Add INT 13 emulation layer (which provides an interface to gPXE block

devices).

src/arch/i386/include/int13.h

@@ -0,0 +1,157 @@
+#ifndef INT13_H
+#define INT13_H
+
+/** @file
+ *
+ * INT 13 emulation
+ *
+ */
+
+#include <stdint.h>
+#include <gpxe/list.h>
+
+struct block_device;
+
+/**
+ * @defgroup int13ops INT 13 operation codes
+ * @{
+ */
+
+/** Reset disk system */
+#define INT13_RESET			0x00
+/** Get status of last operation */
+#define INT13_GET_LAST_STATUS		0x01
+/** Read sectors */
+#define INT13_READ_SECTORS		0x02
+/** Write sectors */
+#define INT13_WRITE_SECTORS		0x03
+/** Get drive parameters */
+#define INT13_GET_PARAMETERS		0x08
+/** Extended read */
+#define INT13_EXTENDED_READ		0x42
+/** Extended write */
+#define INT13_EXTENDED_WRITE		0x43
+/** Get extended drive parameters */
+#define INT13_GET_EXTENDED_PARAMETERS	0x48
+
+/** @} */
+
+/**
+ * @defgroup int13status INT 13 status codes
+ * @{
+ */
+
+/** Operation completed successfully */
+#define INT13_STATUS_SUCCESS		0x00
+/** Invalid function or parameter */
+#define INT13_STATUS_INVALID		0x01
+/** Read error */
+#define INT13_STATUS_READ_ERROR		0x04
+/** Write error */
+#define INT13_STATUS_WRITE_ERROR	0xcc
+
+/** @} */
+
+/** Block size for non-extended INT 13 calls */
+#define INT13_BLKSIZE 512
+
+/** An INT 13 emulated drive */
+struct int13_drive {
+	/** List of all registered drives */
+	struct list_head list;
+
+	/** Underlying block device */
+	struct block_device *blockdev;
+
+	/** BIOS drive number (0x80-0xff) */
+	unsigned int drive;
+	/** Number of cylinders
+	 *
+	 * The cylinder number field in an INT 13 call is ten bits
+	 * wide, giving a maximum of 1024 cylinders.  Conventionally,
+	 * when the 7.8GB limit of a CHS address is exceeded, it is
+	 * the number of cylinders that is increased beyond the
+	 * addressable limit.
+	 */
+	unsigned int cylinders;
+	/** Number of heads
+	 *
+	 * The head number field in an INT 13 call is eight bits wide,
+	 * giving a maximum of 256 heads.  However, apparently all
+	 * versions of MS-DOS up to and including Win95 fail with 256
+	 * heads, so the maximum encountered in practice is 255.
+	 */
+	unsigned int heads;
+	/** Number of sectors per track
+	 *
+	 * The sector number field in an INT 13 call is six bits wide,
+	 * giving a maximum of 63 sectors, since sector numbering
+	 * (unlike head and cylinder numbering) starts at 1, not 0.
+	 */
+	unsigned int sectors_per_track;
+
+	/** Status of last operation */
+	int last_status;
+};
+
+/** An INT 13 disk address packet */
+struct int13_disk_address {
+	/** Size of the packet, in bytes */
+	uint8_t bufsize;
+	/** Reserved, must be zero */
+	uint8_t reserved;
+	/** Block count */
+	uint16_t count;
+	/** Data buffer */
+	struct segoff buffer;
+	/** Starting block number */
+	uint64_t lba;
+	/** Data buffer (EDD-3.0 only) */
+	uint64_t buffer_phys;
+};
+
+/** INT 13 disk parameters */
+struct int13_disk_parameters {
+	/** Size of this structure */
+	uint16_t bufsize;
+	/** Flags */
+	uint16_t flags;
+	/** Number of cylinders */
+	uint32_t cylinders;
+	/** Number of heads */
+	uint32_t heads;
+	/** Number of sectors per track */
+	uint32_t sectors_per_track;
+	/** Total number of sectors on drive */
+	uint64_t sectors;
+	/** Bytes per sector */
+	uint16_t sector_size;
+	
+};
+
+/**
+ * @defgroup int13flags INT 13 disk parameter flags
+ * @{
+ */
+
+/** DMA boundary errors handled transparently */
+#define INT13_FL_DMA_TRANSPARENT 0x01
+/** CHS information is valid */
+#define INT13_FL_CHS_VALID	 0x02
+/** Removable drive */
+#define INT13_FL_REMOVABLE	 0x04
+/** Write with verify supported */
+#define INT13_FL_VERIFIABLE	 0x08
+/** Has change-line supported (valid only for removable drives) */
+#define INT13_FL_CHANGE_LINE	 0x10
+/** Drive can be locked (valid only for removable drives) */
+#define INT13_FL_LOCKABLE	 0x20
+/** CHS is max possible, not current media (valid only for removable drives) */
+#define INT13_FL_CHS_MAX	 0x40
+
+/** @} */
+
+extern void register_int13_drive ( struct int13_drive *drive );
+extern void unregister_int13_drive ( struct int13_drive *drive );
+
+#endif /* INT13_H */