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Some SOCs (like pistachio, for instance) provide an 8250 compatible
UART, which has the same register layout, but mapped to a bus of a
different width.
Instead of adding a new driver for these controllers, it is better to
have coreboot report UART register width to libpayload, and have it
adjust the offsets accordingly when accessing the UART.
BRANCH=none
BUG=chrome-os-partner:31438
TEST=with the rest of the patches integrated depthcharge console messages
show up when running on the FPGA board
Change-Id: I05891a9471a5369d3bfafe90cd0c9b0a7e5a667e
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 2c30845f269ec6ae1d53ddc5cda0b4320008fa42
Original-Change-Id: Ia0a37cd5f24a1ee4d0334f8a7e3da5df0069cec4
Original-Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/240027
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9739
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
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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>
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