Re: [PATCH 13/14] media: rzg2l-cru: Remove the 'state' variable

[Jacopo Mondi <jacopo.mondi@ideasonboard.com>]

Hi Dan

On Mon, Mar 30, 2026 at 12:55:03PM +0100, Dan Scally wrote:
> Hi Jacopo
>
> On 27/03/2026 17:10, Jacopo Mondi wrote:
> > From: Jacopo Mondi <jacopo.mondi+renesas@ideasonboard.com>
> >
> > The cru driver uses a 'state' variable for debugging purpose in the
> > interrupt handler. The state is used to detect invalid usage conditions
> > that are not meant to happen unless the driver has a bug in handling the
> > stop and start conditions.
> >
> > Remove the state variable which seems to be a debugging leftover.
> >
> > Signed-off-by: Jacopo Mondi <jacopo.mondi+renesas@ideasonboard.com>
> > ---
>
> Just one comment near the bottom...
>
> >   .../media/platform/renesas/rzg2l-cru/rzg2l-cru.h   | 15 -----
> >   .../media/platform/renesas/rzg2l-cru/rzg2l-video.c | 74 +---------------------
> >   2 files changed, 3 insertions(+), 86 deletions(-)
> >
> > diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
> > index bc66b0c8c15e..56359491739e 100644
> > --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
> > +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-cru.h
> > @@ -36,20 +36,6 @@ enum rzg2l_csi2_pads {
> >   struct rzg2l_cru_dev;
> > -/**
> > - * enum rzg2l_cru_dma_state - DMA states
> > - * @RZG2L_CRU_DMA_STOPPED:   No operation in progress
> > - * @RZG2L_CRU_DMA_STARTING:  Capture starting up
> > - * @RZG2L_CRU_DMA_RUNNING:   Operation in progress have buffers
> > - * @RZG2L_CRU_DMA_STOPPING:  Stopping operation
> > - */
> > -enum rzg2l_cru_dma_state {
> > -	RZG2L_CRU_DMA_STOPPED = 0,
> > -	RZG2L_CRU_DMA_STARTING,
> > -	RZG2L_CRU_DMA_RUNNING,
> > -	RZG2L_CRU_DMA_STOPPING,
> > -};
> > -
> >   struct rzg2l_cru_csi {
> >   	struct v4l2_async_connection *asd;
> >   	struct v4l2_subdev *subdev;
> > @@ -173,7 +159,6 @@ struct rzg2l_cru_dev {
> >   	struct vb2_v4l2_buffer *queue_buf[RZG2L_CRU_HW_BUFFER_MAX];
> >   	struct list_head buf_list;
> >   	unsigned int sequence;
> > -	enum rzg2l_cru_dma_state state;
> >   	struct v4l2_pix_format format;
> >   };
> > diff --git a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> > index 45b58e2183bf..30424e2b6cc0 100644
> > --- a/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> > +++ b/drivers/media/platform/renesas/rzg2l-cru/rzg2l-video.c
> > @@ -399,8 +399,6 @@ void rzg2l_cru_stop_image_processing(struct rzg2l_cru_dev *cru)
> >   	if (icnms)
> >   		dev_err(cru->dev, "Failed stop HW, something is seriously broken\n");
> > -	cru->state = RZG2L_CRU_DMA_STOPPED;
> > -
> >   	/* Wait until the FIFO becomes empty */
> >   	for (retries = 5; retries > 0; retries--) {
> >   		if (cru->info->fifo_empty(cru))
> > @@ -588,8 +586,6 @@ static int rzg2l_cru_set_stream(struct rzg2l_cru_dev *cru, int on)
> >   static void rzg2l_cru_stop_streaming(struct rzg2l_cru_dev *cru)
> >   {
> > -	cru->state = RZG2L_CRU_DMA_STOPPING;
> > -
> >   	rzg2l_cru_set_stream(cru, 0);
> >   }
> > @@ -601,8 +597,6 @@ irqreturn_t rzg2l_cru_irq(int irq, void *data)
> >   	u32 amnmbs;
> >   	int slot;
> > -	guard(spinlock_irqsave)(&cru->hw_lock);
> > -
> >   	irq_status = rzg2l_cru_read(cru, CRUnINTS);
> >   	if (!irq_status)
> >   		return IRQ_RETVAL(handled);
> > @@ -611,20 +605,9 @@ irqreturn_t rzg2l_cru_irq(int irq, void *data)
> >   	rzg2l_cru_write(cru, CRUnINTS, rzg2l_cru_read(cru, CRUnINTS));
> > -	/* Nothing to do if capture status is 'RZG2L_CRU_DMA_STOPPED' */
> > -	if (cru->state == RZG2L_CRU_DMA_STOPPED) {
> > -		dev_dbg(cru->dev, "IRQ while state stopped\n");
> > -		return IRQ_RETVAL(handled);
> > -	}
> > -
> > -	/* Increase stop retries if capture status is 'RZG2L_CRU_DMA_STOPPING' */
> > -	if (cru->state == RZG2L_CRU_DMA_STOPPING) {
> > -		if (irq_status & CRUnINTS_SFS)
> > -			dev_dbg(cru->dev, "IRQ while state stopping\n");
> > -		return IRQ_RETVAL(handled);
> > -	}
> > +	/* Calculate slot and prepare for new capture. */
> > +	guard(spinlock_irqsave)(&cru->hw_lock);
> > -	/* Prepare for capture and update state */
> >   	amnmbs = rzg2l_cru_read(cru, AMnMBS);
> >   	cru->active_slot = amnmbs & AMnMBS_MBSTS;
> > @@ -637,20 +620,6 @@ irqreturn_t rzg2l_cru_irq(int irq, void *data)
> >   	else
> >   		slot = cru->active_slot - 1;
> > -	/*
> > -	 * To hand buffers back in a known order to userspace start
> > -	 * to capture first from slot 0.
> > -	 */
> > -	if (cru->state == RZG2L_CRU_DMA_STARTING) {
> > -		if (slot != 0) {
> > -			dev_dbg(cru->dev, "Starting sync slot: %d\n", slot);
> > -			return IRQ_RETVAL(handled);
> > -		}
> > -
> > -		dev_dbg(cru->dev, "Capture start synced!\n");
> > -		cru->state = RZG2L_CRU_DMA_RUNNING;
> > -	}
> > -
> >   	/* Capture frame */
> >   	if (cru->queue_buf[slot]) {
> >   		cru->queue_buf[slot]->field = cru->format.field;
> > @@ -678,49 +647,18 @@ irqreturn_t rzg3e_cru_irq(int irq, void *data)
> >   	u32 irq_status;
> >   	int slot;
> > -	guard(spinlock)(&cru->hw_lock);
> > -
> >   	irq_status = rzg2l_cru_read(cru, CRUnINTS2);
> >   	if (!irq_status)
> >   		return IRQ_NONE;
> > -	dev_dbg(cru->dev, "CRUnINTS2 0x%x\n", irq_status);
> > -
> >   	rzg2l_cru_write(cru, CRUnINTS2, rzg2l_cru_read(cru, CRUnINTS2));
> > -	/* Nothing to do if capture status is 'RZG2L_CRU_DMA_STOPPED' */
> > -	if (cru->state == RZG2L_CRU_DMA_STOPPED) {
> > -		dev_dbg(cru->dev, "IRQ while state stopped\n");
> > -		return IRQ_HANDLED;
> > -	}
> > -
> > -	if (cru->state == RZG2L_CRU_DMA_STOPPING) {
> > -		if (irq_status & CRUnINTS2_FExS(0) ||
> > -		    irq_status & CRUnINTS2_FExS(1) ||
> > -		    irq_status & CRUnINTS2_FExS(2) ||
> > -		    irq_status & CRUnINTS2_FExS(3))
> > -			dev_dbg(cru->dev, "IRQ while state stopping\n");
> > -		return IRQ_HANDLED;
> > -	}
> > -
> > +	guard(spinlock)(&cru->hw_lock);
> >   	slot = cru->active_slot;
> >   	cru->active_slot = rzg2l_cru_slot_next(cru, cru->active_slot);
> >   	dev_dbg(cru->dev, "Current written slot: %d\n", slot);
> > -	/*
> > -	 * To hand buffers back in a known order to userspace start
> > -	 * to capture first from slot 0.
> > -	 */
> > -	if (cru->state == RZG2L_CRU_DMA_STARTING) {
> > -		if (slot != 0) {
> > -			dev_dbg(cru->dev, "Starting sync slot: %d\n", slot);
> > -			return IRQ_HANDLED;
> > -		}
> > -		dev_dbg(cru->dev, "Capture start synced!\n");
> > -		cru->state = RZG2L_CRU_DMA_RUNNING;
> > -	}
> > -
> >   	/* Capture frame */
> >   	if (cru->queue_buf[slot]) {
> >   		struct vb2_v4l2_buffer *buf = cru->queue_buf[slot];
> > @@ -730,9 +668,6 @@ irqreturn_t rzg3e_cru_irq(int irq, void *data)
> >   		buf->vb2_buf.timestamp = ktime_get_ns();
> >   		vb2_buffer_done(&buf->vb2_buf, VB2_BUF_STATE_DONE);
> >   		cru->queue_buf[slot] = NULL;
> > -	} else {
> > -		/* Scratch buffer was used, dropping frame. */
> > -		dev_dbg(cru->dev, "Dropping frame %u\n", cru->sequence);
> >   	}
>
> I guess this change was accidental? For the rest:
>

It actually was intentional and I would drop the same comment in
rzg2l_cru_irq() as well as even for debug purposes, using printk for
events that might happen on a per-buffer bases it's not the best idea.

I'll add it to the commit message.


> Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
>
> >   	cru->sequence++;
> > @@ -789,7 +724,6 @@ static int rzg2l_cru_start_streaming_vq(struct vb2_queue *vq, unsigned int count
> >   		goto out;
> >   	}
> > -	cru->state = RZG2L_CRU_DMA_STARTING;
> >   	dev_dbg(cru->dev, "Starting to capture\n");
> >   	return 0;
> > @@ -862,8 +796,6 @@ int rzg2l_cru_dma_register(struct rzg2l_cru_dev *cru)
> >   	spin_lock_init(&cru->hw_lock);
> >   	spin_lock_init(&cru->qlock);
> > -	cru->state = RZG2L_CRU_DMA_STOPPED;
> > -
> >   	for (i = 0; i < RZG2L_CRU_HW_BUFFER_MAX; i++)
> >   		cru->queue_buf[i] = NULL;
> >
>
>