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/*

 * Copyright (c) 2007 Michal Kebrt, Petr Stepan

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup arm32

 * @{

 */

/** @file

 *  @brief GXemul drivers.

 */

#include <interrupt.h>

#include <ipc/irq.h>

#include <console/chardev.h>

#include <arch/drivers/gxemul.h>

#include <console/console.h>

#include <sysinfo/sysinfo.h>

#include <print.h>

#include <ddi/device.h>

#include <mm/page.h>

#include <arch/machine.h>

#include <arch/debug/print.h>

/** Addresses of devices. */

#define GXEMUL_VIDEORAM            0x10000000

#define GXEMUL_KBD                 0x10000000

#define GXEMUL_HALT_OFFSET         0x10

#define GXEMUL_RTC                 0x15000000

#define GXEMUL_RTC_FREQ_OFFSET     0x100

#define GXEMUL_RTC_ACK_OFFSET      0x110

#define GXEMUL_IRQC                0x16000000

#define GXEMUL_IRQC_MASK_OFFSET    0x4

#define GXEMUL_IRQC_UNMASK_OFFSET  0x8

#define GXEMUL_MP                  0x11000000

#define GXEMUL_MP_MEMSIZE_OFFSET   0x0090

#define GXEMUL_FB                  0x12000000

/** IRQs */

#define GXEMUL_KBD_IRQ      2

#define GXEMUL_TIMER_IRQ    4

static gxemul_hw_map_t gxemul_hw_map;

static chardev_t console;

static irq_t gxemul_irq;

static irq_t gxemul_timer_irq;

static bool hw_map_init_called = false;

static void gxemul_write(chardev_t *dev, const char ch);

static void gxemul_enable(chardev_t *dev);

static void gxemul_disable(chardev_t *dev);

static char gxemul_do_read(chardev_t *dev);

static chardev_operations_t gxemul_ops = {

    .resume = gxemul_enable,

    .suspend = gxemul_disable,

    .write = gxemul_write,

    .read = gxemul_do_read,

};

/** Returns the mask of active interrupts. */

static inline uint32_t gxemul_irqc_get_sources(void)

{

    return *(uint32_t*) gxemul_hw_map.irqc;

}

/** Masks interrupt.

 *

 * @param irq interrupt number

 */

static inline void gxemul_irqc_mask(uint32_t irq)

{

    *(uint32_t*) gxemul_hw_map.irqc_mask = irq;

}

/** Unmasks interrupt.

 *

 * @param irq interrupt number

 */

static inline void gxemul_irqc_unmask(uint32_t irq)

{

    *(uint32_t*) gxemul_hw_map.irqc_unmask = irq;

}

/** Initializes #gxemul_hw_map. */

void gxemul_hw_map_init(void)

{

    gxemul_hw_map.videoram = hw_map(GXEMUL_VIDEORAM, PAGE_SIZE);

    gxemul_hw_map.kbd = hw_map(GXEMUL_KBD, PAGE_SIZE);

    gxemul_hw_map.rtc = hw_map(GXEMUL_RTC, PAGE_SIZE);

    gxemul_hw_map.irqc = hw_map(GXEMUL_IRQC, PAGE_SIZE);

    gxemul_hw_map.rtc_freq = gxemul_hw_map.rtc + GXEMUL_RTC_FREQ_OFFSET;

    gxemul_hw_map.rtc_ack = gxemul_hw_map.rtc + GXEMUL_RTC_ACK_OFFSET;

    gxemul_hw_map.irqc_mask = gxemul_hw_map.irqc + GXEMUL_IRQC_MASK_OFFSET;

    gxemul_hw_map.irqc_unmask = gxemul_hw_map.irqc + GXEMUL_IRQC_UNMASK_OFFSET;

    hw_map_init_called = true;

}

/** Putchar that works with gxemul */

static void gxemul_write(chardev_t *dev, const char ch)

{

    *((char *) gxemul_hw_map.videoram) = ch;

}

/* Called from getc(). */

static void gxemul_enable(chardev_t *dev)

{

    gxemul_irqc_unmask(GXEMUL_KBD_IRQ);

}

/* Called from getc(). */

static void gxemul_disable(chardev_t *dev)

{

    gxemul_irqc_mask(GXEMUL_KBD_IRQ);

}

/** Read character using polling, assume interrupts disabled.

 *

 *  @param dev Not used.

 */

static char gxemul_do_read(chardev_t *dev)

{

    char ch;

    while (1) {

        ch = *((volatile char *) gxemul_hw_map.kbd);

        if (ch) {

            if (ch == '\r')

                return '\n';

            if (ch == 0x7f)

                return '\b';

            return ch;

        }

    }

}

/** Process keyboard interrupt. */

static void gxemul_irq_handler(irq_t *irq, void *arg, ...)

{

    if ((irq->notif_cfg.notify) && (irq->notif_cfg.answerbox)) {

        ipc_irq_send_notif(irq);

    } else {

        char ch = 0;

        ch = *((char *) gxemul_hw_map.kbd);

        if (ch == '\r') {

            ch = '\n';

        }

        if (ch == 0x7f) {

            ch = '\b';

        }

        chardev_push_character(&console, ch);

    }

}

static irq_ownership_t gxemul_claim(void)

{

    return IRQ_ACCEPT;

}

/** Acquire console back for kernel. */

void gxemul_grab_console(void)

{

    ipl_t ipl = interrupts_disable();

    spinlock_lock(&gxemul_irq.lock);

    gxemul_irq.notif_cfg.notify = false;

    spinlock_unlock(&gxemul_irq.lock);

    interrupts_restore(ipl);

}

/** Return console to userspace. */

void gxemul_release_console(void)

{

    ipl_t ipl = interrupts_disable();

    spinlock_lock(&gxemul_irq.lock);

    if (gxemul_irq.notif_cfg.answerbox) {

        gxemul_irq.notif_cfg.notify = true;

    }

    spinlock_unlock(&gxemul_irq.lock);

    interrupts_restore(ipl);

}

/** Initializes console object representing gxemul console.

 *

 *  @param Console device number.

 */

void gxemul_console_init(devno_t devno)

{

    chardev_initialize("gxemul_console", &console, &gxemul_ops);

    stdin = &console;

    stdout = &console;

    irq_initialize(&gxemul_irq);

    gxemul_irq.devno = devno;

    gxemul_irq.inr = GXEMUL_KBD_IRQ;

    gxemul_irq.claim = gxemul_claim;

    gxemul_irq.handler = gxemul_irq_handler;

    irq_register(&gxemul_irq);

    gxemul_irqc_unmask(GXEMUL_KBD_IRQ);

    sysinfo_set_item_val("kbd", NULL, true);

    sysinfo_set_item_val("kbd.devno", NULL, devno);

    sysinfo_set_item_val("kbd.inr", NULL, GXEMUL_KBD_IRQ);

    sysinfo_set_item_val("kbd.address.virtual", NULL, gxemul_hw_map.kbd);

}

/** Starts gxemul Real Time Clock device, which asserts regular interrupts.

 *

 * @param frequency Interrupts frequency (0 disables RTC).

 */

static void gxemul_timer_start(uint32_t frequency)

{

    *(uint32_t*) gxemul_hw_map.rtc_freq = frequency;

}

static irq_ownership_t gxemul_timer_claim(void)

{

    return IRQ_ACCEPT;

}

/** Timer interrupt handler.

 *

 * @param irq Interrupt information.

 * @param arg Not used.

 */

static void gxemul_timer_irq_handler(irq_t *irq, void *arg, ...)

{

    /* TODO time drifts ??

    unsigned long drift;

    drift = cp0_count_read() - nextcount;

    while (drift > cp0_compare_value) {

        drift -= cp0_compare_value;

        CPU->missed_clock_ticks++;

    }

    nextcount = cp0_count_read() + cp0_compare_value - drift;

    cp0_compare_write(nextcount);

    */

    /*

    * We are holding a lock which prevents preemption.

    * Release the lock, call clock() and reacquire the lock again.

    */

    spinlock_unlock(&irq->lock);

    clock();

    spinlock_lock(&irq->lock);

    /* acknowledge tick */

    *(uint32_t*) gxemul_hw_map.rtc_ack = 0;

    /* TODO what's that? *

    if (virtual_timer_fnc != NULL)

        virtual_timer_fnc();

    */

}

/** Initializes and registers timer interrupt handler. */

static void gxemul_timer_irq_init()

{

    irq_initialize(&gxemul_timer_irq);

    gxemul_timer_irq.devno = device_assign_devno();

    gxemul_timer_irq.inr = GXEMUL_TIMER_IRQ;

    gxemul_timer_irq.claim = gxemul_timer_claim;

    gxemul_timer_irq.handler = gxemul_timer_irq_handler;

    irq_register(&gxemul_timer_irq);

}

/** Starts timer.

 *

 * Initiates regular timer interrupts after initializing

 * corresponding interrupt handler.

 */

void gxemul_timer_irq_start()

{

    gxemul_timer_irq_init();

    gxemul_timer_start(GXEMUL_TIMER_FREQ);

}

/** Returns the size of emulated memory.

 *

 * @return Size in bytes.

 */

size_t gxemul_get_memory_size(void)

{

    return  *((int*)(GXEMUL_MP + GXEMUL_MP_MEMSIZE_OFFSET));

}

/** Prints a character.

 *

 *  @param ch Character to be printed.

 */

void gxemul_debug_putc(char ch)

{

    char * addr = 0;

    if (!hw_map_init_called) {

        addr = (char *) GXEMUL_KBD;

    } else {

        addr = (char *) gxemul_hw_map.videoram;

    }

    *(addr) = ch;

}

/** Stops gxemul. */

void gxemul_cpu_halt(void)

{

    char * addr = 0;

    if (!hw_map_init_called) {

        addr = (char *) GXEMUL_KBD;

    } else {

        addr = (char *) gxemul_hw_map.videoram;

    }

    *(addr + GXEMUL_HALT_OFFSET) = '\0';

}

/** Gxemul specific interrupt exception handler.

 *

 * Determines sources of the interrupt from interrupt controller and

 * calls high-level handlers for them.

 *

 * @param exc_no Interrupt exception number.

 * @param istate Saved processor state.

 */

void gxemul_irq_exception(int exc_no, istate_t *istate)

{

    uint32_t sources = gxemul_irqc_get_sources();

    int i = 0;

    for (; i < GXEMUL_IRQC_MAX_IRQ; i++) {

        if (sources & (1 << i)) {

            irq_t *irq = irq_dispatch_and_lock(i);

            if (irq) {

                /* The IRQ handler was found. */

                irq->handler(irq, irq->arg);

                spinlock_unlock(&irq->lock);

            } else {

                /* Spurious interrupt.*/

                dprintf("cpu%d: spurious interrupt (inum=%d)\n", CPU->id, i);

            }

        }

    }

}

/** Returns address of framebuffer device.

 *

 *  @return Address of framebuffer device.

 */

uintptr_t gxemul_get_fb_address(void)

{

    return (uintptr_t) GXEMUL_FB;

}

/** @}

 */