ROSE/disk.c

194 lines
6.1 KiB
C
Raw Normal View History

#include "v86defs.h"
#include "print.h"
#include "dosfs/dosfs.h"
#include "stdint.h"
extern void *memcpy(void *restrict dest, const void *restrict src, uintptr_t n);
#define DISKCACHEBLOCKSIZE 0x1000 // 512 * 4
#define DISKCACHESECTORMASK 7
#define DISKCACHESECTORSIZE 8
#define DISKCACHEBLOCKCOUNT 128
uint8_t (*DiskCache)[DISKCACHEBLOCKCOUNT][DISKCACHEBLOCKSIZE] = (uint8_t (*)[DISKCACHEBLOCKCOUNT][DISKCACHEBLOCKSIZE])0x280000;
uint32_t DiskCacheLastRead[DISKCACHEBLOCKCOUNT];
uint32_t DiskCacheSector[DISKCACHEBLOCKCOUNT];
2023-02-10 01:06:42 -06:00
extern uint32_t _gpf_eax_save;
extern uint32_t _gpf_eflags_save;
extern uint16_t error_screen[80*50]; // defined in kernel.c
__attribute((__no_caller_saved_registers__))
extern void error_environment(); // defined in kernel.c
uint32_t numHead;
uint32_t secPerTrack;
uint32_t maxCylinder;
char useCHS = -1;
2023-02-10 01:06:42 -06:00
// TODO This function also inits cache, make that go somewhere else
void Disk_SetupCHS() {
union V86Regs_t regs;
// Check for INT 13 Extensions support
regs.h.ah = 0x41;
regs.w.bx = 0x55AA;
regs.h.dl = 0x80;
V8086Int(0x13, &regs);
// LBA supported if CF clear
if (!(_gpf_eflags_save & 0x1)) {
useCHS = 0;
} else {
FARPTR v86_entry = i386LinearToFp(v86DiskGetGeometry);
enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
// check CF for error
if (_gpf_eflags_save & 0x1) {
uint16_t *vga = error_screen;
vga += printStr("Could not get Disk Geometry.", vga);
error_environment();
for(;;);
}
numHead = ((_gpf_eax_save & 0xff00) >> 8) + 1;
secPerTrack = _gpf_eax_save & 0x3f;
maxCylinder = ((_gpf_eax_save & 0xff0000) >> 16) | ((_gpf_eax_save & 0xc0) << 2);
useCHS = 1;
}
2023-02-10 01:06:42 -06:00
// Init Cache
for (int i = 0; i < DISKCACHEBLOCKCOUNT; i++) {
2023-02-10 01:06:42 -06:00
DiskCacheLastRead[i] = 0;
DiskCacheSector[i] = -1;
}
}
extern uint32_t TIMERVAL;
uint8_t *FindInCache(uint32_t sector) {
uint32_t maskedSector = sector & ~DISKCACHESECTORMASK;
for (int i = 0; i < DISKCACHEBLOCKCOUNT; i++) {
2023-02-10 01:06:42 -06:00
// Found
if (DiskCacheSector[i] == maskedSector) {
DiskCacheLastRead[i] = TIMERVAL;
return &(*DiskCache)[i][(sector & DISKCACHESECTORMASK) << 9];
2023-02-10 01:06:42 -06:00
}
}
// Not Found
return 0;
}
void AddToCache(uint32_t sector, uint8_t *buffer) {
uintptr_t lowestFoundTime = DiskCacheLastRead[0];
uintptr_t lowestFoundIdx = 0;
// TODO We should really use something more fast and less lazy
for (int i = 1; i < DISKCACHEBLOCKCOUNT; i++) {
2023-02-10 01:06:42 -06:00
if (DiskCacheLastRead[i] < lowestFoundTime) {
lowestFoundTime = DiskCacheLastRead[i];
lowestFoundIdx = i;
}
}
for (int i = 0; i < DISKCACHEBLOCKSIZE / sizeof(uint32_t); i++)
2023-02-10 01:06:42 -06:00
((uint32_t *)((*DiskCache)[lowestFoundIdx]))[i] = ((uint32_t*)buffer)[i];
DiskCacheLastRead[lowestFoundIdx] = TIMERVAL;
DiskCacheSector[lowestFoundIdx] = sector;
}
2023-02-10 01:06:42 -06:00
// NOTE Only updates one sector (512B)
void UpdateCache(uint32_t sector, uint8_t *buffer) {
uint8_t *cache = FindInCache(sector);
// Not in cache, nothing to update
if (!cache) return;
for (int i = 0; i < SECTOR_SIZE/sizeof(uint32_t); i++)
((uint32_t*)cache)[i] = ((uint32_t*)buffer)[i];
}
uint32_t DFS_ReadSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count) {
// NOTE If the buffer provided is outside the 0x20000-0x2FE00 range,
// the function will use that buffer for the Virtual 8086 process
// and copy to the other buffer after
uint8_t *v86buf = buffer;
2023-02-10 01:06:42 -06:00
if ((uintptr_t)v86buf >= 0x20000 && (uintptr_t)v86buf < 0x28000)
v86buf = (uint8_t *)0x28000;
else v86buf = (uint8_t *)0x20000;
// TODO This check should probably happen at the kernel level
if (useCHS == -1) {
Disk_SetupCHS();
}
2023-02-10 01:06:42 -06:00
uint8_t *cache = FindInCache(sector);
if (cache) {
memcpy(buffer, cache, count * SECTOR_SIZE);
return 0;
}
// TODO Do error handling
if (!useCHS) {
// LBA Read
v86disk_addr_packet.start_block = sector & ~DISKCACHESECTORMASK;
v86disk_addr_packet.blocks = DISKCACHESECTORSIZE;
v86disk_addr_packet.transfer_buffer =
(uintptr_t)v86buf & 0x000F |
(((uintptr_t)v86buf & 0xFFFF0) << 12);
union V86Regs_t regs;
regs.h.ah = 0x42;
FARPTR v86_entry = i386LinearToFp(v86DiskOp);
enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
if (v86disk_addr_packet.blocks != DISKCACHESECTORSIZE) {
2023-02-10 01:06:42 -06:00
uint16_t *vga = error_screen;
vga += printStr("INT13 Read Secs: ", vga);
vga += printDec(v86disk_addr_packet.blocks, vga);
error_environment();
for(;;);
}
AddToCache(sector & ~DISKCACHESECTORMASK, v86buf);
v86buf = &v86buf[(sector & DISKCACHESECTORMASK) << 9];
} else {
uint32_t tmp = sector / secPerTrack;
uint32_t sec = (sector % (secPerTrack)) + 1;
uint32_t head = tmp % numHead;
uint32_t cyl = tmp / numHead;
union V86Regs_t regs;
regs.w.ax = 0x0201;
regs.h.ch = cyl & 0xff;
regs.h.cl = sec | ((cyl >> 2) & 0xc0);
regs.h.dh = head;
regs.h.dl = 0x80;
regs.w.bx = (uintptr_t)v86buf & 0xFFFF;
FARPTR v86_entry = i386LinearToFp(v86DiskReadCHS);
enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
}
if (v86buf != buffer)
memcpy(buffer, v86buf, count * SECTOR_SIZE);
return 0;
}
uint32_t DFS_WriteSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count) {
// NOTE If the buffer provided is outside the 0x20000-0x2FE00 range,
// the function will use copy that buffer into the Virtual 8086 disk range
uint8_t *v86buf = buffer;
if ((uintptr_t)v86buf < 0x20000 || (uintptr_t)v86buf > 0x2FE00) {
v86buf = (uint8_t *)0x20000;
memcpy(v86buf, buffer, count * SECTOR_SIZE);
}
// TODO This check should probably happen at the kernel level
if (useCHS == -1) {
Disk_SetupCHS();
}
// TODO Do error handling
if (!useCHS) {
2023-02-09 23:32:51 -06:00
// LBA Write
v86disk_addr_packet.start_block = sector;
v86disk_addr_packet.blocks = count;
v86disk_addr_packet.transfer_buffer =
(uintptr_t)v86buf & 0x000F |
(((uintptr_t)v86buf & 0xFFFF0) << 12);
union V86Regs_t regs;
regs.w.ax = 0x4300;
FARPTR v86_entry = i386LinearToFp(v86DiskOp);
enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
2023-02-10 01:06:42 -06:00
UpdateCache(sector, buffer);
} else {
uint16_t *vga = error_screen;
vga += printStr("CHS Write Unimplemented", vga);
error_environment();
for(;;);
}
return 0;
}