linux-kernel - Re: [PATCH v2] clk: rockchip: Fix video codec clocks on rk3288

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Date:   Fri, 12 Apr 2019 13:22:31 +0200
From:   Heiko Stübner <heiko@...ech.de>
To:     Douglas Anderson <dianders@...omium.org>
Cc:     Jonas Karlman <jonas@...boo.se>, Tomasz Figa <tfiga@...omium.org>,
        Randy Li <ayaka@...lik.info>,
        Ziyuan Xu <xzy.xu@...k-chips.com>,
        Ezequiel Garcia <ezequiel@...labora.com>,
        ryandcase@...omium.org, Elaine Zhang <zhangqing@...k-chips.com>,
        mka@...omium.org, Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-kernel@...r.kernel.org,
        linux-rockchip@...ts.infradead.org, linux-clk@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2] clk: rockchip: Fix video codec clocks on rk3288

Am Donnerstag, 11. April 2019, 15:55:55 CEST schrieb Douglas Anderson:
> It appears that there is a typo in the rk3288 TRM.  For
> GRF_SOC_CON0[7] it says that 0 means "vepu" and 1 means "vdpu".  It's
> the other way around.
> 
> How do I know?  Here's my evidence:
> 
> 1. Prior to commit 4d3e84f99628 ("clk: rockchip: describe aclk_vcodec
>    using the new muxgrf type on rk3288") we always pretended that we
>    were using "aclk_vdpu" and the comment in the code said that this
>    matched the default setting in the system.  In fact the default
>    setting is 0 according to the TRM and according to reading memory
>    at bootup.  In addition rk3288-based Chromebooks ran like this and
>    the video codecs worked.
> 2. With the existing clock code if you boot up and try to enable the
>    new VIDEO_ROCKCHIP_VPU as a module (and without "clk_ignore_unused"
>    on the command line), you get errors like "failed to get ack on
>    domain 'pd_video', val=0x80208".  After flipping vepu/vdpu things
>    init OK.
> 3. If I export and add both the vepu and vdpu to the list of clocks
>    for RK3288_PD_VIDEO I can get past the power domain errors, but now
>    I freeze when the vpu_mmu gets initted.
> 4. If I just mark the "vdpu" as IGNORE_UNUSED then everything boots up
>    and probes OK showing that somehow the "vdpu" was important to keep
>    enabled.  This is because we were actually using it as a parent.
> 5. After this change I can hack "aclk_vcodec_pre" to parent from
>    "aclk_vepu" using assigned-clocks and the video codec still probes
>    OK.
> 6. Rockchip has said so on the mailing list [1].
> 
> ...so let's fix it.
> 
> Let's also add CLK_SET_RATE_PARENT to "aclk_vcodec_pre" as suggested
> by Jonas Karlman.  Prior to the same commit you could do
> clk_set_rate() on "aclk_vcodec" and it would change "aclk_vdpu".
> That's because "aclk_vcodec" was a simple gate clock (always gets
> CLK_SET_RATE_PARENT) and its direct parent was "aclk_vdpu".  After
> that commit "aclk_vcodec_pre" gets in the way so we need to add
> CLK_SET_RATE_PARENT to it too.
> 
> [1] https://lkml.kernel.org/r/1d17b015-9e17-34b9-baf8-c285dc1957aa@rock-chips.com
> 
> Fixes: 4d3e84f99628 ("clk: rockchip: describe aclk_vcodec using the new muxgrf type on rk3288")
> Suggested-by: Jonas Karlman <jonas@...boo.se>
> Suggested-by: Randy Li <ayaka@...lik.info>
> Signed-off-by: Douglas Anderson <dianders@...omium.org>

applied for 5.2

Thanks
Heiko