// SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
/*
 *
 * (C) COPYRIGHT 2016-2023 ARM Limited. All rights reserved.
 *
 * This program is free software and is provided to you under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation, and any use by you of this program is subject to the terms
 * of such GNU license.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you can access it online at
 * http://www.gnu.org/licenses/gpl-2.0.html.
 *
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/interrupt.h>

#include "mali_kbase.h"
#include <device/mali_kbase_device.h>
#include <backend/gpu/mali_kbase_pm_internal.h>
#include <backend/gpu/mali_kbase_irq_internal.h>

#include <kutf/kutf_suite.h>
#include <kutf/kutf_utils.h>

/*
 * This file contains the code which is used for measuring interrupt latency
 * of the Mali GPU IRQ. In particular, function mali_kutf_irq_latency() is
 * used with this purpose and it is called within KUTF framework - a kernel
 * unit test framework. The measured latency provided by this test should
 * be representative for the latency of the Mali JOB/MMU IRQs as well.
 */

/* KUTF test application pointer for this test */
static struct kutf_application *irq_app;

/**
 * struct kutf_irq_fixture_data - test fixture used by the test functions.
 * @kbdev:	kbase device for the GPU.
 *
 */
struct kutf_irq_fixture_data {
	struct kbase_device *kbdev;
};

/* Tag for GPU IRQ */
#define GPU_IRQ_TAG 2

#define NR_TEST_IRQS ((u32)1000000)

#define IRQ_TIMEOUT HZ

static void *kbase_untag(void *ptr)
{
	return (void *)(((uintptr_t)ptr) & ~(uintptr_t)3);
}

static DECLARE_WAIT_QUEUE_HEAD(wait);
static bool triggered;
static u64 irq_time;

/**
 * kbase_gpu_irq_custom_handler - Custom IRQ throttle handler
 * @irq:  IRQ number
 * @data: Data associated with this IRQ
 *
 * Return: IRQ_HANDLED if any interrupt has been handled. IRQ_NONE otherwise.
 */
static irqreturn_t kbase_gpu_irq_custom_handler(int irq, void *data)
{
	struct kbase_device *kbdev = kbase_untag(data);
	u32 status_reg_enum = GPU_CONTROL_ENUM(GPU_IRQ_STATUS);
	u32 clear_reg_enum = GPU_CONTROL_ENUM(GPU_IRQ_CLEAR);
	u32 test_irq = POWER_CHANGED_SINGLE;
	u32 val = kbase_reg_read32(kbdev, status_reg_enum);
	irqreturn_t result;
	u64 tval;
	bool has_test_irq = val & test_irq;


	if (has_test_irq) {
		tval = ktime_get_real_ns();
		/* Clear the test source only here */
		kbase_reg_write32(kbdev, clear_reg_enum, test_irq);
		/* Remove the test IRQ status bit */
		val = val ^ test_irq;
	}

	if (!val)
		result = IRQ_NONE;
	else {
#if IS_ENABLED(CONFIG_MALI_REAL_HW)
		dev_dbg(kbdev->dev, "%s: irq %d irqstatus 0x%x\n", __func__, irq, val);
		kbase_gpu_interrupt(kbdev, val);
#endif
		result = IRQ_HANDLED;
	}

	if (has_test_irq) {
		irq_time = tval;
		triggered = true;
		wake_up(&wait);
		result = IRQ_HANDLED;
	}

	return result;
}

/**
 * mali_kutf_irq_default_create_fixture() - Creates the fixture data required
 *                                          for all the tests in the irq suite.
 * @context:             KUTF context.
 *
 * Return: Fixture data created on success or NULL on failure
 */
static void *mali_kutf_irq_default_create_fixture(struct kutf_context *context)
{
	struct kutf_irq_fixture_data *data;

	data = kutf_mempool_alloc(&context->fixture_pool, sizeof(struct kutf_irq_fixture_data));

	if (!data)
		goto fail;

	/* Acquire the kbase device */
	data->kbdev = kbase_find_device(-1);
	if (data->kbdev == NULL) {
		kutf_test_fail(context, "Failed to find kbase device");
		goto fail;
	}

	return data;

fail:
	return NULL;
}

/**
 * mali_kutf_irq_default_remove_fixture() - Destroy fixture data previously
 *                          created by mali_kutf_irq_default_create_fixture.
 *
 * @context:             KUTF context.
 */
static void mali_kutf_irq_default_remove_fixture(struct kutf_context *context)
{
	struct kutf_irq_fixture_data *data = context->fixture;
	struct kbase_device *kbdev = data->kbdev;

	kbase_release_device(kbdev);
}

/**
 * mali_kutf_irq_latency() - measure GPU IRQ latency
 * @context:		kutf context within which to perform the test
 *
 * The test triggers IRQs manually, and measures the
 * time between triggering the IRQ and the IRQ handler being executed.
 *
 * This is not a traditional test, in that the pass/fail status has little
 * meaning (other than indicating that the IRQ handler executed at all). Instead
 * the results are in the latencies provided with the test result. There is no
 * meaningful pass/fail result that can be obtained here, instead the latencies
 * are provided for manual analysis only.
 */
static void mali_kutf_irq_latency(struct kutf_context *context)
{
	struct kutf_irq_fixture_data *data = context->fixture;
	struct kbase_device *kbdev = data->kbdev;
	u64 min_time = U64_MAX, max_time = 0, average_time = 0;
	u32 i;
	const char *results;

	/* Force GPU to be powered */
	kbase_pm_context_active(kbdev);
	kbase_pm_wait_for_desired_state(kbdev);

	kbase_set_custom_irq_handler(kbdev, kbase_gpu_irq_custom_handler, GPU_IRQ_TAG);

	for (i = 1; i <= NR_TEST_IRQS; i++) {
		u64 start_time = ktime_get_real_ns();
		u32 reg_enum = GPU_CONTROL_ENUM(GPU_IRQ_RAWSTAT);
		u32 test_irq = POWER_CHANGED_SINGLE;

		triggered = false;

		/* Trigger fake IRQ */
		kbase_reg_write32(kbdev, reg_enum, test_irq);

		if (wait_event_timeout(wait, triggered, IRQ_TIMEOUT) == 0) {
			/* Wait extra time to see if it would come */
			wait_event_timeout(wait, triggered, 10 * IRQ_TIMEOUT);
			break;
		}

		if ((irq_time - start_time) < min_time)
			min_time = irq_time - start_time;
		if ((irq_time - start_time) > max_time)
			max_time = irq_time - start_time;
		average_time += irq_time - start_time;

		udelay(10);
		/* Sleep for a ms, every 10000 iterations, to avoid misleading warning
		 * of CPU softlockup when all GPU IRQs keep going to the same CPU.
		 */
		if (!(i % 10000))
			msleep(1);
	}

	/* Go back to default handler */
	kbase_set_custom_irq_handler(kbdev, NULL, GPU_IRQ_TAG);

	kbase_pm_context_idle(kbdev);

	if (i > NR_TEST_IRQS) {
		do_div(average_time, NR_TEST_IRQS);
		results = kutf_dsprintf(
			&context->fixture_pool,
			"Min latency = %lldns, Max latency = %lldns, Average latency = %lldns\n",
			min_time, max_time, average_time);
		kutf_test_pass(context, results);
	} else {
		results = kutf_dsprintf(
			&context->fixture_pool,
			"Timed out for the %u-th IRQ (loop_limit: %u), triggered late: %d\n", i,
			NR_TEST_IRQS, triggered);
		kutf_test_fail(context, results);
	}
}

/**
 * mali_kutf_irq_test_main_init - Module entry point for this test.
 *
 * Return: 0 on success, error code otherwise
 */
static int __init mali_kutf_irq_test_main_init(void)
{
	struct kutf_suite *suite;

	irq_app = kutf_create_application("irq");

	if (irq_app == NULL) {
		pr_warn("Creation of test application failed!\n");
		return -ENOMEM;
	}

	suite = kutf_create_suite(irq_app, "irq_default", 1, mali_kutf_irq_default_create_fixture,
				  mali_kutf_irq_default_remove_fixture);

	if (suite == NULL) {
		pr_warn("Creation of test suite failed!\n");
		kutf_destroy_application(irq_app);
		return -ENOMEM;
	}

	kutf_add_test(suite, 0x0, "irq_latency", mali_kutf_irq_latency);
	return 0;
}

/**
 * mali_kutf_irq_test_main_exit - Module exit point for this test.
 */
static void __exit mali_kutf_irq_test_main_exit(void)
{
	kutf_destroy_application(irq_app);
}

module_init(mali_kutf_irq_test_main_init);
module_exit(mali_kutf_irq_test_main_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("ARM Ltd.");
MODULE_VERSION("1.0");