Xen on ARM Early Printk
Contents
Introduction
Early printk can only be enabled if CONFIG_DEBUG=y or in EXPERT mode. You may want to enable it if you are debugging 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.
How to enable early printk
Select one of the Early printk via UART in the choice possible for Early printk in the Debugging options of Kconfig. You will then need to set other options, which depends on the driver selected.
For more information refer: xen.git:docs/misc/arm/early-printk.txt
Platform predefined configurations
When in doubt, you can refer to the following list of predefined platform configurations for the early printk.
CONFIG_EARLY_UART_BASE_ADDRESS
Platform | Address |
---|---|
Early printk with 8250 on Broadcom 7445D0 boards with A15 processors | 0xf040ab00 |
Early printk with 8250 on DRA7 platform | 0x4806a000 |
Early printk with the second UART on Exynos5250 | 0x12c20000 |
Early printk with pl011 on ARM Fastmodel software emulators | 0x1c090000 |
Early printk with pl011 with Hikey 960 | 0xfff32000 |
Early printk with pl011 on Juno platform | 0x7ff80000 |
Early printk with SCIF0 on Renesas Lager board (R-Car H2 processor) | 0xe6e60000 |
Early printk with pl011 on Calxeda Midway processors | 0xfff36000 |
Early printk with MVEBU for Marvell Armada 3700 SoCs | 0xd0012000 |
Early printk with UART3 on TI OMAP5432 processors | 0x48020000 |
Early printk with SCIF2 on Renesas R-Car Gen3 processors | 0xe6e88000 |
Early printk with pl011 for AMD Seattle processor | 0xe1010000 |
Early printk with 8250 on Allwinner A31 processors | 0x01c28000 |
Early printk with 8250 on Allwinner A20 processors | 0x01c28000 |
Early printk with pl011 for Cavium ThunderX processor | 0x87e024000000 |
Early printk with pl011 for versatile express | 0x1c090000 |
Early printk with 820 on Xgene mcdivitt platform | 0x1c021000 |
Early printk with 820 on Xgene storm platform | 0x1c020000 |
Early printk with Cadence UART for Xilinx ZynqMP SoCs | 0xff000000 |
EARLY_UART_PL011_BAUD_RATE
Platform | Baud rate |
---|---|
Early printk with pl011 on ARM Fastmodel software emulators | 115200 |
EARLY_UART_8250_REG_SHIFT
Platform | Shift |
---|---|
Early printk with 8250 on Broadcom 7445D0 boards with A15 processors | 2 |
Early printk with 8250 on DRA7 platform | 2 |
Early printk with UART3 on TI OMAP5432 processors | 2 |
Early printk with 8250 on Allwinner A31 processors | 2 |
Early printk with 8250 on Allwinner A20 processors | 2 |
Early printk with 820 on Xgene mcdivitt platform | 2 |
Early printk with 820 on Xgene storm platform | 2 |