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ce30e3ff1e
This is defined based on two other CONFIGs for all boards except sandbox and durian. For sandbox the value does not matter. For durian the value seems excessive. Drop the option completely, to simplify configuration and reduce the number of things we need to convert to Kconfig. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Stefan Roese <sr@denx.de> |
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| .. | ||
| api_display.c | ||
| api_net.c | ||
| api_platform-arm.c | ||
| api_platform-mips.c | ||
| api_platform-powerpc.c | ||
| api_private.h | ||
| api_storage.c | ||
| api.c | ||
| Kconfig | ||
| Makefile | ||
| 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