memdisk: correct the types for the EDD DPT, and write a real onesyslinux-3.83-pre5

Fix the sizes of some of the fields in the EDD DPT.  Write a real one
to the best of our ability.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

2 files changed, 41 insertions, 27 deletions

diff --git a/memdisk/memdisk.inc b/memdisk/memdisk.inc
index b4d45c44..cfba2dfc 100644
--- a/memdisk/memdisk.inc
+++ b/memdisk/memdisk.inc
@@ -945,12 +945,6 @@ Mover_dst2:	db 0			; High 8 bits of source addy
 Mover_dummy2:	dd 0, 0, 0, 0		; More space for the BIOS
 
 		alignb 4, db 0
-Stack		dd 0			; Saved SS:ESP on invocation
-		dw 0
-SavedAX		dw 0			; AX saved on invocation
-Recursive	dw 0			; Recursion counter
-
-		alignb 4, db 0
 MemDisk_Info	equ $			; Pointed to by installation check
 MDI_Bytes	dw MDI_Len		; Total bytes in MDI structure
 MDI_Version	db VERSION_MINOR, VERSION_MAJOR	; MEMDISK version
@@ -1008,21 +1002,26 @@ EDD_DPT:
 .totalsize	dd 0, 0			; Filled in by installer
 .bytespersec	dw SECTORSIZE
 .eddtable	dw -1, -1		; Invalid DPTE pointer
-.dpikey		dw 0			; Device Path Info magic (not impl.)
-					; Would be 0beddh if implemented
+.dpikey		dw 0BEDDh		; Device Path Info magic
 .dpilen		db 2ch			; DPI len
 .res1		db 0			; Reserved
-.res2		db 0			; Reserved
-.bustype	equ 'PCI '		; Host bus type (4 bytes, space padded)
-.inttype	equ 'ATA     '		; Interface type (8 bytes, spc. padded)
+.res2		dw 0			; Reserved
+.bustype	equ 'MEM '		; Host bus type (4 bytes, space padded)
+.inttype	equ 'MEMORY  '		; Interface type (8 bytes, spc. padded)
 .intpath	dd 0, 0			; Interface path
 .devpath	dd 0, 0, 0, 0		; Device path
 .res3		db 0			; Reserved
-.chksum		db 0			; DPI checksum (not implemented)
+.chksum		db 0			; DPI checksum
 
 %endif
 
 		; End patch area
+		alignb 4, db 0
+Stack		dd 0			; Saved SS:ESP on invocation
+		dw 0
+SavedAX		dw 0			; AX saved on invocation
+Recursive	dw 0			; Recursion counter
+
 		alignb 4, db 0		; We *MUST* end on a dword boundary
 
 E820Table	equ $			; The installer loads the E820 table here
diff --git a/memdisk/setup.c b/memdisk/setup.c
index 7af16108..013f3dfa 100644
--- a/memdisk/setup.c
+++ b/memdisk/setup.c
@@ -81,8 +81,9 @@ struct edd_dpt {
     uint16_t bytespersec;	/* Bytes/sector */
     uint16_t dpte_off, dpte_seg;	/* DPTE pointer */
     uint16_t dpikey;		/* Device Path Info magic */
+    uint8_t  dpilen;		/* Device Path Info length */
     uint8_t  res1;		/* Reserved */
-    uint8_t  res2;		/* Reserved */
+    uint16_t res2;		/* Reserved */
     uint8_t  bustype[4];	/* Host bus type */
     uint8_t  inttype[8];	/* Interface type */
     uint64_t intpath;		/* Interface path */
@@ -717,6 +718,17 @@ static void relocate_rm_code(uint32_t newbase)
     sti();
 }
 
+static uint8_t checksum_buf(const void *buf, int count)
+{
+    const uint8_t *p = buf;
+    uint8_t c;
+
+    while (count--)
+	c += *p++;
+
+    return c;
+}
+
 #define STACK_NEEDED	512	/* Number of bytes of stack */
 
 struct real_mode_args rm_args;
@@ -896,20 +908,23 @@ void setup(const struct real_mode_args *rm_args_ptr)
 
     /* Set up an EDD drive parameter table */
     if (do_edd) {
-      pptr->edd_dpt.sectors = geometry->sectors;
-      /* The EDD spec has this as <= 15482880  sectors (1024x240x63);
-	 this seems to make very little sense.  Try for something saner. */
-      if (geometry->c <= 1024 && geometry->h <= 255 && geometry->s <= 63) {
-	pptr->edd_dpt.c = geometry->c;
-	pptr->edd_dpt.h = geometry->h;
-	pptr->edd_dpt.s = geometry->s;
-	pptr->edd_dpt.flags |= 0x0002;	/* Geometry valid */
-      }
-      if (!(geometry->driveno & 0x80)) {
-	/* Floppy drive.  Mark it as a removable device with
-	   media change notification; media is present. */
-	pptr->edd_dpt.flags |= 0x0014;
-      }
+	pptr->edd_dpt.sectors = geometry->sectors;
+	/* The EDD spec has this as <= 15482880  sectors (1024x240x63);
+	   this seems to make very little sense.  Try for something saner. */
+	if (geometry->c <= 1024 && geometry->h <= 255 && geometry->s <= 63) {
+	    pptr->edd_dpt.c = geometry->c;
+	    pptr->edd_dpt.h = geometry->h;
+	    pptr->edd_dpt.s = geometry->s;
+	    pptr->edd_dpt.flags |= 0x0002;	/* Geometry valid */
+	}
+	if (!(geometry->driveno & 0x80)) {
+	    /* Floppy drive.  Mark it as a removable device with
+	       media change notification; media is present. */
+	    pptr->edd_dpt.flags |= 0x0014;
+	}
+	
+	pptr->edd_dpt.devpath[0] = pptr->diskbuf;
+	pptr->edd_dpt.chksum  = -checksum_buf(&pptr->edd_dpt.dpikey, 73-30);
     }
 
     /* The size is given by hptr->total_size plus the size of the E820