linux-kernel - Re: [PATCH] drm/rockchip: vop: Correct enabled clocks during setup

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Date:	Tue, 29 Sep 2015 18:58:07 +0800
From:	Yakir Yang <ykk@...k-chips.com>
To:	Sjoerd Simons <sjoerd.simons@...labora.co.uk>,
	Mark Yao <mark.yao@...k-chips.com>
CC:	Heiko Stuebner <heiko@...ech.de>, David Airlie <airlied@...ux.ie>,
	linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	linux-rockchip@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] drm/rockchip: vop: Correct enabled clocks during setup



On 09/29/2015 05:55 PM, Yakir Yang wrote:
>
>
> On 09/29/2015 05:28 PM, Sjoerd Simons wrote:
>> When doing the initial setup both the hclk and the aclk need to be
>> enabled otherwise the board will simply hang. This only occurs when
>> building the vop driver as a module, when its built-in the initial setup

Hmm... My previous test was built-in the vop driver, and just notice that
you say problem only occurred when building the vop driver as module.
That's to say my test was wrong, so I try to do the right things.

But I found that vop driver module and rockchipdrm driver module in
dependency cycles, here are the build message:
     depmod: ERROR: Found 2 modules in dependency cycles!
     depmod: ERROR: Cycle detected: rockchip_drm_vop -> rockchipdrm -> 
rockchip_drm_vop
     Makefile:1054: recipe for target '_modinst_post' failed

And past my Makefile:
vop-y := rockchip_drm_drv.o rockchip_drm_fb.o rockchip_drm_fbdev.o 
rockchip_drm_gem.o
obj-m = rockchip_drm_vop.o vop.o

Very like to know how you handle this dependency cycles :)

Thanks,
- Yakir

>> happens to run before the clock framework shuts of unused clocks
>> (including the aclk).
>>
>> While there also switch to doing prepare and enable in one step rather
>> then separate steps to reduce the amount of code required.
>>
>> Signed-off-by: Sjoerd Simons <sjoerd.simons@...labora.co.uk>
>
> Looks good and test on chromeos-3.14 tree, no problem, so
>
> Tested-by: Yakir Yang <ykk@...k-chips.com>
>
>> ---
>>
>>   drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 36 
>> +++++++++++------------------
>>   1 file changed, 14 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c 
>> b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> index 5d8ae5e..48719df 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> @@ -1575,32 +1575,25 @@ static int vop_initial(struct vop *vop)
>>           return PTR_ERR(vop->dclk);
>>       }
>>   -    ret = clk_prepare(vop->hclk);
>> -    if (ret < 0) {
>> -        dev_err(vop->dev, "failed to prepare hclk\n");
>> -        return ret;
>> -    }
>> -
>>       ret = clk_prepare(vop->dclk);
>>       if (ret < 0) {
>>           dev_err(vop->dev, "failed to prepare dclk\n");
>> -        goto err_unprepare_hclk;
>> +        return ret;
>>       }
>>   -    ret = clk_prepare(vop->aclk);
>> +    /* Enable both the hclk and aclk to setup the vop */
>> +    ret = clk_prepare_enable(vop->hclk);
>>       if (ret < 0) {
>> -        dev_err(vop->dev, "failed to prepare aclk\n");
>> +        dev_err(vop->dev, "failed to prepare/enable hclk\n");
>>           goto err_unprepare_dclk;
>>       }
>>   -    /*
>> -     * enable hclk, so that we can config vop register.
>> -     */
>> -    ret = clk_enable(vop->hclk);
>> +    ret = clk_prepare_enable(vop->aclk);
>>       if (ret < 0) {
>> -        dev_err(vop->dev, "failed to prepare aclk\n");
>> -        goto err_unprepare_aclk;
>> +        dev_err(vop->dev, "failed to prepare/enable aclk\n");
>> +        goto err_disable_hclk;
>>       }
>> +
>>       /*
>>        * do hclk_reset, reset all vop registers.
>>        */
>> @@ -1608,7 +1601,7 @@ static int vop_initial(struct vop *vop)
>>       if (IS_ERR(ahb_rst)) {
>>           dev_err(vop->dev, "failed to get ahb reset\n");
>>           ret = PTR_ERR(ahb_rst);
>> -        goto err_disable_hclk;
>> +        goto err_disable_aclk;
>>       }
>>       reset_control_assert(ahb_rst);
>>       usleep_range(10, 20);
>> @@ -1634,26 +1627,25 @@ static int vop_initial(struct vop *vop)
>>       if (IS_ERR(vop->dclk_rst)) {
>>           dev_err(vop->dev, "failed to get dclk reset\n");
>>           ret = PTR_ERR(vop->dclk_rst);
>> -        goto err_unprepare_aclk;
>> +        goto err_disable_aclk;
>>       }
>>       reset_control_assert(vop->dclk_rst);
>>       usleep_range(10, 20);
>>       reset_control_deassert(vop->dclk_rst);
>>         clk_disable(vop->hclk);
>> +    clk_disable(vop->aclk);
>>         vop->is_enabled = false;
>>         return 0;
>>   +err_disable_aclk:
>> +    clk_disable_unprepare(vop->aclk);
>>   err_disable_hclk:
>> -    clk_disable(vop->hclk);
>> -err_unprepare_aclk:
>> -    clk_unprepare(vop->aclk);
>> +    clk_disable_unprepare(vop->hclk);
>>   err_unprepare_dclk:
>>       clk_unprepare(vop->dclk);
>> -err_unprepare_hclk:
>> -    clk_unprepare(vop->hclk);
>>       return ret;
>>   }
>


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