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Work around UMC8669F and Startech UART bugs by not writing to the

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divisor latch registers if the registers wouldn't change.

Use the default console cfcr setting while setting the divisor
latch registers for console i/o.  Input may be messed up by
transiently changing the cfcr.

Use a usual cfcr setting while setting the divisor latch registers
in the probe.  This shouldn't matter, but this is not the place to
test the UART's handling of 5 bit words.

Removed a stale devfs comment.
This commit is contained in:
Bruce Evans 1996-09-30 12:22:27 +00:00
parent edbfbd9280
commit 92d0aa20dc
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=18575
3 changed files with 108 additions and 33 deletions
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47
sys/dev/sio/sio.c
View File

@ -31,7 +31,7 @@
* SUCH DAMAGE.
*
* from: @(#)com.c 7.5 (Berkeley) 5/16/91
* $Id: sio.c,v 1.145 1996/09/06 23:08:05 phk Exp $
* $Id: sio.c,v 1.146 1996/09/14 04:27:42 bde Exp $
*/
#include "opt_comconsole.h"
@ -569,7 +569,7 @@ sioprobe(dev)
* XXX what about the UART bug avoided by waiting in comparam()?
* We don't want to to wait long enough to drain at 2 bps.
*/
outb(iobase + com_cfcr, CFCR_DLAB);
outb(iobase + com_cfcr, CFCR_DLAB | CFCR_8BITS);
outb(iobase + com_dlbl, COMBRD(9600) & 0xff);
outb(iobase + com_dlbh, (u_int) COMBRD(9600) >> 8);
outb(iobase + com_cfcr, CFCR_8BITS);
@ -942,7 +942,6 @@ determined_type: ;
dev = makedev(CDEV_MAJOR, 0);
cdevsw_add(&dev, &sio_cdevsw, NULL);
#ifdef DEVFS
/* devsw, minor, type, uid, gid, perm, fmt, ... */
com->devfs_token_ttyd = devfs_add_devswf(&sio_cdevsw,
unit, DV_CHR,
UID_ROOT, GID_WHEEL, 0600, "ttyd%n", unit);
@ -1826,6 +1825,8 @@ comparam(tp, t)
int cflag;
struct com_s *com;
int divisor;
u_char dlbh;
u_char dlbl;
int error;
Port_t iobase;
int s;
@ -1937,8 +1938,18 @@ comparam(tp, t)
if (divisor != 0) {
outb(iobase + com_cfcr, cfcr | CFCR_DLAB);
outb(iobase + com_dlbl, divisor & 0xFF);
outb(iobase + com_dlbh, (u_int) divisor >> 8);
/*
* Only set the divisor registers if they would change,
* since on some 16550 incompatibles (UMC8669F), setting
* them while input is arriving them loses sync until
* data stops arriving.
*/
dlbl = divisor & 0xFF;
if (inb(iobase + com_dlbl) != dlbl)
outb(iobase + com_dlbl, dlbl);
dlbh = (u_int) divisor >> 8;
if (inb(iobase + com_dlbh) != dlbh)
outb(iobase + com_dlbh, dlbh);
}
outb(iobase + com_cfcr, com->cfcr_image = cfcr);
if (!(tp->t_state & TS_TTSTOP))
@ -2322,6 +2333,8 @@ siocnopen(sp)
struct siocnstate *sp;
{
int divisor;
u_char dlbh;
u_char dlbl;
Port_t iobase;
/*
@ -2334,12 +2347,22 @@ siocnopen(sp)
outb(iobase + com_ier, 0); /* spltty() doesn't stop siointr() */
siocntxwait();
sp->cfcr = inb(iobase + com_cfcr);
outb(iobase + com_cfcr, CFCR_DLAB);
outb(iobase + com_cfcr, CFCR_DLAB | CFCR_8BITS);
sp->dlbl = inb(iobase + com_dlbl);
sp->dlbh = inb(iobase + com_dlbh);
/*
* Only set the divisor registers if they would change, since on
* some 16550 incompatibles (Startech), setting them clears the
* data input register. This also reduces the effects of the
* UMC8669F bug.
*/
divisor = ttspeedtab(comdefaultrate, comspeedtab);
outb(iobase + com_dlbl, divisor & 0xFF);
outb(iobase + com_dlbh, (u_int) divisor >> 8);
dlbl = divisor & 0xFF;
if (sp->dlbl != dlbl)
outb(iobase + com_dlbl, dlbl);
dlbh = (u_int) divisor >> 8;
if (sp->dlbh != dlbh)
outb(iobase + com_dlbh, dlbh);
outb(iobase + com_cfcr, CFCR_8BITS);
sp->mcr = inb(iobase + com_mcr);
/*
@ -2361,9 +2384,11 @@ siocnclose(sp)
*/
siocntxwait();
iobase = siocniobase;
outb(iobase + com_cfcr, CFCR_DLAB);
outb(iobase + com_dlbl, sp->dlbl);
outb(iobase + com_dlbh, sp->dlbh);
outb(iobase + com_cfcr, CFCR_DLAB | CFCR_8BITS);
if (sp->dlbl != inb(iobase + com_dlbl))
outb(iobase + com_dlbl, sp->dlbl);
if (sp->dlbh != inb(iobase + com_dlbh))
outb(iobase + com_dlbh, sp->dlbh);
outb(iobase + com_cfcr, sp->cfcr);
/*
* XXX damp oscillations of MCR_DTR and MCR_RTS by not restoring them.

47
sys/i386/isa/sio.c
View File

@ -31,7 +31,7 @@
* SUCH DAMAGE.
*
* from: @(#)com.c 7.5 (Berkeley) 5/16/91
* $Id: sio.c,v 1.145 1996/09/06 23:08:05 phk Exp $
* $Id: sio.c,v 1.146 1996/09/14 04:27:42 bde Exp $
*/
#include "opt_comconsole.h"
@ -569,7 +569,7 @@ sioprobe(dev)
* XXX what about the UART bug avoided by waiting in comparam()?
* We don't want to to wait long enough to drain at 2 bps.
*/
outb(iobase + com_cfcr, CFCR_DLAB);
outb(iobase + com_cfcr, CFCR_DLAB | CFCR_8BITS);
outb(iobase + com_dlbl, COMBRD(9600) & 0xff);
outb(iobase + com_dlbh, (u_int) COMBRD(9600) >> 8);
outb(iobase + com_cfcr, CFCR_8BITS);
@ -942,7 +942,6 @@ determined_type: ;
dev = makedev(CDEV_MAJOR, 0);
cdevsw_add(&dev, &sio_cdevsw, NULL);
#ifdef DEVFS
/* devsw, minor, type, uid, gid, perm, fmt, ... */
com->devfs_token_ttyd = devfs_add_devswf(&sio_cdevsw,
unit, DV_CHR,
UID_ROOT, GID_WHEEL, 0600, "ttyd%n", unit);
@ -1826,6 +1825,8 @@ comparam(tp, t)
int cflag;
struct com_s *com;
int divisor;
u_char dlbh;
u_char dlbl;
int error;
Port_t iobase;
int s;
@ -1937,8 +1938,18 @@ comparam(tp, t)
if (divisor != 0) {
outb(iobase + com_cfcr, cfcr | CFCR_DLAB);
outb(iobase + com_dlbl, divisor & 0xFF);
outb(iobase + com_dlbh, (u_int) divisor >> 8);
/*
* Only set the divisor registers if they would change,
* since on some 16550 incompatibles (UMC8669F), setting
* them while input is arriving them loses sync until
* data stops arriving.
*/
dlbl = divisor & 0xFF;
if (inb(iobase + com_dlbl) != dlbl)
outb(iobase + com_dlbl, dlbl);
dlbh = (u_int) divisor >> 8;
if (inb(iobase + com_dlbh) != dlbh)
outb(iobase + com_dlbh, dlbh);
}
outb(iobase + com_cfcr, com->cfcr_image = cfcr);
if (!(tp->t_state & TS_TTSTOP))
@ -2322,6 +2333,8 @@ siocnopen(sp)
struct siocnstate *sp;
{
int divisor;
u_char dlbh;
u_char dlbl;
Port_t iobase;
/*
@ -2334,12 +2347,22 @@ siocnopen(sp)
outb(iobase + com_ier, 0); /* spltty() doesn't stop siointr() */
siocntxwait();
sp->cfcr = inb(iobase + com_cfcr);
outb(iobase + com_cfcr, CFCR_DLAB);
outb(iobase + com_cfcr, CFCR_DLAB | CFCR_8BITS);
sp->dlbl = inb(iobase + com_dlbl);
sp->dlbh = inb(iobase + com_dlbh);
/*
* Only set the divisor registers if they would change, since on
* some 16550 incompatibles (Startech), setting them clears the
* data input register. This also reduces the effects of the
* UMC8669F bug.
*/
divisor = ttspeedtab(comdefaultrate, comspeedtab);
outb(iobase + com_dlbl, divisor & 0xFF);
outb(iobase + com_dlbh, (u_int) divisor >> 8);
dlbl = divisor & 0xFF;
if (sp->dlbl != dlbl)
outb(iobase + com_dlbl, dlbl);
dlbh = (u_int) divisor >> 8;
if (sp->dlbh != dlbh)
outb(iobase + com_dlbh, dlbh);
outb(iobase + com_cfcr, CFCR_8BITS);
sp->mcr = inb(iobase + com_mcr);
/*
@ -2361,9 +2384,11 @@ siocnclose(sp)
*/
siocntxwait();
iobase = siocniobase;
outb(iobase + com_cfcr, CFCR_DLAB);
outb(iobase + com_dlbl, sp->dlbl);
outb(iobase + com_dlbh, sp->dlbh);
outb(iobase + com_cfcr, CFCR_DLAB | CFCR_8BITS);
if (sp->dlbl != inb(iobase + com_dlbl))
outb(iobase + com_dlbl, sp->dlbl);
if (sp->dlbh != inb(iobase + com_dlbh))
outb(iobase + com_dlbh, sp->dlbh);
outb(iobase + com_cfcr, sp->cfcr);
/*
* XXX damp oscillations of MCR_DTR and MCR_RTS by not restoring them.

47
sys/isa/sio.c
View File

@ -31,7 +31,7 @@
* SUCH DAMAGE.
*
* from: @(#)com.c 7.5 (Berkeley) 5/16/91
* $Id: sio.c,v 1.145 1996/09/06 23:08:05 phk Exp $
* $Id: sio.c,v 1.146 1996/09/14 04:27:42 bde Exp $
*/
#include "opt_comconsole.h"
@ -569,7 +569,7 @@ sioprobe(dev)
* XXX what about the UART bug avoided by waiting in comparam()?
* We don't want to to wait long enough to drain at 2 bps.
*/
outb(iobase + com_cfcr, CFCR_DLAB);
outb(iobase + com_cfcr, CFCR_DLAB | CFCR_8BITS);
outb(iobase + com_dlbl, COMBRD(9600) & 0xff);
outb(iobase + com_dlbh, (u_int) COMBRD(9600) >> 8);
outb(iobase + com_cfcr, CFCR_8BITS);
@ -942,7 +942,6 @@ determined_type: ;
dev = makedev(CDEV_MAJOR, 0);
cdevsw_add(&dev, &sio_cdevsw, NULL);
#ifdef DEVFS
/* devsw, minor, type, uid, gid, perm, fmt, ... */
com->devfs_token_ttyd = devfs_add_devswf(&sio_cdevsw,
unit, DV_CHR,
UID_ROOT, GID_WHEEL, 0600, "ttyd%n", unit);
@ -1826,6 +1825,8 @@ comparam(tp, t)
int cflag;
struct com_s *com;
int divisor;
u_char dlbh;
u_char dlbl;
int error;
Port_t iobase;
int s;
@ -1937,8 +1938,18 @@ comparam(tp, t)
if (divisor != 0) {
outb(iobase + com_cfcr, cfcr | CFCR_DLAB);
outb(iobase + com_dlbl, divisor & 0xFF);
outb(iobase + com_dlbh, (u_int) divisor >> 8);
/*
* Only set the divisor registers if they would change,
* since on some 16550 incompatibles (UMC8669F), setting
* them while input is arriving them loses sync until
* data stops arriving.
*/
dlbl = divisor & 0xFF;
if (inb(iobase + com_dlbl) != dlbl)
outb(iobase + com_dlbl, dlbl);
dlbh = (u_int) divisor >> 8;
if (inb(iobase + com_dlbh) != dlbh)
outb(iobase + com_dlbh, dlbh);
}
outb(iobase + com_cfcr, com->cfcr_image = cfcr);
if (!(tp->t_state & TS_TTSTOP))
@ -2322,6 +2333,8 @@ siocnopen(sp)
struct siocnstate *sp;
{
int divisor;
u_char dlbh;
u_char dlbl;
Port_t iobase;
/*
@ -2334,12 +2347,22 @@ siocnopen(sp)
outb(iobase + com_ier, 0); /* spltty() doesn't stop siointr() */
siocntxwait();
sp->cfcr = inb(iobase + com_cfcr);
outb(iobase + com_cfcr, CFCR_DLAB);
outb(iobase + com_cfcr, CFCR_DLAB | CFCR_8BITS);
sp->dlbl = inb(iobase + com_dlbl);
sp->dlbh = inb(iobase + com_dlbh);
/*
* Only set the divisor registers if they would change, since on
* some 16550 incompatibles (Startech), setting them clears the
* data input register. This also reduces the effects of the
* UMC8669F bug.
*/
divisor = ttspeedtab(comdefaultrate, comspeedtab);
outb(iobase + com_dlbl, divisor & 0xFF);
outb(iobase + com_dlbh, (u_int) divisor >> 8);
dlbl = divisor & 0xFF;
if (sp->dlbl != dlbl)
outb(iobase + com_dlbl, dlbl);
dlbh = (u_int) divisor >> 8;
if (sp->dlbh != dlbh)
outb(iobase + com_dlbh, dlbh);
outb(iobase + com_cfcr, CFCR_8BITS);
sp->mcr = inb(iobase + com_mcr);
/*
@ -2361,9 +2384,11 @@ siocnclose(sp)
*/
siocntxwait();
iobase = siocniobase;
outb(iobase + com_cfcr, CFCR_DLAB);
outb(iobase + com_dlbl, sp->dlbl);
outb(iobase + com_dlbh, sp->dlbh);
outb(iobase + com_cfcr, CFCR_DLAB | CFCR_8BITS);
if (sp->dlbl != inb(iobase + com_dlbl))
outb(iobase + com_dlbl, sp->dlbl);
if (sp->dlbh != inb(iobase + com_dlbh))
outb(iobase + com_dlbh, sp->dlbh);
outb(iobase + com_cfcr, sp->cfcr);
/*
* XXX damp oscillations of MCR_DTR and MCR_RTS by not restoring them.