From: Milton Miller <miltonm@bga.com>
Date: Tue, 6 Sep 2005 01:55:00 +0000 (+1000)
Subject: [PATCH] ppc64: Clean up CR handling
X-Git-Tag: v2.6.14-rc1~747^2~21
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=cb14c4d641b4e083fae7ce4a0e8a3973cecb7554;p=linux-2.6-omap-h63xx.git

[PATCH] ppc64: Clean up CR handling

Make the 16550 and real mode 16550 use tail recursion like the scc code
instead of repeating the routine except for the character sent.

Gcc recoginizes the tail recursion and handles it efficently without
stack allocations.  The maple real putc shrinks from 188 to 104 bytes
of instructions.  udbg_putc drops from 188 to 140 bytes.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
---

diff --git a/arch/ppc64/kernel/udbg.c b/arch/ppc64/kernel/udbg.c
index c0da45540f0..155670a40c3 100644
--- a/arch/ppc64/kernel/udbg.c
+++ b/arch/ppc64/kernel/udbg.c
@@ -169,12 +169,8 @@ void udbg_maple_real_putc(unsigned char c)
 		while ((real_readb(&udbg_comport->lsr) & LSR_THRE) == 0)
 			/* wait for idle */;
 		real_writeb(c, &udbg_comport->thr); eieio();
-		if (c == '\n') {
-			/* Also put a CR.  This is for convenience. */
-			while ((real_readb(&udbg_comport->lsr) & LSR_THRE) == 0)
-				/* wait for idle */;
-			real_writeb('\r', &udbg_comport->thr); eieio();
-		}
+		if (c == '\n')
+			udbg_maple_real_putc('\r');
 	}
 }
 
@@ -194,12 +190,8 @@ void udbg_putc(unsigned char c)
 		while ((in_8(&udbg_comport->lsr) & LSR_THRE) == 0)
 			/* wait for idle */;
 		out_8(&udbg_comport->thr, c);
-		if (c == '\n') {
-			/* Also put a CR.  This is for convenience. */
-			while ((in_8(&udbg_comport->lsr) & LSR_THRE) == 0)
-				/* wait for idle */; 
-			out_8(&udbg_comport->thr, '\r');
-		}
+		if (c == '\n')
+			udbg_putc('\r');
 	}
 #ifdef CONFIG_PPC_PMAC
 	else if (sccc) {