EDD: x86 BIOS Enhanced Disk Drive support

The major changes implemented in this patch:
arch/i386/boot/setup.S - int13 real mode calls store results in empty_zero_page
arch/i386/kernel/setup.c - copy results from empty_zero_page to local storage
arch/i386/kernel/edd.c - module exports results via driverfs

x86 systems suffer from a disconnect between what BIOS believes is the
boot disk, and what Linux thinks BIOS thinks is the boot disk.  This
manifests itself in multi-disk systems - it's quite possible to
install a distribution, only to fail on reboot - the disk installed to
is not the disk BIOS is booting from.  Dell restricts our possible
standard factory installed Linux offerings to "disks on no more than
one controller" to avoid this problem, but mechanisms now exist to
solve it and allow such configurations.

BIOS Enhanced Disk Device Services (EDD) 3.0 provides the ability for
disk adapter BIOSs to tell the OS what it believes is the boot disk.
While this isn't widely implemented in BIOSs yet, it's time that Linux
received support to be ready as BIOSs with this feature do become
available.  At a minimum, LSI MegaRAID cards support this today.

EDD works by providing the bus (PCI, PCI-X, ISA, InfiniBand, PCI
Express, or HyperTransport) location (e.g. PCI 02:01.0) and interface
(ATAPI, ATA, SCSI, USB, 1394, FibreChannel, I2O, RAID, SATA) location
(e.g. SCSI ID 5 LUN 0) information for each BIOS int13 device.

The patch below creates CONFIG_EDD, that when defined, makes the
BIOS int13 calls to retrieve and store this information.  The data is
copied to a safe place in setup.c, and exported via driverfs.

Here's a sample driverfs tree with two BIOS int13 devices - dev 80 has
incorrect PCI bus information, thus no symlinks are made, but as much
info as possible is presented.  Dev 81 has correct PCI and SCSI
information, thus symlinks are made to the actual disc device.

/driverfs
|-- bios
|   |-- int13_dev80
|   |   |-- extensions
|   |   |-- host_bus
|   |   |-- info_flags
|   |   |-- interface
|   |   |-- raw_data
|   |   |-- sectors
|   |   `-- version
|   `-- int13_dev81
|       |-- extensions
|       |-- host_bus
|       |-- info_flags
|       |-- interface
|       |-- pci_dev -> ../../root/pci2/02:0c.0/03:00.0/04:00.0
|       |-- raw_data
|       |-- disc -> ../../root/pci2/02:0c.0/03:00.0/04:00.0/scsi4/4:0:0:0
|       |-- sectors
|       `-- version
|-- bus
|   |-- scsi
|   |   |-- devices
|   |   |   |-- 4:0:0:0 -> ../../../root/pci2/02:0c.0/03:00.0/04:00.0/scsi4/4:0:0:0
|   |   `-- drivers
|   |       `-- sd
`-- root
    |-- pci2
    |   |-- 02:0c.0
    |   |   |-- 03:00.0
    |   |   |   |-- 04:00.0
    |   |   |   |   |-- irq
    |   |   |   |   |-- name
    |   |   |   |   |-- power
    |   |   |   |   |-- resource
    |   |   |   |   `-- scsi4
    |   |   |   |       |-- 4:0:0:0
    |   |   |   |       |   |-- 4:0:0:0::p1
    |   |   |   |       |   |   |-- kdev
    |   |   |   |       |   |   |-- name
    |   |   |   |       |   |   |-- power
    |   |   |   |       |   |   `-- type
    |   |   |   |       |   |-- 4:0:0:0:disc
    |   |   |   |       |   |   |-- kdev
    |   |   |   |       |   |   |-- name
    |   |   |   |       |   |   |-- power
    |   |   |   |       |   |   `-- type
    |   |   |   |       |   |-- name
    |   |   |   |       |   |-- power
    |   |   |   |       |   `-- type


(Yes, the 'bios' top-level directory isn't the right place,
 and Patrick has promised to make something there in the future,
 at which point this can be moved.)

The 'raw_data' file contains the full set of information returned by BIOS
with extra error reporting.  This exists for vendor BIOS debugging purposes.

The 'host-bus' file contains the PCI (or ISA, HyperTransport, ...)
identifying information, as BIOS knows it.

The 'interface' file contains the SCSI (or IDE, USB, ...) identifying
information, as BIOS knows it.

The 'extensions' file lists the BIOS EDD extensions per spec.
The 'info_flags' file lists the BIOS EDD device information flags per spec.
The 'sectors' file reports the number of sectors BIOS believes this
device has.
The 'version' file lists the EDD version.  To have device path
information, this must be 0x30 or above.  Earlier EDD versions exist
without the device path - as much information as is available is presented.

At most 6 BIOS devices are reported, as that fills the space that's
left in the empty_zero_page.  In general you only care about device
80h, though for software RAID1 knowing what 81h is might be useful also.



Known issues:
- module unload leaves a directory around.  Seems related to
  creating symlinks in that directory.  Seen on kernel 2.5.41.
- refcounting of struct device objects could be improved.

TODO:
- Add IDE and USB disk device support
- when driverfs model of discs and partitions changes,
  update symlink accordingly.
- Get symlink creator helper functions exported from
  drivers/base instead of duplicating them here.
- move edd.[ch] to better locations if/when one is decided

I'd also like to acknowledge the help and comments received from Greg
KH and Patrick Mochel.  This isn't something driverfs was originally
conceived to handle, their assistance has been invaluable.

Please pull from:

BK:
    http://mdomsch.bkbits.net/linux-2.5-edd-tolinus

Patch (against 2.5.41+BK-current):
    http://domsch.com/linux/edd30/edd-driverfs-6.patch
    http://domsch.com/linux/edd30/edd-driverfs-6.patch.sign

Thanks,
Matt

-- 
Matt Domsch
Sr. Software Engineer, Lead Engineer, Architect
Dell Linux Solutions www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com

Documentation/i386/zero-page.txt

@@ -31,6 +31,7 @@ Offset	Type		Description
 
 0x1e0	unsigned long	ALT_MEM_K, alternative mem check, in Kb
 0x1e8	char		number of entries in E820MAP (below)
+0x1e9	unsigned char	number of entries in EDDBUF (below)
 0x1f1	char		size of setup.S, number of sectors
 0x1f2	unsigned short	MOUNT_ROOT_RDONLY (if !=0)
 0x1f4	unsigned short	size of compressed kernel-part in the
@@ -66,6 +67,7 @@ Offset	Type		Description
 0x220	4 bytes		(setup.S)
 0x224	unsigned short	setup.S heap end pointer
 0x2d0 - 0x600		E820MAP
+0x600 - 0x7D4		EDDBUF (setup.S)
 
 0x800	string, 2K max	COMMAND_LINE, the kernel commandline as
 			copied using CL_OFFSET.

arch/i386/Config.help

@@ -1075,3 +1075,11 @@ CONFIG_SCx200
 
   This support is also available as a module.  If compiled as a
   module, it will be called scx200.o.
+
+CONFIG_EDD
+  Say Y or M here if you want to enable BIOS Enhanced Disk Drive
+  Services real mode BIOS calls to determine which disk
+  BIOS tries boot from.  This information is then exported via driverfs.
+
+  This option is experimental, but believed to be safe,
+  and most disk controller BIOS vendors do not yet implement this feature.

arch/i386/boot/setup.S

@@ -44,6 +44,9 @@
  *
  * New A20 code ported from SYSLINUX by H. Peter Anvin. AMD Elan bugfixes
  * by Robert Schwebel, December 2001 <robert@schwebel.de>
+ *    
+ * BIOS Enhanced Disk Drive support
+ * by Matt Domsch <Matt_Domsch@dell.com> September 2002 
  *
  */
 
@@ -53,6 +56,7 @@
 #include <linux/compile.h>
 #include <asm/boot.h>
 #include <asm/e820.h>
+#include <asm/edd.h>    
 #include <asm/page.h>
 	
 /* Signature words to ensure LILO loaded us right */
@@ -543,6 +547,49 @@ no_32_apm_bios:
 done_apm_bios:
 #endif
 
+#if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
+# Do the BIOS Enhanced Disk Drive calls
+# This code is sensitive to the size of the structs in edd.h
+edd_start:  
+						# %ds points to the bootsector
+       						# result buffer for fn48
+    	movw	$EDDBUF+EDDEXTSIZE, %si		# in ds:si, fn41 results
+						# kept just before that    
+	movb	$0, (EDDNR)			# zero value at EDDNR
+    	movb	$0x80, %dl			# BIOS device 0x80
+
+edd_check_ext:
+	movb	$0x41, %ah			# Function 41
+	movw	$0x55aa, %bx			# magic
+	int	$0x13				# make the call
+	jc	edd_done			# no more BIOS devices
+
+    	cmpw	$0xAA55, %bx			# is magic right?
+	jne	edd_next			# nope, next...
+
+    	movb	%dl, %ds:-4(%si)		# store device number
+    	movb	%ah, %ds:-3(%si)		# store version
+	movw	%cx, %ds:-2(%si)		# store extensions
+	incb	(EDDNR)				# note that we stored something
+        
+edd_get_device_params:  
+	movw	$EDDPARMSIZE, %ds:(%si)		# put size
+    	movb	$0x48, %ah			# Function 48
+	int	$0x13				# make the call
+						# Don't check for fail return
+						# it doesn't matter.
+	movw	%si, %ax			# increment si
+	addw	$EDDPARMSIZE+EDDEXTSIZE, %ax
+	movw	%ax, %si
+
+edd_next:
+        incb	%dl				# increment to next device
+       	cmpb	$EDDMAXNR, (EDDNR) 		# Out of space?
+	jb	edd_check_ext			# keep looping
+    
+edd_done:   
+#endif
+
 # Now we want to move to protected mode ...
 	cmpw	$0, %cs:realmode_swtch
 	jz	rmodeswtch_normal

arch/i386/config.in

@@ -215,6 +215,10 @@ tristate '/dev/cpu/microcode - Intel IA32 CPU microcode support' CONFIG_MICROCOD
 tristate '/dev/cpu/*/msr - Model-specific register support' CONFIG_X86_MSR
 tristate '/dev/cpu/*/cpuid - CPU information support' CONFIG_X86_CPUID
 
+if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then
+   tristate 'BIOS Enhanced Disk Drive calls determine boot disk (EXPERIMENTAL)' CONFIG_EDD
+fi
+
 choice 'High Memory Support' \
 	"off           CONFIG_NOHIGHMEM \
 	 4GB           CONFIG_HIGHMEM4G \

arch/i386/defconfig

@@ -70,6 +70,7 @@ CONFIG_X86_MCE_P4THERMAL=y
 # CONFIG_MICROCODE is not set
 # CONFIG_X86_MSR is not set
 # CONFIG_X86_CPUID is not set
+# CONFIG_EDD is not set
 CONFIG_NOHIGHMEM=y
 # CONFIG_HIGHMEM4G is not set
 # CONFIG_HIGHMEM64G is not set

arch/i386/kernel/Makefile

@@ -26,6 +26,7 @@ obj-$(CONFIG_X86_LOCAL_APIC)	+= apic.o nmi.o
 obj-$(CONFIG_X86_IO_APIC)	+= io_apic.o
 obj-$(CONFIG_SOFTWARE_SUSPEND)	+= suspend.o
 obj-$(CONFIG_X86_NUMAQ)		+= numaq.o
+obj-$(CONFIG_EDD)             	+= edd.o
 
 EXTRA_AFLAGS   := -traditional
 

arch/i386/kernel/edd.c

+/*
+ * linux/arch/i386/kernel/edd.c
+ *  Copyright (C) 2002 Dell Computer Corporation
+ *  by Matt Domsch <Matt_Domsch@dell.com>
+ *
+ * BIOS Enhanced Disk Drive Services (EDD)
+ * conformant to T13 Committee www.t13.org
+ *   projects 1572D, 1484D, 1386D, 1226DT
+ *
+ * This code takes information provided by BIOS EDD calls
+ * fn41 - Check Extensions Present and
+ * fn48 - Get Device Parametes with EDD extensions
+ * made in setup.S, copied to safe structures in setup.c,
+ * and presents it in driverfs.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License v2.0 as published by
+ * the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+/*
+ * Known issues:
+ * - module unload leaves a directory around.  Seems related to
+ *   creating symlinks in that directory.  Seen on kernel 2.5.41.
+ * - refcounting of struct device objects could be improved.
+ *
+ * TODO:
+ * - Add IDE and USB disk device support
+ * - when driverfs model of discs and partitions changes,
+ *   update symlink accordingly.
+ * - Get symlink creator helper functions exported from
+ *   drivers/base instead of duplicating them here.
+ * - move edd.[ch] to better locations if/when one is decided
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/stat.h>
+#include <linux/err.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <linux/limits.h>
+#include <linux/driverfs_fs.h>
+#include <linux/pci.h>
+#include <asm/edd.h>
+#include <linux/device.h>
+#include <linux/blkdev.h>
+/* FIXME - this really belongs in include/scsi/scsi.h */
+#include <../drivers/scsi/scsi.h>
+#include <../drivers/scsi/hosts.h>
+
+MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
+MODULE_DESCRIPTION("driverfs interface to BIOS EDD information");
+MODULE_LICENSE("GPL");
+
+#define EDD_VERSION "0.06 2002-Oct-09"
+#define EDD_DEVICE_NAME_SIZE 16
+#define REPORT_URL "http://domsch.com/linux/edd30/results.html"
+
+/*
+ * bios_dir may go away completely,
+ * and it definitely won't be at the root
+ * of driverfs forever.
+ */
+static struct driver_dir_entry bios_dir = {
+	.name = "bios",
+	.mode = (S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO),
+};
+
+struct edd_device {
+	char name[EDD_DEVICE_NAME_SIZE];
+	struct edd_info *info;
+	struct list_head node;
+	struct driver_dir_entry dir;
+};
+
+struct edd_attribute {
+	struct attribute attr;
+	ssize_t(*show) (struct edd_device * edev, char *buf, size_t count,
+			loff_t off);
+};
+
+/* forward declarations */
+static int edd_dev_is_type(struct edd_device *edev, const char *type);
+static struct pci_dev *edd_get_pci_dev(struct edd_device *edev);
+static struct scsi_device *edd_find_matching_scsi_device(struct edd_device *edev);
+
+static struct edd_device *edd_devices[EDDMAXNR];
+
+#define EDD_DEVICE_ATTR(_name,_mode,_show) \
+struct edd_attribute edd_attr_##_name = { 	\
+	.attr = {.name = __stringify(_name), .mode = _mode },	\
+	.show	= _show,				\
+};
+
+static inline struct edd_info *
+edd_dev_get_info(struct edd_device *edev)
+{
+	return edev->info;
+}
+static inline void
+edd_dev_set_info(struct edd_device *edev, struct edd_info *info)
+{
+	edev->info = info;
+}
+
+#define to_edd_attr(_attr) container_of(_attr,struct edd_attribute,attr)
+#define to_edd_device(_dir) container_of(_dir,struct edd_device,dir)
+
+static ssize_t
+edd_attr_show(struct driver_dir_entry *dir, struct attribute *attr,
+	      char *buf, size_t count, loff_t off)
+{
+	struct edd_device *dev = to_edd_device(dir);
+	struct edd_attribute *edd_attr = to_edd_attr(attr);
+	ssize_t ret = 0;
+
+	if (edd_attr->show)
+		ret = edd_attr->show(dev, buf, count, off);
+	return ret;
+}
+
+static struct driverfs_ops edd_attr_ops = {
+	.show = edd_attr_show,
+};
+
+static int
+edd_dump_raw_data(char *b, void *data, int length)
+{
+	char *orig_b = b;
+	char buffer1[80], buffer2[80], *b1, *b2, c;
+	unsigned char *p = data;
+	unsigned long column = 0;
+	int length_printed = 0;
+	const char maxcolumn = 16;
+	while (length_printed < length) {
+		b1 = buffer1;
+		b2 = buffer2;
+		for (column = 0;
+		     column < maxcolumn && length_printed < length; column++) {
+			b1 += sprintf(b1, "%02x ", (unsigned char) *p);
+			if (*p < 32 || *p > 126)
+				c = '.';
+			else
+				c = *p;
+			b2 += sprintf(b2, "%c", c);
+			p++;
+			length_printed++;
+		}
+		/* pad out the line */
+		for (; column < maxcolumn; column++) {
+			b1 += sprintf(b1, "   ");
+			b2 += sprintf(b2, " ");
+		}
+
+		b += sprintf(b, "%s\t%s\n", buffer1, buffer2);
+	}
+	return (b - orig_b);
+}
+
+static ssize_t
+edd_show_host_bus(struct edd_device *edev, char *buf, size_t count, loff_t off)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	char *p = buf;
+	int i;
+
+	if (!edev || !info || !buf || off) {
+		return 0;
+	}
+
+	for (i = 0; i < 4; i++) {
+		if (isprint(info->params.host_bus_type[i])) {
+			p += sprintf(p, "%c", info->params.host_bus_type[i]);
+		} else {
+			p += sprintf(p, " ");
+		}
+	}
+
+	if (!strncmp(info->params.host_bus_type, "ISA", 3)) {
+		p += sprintf(p, "\tbase_address: %x\n",
+			     info->params.interface_path.isa.base_address);
+	} else if (!strncmp(info->params.host_bus_type, "PCIX", 4) ||
+		   !strncmp(info->params.host_bus_type, "PCI", 3)) {
+		p += sprintf(p,
+			     "\t%02x:%02x.%01x  channel: %u\n",
+			     info->params.interface_path.pci.bus,
+			     info->params.interface_path.pci.slot,
+			     info->params.interface_path.pci.function,
+			     info->params.interface_path.pci.channel);
+	} else if (!strncmp(info->params.host_bus_type, "IBND", 4) ||
+		   !strncmp(info->params.host_bus_type, "XPRS", 4) ||
+		   !strncmp(info->params.host_bus_type, "HTPT", 4)) {
+		p += sprintf(p,
+			     "\tTBD: %llx\n",
+			     info->params.interface_path.ibnd.reserved);
+
+	} else {
+		p += sprintf(p, "\tunknown: %llx\n",
+			     info->params.interface_path.unknown.reserved);
+	}
+	return (p - buf);
+}
+
+static ssize_t
+edd_show_interface(struct edd_device *edev, char *buf, size_t count, loff_t off)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	char *p = buf;
+	int i;
+
+	if (!edev || !info || !buf || off) {
+		return 0;
+	}
+
+	for (i = 0; i < 8; i++) {
+		if (isprint(info->params.interface_type[i])) {
+			p += sprintf(p, "%c", info->params.interface_type[i]);
+		} else {
+			p += sprintf(p, " ");
+		}
+	}
+	if (!strncmp(info->params.interface_type, "ATAPI", 5)) {
+		p += sprintf(p, "\tdevice: %u  lun: %u\n",
+			     info->params.device_path.atapi.device,
+			     info->params.device_path.atapi.lun);
+	} else if (!strncmp(info->params.interface_type, "ATA", 3)) {
+		p += sprintf(p, "\tdevice: %u\n",
+			     info->params.device_path.ata.device);
+	} else if (!strncmp(info->params.interface_type, "SCSI", 4)) {
+		p += sprintf(p, "\tid: %u  lun: %llu\n",
+			     info->params.device_path.scsi.id,
+			     info->params.device_path.scsi.lun);
+	} else if (!strncmp(info->params.interface_type, "USB", 3)) {
+		p += sprintf(p, "\tserial_number: %llx\n",
+			     info->params.device_path.usb.serial_number);
+	} else if (!strncmp(info->params.interface_type, "1394", 4)) {
+		p += sprintf(p, "\teui: %llx\n",
+			     info->params.device_path.i1394.eui);
+	} else if (!strncmp(info->params.interface_type, "FIBRE", 5)) {
+		p += sprintf(p, "\twwid: %llx lun: %llx\n",
+			     info->params.device_path.fibre.wwid,
+			     info->params.device_path.fibre.lun);
+	} else if (!strncmp(info->params.interface_type, "I2O", 3)) {
+		p += sprintf(p, "\tidentity_tag: %llx\n",
+			     info->params.device_path.i2o.identity_tag);
+	} else if (!strncmp(info->params.interface_type, "RAID", 4)) {
+		p += sprintf(p, "\tidentity_tag: %x\n",
+			     info->params.device_path.raid.array_number);
+	} else if (!strncmp(info->params.interface_type, "SATA", 4)) {
+		p += sprintf(p, "\tdevice: %u\n",
+			     info->params.device_path.sata.device);
+	} else {
+		p += sprintf(p, "\tunknown: %llx %llx\n",
+			     info->params.device_path.unknown.reserved1,
+			     info->params.device_path.unknown.reserved2);
+	}
+
+	return (p - buf);
+}
+
+/**
+ * edd_show_raw_data() - unparses EDD information, returned to user-space
+ *
+ * Returns: number of bytes written, or 0 on failure
+ */
+static ssize_t
+edd_show_raw_data(struct edd_device *edev, char *buf, size_t count, loff_t off)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	int i, rc, warn_padding = 0, email = 0, nonzero_path = 0,
+		len = sizeof (*edd) - 4, found_pci=0;
+	uint8_t checksum = 0, c = 0;
+	char *p = buf;
+	struct pci_dev *pci_dev=NULL;
+	struct scsi_device *sd;
+	if (!edev || !info || !buf || off) {
+		return 0;
+	}
+
+	if (!(info->params.key == 0xBEDD || info->params.key == 0xDDBE))
+		len = info->params.length;
+
+	p += sprintf(p, "int13 fn48 returned data:\n\n");
+	p += edd_dump_raw_data(p, ((char *) edd) + 4, len);
+
+	/* Spec violation.  Adaptec AIC7899 returns 0xDDBE
+	   here, when it should be 0xBEDD.
+	 */
+	p += sprintf(p, "\n");
+	if (info->params.key == 0xDDBE) {
+		p += sprintf(p,
+			     "Warning: Spec violation.  Key should be 0xBEDD, is 0xDDBE\n");
+		email++;
+	}
+
+	if (!(info->params.key == 0xBEDD || info->params.key == 0xDDBE)) {
+		goto out;
+	}
+
+	for (i = 30; i <= 73; i++) {
+		c = *(((uint8_t *) edd) + i + 4);
+		if (c)
+			nonzero_path++;
+		checksum += c;
+	}
+
+	if (checksum) {
+		p += sprintf(p,
+			     "Warning: Spec violation.  Device Path checksum invalid.\n");
+		email++;
+	}
+
+	if (!nonzero_path) {
+		p += sprintf(p, "Error: Spec violation.  Empty device path.\n");
+		email++;
+		goto out;
+	}
+
+	for (i = 0; i < 4; i++) {
+		if (!isprint(info->params.host_bus_type[i])) {
+			warn_padding++;
+		}
+	}
+	for (i = 0; i < 8; i++) {
+		if (!isprint(info->params.interface_type[i])) {
+			warn_padding++;
+		}
+	}
+
+	if (warn_padding) {
+		p += sprintf(p,
+			     "Warning: Spec violation.  Padding should be 0x20.\n");
+		email++;
+	}
+
+	rc = edd_dev_is_type(edev, "PCI");
+	if (!rc) {
+		pci_dev = pci_find_slot(info->params.interface_path.pci.bus,
+					PCI_DEVFN(info->params.interface_path.
+						  pci.slot,
+						  info->params.interface_path.
+						  pci.function));
+		if (!pci_dev) {
+			p += sprintf(p, "Error: BIOS says this is a PCI device, but the OS doesn't know\n");
+			p += sprintf(p, "  about a PCI device at %02x:%02x.%01x\n",
+				     info->params.interface_path.pci.bus,
+				     info->params.interface_path.pci.slot,
+				     info->params.interface_path.pci.function);
+			email++;
+		}
+		else {
+			found_pci++;
+		}
+	}
+
+	if (found_pci) {
+		sd = edd_find_matching_scsi_device(edev);
+		if (!sd) {
+			p += sprintf(p, "Error: BIOS says this is a SCSI device, but\n");
+			p += sprintf(p, "  the OS doesn't know about this SCSI device.\n");
+			p += sprintf(p, "  Do you have it's driver module loaded?\n");
+			email++;
+		}
+	}
+
+out:
+	if (email) {
+		p += sprintf(p, "\nPlease check %s\n", REPORT_URL);
+		p += sprintf(p, "to see if this has been reported.  If not,\n");
+		p += sprintf(p, "please send the information requested there.\n");
+	}
+
+	return (p - buf);
+}
+
+static ssize_t
+edd_show_version(struct edd_device *edev, char *buf, size_t count, loff_t off)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	char *p = buf;
+	if (!edev || !info || !buf || off) {
+		return 0;
+	}
+
+	p += sprintf(p, "0x%02x\n", info->version);
+	return (p - buf);
+}
+
+static ssize_t
+edd_show_extensions(struct edd_device *edev, char *buf, size_t count,
+		    loff_t off)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	char *p = buf;
+	if (!edev || !info || !buf || off) {
+		return 0;
+	}
+
+	if (info->interface_support & EDD_EXT_FIXED_DISK_ACCESS) {
+		p += sprintf(p, "Fixed disk access\n");
+	}
+	if (info->interface_support & EDD_EXT_DEVICE_LOCKING_AND_EJECTING) {
+		p += sprintf(p, "Device locking and ejecting\n");
+	}
+	if (info->interface_support & EDD_EXT_ENHANCED_DISK_DRIVE_SUPPORT) {
+		p += sprintf(p, "Enhanced Disk Drive support\n");
+	}
+	if (info->interface_support & EDD_EXT_64BIT_EXTENSIONS) {
+		p += sprintf(p, "64-bit extensions\n");
+	}
+	return (p - buf);
+}
+
+static ssize_t
+edd_show_info_flags(struct edd_device *edev, char *buf, size_t count,
+		    loff_t off)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	char *p = buf;
+	if (!edev || !info || !buf || off) {
+		return 0;
+	}
+
+	if (info->params.info_flags & EDD_INFO_DMA_BOUNDRY_ERROR_TRANSPARENT)
+		p += sprintf(p, "DMA boundry error transparent\n");
+	if (info->params.info_flags & EDD_INFO_GEOMETRY_VALID)
+		p += sprintf(p, "geometry valid\n");
+	if (info->params.info_flags & EDD_INFO_REMOVABLE)
+		p += sprintf(p, "removable\n");
+	if (info->params.info_flags & EDD_INFO_WRITE_VERIFY)
+		p += sprintf(p, "write verify\n");
+	if (info->params.info_flags & EDD_INFO_MEDIA_CHANGE_NOTIFICATION)
+		p += sprintf(p, "media change notification\n");
+	if (info->params.info_flags & EDD_INFO_LOCKABLE)
+		p += sprintf(p, "lockable\n");
+	if (info->params.info_flags & EDD_INFO_NO_MEDIA_PRESENT)
+		p += sprintf(p, "no media present\n");
+	if (info->params.info_flags & EDD_INFO_USE_INT13_FN50)
+		p += sprintf(p, "use int13 fn50\n");
+	return (p - buf);
+}
+
+static ssize_t
+edd_show_default_cylinders(struct edd_device *edev, char *buf, size_t count,
+			   loff_t off)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	char *p = buf;
+	if (!edev || !info || !buf || off) {
+		return 0;
+	}
+
+	p += sprintf(p, "0x%x\n", info->params.num_default_cylinders);
+	return (p - buf);
+}
+
+static ssize_t
+edd_show_default_heads(struct edd_device *edev, char *buf, size_t count,
+		       loff_t off)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	char *p = buf;
+	if (!edev || !info || !buf || off) {
+		return 0;
+	}
+
+	p += sprintf(p, "0x%x\n", info->params.num_default_heads);
+	return (p - buf);
+}
+
+static ssize_t
+edd_show_default_sectors_per_track(struct edd_device *edev, char *buf,
+				   size_t count, loff_t off)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	char *p = buf;
+	if (!edev || !info || !buf || off) {
+		return 0;
+	}
+
+	p += sprintf(p, "0x%x\n", info->params.sectors_per_track);
+	return (p - buf);
+}
+
+static ssize_t
+edd_show_sectors(struct edd_device *edev, char *buf, size_t count, loff_t off)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	char *p = buf;
+	if (!edev || !info || !buf || off) {
+		return 0;
+	}
+
+	p += sprintf(p, "0x%llx\n", info->params.number_of_sectors);
+	return (p - buf);
+}
+
+static EDD_DEVICE_ATTR(raw_data, 0444, edd_show_raw_data);
+static EDD_DEVICE_ATTR(version, 0444, edd_show_version);
+static EDD_DEVICE_ATTR(extensions, 0444, edd_show_extensions);
+static EDD_DEVICE_ATTR(info_flags, 0444, edd_show_info_flags);
+static EDD_DEVICE_ATTR(default_cylinders, 0444, edd_show_default_cylinders);
+static EDD_DEVICE_ATTR(default_heads, 0444, edd_show_default_heads);
+static EDD_DEVICE_ATTR(default_sectors_per_track, 0444,
+		       edd_show_default_sectors_per_track);
+static EDD_DEVICE_ATTR(sectors, 0444, edd_show_sectors);
+static EDD_DEVICE_ATTR(interface, 0444, edd_show_interface);
+static EDD_DEVICE_ATTR(host_bus, 0444, edd_show_host_bus);
+
+/*
+ * Some device instances may not have all the above attributes,
+ * or the attribute values may be meaningless (i.e. if
+ * the device is < EDD 3.0, it won't have host_bus and interface
+ * information), so don't bother making files for them.  Likewise
+ * if the default_{cylinders,heads,sectors_per_track} values
+ * are zero, the BIOS doesn't provide sane values, don't bother
+ * creating files for them either.
+ *
+ * struct attr_test pairs an attribute and a test,
+ * (the default NULL test being true - the attribute exists)
+ * and individual existence tests may be written for each
+ * attribute.
+ */
+struct attr_test {
+	struct edd_attribute *attr;
+	int (*test) (struct edd_device * edev);
+};
+
+static int
+edd_has_default_cylinders(struct edd_device *edev)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	if (!edev || !info)
+		return 1;
+	return !info->params.num_default_cylinders;
+}
+
+static int
+edd_has_default_heads(struct edd_device *edev)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	if (!edev || !info)
+		return 1;
+	return !info->params.num_default_heads;
+}
+
+static int
+edd_has_default_sectors_per_track(struct edd_device *edev)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	if (!edev || !info)
+		return 1;
+	return !info->params.sectors_per_track;
+}
+
+static int
+edd_has_edd30(struct edd_device *edev)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	int i, nonzero_path = 0;
+	char c;
+
+	if (!edev || !info)
+		return 1;
+
+	if (!(info->params.key == 0xBEDD || info->params.key == 0xDDBE)) {
+		return 1;
+	}
+
+	for (i = 30; i <= 73; i++) {
+		c = *(((uint8_t *) edd) + i + 4);
+		if (c) {
+			nonzero_path++;
+			break;
+		}
+	}
+	if (!nonzero_path) {
+		return 1;
+	}
+
+	return 0;
+}
+
+static struct attr_test def_attrs[] = {
+	{.attr = &edd_attr_raw_data},
+	{.attr = &edd_attr_version},
+	{.attr = &edd_attr_extensions},
+	{.attr = &edd_attr_info_flags},
+	{.attr = &edd_attr_sectors},
+	{.attr = &edd_attr_default_cylinders,
+	 .test = &edd_has_default_cylinders},
+	{.attr = &edd_attr_default_heads,
+	 .test = &edd_has_default_heads},
+	{.attr = &edd_attr_default_sectors_per_track,
+	 .test = &edd_has_default_sectors_per_track},
+	{.attr = &edd_attr_interface,
+	 .test = &edd_has_edd30},
+	{.attr = &edd_attr_host_bus,
+	 .test = &edd_has_edd30},
+	{.attr = NULL,.test = NULL},
+};
+
+/* edd_get_devpath_length(), edd_fill_devpath(), and edd_device_link()
+   were taken from linux/drivers/base/fs/device.c.  When these
+   or similar are exported to generic code, remove these.
+*/
+
+static int
+edd_get_devpath_length(struct device *dev)
+{
+	int length = 1;
+	struct device *parent = dev;
+
+	/* walk up the ancestors until we hit the root.
+	 * Add 1 to strlen for leading '/' of each level.
+	 */
+	do {
+		length += strlen(parent->bus_id) + 1;
+		parent = parent->parent;
+	} while (parent);
+	return length;
+}
+
+static void
+edd_fill_devpath(struct device *dev, char *path, int length)
+{
+	struct device *parent;
+	--length;
+	for (parent = dev; parent; parent = parent->parent) {
+		int cur = strlen(parent->bus_id);
+
+		/* back up enough to print this bus id with '/' */
+		length -= cur;
+		strncpy(path + length, parent->bus_id, cur);
+		*(path + --length) = '/';
+	}
+}
+
+static int
+edd_device_symlink(struct edd_device *edev, struct device *dev, char *name)
+{
+	char *path;
+	int length;
+	int error = 0;
+
+	if (!dev->bus || !name)
+		return 0;
+
+	length = edd_get_devpath_length(dev);
+
+	/* now add the path from the edd_device directory
+	 * It should be '../..' (one to get to the 'bios' directory,
+	 * and one to get to the root of the fs.)
+	 */
+	length += strlen("../../root");
+
+	if (length > PATH_MAX)
+		return -ENAMETOOLONG;
+
+	if (!(path = kmalloc(length, GFP_KERNEL)))
+		return -ENOMEM;
+	memset(path, 0, length);
+
+	/* our relative position */
+	strcpy(path, "../../root");
+
+	edd_fill_devpath(dev, path, length);
+	error = driverfs_create_symlink(&edev->dir, name, path);
+	kfree(path);
+	return error;
+}
+
+/**
+ * edd_dev_is_type() - is this EDD device a 'type' device?
+ * @edev
+ * @type - a host bus or interface identifier string per the EDD spec
+ *
+ * Returns 0 if it is a 'type' device, nonzero otherwise.
+ */
+static int
+edd_dev_is_type(struct edd_device *edev, const char *type)
+{
+	int rc;
+	struct edd_info *info = edd_dev_get_info(edev);
+	if (!edev || !info)
+		return 1;
+
+	rc = strncmp(info->params.host_bus_type, type, strlen(type));
+	if (!rc)
+		return 0;
+
+	return strncmp(info->params.interface_type, type, strlen(type));
+}
+
+/**
+ * edd_get_pci_dev() - finds pci_dev that matches edev
+ * @edev - edd_device
+ *
+ * Returns pci_dev if found, or NULL
+ */
+static struct pci_dev *
+edd_get_pci_dev(struct edd_device *edev)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+	int rc;
+
+	rc = edd_dev_is_type(edev, "PCI");
+	if (rc)
+		return NULL;
+
+	return pci_find_slot(info->params.interface_path.pci.bus,
+			     PCI_DEVFN(info->params.interface_path.pci.slot,
+				       info->params.interface_path.pci.
+				       function));
+}
+
+static int
+edd_create_symlink_to_pcidev(struct edd_device *edev)
+{
+
+	struct pci_dev *pci_dev = edd_get_pci_dev(edev);
+	if (!pci_dev)
+		return 1;
+	return edd_device_symlink(edev, &pci_dev->dev, "pci_dev");
+}
+
+/**
+ * edd_match_scsidev()
+ * @edev - EDD device is a known SCSI device
+ * @sd - scsi_device with host who's parent is a PCI controller
+ * 
+ * returns 0 on success, 1 on failure
+ */
+static int
+edd_match_scsidev(struct edd_device *edev, struct scsi_device *sd)
+{
+	struct edd_info *info = edd_dev_get_info(edev);
+
+	if (!edev || !sd || !info)
+		return 1;
+
+	if ((sd->channel == info->params.interface_path.pci.channel) &&
+	    (sd->id == info->params.device_path.scsi.id) &&
+	    (sd->lun == info->params.device_path.scsi.lun)) {
+		return 0;
+	}
+
+	return 1;
+}
+
+/**
+ * edd_find_matching_device()
+ * @edev - edd_device to match
+ *
+ * Returns struct scsi_device * on success,
+ * or NULL on failure.
+ * This assumes that all children of the PCI controller
+ * are scsi_hosts, and that all children of scsi_hosts
+ * are scsi_devices.
+ * The reference counting probably isn't the best it could be.
+ */
+
+#define	to_scsi_host(d)	\
+	container_of(d, struct Scsi_Host, host_driverfs_dev)
+#define children_to_dev(n) container_of(n,struct device,node)
+static struct scsi_device *
+edd_find_matching_scsi_device(struct edd_device *edev)
+{
+	struct list_head *shost_node, *sdev_node;
+	int rc = 1;
+	struct scsi_device *sd = NULL;
+	struct device *shost_dev, *sdev_dev;
+	struct pci_dev *pci_dev;
+	struct Scsi_Host *sh;
+
+	rc = edd_dev_is_type(edev, "SCSI");
+	if (rc)
+		return NULL;
+
+	pci_dev = edd_get_pci_dev(edev);
+	if (!pci_dev)
+		return NULL;
+
+	get_device(&pci_dev->dev);
+
+	list_for_each(shost_node, &pci_dev->dev.children) {
+		shost_dev = children_to_dev(shost_node);
+		get_device(shost_dev);
+		sh = to_scsi_host(shost_dev);
+
+		list_for_each(sdev_node, &shost_dev->children) {
+			sdev_dev = children_to_dev(sdev_node);
+			get_device(sdev_dev);
+			sd = to_scsi_device(sdev_dev);
+			rc = edd_match_scsidev(edev, sd);
+			put_device(sdev_dev);
+			if (!rc)
+				break;
+		}
+		put_device(shost_dev);
+		if (!rc)
+			break;
+	}
+
+	put_device(&pci_dev->dev);
+	if (!rc)
+		return sd;
+	return NULL;
+}
+
+static int
+edd_create_symlink_to_scsidev(struct edd_device *edev)
+{
+
+	struct scsi_device *sdev;
+	struct pci_dev *pci_dev;
+	struct edd_info *info = edd_dev_get_info(edev);
+	int rc;
+
+	rc = edd_dev_is_type(edev, "PCI");
+	if (rc)
+		return rc;
+
+	pci_dev = pci_find_slot(info->params.interface_path.pci.bus,
+				PCI_DEVFN(info->params.interface_path.pci.slot,
+					  info->params.interface_path.pci.
+					  function));
+	if (!pci_dev)
+		return 1;
+
+	sdev = edd_find_matching_scsi_device(edev);
+	if (!sdev)
+		return 1;
+
+	get_device(&sdev->sdev_driverfs_dev);
+	rc = edd_device_symlink(edev, &sdev->sdev_driverfs_dev, "disc");
+	put_device(&sdev->sdev_driverfs_dev);
+
+	return rc;
+}
+
+static inline int
+edd_create_file(struct edd_device *edev, struct edd_attribute *attr)
+{
+	return driverfs_create_file(&attr->attr, &edev->dir);
+}
+
+static inline void
+edd_device_unregister(struct edd_device *edev)
+{
+	driverfs_remove_file(&edev->dir, "pci_dev");
+	driverfs_remove_file(&edev->dir, "disc");
+	driverfs_remove_dir(&edev->dir);
+	list_del_init(&edev->node);
+}
+
+static int
+edd_populate_dir(struct edd_device *edev)
+{
+	struct attr_test *s;
+	int i;
+	int error = 0;
+
+	for (i = 0; def_attrs[i].attr; i++) {
+		s = &def_attrs[i];
+		if (!s->test || (s->test && !s->test(edev))) {
+			if ((error = edd_create_file(edev, s->attr))) {
+				break;
+			}
+		}
+	}
+
+	if (error)
+		return error;
+
+	edd_create_symlink_to_pcidev(edev);
+	edd_create_symlink_to_scsidev(edev);
+
+	return 0;
+}
+
+static int
+edd_make_dir(struct edd_device *edev)
+{
+	int error;
+
+	edev->dir.name = edev->name;
+	edev->dir.mode = (S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
+	edev->dir.ops = &edd_attr_ops;
+
+	error = driverfs_create_dir(&edev->dir, &bios_dir);
+	if (!error)
+		error = edd_populate_dir(edev);
+	return error;
+}
+
+static int
+edd_device_register(struct edd_device *edev, int i)
+{
+	int error;
+
+	if (!edev)
+		return 1;
+	memset(edev, 0, sizeof (*edev));
+	edd_dev_set_info(edev, &edd[i]);
+	snprintf(edev->name, EDD_DEVICE_NAME_SIZE, "int13_dev%02x",
+		 edd[i].device);
+	error = edd_make_dir(edev);
+	return error;
+}
+
+/**
+ * edd_init() - creates driverfs tree of EDD data
+ *
+ * This assumes that eddnr and edd were
+ * assigned in setup.c already.
+ */
+static int __init
+edd_init(void)
+{
+	unsigned int i;
+	int rc;
+	struct edd_device *edev;
+
+	printk(KERN_INFO "BIOS EDD facility v%s, %d devices found\n",
+	       EDD_VERSION, eddnr);
+
+	if (!eddnr) {
+		printk(KERN_INFO "EDD information not available.\n");
+		return 1;
+	}
+
+	rc = driverfs_create_dir(&bios_dir, NULL);
+	if (rc)
+		return rc;
+
+	for (i = 0; i < eddnr && i < EDDMAXNR && !rc; i++) {
+		edev = kmalloc(sizeof (*edev), GFP_KERNEL);
+		if (!edev)
+			return -ENOMEM;
+
+		rc = edd_device_register(edev, i);
+		if (rc) {
+			kfree(edev);
+			break;
+		}
+		edd_devices[i] = edev;
+	}
+
+	if (rc) {
+		driverfs_remove_dir(&bios_dir);
+		return rc;
+	}
+
+	return 0;
+}
+
+static void __exit
+edd_exit(void)
+{
+	int i;
+	struct edd_device *edev;
+
+	for (i = 0; i < eddnr && i < EDDMAXNR; i++) {
+		if ((edev = edd_devices[i])) {
+			edd_device_unregister(edev);
+			kfree(edev);
+		}
+	}
+
+	driverfs_remove_dir(&bios_dir);
+}
+
+late_initcall(edd_init);
+module_exit(edd_exit);

arch/i386/kernel/i386_ksyms.c

@@ -29,6 +29,7 @@
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
+#include <asm/edd.h>
 
 extern void dump_thread(struct pt_regs *, struct user *);
 extern spinlock_t rtc_lock;
@@ -182,3 +183,8 @@ extern int is_sony_vaio_laptop;
 EXPORT_SYMBOL(is_sony_vaio_laptop);
 
 EXPORT_SYMBOL(__PAGE_KERNEL);
+
+#ifdef CONFIG_EDD_MODULE
+EXPORT_SYMBOL(edd);
+EXPORT_SYMBOL(eddnr);
+#endif

arch/i386/kernel/setup.c

@@ -36,6 +36,7 @@
 #include <linux/highmem.h>
 #include <asm/e820.h>
 #include <asm/mpspec.h>
+#include <asm/edd.h>
 #include <asm/setup.h>
 #include <asm/arch_hooks.h>
 #include "setup_arch_pre.h"
@@ -466,6 +467,22 @@ static int __init copy_e820_map(struct e820entry * biosmap, int nr_map)
 	return 0;
 }
 
+#if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
+unsigned char eddnr;
+struct edd_info edd[EDDNR];
+/**
+ * copy_edd() - Copy the BIOS EDD information into a safe place.
+ *
+ */
+static inline void copy_edd(void)
+{
+     eddnr = EDD_NR;
+     memcpy(edd, EDD_BUF, sizeof(edd));
+}
+#else
+#define copy_edd() do {} while (0)
+#endif
+
 /*
  * Do NOT EVER look at the BIOS memory size location.
  * It does not work on many machines.
@@ -843,6 +860,7 @@ void __init setup_arch(char **cmdline_p)
 #endif
 	ARCH_SETUP
 	setup_memory_region();
+	copy_edd();
 
 	if (!MOUNT_ROOT_RDONLY)
 		root_mountflags &= ~MS_RDONLY;

include/asm-i386/edd.h

+/*
+ * linux/include/asm-i386/edd.h
+ *  Copyright (C) 2002 Dell Computer Corporation
+ *  by Matt Domsch <Matt_Domsch@dell.com>
+ *
+ * structures and definitions for the int 13h, ax={41,48}h
+ * BIOS Enhanced Disk Drive Services
+ * This is based on the T13 group document D1572 Revision 0 (August 14 2002)
+ * available at http://www.t13.org/docs2002/d1572r0.pdf.  It is
+ * very similar to D1484 Revision 3 http://www.t13.org/docs2002/d1484r3.pdf
+ *
+ * In a nutshell, arch/i386/boot/setup.S populates a scratch table
+ * in the empty_zero_block that contains a list of BIOS-enumerated
+ * boot devices.
+ * In arch/i386/kernel/setup.c, this information is
+ * transferred into the edd structure, and in arch/i386/kernel/edd.c, that
+ * information is used to identify BIOS boot disk.  The code in setup.S
+ * is very sensitive to the size of these structures.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License v2.0 as published by
+ * the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#ifndef _ASM_I386_EDD_H
+#define _ASM_I386_EDD_H
+
+#define EDDNR 0x1e9		/* addr of number of edd_info structs at EDDBUF
+				   in empty_zero_block - treat this as 1 byte  */
+#define EDDBUF	0x600		/* addr of edd_info structs in empty_zero_block */
+#define EDDMAXNR 6		/* number of edd_info structs starting at EDDBUF  */
+#define EDDEXTSIZE 4		/* change these if you muck with the structures */
+#define EDDPARMSIZE 74
+
+#ifndef __ASSEMBLY__
+
+#define EDD_EXT_FIXED_DISK_ACCESS           (1 << 0)
+#define EDD_EXT_DEVICE_LOCKING_AND_EJECTING (1 << 1)
+#define EDD_EXT_ENHANCED_DISK_DRIVE_SUPPORT (1 << 2)
+#define EDD_EXT_64BIT_EXTENSIONS            (1 << 3)
+
+#define EDD_INFO_DMA_BOUNDRY_ERROR_TRANSPARENT (1 << 0)
+#define EDD_INFO_GEOMETRY_VALID                (1 << 1)
+#define EDD_INFO_REMOVABLE                     (1 << 2)
+#define EDD_INFO_WRITE_VERIFY                  (1 << 3)
+#define EDD_INFO_MEDIA_CHANGE_NOTIFICATION     (1 << 4)
+#define EDD_INFO_LOCKABLE                      (1 << 5)
+#define EDD_INFO_NO_MEDIA_PRESENT              (1 << 6)
+#define EDD_INFO_USE_INT13_FN50                (1 << 7)
+
+struct edd_device_params {
+	u16 length;
+	u16 info_flags;
+	u32 num_default_cylinders;
+	u32 num_default_heads;
+	u32 sectors_per_track;
+	u64 number_of_sectors;
+	u16 bytes_per_sector;
+	u32 dpte_ptr;		/* 0xFFFFFFFF for our purposes */
+	u16 key;		/* = 0xBEDD */
+	u8 device_path_info_length;	/* = 44 */
+	u8 reserved2;
+	u16 reserved3;
+	u8 host_bus_type[4];
+	u8 interface_type[8];
+	union {
+		struct {
+			u16 base_address;
+			u16 reserved1;
+			u32 reserved2;
+		} __attribute__ ((packed)) isa;
+		struct {
+			u8 bus;
+			u8 slot;
+			u8 function;
+			u8 channel;
+			u32 reserved;
+		} __attribute__ ((packed)) pci;
+		/* pcix is same as pci */
+		struct {
+			u64 reserved;
+		} __attribute__ ((packed)) ibnd;
+		struct {
+			u64 reserved;
+		} __attribute__ ((packed)) xprs;
+		struct {
+			u64 reserved;
+		} __attribute__ ((packed)) htpt;
+		struct {
+			u64 reserved;
+		} __attribute__ ((packed)) unknown;
+	} interface_path;
+	union {
+		struct {
+			u8 device;
+			u8 reserved1;
+			u16 reserved2;
+			u32 reserved3;
+			u64 reserved4;
+		} __attribute__ ((packed)) ata;
+		struct {
+			u8 device;
+			u8 lun;
+			u8 reserved1;
+			u8 reserved2;
+			u32 reserved3;
+			u64 reserved4;
+		} __attribute__ ((packed)) atapi;
+		struct {
+			u16 id;
+			u64 lun;
+			u16 reserved1;
+			u32 reserved2;
+		} __attribute__ ((packed)) scsi;
+		struct {
+			u64 serial_number;
+			u64 reserved;
+		} __attribute__ ((packed)) usb;
+		struct {
+			u64 eui;
+			u64 reserved;
+		} __attribute__ ((packed)) i1394;
+		struct {
+			u64 wwid;
+			u64 lun;
+		} __attribute__ ((packed)) fibre;
+		struct {
+			u64 identity_tag;
+			u64 reserved;
+		} __attribute__ ((packed)) i2o;
+		struct {
+			u32 array_number;
+			u32 reserved1;
+			u64 reserved2;
+		} __attribute((packed)) raid;
+		struct {
+			u8 device;
+			u8 reserved1;
+			u16 reserved2;
+			u32 reserved3;
+			u64 reserved4;
+		} __attribute__ ((packed)) sata;
+		struct {
+			u64 reserved1;
+			u64 reserved2;
+		} __attribute__ ((packed)) unknown;
+	} device_path;
+	u8 reserved4;
+	u8 checksum;
+} __attribute__ ((packed));
+
+struct edd_info {
+	u8 device;
+	u8 version;
+	u16 interface_support;
+	struct edd_device_params params;
+} __attribute__ ((packed));
+
+extern struct edd_info edd[EDDNR];
+extern unsigned char eddnr;
+#endif				/*!__ASSEMBLY__ */
+
+#endif				/* _ASM_I386_EDD_H */

include/asm-i386/setup.h

@@ -37,6 +37,8 @@
 #define KERNEL_START (*(unsigned long *) (PARAM+0x214))
 #define INITRD_START (*(unsigned long *) (PARAM+0x218))
 #define INITRD_SIZE (*(unsigned long *) (PARAM+0x21c))
+#define EDD_NR     (*(unsigned char *) (PARAM+EDDNR))
+#define EDD_BUF     ((struct edd_info *) (PARAM+EDDBUF))
 #define COMMAND_LINE ((char *) (PARAM+2048))
 #define COMMAND_LINE_SIZE 256