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/* SPDX-License-Identifier: copyleft-next-0.3.1 */
/* Copyright 2021 - 2022, Kim Kuparinen < kimi.h.kuparinen@gmail.com > */
/**
* @file dmem.c
* Handle device memory, i.e. anything outside the physical RAM.
*
* \todo Handle NUMA.
*/
#include <kmi/assert.h>
#include <kmi/dmem.h>
/** Region before RAM. */
static struct mem_region_root pre_ram = { 0 };
/** Region after RAM. */
static struct mem_region_root post_ram = { 0 };
pm_t __pre_base = 0;
pm_t __pre_top = 0;
pm_t __post_base = 0;
pm_t __post_top = 0;
stat_t init_devmem(pm_t ram_base, pm_t ram_top)
{
pm_t mem_top = (pm_t)-1;
__pre_base = 0;
__pre_top = ram_base - 1;
__post_base = ram_top;
__post_top = mem_top;
size_t pre_pages = __pages(__pre_top);
size_t post_pages = __pages(__post_top) - __pages(__post_base);
init_region(&pre_ram, __pre_base, pre_pages);
init_region(&post_ram, __post_base, post_pages);
return OK;
}
vm_t alloc_devmem(struct tcb *t, pm_t dev_start, size_t bytes, vmflags_t flags)
{
hard_assert(t && is_proc(t), ERR_INVAL);
struct mem_region_root *region = NULL;
if (dev_start < __pre_top)
region = &pre_ram;
else if (dev_start > __post_base)
region = &post_ram;
else
return NULL;
vm_t v = alloc_region(region, bytes, &bytes, flags);
if (!v)
return NULL;
if (map_fixed_region(t->proc.vmem, v, dev_start, bytes, flags)) {
unmap_region(t->proc.vmem, v, bytes);
free_region(region, v);
return NULL;
}
return v;
}
stat_t free_devmem(struct tcb *t, vm_t dev_start)
{
hard_assert(t && is_proc(t), ERR_INVAL);
pm_t dev_paddr = 0;
stat_vpage(t->proc.vmem, dev_start, &dev_paddr, 0, 0);
if (dev_paddr >= __pre_top && dev_paddr <= __post_base)
return ERR_ADDR;
struct mem_region *m = 0;
if (dev_paddr < __pre_top)
m = find_used_region(&pre_ram, dev_start);
else if (dev_paddr > __post_base)
m = find_used_region(&post_ram, dev_start);
if (!m)
return ERR_NF;
vm_t start = __addr(m->start);
vm_t end = __addr(m->end);
size_t size = end - start;
unmap_fixed_region(t->proc.vmem, start, size);
if (dev_paddr < __pre_top)
free_region(&pre_ram, dev_start);
else if (dev_paddr > __post_base)
free_region(&post_ram, dev_start);
return OK;
}
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