u-boot/arch/arm/Kconfig.debug
Masahiro Yamada 51b17d4946 arm: debug: add Kconfig entries for lowlevel debug
We have not had a good method to debug the early boot stage such as
lowlevel_init function.  I guess developers generally use dedicated
debuggers for that, but it is difficult in some cases.
(For example, my debugger cannot connect to the ARM processor when
it is in the secure state.  It sometimes happens when I need to
debug the early boot stage on ARM SoCs with secure extension.)

The low level debug feature in Linux would be also helpful for U-boot
when we are stucking in nasty problems where the console is not
available yet.

You have to enable CONFIG_DEBUG_LL to use this feature.
For now, only 8250-compatible UART devices are supported.
You can add a header file under arch/arm/include/debug/ directory
to support your UART device if necessary.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-10-26 22:23:12 +01:00

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menu "ARM debug"
config DEBUG_LL
bool "Low-level debugging functions"
depends on !ARM64
help
Say Y here to include definitions of printascii, printch, printhex
in U-Boot. This is helpful if you are debugging code that
executes before the console is initialized.
choice
prompt "Low-level debugging port"
depends on DEBUG_LL
config DEBUG_LL_UART_8250
bool "Low-level debugging via 8250 UART"
help
Say Y here if you wish the debug print routes to direct
their output to an 8250 UART. You can use this option
to provide the parameters for the 8250 UART rather than
selecting one of the platform specific options above if
you know the parameters for the port.
This option is preferred over the platform specific
options; the platform specific options are deprecated
and will be soon removed.
endchoice
config DEBUG_LL_INCLUDE
string
depends on DEBUG_LL
default "debug/8250.S" if DEBUG_LL_UART_8250 || DEBUG_UART_8250
default "mach/debug-macro.S"
# Compatibility options for 8250
config DEBUG_UART_8250
bool
config DEBUG_UART_PHYS
hex "Physical base address of debug UART"
depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250
# This is not used in U-Boot
config DEBUG_UART_VIRT
hex
default DEBUG_UART_PHYS
depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250
config DEBUG_UART_8250_SHIFT
int "Register offset shift for the 8250 debug UART"
depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250
default 2
config DEBUG_UART_8250_WORD
bool "Use 32-bit accesses for 8250 UART"
depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250
depends on DEBUG_UART_8250_SHIFT >= 2
config DEBUG_UART_8250_FLOW_CONTROL
bool "Enable flow control for 8250 UART"
depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250
endmenu