[src/trunk]: src/sys/arch/sparc/sparc Explicitly clear AUXIO4M_FTC bit in FTC...

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

details:   https://anonhg.NetBSD.org/src/rev/48fe4f9faa83
branches:  trunk
changeset: 750765:48fe4f9faa83
user:      tsutsui <tsutsui%NetBSD.org@localhost>
date:      Wed Jan 13 12:43:06 2010 +0000

description:
Explicitly clear AUXIO4M_FTC bit in FTC_FLIP macro used on
pseudo-dma for floppy, as well as AUXIO4C_FTC bit for sun4c.
A comment in the macro says AUXIO4M_FTC bit is auto-clear,
but my two SS20s (including compatible) with 150MHz hyperSPARCs
get data_overrun without it, and no bad side effect on SS5
(works with and without this change).

Closes PR port-sparc/42516, which is the last one of a bunch of
floppy issue on NetBSD/sparc since NetBSD 2.0 days. See
http://mail-index.NetBSD.org/port-sparc/2009/12/20/msg000484.html
for details.

diffstat:

 sys/arch/sparc/sparc/auxreg.h |  5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diffs (19 lines):

diff -r e19e05b257dc -r 48fe4f9faa83 sys/arch/sparc/sparc/auxreg.h
--- a/sys/arch/sparc/sparc/auxreg.h     Wed Jan 13 12:18:55 2010 +0000
+++ b/sys/arch/sparc/sparc/auxreg.h     Wed Jan 13 12:43:06 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: auxreg.h,v 1.12 2005/11/16 03:00:23 uwe Exp $ */
+/*     $NetBSD: auxreg.h,v 1.13 2010/01/13 12:43:06 tsutsui Exp $ */
 
 /*
  * Copyright (c) 1992, 1993
@@ -105,6 +105,9 @@
        if (CPU_ISSUN4M) {                                              \
                /* AUXIO4M_FTC bit is auto-clear */                     \
                *AUXIO4M_REG = auxio_regval | AUXIO4M_FTC;              \
+               /* XXX we need to clear it on hyperSPARC SS20 */        \
+               DELAY(10);                                              \
+               *AUXIO4M_REG = auxio_regval;                            \
        } else {                                                        \
                auxio_regval |= AUXIO4C_FTC;                            \
                *AUXIO4C_REG = auxio_regval;                            \