Aren/rulimine
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

bios/disk: Add manual sector size detection code

Browse Source
This commit is contained in:
mintsuki 2022-09-01 04:22:30 +02:00
parent c34db50cfd
commit 1b630659d9
1 changed files with 68 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

74
common/drivers/disk.s2.c
View File

@ -42,7 +42,7 @@ struct dap {
#define XFER_BUF_SIZE (xfer_sizes[SIZEOF_ARRAY(xfer_sizes) - 1] * 512)
static const size_t xfer_sizes[] = { 1, 2, 4, 8, 16, 24, 32, 48, 64 };
static void *xfer_buf = NULL;
static uint8_t *xfer_buf = NULL;
static size_t fastest_xfer_size(struct volume *volume) {
struct dap dap = {0};
@ -125,6 +125,67 @@ int disk_read_sectors(struct volume *volume, void *buf, uint64_t block, size_t c
return DISK_SUCCESS;
}
static bool detect_sector_size(struct volume *volume) {
struct dap dap = {0};
if (xfer_buf == NULL)
xfer_buf = conv_mem_alloc(XFER_BUF_SIZE);
dap.size = 16;
dap.count = 1;
dap.segment = rm_seg(xfer_buf);
dap.offset = rm_off(xfer_buf);
dap.lba = 0;
struct rm_regs r = {0};
r.eax = 0x4200;
r.edx = volume->drive;
r.esi = (uint32_t)rm_off(&dap);
r.ds = rm_seg(&dap);
struct rm_regs r_copy = r;
struct dap dap_copy = dap;
memset(xfer_buf, 0, XFER_BUF_SIZE);
rm_int(0x13, &r, &r);
if (r.eflags & EFLAGS_CF) {
return false;
}
size_t sector_size_a = 0;
for (size_t i = XFER_BUF_SIZE - 1; i >= 0; i--) {
if (xfer_buf[i] != 0) {
sector_size_a = i + 1;
break;
}
}
r = r_copy;
dap = dap_copy;
memset(xfer_buf, 0xff, XFER_BUF_SIZE);
rm_int(0x13, &r, &r);
if (r.eflags & EFLAGS_CF) {
return false;
}
size_t sector_size_b = 0;
for (size_t i = XFER_BUF_SIZE - 1; i >= 0; i--) {
if (xfer_buf[i] != 0xff) {
sector_size_b = i + 1;
break;
}
}
volume->sector_size = sector_size_a > sector_size_b ? sector_size_a : sector_size_b;
return true;
}
void disk_create_index(void) {
volume_index = ext_mem_alloc(sizeof(struct volume) * MAX_VOLUMES);
@ -148,21 +209,22 @@ void disk_create_index(void) {
rm_int(0x13, &r, &r);
if (r.eflags & EFLAGS_CF)
continue;
if (drive_params.bytes_per_sect == 0)
if (r.eflags & EFLAGS_CF) {
continue;
}
struct volume *block = ext_mem_alloc(sizeof(struct volume));
block->drive = drive;
block->partition = 0;
block->sector_size = drive_params.bytes_per_sect;
block->first_sect = 0;
block->sect_count = drive_params.lba_count;
block->max_partition = -1;
if (!detect_sector_size(block)) {
continue;
}
if (drive_params.info_flags & (1 << 2) && drive > 0x8f) {
// The medium could not be present (e.g.: CD-ROMs)
// Do a test run to see if we can actually read it