[src/trunk]: src/sys/arch/i386/stand/lib fix some disk handling problems intr...

[drochner <drochner%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/32c56a2129e6
branches:  trunk
changeset: 467886:32c56a2129e6
user:      drochner <drochner%NetBSD.org@localhost>
date:      Tue Mar 30 17:55:48 1999 +0000

description:
fix some disk handling problems introduced in the last commits:
-read retries were botched, use the right sector count
-read-ahead buffer was effectively unused
-concentrate the handling of the weird BIOS geometry report at one place
-fallback for old floppies left cylinder count uninitialized

diffstat:

 sys/arch/i386/stand/lib/bios_disk.S   |  31 +++++++++-----------------
 sys/arch/i386/stand/lib/biosdisk_ll.c |  41 +++++++++++++++++++---------------
 2 files changed, 34 insertions(+), 38 deletions(-)

diffs (178 lines):

diff -r dfc7aed3b4d0 -r 32c56a2129e6 sys/arch/i386/stand/lib/bios_disk.S
--- a/sys/arch/i386/stand/lib/bios_disk.S       Tue Mar 30 17:34:55 1999 +0000
+++ b/sys/arch/i386/stand/lib/bios_disk.S       Tue Mar 30 17:55:48 1999 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: bios_disk.S,v 1.5 1999/03/08 00:09:25 fvdl Exp $       */
+/*     $NetBSD: bios_disk.S,v 1.6 1999/03/30 17:55:48 drochner Exp $   */
 
 /*
  * Ported to boot 386BSD by Julian Elischer (julian%tfs.com@localhost) Sept 1992
@@ -114,7 +114,8 @@
 
 /*
 #
-# get_diskinfo():  takes a pointer to a biosdisk_ll struct, and fills it in.
+# get_diskinfo():  return a word that represents the
+#      max number of sectors, heads and cylinders for this device
 #
 */
 
@@ -128,9 +129,7 @@
        push    %esi
        push    %edi
 
-       movl    8(%ebp), %esi           # diskinfo(drive #)
-       movb    (%esi), %dl
-       pushl   %esi
+       movb    8(%ebp), %dl            # diskinfo(drive #)
 
        call    _C_LABEL(prot_to_real)  # enter real mode
 
@@ -146,7 +145,7 @@
 #      subb    %ah, %ah                # %ax = 0
 #      movb    %ah, %bh                # %bh = 0
 #      movb    $2, %bl                 # %bl bits 0-3 = drive type, 2 = 1.2M
-#      movb    $79, %ch                # max track
+       movb    $79, %ch                # max track
        movb    $15, %cl                # max sector
        movb    $1, %dh                 # max head
 #      movb    $1, %dl                 # # floppy drives installed
@@ -154,23 +153,15 @@
        # carry = 0
 
 ok:
+       /* form a longword representing all this gunk */
+       shll    $8, %ecx
+       movb    %dh, %cl
+
        data32
        call    _C_LABEL(real_to_prot)  # back to protected mode
 
-       popl    %esi
-
-       movzbl  %dh, %eax
-       movl    %eax, 8(%esi)           # heads
-       movb    %cl, %al
-       andb    $0x3f, %al
-       movzbl  %al, %ebx
-       movl    %ebx, 4(%esi)           # sectors per track
-       xorl    %eax, %eax
-       movb    %ch, %al
-       andl    $0x0c0, %ecx
-       shll    $2, %ecx
-       orl     %ecx, %eax
-       movl    %eax, 12(%esi)          # cylinders
+       data32
+       movl    %ecx, %eax
 
        pop     %edi
        pop     %esi
diff -r dfc7aed3b4d0 -r 32c56a2129e6 sys/arch/i386/stand/lib/biosdisk_ll.c
--- a/sys/arch/i386/stand/lib/biosdisk_ll.c     Tue Mar 30 17:34:55 1999 +0000
+++ b/sys/arch/i386/stand/lib/biosdisk_ll.c     Tue Mar 30 17:55:48 1999 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: biosdisk_ll.c,v 1.6 1999/03/08 00:09:25 fvdl Exp $      */
+/*     $NetBSD: biosdisk_ll.c,v 1.7 1999/03/30 17:55:49 drochner Exp $  */
 
 /*
  * Copyright (c) 1996
@@ -47,16 +47,21 @@
 
 extern long ourseg;
 
-extern void get_diskinfo __P((struct biosdisk_ll *));
+extern int get_diskinfo __P((int));
 extern void int13_getextinfo __P((int, struct biosdisk_ext13info *));
 extern int int13_extension __P((int));
 extern int biosread __P((int, int, int, int, int, char *));
 extern int biosextread __P((int, void *));
 static int do_read __P((struct biosdisk_ll *, int, int, char *));
 
-#define        SPT(di)         ((di)&0xff)
-#define        HEADS(di)       ((((di)>>8)&0xff)+1)
-#define CYL(di)                
+/*
+ * we get from get_diskinfo():
+ * xxxx  %ch  %cl  %dh (registers after int13/8), ie
+ * xxxx cccc Csss hhhh
+ */
+#define        SPT(di)         (((di)>>8)&0x3f)
+#define        HEADS(di)       (((di)&0xff)+1)
+#define CYL(di)                (((((di)>>16)&0xff)|(((di)>>6)&0x300))+1)
 
 #ifndef BIOSDISK_RETRIES
 #define BIOSDISK_RETRIES 5
@@ -67,12 +72,15 @@
        struct biosdisk_ll *d;
        struct biosdisk_ext13info *ed;
 {
-       d->sec = d->head = 0;
+       int diskinfo;
 
-       get_diskinfo(d);
+       diskinfo = get_diskinfo(d->dev);
+       d->sec = SPT(diskinfo);
+       d->head = HEADS(diskinfo);
+       d->cyl = CYL(diskinfo);
 
        d->flags = 0;
-       if ((d->dev&0x80) && int13_extension(d->dev)) {
+       if ((d->dev & 0x80) && int13_extension(d->dev)) {
                d->flags |= BIOSDISK_EXT13;
                if (ed != NULL)
                        int13_getextinfo(d->dev, ed);
@@ -82,7 +90,7 @@
         * get_diskinfo assumes floppy if BIOS call fails. Check at least
         * "valid" geometry.
         */
-       return (!d->sec || !d->head || !d->cyl);
+       return (!d->sec || !d->head);
 }
 
 /*
@@ -124,7 +132,7 @@
 
                return ext.cnt;
        } else {
-               spc = (d->head  + 1) * d->sec;
+               spc = d->head * d->sec;
                cyl = dblk / spc;
                head = (dblk % spc) / d->sec;
                sec = dblk % d->sec;
@@ -157,22 +165,21 @@
 
                        /* no, read from disk */
                        char           *trbuf;
+                       int maxsecs;
                        int retries = BIOSDISK_RETRIES;
 
-                       nsec = num;
-
                        if (cold) {
                                /* transfer directly to buffer */
                                trbuf = buf;
+                               maxsecs = num;
                        } else {
                                /* fill read-ahead buffer */
                                trbuf = diskbuf;
-                               if (nsec > RA_SECTORS)
-                                       nsec = RA_SECTORS;
-
+                               maxsecs = RA_SECTORS;
+                               diskbuf_user = 0; /* not yet valid */
                        }
 
-                       while ((nsec = do_read(d, dblk, nsec, trbuf)) < 0) {
+                       while ((nsec = do_read(d, dblk, maxsecs, trbuf)) < 0) {
 #ifdef DISK_DEBUG
                                if (!cold)
                                        printf("read error C:%d H:%d S:%d-%d\n",
@@ -180,8 +187,6 @@
 #endif
                                if (--retries >= 0)
                                        continue;
-                               if (!cold)
-                                       diskbuf_user = 0; /* mark invalid */
                                return (-1);    /* XXX cannot output here if
                                                 * (cold) */
                        }