[int13] Add infrastructure to support EDD version 4.0

Support the extensions mandated by EDD 4.0, including:

 o  the ability to specify a flat physical address in a disk address
    packet,

 o  the ability to specify a sector count greater than 127 in a disk
    address packet,

 o  support for all functions within the Fixed Disk Access and EDD
    Support subsets,

 o  the ability to describe a device using EDD Device Path Information.

This implementation is based on draft revision 3 of the EDD 4.0
specification, with reference to the EDD 3.0 specification.  It is
possible that this implementation may need to change in order to
conform to the final published EDD 4.0 specification.

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

1 files changed, 216 insertions, 23 deletions

diff --git a/src/arch/i386/interface/pcbios/int13.c b/src/arch/i386/interface/pcbios/int13.c
index 97110fde..e0acc07c 100644
--- a/src/arch/i386/interface/pcbios/int13.c
+++ b/src/arch/i386/interface/pcbios/int13.c
@@ -35,6 +35,8 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <ipxe/timer.h>
 #include <ipxe/acpi.h>
 #include <ipxe/sanboot.h>
+#include <ipxe/device.h>
+#include <ipxe/pci.h>
 #include <realmode.h>
 #include <bios.h>
 #include <biosint.h>
@@ -654,8 +656,10 @@ static int int13_extension_check ( struct int13_drive *int13 __unused,
 	if ( ix86->regs.bx == 0x55aa ) {
 		DBGC2 ( int13, "INT13 extensions installation check\n" );
 		ix86->regs.bx = 0xaa55;
-		ix86->regs.cx = INT13_EXTENSION_LINEAR;
-		return INT13_EXTENSION_VER_1_X;
+		ix86->regs.cx = ( INT13_EXTENSION_LINEAR |
+				  INT13_EXTENSION_EDD |
+				  INT13_EXTENSION_64BIT );
+		return INT13_EXTENSION_VER_3_0;
 	} else {
 		return -INT13_STATUS_INVALID;
 	}
@@ -678,25 +682,56 @@ static int int13_extended_rw ( struct int13_drive *int13,
 						    userptr_t buffer,
 						    size_t len ) ) {
 	struct int13_disk_address addr;
+	uint8_t bufsize;
 	uint64_t lba;
 	unsigned long count;
 	userptr_t buffer;
 	int rc;
 
+	/* Get buffer size */
+	get_real ( bufsize, ix86->segs.ds,
+		   ( ix86->regs.si + offsetof ( typeof ( addr ), bufsize ) ) );
+	if ( bufsize < offsetof ( typeof ( addr ), buffer_phys ) ) {
+		DBGC2 ( int13, "<invalid buffer size %#02x\n>\n", bufsize );
+		return -INT13_STATUS_INVALID;
+	}
+
 	/* Read parameters from disk address structure */
-	copy_from_real ( &addr, ix86->segs.ds, ix86->regs.si, sizeof ( addr ));
+	memset ( &addr, 0, sizeof ( addr ) );
+	copy_from_real ( &addr, ix86->segs.ds, ix86->regs.si, bufsize );
 	lba = addr.lba;
-	count = addr.count;
-	buffer = real_to_user ( addr.buffer.segment, addr.buffer.offset );
+	DBGC2 ( int13, "LBA %08llx <-> ", ( ( unsigned long long ) lba ) );
+	if ( ( addr.count == 0xff ) ||
+	     ( ( addr.buffer.segment == 0xffff ) &&
+	       ( addr.buffer.offset == 0xffff ) ) ) {
+		buffer = phys_to_user ( addr.buffer_phys );
+		DBGC2 ( int13, "%08llx",
+			( ( unsigned long long ) addr.buffer_phys ) );
+	} else {
+		buffer = real_to_user ( addr.buffer.segment,
+					addr.buffer.offset );
+		DBGC2 ( int13, "%04x:%04x", addr.buffer.segment,
+			addr.buffer.offset );
+	}
+	if ( addr.count <= 0x7f ) {
+		count = addr.count;
+	} else if ( addr.count == 0xff ) {
+		count = addr.long_count;
+	} else {
+		DBGC2 ( int13, " <invalid count %#02x>\n", addr.count );
+		return -INT13_STATUS_INVALID;
+	}
+	DBGC2 ( int13, " (count %ld)\n", count );
 
-	DBGC2 ( int13, "LBA %08llx <-> %04x:%04x (count %ld)\n",
-		( ( unsigned long long ) lba ), addr.buffer.segment,
-		addr.buffer.offset, count );
-	
 	/* Read from / write to block device */
 	if ( ( rc = int13_rw ( int13, lba, count, buffer, block_rw ) ) != 0 ) {
 		DBGC ( int13, "INT13 drive %02x extended I/O failed: %s\n",
 		       int13->drive, strerror ( rc ) );
+		/* Record that no blocks were transferred successfully */
+		addr.count = 0;
+		put_real ( addr.count, ix86->segs.ds,
+			   ( ix86->regs.si +
+			     offsetof ( typeof ( addr ), count ) ) );
 		return -INT13_STATUS_READ_ERROR;
 	}
 
@@ -730,6 +765,117 @@ static int int13_extended_write ( struct int13_drive *int13,
 }
 
 /**
+ * INT 13, 44 - Verify sectors
+ *
+ * @v int13		Emulated drive
+ * @v ds:si		Disk address packet
+ * @ret status		Status code
+ */
+static int int13_extended_verify ( struct int13_drive *int13,
+				   struct i386_all_regs *ix86 ) {
+	struct int13_disk_address addr;
+	uint64_t lba;
+	unsigned long count;
+
+	/* Read parameters from disk address structure */
+	if ( DBG_EXTRA ) {
+		copy_from_real ( &addr, ix86->segs.ds, ix86->regs.si,
+				 sizeof ( addr ));
+		lba = addr.lba;
+		count = addr.count;
+		DBGC2 ( int13, "Verify: LBA %08llx (count %ld)\n",
+			( ( unsigned long long ) lba ), count );
+	}
+
+	/* We have no mechanism for verifying sectors */
+	return -INT13_STATUS_INVALID;
+}
+
+/**
+ * INT 13, 44 - Extended seek
+ *
+ * @v int13		Emulated drive
+ * @v ds:si		Disk address packet
+ * @ret status		Status code
+ */
+int int13_extended_seek ( struct int13_drive *int13,
+			  struct i386_all_regs *ix86 ) {
+	struct int13_disk_address addr;
+	uint64_t lba;
+	unsigned long count;
+
+	/* Read parameters from disk address structure */
+	if ( DBG_EXTRA ) {
+		copy_from_real ( &addr, ix86->segs.ds, ix86->regs.si,
+				 sizeof ( addr ));
+		lba = addr.lba;
+		count = addr.count;
+		DBGC2 ( int13, "Seek: LBA %08llx (count %ld)\n",
+			( ( unsigned long long ) lba ), count );
+	}
+
+	/* Ignore and return success */
+	return 0;
+}
+
+/**
+ * Build device path information
+ *
+ * @v int13		Emulated drive
+ * @v dpi		Device path information
+ * @ret rc		Return status code
+ */
+static int int13_device_path_info ( struct int13_drive *int13,
+				    struct edd_device_path_information *dpi ) {
+	struct device *device;
+	struct device_description *desc;
+	unsigned int i;
+	uint8_t sum = 0;
+	int rc;
+
+	/* Get underlying hardware device */
+	device = identify_device ( &int13->block );
+	if ( ! device ) {
+		DBGC ( int13, "INT13 drive %02x cannot identify hardware "
+		       "device\n", int13->drive );
+		return -ENODEV;
+	}
+
+	/* Fill in bus type and interface path */
+	desc = &device->desc;
+	switch ( desc->bus_type ) {
+	case BUS_TYPE_PCI:
+		dpi->host_bus_type.type = EDD_BUS_TYPE_PCI;
+		dpi->interface_path.pci.bus = PCI_BUS ( desc->location );
+		dpi->interface_path.pci.slot = PCI_SLOT ( desc->location );
+		dpi->interface_path.pci.function = PCI_FUNC ( desc->location );
+		dpi->interface_path.pci.channel = 0xff; /* unused */
+		break;
+	default:
+		DBGC ( int13, "INT13 drive %02x unrecognised bus type %d\n",
+		       int13->drive, desc->bus_type );
+		return -ENOTSUP;
+	}
+
+	/* Get EDD block device description */
+	if ( ( rc = edd_describe ( &int13->block, &dpi->interface_type,
+				   &dpi->device_path ) ) != 0 ) {
+		DBGC ( int13, "INT13 drive %02x cannot identify block device: "
+		       "%s\n", int13->drive, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Fill in common fields and fix checksum */
+	dpi->key = EDD_DEVICE_PATH_INFO_KEY;
+	dpi->len = sizeof ( *dpi );
+	for ( i = 0 ; i < sizeof ( *dpi ) ; i++ )
+		sum += *( ( ( uint8_t * ) dpi ) + i );
+	dpi->checksum -= sum;
+
+	return 0;
+}
+
+/**
  * INT 13, 48 - Get extended parameters
  *
  * @v int13		Emulated drive
@@ -738,21 +884,62 @@ static int int13_extended_write ( struct int13_drive *int13,
  */
 static int int13_get_extended_parameters ( struct int13_drive *int13,
 					   struct i386_all_regs *ix86 ) {
-	struct int13_disk_parameters params = {
-		.bufsize = sizeof ( params ),
-		.flags = INT13_FL_DMA_TRANSPARENT,
-		.cylinders = int13->cylinders,
-		.heads = int13->heads,
-		.sectors_per_track = int13->sectors_per_track,
-		.sectors = int13->capacity.blocks,
-		.sector_size = int13->capacity.blksize,
-	};
-	
-	DBGC2 ( int13, "Get extended drive parameters to %04x:%04x\n",
-		ix86->segs.ds, ix86->regs.si );
+	struct int13_disk_parameters params;
+	struct segoff address;
+	size_t len = sizeof ( params );
+	uint16_t bufsize;
+	int rc;
+
+	/* Get buffer size */
+	get_real ( bufsize, ix86->segs.ds,
+		   ( ix86->regs.si + offsetof ( typeof ( params ), bufsize )));
+
+	DBGC2 ( int13, "Get extended drive parameters to %04x:%04x+%02x\n",
+		ix86->segs.ds, ix86->regs.si, bufsize );
+
+	/* Build drive parameters */
+	memset ( &params, 0, sizeof ( params ) );
+	params.flags = INT13_FL_DMA_TRANSPARENT;
+	if ( ( int13->cylinders < 1024 ) &&
+	     ( int13->capacity.blocks <= INT13_MAX_CHS_SECTORS ) ) {
+		params.flags |= INT13_FL_CHS_VALID;
+	}
+	params.cylinders = int13->cylinders;
+	params.heads = int13->heads;
+	params.sectors_per_track = int13->sectors_per_track;
+	params.sectors = int13->capacity.blocks;
+	params.sector_size = int13->capacity.blksize;
+	memset ( &params.dpte, 0xff, sizeof ( params.dpte ) );
+	if ( ( rc = int13_device_path_info ( int13, &params.dpi ) ) != 0 ) {
+		DBGC ( int13, "INT13 drive %02x could not provide device "
+		       "path information: %s\n",
+		       int13->drive, strerror ( rc ) );
+		len = offsetof ( typeof ( params ), dpi );
+	}
+
+	/* Calculate returned "buffer size" (which will be less than
+	 * the length actually copied if device path information is
+	 * present).
+	 */
+	if ( bufsize < offsetof ( typeof ( params ), dpte ) )
+		return -INT13_STATUS_INVALID;
+	if ( bufsize < offsetof ( typeof ( params ), dpi ) ) {
+		params.bufsize = offsetof ( typeof ( params ), dpte );
+	} else {
+		params.bufsize = offsetof ( typeof ( params ), dpi );
+	}
+
+	DBGC ( int13, "INT 13 drive %02x described using extended "
+	       "parameters:\n", int13->drive );
+	address.segment = ix86->segs.ds;
+	address.offset = ix86->regs.si;
+	DBGC_HDA ( int13, address, &params, len );
+
+	/* Return drive parameters */
+	if ( len > bufsize )
+		len = bufsize;
+	copy_to_real ( ix86->segs.ds, ix86->regs.si, &params, len );
 
-	copy_to_real ( ix86->segs.ds, ix86->regs.si, &params,
-		       sizeof ( params ) );
 	return 0;
 }
 
@@ -814,6 +1001,12 @@ static __asmcall void int13 ( struct i386_all_regs *ix86 ) {
 		case INT13_EXTENDED_WRITE:
 			status = int13_extended_write ( int13, ix86 );
 			break;
+		case INT13_EXTENDED_VERIFY:
+			status = int13_extended_verify ( int13, ix86 );
+			break;
+		case INT13_EXTENDED_SEEK:
+			status = int13_extended_seek ( int13, ix86 );
+			break;
 		case INT13_GET_EXTENDED_PARAMETERS:
 			status = int13_get_extended_parameters ( int13, ix86 );
 			break;