[PATCH 3/3] ARM: early_printk: use printascii() rather than printch()
Chris Brandt
Chris.Brandt at renesas.com
Tue Oct 31 12:12:32 PDT 2017
On Tuesday, October 31, 2017, Nicolas Pitre wrote:
> 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
This patch worked for me.
I get my carriage returns again.
Thanks.
Chris
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