I figured out another critical clock (patch 3), but didn't use the CLK_IS_CRITICAL flag since I want to just protect whatever clock happens to be the parent (there are #ifdefs in the firmware indicating that they've experimented with using different clocks as the parent).
I think these fixes are all suitable for 4.7. Eric Anholt (4): clk: bcm2835: Mark the VPU clock as critical clk: bcm2835: Mark GPIO clocks enabled at boot as critical clk: bcm2835: Mark the CM SDRAM clock's parent as critical clk: bcm2835: Skip PLLC clocks when deciding on a new clock parent drivers/clk/bcm/clk-bcm2835.c | 63 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 61 insertions(+), 2 deletions(-) -- 2.8.0.rc3