Re: [PATCH] clk: rockchip: Fix video codec clocks on rk3288

["elaine.zhang" <zhangqing@rock-chips.com>]

hi,

在 2019/4/11 上午7:37, Doug Anderson 写道:
> Hi,
>
> On Wed, Apr 10, 2019 at 11:38 AM Jonas Karlman <jonas@kwiboo.se> wrote:
>> On 2019-04-10 17:45, Doug Anderson wrote:
>>> Hi,
>>>
>>> On Fri, Mar 29, 2019 at 2:55 PM Douglas Anderson <dianders@chromium.org> wrote:
>>>> 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.
>>>>
>>>> Fixes: 4d3e84f99628 ("clk: rockchip: describe aclk_vcodec using the new muxgrf type on rk3288")
>>>> Signed-off-by: Douglas Anderson <dianders@chromium.org>
>>>> ---
>>>> I currently have no way to test the JPEG mem2mem driver, so hopefully
>>>> others can test this and make sure it's happy for them.  I'm just
>>>> happy not to get strange errors at boot anymore.
>>>>
>>>>   drivers/clk/rockchip/clk-rk3288.c | 2 +-
>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>> Any thoughts about this patch?  I'm 99.9% certain it's correct and
>>> it'd be nice to get it landed.  Heiko: I assume you're still
>>> collecting Rockchip clock patches and would be the one to apply it and
>>> (at some point) send a pull request to the clock tree?
>>>
>>> -Doug
>> This clk fix is needed to make MPEG-2 decoding work on my RK3288 Tinker Board using the
>> rockchip vpu patchset and a patch to add RK3288 specific MPEG-2 code [1].
>>
>> Also note that the same change was suggested in a previous patch [2] from by ayaka.
>>
>> If possible please also add the CLK_SET_RATE_PARENT change from [3] in a possible v2,
>> that fixes assigning the aclk_vcodec clk to 400Mhz in the rockchip vpu driver.
>>
>> [1] https://github.com/Kwiboo/linux-rockchip/commit/1f78093e05c7360515a185f48b7c5cb8ba1e3e15
>> [2] https://patchwork.kernel.org/patch/9725553/
>> [3] https://github.com/Kwiboo/linux-rockchip/commit/9216da3f1521a0be5889235abe7fa093a4894160
> Thanks for the pointers!  Now I'm 99.9999% certain that my patch is
> correct instead of just 99.9%.  ;-)
>
> IMO the CLK_SET_RATE_PARENT should probably be a separate patch but it
> does seem like we need it.  ...and actually the patch adding it should
> have a Fixes tag of the same commit.  Prior to that commit the parent
> of "aclk_vcodec" was "aclk_vdpu".  As a gate clock it would
> automatically have CLK_SET_RATE_PARENT so you could easily set the
> rate.  ...and it looks as if the downstream video codec driver in
> Chrome OS relies on this too.
>
> I'm happy to add that in a v2 if Heiko is happy with it.

I also agree with this modification, which is completely correct. Thank 
you for your modification.

(We didn't push for this change because the  GRF_SOC_CON0[7] is setting 
in vcodec driver(RK mainline branch))

>
> -Doug
>
>
>