#include <stdio.h>
#include <mint/osbind.h>
#include <stdint.h>
#include <stdbool.h>

#include "driver_vec.h"

struct driver_table *get_bas_drivers(void)
{
    struct driver_table *ret = NULL;

    __asm__ __volatile__(
        "           bra.s   do_trap             \n\t"
        "           .dc.l   0x5f424153          \n\t"   // '_BAS'
        "do_trap:   trap    #0                  \n\t"
        "           move.l  d0,%[ret]           \n\t"
        :   [ret] "=m" (ret)    /* output */
        :                       /* no inputs */
        :                       /* clobbered */
    );

    return ret;
}

/*
 * temporarily replace the trap 0 handler with this so we can avoid
 * getting caught by BaS versions that don't understand the driver interface
 * exposure call.
 * If we get here, we have a BaS version that doesn't support the trap 0 interface
 */
static void __attribute__((interrupt)) trap0_catcher(void)
{
    __asm__ __volatile__(
        "       clr.l       d0              \n\t"       // return 0 to indicate not supported
        :
        :
        :
    );
}

static uint32_t cookieptr(void)
{
    return * (uint32_t *) 0x5a0L;
}

void setcookie(uint32_t cookie, uint32_t value)
{
    uint32_t *cookiejar = (uint32_t *) Supexec(cookieptr);
    int num_slots;
    int max_slots;

    num_slots = max_slots = 0;
    do
    {
        if (cookiejar[0] == cookie)
        {
            cookiejar[1] = value;
            return;
        }
        cookiejar = &(cookiejar[2]);
        num_slots++;
    } while (cookiejar[-2]);

    /*
     * Here we are at the end of the list and did not find our cookie.
     * Let's check if there is any space left and append our value to the
     * list if so. If not, we are lost (extending the cookie jar does only
     * work from TSRs)
     */
    if (cookiejar[-1])
    {
        max_slots = cookiejar[-1];
    }

    if (max_slots > num_slots)
    {
         /* relief, there is space left, extend the list */
        cookiejar[0] = cookiejar[-2];
        cookiejar[1] = cookiejar[-1];
        /* add the new element */
        cookiejar[-2] = cookie;
        cookiejar[-1] = value;
    }
    else
        printf("cannot set cookie, cookie jar is full!\r\n");
}

#define COOKIE_DMAC 0x444d4143L /* FireTOS DMA API cookie ("DMAC") */
#define COOKIE_BAS_ 0x4241535fL /* BAS_ cookie (points to driver table struct */

static char *dt_to_str(enum driver_type dt)
{
    switch (dt)
    {
        case BLOCKDEV_DRIVER:   return "generic block device driver";
        case CHARDEV_DRIVER:    return "generic character device driver";
        case VIDEO_DRIVER:      return "video/framebuffer driver";
        case XHDI_DRIVER:       return "XHDI compatible hard disk driver";
        case MCD_DRIVER:        return "multichannel DMA driver";
        case PCI_DRIVER:        return "PCI interface driver";
        case MMU_DRIVER:        return "MMU lock/unlock pages driver";
        case PCI_NATIVE_DRIVER: return "PCI interface native driver";
        default:                return "unknown driver type";
    }
}

static void set_driver_cookies(void)
{
    struct driver_table *dt;
    void *old_vector;
    char **sysbase = (char **) 0x4f2;
    uint32_t sig;

    sig = * (long *)((*sysbase) + 0x2c);

    /*
     * first check if we are on EmuTOS, FireTOS want's to do everything itself
     */
    if (sig == 0x45544f53)
    {
        old_vector = Setexc(0x20, trap0_catcher);               /* set our own temporarily */
        dt = get_bas_drivers();                                 /* trap #0 */
        (void) Setexc(0x20, old_vector);                        /* restore original vector */

        if (dt)
        {
            struct generic_interface *ifc = &dt->interfaces[0];

            printf("BaS driver table found at %p, BaS version is %d.%d\r\n", dt,
                    dt->bas_version, dt->bas_revision);

            while (ifc->type != END_OF_DRIVERS)
            {
                printf("driver \"%s (%s)\" found,\r\n"
                       "interface type is %d (%s),\r\n"
                       "version %d.%d\r\n\r\n",
                        ifc->name, ifc->description, ifc->type, dt_to_str(ifc->type),
                        ifc->version, ifc->revision);
                if (ifc->type == MCD_DRIVER)
                {
                    setcookie(COOKIE_DMAC, (uint32_t) ifc->interface.dma);
                    printf("\r\nDMAC cookie set to %p\r\n", ifc->interface.dma);
                }
                ifc++;
            }

            /*
             * set cookie to be able to find the driver table later on
             */
            setcookie(COOKIE_BAS_, (uint32_t) dt);
            printf("BAS_ cookie set to %p\r\n", dt);
        }
        else
        {
            printf("driver table not found.\r\n");
        }
    }
    else
    {
        printf("not running on EmuTOS,\r\n(signature 0x%04x instead of 0x%04x\r\n",
               (uint32_t) sig, 0x45544f53);
    }
}

int main(int argc, char *argv[])
{
    (void) Cconws("retrieve BaS driver interface\r\n");

    Supexec(set_driver_cookies);

    while (Cconis()) Cconin();  /* eat keys */

    return 0;
}