1 files changed, 108 insertions, 0 deletions
diff --git a/roms/seabios/src/hw/ramdisk.c b/roms/seabios/src/hw/ramdisk.c
new file mode 100644
index 000000000..b9e9baabc
--- /dev/null
+++ b/roms/seabios/src/hw/ramdisk.c
@@ -0,0 +1,108 @@
+// 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 "biosvar.h" // GET_GLOBALFLAT
+#include "block.h" // struct drive_s
+#include "bregs.h" // struct bregs
+#include "e820map.h" // e820_add
+#include "malloc.h" // memalign_tmphigh
+#include "memmap.h" // PAGE_SIZE
+#include "output.h" // dprintf
+#include "romfile.h" // romfile_findprefix
+#include "stacks.h" // call16_int
+#include "std/disk.h" // DISK_RET_SUCCESS
+#include "string.h" // memset
+#include "util.h" // process_ramdisk_op
+
+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;
+    }
+    e820_add((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 = init_floppy((u32)pos, ftype);
+    if (!drive)
+        return;
+    drive->type = DTYPE_RAMDISK;
+    dprintf(1, "Mapping floppy %s to addr %p\n", filename, pos);
+    char *desc = znprintf(MAXDESCSIZE, "Ramdisk [%s]", &filename[10]);
+    boot_add_floppy(drive, desc, bootprio_find_named_rom(filename, 0));
+}
+
+static int
+ramdisk_copy(struct disk_op_s *op, int iswrite)
+{
+    u32 offset = GET_GLOBALFLAT(op->drive_fl->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
+ramdisk_process_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);
+    default:
+        return default_process_op(op);
+    }
+}