Re: [RFC PATCH v2 6/6] drm/rockchip: Add dmc notifier in vop driver

[hl <hl@rock-chips.com>]

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Hi Chanwoo Choi,

On 2016年06月22日 15:11, Chanwoo Choi wrote:
> Hi,
>
> On 2016년 06월 06일 19:13, Lin Huang wrote:
>> when in ddr frequency scaling process, vop can not do
>> enable or disable operate, since dcf will base on vop vblank
>> time to do frequency scaling and need to get vop irq if there
>> have vop enabled. So need register to dmc notifier, and we can
>> get the dmc status.
> If you want to know when ddr frequency is chanaged,
> you can use the DEVFREQ_TRANSITION_NOTIFIER notifier[1] (merged to v4.7-rc1)
> which includes the following notification:
> - DEVFREQ_PRECHANGE
> - DEVFREQ_POSTCHANGE	
>
> [1] "PM / devfreq: Add new DEVFREQ_TRANSITION_NOTIFIER notifier"
> - https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0fe3a66410a3ba96679be903f1e287d7a0a264a9
Check the code, if the set target fail, it will not send 
DEVFREQ_POSTCHANGE, but in our case, whether the target
setting sucess or fail, it should send message to vop driver,  tell vop 
driver dmc have finish frequency setting.
>
> Thanks,
> Chanwoo Choi
>
>> Signed-off-by: Lin Huang <hl@rock-chips.com>
>> ---
>>
>> Changes in v2:
>> - None
>>
>> Changes in v1:
>> - use wait_event instead usleep
>>
>>   drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 43 +++++++++++++++++++++++++++--
>>   1 file changed, 41 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> index 1c4d5b5..8286048 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> @@ -31,6 +31,8 @@
>>   #include <linux/reset.h>
>>   #include <linux/delay.h>
>>   
>> +#include <soc/rockchip/rockchip_dmc.h>
>> +
>>   #include "rockchip_drm_drv.h"
>>   #include "rockchip_drm_gem.h"
>>   #include "rockchip_drm_fb.h"
>> @@ -116,6 +118,10 @@ struct vop {
>>   
>>   	const struct vop_data *data;
>>   
>> +	struct notifier_block dmc_nb;
>> +	int dmc_in_process;
>> +	wait_queue_head_t	wait_dmc_queue;
>> +
>>   	uint32_t *regsbak;
>>   	void __iomem *regs;
>>   
>> @@ -426,6 +432,21 @@ static void vop_dsp_hold_valid_irq_disable(struct vop *vop)
>>   	spin_unlock_irqrestore(&vop->irq_lock, flags);
>>   }
>>   
>> +static int dmc_notify(struct notifier_block *nb, unsigned long event,
>> +		      void *data)
>> +{
>> +	struct vop *vop = container_of(nb, struct vop, dmc_nb);
>> +
>> +	if (event == DMCFREQ_ADJUST) {
>> +		vop->dmc_in_process = 1;
>> +	} else if (event == DMCFREQ_FINISH) {
>> +		vop->dmc_in_process = 0;
>> +		wake_up(&vop->wait_dmc_queue);
>> +	}
>> +
>> +	return NOTIFY_OK;
>> +}
>> +
>>   static void vop_enable(struct drm_crtc *crtc)
>>   {
>>   	struct vop *vop = to_vop(crtc);
>> @@ -434,6 +455,13 @@ static void vop_enable(struct drm_crtc *crtc)
>>   	if (vop->is_enabled)
>>   		return;
>>   
>> +	/*
>> +	 * if in dmc scaling frequency process, wait until it finish
>> +	 * use 100ms as timeout time.
>> +	 */
>> +	wait_event_timeout(vop->wait_dmc_queue,
>> +			   !vop->dmc_in_process, HZ / 10);
>> +
>>   	ret = pm_runtime_get_sync(vop->dev);
>>   	if (ret < 0) {
>>   		dev_err(vop->dev, "failed to get pm runtime: %d\n", ret);
>> @@ -485,6 +513,7 @@ static void vop_enable(struct drm_crtc *crtc)
>>   	enable_irq(vop->irq);
>>   
>>   	drm_crtc_vblank_on(crtc);
>> +	rockchip_dmc_get(&vop->dmc_nb);
>>   
>>   	return;
>>   
>> @@ -505,6 +534,13 @@ static void vop_crtc_disable(struct drm_crtc *crtc)
>>   		return;
>>   
>>   	/*
>> +	 * if in dmc scaling frequency process, wait until it finish
>> +	 * use 100ms as timeout time.
>> +	 */
>> +	wait_event_timeout(vop->wait_dmc_queue,
>> +			   !vop->dmc_in_process, HZ / 10);
>> +
>> +	/*
>>   	 * We need to make sure that all windows are disabled before we
>>   	 * disable that crtc. Otherwise we might try to scan from a destroyed
>>   	 * buffer later.
>> @@ -517,7 +553,7 @@ static void vop_crtc_disable(struct drm_crtc *crtc)
>>   		VOP_WIN_SET(vop, win, enable, 0);
>>   		spin_unlock(&vop->reg_lock);
>>   	}
>> -
>> +	rockchip_dmc_put(&vop->dmc_nb);
>>   	drm_crtc_vblank_off(crtc);
>>   
>>   	/*
>> @@ -1243,7 +1279,7 @@ static int vop_create_crtc(struct vop *vop)
>>   		ret = -ENOENT;
>>   		goto err_cleanup_crtc;
>>   	}
>> -
>> +	vop->dmc_nb.notifier_call = dmc_notify;
>>   	init_completion(&vop->dsp_hold_completion);
>>   	init_completion(&vop->wait_update_complete);
>>   	crtc->port = port;
>> @@ -1465,6 +1501,9 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
>>   	/* IRQ is initially disabled; it gets enabled in power_on */
>>   	disable_irq(vop->irq);
>>   
>> +	init_waitqueue_head(&vop->wait_dmc_queue);
>> +	vop->dmc_in_process = 0;
>> +
>>   	ret = vop_create_crtc(vop);
>>   	if (ret)
>>   		return ret;
>>
>
>
>

-- 
Lin Huang


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