serial/ns16550: add an option to avoid hanging on broken platforms

[karo-tx-uboot.git] / README

diff --git a/README b/README
index a80441c9b57f5ce26fe34484bffd7c5e206b81af..98dbe98c2ef5eee54256790eb24998a81ae720cb 100644 (file)
--- a/README
+++ b/README
@@ -616,6 +616,14 @@ The following options need to be configured:
                boot loader that has already initialized the UART.  Define this
                variable to flush the UART at init time.
 
                boot loader that has already initialized the UART.  Define this
                variable to flush the UART at init time.
 

+               CONFIG_SYS_NS16550_BROKEN_TEMT
+
+               16550 UART set the Transmitter Empty (TEMT) Bit when all output
+               has finished and the transmitter is totally empty. U-Boot waits
+               for this bit to be set to initialize the serial console. On some
+               broken platforms this bit is not set in SPL making U-Boot to
+               hang while waiting for TEMT. Define this option to avoid it.
+

 
 - Console Interface:
                Depending on board, define exactly one serial port
 
 - Console Interface:
                Depending on board, define exactly one serial port


@@ -815,6 +823,8 @@ The following options need to be configured:
                CONFIG_CMD_EDITENV        edit env variable
                CONFIG_CMD_EEPROM       * EEPROM read/write support
                CONFIG_CMD_ELF          * bootelf, bootvx
                CONFIG_CMD_EDITENV        edit env variable
                CONFIG_CMD_EEPROM       * EEPROM read/write support
                CONFIG_CMD_ELF          * bootelf, bootvx

+               CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
+               CONFIG_CMD_ENV_FLAGS    * display details about env flags

                CONFIG_CMD_EXPORTENV    * export the environment
                CONFIG_CMD_EXT2         * ext2 command support
                CONFIG_CMD_EXT4         * ext4 command support
                CONFIG_CMD_EXPORTENV    * export the environment
                CONFIG_CMD_EXT2         * ext2 command support
                CONFIG_CMD_EXT4         * ext4 command support


@@ -1484,6 +1494,21 @@ CBFS (Coreboot Filesystem) support
                Normally display is black on white background; define
                CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
 
                Normally display is black on white background; define
                CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
 

+               CONFIG_LCD_ALIGNMENT
+
+               Normally the LCD is page-aligned (tyically 4KB). If this is
+               defined then the LCD will be aligned to this value instead.
+               For ARM it is sometimes useful to use MMU_SECTION_SIZE
+               here, since it is cheaper to change data cache settings on
+               a per-section basis.
+
+               CONFIG_CONSOLE_SCROLL_LINES
+
+               When the console need to be scrolled, this is the number of
+               lines to scroll by. It defaults to 1. Increasing this makes
+               the console jump but can help speed up operation when scrolling
+               is slow.
+

                CONFIG_LCD_BMP_RLE8
 
                Support drawing of RLE8-compressed bitmaps on the LCD.
                CONFIG_LCD_BMP_RLE8
 
                Support drawing of RLE8-compressed bitmaps on the LCD.


@@ -1493,7 +1518,6 @@ CBFS (Coreboot Filesystem) support
                Enables an 'i2c edid' command which can read EDID
                information over I2C from an attached LCD display.
 
                Enables an 'i2c edid' command which can read EDID
                information over I2C from an attached LCD display.
 

-

 - Splash Screen Support: CONFIG_SPLASH_SCREEN
 
                If this option is set, the environment is checked for
 - Splash Screen Support: CONFIG_SPLASH_SCREEN
 
                If this option is set, the environment is checked for


@@ -2187,6 +2211,11 @@ CBFS (Coreboot Filesystem) support
                serial# is unaffected by this, i. e. it remains
                read-only.]
 
                serial# is unaffected by this, i. e. it remains
                read-only.]
 

+               The same can be accomplished in a more flexible way
+               for any variable by configuring the type of access
+               to allow for those variables in the ".flags" variable
+               or define CONFIG_ENV_FLAGS_LIST_STATIC.
+

 - Protected RAM:
                CONFIG_PRAM
 
 - Protected RAM:
                CONFIG_PRAM
 


@@ -2968,9 +2997,6 @@ Configuration Settings:
                non page size aligned address and this could cause major
                problems.
 
                non page size aligned address and this could cause major
                problems.
 

-- CONFIG_SYS_TFTP_LOADADDR:
-               Default load address for network file downloads
-

 - CONFIG_SYS_LOADS_BAUD_CHANGE:
                Enable temporary baudrate change while serial download
 
 - CONFIG_SYS_LOADS_BAUD_CHANGE:
                Enable temporary baudrate change while serial download
 


@@ -3112,6 +3138,49 @@ Configuration Settings:
        cases. This setting can be used to tune behaviour; see
        lib/hashtable.c for details.
 
        cases. This setting can be used to tune behaviour; see
        lib/hashtable.c for details.
 

+- CONFIG_ENV_FLAGS_LIST_DEFAULT
+- CONFIG_ENV_FLAGS_LIST_STATIC
+       Enable validation of the values given to enviroment variables when
+       calling env set.  Variables can be restricted to only decimal,
+       hexadecimal, or boolean.  If CONFIG_CMD_NET is also defined,
+       the variables can also be restricted to IP address or MAC address.
+
+       The format of the list is:
+               type_attribute = [s|d|x|b|i|m]
+               access_atribute = [a|r|o|c]
+               attributes = type_attribute[access_atribute]
+               entry = variable_name[:attributes]
+               list = entry[,list]
+
+       The type attributes are:
+               s - String (default)
+               d - Decimal
+               x - Hexadecimal
+               b - Boolean ([1yYtT|0nNfF])
+               i - IP address
+               m - MAC address
+
+       The access attributes are:
+               a - Any (default)
+               r - Read-only
+               o - Write-once
+               c - Change-default
+
+       - CONFIG_ENV_FLAGS_LIST_DEFAULT
+               Define this to a list (string) to define the ".flags"
+               envirnoment variable in the default or embedded environment.
+
+       - CONFIG_ENV_FLAGS_LIST_STATIC
+               Define this to a list (string) to define validation that
+               should be done if an entry is not found in the ".flags"
+               environment variable.  To override a setting in the static
+               list, simply add an entry for the same variable name to the
+               ".flags" variable.
+
+- CONFIG_ENV_ACCESS_IGNORE_FORCE
+       If defined, don't allow the -f switch to env set override variable
+       access flags.
+

 The following definitions that deal with the placement and management
 of environment data (variable area); in general, we support the
 following configurations:
 The following definitions that deal with the placement and management
 of environment data (variable area); in general, we support the
 following configurations:


@@ -4213,6 +4282,36 @@ Please note that changes to some configuration parameters may take
 only effect after the next boot (yes, that's just like Windoze :-).
 
 
 only effect after the next boot (yes, that's just like Windoze :-).
 
 

+Callback functions for environment variables:
+---------------------------------------------
+
+For some environment variables, the behavior of u-boot needs to change
+when their values are changed.  This functionailty allows functions to
+be associated with arbitrary variables.  On creation, overwrite, or
+deletion, the callback will provide the opportunity for some side
+effect to happen or for the change to be rejected.
+
+The callbacks are named and associated with a function using the
+U_BOOT_ENV_CALLBACK macro in your board or driver code.
+
+These callbacks are associated with variables in one of two ways.  The
+static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
+in the board configuration to a string that defines a list of
+associations.  The list must be in the following format:
+
+       entry = variable_name[:callback_name]
+       list = entry[,list]
+
+If the callback name is not specified, then the callback is deleted.
+Spaces are also allowed anywhere in the list.
+
+Callbacks can also be associated by defining the ".callbacks" variable
+with the same list format above.  Any association in ".callbacks" will
+override any association in the static list. You can define
+CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
+".callbacks" envirnoment variable in the default or embedded environment.
+
+

 Command Line Parsing:
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 Command Line Parsing:
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