u-boot/api
Jeroen Hofstee fbd239bea7 api/api_display: use the getters for console size info
cc: Che-Liang Chiou <clchiou@chromium.org>
Acked-by: Che-Liang Chiou <clchiou@chromium.org>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
2013-03-21 10:37:15 +01:00
..
api.c api: export LCD device to external apps 2011-11-15 23:58:27 +01:00
api_display.c api/api_display: use the getters for console size info 2013-03-21 10:37:15 +01:00
api_net.c net: drop !NET_MULTI code 2011-10-05 22:22:16 +02:00
api_platform-arm.c api: Fix broken build on ARM. 2009-07-23 00:10:53 +02:00
api_platform-powerpc.c Move arch/ppc to arch/powerpc 2010-04-21 23:42:38 +02:00
api_private.h api: export LCD device to external apps 2011-11-15 23:58:27 +01:00
api_storage.c api: remove un-needed ifdef CONFIG_API already handle by the Makefile 2009-05-15 22:13:01 +02:00
Makefile api: export LCD device to external apps 2011-11-15 23:58:27 +01:00
README Coding Style cleanup; update CHANGELOG 2008-01-10 00:55:14 +01:00

U-Boot machine/arch independent API for external apps
=====================================================

1.  Main assumptions

  - there is a single entry point (syscall) to the API

  - per current design the syscall is a C-callable function in the U-Boot
    text, which might evolve into a real syscall using machine exception trap
    once this initial version proves functional

  - the consumer app is responsible for producing appropriate context (call
    number and arguments)

  - upon entry, the syscall dispatches the call to other (existing) U-Boot
    functional areas like networking or storage operations

  - consumer application will recognize the API is available by searching
    a specified (assumed by convention) range of address space for the
    signature

  - the U-Boot integral part of the API is meant to be thin and non-intrusive,
    leaving as much processing as possible on the consumer application side,
    for example it doesn't keep states, but relies on hints from the app and
    so on

  - optional (CONFIG_API)


2. Calls

  - console related (getc, putc, tstc etc.)
  - system (reset, platform info)
  - time (delay, current)
  - env vars (enumerate all, get, set)
  - devices (enumerate all, open, close, read, write); currently two classes
    of devices are recognized and supported: network and storage (ide, scsi,
    usb etc.)


3. Structure overview

  - core API, integral part of U-Boot, mandatory
    - implements the single entry point (mimics UNIX syscall)

  - glue
    - entry point at the consumer side, allows to make syscall, mandatory
      part

    - helper conveniency wrappers so that consumer app does not have to use
      the syscall directly, but in a more friendly manner (a la libc calls),
      optional part

  - consumer application
    - calls directly, or leverages the provided glue mid-layer