// The OS/K Team licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#include <dv/dev.h>

static_assert(sizeof(dev_t) % 8 == 0, "");

dev_t *devalloc(void)
{
    return calloc(sizeof(dev_t)/sizeof(ulong), sizeof(ulong));
}

void devfree(dev_t *dev)
{
    assert(dev != NULL);

    free(dev);
}

dev_t *devget(ctx_t *ctx, int idx)
{
    if (idx < 0)
        return NULL;

    int i;
    dev_t *dev;

    for (i = 0, dev = ctx->dh; dev && i != idx; dev = dev->next, i++);

    return dev;
}

void devattach(ctx_t *ctx, dev_t *dev)
{
    dev_t *it;

    assert(dev != NULL);

    if (ctx->dh) {
        for (it = ctx->dh; it->next != NULL; it = it->next);
        
        it->next = dev;
    }

    else ctx->dh = dev;
}

int devinit(ctx_t *ctx, dev_t *dev)
{
    if (!dev || dev->state != DEVPWOF)
        return -1;

    if (dev->fpwon)
        dev->fpwon(ctx, dev);

    else dev->state = DEVGOOD;

    if (!(dev->state == DEVPLUG || dev->state == DEVGOOD))
        return -1;

    dev->id = random();

    devattach(ctx, dev);

    return 0;
}

// NEVER detach while some assembly code
// may still be running on the vm!
void devdetach(ctx_t *ctx, dev_t *dev)
{
    dev_t *it;

    assert(dev != NULL);

    if (dev == ctx->dh) {
        ctx->dh = dev->next;
    }

    for (it = ctx->dh; it; it = it->next) {
        if (!it)
            break;
        
        if (it->next == dev) {
            it->next = dev->next;
            break;
        }
    }
}

int devfini(ctx_t *ctx, dev_t *dev)
{
    if (dev->state == DEVPWOF || dev->state == DEVFERR) {
        goto err;
    }

    if (dev->fpwoff)
        dev->fpwoff(ctx, dev);

    else dev->state = DEVPWOF;

    if (dev->state != DEVPWOF)
        goto err;

    devdetach(ctx, dev);
    return 0;

err:
    devdetach(ctx, dev);
    return -1;
}

int devinitall(ctx_t *ctx)
{
    return devinit(ctx, &cpudev);
}

int devfiniall(ctx_t *ctx)
{
    int failed = 0;

    while (ctx->dh)
        if (devfini(ctx, ctx->dh) < 0)
            failed = -1;

    return failed;
}