Hi Tom,
On 06/05/16 16:11, Tom Rini wrote:
On Wed, May 04, 2016 at 11:14:39PM +0100, André Przywara wrote:
On 04/05/16 22:46, Peter Robinson wrote:
On Wed, May 4, 2016 at 10:15 PM, Andre Przywara andre.przywara@arm.com wrote:
Rename the defconfig file for the Pine64 from pine64_plus_defconfig to pine64_defconfig. The differences between the two versions (more RAM and a different Ethernet PHY) don't justify two board versions, so lets stick with the generic name and try to differentiate between the versions at runtime if this is needed later.
Signed-off-by: Andre Przywara andre.przywara@arm.com
configs/pine64_defconfig | 20 ++++++++++++++++++++ configs/pine64_plus_defconfig | 20 -------------------- 2 files changed, 20 insertions(+), 20 deletions(-) create mode 100644 configs/pine64_defconfig delete mode 100644 configs/pine64_plus_defconfig
diff --git a/configs/pine64_defconfig b/configs/pine64_defconfig new file mode 100644 index 0000000..0977334 --- /dev/null +++ b/configs/pine64_defconfig @@ -0,0 +1,20 @@ +CONFIG_ARM=y +CONFIG_ARCH_SUNXI=y +CONFIG_MACH_SUN50I=y +CONFIG_DRAM_CLK=672 +CONFIG_DRAM_ZQ=3881915 +# CONFIG_VIDEO is not set +CONFIG_DEFAULT_DEVICE_TREE="sun50i-a64-pine64-plus"
If you're building a single u-boot for all variants of Pine64,
Yes!
something which I'd prefer, I don't think we can just set a default but rather need some logic to specify the DT name based on which board is booting. This is done for example in the BeagleBone config to detect the various variants of the BeagleBones.
OK, I will look at this.
I wonder if we can just use the plus .dts and then remove the parts that the non-plus is missing and push that through to the kernel. U-Boot already takes care of one difference: the DRAM size. I think we could also detect the different Ethernet PHY (or deduce this from the DRAM size?) and fix that up. For the third difference - camera and LCD connectors - U-Boot itself doesn't even care. But it would be nice if having a 512 MB board would result in the respective DT nodes to be deleted. This way we would have _one_ DT source - the U-Boot repository - and automatically deliver a fixed up version to every OS.
What do you think?
How well can you at run time determine which variant of pine we're on?
So for the Pine64 there are three models at the moment, each with a different size of DRAM. U-Boot detects this already, so for the time being we could just tell them apart easily - be it at SPL or U-Boot level. There is a good chance that community feedback will be heard on future boards (at least from Pine64.com), so we can make sure that even new boards are somehow distinguishable.
What's coming after v2016.05 is a whole bunch of examples of supporting N similar but different boards that we can runtime detect and picking the appropriate DT to use. That however is at the SPL level. We need to I suppose think about how to do something similar at the U-Boot level itself.
Is the following a feasible approach? - use the plus model DT as a base - detect RAM size - if RAM == 512MB change Ethernet PHY property from RGMII to MII nuke (potential) CSI, camera, touchscreen nodes - push this DT by default to any kernel loaded - be done.
Sounds like easily coded, if one allows either board specific hooks or a generic framework for such rules.
Does that make sense?
Cheers, Andre.
In terms of trying to "fixup" things, if you don't want to handle them at the kernel level as overlays, there's examples today of using 'fdt ...' to whack nodes as needed I'm fairly certain. It does depend on being able to tell at runtime what you're on of course.