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Kerenl/Firmware: Add map_ebda and map_bios methods in the original place

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In a previous commit I moved everything into the new subdirectories in
FileSystem/SysFS directory without trying to actually make changes in
the code itself too much. Now it's time to split the code to make it
more readable and understandable, hence this change occurs now.
This commit is contained in:
Liav A 2022-04-22 10:34:15 +03:00 • committed by Andreas Kling
parent 7310a9a641
commit 9c6834698f
8 changed files with 65 additions and 33 deletions
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41
Kernel/Firmware/BIOS.cpp Normal file
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/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Firmware/BIOS.h>
#include <Kernel/Memory/MemoryManager.h>
#include <Kernel/Memory/TypedMapping.h>
namespace Kernel {
ErrorOr<Memory::MappedROM> map_bios()
{
Memory::MappedROM mapping;
mapping.size = 128 * KiB;
mapping.paddr = PhysicalAddress(0xe0000);
auto region_size = TRY(Memory::page_round_up(mapping.size));
mapping.region = TRY(MM.allocate_kernel_region(mapping.paddr, region_size, {}, Memory::Region::Access::Read));
return mapping;
}
ErrorOr<Memory::MappedROM> map_ebda()
{
auto ebda_segment_ptr = TRY(Memory::map_typed<u16>(PhysicalAddress(0x40e)));
PhysicalAddress ebda_paddr(PhysicalAddress(*ebda_segment_ptr).get() << 4);
// The EBDA size is stored in the first byte of the EBDA in 1K units
size_t ebda_size = *TRY(Memory::map_typed<u8>(ebda_paddr));
ebda_size *= 1024;
Memory::MappedROM mapping;
auto region_size = TRY(Memory::page_round_up(ebda_size));
mapping.region = TRY(MM.allocate_kernel_region(ebda_paddr.page_base(), region_size, {}, Memory::Region::Access::Read));
mapping.offset = ebda_paddr.offset_in_page();
mapping.size = ebda_size;
mapping.paddr = ebda_paddr;
return mapping;
}
}