, kunit_devname, 1));
+}
+
+/*
+ * Test that platform_device_add_kunit() registers a platform device on the
+ * platform bus with the proper name and id.
+ */
+static void platform_device_add_kunit_test(struct kunit *test)
+{
+ struct platform_device *pdev;
+ const char *name = kunit_devname;
+ const int id = -1;
+
+ pdev = platform_device_alloc_kunit(test, name, id);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+
+ KUNIT_EXPECT_EQ(test, 0, platform_device_add_kunit(test, pdev));
+ KUNIT_EXPECT_TRUE(test, dev_is_platform(&pdev->dev));
+ KUNIT_EXPECT_STREQ(test, pdev->name, name);
+ KUNIT_EXPECT_EQ(test, pdev->id, id);
+}
+
+/*
+ * Test that platform_device_add_kunit() called twice with the same device name
+ * and id fails the second time and properly cleans up.
+ */
+static void platform_device_add_kunit_twice_fails_test(struct kunit *test)
+{
+ struct platform_device *pdev;
+ const char *name = kunit_devname;
+ const int id = -1;
+
+ pdev = platform_device_alloc_kunit(test, name, id);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+ KUNIT_ASSERT_EQ(test, 0, platform_device_add_kunit(test, pdev));
+
+ pdev = platform_device_alloc_kunit(test, name, id);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+
+ KUNIT_EXPECT_NE(test, 0, platform_device_add_kunit(test, pdev));
+}
+
+/*
+ * Test suite for struct platform_device kunit APIs
+ */
+static struct kunit_case platform_device_kunit_test_cases[] = {
+ KUNIT_CASE(platform_device_alloc_kunit_test),
+ KUNIT_CASE(platform_device_add_kunit_test),
+ KUNIT_CASE(platform_device_add_kunit_twice_fails_test),
+ {}
+};
+
+static struct kunit_suite platform_device_kunit_suite = {
+ .name = "platform_device_kunit",
+ .test_cases = platform_device_kunit_test_cases,
+};
+
+struct kunit_platform_driver_test_context {
+ struct platform_driver pdrv;
+ const char *data;
+};
+
+static const char * const test_data = "test data";
+
+static inline struct kunit_platform_driver_test_context *
+to_test_context(struct platform_device *pdev)
+{
+ return container_of(to_platform_driver(pdev->dev.driver),
+ struct kunit_platform_driver_test_context,
+ pdrv);
+}
+
+static int kunit_platform_driver_probe(struct platform_device *pdev)
+{
+ struct kunit_platform_driver_test_context *ctx;
+
+ ctx = to_test_context(pdev);
+ ctx->data = test_data;
+
+ return 0;
+}
+
+/* Test that platform_driver_register_kunit() registers a driver that probes. */
+static void platform_driver_register_kunit_test(struct kunit *test)
+{
+ struct platform_device *pdev;
+ struct kunit_platform_driver_test_context *ctx;
+
+ ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);
+
+ pdev = platform_device_alloc_kunit(test, kunit_devname, -1);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+ KUNIT_ASSERT_EQ(test, 0, platform_device_add_kunit(test, pdev));
+
+ ctx->pdrv.probe = kunit_platform_driver_probe;
+ ctx->pdrv.driver.name = kunit_devname;
+ ctx->pdrv.driver.owner = THIS_MODULE;
+
+ KUNIT_EXPECT_EQ(test, 0, platform_driver_register_kunit(test, &ctx->pdrv));
+ KUNIT_EXPECT_STREQ(test, ctx->data, test_data);
+}
+
+static struct kunit_case platform_driver_kunit_test_cases[] = {
+ KUNIT_CASE(platform_driver_register_kunit_test),
+ {}
+};
+
+/*
+ * Test suite for struct platform_driver kunit APIs
+ */
+static struct kunit_suite platform_driver_kunit_suite = {
+ .name = "platform_driver_kunit",
+ .test_cases = platform_driver_kunit_test_cases,
+};
+
+kunit_test_suites(
+ &platform_device_kunit_suite,
+ &platform_driver_kunit_suite,
+);
+
+MODULE_LICENSE("GPL");
diff --git a/drivers/base/test/platform_kunit.c b/drivers/base/test/platform_kunit.c
new file mode 100644
index 000000000000..54af6db2a6d8
--- /dev/null
+++ b/drivers/base/test/platform_kunit.c
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test managed platform driver
+ */
+
+#include <linux/device/driver.h>
+#include <linux/platform_device.h>
+
+#include <kunit/platform_device.h>
+#include <kunit/resource.h>
+
+/**
+ * platform_device_alloc_kunit() - Allocate a KUnit test managed platform device
+ * @test: test context
+ * @name: device name of platform device to alloc
+ * @id: identifier of platform device to alloc.
+ *
+ * Allocate a test managed platform device. The device is put when the test completes.
+ *
+ * Return: Allocated platform device on success, NULL on failure.
+ */
+struct platform_device *
+platform_device_alloc_kunit(struct kunit *test, const char *name, int id)
+{
+ struct platform_device *pdev;
+
+ pdev = platform_device_alloc(name, id);
+ if (!pdev)
+ return NULL;
+
+ if (kunit_add_action_or_reset(test, (kunit_action_t *)&platform_device_put, pdev))
+ return NULL;
+
+ return pdev;
+}
+EXPORT_SYMBOL_GPL(platform_device_alloc_kunit);
+
+static void platform_device_add_kunit_exit(struct kunit_resource *res)
+{
+ struct platform_device *pdev = res->data;
+
+ platform_device_unregister(pdev);
+}
+
+static bool
+platform_device_alloc_kunit_match(struct kunit *test,
+ struct kunit_resource *res, void *match_data)
+{
+ struct platform_device *pdev = match_data;
+
+ return res->data == pdev;
+}
+
+/**
+ * platform_device_add_kunit() - Register a KUnit test managed platform device
+ * @test: test context
+ * @pdev: platform device to add
+ *
+ * Register a test managed platform device. The device is unregistered when the
+ * test completes.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int platform_device_add_kunit(struct kunit *test, struct platform_device *pdev)
+{
+ struct kunit_resource *res;
+ int ret;
+
+ ret = platform_device_add(pdev);
+ if (ret)
+ return ret;
+
+ res = kunit_find_resource(test, platform_device_alloc_kunit_match, pdev);
+ if (res) {
+ /*
+ * Transfer the reference count of the platform device if it was
+ * allocated with platform_device_alloc_kunit(). In that case,
+ * calling platform_device_put() leads to reference count
+ * underflow because platform_device_unregister() does it for
+ * us and we call platform_device_unregister() from
+ * platform_device_add_kunit_exit().
+ *
+ * Usually callers transfer the refcount from
+ * platform_device_alloc() to platform_device_add() and simply
+ * call platform_device_unregister() when done, but with kunit
+ * we have to keep this straight by redirecting the free
+ * routine for the resource.
+ */
+ res->free = platform_device_add_kunit_exit;
+ kunit_put_resource(res);
+ } else if (kunit_add_action_or_reset(test,
+ (kunit_action_t *)&platform_device_unregister,
+ pdev)) {
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(platform_device_add_kunit);
+
+/**
+ * platform_driver_register_kunit() - Register a KUnit test managed platform driver
+ * @test: test context
+ * @drv: platform driver to register
+ *
+ * Register a test managed platform driver. This allows callers to embed the
+ * @drv in a container structure and use container_of() in the probe function
+ * to pass information to KUnit tests. It can be assumed that the driver has
+ * probed when this function returns.
+ *
+ * Example
+ *
+ * .. code-block:: c
+ *
+ * struct kunit_test_context {
+ * struct platform_driver pdrv;
+ * const char *data;
+ * };
+ *
+ * static inline struct kunit_test_context *
+ * to_test_context(struct platform_device *pdev)
+ * {
+ * return container_of(to_platform_driver(pdev->dev.driver),
+ * struct kunit_test_context,
+ * pdrv);
+ * }
+ *
+ * static int kunit_platform_driver_probe(struct platform_device *pdev)
+ * {
+ * struct kunit_test_context *ctx;
+ *
+ * ctx = to_test_context(pdev);
+ * ctx->data = "test data";
+ *
+ * return 0;
+ * }
+ *
+ * static void kunit_platform_driver_test(struct kunit *test)
+ * {
+ * struct kunit_test_context *ctx;
+ *
+ * ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+ * KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);
+ *
+ * ctx->pdrv.probe = kunit_platform_driver_probe;
+ * ctx->pdrv.driver.name = "kunit-platform";
+ * ctx->pdrv.driver.owner = THIS_MODULE;
+ *
+ * KUNIT_EXPECT_EQ(test, 0, platform_driver_register_kunit(test, &ctx->pdrv));
+ * KUNIT_EXPECT_STREQ(test, ctx->data, "test data");
+ * }
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int platform_driver_register_kunit(struct kunit *test,
+ struct platform_driver *drv)
+{
+ int ret;
+
+ ret = platform_driver_register(drv);
+ if (ret)
+ return ret;
+
+ /*
+ * Wait for the driver to probe (or at least flush out of the deferred
+ * workqueue)
+ */
+ wait_for_device_probe();
+
+ return kunit_add_action_or_reset(test,
+ (kunit_action_t *)&platform_driver_unregister,
+ drv);
+}
+EXPORT_SYMBOL_GPL(platform_driver_register_kunit);
diff --git a/include/kunit/platform_device.h b/include/kunit/platform_device.h
new file mode 100644
index 000000000000..28d28abf15a4
--- /dev/null
+++ b/include/kunit/platform_device.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _KUNIT_PLATFORM_DRIVER_H
+#define _KUNIT_PLATFORM_DRIVER_H
+
+struct kunit;
+struct platform_device;
+struct platform_driver;
+
+struct platform_device *
+platform_device_alloc_kunit(struct kunit *test, const char *name, int id);
+int platform_device_add_kunit(struct kunit *test, struct platform_device *pdev);
+
+int platform_driver_register_kunit(struct kunit *test, struct platform_driver *drv);
+
+#endif
--