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// Code for emulating a drive via high-memory accesses.
//
// Copyright (C) 2009 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU LGPLv3 license.
#include "disk.h" // process_ramdisk_op
#include "util.h" // dprintf
#include "memmap.h" // add_e820
#include "biosvar.h" // GET_GLOBAL
#include "bregs.h" // struct bregs
#include "boot.h" // boot_add_floppy
void
ramdisk_setup(void)
{
if (!CONFIG_FLASH_FLOPPY)
return;
// Find image.
struct romfile_s *file = romfile_findprefix("floppyimg/", NULL);
if (!file)
return;
const char *filename = file->name;
u32 size = file->size;
dprintf(3, "Found floppy file %s of size %d\n", filename, size);
int ftype = find_floppy_type(size);
if (ftype < 0) {
dprintf(3, "No floppy type found for ramdisk size\n");
return;
}
// Allocate ram for image.
void *pos = memalign_tmphigh(PAGE_SIZE, size);
if (!pos) {
warn_noalloc();
return;
}
add_e820((u32)pos, size, E820_RESERVED);
// Copy image into ram.
int ret = file->copy(file, pos, size);
if (ret < 0)
return;
// Setup driver.
struct drive_s *drive_g = init_floppy((u32)pos, ftype);
if (!drive_g)
return;
drive_g->type = DTYPE_RAMDISK;
dprintf(1, "Mapping CBFS floppy %s to addr %p\n", filename, pos);
char *desc = znprintf(MAXDESCSIZE, "Ramdisk [%s]", &filename[10]);
boot_add_floppy(drive_g, desc, bootprio_find_named_rom(filename, 0));
}
static int
ramdisk_copy(struct disk_op_s *op, int iswrite)
{
u32 offset = GET_GLOBAL(op->drive_g->cntl_id);
offset += (u32)op->lba * DISK_SECTOR_SIZE;
u64 opd = GDT_DATA | GDT_LIMIT(0xfffff) | GDT_BASE((u32)op->buf_fl);
u64 ramd = GDT_DATA | GDT_LIMIT(0xfffff) | GDT_BASE(offset);
u64 gdt[6];
if (iswrite) {
gdt[2] = opd;
gdt[3] = ramd;
} else {
gdt[2] = ramd;
gdt[3] = opd;
}
// Call int 1587 to copy data.
struct bregs br;
memset(&br, 0, sizeof(br));
br.flags = F_CF|F_IF;
br.ah = 0x87;
br.es = GET_SEG(SS);
br.si = (u32)gdt;
br.cx = op->count * DISK_SECTOR_SIZE / 2;
call16_int(0x15, &br);
if (br.flags & F_CF)
return DISK_RET_EBADTRACK;
return DISK_RET_SUCCESS;
}
int
process_ramdisk_op(struct disk_op_s *op)
{
if (!CONFIG_FLASH_FLOPPY)
return 0;
switch (op->command) {
case CMD_READ:
return ramdisk_copy(op, 0);
case CMD_WRITE:
return ramdisk_copy(op, 1);
case CMD_VERIFY:
case CMD_FORMAT:
case CMD_RESET:
return DISK_RET_SUCCESS;
default:
op->count = 0;
return DISK_RET_EPARAM;
}
}
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