MFC r303035 by markm:

Random bit generator (RBG) driver for RPi and RPi2.

Summary:
This driver supports the following methods to trigger gathering random bits from the hardware:
1. interrupt when the FIFO is full (default) fed into the harvest queue
2. callout (when BCM2835_RNG_USE_CALLOUT is defined) every second if hz is less than 100, otherwise hz / 100, feeding the random bits into the harvest queue

If the kernel is booted with verbose enabled, the contents of the registers will be dumped after the RBG is started during the attach routine.

Author: hackagadget_gmail.com (Stephen J. Kiernan)

Test Plan: Built RPI2 kernel and booted on board. Tested the different methods to feed the harvest queue (callout, interrupt) and the interrupt driven approach seems best. However, keeping the other method for people to be able to experiment with.

Reviewed By: adrian, delphij, markm

Differential Revision: https://reviews.freebsd.org/D6888

MFC r312914, r322694

r312914 by imp:
Honor LINKS=x y in dtb modules. We need this for compatibility links
for old, FreeBSD names.

r322694:
RPI DTS: Add value previously set by VideoCore and DTB links

Using latest U-Boot for RPI 1 or 2 the DTB loaded by the firmware is discarded.
The DTB was previously patched by the firmware to contain the DMA channel mask.
DTB provided by the rpi firmware or DTS in the Linux tree contain the raw value
directly. Do the same for our DTS as we cannot switch to the upstream ones yet.
Not having the DMA channel mask setup properly cause mmc not to be detected
(and probably other problems on driver using DMA).

Also, add links for rpi dtb to the name used by u-boot. This way the dtb can be
loaded by ubldr using the U-Boot env variable fdtfile.

Tested On: RPI B Rev2, RPI Zero, RPI 2 v1.1 RPI 2 v1.2

Thanks to Sylvain Garrigues <sylvain@sylvaingarrigues.com> for the help.

PR: 218344

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Rework BCM283x gpio interrupt controller for INTRNG. It's used on RPI-B
and RPI2 where INTRNG is already enabled by default.

Differential Revision: https://reviews.freebsd.org/D5810

Raspberry Pi firmware passes cache line size as a DTB parameter

- Add cache-line-size paramter to vchiq node
- Add cache_line_size DTB parameter referencing to
.../vchiq/cache-line-size property

Set the #address-cells and #size-cells properties on I2C controllers of
Raspberry-pi.

This fixes the issues of dtc(1) while compiling I2C addresses set in "reg"
property.

MFC after: 2 weeks

Integrate device-tree upstream files into the build process:
(1) Invoke cpp to bring in files via #include (although the old
/include/ stuff is supported still).
(2) bring in files from either vendor tree or freebsd-custom files
when building.
(3) move all dts* files from sys/boot/fdt/dts to
sys/boot/fdt/dts/${MACHINE} as appropriate.
(4) encode all the magic to do the build in sys/tools/fdt/make_dtb.sh
so that the different places in the tree use the exact same logic.
(5) switch back to gpl dtc by default. the bsdl one in the tree has
significant issues not easily addressed by those unfamiliar with
the code.

Add the Raspberry Pi SPI controller driver.

Reviewed by: rpaulo
Approved by: adrian (mentor)

Add the Raspberry Pi BSC (I2C compliant) controller driver.

Reviewed by: rpaulo
Approved by: adrian (mentor)

Split bcm2835-rpi-b.dts into bcm2835.dtsi and rpi.dts. This DTS actually works
on all R-Pi models because VideoCore binary patches it during boot.

Reviewed by: gonzo