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config DM_SERIAL
bool "Enable Driver Model for serial drivers"
depends on DM
help
Enable driver model for serial. This replaces
drivers/serial/serial.c with the serial uclass, which
implements serial_putc() etc. The uclass interface is
defined in include/serial.h.
config DEBUG_UART
bool "Enable an early debug UART for debugging"
help
The debug UART is intended for use very early in U-Boot to debug
problems when an ICE or other debug mechanism is not available.
To use it you should:
- Make sure your UART supports this interface
- Enable CONFIG_DEBUG_UART
- Enable the CONFIG for your UART to tell it to provide this interface
(e.g. CONFIG_DEBUG_UART_NS16550)
- Define the required settings as needed (see below)
- Call debug_uart_init() before use
- Call debug_uart_putc() to output a character
Depending on your platform it may be possible to use this UART before
a stack is available.
If your UART does not support this interface you can probably add
support quite easily. Remember that you cannot use driver model and
it is preferred to use no stack.
You must not use this UART once driver model is working and the
serial drivers are up and running (done in serial_init()). Otherwise
the drivers may conflict and you will get strange output.
choice
prompt "Select which UART will provide the debug UART"
depends on DEBUG_UART
config DEBUG_UART_NS16550
bool "ns16550"
help
Select this to enable a debug UART using the ns16550 driver. You
will need to provide parameters to make this work. The driver will
be available until the real driver model serial is running.
config DEBUG_EFI_CONSOLE
bool "EFI"
depends on EFI_APP
help
Select this to enable a debug console which calls back to EFI to
output to the console. This can be useful for early debugging of
U-Boot when running on top of EFI (Extensive Firmware Interface).
This is a type of BIOS used by PCs.
endchoice
config DEBUG_UART_BASE
hex "Base address of UART"
depends on DEBUG_UART
help
This is the base address of your UART for memory-mapped UARTs.
A default should be provided by your board, but if not you will need
to use the correct value here.
config DEBUG_UART_CLOCK
int "UART input clock"
depends on DEBUG_UART
help
The UART input clock determines the speed of the internal UART
circuitry. The baud rate is derived from this by dividing the input
clock down.
A default should be provided by your board, but if not you will need
to use the correct value here.
config DEBUG_UART_SHIFT
int "UART register shift"
depends on DEBUG_UART
default 0 if DEBUG_UART
help
Some UARTs (notably ns16550) support different register layouts
where the registers are spaced either as bytes, words or some other
value. Use this value to specify the shift to use, where 0=byte
registers, 2=32-bit word registers, etc.
config SANDBOX_SERIAL
bool "Sandbox UART support"
depends on SANDBOX && DM
help
Select this to enable a seral UART for sandbox. This is required to
operate correctly, otherwise you will see no serial output from
sandbox. The emulated UART will display to the console and console
input will be fed into the UART. This allows you to interact with
U-Boot.
The operation of the console is controlled by the -t command-line
flag. In raw mode, U-Boot sees all characters from the terminal
before they are processed, including Ctrl-C. In cooked mode, Ctrl-C
is processed by the terminal, and terminates U-Boot. Valid options
are:
-t raw-with-sigs Raw mode, Ctrl-C will terminate U-Boot
-t raw Raw mode, Ctrl-C is processed by U-Boot
-t cooked Cooked mode, Ctrl-C terminates
config UNIPHIER_SERIAL
bool "Support for UniPhier on-chip UART"
depends on ARCH_UNIPHIER && DM_SERIAL
help
If you have a UniPhier based board and want to use the on-chip
serial ports, say Y to this option. If unsure, say N.
config X86_SERIAL
bool "Support for 16550 serial port on x86 machines"
depends on X86
default y
help
Most x86 machines have a ns16550 UART or compatible. This can be
enabled in the device tree with the correct input clock frequency
provided (default 1843200). Enable this to obtain serial console
output.
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