1config DM_SERIAL 2 bool "Enable Driver Model for serial drivers" 3 depends on DM 4 help 5 Enable driver model for serial. This replaces 6 drivers/serial/serial.c with the serial uclass, which 7 implements serial_putc() etc. The uclass interface is 8 defined in include/serial.h. 9 10config DEBUG_UART 11 bool "Enable an early debug UART for debugging" 12 help 13 The debug UART is intended for use very early in U-Boot to debug 14 problems when an ICE or other debug mechanism is not available. 15 16 To use it you should: 17 - Make sure your UART supports this interface 18 - Enable CONFIG_DEBUG_UART 19 - Enable the CONFIG for your UART to tell it to provide this interface 20 (e.g. CONFIG_DEBUG_UART_NS16550) 21 - Define the required settings as needed (see below) 22 - Call debug_uart_init() before use 23 - Call debug_uart_putc() to output a character 24 25 Depending on your platform it may be possible to use this UART before 26 a stack is available. 27 28 If your UART does not support this interface you can probably add 29 support quite easily. Remember that you cannot use driver model and 30 it is preferred to use no stack. 31 32 You must not use this UART once driver model is working and the 33 serial drivers are up and running (done in serial_init()). Otherwise 34 the drivers may conflict and you will get strange output. 35 36choice 37 prompt "Select which UART will provide the debug UART" 38 depends on DEBUG_UART 39 40config DEBUG_UART_NS16550 41 bool "ns16550" 42 help 43 Select this to enable a debug UART using the ns16550 driver. You 44 will need to provide parameters to make this work. The driver will 45 be available until the real driver model serial is running. 46 47endchoice 48 49config DEBUG_UART_BASE 50 hex "Base address of UART" 51 depends on DEBUG_UART 52 help 53 This is the base address of your UART for memory-mapped UARTs. 54 55 A default should be provided by your board, but if not you will need 56 to use the correct value here. 57 58config DEBUG_UART_CLOCK 59 int "UART input clock" 60 depends on DEBUG_UART 61 help 62 The UART input clock determines the speed of the internal UART 63 circuitry. The baud rate is derived from this by dividing the input 64 clock down. 65 66 A default should be provided by your board, but if not you will need 67 to use the correct value here. 68 69config DEBUG_UART_SHIFT 70 int "UART register shift" 71 depends on DEBUG_UART 72 default 0 if DEBUG_UART 73 help 74 Some UARTs (notably ns16550) support different register layouts 75 where the registers are spaced either as bytes, words or some other 76 value. Use this value to specify the shift to use, where 0=byte 77 registers, 2=32-bit word registers, etc. 78 79config UNIPHIER_SERIAL 80 bool "Support for UniPhier on-chip UART" 81 depends on ARCH_UNIPHIER && DM_SERIAL 82 help 83 If you have a UniPhier based board and want to use the on-chip 84 serial ports, say Y to this option. If unsure, say N. 85