mirror of
https://github.com/xen-project/xen.git
synced 2026-10-29 18:50:05 +01:00
Zoltan Kiss
4a7abc58ff
This platform is no longer actively used, but it makes GICv2 development harder. Signed-off-by: Zoltan Kiss <zoltan.kiss@linaro.org> Acked-by: Ian Campbell <ian.campbell@citrix.com>
57 lines
2.4 KiB
Plaintext
57 lines
2.4 KiB
Plaintext
How to enable early printk
|
|
|
|
Early printk can only be enabled if debug=y. You may want to enable it if
|
|
you are debbuging code that executes before the console is initialized.
|
|
|
|
Note that selecting this option will limit Xen to a single UART definition.
|
|
Attempting to boot Xen image on a different platform *will not work*, so this
|
|
option should not be enable for Xens that are intended to be portable.
|
|
|
|
CONFIG_EARLY_PRINTK=<INC>,<BASE_ADDRESS>,<OTHER_OPTIONS>
|
|
|
|
<INC> and <BASE_ADDRESS> are mandatory arguments:
|
|
|
|
- <INC> is the name of the driver, see xen/arch/arm/arm{32,64}/debug-*.inc
|
|
(where <INC> corresponds to the wildcarded *).
|
|
- <BASE_ADDRESS> is the base physical address of the UART to use
|
|
|
|
<OTHER_OPTIONS> varies depending on <INC>:
|
|
|
|
- 8250,<BASE_ADDRESS>,<REG_SHIFT>
|
|
- <REG_SHIFT> is, optionally, the left-shift to apply to the
|
|
register offsets within the uart.
|
|
- pl011,<BASE_ADDRESS>,<BAUD_RATE>
|
|
- <BAUD_RATE> is, optionally a baud rate which should be used to
|
|
configure the UART at start of day.
|
|
|
|
If <BAUD_RATE> is not given then the code will not try to
|
|
initialize the UART, so that bootloader or firmware settings can
|
|
be used for maximum compatibility.
|
|
- For all other uarts there are no additional options.
|
|
|
|
As a convenience it is also possible to select from a list of
|
|
predefined configurations using CONFIG_EARLY_PRINTK=mach where mach is
|
|
the name of the machine:
|
|
|
|
- brcm: printk with 8250 on Broadcom 7445D0 boards with A15 processors.
|
|
- dra7: printk with 8250 on DRA7 platform
|
|
- exynos5250: printk with the second UART
|
|
- fastmodel: printk on ARM Fastmodel software emulators
|
|
- juno: printk with pl011 on Juno platform
|
|
- lager: printk with SCIF0 on Renesas R-Car H2 processors
|
|
- midway: printk with the pl011 on Calxeda Midway processors
|
|
- omap5432: printk with UART3 on TI OMAP5432 processors
|
|
- seattle: printk with pl011 for AMD Seattle processor
|
|
- sun6i: printk with 8250 on Allwinner A31 processors
|
|
- sun7i: printk with 8250 on Allwinner A20 processors
|
|
- thunderx: printk with pl011 for Cavium ThunderX processor
|
|
- vexpress: printk with pl011 for versatile express
|
|
- xgene-mcdivitt: printk with 820 on Xgene mcdivitt platform
|
|
- xgene-storm: printk with 820 on Xgene storm platform
|
|
- zynqmp: printk with Cadence UART for Xilinx ZynqMP SoCs
|
|
|
|
These settings are is hardcoded in xen/arch/arm/Rules.mk,
|
|
see there when adding support for new machines.
|
|
|
|
By default early printk is disabled.
|