Date: Mon, 2 Apr 2001 11:27:33 +0100 (BST) From: Doug Rabson <dfr@nlsystems.com> To: Mike Smith <msmith@freebsd.org> Cc: Michael Richards <michael@fastmail.ca>, <freebsd-alpha@FreeBSD.ORG>, <mjacob@feral.com> Subject: Re: Proposed Loader fix Message-ID: <Pine.BSF.4.33.0104021125160.5113-100000@herring.nlsystems.com> In-Reply-To: <200104020705.f3275IC08101@mass.dis.org>
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On Mon, 2 Apr 2001, Mike Smith wrote:
> > My proposed solution is:
> > Modify the devsw struct. Here is the original:
> ...
> > This appears to carry info about the device. So I say that I should
> > be able to add a flag to it so it will not be opened multiple times.
>
> Don't do this. Try adding some caching to libalpha so that it doesn't
> open the prom device more than once. Since we only need one handle (SRM
> doesn't support more than one device), once we've got one, we can always
> reuse it.
How about something like this (untested) patch. I'm not entirely happy
with it since it will never call prom_close and I remember having problems
with ncr hardware not probing properly if we didn't close it in the
loader. Possibly an 'open count' or similar would suffice.
Index: srmdisk.c
===================================================================
RCS file: /home/ncvs/src/sys/boot/alpha/libalpha/srmdisk.c,v
retrieving revision 1.9
diff -u -r1.9 srmdisk.c
--- srmdisk.c 2000/03/15 01:53:34 1.9
+++ srmdisk.c 2001/04/02 10:22:17
@@ -96,6 +96,7 @@
int bd_unit; /* SRM unit number */
int bd_namelen;
int bd_flags;
+ int bd_fd;
} bdinfo [MAXBDDEV];
static int nbdinfo = 0;
@@ -113,6 +114,7 @@
ret.bits = prom_getenv(PROM_E_BOOTED_DEV,
bdinfo[0].bd_name, sizeof(bdinfo[0].bd_name));
bdinfo[0].bd_namelen = ret.u.retval;
+ bdinfo[0].bd_fd = -1;
nbdinfo++;
return (0);
@@ -155,7 +157,7 @@
struct disklabel *lp;
int sector, slice, i;
int error;
- int unit;
+ int unit, fd;
prom_return_t ret;
va_start(args, f);
@@ -169,11 +171,16 @@
}
/* Call the prom to open the disk. */
- ret.bits = prom_open(bdinfo[unit].bd_name, bdinfo[unit].bd_namelen);
- if (ret.u.status == 2)
- return (ENXIO);
- if (ret.u.status == 3)
- return (EIO);
+ if (bdinfo[unit].bd_fd < 0) {
+ ret.bits = prom_open(bdinfo[unit].bd_name, bdinfo[unit].bd_namelen);
+ if (ret.u.status == 2)
+ return (ENXIO);
+ if (ret.u.status == 3)
+ return (EIO);
+ bdinfo[unit].bd_fd = fd = ret.u.retval;
+ } else {
+ fd = bdinfo[unit].bd_fd;
+ }
od = (struct open_disk *) malloc(sizeof(struct open_disk));
if (!od) {
@@ -182,7 +189,7 @@
}
/* Look up SRM unit number, intialise open_disk structure */
- od->od_fd = ret.u.retval;
+ od->od_fd = fd;
od->od_unit = dev->d_kind.srmdisk.unit;
od->od_flags = bdinfo[od->od_unit].bd_flags;
od->od_boff = 0;
@@ -321,7 +328,9 @@
{
struct open_disk *od = f->f_devdata;
+#if 0
(void)prom_close(od->od_fd);
+#endif
free(od);
f->f_devdata = NULL;
--
Doug Rabson Mail: dfr@nlsystems.com
Phone: +44 20 8348 6160
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