u-boot

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History

Mike Frysinger e2a53458a7 net: drop !NET_MULTI code This is long over due. All but two net drivers have been converted, but those have now been dropped. The only thing left to do is actually delete all references to NET_MULTI and code that is compiled when that is not defined. So here we scrub the core code. Signed-off-by: Mike Frysinger <vapier@gentoo.org>		2011-10-05 22:22:16 +02:00
..
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 for external applications.	2008-01-09 19:39:36 +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
api.c	do_reset: unify duplicate prototypes	2010-11-28 21:47:24 +01:00
Makefile	Switch from archive libraries to partial linking	2010-11-17 21:02:18 +01:00
README	Coding Style cleanup; update CHANGELOG	2008-01-10 00:55:14 +01:00

README

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