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* [PATCH] Set register values and comment in early init_uart to match documentation of PL011 UART
@ 2013-01-10 20:02 lra
  0 siblings, 0 replies; 3+ messages in thread
From: lra @ 2013-01-10 20:02 UTC (permalink / raw)
  To: xen-devel; +Cc: Lars Rasmusson

From: Lars Rasmusson <Lars.Rasmusson@sics.se>

Reading the PL011 UART documentation on
http://infocenter.arm.com/help/topic/com.arm.doc.ddi0183f/DDI0183.pdf
in sec 3.2 shows the early initialisation of the UART on the Versatile Express
is incorrect. (Currently it probably works only because the default
values are sane.)

Signed-off-by: Lars Rasmusson <Lars.Rasmusson@sics.se>
---
 xen/arch/arm/head.S |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/head.S b/xen/arch/arm/head.S
index cdbe011..a884592 100644
--- a/xen/arch/arm/head.S
+++ b/xen/arch/arm/head.S
@@ -291,11 +291,11 @@ fail:	PRINT("- Boot failed -\r\n")
  * Clobbers r0-r2 */
 init_uart:
 	mov   r1, #0x0
-	str   r1, [r11, #0x24]       /* -> UARTIBRD (Baud divisor fraction) */
+	str   r1, [r11, #0x28]       /* -> UARTFBRD (Baud divisor fraction) */
 	mov   r1, #0x4               /* 7.3728MHz / 0x4 == 16 * 115200 */
 	str   r1, [r11, #0x24]       /* -> UARTIBRD (Baud divisor integer) */
 	mov   r1, #0x60              /* 8n1 */
-	str   r1, [r11, #0x24]       /* -> UARTLCR_H (Line control) */
+	str   r1, [r11, #0x2C]       /* -> UARTLCR_H (Line control) */
 	ldr   r1, =0x00000301        /* RXE | TXE | UARTEN */
 	str   r1, [r11, #0x30]       /* -> UARTCR (Control Register) */
 	adr   r0, 1f
-- 
1.7.9.5

^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: Xen-arm patch to early init_uart in head.S
@ 2013-01-17 13:19 Ian Campbell
  2013-01-17 14:08 ` [PATCH] Set register values and comment in early init_uart to match documentation of PL011 UART lra
  0 siblings, 1 reply; 3+ messages in thread
From: Ian Campbell @ 2013-01-17 13:19 UTC (permalink / raw)
  To: lra@sics.se; +Cc: xen-devel@lists.xensource.com

On Fri, 2013-01-11 at 10:03 +0000, Ian Campbell wrote:
> On Thu, 2013-01-10 at 19:18 +0000, lra@sics.se wrote:
> > Hi,
> > 
> > reading the PL011 UART documentation on
> > http://infocenter.arm.com/help/topic/com.arm.doc.ddi0183f/DDI0183.pdf
> > 
> > I noticed the early initialisation of the UART on the Versatile Express
> > is incorrect. (Currently it probably works only because the default
> > values are sane.)
> 
> Good catch! Thanks.
> 
> > From 7184ce113d907ce8cf366dddbe8145e59987a656 Mon Sep 17 00:00:00 2001
> > From: Lars Rasmusson <Lars.Rasmusson@sics.se>
> > Date: Thu, 10 Jan 2013 17:10:44 +0100
> > Subject: [PATCH] Fixed register values and comment in early init_uart to
> > match documentation of PL011 UART
> > 
> > Signed-off-by: Lars Rasmusson <Lars.Rasmusson@sics.se>
> 
> Acked-by: Ian Campbell <ian.campbell@citrix.com>

I'm afraid this patch doesn't apply, I think it is based on a tree prior
to moving head.S -> arm32/head.S and fixing up the whitespace.

Could you rebase please?

Thanks,
Ian.

^ permalink raw reply	[flat|nested] 3+ messages in thread
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2013-01-17 13:19 Xen-arm patch to early init_uart in head.S Ian Campbell
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