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platform: Add test managed platform_device/driver APIs

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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>
Reviewed-by: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20240718210513.3801024-6-sboyd@kernel.org
This commit is contained in:
Stephen Boyd 2024-07-18 14:05:04 -07:00
parent 5c9dd72d83
commit 5ac7973032
7 changed files with 565 additions and 1 deletions
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5
Documentation/dev-tools/kunit/api/index.rst
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@ -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

10
Documentation/dev-tools/kunit/api/platformdevice.rst Normal file
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@ -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:: lib/kunit/platform.c
:export:

1
drivers/base/dd.c
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@ -393,6 +393,7 @@ bool device_is_bound(struct device *dev)
{
return dev->p && klist_node_attached(&dev->p->knode_driver);
}
EXPORT_SYMBOL_GPL(device_is_bound);
static void driver_bound(struct device *dev)
{

20
include/kunit/platform_device.h Normal file
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@ -0,0 +1,20 @@
/* 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 *
kunit_platform_device_alloc(struct kunit *test, const char *name, int id);
int kunit_platform_device_add(struct kunit *test, struct platform_device *pdev);
int kunit_platform_device_prepare_wait_for_probe(struct kunit *test,
struct platform_device *pdev,
struct completion *x);
int kunit_platform_driver_register(struct kunit *test,
struct platform_driver *drv);
#endif

4
lib/kunit/Makefile
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@ -9,7 +9,8 @@ kunit-objs += test.o \
try-catch.o \
executor.o \
attributes.o \
device.o
device.o \
platform.o
ifeq ($(CONFIG_KUNIT_DEBUGFS),y)
kunit-objs += debugfs.o
@ -19,6 +20,7 @@ endif
obj-y += hooks.o
obj-$(CONFIG_KUNIT_TEST) += kunit-test.o
obj-$(CONFIG_KUNIT_TEST) += platform-test.o
# string-stream-test compiles built-in only.
ifeq ($(CONFIG_KUNIT_TEST),y)

224
lib/kunit/platform-test.c Normal file
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@ -0,0 +1,224 @@
// SPDX-License-Identifier: GPL-2.0
/*
* KUnit test for KUnit platform driver infrastructure.
*/
#include <linux/platform_device.h>
#include <kunit/platform_device.h>
#include <kunit/test.h>
/*
* Test that kunit_platform_device_alloc() creates a platform device.
*/
static void kunit_platform_device_alloc_test(struct kunit *test)
{
KUNIT_EXPECT_NOT_ERR_OR_NULL(test,
kunit_platform_device_alloc(test, "kunit-platform", 1));
}
/*
* Test that kunit_platform_device_add() registers a platform device on the
* platform bus with the proper name and id.
*/
static void kunit_platform_device_add_test(struct kunit *test)
{
struct platform_device *pdev;
const char *name = "kunit-platform-add";
const int id = -1;
pdev = kunit_platform_device_alloc(test, name, id);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
KUNIT_EXPECT_EQ(test, 0, kunit_platform_device_add(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 kunit_platform_device_add() called twice with the same device name
* and id fails the second time and properly cleans up.
*/
static void kunit_platform_device_add_twice_fails_test(struct kunit *test)
{
struct platform_device *pdev;
const char *name = "kunit-platform-add-2";
const int id = -1;
pdev = kunit_platform_device_alloc(test, name, id);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_add(test, pdev));
pdev = kunit_platform_device_alloc(test, name, id);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
KUNIT_EXPECT_NE(test, 0, kunit_platform_device_add(test, pdev));
}
static int kunit_platform_device_find_by_name(struct device *dev, const void *data)
{
return strcmp(dev_name(dev), data) == 0;
}
/*
* Test that kunit_platform_device_add() cleans up by removing the platform
* device when the test finishes. */
static void kunit_platform_device_add_cleans_up(struct kunit *test)
{
struct platform_device *pdev;
const char *name = "kunit-platform-clean";
const int id = -1;
struct kunit fake;
struct device *dev;
kunit_init_test(&fake, "kunit_platform_device_add_fake_test", NULL);
KUNIT_ASSERT_EQ(test, fake.status, KUNIT_SUCCESS);
pdev = kunit_platform_device_alloc(&fake, name, id);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_add(&fake, pdev));
dev = bus_find_device(&platform_bus_type, NULL, name,
kunit_platform_device_find_by_name);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
put_device(dev);
/* Remove pdev */
kunit_cleanup(&fake);
/*
* Failing to migrate the kunit_resource would lead to an extra
* put_device() call on the platform device. The best we can do here is
* make sure the device no longer exists on the bus, but if something
* is wrong we'll see a refcount underflow here. We can't test for a
* refcount underflow because the kref matches the lifetime of the
* device which should already be freed and could be used by something
* else.
*/
dev = bus_find_device(&platform_bus_type, NULL, name,
kunit_platform_device_find_by_name);
KUNIT_EXPECT_PTR_EQ(test, NULL, dev);
put_device(dev);
}
/*
* Test suite for struct platform_device kunit APIs
*/
static struct kunit_case kunit_platform_device_test_cases[] = {
KUNIT_CASE(kunit_platform_device_alloc_test),
KUNIT_CASE(kunit_platform_device_add_test),
KUNIT_CASE(kunit_platform_device_add_twice_fails_test),
KUNIT_CASE(kunit_platform_device_add_cleans_up),
{}
};
static struct kunit_suite kunit_platform_device_suite = {
.name = "kunit_platform_device",
.test_cases = kunit_platform_device_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 kunit_platform_driver_register() registers a driver that probes. */
static void kunit_platform_driver_register_test(struct kunit *test)
{
struct platform_device *pdev;
struct kunit_platform_driver_test_context *ctx;
DECLARE_COMPLETION_ONSTACK(comp);
const char *name = "kunit-platform-register";
ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);
pdev = kunit_platform_device_alloc(test, name, -1);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_add(test, pdev));
ctx->pdrv.probe = kunit_platform_driver_probe;
ctx->pdrv.driver.name = name;
ctx->pdrv.driver.owner = THIS_MODULE;
KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_prepare_wait_for_probe(test, pdev, &comp));
KUNIT_EXPECT_EQ(test, 0, kunit_platform_driver_register(test, &ctx->pdrv));
KUNIT_EXPECT_NE(test, 0, wait_for_completion_timeout(&comp, 3 * HZ));
KUNIT_EXPECT_STREQ(test, ctx->data, test_data);
}
/*
* Test that kunit_platform_device_prepare_wait_for_probe() completes the completion
* when the device is already probed.
*/
static void kunit_platform_device_prepare_wait_for_probe_completes_when_already_probed(struct kunit *test)
{
struct platform_device *pdev;
struct kunit_platform_driver_test_context *ctx;
DECLARE_COMPLETION_ONSTACK(comp);
const char *name = "kunit-platform-wait";
ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);
pdev = kunit_platform_device_alloc(test, name, -1);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_add(test, pdev));
ctx->pdrv.probe = kunit_platform_driver_probe;
ctx->pdrv.driver.name = name;
ctx->pdrv.driver.owner = THIS_MODULE;
/* Make sure driver has actually probed */
KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_prepare_wait_for_probe(test, pdev, &comp));
KUNIT_ASSERT_EQ(test, 0, kunit_platform_driver_register(test, &ctx->pdrv));
KUNIT_ASSERT_NE(test, 0, wait_for_completion_timeout(&comp, 3 * HZ));
reinit_completion(&comp);
KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_prepare_wait_for_probe(test, pdev, &comp));
KUNIT_EXPECT_NE(test, 0, wait_for_completion_timeout(&comp, HZ));
}
static struct kunit_case kunit_platform_driver_test_cases[] = {
KUNIT_CASE(kunit_platform_driver_register_test),
KUNIT_CASE(kunit_platform_device_prepare_wait_for_probe_completes_when_already_probed),
{}
};
/*
* Test suite for struct platform_driver kunit APIs
*/
static struct kunit_suite kunit_platform_driver_suite = {
.name = "kunit_platform_driver",
.test_cases = kunit_platform_driver_test_cases,
};
kunit_test_suites(
&kunit_platform_device_suite,
&kunit_platform_driver_suite,
);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("KUnit test for KUnit platform driver infrastructure");

302
lib/kunit/platform.c Normal file
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@ -0,0 +1,302 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Test managed platform driver
*/
#include <linux/completion.h>
#include <linux/device/bus.h>
#include <linux/device/driver.h>
#include <linux/platform_device.h>
#include <kunit/platform_device.h>
#include <kunit/resource.h>
struct kunit_platform_device_alloc_params {
const char *name;
int id;
};
static int kunit_platform_device_alloc_init(struct kunit_resource *res, void *context)
{
struct kunit_platform_device_alloc_params *params = context;
struct platform_device *pdev;
pdev = platform_device_alloc(params->name, params->id);
if (!pdev)
return -ENOMEM;
res->data = pdev;
return 0;
}
static void kunit_platform_device_alloc_exit(struct kunit_resource *res)
{
struct platform_device *pdev = res->data;
platform_device_put(pdev);
}
/**
* kunit_platform_device_alloc() - 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 *
kunit_platform_device_alloc(struct kunit *test, const char *name, int id)
{
struct kunit_platform_device_alloc_params params = {
.name = name,
.id = id,
};
return kunit_alloc_resource(test,
kunit_platform_device_alloc_init,
kunit_platform_device_alloc_exit,
GFP_KERNEL, &params);
}
EXPORT_SYMBOL_GPL(kunit_platform_device_alloc);
static void kunit_platform_device_add_exit(struct kunit_resource *res)
{
struct platform_device *pdev = res->data;
platform_device_unregister(pdev);
}
static bool
kunit_platform_device_alloc_match(struct kunit *test,
struct kunit_resource *res, void *match_data)
{
struct platform_device *pdev = match_data;
return res->data == pdev && res->free == kunit_platform_device_alloc_exit;
}
KUNIT_DEFINE_ACTION_WRAPPER(platform_device_unregister_wrapper,
platform_device_unregister, struct platform_device *);
/**
* kunit_platform_device_add() - 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 kunit_platform_device_add(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, kunit_platform_device_alloc_match, pdev);
if (res) {
/*
* Transfer the reference count of the platform device if it
* was allocated with kunit_platform_device_alloc(). In this
* case, calling platform_device_put() when the test exits from
* kunit_platform_device_alloc_exit() would lead to reference
* count underflow because platform_device_unregister_wrapper()
* calls platform_device_unregister() which also calls
* platform_device_put().
*
* Usually callers transfer the refcount initialized in
* platform_device_alloc() to platform_device_add() by calling
* platform_device_unregister() when platform_device_add()
* succeeds or platform_device_put() when it fails. KUnit has to
* keep this straight by redirecting the free routine for the
* resource to the right function. Luckily this only has to
* account for the success scenario.
*/
res->free = kunit_platform_device_add_exit;
kunit_put_resource(res);
} else {
ret = kunit_add_action_or_reset(test, platform_device_unregister_wrapper, pdev);
if (ret)
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(kunit_platform_device_add);
struct kunit_platform_device_probe_nb {
struct completion *x;
struct device *dev;
struct notifier_block nb;
};
static int kunit_platform_device_probe_notify(struct notifier_block *nb,
unsigned long event, void *data)
{
struct kunit_platform_device_probe_nb *knb;
struct device *dev = data;
knb = container_of(nb, struct kunit_platform_device_probe_nb, nb);
if (event != BUS_NOTIFY_BOUND_DRIVER || knb->dev != dev)
return NOTIFY_DONE;
complete(knb->x);
return NOTIFY_OK;
}
static void kunit_platform_device_probe_nb_remove(void *nb)
{
bus_unregister_notifier(&platform_bus_type, nb);
}
/**
* kunit_platform_device_prepare_wait_for_probe() - Prepare a completion
* variable to wait for a platform device to probe
* @test: test context
* @pdev: platform device to prepare to wait for probe of
* @x: completion variable completed when @dev has probed
*
* Prepare a completion variable @x to wait for @pdev to probe. Waiting on the
* completion forces a preemption, allowing the platform driver to probe.
*
* Example
*
* .. code-block:: c
*
* static int kunit_platform_driver_probe(struct platform_device *pdev)
* {
* return 0;
* }
*
* static void kunit_platform_driver_test(struct kunit *test)
* {
* struct platform_device *pdev;
* struct platform_driver *pdrv;
* DECLARE_COMPLETION_ONSTACK(comp);
*
* pdev = kunit_platform_device_alloc(test, "kunit-platform", -1);
* KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
* KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_add(test, pdev));
*
* pdrv = kunit_kzalloc(test, sizeof(*pdrv), GFP_KERNEL);
* KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdrv);
*
* pdrv->probe = kunit_platform_driver_probe;
* pdrv->driver.name = "kunit-platform";
* pdrv->driver.owner = THIS_MODULE;
*
* KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_prepare_wait_for_probe(test, pdev, &comp));
* KUNIT_ASSERT_EQ(test, 0, kunit_platform_driver_register(test, pdrv));
*
* KUNIT_EXPECT_NE(test, 0, wait_for_completion_timeout(&comp, 3 * HZ));
* }
*
* Return: 0 on success, negative errno on failure.
*/
int kunit_platform_device_prepare_wait_for_probe(struct kunit *test,
struct platform_device *pdev,
struct completion *x)
{
struct device *dev = &pdev->dev;
struct kunit_platform_device_probe_nb *knb;
bool bound;
knb = kunit_kzalloc(test, sizeof(*knb), GFP_KERNEL);
if (!knb)
return -ENOMEM;
knb->nb.notifier_call = kunit_platform_device_probe_notify;
knb->dev = dev;
knb->x = x;
device_lock(dev);
bound = device_is_bound(dev);
if (bound) {
device_unlock(dev);
complete(x);
kunit_kfree(test, knb);
return 0;
}
bus_register_notifier(&platform_bus_type, &knb->nb);
device_unlock(&pdev->dev);
return kunit_add_action_or_reset(test, kunit_platform_device_probe_nb_remove, &knb->nb);
}
EXPORT_SYMBOL_GPL(kunit_platform_device_prepare_wait_for_probe);
KUNIT_DEFINE_ACTION_WRAPPER(platform_driver_unregister_wrapper,
platform_driver_unregister, struct platform_driver *);
/**
* kunit_platform_driver_register() - 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.
*
* 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, kunit_platform_driver_register(test, &ctx->pdrv));
* <... wait for driver to probe ...>
* KUNIT_EXPECT_STREQ(test, ctx->data, "test data");
* }
*
* Return: 0 on success, negative errno on failure.
*/
int kunit_platform_driver_register(struct kunit *test,
struct platform_driver *drv)
{
int ret;
ret = platform_driver_register(drv);
if (ret)
return ret;
return kunit_add_action_or_reset(test, platform_driver_unregister_wrapper, drv);
}
EXPORT_SYMBOL_GPL(kunit_platform_driver_register);