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William wu ebbdd2882e google/gru: Tuning USB 2.0 PHY0 and PHY1 squelch detection threshold
According to USB 2.0 Spec Table 7-7, the High-speed squelch
detection threshold Min 100mV and Max 150mV, and we set USB
2.0 PHY0 and PHY1 squelch detection threshold to 150mV by
default, so if the amplitude of differential voltage envelope
is < 150 mV, the USB 2.0 PHYs envelope detector will indicate
it as squelch.

On Kevin board, if we connect usb device with Samsung U2 cable,
we can see that the impedance of U2 cable is too big according
to the eye-diagram test report, and this cause serious signal
attenuation at the end of receiver, the amplitude of differential
voltage falls below 150mV.

This patch aims to reduce the PHY0 and PHY1 otg-ports squelch
detection threshold to 125mV (host-ports still use 150mV by
default), this is helpful to increase USB 2.0 PHY compatibility.

BRANCH=gru
BUG=chrome-os-partner:62320
TEST=Plug Samsung U2 cable + SEC P3 HDD 500GB/Galaxy S3 into
Type-C port, check if the USB device can be detected.

Change-Id: Ia0a2d354781c2ac757938409490f7c4eecdffe61
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 7d74311c25762668386061234df0562f84b7203e
Original-Change-Id: Ib20772f8fc2484d34c69f5938818aaa81ded7ed8
Original-Signed-off-by: William wu <wulf@rock-chips.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/431015
Original-Commit-Ready: Caesar Wang <wxt@rock-chips.com>
Original-Tested-by: Inno Park <ih.yoo.park@samsung.com>
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/18462
Reviewed-by: Martin Roth <martinroth@google.com>
Tested-by: build bot (Jenkins)
2017-02-23 18:51:21 +01:00
3rdparty 3rdparty: update arm-trusted-firmware submodule 2017-01-12 18:38:26 +01:00
configs configs/builder: Remove pre-defined VGA bios file 2017-01-20 17:37:19 +01:00
Documentation arch/x86/acpigen: Provide helper functions for enabling/disabling GPIO 2017-02-22 22:19:29 +01:00
payloads libpayload: Add oak config 2017-02-23 17:03:45 +01:00
src google/gru: Tuning USB 2.0 PHY0 and PHY1 squelch detection threshold 2017-02-23 18:51:21 +01:00
util board-status: Add README 2017-02-20 04:43:39 +01:00
.checkpatch.conf Update .checkpatch.conf 2016-09-02 18:22:04 +02:00
.clang-format
.gitignore .gitignore: Don’t track Tint directory 2017-01-22 21:15:58 +01:00
.gitmodules Set up 3rdparty/libgfxinit 2016-10-29 01:35:03 +02:00
.gitreview
COPYING
gnat.adc gnat.adc: Do not generate assertion code for Refined_Post 2016-10-29 01:33:31 +02:00
MAINTAINERS MAINTAINERS: Add lowrisc files to RISC-V 2016-11-12 19:30:26 +01:00
Makefile build system: mark sub-make invocations as parallelizable 2017-01-31 18:51:55 +01:00
Makefile.inc build system: mark sub-make invocations as parallelizable 2017-01-31 18:51:55 +01:00
README Remove extra newlines from the end of all coreboot files. 2016-07-31 18:19:33 +02:00
toolchain.inc Add minimal GNAT run time system (RTS) 2016-09-19 11:14:49 +02:00

-------------------------------------------------------------------------------
coreboot README
-------------------------------------------------------------------------------

coreboot is a Free Software project aimed at replacing the proprietary BIOS
(firmware) found in most computers.  coreboot performs a little bit of
hardware initialization and then executes additional boot logic, called a
payload.

With the separation of hardware initialization and later boot logic,
coreboot can scale from specialized applications that run directly
firmware, run operating systems in flash, load custom
bootloaders, or implement firmware standards, like PC BIOS services or
UEFI. This allows for systems to only include the features necessary
in the target application, reducing the amount of code and flash space
required.

coreboot was formerly known as LinuxBIOS.


Payloads
--------

After the basic initialization of the hardware has been performed, any
desired "payload" can be started by coreboot.

See http://www.coreboot.org/Payloads for a list of supported payloads.


Supported Hardware
------------------

coreboot supports a wide range of chipsets, devices, and mainboards.

For details please consult:

 * http://www.coreboot.org/Supported_Motherboards
 * http://www.coreboot.org/Supported_Chipsets_and_Devices


Build Requirements
------------------

 * make
 * gcc / g++
   Because Linux distribution compilers tend to use lots of patches. coreboot
   does lots of "unusual" things in its build system, some of which break due
   to those patches, sometimes by gcc aborting, sometimes - and that's worse -
   by generating broken object code.
   Two options: use our toolchain (eg. make crosstools-i386) or enable the
   ANY_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this
   case).
 * iasl (for targets with ACPI support)

Optional:

 * doxygen (for generating/viewing documentation)
 * gdb (for better debugging facilities on some targets)
 * ncurses (for 'make menuconfig' and 'make nconfig')
 * flex and bison (for regenerating parsers)


Building coreboot
-----------------

Please consult http://www.coreboot.org/Build_HOWTO for details.


Testing coreboot Without Modifying Your Hardware
------------------------------------------------

If you want to test coreboot without any risks before you really decide
to use it on your hardware, you can use the QEMU system emulator to run
coreboot virtually in QEMU.

Please see http://www.coreboot.org/QEMU for details.


Website and Mailing List
------------------------

Further details on the project, a FAQ, many HOWTOs, news, development
guidelines and more can be found on the coreboot website:

  http://www.coreboot.org

You can contact us directly on the coreboot mailing list:

  http://www.coreboot.org/Mailinglist


Copyright and License
---------------------

The copyright on coreboot is owned by quite a large number of individual
developers and companies. Please check the individual source files for details.

coreboot is licensed under the terms of the GNU General Public License (GPL).
Some files are licensed under the "GPL (version 2, or any later version)",
and some files are licensed under the "GPL, version 2". For some parts, which
were derived from other projects, other (GPL-compatible) licenses may apply.
Please check the individual source files for details.

This makes the resulting coreboot images licensed under the GPL, version 2.