1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Test managed platform driver
  4 */
  5
  6#include <linux/completion.h>
  7#include <linux/device/bus.h>
  8#include <linux/device/driver.h>
  9#include <linux/platform_device.h>
 10
 11#include <kunit/platform_device.h>
 12#include <kunit/resource.h>
 13
 14struct kunit_platform_device_alloc_params {
 15	const char *name;
 16	int id;
 17};
 18
 19static int kunit_platform_device_alloc_init(struct kunit_resource *res, void *context)
 20{
 21	struct kunit_platform_device_alloc_params *params = context;
 22	struct platform_device *pdev;
 23
 24	pdev = platform_device_alloc(params->name, params->id);
 25	if (!pdev)
 26		return -ENOMEM;
 27
 28	res->data = pdev;
 29
 30	return 0;
 31}
 32
 33static void kunit_platform_device_alloc_exit(struct kunit_resource *res)
 34{
 35	struct platform_device *pdev = res->data;
 36
 37	platform_device_put(pdev);
 38}
 39
 40/**
 41 * kunit_platform_device_alloc() - Allocate a KUnit test managed platform device
 42 * @test: test context
 43 * @name: device name of platform device to alloc
 44 * @id: identifier of platform device to alloc.
 45 *
 46 * Allocate a test managed platform device. The device is put when the test completes.
 47 *
 48 * Return: Allocated platform device on success, NULL on failure.
 49 */
 50struct platform_device *
 51kunit_platform_device_alloc(struct kunit *test, const char *name, int id)
 52{
 53	struct kunit_platform_device_alloc_params params = {
 54		.name = name,
 55		.id = id,
 56	};
 57
 58	return kunit_alloc_resource(test,
 59				    kunit_platform_device_alloc_init,
 60				    kunit_platform_device_alloc_exit,
 61				    GFP_KERNEL, &params);
 62}
 63EXPORT_SYMBOL_GPL(kunit_platform_device_alloc);
 64
 65static void kunit_platform_device_add_exit(struct kunit_resource *res)
 66{
 67	struct platform_device *pdev = res->data;
 68
 69	platform_device_unregister(pdev);
 70}
 71
 72static bool
 73kunit_platform_device_alloc_match(struct kunit *test,
 74				  struct kunit_resource *res, void *match_data)
 75{
 76	struct platform_device *pdev = match_data;
 77
 78	return res->data == pdev && res->free == kunit_platform_device_alloc_exit;
 79}
 80
 81KUNIT_DEFINE_ACTION_WRAPPER(platform_device_unregister_wrapper,
 82			    platform_device_unregister, struct platform_device *);
 83/**
 84 * kunit_platform_device_add() - Register a KUnit test managed platform device
 85 * @test: test context
 86 * @pdev: platform device to add
 87 *
 88 * Register a test managed platform device. The device is unregistered when the
 89 * test completes.
 90 *
 91 * Return: 0 on success, negative errno on failure.
 92 */
 93int kunit_platform_device_add(struct kunit *test, struct platform_device *pdev)
 94{
 95	struct kunit_resource *res;
 96	int ret;
 97
 98	ret = platform_device_add(pdev);
 99	if (ret)
100		return ret;
101
102	res = kunit_find_resource(test, kunit_platform_device_alloc_match, pdev);
103	if (res) {
104		/*
105		 * Transfer the reference count of the platform device if it
106		 * was allocated with kunit_platform_device_alloc(). In this
107		 * case, calling platform_device_put() when the test exits from
108		 * kunit_platform_device_alloc_exit() would lead to reference
109		 * count underflow because platform_device_unregister_wrapper()
110		 * calls platform_device_unregister() which also calls
111		 * platform_device_put().
112		 *
113		 * Usually callers transfer the refcount initialized in
114		 * platform_device_alloc() to platform_device_add() by calling
115		 * platform_device_unregister() when platform_device_add()
116		 * succeeds or platform_device_put() when it fails. KUnit has to
117		 * keep this straight by redirecting the free routine for the
118		 * resource to the right function. Luckily this only has to
119		 * account for the success scenario.
120		 */
121		res->free = kunit_platform_device_add_exit;
122		kunit_put_resource(res);
123	} else {
124		ret = kunit_add_action_or_reset(test, platform_device_unregister_wrapper, pdev);
125		if (ret)
126			return ret;
127	}
128
129	return 0;
130}
131EXPORT_SYMBOL_GPL(kunit_platform_device_add);
132
133struct kunit_platform_device_probe_nb {
134	struct completion *x;
135	struct device *dev;
136	struct notifier_block nb;
137};
138
139static int kunit_platform_device_probe_notify(struct notifier_block *nb,
140					      unsigned long event, void *data)
141{
142	struct kunit_platform_device_probe_nb *knb;
143	struct device *dev = data;
144
145	knb = container_of(nb, struct kunit_platform_device_probe_nb, nb);
146	if (event != BUS_NOTIFY_BOUND_DRIVER || knb->dev != dev)
147		return NOTIFY_DONE;
148
149	complete(knb->x);
150
151	return NOTIFY_OK;
152}
153
154static void kunit_platform_device_probe_nb_remove(void *nb)
155{
156	bus_unregister_notifier(&platform_bus_type, nb);
157}
158
159/**
160 * kunit_platform_device_prepare_wait_for_probe() - Prepare a completion
161 * variable to wait for a platform device to probe
162 * @test: test context
163 * @pdev: platform device to prepare to wait for probe of
164 * @x: completion variable completed when @dev has probed
165 *
166 * Prepare a completion variable @x to wait for @pdev to probe. Waiting on the
167 * completion forces a preemption, allowing the platform driver to probe.
168 *
169 * Example
170 *
171 * .. code-block:: c
172 *
173 *	static int kunit_platform_driver_probe(struct platform_device *pdev)
174 *	{
175 *		return 0;
176 *	}
177 *
178 *	static void kunit_platform_driver_test(struct kunit *test)
179 *	{
180 *		struct platform_device *pdev;
181 *		struct platform_driver *pdrv;
182 *		DECLARE_COMPLETION_ONSTACK(comp);
183 *
184 *		pdev = kunit_platform_device_alloc(test, "kunit-platform", -1);
185 *		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
186 *		KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_add(test, pdev));
187 *
188 *		pdrv = kunit_kzalloc(test, sizeof(*pdrv), GFP_KERNEL);
189 *		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdrv);
190 *
191 *		pdrv->probe = kunit_platform_driver_probe;
192 *		pdrv->driver.name = "kunit-platform";
193 *		pdrv->driver.owner = THIS_MODULE;
194 *
195 *		KUNIT_ASSERT_EQ(test, 0, kunit_platform_device_prepare_wait_for_probe(test, pdev, &comp));
196 *		KUNIT_ASSERT_EQ(test, 0, kunit_platform_driver_register(test, pdrv));
197 *
198 *		KUNIT_EXPECT_NE(test, 0, wait_for_completion_timeout(&comp, 3 * HZ));
199 *	}
200 *
201 * Return: 0 on success, negative errno on failure.
202 */
203int kunit_platform_device_prepare_wait_for_probe(struct kunit *test,
204						 struct platform_device *pdev,
205						 struct completion *x)
206{
207	struct device *dev = &pdev->dev;
208	struct kunit_platform_device_probe_nb *knb;
209	bool bound;
210
211	knb = kunit_kzalloc(test, sizeof(*knb), GFP_KERNEL);
212	if (!knb)
213		return -ENOMEM;
214
215	knb->nb.notifier_call = kunit_platform_device_probe_notify;
216	knb->dev = dev;
217	knb->x = x;
218
219	device_lock(dev);
220	bound = device_is_bound(dev);
221	if (bound) {
222		device_unlock(dev);
223		complete(x);
224		kunit_kfree(test, knb);
225		return 0;
226	}
227
228	bus_register_notifier(&platform_bus_type, &knb->nb);
229	device_unlock(&pdev->dev);
230
231	return kunit_add_action_or_reset(test, kunit_platform_device_probe_nb_remove, &knb->nb);
232}
233EXPORT_SYMBOL_GPL(kunit_platform_device_prepare_wait_for_probe);
234
235KUNIT_DEFINE_ACTION_WRAPPER(platform_driver_unregister_wrapper,
236			    platform_driver_unregister, struct platform_driver *);
237/**
238 * kunit_platform_driver_register() - Register a KUnit test managed platform driver
239 * @test: test context
240 * @drv: platform driver to register
241 *
242 * Register a test managed platform driver. This allows callers to embed the
243 * @drv in a container structure and use container_of() in the probe function
244 * to pass information to KUnit tests.
245 *
246 * Example
247 *
248 * .. code-block:: c
249 *
250 *	struct kunit_test_context {
251 *		struct platform_driver pdrv;
252 *		const char *data;
253 *	};
254 *
255 *	static inline struct kunit_test_context *
256 *	to_test_context(struct platform_device *pdev)
257 *	{
258 *		return container_of(to_platform_driver(pdev->dev.driver),
259 *				    struct kunit_test_context,
260 *				    pdrv);
261 *	}
262 *
263 *	static int kunit_platform_driver_probe(struct platform_device *pdev)
264 *	{
265 *		struct kunit_test_context *ctx;
266 *
267 *		ctx = to_test_context(pdev);
268 *		ctx->data = "test data";
269 *
270 *		return 0;
271 *	}
272 *
273 *	static void kunit_platform_driver_test(struct kunit *test)
274 *	{
275 *		struct kunit_test_context *ctx;
276 *
277 *		ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
278 *		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);
279 *
280 *		ctx->pdrv.probe = kunit_platform_driver_probe;
281 *		ctx->pdrv.driver.name = "kunit-platform";
282 *		ctx->pdrv.driver.owner = THIS_MODULE;
283 *
284 *		KUNIT_EXPECT_EQ(test, 0, kunit_platform_driver_register(test, &ctx->pdrv));
285 *		<... wait for driver to probe ...>
286 *		KUNIT_EXPECT_STREQ(test, ctx->data, "test data");
287 *	}
288 *
289 * Return: 0 on success, negative errno on failure.
290 */
291int kunit_platform_driver_register(struct kunit *test,
292				   struct platform_driver *drv)
293{
294	int ret;
295
296	ret = platform_driver_register(drv);
297	if (ret)
298		return ret;
299
300	return kunit_add_action_or_reset(test, platform_driver_unregister_wrapper, drv);
301}
302EXPORT_SYMBOL_GPL(kunit_platform_driver_register);