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BIOS disk driver: do not make assumptions about sector size being 512 bytes

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mintsuki 2020-10-18 06:35:20 +02:00
parent a82dc582c7
commit 0e09a8924b
2 changed files with 22 additions and 6 deletions
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limine.bin
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28
stage2/drivers/disk.c
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@ -8,9 +8,8 @@
#include <lib/print.h>
#include <mm/pmm.h>
#define SECTOR_SIZE 512
#define BLOCK_SIZE_IN_SECTORS 16
#define BLOCK_SIZE (SECTOR_SIZE * BLOCK_SIZE_IN_SECTORS)
#define BLOCK_SIZE (sector_size * BLOCK_SIZE_IN_SECTORS)
#define CACHE_INVALID (~((uint64_t)0))
@ -27,7 +26,7 @@ struct dap {
static struct dap *dap = NULL;
static int cache_block(int drive, uint64_t block) {
static int cache_block(int drive, uint64_t block, int sector_size) {
if (block == cached_block)
return 0;
@ -55,8 +54,6 @@ static int cache_block(int drive, uint64_t block) {
if (r.eflags & EFLAGS_CF) {
int ah = (r.eax >> 8) & 0xff;
panic("Disk error %x. Drive %x, LBA %x.\n", ah, drive, dap->lba);
cached_block = CACHE_INVALID;
return ah;
}
cached_block = block;
@ -65,12 +62,31 @@ static int cache_block(int drive, uint64_t block) {
}
int read(int drive, void *buffer, uint64_t loc, uint64_t count) {
struct rm_regs r = {0};
struct bios_drive_params drive_params;
r.eax = 0x4800;
r.edx = drive;
r.ds = rm_seg(&drive_params);
r.esi = rm_off(&drive_params);
drive_params.buf_size = sizeof(struct bios_drive_params);
rm_int(0x13, &r, &r);
if (r.eflags & EFLAGS_CF) {
int ah = (r.eax >> 8) & 0xff;
panic("Disk error %x. Drive %x.\n", ah, drive);
}
int sector_size = drive_params.bytes_per_sect;
uint64_t progress = 0;
while (progress < count) {
uint64_t block = (loc + progress) / BLOCK_SIZE;
int ret;
if ((ret = cache_block(drive, block)))
if ((ret = cache_block(drive, block, sector_size)))
return ret;
uint64_t chunk = count - progress;