From 130645eee340608c12b632535d3f983508348ba1 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Fri, 24 May 2013 15:47:27 +0200 Subject: arm/early-printk: allow skipping of UART init While it seems obvious to initialize the UART before using it, chances are that some firmware code or the bootloader already did this. So it may actually be a good idea to skip the initialization, in fact this fixes early printk on my TC2 Versatile Express. So provide an option in xen/arch/arm/Rules.mk to only initialize the UART when needed. Signed-off-by: Andre Przywara Reviewed-by: Julien Grall Acked-by: Ian Campbell --- docs/misc/arm/early-printk.txt | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'docs') diff --git a/docs/misc/arm/early-printk.txt b/docs/misc/arm/early-printk.txt index 10c30531f6..965add56b8 100644 --- a/docs/misc/arm/early-printk.txt +++ b/docs/misc/arm/early-printk.txt @@ -14,5 +14,9 @@ where mach is the name of the machine: The baud rate is hardcoded in xen/arch/arm/Rules.mk, see there when adding support for new machines. +If not explicitly requested with "EARLY_PRINTK_INIT_UART := y" in Rules.mk, +the code will not try to initialize the UART, so that bootloader or +firmware settings can be used for maximum compatibility. The baud rate +parameter is ignored in this case. By default early printk is disabled. -- cgit v1.2.3