On 04/24/2015 12:41 PM, Eric Anholt wrote:
Stephen Warren <swarren@xxxxxxxxxxxxx> writes:
On 04/21/2015 12:09 PM, Eric Anholt wrote:
This is my first submission of a Raspberry Pi 2 port. It can be found
at https://github.com/anholt/linux/tree/bcm2836
I'm using the 2835 interrupt controller support, without adding the
checks for ARM local interrupts first. That means no support for IPIs
(and thus no SMP), no PMU events, and no local timer (I'm using the
same 2835 peripheral one).
It supports a similar featureset to Pi 1 at this point. Serial and SD
cards work. Just one CPU supported. USB (ethernet) works if you use
U-Boot, or my mailbox series
(https://github.com/anholt/linux/tree/bcm2836-mbox).
I can't quite get this to work. I think what's happening is that U-Boot
is over-writing the location of the code/data that the CPU1..3 pin loop
uses. Do you know what that address is so I can confirm that?
I suspect this because when I load the kernel/DT in U-Boot, or when I
jump to the kernel to boot it, I see lots of extra duplicated characters
on the UART, like all 4 CPUs are booting Linux. For example:
Oops, I was just extrapolating that U-Boot would work. I've quit using
it because of the extra configuration work (particularly the compiled
text files for the boot scripts).
You don't need any compiled text files if you create an extlinux.conf
rather than a boot.scr. extlinux.conf is plain text.
To boot without U-Boot: Could you say what's in your config.txt? I
assume I can just copy the kernel zImage as kernel.img, and the DTB from
the kernel build tree without renaming it?
I haven't looked into how SMP works, because I don't have the interrupt
support necessary yet (bcm2836-irq branch for hacks in that direction).
And in further testing, the USB is actually not working and I'm not sure
what gave me the idea that it was.
It might be intermittent depending on (GPU) cache content. We need to
fix the kernel in a similar fashion to the following U-Boot commits:
http://git.denx.de/?p=u-boot.git;a=commit;h=79340db7f1f676b8eb5911f4993ebedf27009c0b
ARM: bcm2835: implement phys_to_bus/bus_to_phys
http://git.denx.de/?p=u-boot.git;a=commit;h=5c0beb5c58c86d2a6d12dee6330dc85554de5c60
usb: dwc2: use phys_to_bus/bus_to_phys
http://git.denx.de/?p=u-boot.git;a=commit;h=122426d46e31391480c4b83b1003e4feca24d491
ARM: bcm2835: use phys_to_bus() for mbox
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
