patch-2.4.23 linux-2.4.23/arch/i386/boot/setup.S

• Lines: 90
• Date: 2003-11-28 10:26:19.000000000 -0800
• Orig file: linux-2.4.22/arch/i386/boot/setup.S
• Orig date: 2002-08-02 17:39:42.000000000 -0700

diff -urN linux-2.4.22/arch/i386/boot/setup.S linux-2.4.23/arch/i386/boot/setup.S
@@ -45,6 +45,10 @@
  * 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> October 2002
+ * conformant to T13 Committee www.t13.org
+ *   projects 1572D, 1484D, 1386D, 1226DT
  */
 
 #include <linux/config.h>
@@ -53,6 +57,7 @@
 #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 +548,70 @@
 done_apm_bios:
 #endif
 
+#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
+       						# 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	$CHECKEXTENSIONSPRESENT, %ah    # Function 41
+	movw	$EDDMAGIC1, %bx			# magic
+	int	$0x13				# make the call
+	jc	edd_done			# no more BIOS devices
+
+    	cmpw	$EDDMAGIC2, %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	$GETDEVICEPARAMETERS, %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