On Sun, Aug 2, 2015 at 6:13 PM, Leo Yan [off-list ref] wrote:

On Hi6220, there have some clocks which can use mailbox channel to send
messages to power controller to change frequency; this includes CPU, GPU
and DDR clocks.

For dynamic frequency scaling, firstly need write the frequency value to
SRAM region, and then send message to mailbox to trigger power controller
to handle this requirement. This driver will use syscon APIs to pass SRAM
memory region and use common mailbox APIs for channels accessing.

This init driver will support cpu frequency change firstly.

Signed-off-by: Leo Yan <redacted>

The kernelci.org build/boot bot detected boot failures in
linux-next[1], and the failure was bisected down to this patch (landed
in linux-next as commit c1628a2c416da947f5afac615d53189250fa49cb.

I verifed that reverting this commit on top of next-20150901 gets the
hikey booting again.

Kevin

[1] http://kernelci.org/boot/hi6220-hikey/