blob: cb78f4543ad67ed24df22bbc0bd27f9c8836693e [file] [log] [blame]
// 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
#define RAMDISK_SECTOR_SIZE 512
void
ramdisk_setup()
{
if (!CONFIG_COREBOOT_FLASH || !CONFIG_FLASH_FLOPPY)
return;
// Find image.
int iscomp;
struct cbfs_file *file = cbfs_finddataprefix("floppyimg/", NULL, &iscomp);
if (!file)
return;
u32 size = cbfs_datasize(file, iscomp);
dprintf(3, "Found floppy file %s of size %d\n", cbfs_filename(file), 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.
struct e820entry *e = find_high_area(size);
if (!e) {
dprintf(3, "No ram for ramdisk\n");
return;
}
u32 loc = e->start + e->size - size;
add_e820(loc, size, E820_RESERVED);
// Copy image into ram.
cbfs_copyfile(file, (void*)loc, size, iscomp);
// Setup driver.
dprintf(1, "Mapping CBFS floppy %s to addr %x\n", cbfs_filename(file), loc);
addFloppy(loc, ftype, DTYPE_RAMDISK);
}
static int
ramdisk_op(struct disk_op_s *op, int iswrite)
{
u32 offset = GET_GLOBAL(Drives.drives[op->driveid].cntl_id);
offset += (u32)op->lba * RAMDISK_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 0x1587 to copy data.
struct bregs br;
memset(&br, 0, sizeof(br));
br.ah = 0x87;
br.es = GET_SEG(SS);
br.si = (u32)gdt;
br.cx = op->count * RAMDISK_SECTOR_SIZE / 2;
call16_int(0x15, &br);
return DISK_RET_SUCCESS;
}
int
process_ramdisk_op(struct disk_op_s *op)
{
if (!CONFIG_COREBOOT_FLASH || !CONFIG_FLASH_FLOPPY)
return 0;
switch (op->command) {
case CMD_READ:
return ramdisk_op(op, 0);
case CMD_WRITE:
return ramdisk_op(op, 1);
case CMD_VERIFY:
case CMD_FORMAT:
case CMD_RESET:
return DISK_RET_SUCCESS;
default:
op->count = 0;
return DISK_RET_EPARAM;
}
}