[Xen-devel] Xen-arm patch to early init_uart in head.S

[Lars Rasmusson <lars.rasmusson@xxxxxxxxx>]

Hi,

reading the PL011 UART documentation on
http://infocenter.arm.com/help/topic/com.arm.doc.ddi0183f/DDI0183.pdf

the early initialisation of the UART on the Versatile Express
is incorrect. (Currently it probably works only because the default
values are sane.)

Cheers,
/Lars

From 7184ce113d907ce8cf366dddbe8145e59987a656 Mon Sep 17 00:00:00 2001
From: Lars Rasmusson <Lars.Rasmusson@xxxxxxx>
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@xxxxxxx>
---
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

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