[PATCH 3/3] ARM: early_printk: use printascii() rather than printch()

[Nicolas Pitre]

On Tue, 31 Oct 2017, Russell King - ARM Linux wrote:
> On Tue, Oct 31, 2017 at 02:15:14PM -0400, Nicolas Pitre wrote:
> > On Tue, 31 Oct 2017, Russell King - ARM Linux wrote:
> > > So a printch('\n') produces "\n\r" on the UART.  If we're fixing
> > > printascii() to emit "\r\n" instead of "\n\r" for a '\n', then
> > > printch() should have the same fix, and should not truncate to
> > > just '\n'.
> > 
> > OK... That's easy to achieve, but is it desirable?
> 
> Yes - remember, these are supposed to be usable from assembly,
> and we really don't want to have the complexity of:
> 
> 	mov	r0, #'\r'
> 	bl	printch
> 	mov	r0, #'\n'
> 	bl	printch
> 
> each time we want to begin a new line.

Fine with me.

diff --git a/arch/arm/kernel/debug.S b/arch/arm/kernel/debug.S
index ea9646cc2a..01d746efff 100644
--- a/arch/arm/kernel/debug.S
+++ b/arch/arm/kernel/debug.S
@@ -79,25 +79,28 @@ hexbuf:		.space 16
 
 ENTRY(printascii)
 		addruart_current r3, r1, r2
-		b	2f
-1:		waituart r2, r3
-		senduart r1, r3
-		busyuart r2, r3
-		teq	r1, #'\n'
-		moveq	r1, #'\r'
-		beq	1b
-2:		teq	r0, #0
+1:		teq	r0, #0
 		ldrneb	r1, [r0], #1
 		teqne	r1, #0
-		bne	1b
-		ret	lr
+		reteq	lr
+2:		teq     r1, #'\n'
+		bne	3f
+		mov	r1, '\r'
+		waituart r2, r3
+		senduart r1, r3
+		busyuart r2, r3
+		mov	r1, '\n'
+3:		waituart r2, r3
+		senduart r1, r3
+		busyuart r2, r3
+		b	1b
 ENDPROC(printascii)
 
 ENTRY(printch)
 		addruart_current r3, r1, r2
 		mov	r1, r0
 		mov	r0, #0
-		b	1b
+		b	2b
 ENDPROC(printch)
 
 #ifdef CONFIG_MMU