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Subject: Re: [PATCH v6 14/14] arm64: dts: Add power controller device node
 of MT8183
From:   Weiyi Lu <weiyi.lu@mediatek.com>
To:     CK Hu <ck.hu@mediatek.com>
CC:     Nicolas Boichat <drinkcat@chromium.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Rob Herring <robh@kernel.org>,
        James Liao <jamesjj.liao@mediatek.com>,
        <srv_heupstream@mediatek.com>, <linux-kernel@vger.kernel.org>,
        Fan Chen <fan.chen@mediatek.com>,
        <linux-mediatek@lists.infradead.org>,
        Yong Wu <yong.wu@mediatek.com>,
        <linux-arm-kernel@lists.infradead.org>
Date:   Mon, 15 Jul 2019 17:07:17 +0800
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         <1560998286-9189-15-git-send-email-weiyi.lu@mediatek.com>
         <1561971461.12937.8.camel@mtksdaap41> <1563178045.17756.5.camel@mtksdaap41>
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On Mon, 2019-07-15 at 16:07 +0800, CK Hu wrote:
> Hi, Weiyi:
> 
> On Mon, 2019-07-01 at 16:57 +0800, CK Hu wrote:
> > Hi, Weiyi:
> > 
> > On Thu, 2019-06-20 at 10:38 +0800, Weiyi Lu wrote:
> > > Add power controller node and smi-common node for MT8183
> > > In scpsys node, it contains clocks and regmapping of
> > > infracfg and smi-common for bus protection.
> > > 
> > > Signed-off-by: Weiyi Lu <weiyi.lu@mediatek.com>
> > > ---
> > >  arch/arm64/boot/dts/mediatek/mt8183.dtsi | 62 ++++++++++++++++++++++++++++++++
> > >  1 file changed, 62 insertions(+)
> > > 
> > > diff --git a/arch/arm64/boot/dts/mediatek/mt8183.dtsi b/arch/arm64/boot/dts/mediatek/mt8183.dtsi
> > > index 08274bf..75c4881 100644
> > > --- a/arch/arm64/boot/dts/mediatek/mt8183.dtsi
> > > +++ b/arch/arm64/boot/dts/mediatek/mt8183.dtsi
> > > @@ -8,6 +8,7 @@
> > >  #include <dt-bindings/clock/mt8183-clk.h>
> > >  #include <dt-bindings/interrupt-controller/arm-gic.h>
> > >  #include <dt-bindings/interrupt-controller/irq.h>
> > > +#include <dt-bindings/power/mt8183-power.h>
> > >  
> > >  / {
> > >  	compatible = "mediatek,mt8183";
> > > @@ -196,6 +197,62 @@
> > >  			#clock-cells = <1>;
> > >  		};
> > >  
> > > +		scpsys: syscon@10006000 {
> > > +			compatible = "mediatek,mt8183-scpsys", "syscon";
> > > +			#power-domain-cells = <1>;
> > > +			reg = <0 0x10006000 0 0x1000>;
> > > +			clocks = <&topckgen CLK_TOP_MUX_AUD_INTBUS>,
> > > +				 <&infracfg CLK_INFRA_AUDIO>,
> > > +				 <&infracfg CLK_INFRA_AUDIO_26M_BCLK>,
> > > +				 <&topckgen CLK_TOP_MUX_MFG>,
> > > +				 <&topckgen CLK_TOP_MUX_MM>,
> > > +				 <&topckgen CLK_TOP_MUX_CAM>,
> > > +				 <&topckgen CLK_TOP_MUX_IMG>,
> > > +				 <&topckgen CLK_TOP_MUX_IPU_IF>,
> > > +				 <&topckgen CLK_TOP_MUX_DSP>,
> > > +				 <&topckgen CLK_TOP_MUX_DSP1>,
> > > +				 <&topckgen CLK_TOP_MUX_DSP2>,
> > > +				 <&mmsys CLK_MM_SMI_COMMON>,
> > > +				 <&mmsys CLK_MM_SMI_LARB0>,
> > > +				 <&mmsys CLK_MM_SMI_LARB1>,
> > > +				 <&mmsys CLK_MM_GALS_COMM0>,
> > > +				 <&mmsys CLK_MM_GALS_COMM1>,
> > > +				 <&mmsys CLK_MM_GALS_CCU2MM>,
> > > +				 <&mmsys CLK_MM_GALS_IPU12MM>,
> > > +				 <&mmsys CLK_MM_GALS_IMG2MM>,
> > > +				 <&mmsys CLK_MM_GALS_CAM2MM>,
> > > +				 <&mmsys CLK_MM_GALS_IPU2MM>,
> 
> I've removed all mmsys clock in scpsys node and display still works, so
> I think these subsys clock could be removed from scpsys node. It's
> reasonable that subsys clock is controlled by subsys device or the
> device use it. In MT2712 [1], the scpsys does not control subsys clock
> and it works, so I think you should remove subsys clock in scpsys device
> node.
> 
> [1]
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/mediatek/mt2712e.dtsi?h=v5.2
> 
> Regards,
> CK
> 

Hello CK,

Sorry, I can't agree with you at all.
I thought you just created an environment where the MM (DISP) power
domain could not be turned on and off properly.
If you delete those mmsys clocks listed, bus protection will not work.
These clocks are used for bus protection that I mentioned in patch [2].
I guess you are now trying to solve the problem that mmsys blocks are
used for probing two drivers. One for the display and another for the
clock. Right?
In the previous test you mentioned, you have affected the registration
of mmsys clock first. This is why you saw the boot failure. I think boot
failure is the real problem I should avoid if mmsys clock cannot probe.

[2] https://patchwork.kernel.org/patch/11005747/

> 
> > 
> > Up to now, MT8183 mmsys has the same resource with another device node:
> > 
> > 		mmsys: syscon@14000000 {
> > 			compatible = "mediatek,mt8183-mmsys", "syscon";
> > 			reg = <0 0x14000000 0 0x1000>;
> > 			#clock-cells = <1>;
> > 		};
> > 
> > 		display_components: dispsys@14000000 {
> > 			compatible = "mediatek,mt8183-display";
> > 			reg = <0 0x14000000 0 0x1000>;
> > 			power-domains = <&scpsys MT8183_POWER_DOMAIN_DISP>;
> > 		};
> > 
> > I think this two node should be merge into one node, so I've try to
> > merge them:
> > 
> > 		mmsys: syscon@14000000 {
> > 			compatible = "mediatek,mt8183-mmsys", "syscon";
> > 			reg = <0 0x14000000 0 0x1000>;
> > 			power-domains = <&scpsys MT8183_POWER_DOMAIN_DISP>;
> > 			#clock-cells = <1>;
> > 		};
> > 
> > But I got a kernel panic when boot,
> > 
> > [    3.458523] Unable to handle kernel paging request at virtual address
> > fffffffffffffdfb
> > [    3.466999] Mem abort info:
> > [    3.470116]   ESR = 0x96000005
> > [    3.473268]   Exception class = DABT (current EL), IL = 32 bits
> > [    3.479375]   SET = 0, FnV = 0
> > [    3.482530]   EA = 0, S1PTW = 0
> > [    3.485785] Data abort info:
> > [    3.488831]   ISV = 0, ISS = 0x00000005
> > [    3.493067]   CM = 0, WnR = 0
> > [    3.496229] swapper pgtable: 4k pages, 39-bit VAs, pgdp =
> > 000000004f8fa26d
> > [    3.503214] [fffffffffffffdfb] pgd=0000000000000000,
> > pud=0000000000000000
> > [    3.510408] Internal error: Oops: 96000005 [#1] PREEMPT SMP
> > [    3.515974] Modules linked in:
> > [    3.519023] Process kworker/0:3 (pid: 106, stack limit =
> > 0x00000000281d0651)
> > [    3.526066] CPU: 0 PID: 106 Comm: kworker/0:3 Tainted: G        W
> > 4.19.43 #208
> > [    3.533974] Hardware name: MediaTek kukui rev1 board (DT)
> > [    3.539374] Workqueue: events deferred_probe_work_func
> > [    3.544507] pstate: 20000005 (nzCv daif -PAN -UAO)
> > [    3.549294] pc : clk_prepare+0x18/0x40
> > [    3.553038] lr : scpsys_clk_enable+0x40/0xb4
> > [    3.557299] sp : ffffff800855b9e0
> > [    3.560606] x29: ffffff800855b9f0 x28: ffffff93e1e5f594
> > [    3.565911] x27: 000000000000000f x26: ffffff93e1e5e9b8
> > [    3.571217] x25: 000000003b9aca00 x24: ffffff800858530c
> > [    3.576522] x23: ffffffffffffffff x22: fffffffffffffdfb
> > [    3.581827] x21: 000000000000000a x20: ffffffccb89aafc8
> > [    3.587132] x19: fffffffffffffdfb x18: 00005a5c77082016
> > [    3.592438] x17: 0000000000000400 x16: 0000000000000001
> > [    3.597743] x15: 0000000000000009 x14: ffffff93e271c908
> > [    3.603048] x13: 0000000000000b22 x12: 0000000000000008
> > [    3.608353] x11: 0000000001d063de x10: 0000000000000008
> > [    3.613659] x9 : 00000000ffffffed x8 : 0000000000000000
> > [    3.618964] x7 : 736d6c2dff7224fe x6 : 0000008000000000
> > [    3.624269] x5 : 0000000000000000 x4 : 0000000080000000
> > [    3.629575] x3 : 002f6d6e74000000 x2 : 0000000000000000
> > [    3.634880] x1 : 000000000000000a x0 : fffffffffffffdfb
> > [    3.640185] Call trace:
> > [    3.642625]  clk_prepare+0x18/0x40
> > [    3.646019]  scpsys_clk_enable+0x40/0xb4
> > [    3.649935]  scpsys_power_on+0x13c/0x304
> > [    3.653850]  scpsys_probe+0xe0/0x5fc
> > [    3.657419]  platform_drv_probe+0x80/0xb0
> > [    3.661420]  really_probe+0x114/0x28c
> > [    3.665075]  driver_probe_device+0x64/0xfc
> > [    3.669164]  __device_attach_driver+0xb8/0xd0
> > [    3.673513]  bus_for_each_drv+0x88/0xd0
> > [    3.677341]  __device_attach+0xac/0x130
> > [    3.681169]  device_initial_probe+0x20/0x2c
> > [    3.685344]  bus_probe_device+0x34/0x90
> > [    3.689172]  deferred_probe_work_func+0x74/0xac
> > [    3.693698]  process_one_work+0x210/0x420
> > [    3.697700]  worker_thread+0x278/0x3e4
> > [    3.701443]  kthread+0x11c/0x12c
> > [    3.704665]  ret_from_fork+0x10/0x18
> > 
> > I'm not really understand what happen, but scpsys and mmsys point to
> > each other in MT8183. Why these two node point to each other in MT8183?
> > If this is really hardware limitation, we need to solve this in driver.
> > If this is not a hardware limitation, I would like to re-organize device
> > tree to prevent this problem.
> > 
> > Regards,
> > CK
> > 
> > 
> > > +				 <&imgsys CLK_IMG_LARB5>,
> > > +				 <&imgsys CLK_IMG_LARB2>,
> > > +				 <&camsys CLK_CAM_LARB6>,
> > > +				 <&camsys CLK_CAM_LARB3>,
> > > +				 <&camsys CLK_CAM_SENINF>,
> > > +				 <&camsys CLK_CAM_CAMSV0>,
> > > +				 <&camsys CLK_CAM_CAMSV1>,
> > > +				 <&camsys CLK_CAM_CAMSV2>,
> > > +				 <&camsys CLK_CAM_CCU>,
> > > +				 <&ipu_conn CLK_IPU_CONN_IPU>,
> > > +				 <&ipu_conn CLK_IPU_CONN_AHB>,
> > > +				 <&ipu_conn CLK_IPU_CONN_AXI>,
> > > +				 <&ipu_conn CLK_IPU_CONN_ISP>,
> > > +				 <&ipu_conn CLK_IPU_CONN_CAM_ADL>,
> > > +				 <&ipu_conn CLK_IPU_CONN_IMG_ADL>;
> > > +			clock-names = "audio", "audio1", "audio2",
> > > +				      "mfg", "mm", "cam",
> > > +				      "isp", "vpu", "vpu1",
> > > +				      "vpu2", "vpu3", "mm-0",
> > > +				      "mm-1", "mm-2", "mm-3",
> > > +				      "mm-4", "mm-5", "mm-6",
> > > +				      "mm-7", "mm-8", "mm-9",
> > > +				      "isp-0", "isp-1", "cam-0",
> > > +				      "cam-1", "cam-2", "cam-3",
> > > +				      "cam-4", "cam-5", "cam-6",
> > > +				      "vpu-0", "vpu-1", "vpu-2",
> > > +				      "vpu-3", "vpu-4", "vpu-5";
> > > +			infracfg = <&infracfg>;
> > > +			smi_comm = <&smi_common>;
> > > +		};
> > > +
> > >  		apmixedsys: syscon@1000c000 {
> > >  			compatible = "mediatek,mt8183-apmixedsys", "syscon";
> > >  			reg = <0 0x1000c000 0 0x1000>;
> > > @@ -260,6 +317,11 @@
> > >  			#clock-cells = <1>;
> > >  		};
> > >  
> > > +		smi_common: smi@14019000 {
> > > +			compatible = "mediatek,mt8183-smi-common", "syscon";
> > > +			reg = <0 0x14019000 0 0x1000>;
> > > +		};
> > > +
> > >  		imgsys: syscon@15020000 {
> > >  			compatible = "mediatek,mt8183-imgsys", "syscon";
> > >  			reg = <0 0x15020000 0 0x1000>;
> > 
> 
>