Create platform-agnostic memory mapping scheme.

[farlepet]

Potential API:

int mmu_map(uintptr_t virt, uintptr_t phys, size_t size, uint32_t flags);
int mmu_unmap(uintptr_t virt, size_t size);

virt: Virtual address. Rounded down to nearest page boundry
phys: Physical address. Rounded down to nearest page boundry
size: How many bytes to map. Rounded up to the nearest multiple of page size
flags: Flags affecting page mapping

Potential flags values:

#define MMU_FLAG_READ   (0x00000001) /** Mapped memory can be read from */
#define MMU_FLAG_WRITE  (0x00000002) /** Mapped memory can be written to */
#define MMU_FLAG_EXEC   (0x00000004) /** Mapped memory can be executed */
#define MMU_FLAG_KERNEL (0x00000010) /** Mapped memory belongs to the kernel, can cannot be accessed by user processes */

In addition, it may be useful to also create an API that populates (or uses) a handle that can be used to keep track of mapped memory, and unmap it in the future if desired.

typedef struct {
    uintptr_t virt; /** Pointer to start of virtual mapped memory region */
    uintptr_t phys; /** Pointer to start of physical mapped memory region */
    size_t size; /** Size of mapped memory region */
    uint32_t flags; /** Flags */
} mmu_map_entry_t;

/* (Name to be determined) */
int mmu_vmap(mmu_map_entry_t *entry);
int mmu_vunmap(mmu_map_entry_t *entry);

[farlepet]

Closing as initial support is complete.