Message-ID: <57883FAB.7040203@rock-chips.com>
Date:	Fri, 15 Jul 2016 09:43:07 +0800
From:	Yakir Yang <ykk@...k-chips.com>
To:	Sean Paul <seanpaul@...omium.org>
Cc:	Mark Yao <yzq@...k-chips.com>, Inki Dae <inki.dae@...sung.com>,
	Jingoo Han <jingoohan1@...il.com>,
	Heiko Stuebner <heiko@...ech.de>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-rockchip@...ts.infradead.org, daniel.vetter@...ll.ch,
	emil.l.velikov@...il.com, dianders@...omium.org,
	dri-devel@...ts.freedesktop.org, Tomasz Figa <tfiga@...omium.org>,
	Javier Martinez Canillas <javier@....samsung.com>,
	Stéphane Marchesin <marcheu@...omium.org>,
	Thierry Reding <treding@...dia.com>,
	Dan Carpenter <dan.carpenter@...cle.com>
Subject: Re: [PATCH v4 1/4] drm/rockchip: vop: export line flag function

Sean,

On 07/14/2016 10:46 PM, Sean Paul wrote:
> On Thu, Jul 14, 2016 at 12:15:44PM +0800, Yakir Yang wrote:
>> VOP have integrated a hardware counter which indicate the exact display
>> line that vop is scanning. And if we're interested in a specific line,
>> we can set the line number to vop line_flag register, and then vop would
>> generate a line_flag interrupt for it.
>>
>> For example eDP PSR function is interested in the vertical blanking
>> period, then driver could set the line number to zero.
>>
>> This patch have exported a symbol that allow other driver to listen the
>> line flag event with given timeout limit:
>> -  rockchip_drm_wait_line_flag()
>>
>> Signed-off-by: Yakir Yang <ykk@...k-chips.com>
>> ---
>> Changes in v4:
>> - Avoid the weird behavior in rockchip_drm_wait_line_flag(). (Sean)
>> - Make line_flag_num_x to an array. (Sean)
>> - Remove the unused vop_cfg_done() in vop_line_flag_irq_enable(). (Stephane, reviewed in Google gerrit)
>>      [https://chromium-review.googlesource.com/#/c/349084/33/drivers/gpu/drm/rockchip/rockchip_drm_vop.c@466]
>>
>> Changes in v3:
>> - Export the 'rockchip_drm_wait_line_flag' symbol, and document it.
>> - Add 'line_flag_num_0' for RK3288/RK3036
>> - Remove the notify for waiting line_flag event (Daniel)
>>
>> Changes in v2:
>> - Introduce in v2, split VOP line flag changes out
>>
>>   drivers/gpu/drm/rockchip/rockchip_drm_drv.h |   3 +
>>   drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 118 ++++++++++++++++++++++++++++
>>   drivers/gpu/drm/rockchip/rockchip_drm_vop.h |   2 +
>>   drivers/gpu/drm/rockchip/rockchip_vop_reg.c |   4 +
>>   4 files changed, 127 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
>> index ea39329..239b830 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
>> @@ -70,4 +70,7 @@ int rockchip_drm_dma_attach_device(struct drm_device *drm_dev,
>>   				   struct device *dev);
>>   void rockchip_drm_dma_detach_device(struct drm_device *drm_dev,
>>   				    struct device *dev);
>> +int rockchip_drm_wait_line_flag(struct drm_crtc *crtc, unsigned int line_num,
>> +				unsigned int mstimeout);
>> +
>>   #endif /* _ROCKCHIP_DRM_DRV_H_ */
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> index c8a62a8..69d32f1 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
>> @@ -121,6 +121,8 @@ struct vop {
>>   	/* protected by dev->event_lock */
>>   	struct drm_pending_vblank_event *event;
>>   
>> +	struct completion line_flag_completion;
>> +
>>   	const struct vop_data *data;
>>   
>>   	uint32_t *regsbak;
>> @@ -431,6 +433,71 @@ static void vop_dsp_hold_valid_irq_disable(struct vop *vop)
>>   	spin_unlock_irqrestore(&vop->irq_lock, flags);
>>   }
>>   
>> +/*
>> + * (1) each frame starts at the start of the Vsync pulse which is signaled by
>> + *     the "FRAME_SYNC" interrupt.
>> + * (2) the active data region of each frame ends at dsp_vact_end
>> + * (3) we should program this same number (dsp_vact_end) into dsp_line_frag_num,
>> + *      to get "LINE_FLAG" interrupt at the end of the active on screen data.
>> + *
>> + * VOP_INTR_CTRL0.dsp_line_frag_num = VOP_DSP_VACT_ST_END.dsp_vact_end
>> + * Interrupts
>> + * LINE_FLAG -------------------------------+
>> + * FRAME_SYNC ----+                         |
>> + *                |                         |
>> + *                v                         v
>> + *                | Vsync | Vbp |  Vactive  | Vfp |
>> + *                        ^     ^           ^     ^
>> + *                        |     |           |     |
>> + *                        |     |           |     |
>> + * dsp_vs_end ------------+     |           |     |   VOP_DSP_VTOTAL_VS_END
>> + * dsp_vact_start --------------+           |     |   VOP_DSP_VACT_ST_END
>> + * dsp_vact_end ----------------------------+     |   VOP_DSP_VACT_ST_END
>> + * dsp_total -------------------------------------+   VOP_DSP_VTOTAL_VS_END
>> + */
>> +static bool vop_line_flag_irq_is_enabled(struct vop *vop)
>> +{
>> +	uint32_t line_flag_irq;
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&vop->irq_lock, flags);
>> +
>> +	line_flag_irq = VOP_INTR_GET_TYPE(vop, enable, LINE_FLAG_INTR);
>> +
>> +	spin_unlock_irqrestore(&vop->irq_lock, flags);
>> +
>> +	return !!line_flag_irq;
>> +}
>> +
>> +static void vop_line_flag_irq_enable(struct vop *vop, int line_num)
>> +{
>> +	unsigned long flags;
>> +
>> +	if (WARN_ON(!vop->is_enabled))
>> +		return;
>> +
>> +	spin_lock_irqsave(&vop->irq_lock, flags);
>> +
>> +	VOP_CTRL_SET(vop, line_flag_num[0], line_num);
>> +	VOP_INTR_SET_TYPE(vop, enable, LINE_FLAG_INTR, 1);
>> +
>> +	spin_unlock_irqrestore(&vop->irq_lock, flags);
>> +}
>> +
>> +static void vop_line_flag_irq_disable(struct vop *vop)
>> +{
>> +	unsigned long flags;
>> +
>> +	if (WARN_ON(!vop->is_enabled))
>> +		return;
>> +
>> +	spin_lock_irqsave(&vop->irq_lock, flags);
>> +
>> +	VOP_INTR_SET_TYPE(vop, enable, LINE_FLAG_INTR, 0);
>> +
>> +	spin_unlock_irqrestore(&vop->irq_lock, flags);
>> +}
>> +
>>   static void vop_enable(struct drm_crtc *crtc)
>>   {
>>   	struct vop *vop = to_vop(crtc);
>> @@ -1157,6 +1224,13 @@ static irqreturn_t vop_isr(int irq, void *data)
>>   		ret = IRQ_HANDLED;
>>   	}
>>   
>> +	if (active_irqs & LINE_FLAG_INTR) {
>> +		if (!completion_done(&vop->line_flag_completion))
>> +			complete(&vop->line_flag_completion);
> You still have the completion_done/complete here.
>
> If you just call complete() without checking if it's done, you'll remove the
> race I mentioned in my first review.

Ah, forget to update this one, will send a new v4.1 patch to fix it.

Thanks a lot,
- Yakir

> Sean
>
>> +		active_irqs &= ~LINE_FLAG_INTR;
>> +		ret = IRQ_HANDLED;
>> +	}
>> +
>>   	if (active_irqs & FS_INTR) {
>>   		drm_crtc_handle_vblank(crtc);
>>   		vop_handle_vblank(vop);
>> @@ -1255,6 +1329,7 @@ static int vop_create_crtc(struct vop *vop)
>>   
>>   	init_completion(&vop->dsp_hold_completion);
>>   	init_completion(&vop->wait_update_complete);
>> +	init_completion(&vop->line_flag_completion);
>>   	crtc->port = port;
>>   	rockchip_register_crtc_funcs(crtc, &private_crtc_funcs);
>>   
>> @@ -1411,6 +1486,49 @@ static void vop_win_init(struct vop *vop)
>>   	}
>>   }
>>   
>> +/**
>> + * rockchip_drm_wait_line_flag - acqiure the give line flag event
>> + * @crtc: CRTC to enable line flag
>> + * @line_num: interested line number
>> + * @mstimeout: millisecond for timeout
>> + *
>> + * Driver would hold here until the interested line flag interrupt have
>> + * happened or timeout to wait.
>> + *
>> + * Returns:
>> + * Zero on success, negative errno on failure.
>> + */
>> +int rockchip_drm_wait_line_flag(struct drm_crtc *crtc, unsigned int line_num,
>> +				unsigned int mstimeout)
>> +{
>> +	struct vop *vop = to_vop(crtc);
>> +	unsigned long jiffies_left;
>> +
>> +	if (!crtc || !vop->is_enabled)
>> +		return -ENODEV;
>> +
>> +	if (line_num > crtc->mode.vtotal || mstimeout <= 0)
>> +		return -EINVAL;
>> +
>> +	if (vop_line_flag_irq_is_enabled(vop))
>> +		return -EBUSY;
>> +
>> +	reinit_completion(&vop->line_flag_completion);
>> +	vop_line_flag_irq_enable(vop, line_num);
>> +
>> +	jiffies_left = wait_for_completion_timeout(&vop->line_flag_completion,
>> +						   msecs_to_jiffies(mstimeout));
>> +	vop_line_flag_irq_disable(vop);
>> +
>> +	if (jiffies_left == 0) {
>> +		dev_err(vop->dev, "Timeout waiting for IRQ\n");
>> +		return -ETIMEDOUT;
>> +	}
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL(rockchip_drm_wait_line_flag);
>> +
>>   static int vop_bind(struct device *dev, struct device *master, void *data)
>>   {
>>   	struct platform_device *pdev = to_platform_device(dev);
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.h b/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
>> index ff4f52e..1dbc526 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
>> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
>> @@ -61,6 +61,8 @@ struct vop_ctrl {
>>   	struct vop_reg hpost_st_end;
>>   	struct vop_reg vpost_st_end;
>>   
>> +	struct vop_reg line_flag_num[2];
>> +
>>   	struct vop_reg cfg_done;
>>   };
>>   
>> diff --git a/drivers/gpu/drm/rockchip/rockchip_vop_reg.c b/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
>> index 6f42e56..eea8427 100644
>> --- a/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
>> +++ b/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
>> @@ -122,6 +122,7 @@ static const struct vop_ctrl rk3036_ctrl_data = {
>>   	.hact_st_end = VOP_REG(RK3036_DSP_HACT_ST_END, 0x1fff1fff, 0),
>>   	.vtotal_pw = VOP_REG(RK3036_DSP_VTOTAL_VS_END, 0x1fff1fff, 0),
>>   	.vact_st_end = VOP_REG(RK3036_DSP_VACT_ST_END, 0x1fff1fff, 0),
>> +	.line_flag_num[0] = VOP_REG(RK3036_INT_STATUS, 0xfff, 12),
>>   	.cfg_done = VOP_REG(RK3036_REG_CFG_DONE, 0x1, 0),
>>   };
>>   
>> @@ -221,6 +222,7 @@ static const struct vop_ctrl rk3288_ctrl_data = {
>>   	.vact_st_end = VOP_REG(RK3288_DSP_VACT_ST_END, 0x1fff1fff, 0),
>>   	.hpost_st_end = VOP_REG(RK3288_POST_DSP_HACT_INFO, 0x1fff1fff, 0),
>>   	.vpost_st_end = VOP_REG(RK3288_POST_DSP_VACT_INFO, 0x1fff1fff, 0),
>> +	.line_flag_num[0] = VOP_REG(RK3288_INTR_CTRL0, 0x1fff, 12),
>>   	.cfg_done = VOP_REG(RK3288_REG_CFG_DONE, 0x1, 0),
>>   };
>>   
>> @@ -299,6 +301,8 @@ static const struct vop_ctrl rk3399_ctrl_data = {
>>   	.vact_st_end = VOP_REG(RK3399_DSP_VACT_ST_END, 0x1fff1fff, 0),
>>   	.hpost_st_end = VOP_REG(RK3399_POST_DSP_HACT_INFO, 0x1fff1fff, 0),
>>   	.vpost_st_end = VOP_REG(RK3399_POST_DSP_VACT_INFO, 0x1fff1fff, 0),
>> +	.line_flag_num[0] = VOP_REG(RK3399_LINE_FLAG, 0xffff, 0),
>> +	.line_flag_num[1] = VOP_REG(RK3399_LINE_FLAG, 0xffff, 16),
>>   	.cfg_done = VOP_REG_MASK(RK3399_REG_CFG_DONE, 0x1, 0),
>>   };
>>   
>> -- 
>> 1.9.1
>>
>>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@...ts.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
>

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