linux-kernel - Re: [PATCH 7/9] media: cedrus: Move IRQ maintainance to cedrus_dec

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Date:   Mon, 25 Jun 2018 17:38:10 +0200
From:   Paul Kocialkowski <paul.kocialkowski@...tlin.com>
To:     Maxime Ripard <maxime.ripard@...tlin.com>, hans.verkuil@...co.com,
        acourbot@...omium.org, sakari.ailus@...ux.intel.com,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc:     tfiga@...omium.org, posciak@...omium.org,
        Chen-Yu Tsai <wens@...e.org>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org,
        nicolas.dufresne@...labora.com, jenskuske@...il.com,
        linux-sunxi@...glegroups.com,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH 7/9] media: cedrus: Move IRQ maintainance to
 cedrus_dec_ops

Hi,

On Wed, 2018-06-13 at 16:07 +0200, Maxime Ripard wrote:
> The IRQ handler up until now was hardcoding the use of the MPEG engine to
> read the interrupt status, clear it and disable the interrupts.
> 
> Obviously, that won't work really well with the introduction of new codecs
> that use a separate engine with a separate register set.
> 
> In order to make this more future proof, introduce new decodec operations
> to deal with the interrupt management. The only one missing is the one to
> enable the interrupts in the first place, but that's taken care of by the
> trigger hook for now.

Here's another comment about an issue I just figured out.

> Signed-off-by: Maxime Ripard <maxime.ripard@...tlin.com>
> ---
>  .../sunxi/cedrus/sunxi_cedrus_common.h        |  9 +++++
>  .../platform/sunxi/cedrus/sunxi_cedrus_hw.c   | 21 ++++++------
>  .../sunxi/cedrus/sunxi_cedrus_mpeg2.c         | 33 +++++++++++++++++++
>  3 files changed, 53 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_common.h b/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_common.h
> index c2e2c92d103b..a2a507eb9fc9 100644
> --- a/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_common.h
> +++ b/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_common.h
> @@ -108,7 +108,16 @@ struct sunxi_cedrus_buffer *vb2_to_cedrus_buffer(const struct vb2_buffer *p)
>  	return vb2_v4l2_to_cedrus_buffer(to_vb2_v4l2_buffer(p));
>  }
>  
> +enum sunxi_cedrus_irq_status {
> +	SUNXI_CEDRUS_IRQ_NONE,
> +	SUNXI_CEDRUS_IRQ_ERROR,
> +	SUNXI_CEDRUS_IRQ_OK,
> +};
> +
>  struct sunxi_cedrus_dec_ops {
> +	void (*irq_clear)(struct sunxi_cedrus_ctx *ctx);
> +	void (*irq_disable)(struct sunxi_cedrus_ctx *ctx);
> +	enum sunxi_cedrus_irq_status (*irq_status)(struct sunxi_cedrus_ctx *ctx);
>  	void (*setup)(struct sunxi_cedrus_ctx *ctx,
>  		      struct sunxi_cedrus_run *run);
>  	void (*trigger)(struct sunxi_cedrus_ctx *ctx);
> diff --git a/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_hw.c b/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_hw.c
> index bb46a01214e0..6b97cbd2834e 100644
> --- a/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_hw.c
> +++ b/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_hw.c
> @@ -77,27 +77,28 @@ static irqreturn_t sunxi_cedrus_ve_irq(int irq, void *dev_id)
>  	struct sunxi_cedrus_ctx *ctx;
>  	struct sunxi_cedrus_buffer *src_buffer, *dst_buffer;
>  	struct vb2_v4l2_buffer *src_vb, *dst_vb;
> +	enum sunxi_cedrus_irq_status status;
>  	unsigned long flags;
> -	unsigned int value, status;
>  
>  	spin_lock_irqsave(&dev->irq_lock, flags);
>  
> -	/* Disable MPEG interrupts and stop the MPEG engine */
> -	value = sunxi_cedrus_read(dev, VE_MPEG_CTRL);
> -	sunxi_cedrus_write(dev, value & (~0xf), VE_MPEG_CTRL);
> -
> -	status = sunxi_cedrus_read(dev, VE_MPEG_STATUS);
> -	sunxi_cedrus_write(dev, 0x0000c00f, VE_MPEG_STATUS);
> -	sunxi_cedrus_engine_disable(dev);

This call was dropped from the code reorganization. What it intentional?

IMO, it should be brought back to the irq_disable ops for MPEG2 (and the
same probably applies to H264). Things still seem to work without it,
though, but there might be a difference in terms of standby VPU power
consumption.

Cheers,

Paul

-- 
Paul Kocialkowski, Bootlin (formerly Free Electrons)
Embedded Linux and kernel engineering
https://bootlin.com
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