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#ifndef _GPXE_ATA_H
#define _GPXE_ATA_H
#include <stdint.h>
#include <gpxe/blockdev.h>
#include <gpxe/uaccess.h>
/** @file
*
* ATA devices
*
*/
/**
* An ATA Logical Block Address
*
* ATA controllers have three byte-wide registers for specifying the
* block address: LBA Low, LBA Mid and LBA High. This allows for a
* 24-bit address. Some devices support the "48-bit address feature
* set" (LBA48), in which case each of these byte-wide registers is
* actually a two-entry FIFO, and the "previous" byte pushed into the
* FIFO is used as the corresponding high-order byte. So, to set up
* the 48-bit address 0x123456abcdef, you would issue
*
* 0x56 -> LBA Low register
* 0xef -> LBA Low register
* 0x34 -> LBA Mid register
* 0xcd -> LBA Mid register
* 0x12 -> LBA High register
* 0xab -> LBA High register
*
* This structure encapsulates this information by providing a single
* 64-bit integer in native byte order, unioned with bytes named so
* that the sequence becomes
*
* low_prev -> LBA Low register
* low_cur -> LBA Low register
* mid_prev -> LBA Mid register
* mid_cur -> LBA Mid register
* high_prev -> LBA High register
* high_cur -> LBA High register
*
* Just to complicate matters further, in non-LBA48 mode it is
* possible to have a 28-bit address, in which case bits 27:24 must be
* written into the low four bits of the Device register.
*/
union ata_lba {
/** LBA as a 64-bit integer in native-endian order */
uint64_t native;
/** ATA registers */
struct {
#if __BYTE_ORDER == __LITTLE_ENDIAN
uint8_t low_cur;
uint8_t mid_cur;
uint8_t high_cur;
uint8_t low_prev;
uint8_t mid_prev;
uint8_t high_prev;
uint8_t pad[2];
#elif __BYTE_ORDER == __BIG_ENDIAN
uint8_t pad[2];
uint8_t high_prev;
uint8_t mid_prev;
uint8_t low_prev;
uint8_t high_cur;
uint8_t mid_cur;
uint8_t low_cur;
#else
#error "I need a byte order"
#endif
} bytes;
};
/** An ATA 2-byte FIFO register */
union ata_fifo {
/** Value in native-endian order */
uint16_t native;
/** ATA registers */
struct {
#if __BYTE_ORDER == __LITTLE_ENDIAN
uint8_t cur;
uint8_t prev;
#elif __BYTE_ORDER == __BIG_ENDIAN
uint8_t prev;
uint8_t cur;
#else
#error "I need a byte order"
#endif
} bytes;
};
/** ATA command block */
struct ata_cb {
/** Logical block address */
union ata_lba lba;
/** Sector count */
union ata_fifo count;
/** Error/feature register */
union ata_fifo err_feat;
/** Device register */
uint8_t device;
/** Command/status register */
uint8_t cmd_stat;
/** Flags
*
* This field does not correspond to any ATA register.
*/
uint8_t flags;
};
/** LBA48 extended addressing */
#define ATA_FL_LBA48 0x40
/** Device 1 ("slave") */
#define ATA_FL_SLAVE 0x10
/** Write command */
#define ATA_FL_WRITE 0x01
/** Obsolete bits in the ATA device register */
#define ATA_DEV_OBSOLETE 0xa0
/** LBA flag in the ATA device register */
#define ATA_DEV_LBA 0x40
/** "Read sectors" command */
#define ATA_CMD_READ 0x20
/** "Write sectors" command */
#define ATA_CMD_WRITE 0x30
/** "Identify" command */
#define ATA_CMD_IDENTIFY 0xec
/** "Extended (LBA48)" command modifier
*
* This doesn't apply to all ATA commands, but it does for @c
* ATA_CMD_READ and @c ATA_CMD_WRITE.
*/
#define ATA_CMD_EXT 0x04
/** An ATA command */
struct ata_command {
/** ATA command block */
struct ata_cb cb;
/** Data buffer */
userptr_t data;
/** Data buffer length */
size_t data_len;
};
/**
* Structure returned by ATA IDENTIFY command
*
* This is a huge structure with many fields that we don't care about,
* so we implement only a few fields.
*/
struct ata_identity {
uint16_t ignore_a[60]; /* words 0-59 */
uint32_t lba_sectors; /* words 60-61 */
uint16_t ignore_b[21]; /* words 62-82 */
uint16_t supports_lba48; /* word 83 */
uint16_t ignore_c[16]; /* words 84-99 */
uint64_t lba48_sectors; /* words 100-103 */
uint16_t ignore_d[152]; /* words 104-255 */
};
/** Supports LBA48 flag */
#define ATA_SUPPORTS_LBA48 ( 1 << 10 )
/** ATA sector size */
#define ATA_SECTOR_SIZE 512
/** An ATA device */
struct ata_device {
/** Block device interface */
struct block_device blockdev;
/** Flags */
int flags;
/**
* Issue ATA command
*
* @v ata ATA device
* @v command ATA command
* @ret rc Return status code
*/
int ( * command ) ( struct ata_device *ata,
struct ata_command *command );
};
extern int init_atadev ( struct ata_device *ata );
#endif /* _GPXE_ATA_H */
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