At the current stage, the USB HID and storage drivers are prinicpally
working but not stable. If interrupts are not processed fast enough,
devices will get sporadically disconnected.
The USB host-controller driver is not part of the normal Linux kernel.
For this reason, we need to download it separately. There exists a
'prepare_rpi' rule in the 'dde_linux/Makefile' to automate this process.
This patch principally allows to install symlinks to out-of-Linux tree
drivers into the contrib directory. Those files are then considered for
the 'lx_emul.h' symlink procedure. Is useful as a temporary mechanism
while developing the rpi USB driver.
Originally, the convenience utility for accessing a process
configuration came in the form of a header file. But this causes
aliasing problems if multiple compilation units access the config while
the configuration gets dynamically updated. Moving the implementation of
the accessor to the singleton object into a library solves those
problems.
This fixes issues with several HID keyboards by implementing
get_unaligned_le16(), which obviously may also fix other not-yet-known
issues. Hint: I had to look out for suspicious lines like follows in the
verbose log.
[init -> usb_drv] get_unaligned_le16 called, not implemented
Also, quirks for cherry keyboards are now applied.
In usb.inc all required Linux include files of the Linux code are looked up
by 'sed'ing through the files of SRC_C and SRC_CC. The Linux include files
are then added as dependency to the SRC_C and SRC_CC files and during dependency
resolution symbolic links to the lx_emul.h will be created.
In the platform specific usb.mk file there are the Linux driver files
added, but unfortunately after including usb.inc. So, for them no dependency
to any Linux include header file is generated and so no symbolic files are
generated.
If the driver code file is compiled as first, as for asix.c, the symbolic links
of the include files are missing and compilation fails.
Add the Linux driver code files to SRC_C before including usb.inc in the
platform specific usb.mk files.
