README: Describe CONFIG_SYS_NO_FLASH

Unlike most configuration options defining this actually disables
support for a feature (parallel flash). Eventually the logic behind this
should probably be flipped so that '#ifndef CONFIG_SYS_NO_FLASH' becomes
'#ifdef CONFIG_HAS_PARALLEL_FLASH' but for now lets document the
existing behaviour.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>

diff --git a/README b/README
index 3b406c2820049ad9f2f64ca9e844b6aacd57b8be..c3fa549ea9c77a705f71321b5083423f8c9ff08d 100644 (file)
--- a/README
+++ b/README
@@ -3037,6 +3037,19 @@ CBFS (Coreboot Filesystem) support
                this is instead controlled by the value of
                /config/load-environment.
 
+- Parallel Flash support:
+               CONFIG_SYS_NO_FLASH
+
+               Traditionally U-boot was run on systems with parallel NOR
+               flash. This option is used to disable support for parallel NOR
+               flash. This option should be defined if the board does not have
+               parallel flash.
+
+               If this option is not defined one of the generic flash drivers
+               (e.g.  CONFIG_FLASH_CFI_DRIVER or CONFIG_ST_SMI) must be
+               selected or the board must provide an implementation of the
+               flash API (see include/flash.h).
+
 - DataFlash Support:
                CONFIG_HAS_DATAFLASH