libpayload: console: Allow output drivers to print whole strings at once

The console output driver framework in libpayload is currently built on
the putchar primitive, meaning that every driver's function gets called
one character at a time. This becomes an issue when we add drivers that
could output multiple characters at a time, but have a high constant
overhead per invocation (such as the planned GDB stub, which needs to
wrap a special frame around output strings and wait for an
acknowledgement from the server).

This patch adds a new 'write' function pointer to the
console_output_driver structure as an alternative to 'putchar'. Output
drivers need to provide at least one of the two ('write' is preferred if
available). The CBMEM console driver is ported as a proof of concept
(since it's our most performace-critical driver and should in theory
benefit the most from less function pointer invocations, although it's
probably still negligible compared to the big sprawling mess that is
printf()).

Even with this fix, the problem remains that printf() was written with
the putchar primitive in mind. Even though normal text already contains
an optimization to allow multiple characters at a time, almost all
formatting directives cause their output (including things like
padding whitespace) to be putchar()ed one character at a time.
Therefore, this patch reworks parts of the output code (especially
number printing) to all but remove that inefficiency (directives still
invoke an extra write() call, but at least not one per character). Since
I'm touching printf() core code anyway, I also tried to salvage what I
could from that weird, broken "return negative on error" code path (not
that any of our current output drivers can trigger it anyway).

A final consequence of this patch is that the responsibility to prepend
line feeds with carriage returns is moved into the output driver
implementations. Doing this only makes sense for drivers with explicit
cursor position control (i.e. serial or video), and things like the
CBMEM console that appears like a normal file to the system really have
no business containing carriage returns (we don't want people to
accidentally associate us with Windows, now, do we?).

BUG=chrome-os-partner:18390
TEST=Made sure video and CBMEM console still look good, tried printf()
with as many weird edge-case strings as I could find and compared serial
output as well as sprintf() return value.

Original-Change-Id: Ie05ae489332a0103461620f5348774b6d4afd91a
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/196384
Original-Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit ab1ef0c07736fe1aa3e0baaf02d258731e6856c0)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I78f5aedf6d0c3665924995cdab691ee0162de404
Reviewed-on: http://review.coreboot.org/7880
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
libpayload: usb: Try to avoid reusing device addresses

We recently changed the USB stack to detach devices aggressively that we
don't intend to use. This alone is not really a problem, but it
exarcerbates the fact that our device detachment itself is not very
good. We destroy any local info about the device, but we don't properly
disable the offending port. The device keeps thinking that it's active,
and if we later try to reuse that device address for another device
things become confused.

The real fix would be to properly disable all ports that we don't intend
to use. Unfortunately, this isn't really possible in our current
device/hub polymorphism structure, and I don't want to hack a new
disable_port() callback into usbdev_t that really doesn't belong there.
We will only be able to fix this cleanly after we ported all root hubs
to the generic_hub interface.

Until then, an easy workaround is to just avoid reusing addresses as
long as possible. This is firmware, so the chance that we'll ever run
through 127 devices is really small in practice. Even if we ever fix the
underlying issue, it's probably a smart precaution to keep.

BRANCH=nyan,rambi
BUG=chrome-os-partner:28328
TEST=Boot from a hub that has an "unknown" device in an earlier port
than the stick you want to boot from, make sure you can still boot.

Original-Change-Id: I9b522dd8cbcd441e8c3b8781fcecd2effa0f23ee
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/197420
Original-Reviewed-by: Shawn Nematbakhsh <shawnn@chromium.org>
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit 28b48aa69b55a983226edf2ea616f33cd4b959e2)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: Id4c5c92e75d6b5a7e8f0ee3e396c69c4efd13176
Reviewed-on: http://review.coreboot.org/7881
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>