/*
 * Copyright (C) 2010-2015 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 licence.
 * 
 * A copy of the licence is included with the program, and can also be obtained from Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

/**
 * @file mali_osk_irq.c
 * Implementation of the OS abstraction layer for the kernel device driver
 */

#include <linux/slab.h> /* For memory allocation */
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/sched.h>

#include "mali_osk.h"
#include "mali_kernel_common.h"

typedef struct _mali_osk_irq_t_struct {
        u32 irqnum;
        void *data;
        _mali_osk_irq_uhandler_t uhandler;
} mali_osk_irq_object_t;

typedef irqreturn_t (*irq_handler_func_t)(int, void *, struct pt_regs *);
static irqreturn_t irq_handler_upper_half(int port_name, void *dev_id);   /* , struct pt_regs *regs*/

#if defined(DEBUG)

struct test_interrupt_data {
        _mali_osk_irq_ack_t ack_func;
        void *probe_data;
        mali_bool interrupt_received;
        wait_queue_head_t wq;
};

static irqreturn_t test_interrupt_upper_half(int port_name, void *dev_id)
{
        irqreturn_t ret = IRQ_NONE;
        struct test_interrupt_data *data = (struct test_interrupt_data *)dev_id;

        if (_MALI_OSK_ERR_OK == data->ack_func(data->probe_data)) {
                data->interrupt_received = MALI_TRUE;
                wake_up(&data->wq);
                ret = IRQ_HANDLED;
        }

        return ret;
}

static _mali_osk_errcode_t test_interrupt(u32 irqnum,
                _mali_osk_irq_trigger_t trigger_func,
                _mali_osk_irq_ack_t ack_func,
                void *probe_data,
                const char *description)
{
        unsigned long irq_flags = 0;
        struct test_interrupt_data data = {
                .ack_func = ack_func,
                .probe_data = probe_data,
                .interrupt_received = MALI_FALSE,
        };

#if defined(CONFIG_MALI_SHARED_INTERRUPTS)
        irq_flags |= IRQF_SHARED;
#endif /* defined(CONFIG_MALI_SHARED_INTERRUPTS) */

        if (0 != request_irq(irqnum, test_interrupt_upper_half, irq_flags, description, &data)) {
                MALI_DEBUG_PRINT(2, ("Unable to install test IRQ handler for core '%s'\n", description));
                return _MALI_OSK_ERR_FAULT;
        }

        init_waitqueue_head(&data.wq);

        trigger_func(probe_data);
        wait_event_timeout(data.wq, data.interrupt_received, 100);

        free_irq(irqnum, &data);

        if (data.interrupt_received) {
                MALI_DEBUG_PRINT(3, ("%s: Interrupt test OK\n", description));
                return _MALI_OSK_ERR_OK;
        } else {
                MALI_PRINT_ERROR(("%s: Failed interrupt test on %u\n", description, irqnum));
                return _MALI_OSK_ERR_FAULT;
        }
}

#endif /* defined(DEBUG) */

_mali_osk_irq_t *_mali_osk_irq_init(u32 irqnum, _mali_osk_irq_uhandler_t uhandler, void *int_data, _mali_osk_irq_trigger_t trigger_func, _mali_osk_irq_ack_t ack_func, void *probe_data, const char *description)
{
        mali_osk_irq_object_t *irq_object;
        unsigned long irq_flags = 0;

#if defined(CONFIG_MALI_SHARED_INTERRUPTS)
        irq_flags |= IRQF_SHARED;
#endif /* defined(CONFIG_MALI_SHARED_INTERRUPTS) */

        irq_object = kmalloc(sizeof(mali_osk_irq_object_t), GFP_KERNEL);
        if (NULL == irq_object) {
                return NULL;
        }

        if (-1 == irqnum) {
                /* Probe for IRQ */
                if ((NULL != trigger_func) && (NULL != ack_func)) {
                        unsigned long probe_count = 3;
                        _mali_osk_errcode_t err;
                        int irq;

                        MALI_DEBUG_PRINT(2, ("Probing for irq\n"));

                        do {
                                unsigned long mask;

                                mask = probe_irq_on();
                                trigger_func(probe_data);

                                _mali_osk_time_ubusydelay(5);

                                irq = probe_irq_off(mask);
                                err = ack_func(probe_data);
                        } while (irq < 0 && (err == _MALI_OSK_ERR_OK) && probe_count--);

                        if (irq < 0 || (_MALI_OSK_ERR_OK != err)) irqnum = -1;
                        else irqnum = irq;
                } else irqnum = -1; /* no probe functions, fault */

                if (-1 != irqnum) {
                        /* found an irq */
                        MALI_DEBUG_PRINT(2, ("Found irq %d\n", irqnum));
                } else {
                        MALI_DEBUG_PRINT(2, ("Probe for irq failed\n"));
                }
        }

        irq_object->irqnum = irqnum;
        irq_object->uhandler = uhandler;
        irq_object->data = int_data;

        if (-1 == irqnum) {
                MALI_DEBUG_PRINT(2, ("No IRQ for core '%s' found during probe\n", description));
                kfree(irq_object);
                return NULL;
        }

#if defined(DEBUG)
        /* Verify that the configured interrupt settings are working */
        if (_MALI_OSK_ERR_OK != test_interrupt(irqnum, trigger_func, ack_func, probe_data, description)) {
                MALI_DEBUG_PRINT(2, ("Test of IRQ handler for core '%s' failed\n", description));
                kfree(irq_object);
                return NULL;
        }
#endif

        if (0 != request_irq(irqnum, irq_handler_upper_half, irq_flags, description, irq_object)) {
                MALI_DEBUG_PRINT(2, ("Unable to install IRQ handler for core '%s'\n", description));
                kfree(irq_object);
                return NULL;
        }

        return irq_object;
}

void _mali_osk_irq_term(_mali_osk_irq_t *irq)
{
        mali_osk_irq_object_t *irq_object = (mali_osk_irq_object_t *)irq;
        free_irq(irq_object->irqnum, irq_object);
        kfree(irq_object);
}


/** This function is called directly in interrupt context from the OS just after
 * the CPU get the hw-irq from mali, or other devices on the same IRQ-channel.
 * It is registered one of these function for each mali core. When an interrupt
 * arrives this function will be called equal times as registered mali cores.
 * That means that we only check one mali core in one function call, and the
 * core we check for each turn is given by the \a dev_id variable.
 * If we detect an pending interrupt on the given core, we mask the interrupt
 * out by settging the core's IRQ_MASK register to zero.
 * Then we schedule the mali_core_irq_handler_bottom_half to run as high priority
 * work queue job.
 */
static irqreturn_t irq_handler_upper_half(int port_name, void *dev_id)   /* , struct pt_regs *regs*/
{
        irqreturn_t ret = IRQ_NONE;
        mali_osk_irq_object_t *irq_object = (mali_osk_irq_object_t *)dev_id;

        if (_MALI_OSK_ERR_OK == irq_object->uhandler(irq_object->data)) {
                ret = IRQ_HANDLED;
        }

        return ret;
}