/*
 * Copyright (c) 2026, Chloe M.
 * Provided under the BSD-3 clause.
 *
 * Description:  Virtual memory management
 * Author:       Chloe M.
 */

#include <mm/vm.h>
#include <hal/page.h>
#include <ptdef.h>

/* Use to safely convert page size */
#define PAGE_SIZE(PS)                \
    ((PS) >= NELEM(PageSizeTable))   \
        ? PageSizeTable[PAGESIZE_4K] \
        : PageSizeTable[(PS)]

/* Page size table */
static USIZE PageSizeTable[] = {
    [PAGESIZE_4K] = 0x1000
};

PT_STATUS MmUnmapRange(MMU_VAS *Vas, const MM_RANGE *Range, MMU_PAGESIZE PageSize)
{
    PT_STATUS Status;
    UPTR Off = 0;
    UPTR VirtualBase;
    USIZE Gran;

    if (Vas == NULL || Range == NULL) {
        return STATUS_INVALID_PARAM;
    }

    /* Align down the base addresses */
    VirtualBase = ALIGN_DOWN(Range->VirtualBase, PAGESIZE);
    Gran = PAGE_SIZE(PageSize);

    for (Off = 0; Off < Range->Length; Off += Gran) {
        Status = HalMmuUnmapPage(
            Vas,
            VirtualBase + Off,
            PageSize
        );

        if (PT_ERROR(Status)) {
            return Status;
        }
    }

    return STATUS_SUCCESS;
}

PT_STATUS
MmMapRange(MMU_VAS *Vas, const MM_RANGE *Range, MM_PROT Prot, MMU_PAGESIZE PageSize)
{
    PT_STATUS Status;
    UPTR Off = 0;
    UPTR VirtualBase;
    UPTR PhysicalBase;
    USIZE Gran;

    if (Vas == NULL || Range == NULL) {
        return STATUS_INVALID_PARAM;
    }

    /* Align down the base addresses */
    VirtualBase = ALIGN_DOWN(Range->VirtualBase, PAGESIZE);
    PhysicalBase = ALIGN_DOWN(Range->PhysicalBase, PAGESIZE);
    Gran = PAGE_SIZE(PageSize);

    for (Off = 0; Off < Range->Length; Off += Gran) {
        Status = HalMmuMapPage(
            Vas,
            VirtualBase + Off,
            PhysicalBase + Off,
            Prot,
            PageSize
        );

        if (PT_ERROR(Status)) {
            MmUnmapRange(Vas, Range, PageSize);
            return Status;
        }
    }

    return STATUS_SUCCESS;
}