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/*
 * Copyright (c) 2003 Josef Cejka
 * Copyright (c) 2005 Jakub Jermar
 * 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 genericconsole
 * @{
 */
/** @file
 */

#include <console/console.h>
#include <console/chardev.h>
#include <sysinfo/sysinfo.h>
#include <synch/waitq.h>
#include <synch/spinlock.h>
#include <arch/types.h>
#include <ddi/device.h>
#include <ddi/irq.h>
#include <ddi/ddi.h>
#include <ipc/irq.h>
#include <arch.h>
#include <func.h>
#include <print.h>
#include <atomic.h>

#define KLOG_SIZE PAGE_SIZE
#define KLOG_LATENCY 8

/**< Kernel log cyclic buffer */
static char klog[KLOG_SIZE] __attribute__ ((aligned (PAGE_SIZE)));

/**< Kernel log initialized */
static bool klog_inited = false;
/**< First kernel log characters */
static index_t klog_start = 0;
/**< Number of valid kernel log characters */
static size_t klog_len = 0;
/**< Number of stored (not printed) kernel log characters */
static size_t klog_stored = 0;
/**< Number of stored kernel log characters for uspace */
static size_t klog_uspace = 0;

/**< Kernel log spinlock */
SPINLOCK_INITIALIZE(klog_lock);

/** Physical memory area used for klog buffer */
static parea_t klog_parea;
    
/*
 * For now, we use 0 as INR.
 * However, it is therefore desirable to have architecture specific
 * definition of KLOG_VIRT_INR in the future.
 */
#define KLOG_VIRT_INR   0

static irq_t klog_irq;

static chardev_operations_t null_stdout_ops = {
    .suspend = NULL,
    .resume = NULL,
    .write = NULL,
    .read = NULL
};

chardev_t null_stdout = {
    .name = "null",
    .op = &null_stdout_ops
};

/** Allways refuse IRQ ownership.
 *
 * This is not a real IRQ, so we always decline.
 *
 * @return Always returns IRQ_DECLINE.
 */
static irq_ownership_t klog_claim(void)
{
    return IRQ_DECLINE;
}

/** Standard input character device */
chardev_t *stdin = NULL;
chardev_t *stdout = &null_stdout;

/** Initialize kernel logging facility
 *
 * The shared area contains kernel cyclic buffer. Userspace application may
 * be notified on new data with indication of position and size
 * of the data within the circular buffer.
 */
void klog_init(void)
{
    void *faddr = (void *) KA2PA(klog);
    
    ASSERT((uintptr_t) faddr % FRAME_SIZE == 0);
    ASSERT(KLOG_SIZE % FRAME_SIZE == 0);

    devno_t devno = device_assign_devno();
    
    klog_parea.pbase = (uintptr_t) faddr;
    klog_parea.vbase = (uintptr_t) klog;
    klog_parea.frames = SIZE2FRAMES(KLOG_SIZE);
    klog_parea.cacheable = true;
    ddi_parea_register(&klog_parea);

    sysinfo_set_item_val("klog.faddr", NULL, (unative_t) faddr);
    sysinfo_set_item_val("klog.pages", NULL, SIZE2FRAMES(KLOG_SIZE));
    sysinfo_set_item_val("klog.devno", NULL, devno);
    sysinfo_set_item_val("klog.inr", NULL, KLOG_VIRT_INR);

    irq_initialize(&klog_irq);
    klog_irq.devno = devno;
    klog_irq.inr = KLOG_VIRT_INR;
    klog_irq.claim = klog_claim;
    irq_register(&klog_irq);
    
    spinlock_lock(&klog_lock);
    klog_inited = true;
    spinlock_unlock(&klog_lock);
}

/** Get character from character device. Do not echo character.
 *
 * @param chardev Character device.
 *
 * @return Character read.
 */
uint8_t _getc(chardev_t *chardev)
{
    uint8_t ch;
    ipl_t ipl;

    if (atomic_get(&haltstate)) {
        /* If we are here, we are hopefully on the processor, that 
         * issued the 'halt' command, so proceed to read the character
         * directly from input
         */
        if (chardev->op->read)
            return chardev->op->read(chardev);
        /* no other way of interacting with user, halt */
        if (CPU)
            printf("cpu%u: ", CPU->id);
        else
            printf("cpu: ");
        printf("halted - no kconsole\n");
        cpu_halt();
    }

    waitq_sleep(&chardev->wq);
    ipl = interrupts_disable();
    spinlock_lock(&chardev->lock);
    ch = chardev->buffer[(chardev->index - chardev->counter) % CHARDEV_BUFLEN];
    chardev->counter--;
    spinlock_unlock(&chardev->lock);
    interrupts_restore(ipl);

    chardev->op->resume(chardev);

    return ch;
}

/** Get string from character device.
 *
 * Read characters from character device until first occurrence
 * of newline character.
 *
 * @param chardev Character device.
 * @param buf Buffer where to store string terminated by '\0'.
 * @param buflen Size of the buffer.
 *
 * @return Number of characters read.
 */
count_t gets(chardev_t *chardev, char *buf, size_t buflen)
{
    index_t index = 0;
    char ch;

    while (index < buflen) {
        ch = _getc(chardev);
        if (ch == '\b') {
            if (index > 0) {
                index--;
                /* Space backspace, space */
                putchar('\b');
                putchar(' ');
                putchar('\b');
            }
            continue;
        } 
        putchar(ch);

        if (ch == '\n') { /* end of string => write 0, return */
            buf[index] = '\0';
            return (count_t) index;
        }
        buf[index++] = ch;
    }
    return (count_t) index;
}

/** Get character from device & echo it to screen */
uint8_t getc(chardev_t *chardev)
{
    uint8_t ch;

    ch = _getc(chardev);
    putchar(ch);
    return ch;
}

void klog_update(void)
{
    spinlock_lock(&klog_lock);
    
    if ((klog_inited) && (klog_irq.notif_cfg.notify) && (klog_uspace > 0)) {
        ipc_irq_send_msg_3(&klog_irq, klog_start, klog_len, klog_uspace);
        klog_uspace = 0;
    }
    
    spinlock_unlock(&klog_lock);
}

void putchar(char c)
{
    spinlock_lock(&klog_lock);
    
    if ((klog_stored > 0) && (stdout->op->write)) {
        /* Print charaters stored in kernel log */
        index_t i;
        for (i = klog_len - klog_stored; i < klog_len; i++)
            stdout->op->write(stdout, klog[(klog_start + i) % KLOG_SIZE]);
        klog_stored = 0;
    }
    
    /* Store character in the cyclic kernel log */
    klog[(klog_start + klog_len) % KLOG_SIZE] = c;
    if (klog_len < KLOG_SIZE)
        klog_len++;
    else
        klog_start = (klog_start + 1) % KLOG_SIZE;
    
    if (stdout->op->write)
        stdout->op->write(stdout, c);
    else {
        /* The character is just in the kernel log */
        if (klog_stored < klog_len)
            klog_stored++;
    }
    
    /* The character is stored for uspace */
    if (klog_uspace < klog_len)
        klog_uspace++;
    
    /* Check notify uspace to update */
    bool update;
    if ((klog_uspace > KLOG_LATENCY) || (c == '\n'))
        update = true;
    else
        update = false;
    
    spinlock_unlock(&klog_lock);
    
    if (update)
        klog_update();
}

/** @}
 */