Transition all boards that support arm cortex CPUs to armv7. This
leaves two armv6 kernels in the tree. RPI-B, which uses the BCM2835
which has a ARM1176 core, and VERSATILEPB, which is a qemu board setup
around the time RPI-B went in. Copy std.armv6 to std.armv7, even
though that duplicates a lot of stuff. More work needs to be done to
sort out the duplication.
Differential Revision: https://reviews.freebsd.org/D12027
All armv6 processors are plenty fast enough for HZ=1000.
No changes are made for older arm systems, because some chips are a bit
wimpy for 1000 while others do fine, so it has to be set on a per-config
basis.
BREAK_TO_DEBUGGER if they have a serial console (most do). A burst of
serial line noise (such as unplugging a usb serial adapter) can look like
a break and drop a working system into the debugger. The alt break sequence
(<CR>~^B) works fine on both serial and non-serial consoles.
each of the existing kernel configs. This gives a place to put config
that applies to the entire arch.
Add the ARM_NEW_PMAP option to std.armv6. This is working well in early
testing and it's time for wide exposure, but it's still nice to be able
to fall back to the old implementation for testing when a problem comes
along. Eventually the option and the old implementation will go away.
The opportunity now exists to move a whole lot of boilerplate from all the
arm kernel config files into std.arm*, but that's a commit for another day.
into the kernel, which is used mostly on early development stages.
On RPI(2) the DTB is loaded and modified by firmware and then handed to
kernel via U-Boot and ubldr.
The RPI firmware adds (or modify) a few valuable data to the in memory
DTB, like:
- System memory;
- Ethernet MAC address;
- framebuffer settings;
- Board serial and revision;
- clock-frequency for most of devices.
the Raspberry Pi B we support most of the devices are already supported,
however the base address has changed.
A few items are not working, or missing. The main ones are:
* DMA doesn't work in the sdhci driver.
* Enabling vchiq halts the boot, may be interrupt related.
* There is no U-Boot port yet so the DTB is embedded in the kernel.
The last point will make it difficult to boot FreeBSD, however there is
support for the Raspberry Pi 2 in the U-Boot git repo. As I have not tested
this it is left as an open task to create a port to build.
X-MFC: When the above issues are fixed
Sponsored by: ABT Systems Ltd
