USB: ULPI: clean a mixup of return types

[oweals/u-boot.git] / README

diff --git a/README b/README
index e9d189108f70f2cf526395fd2db06e10e7ec10ab..ff72e4705f5d7142322e51d808f07c491edef7c0 100644 (file)
--- a/README
+++ b/README
@@ -638,6 +638,23 @@ The following options need to be configured:
                'Sane' compilers will generate smaller code if
                CONFIG_PRE_CON_BUF_SZ is a power of 2
 
+- Pre-console putc():
+               Prior to the console being initialised, console output is
+               normally silently discarded. This can be annoying if a
+               panic() happens in this time.
+
+               If the CONFIG_PRE_CONSOLE_PUTC option is defined, then
+               U-Boot will call board_pre_console_putc() for each output
+               character in this case, This function should try to output
+               the character if possible, perhaps on all available UARTs
+               (it will need to do this directly, since the console code
+               is not functional yet). Note that if the panic happens
+               early enough, then it is possible that board_init_f()
+               (or even arch_cpu_init() on ARM) has not been called yet.
+               You should init all clocks, GPIOs, etc. that are needed
+               to get the character out. Baud rates will need to default
+               to something sensible.
+
 - Boot Delay:  CONFIG_BOOTDELAY - in seconds
                Delay before automatically booting the default image;
                set to -1 to disable autoboot.