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Simon Glass 74fedbe377 rockchip: spi: Add support for 16-bit APB reads
With a SPI clock above about 24MHz the APB cannot keep up when doing
individual byte transfers. Adjust the driver to use 16-bit reads when
it can, to remove this bottleneck.

Any transaction which involves writing bytes still uses 8-bit transfers,
to simplify the code. These are the transfers that are not time-critical
since they tend to be small. The case that really matters is reading from
SPI flash.

In general we can use 16-bit reads anytime we are transferring an even
number of bytes. If the code detects an odd number of bytes, it tries to
perform the operation in two steps: once in 16-bit mode with an even
number of bytes, and once in 8-bit mode for the final byte. This allow
us to use 16-bit reads even if asked to transfer (for example) 0xf423
bytes.

The limit on in_now and out_now is adjusted to 0xfffe to avoid an extra
transfer when transferring ~>=64KB.

CQ-DEPEND=CL:383232
BUG=chrome-os-partner:56556
BRANCH=none
TEST=boot on gru and see that things still work correctly. I tested (with
extra debugging) that the 16-bit case is being picked when it should be.

Change-Id: If5effae9a84e4de06537fd594bedf7f01d6a9c88
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: ec250b4931c7d99cc014e32ab597fca948299d08
Original-Change-Id: Idc5b7e5d82cdbdc1e8fe8b2d6da819edf2d5570c
Original-Signed-off-by: Simon Glass <sjg@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/381312
Original-Commit-Ready: Julius Werner <jwerner@chromium.org>
Original-Tested-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/16712
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>
2016-10-06 21:50:26 +02:00
3rdparty 3rdparty/blobs: Update to get AGESA binary for pcengines/apu2 2016-08-21 21:20:13 +02:00
Documentation Documentation/Intel/Soc: Update Quark FSP build instructions 2016-09-30 01:18:04 +02:00
payloads payloads/external/Memtest86Plus: Update stable to latest commit 2016-09-26 21:45:32 +02:00
src rockchip: spi: Add support for 16-bit APB reads 2016-10-06 21:50:26 +02:00
util util/release: Update genrelnotes.script to the latest version 2016-10-04 19:10:52 +02:00
.checkpatch.conf Update .checkpatch.conf 2016-09-02 18:22:04 +02:00
.clang-format
.gitignore .gitignore: Add coreinfo build residue, defconfig 2016-09-02 18:20:51 +02:00
.gitmodules git modules: rename git submodules to avoid hierarchies 2016-02-11 20:55:55 +01:00
.gitreview
COPYING
MAINTAINERS intel/amenia: Remove Amenia mainboard 2016-09-24 04:24:54 +02:00
Makefile Makefile: Give .ali files an empty recipe 2016-09-20 19:21:07 +02:00
Makefile.inc Build system: Remove IASL_WARNINGS_ARE_ERRORS option 2016-09-22 22:33:55 +02:00
README Remove extra newlines from the end of all coreboot files. 2016-07-31 18:19:33 +02:00
gnat.adc Make Ada a first class citizen 2016-09-19 11:14:18 +02:00
toolchain.inc Add minimal GNAT run time system (RTS) 2016-09-19 11:14:49 +02:00

README

-------------------------------------------------------------------------------
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.