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authorDouglas Anderson <dianders@chromium.org>2016-08-18 21:56:01 +0300
committerHeiko Stuebner <heiko@sntech.de>2016-10-16 03:42:29 +0300
commit3f2fe461c7548153dec239f44ff2aebafc8e7fdf (patch)
tree324142b242a53ba4b497557c47daae2f5bb5e2c5 /Documentation/early-userspace
parent1001354ca34179f3db924eb66672442a173147dc (diff)
downloadlinux-3f2fe461c7548153dec239f44ff2aebafc8e7fdf.tar.xz
soc: rockchip: power-domain: Don't (incorrectly) set rk3399 up/down counts
On rk3288 it was important that powerdown and powerup counts for the CPU/GPU in the kernel because: * The power on default was crazy long. * We couldn't rely on the firmware to set this up because really this wasn't the firmware's job--the kernel was the only one that really cared about bringing up / down CPUs and the GPU and doing suspend / resume (which involves bringing up / down CPUs). On newer ARM systems (like rk3399) ARM Trusted Firmware is in charge of bringing up and down the CPUs and it really should be in charge of setting all these counts right. After all ATF is in charge of suspend / resume and CPU up / down. Let's get out of the way and let ATF do its job. A few other motivations for doing this: * Depending on another configuration (PMU_24M_EN_CFG) these counts can be either in 24M or 32k cycles. Thus, though ATF isn't really so involved in bringing up the GPU, ATF should probably manage the counts for everything so it can also manage the 24M / 32k choice. * It turns out that (right now) 24M mode is broken on rk3399 and not being used. That means that the count the kernel was programming in (24) was not 1 us (which it seems was intended) but was actually .75 ms * On rk3399 there are actually 2 separate registers for setting CPU up/down time plus 1 register for GPU up/down time. The curent kernel code actually was putting the register for the "little" cores in the "CPU" slot and the register for the "big" cores in the "GPU" slot. It was never initting the GPU counts. Note: this change assumes that ATF will actually set these values at boot, as I'm proposing in <http://crosreview.com/372381>. Signed-off-by: Douglas Anderson <dianders@chromium.org> [ATF change has landed] Signed-off-by: Heiko Stuebner <heiko@sntech.de>
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