[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <86565478.t9HNV2EDZM@phil>
Date: Fri, 19 Aug 2016 00:03:01 +0200
From: Heiko Stuebner <heiko@...ech.de>
To: Douglas Anderson <dianders@...omium.org>
Cc: linux-rockchip@...ts.infradead.org, zhangqing@...k-chips.com,
wxt@...k-chips.com, zhengxing@...k-chips.com,
dbasehore@...omium.org, shawn.lin@...k-chips.com,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] soc: rockchip: power-domain: Don't (incorrectly) set rk3399 up/down counts
Hi Doug,
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:
somehow this sentence seems to miss some verb or so :-)
> * 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>.
I'd hope to see a link to an ATF github pull request here :-)
But I guess that simply needs some more discussion on your side.
> Signed-off-by: Douglas Anderson <dianders@...omium.org>
change itself looks good to me.
So I guess we'll just need to wait for the counterpart to land in the ATF or
do you know if the poweron-defaults are somewhat sane?
Heiko
Powered by blists - more mailing lists