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/* This file implements the methods of direct physical mapping.
*
* A direct physical mapping is done by accepting the physical
* memory address and range from the caller and allowing direct
* access to it. Most significantly, no physical memory is allocated
* when it's mapped or freed when it's unmapped. E.g. device memory.
*/
#include "vm.h"
#include "proto.h"
#include "region.h"
#include "glo.h"
/* These functions are static so as to not pollute the
* global namespace, and are accessed through their function
* pointers.
*/
static int phys_unreference(struct phys_region *pr);
static int phys_writable(struct phys_region *pr);
static int phys_pagefault(struct vmproc *vmp, struct vir_region *region,
struct phys_region *ph, int write, vfs_callback_t cb, void *state,
int len, int *io);
static int phys_copy(struct vir_region *vr, struct vir_region *newvr);
static int phys_pt_flags(struct vir_region *vr);
struct mem_type mem_type_directphys = {
.name = "physical memory mapping",
.ev_copy = phys_copy,
.ev_unreference = phys_unreference,
.writable = phys_writable,
.ev_pagefault = phys_pagefault,
.pt_flags = phys_pt_flags
};
static int phys_pt_flags(struct vir_region *vr){
#if defined(__arm__)
return ARM_VM_PTE_DEVICE;
#else
return 0;
#endif
}
static int phys_unreference(struct phys_region *pr)
{
return OK;
}
static int phys_pagefault(struct vmproc *vmp, struct vir_region *region,
struct phys_region *ph, int write, vfs_callback_t cb, void *state,
int len, int *io)
{
phys_bytes arg = region->param.phys, phmem;
assert(arg != MAP_NONE);
assert(ph->ph->phys == MAP_NONE);
phmem = arg + ph->offset;
assert(phmem != MAP_NONE);
ph->ph->phys = phmem;
return OK;
}
static int phys_writable(struct phys_region *pr)
{
assert(pr->ph->refcount > 0);
return pr->ph->phys != MAP_NONE;
}
void phys_setphys(struct vir_region *vr, phys_bytes phys)
{
vr->param.phys = phys;
}
static int phys_copy(struct vir_region *vr, struct vir_region *newvr)
{
newvr->param.phys = vr->param.phys;
return OK;
}
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