Cleaned up initialization of hardware flow control for 16650As. Use

defined values instead of hard-coded values.  Don't repeat the register
access part of the code 4 times times or triple-space statements.  This
fixes half of the style bugs in rev.1.172.

Hardware flow control of 16650As is still officially unsupported.  I
was mistaken about it being broken.  It is broken in 16650s but is
fixed in 16650As except for the maximum trigger level (which is no
longer used).  Testing of the 16650's broken hardware flow control
watermarks by programming them on 16950s showed that their effects are
not too bad if the fifo size and trigger level are reasonably large
(16 is much better than 8).

1 files changed, 11 insertions, 25 deletions

diff --git a/sys/dev/sio/sio.c b/sys/dev/sio/sio.c
index 916f5dd..4fa8ef7 100644
--- a/sys/dev/sio/sio.c
+++ b/sys/dev/sio/sio.c
@@ -2205,6 +2205,7 @@ comparam(tp, t)
 	u_int		divisor;
 	u_char		dlbh;
 	u_char		dlbl;
+	u_char		efr_flowbits;
 	int		s;
 	int		unit;
 
@@ -2309,18 +2310,13 @@ comparam(tp, t)
 			sio_setreg(com, com_dlbh, dlbh);
 	}
 
-	sio_setreg(com, com_cfcr, com->cfcr_image = cfcr);
-
 	if (!(tp->t_state & TS_TTSTOP))
 		com->state |= CS_TTGO;
+	efr_flowbits = 0;
 
 	if (cflag & CRTS_IFLOW) {
-		if (com->st16650a) {
-			sio_setreg(com, com_cfcr, 0xbf);
-			sio_setreg(com, com_fifo,
-				   sio_getreg(com, com_fifo) | 0x40);
-		}
 		com->state |= CS_RTS_IFLOW;
+		efr_flowbits |= EFR_AUTORTS;
 		/*
 		 * If CS_RTS_IFLOW just changed from off to on, the change
 		 * needs to be propagated to MCR_RTS.  This isn't urgent,
@@ -2334,14 +2330,8 @@ comparam(tp, t)
 		 * on here, since comstart() won't do it later.
 		 */
 		outb(com->modem_ctl_port, com->mcr_image |= MCR_RTS);
-		if (com->st16650a) {
-			sio_setreg(com, com_cfcr, 0xbf);
-			sio_setreg(com, com_fifo,
-				   sio_getreg(com, com_fifo) & ~0x40);
-		}
 	}
 
-
 	/*
 	 * Set up state to handle output flow control.
 	 * XXX - worth handling MDMBUF (DCD) flow control at the lowest level?
@@ -2351,22 +2341,18 @@ comparam(tp, t)
 	com->state &= ~CS_CTS_OFLOW;
 	if (cflag & CCTS_OFLOW) {
 		com->state |= CS_CTS_OFLOW;
+		efr_flowbits |= EFR_AUTOCTS;
 		if (!(com->last_modem_status & MSR_CTS))
 			com->state &= ~CS_ODEVREADY;
-		if (com->st16650a) {
-			sio_setreg(com, com_cfcr, 0xbf);
-			sio_setreg(com, com_fifo,
-				   sio_getreg(com, com_fifo) | 0x80);
-		}
-	} else {
-		if (com->st16650a) {
-			sio_setreg(com, com_cfcr, 0xbf);
-			sio_setreg(com, com_fifo,
-				   sio_getreg(com, com_fifo) & ~0x80);
-		}
 	}
 
-	sio_setreg(com, com_cfcr, com->cfcr_image);
+	if (com->st16650a) {
+		sio_setreg(com, com_lcr, LCR_EFR_ENABLE);
+		sio_setreg(com, com_efr,
+			   (sio_getreg(com, com_efr)
+			    & ~(EFR_AUTOCTS | EFR_AUTORTS)) | efr_flowbits);
+	}
+	sio_setreg(com, com_cfcr, com->cfcr_image = cfcr);
 
 	/* XXX shouldn't call functions while intrs are disabled. */
 	disc_optim(tp, t, com);