rk3399 platform have dfi controller can monitor ddr load, and dcf controller to handle ddr register so we can get the right ddr frequency and make ddr controller happy work(which will implement in bl31). So we do ddr frequency scaling with following flow:
kernel bl31
monitor ddr load | | get_target_rate | | pass rate to bl31 clk_set_rate(ddr) --------------------->run dcf flow | | | | wait dcf interrupt<-------------------trigger dcf interrupt | | return
Lin Huang (5): Documentation: bindings: add dt documentation for dfi controller PM / devfreq: event: support rockchip dfi controller Documentation: bindings: add dt documentation for rk3399 dmc PM / devfreq: rockchip: add devfreq driver for rk3399 dmc drm/rockchip: Add dmc notifier in vop driver
Following patch: clk: rockchip: add new clock-type for the ddrclk clk: rockchip: rk3399: add SCLK_DDRCLK ID for ddrc clk: rockchip: rk3399: add ddrc clock support have applied to: http://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip.git/v4.9...
.../bindings/devfreq/event/rockchip-dfi.txt | 19 + .../devicetree/bindings/devfreq/rk3399_dmc.txt | 173 ++++++++ drivers/devfreq/Kconfig | 11 + drivers/devfreq/Makefile | 1 + drivers/devfreq/event/Kconfig | 7 + drivers/devfreq/event/Makefile | 1 + drivers/devfreq/event/rockchip-dfi.c | 256 +++++++++++ drivers/devfreq/rk3399_dmc.c | 480 +++++++++++++++++++++ drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 116 +++++ 9 files changed, 1064 insertions(+) create mode 100644 Documentation/devicetree/bindings/devfreq/event/rockchip-dfi.txt create mode 100644 Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt create mode 100644 drivers/devfreq/event/rockchip-dfi.c create mode 100644 drivers/devfreq/rk3399_dmc.c