diff options
Diffstat (limited to 'vds.h')
| -rw-r--r-- | vds.h | 162 |
1 files changed, 0 insertions, 162 deletions
@@ -1,162 +0,0 @@ -/* - * VBMouse - Interface to the Virtual DMA Service (VDS) - * Copyright (C) 2022 Javier S. Pedro - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version 2 - * of the License, or (at your option) any later version. - - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. - */ - -#ifndef VDS_H -#define VDS_H - -#include <stdbool.h> -#include <stdint.h> - -typedef unsigned char vdserr; -enum vds_errors { - VDS_SUCCESSFUL = 0, - VDS_REGION_NOT_CONTIGUOUS = 1, - VDS_REGION_NOT_ALIGNED = 2, - VDS_UNABLE_TO_LOCK = 3, - VDS_NO_BUFFER_AVAIL = 4, - VDS_REGION_TOO_LARGE = 5, - VDS_BUFFER_IN_USE = 6, - VDS_INVALID_REGION = 7, - VDS_REGION_NOT_LOCKED = 8, - VDS_TOO_MANY_PAGES = 9, - VDS_INVALID_BUFFER_ID = 0xA, - VDS_BUFFER_BOUNDARY = 0xB, - VDS_INVALID_DMA_CHANNEL = 0xC, - VDS_DISABLE_COUNT_OVRFLOW = 0xD, - VDS_DISABLE_COUNT_UNDFLOW = 0xE, - VDS_NOT_SUPPORTED = 0xF, - VDS_FLAGS_NOT_SUPPORTED = 0x10, -}; - -enum vds_flags { -/* - Bit 1 = Automatically copy to/from buffer - Bit 2 = Disable automatic buffer allocation - Bit 3 = Disable automatic remap feature - Bit 4 = Region must not cross 64K physical alignment boundary - Bit 5 = Region must not cross 128K physical alignment boundary - Bit 6 = Copy page-table for scatter/gather remap - Bit 7 = Allow non-present pages for scatter/gather remap -*/ - VDS_AUTO_COPY_DATA = 1 << 1, - VDS_NO_AUTO_ALLOC = 1 << 2, - VDS_NO_AUTO_REMAP = 1 << 3, - VDS_ALIGN_64K = 1 << 4, - VDS_ALIGN_128K = 1 << 5 -}; - -/** DMA Descriptor structure. Describes a potentially DMA-lockable buffer. */ -typedef _Packed struct VDSDDS -{ - /** Size of this buffer. */ - uint32_t regionSize; - /** Logical/segmented address of this buffer, offset part */ - uint32_t offset; - /** Segment of this buffer. */ - uint16_t segOrSelector; - /** Internal VDS buffer ID. */ - uint16_t bufferId; - /** Physical address of this buffer. */ - uint32_t physicalAddress; -} VDSDDS; - -static bool vds_available(void); -#pragma aux vds_available = \ - "mov ax, 0x40" \ - "mov es, ax" \ - "mov al, es:[0x7B]" \ - "and al, 0x20" \ - "setnz al" \ - __value [al] \ - __modify [ax es] - -/** Locks an already allocated buffer into a physical memory location. - * regionSize, offset and segment must be valid in the DDS, - * while the physical address is returned. */ -static vdserr vds_lock_dma_buffer_region(VDSDDS __far * dds, unsigned char flags); -#pragma aux vds_lock_dma_buffer_region = \ - "stc" \ - "mov ax, 0x8103" \ - "int 0x4B" \ - "jc fail" \ - "mov al, 0" \ - "jmp end" \ - "fail: test al, al" \ - "jnz end" \ - "mov al, 0xFF" /* Force a error code if there was none. */ \ - "end:" \ - __parm [es di] [dx] \ - __value [al] \ - __modify [ax] - -/** Unlocks a locked buffer. */ -static vdserr vds_unlock_dma_buffer_region(VDSDDS __far * dds, unsigned char flags); -#pragma aux vds_unlock_dma_buffer_region = \ - "stc" \ - "mov ax, 0x8104" \ - "int 0x4B" \ - "jc fail" \ - "mov al, 0" \ - "jmp end" \ - "fail: test al, al" \ - "jnz end" \ - "mov al, 0xFF" \ - "end:" \ - __parm [es di] [dx] \ - __value [al] \ - __modify [ax] - -/** Allocates a DMA buffer. - * @param dds regionSize must be valid. - * @return dds Physical_Address, Buffer_ID, and Region_Size - */ -static vdserr vds_request_dma_buffer(VDSDDS __far * dds, unsigned char flags); -#pragma aux vds_request_dma_buffer = \ - "stc" \ - "mov ax, 0x8107" \ - "int 0x4B" \ - "jc fail" \ - "mov al, 0" \ - "jmp end" \ - "fail: test al, al" \ - "jnz end" \ - "mov al, 0xFF" \ - "end:" \ - __parm [es di] [dx] \ - __value [al] \ - __modify [ax] - -/** Frees a DMA buffer. */ -static vdserr vds_release_dma_buffer(VDSDDS __far * dds, unsigned char flags); -#pragma aux vds_release_dma_buffer = \ - "stc" \ - "mov ax, 0x8108" \ - "int 0x4B" \ - "jc fail" \ - "mov al, 0" \ - "jmp end" \ - "fail: test al, al" \ - "jnz end" \ - "mov al, 0xFF" \ - "end:" \ - __parm [es di] [dx] \ - __value [al] \ - __modify [ax] - -#endif |