[PATCH] soc: rockchip: power-domain: Don't (incorrectly) set rk3399 up/down counts
heiko at sntech.de
Mon Sep 26 13:18:42 PDT 2016
Am Donnerstag, 18. August 2016, 11:56:01 CEST schrieb Douglas Anderson:
> 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
> 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 at chromium.org>
applied to my drivers branch for 4.10
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