fb7d38a70e
On Meson8b the only valid input clock is MPLL2. The bootloader
configures that to run at 500002394Hz which cannot be divided evenly
down to 125MHz using the m250_div clock. Currently the common clock
framework chooses a m250_div of 2 - with the internal fixed
"divide by 10" this results in a RGMII TX clock of 125001197Hz (120Hz
above the requested 125MHz).
Letting the common clock framework propagate the rate changes up to the
parent of m250_mux allows us to get the best possible clock rate. With
this patch the common clock framework calculates a rate of
very-close-to-250MHz (249999701Hz to be exact) for the MPLL2 clock
(which is the mux input). Dividing that by 2 (which is an internal,
fixed divider for the RGMII TX clock) gives us an RGMII TX clock of
124999850Hz (which is only 150Hz off the requested 125MHz, compared to
1197Hz based on the MPLL2 rate set by u-boot and the Amlogic GPL kernel
sources).
SoCs from the Meson GX series are not affected by this change because
the input clock is FCLK_DIV2 whose rate cannot be changed (which is fine
since it's running at 1GHz, so it's already a multiple of 250MHz and
125MHz).
Fixes:
|
||
|---|---|---|
| Documentation | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.