summaryrefslogtreecommitdiff
path: root/README
diff options
context:
space:
mode:
authorGraeme Russ <graeme.russ@gmail.com>2011-09-01 00:48:27 +0000
committerWolfgang Denk <wd@denx.de>2011-10-05 22:03:09 +0200
commit9558b48af006a34d3ab7f0bd13a76b97acd45e47 (patch)
treed2fbeae7e5f2ef15cc7194fd21d504229259f2de /README
parentcc9abfe4ceb360e9adedc4ed44eae0fcc3fd184c (diff)
downloadu-boot-imx-9558b48af006a34d3ab7f0bd13a76b97acd45e47.zip
u-boot-imx-9558b48af006a34d3ab7f0bd13a76b97acd45e47.tar.gz
u-boot-imx-9558b48af006a34d3ab7f0bd13a76b97acd45e47.tar.bz2
console: Implement pre-console buffer
Allow redirection of console output prior to console initialisation to a temporary buffer. To enable this functionality, the board (or arch) must define: - CONFIG_PRE_CONSOLE_BUFFER - Enable pre-console buffer - CONFIG_PRE_CON_BUF_ADDR - Base address of pre-console buffer - CONFIG_PRE_CON_BUF_SZ - Size of pre-console buffer (in bytes) The pre-console buffer will buffer the last CONFIG_PRE_CON_BUF_SZ bytes Any earlier characters are silently dropped.
Diffstat (limited to 'README')
-rw-r--r--README14
1 files changed, 14 insertions, 0 deletions
diff --git a/README b/README
index 91b6695..dfc7ada 100644
--- a/README
+++ b/README
@@ -619,6 +619,20 @@ The following options need to be configured:
must be defined, to setup the maximum idle timeout for
the SMC.
+- Pre-Console Buffer:
+ Prior to the console being initialised (i.e. serial UART
+ initialised etc) all console output is silently discarded.
+ Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
+ buffer any console messages prior to the console being
+ initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
+ bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
+ a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
+ bytes are output before the console is initialised, the
+ earlier bytes are discarded.
+
+ 'Sane' compilers will generate smaller code if
+ CONFIG_PRE_CON_BUF_SZ is a power of 2
+
- Boot Delay: CONFIG_BOOTDELAY - in seconds
Delay before automatically booting the default image;
set to -1 to disable autoboot.