[block] Replace gPXE block-device API with an iPXE asynchronous interface

The block device interface used in gPXE predates the invention of even
the old gPXE data-transfer interface, let alone the current iPXE
generic asynchronous interface mechanism.  Bring this old code up to
date, with the following benefits:

 o  Block device commands can be cancelled by the requestor.  The INT 13
    layer uses this to provide a global timeout on all INT 13 calls,
    with the result that an unexpected passive failure mode (such as
    an iSCSI target ACKing the request but never sending a response)
    will lead to a timeout that gets reported back to the INT 13 user,
    rather than simply freezing the system.

 o  INT 13,00 (reset drive) is now able to reset the underlying block
    device.  INT 13 users, such as DOS, that use INT 13,00 as a method
    for error recovery now have a chance of recovering.

 o  All block device commands are tagged, with a numerical tag that
    will show up in debugging output and in packet captures; this will
    allow easier interpretation of bug reports that include both
    sources of information.

 o  The extremely ugly hacks used to generate the boot firmware tables
    have been eradicated and replaced with a generic acpi_describe()
    method (exploiting the ability of iPXE interfaces to pass through
    methods to an underlying interface).  The ACPI tables are now
    built in a shared data block within .bss16, rather than each
    requiring dedicated space in .data16.

 o  The architecture-independent concept of a SAN device has been
    exposed to the iPXE core through the sanboot API, which provides
    calls to hook, unhook, boot, and describe SAN devices.  This
    allows for much more flexible usage patterns (such as hooking an
    empty SAN device and then running an OS installer via TFTP).

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 40 insertions, 45 deletions

diff --git a/src/include/ipxe/ata.h b/src/include/ipxe/ata.h
index 043e37051..b7f02d655 100644
--- a/src/include/ipxe/ata.h
+++ b/src/include/ipxe/ata.h
@@ -2,9 +2,8 @@
 #define _IPXE_ATA_H
 
 #include <stdint.h>
-#include <ipxe/blockdev.h>
 #include <ipxe/uaccess.h>
-#include <ipxe/refcnt.h>
+#include <ipxe/interface.h>
 
 /** @file
  *
@@ -104,7 +103,7 @@ struct ata_cb {
 	uint8_t device;
 	/** Command/status register */
 	uint8_t cmd_stat;
-	/** LBA48 addressing flag */
+	/** Use LBA48 extended addressing */
 	int lba48;
 };
 
@@ -138,25 +137,8 @@ struct ata_cb {
 /** "Identify" command */
 #define ATA_CMD_IDENTIFY 0xec
 
-/** An ATA command */
-struct ata_command {
-	/** ATA command block */
-	struct ata_cb cb;
-	/** Data-out buffer (may be NULL)
-	 *
-	 * If non-NULL, this buffer must be ata_command::cb::count
-	 * sectors in size.
-	 */
-	userptr_t data_out;
-	/** Data-in buffer (may be NULL)
-	 *
-	 * If non-NULL, this buffer must be ata_command::cb::count
-	 * sectors in size.
-	 */
-	userptr_t data_in;
-	/** Command status code */
-	int rc;
-};
+/** Command completed in error */
+#define ATA_STAT_ERR 0x01
 
 /**
  * Structure returned by ATA IDENTIFY command
@@ -165,13 +147,15 @@ struct ata_command {
  * so we implement only a few fields.
  */
 struct ata_identity {
-	uint16_t ignore_a[60]; /* words 0-59 */
+	uint16_t ignore_a[27]; /* words 0-26 */
+	uint16_t model[20]; /* words 27-46 */
+	uint16_t ignore_b[13]; /* words 47-59 */
 	uint32_t lba_sectors; /* words 60-61 */
-	uint16_t ignore_b[21]; /* words 62-82 */
+	uint16_t ignore_c[21]; /* words 62-82 */
 	uint16_t supports_lba48; /* word 83 */
-	uint16_t ignore_c[16]; /* words 84-99 */
+	uint16_t ignore_d[16]; /* words 84-99 */
 	uint64_t lba48_sectors; /* words 100-103 */
-	uint16_t ignore_d[152]; /* words 104-255 */
+	uint16_t ignore_e[152]; /* words 104-255 */
 };
 
 /** Supports LBA48 flag */
@@ -180,30 +164,41 @@ struct ata_identity {
 /** ATA sector size */
 #define ATA_SECTOR_SIZE 512
 
-/** An ATA device */
-struct ata_device {
-	/** Block device interface */
-	struct block_device blockdev;
-	/** Device number
+/** An ATA command information unit */
+struct ata_cmd {
+	/** ATA command block */
+	struct ata_cb cb;
+	/** Data-out buffer (may be NULL)
 	 *
-	 * Must be ATA_DEV_MASTER or ATA_DEV_SLAVE.
+	 * If non-NULL, this buffer must be ata_command::cb::count
+	 * sectors in size.
 	 */
-	int device;
-	/** LBA48 extended addressing */
-	int lba48;
-	/**
-	 * Issue ATA command
+	userptr_t data_out;
+	/** Data-out buffer length
 	 *
-	 * @v ata		ATA device
-	 * @v command		ATA command
-	 * @ret rc		Return status code
+	 * Must be zero if @c data_out is NULL
 	 */
-	int ( * command ) ( struct ata_device *ata,
-			    struct ata_command *command );
-	/** Backing device */
-	struct refcnt *backend;
+	size_t data_out_len;
+	/** Data-in buffer (may be NULL)
+	 *
+	 * If non-NULL, this buffer must be ata_command::cb::count
+	 * sectors in size.
+	 */
+	userptr_t data_in;
+	/** Data-in buffer length
+	 *
+	 * Must be zero if @c data_in is NULL
+	 */
+	size_t data_in_len;
 };
 
-extern int init_atadev ( struct ata_device *ata );
+extern int ata_command ( struct interface *control, struct interface *data,
+			 struct ata_cmd *command );
+#define ata_command_TYPE( object_type )					\
+	typeof ( int ( object_type, struct interface *data,		\
+		       struct ata_cmd *command ) )
+
+extern int ata_open ( struct interface *block, struct interface *ata,
+		      unsigned int device, unsigned int max_count );
 
 #endif /* _IPXE_ATA_H */