Subject: Re: [PATCH v6 4/7] drm/rockchip: vop: group vop registers
To: =?UTF-8?Q?Heiko_St=c3=bcbner?= <heiko@sntech.de>
References: <1501049930-5794-1-git-send-email-mark.yao@rock-chips.com>
 <1501049966-6070-1-git-send-email-mark.yao@rock-chips.com>
 <44153824.CqyclESHdT@diego> <10499935.q3BgzX4LKL@diego>
 <597A8D38.3040905@rock-chips.com>
Cc: David Airlie <airlied@linux.ie>, linux-rockchip@lists.infradead.org,
        dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
From: Mark yao <mark.yao@rock-chips.com>
Message-ID: <597AA54D.60706@rock-chips.com>
Date: Fri, 28 Jul 2017 10:45:33 +0800
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Hi Heiko

On 2017年07月28日 09:02, Mark yao wrote:
> Hi Heiko
>
> Thanks for the test.
>
> On 2017年07月27日 18:10, Heiko Stübner wrote:
>> Am Donnerstag, 27. Juli 2017, 11:51:06 CEST schrieb Heiko Stübner:
>>> Hi Mark,
>>>
>>> Am Mittwoch, 26. Juli 2017, 14:19:25 CEST schrieb Mark Yao:
>>>> Grouping the vop registers facilitates make register
>>>> definition clearer, and also is useful for different vop
>>>> reuse the same group register.
>>>>
>>>> Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
>>>> ---
>>>>
>>>>   drivers/gpu/drm/rockchip/rockchip_drm_vop.c |  99
>>>>   ++++++++++++------------
>>>>   drivers/gpu/drm/rockchip/rockchip_drm_vop.h |  60 ++++++++-------
>>>>   drivers/gpu/drm/rockchip/rockchip_vop_reg.c | 112
>>>>
>>>> +++++++++++++++------------- 3 files changed, 144 insertions(+), 127
>>>> deletions(-)
>>> This breaks display support on both rk3036 and rk3288 and I end up
>>> with a null pointer dereference in
>>>
>>> [   10.640297] Unable to handle kernel NULL pointer dereference at virtual
>>> address 00000000 [   10.654430] pgd = c0204000
>>> [   10.657452] [00000000] *pgd=00000000
>>> [   10.661473] Internal error: Oops: 5 [#1] SMP ARM
>>> [   10.666635] Modules linked in: snd_pcm media snd_timer phy_rockchip_dp
>>> snd soundcore rockchipdrm dw_hdmi analogix_dp rtc_rk808 pwm_rockchip
>>> clk_rk808 spi_rockchip [   10.682897] CPU: 2 PID: 143 Comm: kworker/2:2 Not
>>> tainted 4.13.0-rc2-01791-g2b86603d0515 #355 [   10.692430] Hardware name:
>>> Rockchip (Device Tree)
>>> [   10.697692] Workqueue: events deferred_probe_work_func
>>> [   10.702152] Linux video capture interface: v2.00
>>> [   10.708590] task: ee38c800 task.stack: ed2e6000
>>> [   10.713656] PC is at vop_reg_set.constprop.4+0x4/0xa8 [rockchipdrm]
>>> [   10.720668] LR is at vop_bind+0x568/0x8a0 [rockchipdrm]
>> The obvious reason for that is
>>
>>> @@ -164,14 +153,20 @@ static inline uint32_t vop_read_reg(struct vop *vop,
>>> uint32_t base, return (vop_readl(vop, base + reg->offset) >> reg->shift) &
>>> reg->mask; }
>>>
>>> -static inline void vop_mask_write(struct vop *vop, uint32_t offset,
>>> -                  uint32_t mask, uint32_t shift, uint32_t v,
>>> -                  bool write_mask, bool relaxed)
>>> +static void vop_reg_set(struct vop *vop, const struct vop_reg *reg,
>>> +            uint32_t _offset, uint32_t _mask, uint32_t v,
>>> +            const char *reg_name)
>>>   {
>>> -    if (!mask)
>>> +    int offset = reg->offset + _offset;
>>> +    int mask = reg->mask & _mask;
>>> +    int shift = reg->shift;
>
> Does the crash is that using reg->offset/mask/shift before !reg checking?

I reproduce this cause, from objdump, it crash on "int mask = reg->mask & _mask; "
Seems difference gcc has difference behavior, my aarch64 gcc maybe optimize it,
only access when the value be used. I think that is the reason why rk3399 works on my test.

I will fix it at next version.

>
>>> +
>>> +    if (!reg || !reg->mask) {
>>> +        dev_dbg(vop->dev, "Warning: not support %s\n", reg_name);
>>>           return;
>>> +    }
>> where the check for !reg happens after it got already dereferenced.
>> But even with that fixed I end up with
>>
>> on rk3288:
>> [    7.254823] rockchip-vop ff930000.vop: Warning: not support global_regdone_en
>> [    7.262847] rockchip-vop ff930000.vop: Warning: not support gate
>> [    7.269580] rockchip-vop ff930000.vop: Warning: not support gate
>> [    7.302765] rockchip-vop ff940000.vop: Warning: not support global_regdone_en
>> [    7.310758] rockchip-vop ff940000.vop: Warning: not support gate
>> [    7.317475] rockchip-vop ff940000.vop: Warning: not support gate
>> [    7.425724] rockchip-vop ff930000.vop: Warning: not support edp_pin_pol
>> [    7.526298] rockchip-vop ff940000.vop: Warning: not support hdmi_pin_pol
>
> Rk3288 does not support independent pin_pol settings, all output interfaces share the pin_pol register,
> So not support hdmi_pin_pol here is correct.
>
> hdmi pin pol would be set by following register:
>     .pin_pol = VOP_REG(RK3288_DSP_CTRL0, 0xf, 4),
>
>>
>> on rk3036:
>> [   12.389138] rockchip-vop 10118000.vop: Warning: not support global_regdone_en
>> [   12.397324] rockchip-vop 10118000.vop: Warning: not support gate
>> [   12.404165] rockchip-vop 10118000.vop: Warning: not support gate
>> [   13.747361] rockchip-vop 10118000.vop: Warning: not support hdmi_pin_pol
>> [   13.747371] rockchip-vop 10118000.vop: Warning: not support hdmi_en
>> [   13.747379] rockchip-vop 10118000.vop: Warning: not support hpost_st_end
>> [   13.747385] rockchip-vop 10118000.vop: Warning: not support vpost_st_end
>> [   13.747461] rockchip-vop 10118000.vop: Warning: not support src_alpha_ctl
>> [   13.767098] rockchip-vop 10118000.vop: Warning: not support src_alpha_ctl
>> [   13.786060] rockchip-vop 10118000.vop: Warning: not support src_alpha_ctl
>>
>> While reqdone and friends are obviously features of newer vops, at least
>> the hdmi pin-pol is available on both these socs.
>>
>> With this patch applied (and null-ptr fixed) I end up without hdmi output
>> on both socs.
>
> Hmmm, I am confused, from code review, I didn't see what will cause hdmi not work on rk3036 and rk3288,
>
> Give me some time, I try to bringup my popmetal rk3288 board to do the test.
>
> Heiko, Thanks very much for your test.

Hi Heiko

After fix null pointer problem, On rk3288 popmetal board, hdmi works good on my test, Can you double check it?

Thanks.

>
>>
>>
>> Heiko
>>
>> _______________________________________________
>> Linux-rockchip mailing list
>> Linux-rockchip@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-rockchip
>>
>>
>>
>
>


-- 
Ｍark Yao