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Implement SDRAM init using the Memory Reference Code (mrc.bin) provided in
the board directory and the SDRAM SPD information in the device tree. This
also needs the Intel Management Engine (me.bin) to work. Binary blobs
everywhere: so far we have MRC, ME and microcode.
SDRAM init works by setting up various parameters and calling the MRC. This
in turn does some sort of magic to work out how much memory there is and
the timing parameters to use. It also sets up the DRAM controllers. When
the MRC returns, we use the information it provides to map out the
available memory in U-Boot.
U-Boot normally moves itself to the top of RAM. On x86 the RAM is not
generally contiguous, and anyway some RAM may be above 4GB which doesn't
work in 32-bit mode. So we relocate to the top of the largest block of
RAM we can find below 4GB. Memory above 4GB is accessible with special
functions (see physmem).
It would be possible to build U-Boot in 64-bit mode but this wouldn't
necessarily provide any more memory, since the largest block is often below
4GB. Anyway U-Boot doesn't need huge amounts of memory - even a very large
ramdisk seldom exceeds 100-200MB. U-Boot has support for booting 64-bit
kernels directly so this does not pose a limitation in that area. Also there
are probably parts of U-Boot that will not work correctly in 64-bit mode.
The MRC is one.
There is some work remaining in this area. Since memory init is very slow
(over 500ms) it is possible to save the parameters in SPI flash to speed it
up next time. Suspend/resume support is not fully implemented, or at least
it is not efficient.
With this patch, link boots to a prompt.
Signed-off-by: Simon Glass <sjg@chromium.org>
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Enable GPIO support and provide the required GPIO setup information to
the driver.
Signed-off-by: Simon Glass <sjg@chromium.org>
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Add two microcode updates that are provided for this CPU. The updates
have been converted to a device tree form.
Note: SPDX submission has been done. If this license is approved I will
convert the files to use SPDX.
Signed-off-by: Simon Glass <sjg@chromium.org>
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The PCH (Platform Controller Hub) includes an LPC (Low Pin Count) device
which provides a serial port. This is accessible on Chromebooks, so enable
it early in the boot process.
Signed-off-by: Simon Glass <sjg@chromium.org>
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Add more information so that U-Boot can find the address of the serial port.
Also fix the reg-shift value.
Signed-off-by: Simon Glass <sjg@chromium.org>
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Add the required node describing how to find the EC on link.
Signed-off-by: Simon Glass <sjg@chromium.org>
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Unlike Linux Kernel, U-Boot historically had *.dts files under
board/$(VENDOR)/dts/ and *.dtsi files under arch/$(ARCH)/dts/.
I think arch/$(ARCH)/dts dicretory is a better location
to store both *.dts and *.dtsi files.
For example, before this commit, board/xilinx/dts directory
had both Microblaze dts (microblaze-generic.dts) and
ARM dts (zynq-*.dts), which are totally unrelated.
This commit moves *.dts to arch/$(ARCH)/dts/ directories,
allowing us to describe nicely mutiple DTBs generation in the next commit.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
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