Commit fa0900a4 authored by Matt Domsch's avatar Matt Domsch

Merge dell.com:/home/mdomsch/bk/linux-2.5

into dell.com:/home/mdomsch/bk/linux-2.5-edd-tolinus
parents d8c084f9 c6fe3db5
......@@ -46,8 +46,9 @@
* by Robert Schwebel, December 2001 <robert@schwebel.de>
*
* BIOS Enhanced Disk Drive support
* by Matt Domsch <Matt_Domsch@dell.com> September 2002
*
* by Matt Domsch <Matt_Domsch@dell.com> October 2002
* conformant to T13 Committee www.t13.org
* projects 1572D, 1484D, 1386D, 1226DT
*/
#include <linux/config.h>
......@@ -549,6 +550,27 @@ done_apm_bios:
#if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
# Do the BIOS Enhanced Disk Drive calls
# This consists of two calls:
# int 13h ah=41h "Check Extensions Present"
# int 13h ah=48h "Get Device Parameters"
#
# A buffer of size EDDMAXNR*(EDDEXTSIZE+EDDPARMSIZE) is reserved for our use
# in the empty_zero_page at EDDBUF. The first four bytes of which are
# used to store the device number, interface support map and version
# results from fn41. The following 74 bytes are used to store
# the results from fn48. Starting from device 80h, fn41, then fn48
# are called and their results stored in EDDBUF+n*(EDDEXTSIZE+EDDPARMIZE).
# Then the pointer is incremented to store the data for the next call.
# This repeats until either a device doesn't exist, or until EDDMAXNR
# devices have been stored.
# The one tricky part is that ds:si always points four bytes into
# the structure, and the fn41 results are stored at offsets
# from there. This removes the need to increment the pointer for
# every store, and leaves it ready for the fn48 call.
# A second one-byte buffer, EDDNR, in the empty_zero_page stores
# the number of BIOS devices which exist, up to EDDMAXNR.
# In setup.c, copy_edd() stores both empty_zero_page buffers away
# for later use, as they would get overwritten otherwise.
# This code is sensitive to the size of the structs in edd.h
edd_start:
# %ds points to the bootsector
......@@ -559,12 +581,12 @@ edd_start:
movb $0x80, %dl # BIOS device 0x80
edd_check_ext:
movb $0x41, %ah # Function 41
movw $0x55aa, %bx # magic
movb $CHECKEXTENSIONSPRESENT, %ah # Function 41
movw $EDDMAGIC1, %bx # magic
int $0x13 # make the call
jc edd_done # no more BIOS devices
cmpw $0xAA55, %bx # is magic right?
cmpw $EDDMAGIC2, %bx # is magic right?
jne edd_next # nope, next...
movb %dl, %ds:-4(%si) # store device number
......@@ -574,7 +596,7 @@ edd_check_ext:
edd_get_device_params:
movw $EDDPARMSIZE, %ds:(%si) # put size
movb $0x48, %ah # Function 48
movb $GETDEVICEPARAMETERS, %ah # Function 48
int $0x13 # make the call
# Don't check for fail return
# it doesn't matter.
......
This diff is collapsed.
......@@ -471,7 +471,8 @@ static int __init copy_e820_map(struct e820entry * biosmap, int nr_map)
unsigned char eddnr;
struct edd_info edd[EDDNR];
/**
* copy_edd() - Copy the BIOS EDD information into a safe place.
* copy_edd() - Copy the BIOS EDD information
* from empty_zero_page into a safe place.
*
*/
static inline void copy_edd(void)
......
......@@ -36,6 +36,10 @@
#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
#define CHECKEXTENSIONSPRESENT 0x41
#define GETDEVICEPARAMETERS 0x48
#define EDDMAGIC1 0x55AA
#define EDDMAGIC2 0xAA55
#ifndef __ASSEMBLY__
......
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