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Date:   Fri, 13 Sep 2019 08:32:45 -0500
From:   Benoit Parrot <bparrot@ti.com>
To:     Hans Verkuil <hverkuil@xs4all.nl>
CC:     Prabhakar Lad <prabhakar.csengg@gmail.com>,
        <linux-media@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [Patch 08/13] media: am437x-vpfe: Maintain a reference to the
 current vpfe_fmt
Message-ID: <20190913133245.6rvajfhlghbocuf4@ti.com>
References: <20190909162743.30114-1-bparrot@ti.com>
 <20190909162743.30114-9-bparrot@ti.com>
 <8b3d5c23-6784-fb1c-5e14-f3759b10aa0b@xs4all.nl>
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Hans Verkuil <hverkuil@xs4all.nl> wrote on Fri [2019-Sep-13 15:14:45 +0200]:
> On 9/9/19 6:27 PM, Benoit Parrot wrote:
> > Keep a reference to the currently selected struct vpfe_fmt * object.
> > By doing so we rename the current struct v4l2_format * member from
> > fmt to v_fmt.
> > The added struct vpfe_fmt * reference is set to "const" so we also
> > constify all accesses and related helper functions.
> 
> This explains what you do, but not why you do it.

Hmm ok I'll rework this a bit.

> 
> And I think fmt vs v_fmt is *very* confusing naming.

Well in this case v_fmt stands for "v4l2_fmt" and depending on the function
I was using fmt to either mean a vpfe_fmt pointer or a v4l2_format pointer
so tried (and apparently failed) to make it clearer which was which.

> 
> I'd keep fmt as-is, and come up with a different name for the vpfe_fmt
> pointer. ref_vpfe_fmt?
> 
> Regards,
> 
> 	Hans
> 
> > 
> > Signed-off-by: Benoit Parrot <bparrot@ti.com>
> > ---
> >  drivers/media/platform/am437x/am437x-vpfe.c | 88 +++++++++++++--------
> >  drivers/media/platform/am437x/am437x-vpfe.h |  3 +-
> >  2 files changed, 55 insertions(+), 36 deletions(-)
> > 
> > diff --git a/drivers/media/platform/am437x/am437x-vpfe.c b/drivers/media/platform/am437x/am437x-vpfe.c
> > index e76dc2b3b7b8..a8f6cf1d06a0 100644
> > --- a/drivers/media/platform/am437x/am437x-vpfe.c
> > +++ b/drivers/media/platform/am437x/am437x-vpfe.c
> > @@ -147,8 +147,8 @@ static int
> >  __vpfe_get_format(struct vpfe_device *vpfe,
> >  		  struct v4l2_format *format, unsigned int *bpp);
> >  
> > -static struct vpfe_fmt *find_format_by_code(struct vpfe_device *vpfe,
> > -					    unsigned int code)
> > +static const struct vpfe_fmt *find_format_by_code(struct vpfe_device *vpfe,
> > +						  unsigned int code)
> >  {
> >  	struct vpfe_fmt *fmt;
> >  	unsigned int k;
> > @@ -162,8 +162,8 @@ static struct vpfe_fmt *find_format_by_code(struct vpfe_device *vpfe,
> >  	return NULL;
> >  }
> >  
> > -static struct vpfe_fmt *find_format_by_pix(struct vpfe_device *vpfe,
> > -					   unsigned int pixelformat)
> > +static const struct vpfe_fmt *find_format_by_pix(struct vpfe_device *vpfe,
> > +						 unsigned int pixelformat)
> >  {
> >  	struct vpfe_fmt *fmt;
> >  	unsigned int k;
> > @@ -184,7 +184,7 @@ mbus_to_pix(struct vpfe_device *vpfe,
> >  {
> >  	struct vpfe_subdev_info *sdinfo = vpfe->current_subdev;
> >  	unsigned int bus_width = sdinfo->vpfe_param.bus_width;
> > -	struct vpfe_fmt *fmt;
> > +	const struct vpfe_fmt *fmt;
> >  
> >  	fmt = find_format_by_code(vpfe, mbus->code);
> >  	if (WARN_ON(fmt == NULL)) {
> > @@ -207,7 +207,7 @@ static void pix_to_mbus(struct vpfe_device *vpfe,
> >  			struct v4l2_pix_format *pix_fmt,
> >  			struct v4l2_mbus_framefmt *mbus_fmt)
> >  {
> > -	struct vpfe_fmt *fmt;
> > +	const struct vpfe_fmt *fmt;
> >  
> >  	fmt = find_format_by_pix(vpfe, pix_fmt->pixelformat);
> >  	if (!fmt) {
> > @@ -990,10 +990,10 @@ static int vpfe_config_ccdc_image_format(struct vpfe_device *vpfe)
> >  	vpfe_dbg(2, vpfe, "vpfe_config_ccdc_image_format\n");
> >  
> >  	vpfe_dbg(1, vpfe, "pixelformat: %s\n",
> > -		print_fourcc(vpfe->fmt.fmt.pix.pixelformat));
> > +		print_fourcc(vpfe->v_fmt.fmt.pix.pixelformat));
> >  
> >  	if (vpfe_ccdc_set_pixel_format(&vpfe->ccdc,
> > -			vpfe->fmt.fmt.pix.pixelformat) < 0) {
> > +			vpfe->v_fmt.fmt.pix.pixelformat) < 0) {
> >  		vpfe_err(vpfe, "couldn't set pix format in ccdc\n");
> >  		return -EINVAL;
> >  	}
> > @@ -1001,7 +1001,7 @@ static int vpfe_config_ccdc_image_format(struct vpfe_device *vpfe)
> >  	/* configure the image window */
> >  	vpfe_ccdc_set_image_window(&vpfe->ccdc, &vpfe->crop, vpfe->bpp);
> >  
> > -	switch (vpfe->fmt.fmt.pix.field) {
> > +	switch (vpfe->v_fmt.fmt.pix.field) {
> >  	case V4L2_FIELD_INTERLACED:
> >  		/* do nothing, since it is default */
> >  		ret = vpfe_ccdc_set_buftype(
> > @@ -1043,7 +1043,8 @@ static int vpfe_config_ccdc_image_format(struct vpfe_device *vpfe)
> >  static int vpfe_config_image_format(struct vpfe_device *vpfe,
> >  				    v4l2_std_id std_id)
> >  {
> > -	struct v4l2_pix_format *pix = &vpfe->fmt.fmt.pix;
> > +	const struct vpfe_fmt *fmt;
> > +	struct v4l2_pix_format *pix = &vpfe->v_fmt.fmt.pix;
> >  	int i, ret;
> >  
> >  	for (i = 0; i < ARRAY_SIZE(vpfe_standards); i++) {
> > @@ -1078,10 +1079,18 @@ static int vpfe_config_image_format(struct vpfe_device *vpfe,
> >  	else
> >  		pix->field = V4L2_FIELD_NONE;
> >  
> > -	ret = __vpfe_get_format(vpfe, &vpfe->fmt, &vpfe->bpp);
> > +	ret = __vpfe_get_format(vpfe, &vpfe->v_fmt, &vpfe->bpp);
> >  	if (ret)
> >  		return ret;
> >  
> > +	fmt = find_format_by_pix(vpfe, pix->pixelformat);
> > +	if (!fmt) {
> > +		vpfe_dbg(3, vpfe, "Invalid pixel code: %4.4s\n",
> > +			 (char *)&pix->pixelformat);
> > +		return -EINVAL;
> > +	}
> > +	vpfe->fmt = fmt;
> > +
> >  	/* Update the crop window based on found values */
> >  	vpfe->crop.width = pix->width;
> >  	vpfe->crop.height = pix->height;
> > @@ -1227,7 +1236,7 @@ static inline void vpfe_schedule_bottom_field(struct vpfe_device *vpfe)
> >  static inline void vpfe_process_buffer_complete(struct vpfe_device *vpfe)
> >  {
> >  	vpfe->cur_frm->vb.vb2_buf.timestamp = ktime_get_ns();
> > -	vpfe->cur_frm->vb.field = vpfe->fmt.fmt.pix.field;
> > +	vpfe->cur_frm->vb.field = vpfe->v_fmt.fmt.pix.field;
> >  	vpfe->cur_frm->vb.sequence = vpfe->sequence++;
> >  	vb2_buffer_done(&vpfe->cur_frm->vb.vb2_buf, VB2_BUF_STATE_DONE);
> >  	vpfe->cur_frm = vpfe->next_frm;
> > @@ -1296,7 +1305,7 @@ static void vpfe_handle_interlaced_irq(struct vpfe_device *vpfe,
> >  static irqreturn_t vpfe_isr(int irq, void *dev)
> >  {
> >  	struct vpfe_device *vpfe = (struct vpfe_device *)dev;
> > -	enum v4l2_field field = vpfe->fmt.fmt.pix.field;
> > +	enum v4l2_field field = vpfe->v_fmt.fmt.pix.field;
> >  	int intr_status, stopping = vpfe->stopping;
> >  
> >  	intr_status = vpfe_reg_read(&vpfe->ccdc, VPFE_IRQ_STS);
> > @@ -1397,7 +1406,7 @@ static int __vpfe_get_format(struct vpfe_device *vpfe,
> >  		mbus_to_pix(vpfe, &mbus_fmt, &format->fmt.pix, bpp);
> >  	}
> >  
> > -	format->type = vpfe->fmt.type;
> > +	format->type = vpfe->v_fmt.type;
> >  
> >  	vpfe_dbg(1, vpfe,
> >  		 "%s size %dx%d (%s) bytesperline = %d, size = %d, bpp = %d\n",
> > @@ -1434,7 +1443,7 @@ static int __vpfe_set_format(struct vpfe_device *vpfe,
> >  	v4l2_fill_pix_format(&format->fmt.pix, &fmt.format);
> >  	mbus_to_pix(vpfe, &fmt.format, &format->fmt.pix, bpp);
> >  
> > -	format->type = vpfe->fmt.type;
> > +	format->type = vpfe->v_fmt.type;
> >  
> >  	vpfe_dbg(1, vpfe,
> >  		 "%s size %dx%d (%s) bytesperline = %d, size = %d, bpp = %d\n",
> > @@ -1452,7 +1461,7 @@ static int vpfe_g_fmt(struct file *file, void *priv,
> >  
> >  	vpfe_dbg(2, vpfe, "vpfe_g_fmt\n");
> >  
> > -	*fmt = vpfe->fmt;
> > +	*fmt = vpfe->v_fmt;
> >  
> >  	return 0;
> >  }
> > @@ -1496,9 +1505,10 @@ static int vpfe_try_fmt(struct file *file, void *priv,
> >  }
> >  
> >  static int vpfe_s_fmt(struct file *file, void *priv,
> > -		      struct v4l2_format *fmt)
> > +		      struct v4l2_format *f)
> >  {
> >  	struct vpfe_device *vpfe = video_drvdata(file);
> > +	const struct vpfe_fmt *fmt;
> >  	struct v4l2_format format;
> >  	unsigned int bpp;
> >  	int ret;
> > @@ -1515,25 +1525,32 @@ static int vpfe_s_fmt(struct file *file, void *priv,
> >  	if (ret)
> >  		return ret;
> >  
> > -
> > -	if (!cmp_v4l2_format(fmt, &format)) {
> > +	if (!cmp_v4l2_format(f, &format)) {
> >  		/* Sensor format is different from the requested format
> >  		 * so we need to change it
> >  		 */
> > -		ret = __vpfe_set_format(vpfe, fmt, &bpp);
> > +		ret = __vpfe_set_format(vpfe, f, &bpp);
> >  		if (ret)
> >  			return ret;
> >  	} else /* Just make sure all of the fields are consistent */
> > -		*fmt = format;
> > +		*f = format;
> > +
> > +	fmt = find_format_by_pix(vpfe, f->fmt.pix.pixelformat);
> > +	if (!fmt) {
> > +		vpfe_dbg(3, vpfe, "Invalid pixel code: %4.4s, This should not happen!!\n",
> > +			 (char *)&f->fmt.pix.pixelformat);
> > +		return -EINVAL;
> > +	}
> >  
> >  	/* First detach any IRQ if currently attached */
> >  	vpfe_detach_irq(vpfe);
> > -	vpfe->fmt = *fmt;
> > +	vpfe->v_fmt = *f;
> >  	vpfe->bpp = bpp;
> > +	vpfe->fmt = fmt;
> >  
> >  	/* Update the crop window based on found values */
> > -	vpfe->crop.width = fmt->fmt.pix.width;
> > -	vpfe->crop.height = fmt->fmt.pix.height;
> > +	vpfe->crop.width = f->fmt.pix.width;
> > +	vpfe->crop.height = f->fmt.pix.height;
> >  
> >  	/* set image capture parameters in the ccdc */
> >  	return vpfe_config_ccdc_image_format(vpfe);
> > @@ -1547,7 +1564,7 @@ static int vpfe_enum_size(struct file *file, void  *priv,
> >  	struct vpfe_subdev_info *sdinfo;
> >  	struct v4l2_mbus_framefmt mbus;
> >  	struct v4l2_pix_format pix;
> > -	struct vpfe_fmt *fmt;
> > +	const struct vpfe_fmt *fmt;
> >  	int ret;
> >  
> >  	vpfe_dbg(2, vpfe, "vpfe_enum_size\n");
> > @@ -1850,7 +1867,7 @@ static int vpfe_queue_setup(struct vb2_queue *vq,
> >  			    unsigned int sizes[], struct device *alloc_devs[])
> >  {
> >  	struct vpfe_device *vpfe = vb2_get_drv_priv(vq);
> > -	unsigned size = vpfe->fmt.fmt.pix.sizeimage;
> > +	unsigned int size = vpfe->v_fmt.fmt.pix.sizeimage;
> >  
> >  	if (vq->num_buffers + *nbuffers < 3)
> >  		*nbuffers = 3 - vq->num_buffers;
> > @@ -1886,12 +1903,12 @@ static int vpfe_buffer_prepare(struct vb2_buffer *vb)
> >  	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> >  	struct vpfe_device *vpfe = vb2_get_drv_priv(vb->vb2_queue);
> >  
> > -	vb2_set_plane_payload(vb, 0, vpfe->fmt.fmt.pix.sizeimage);
> > +	vb2_set_plane_payload(vb, 0, vpfe->v_fmt.fmt.pix.sizeimage);
> >  
> >  	if (vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0))
> >  		return -EINVAL;
> >  
> > -	vbuf->field = vpfe->fmt.fmt.pix.field;
> > +	vbuf->field = vpfe->v_fmt.fmt.pix.field;
> >  
> >  	return 0;
> >  }
> > @@ -2116,11 +2133,12 @@ vpfe_s_selection(struct file *file, void *fh, struct v4l2_selection *s)
> >  	s->r = vpfe->crop = r;
> >  
> >  	vpfe_ccdc_set_image_window(&vpfe->ccdc, &r, vpfe->bpp);
> > -	vpfe->fmt.fmt.pix.width = r.width;
> > -	vpfe->fmt.fmt.pix.height = r.height;
> > -	vpfe->fmt.fmt.pix.bytesperline = vpfe_ccdc_get_line_length(&vpfe->ccdc);
> > -	vpfe->fmt.fmt.pix.sizeimage = vpfe->fmt.fmt.pix.bytesperline *
> > -						vpfe->fmt.fmt.pix.height;
> > +	vpfe->v_fmt.fmt.pix.width = r.width;
> > +	vpfe->v_fmt.fmt.pix.height = r.height;
> > +	vpfe->v_fmt.fmt.pix.bytesperline =
> > +		vpfe_ccdc_get_line_length(&vpfe->ccdc);
> > +	vpfe->v_fmt.fmt.pix.sizeimage = vpfe->v_fmt.fmt.pix.bytesperline *
> > +						vpfe->v_fmt.fmt.pix.height;
> >  
> >  	vpfe_dbg(1, vpfe, "cropped (%d,%d)/%dx%d of %dx%d\n",
> >  		 r.left, r.top, r.width, r.height, cr.width, cr.height);
> > @@ -2156,7 +2174,7 @@ static long vpfe_ioctl_default(struct file *file, void *priv,
> >  			return ret;
> >  		}
> >  		ret = vpfe_get_ccdc_image_format(vpfe,
> > -						 &vpfe->fmt);
> > +						 &vpfe->v_fmt);
> >  		if (ret < 0) {
> >  			vpfe_dbg(2, vpfe,
> >  				"Invalid image format at CCDC\n");
> > @@ -2309,7 +2327,7 @@ static int vpfe_probe_complete(struct vpfe_device *vpfe)
> >  	spin_lock_init(&vpfe->dma_queue_lock);
> >  	mutex_init(&vpfe->lock);
> >  
> > -	vpfe->fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> > +	vpfe->v_fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> >  
> >  	/* set first sub device as current one */
> >  	vpfe->current_subdev = &vpfe->cfg->sub_devs[0];
> > diff --git a/drivers/media/platform/am437x/am437x-vpfe.h b/drivers/media/platform/am437x/am437x-vpfe.h
> > index 6f25750f84e4..64a25bf720e4 100644
> > --- a/drivers/media/platform/am437x/am437x-vpfe.h
> > +++ b/drivers/media/platform/am437x/am437x-vpfe.h
> > @@ -280,7 +280,8 @@ struct vpfe_device {
> >  	/* Pointer pointing to next v4l2_buffer */
> >  	struct vpfe_cap_buffer *next_frm;
> >  	/* Used to store pixel format */
> > -	struct v4l2_format fmt;
> > +	const struct vpfe_fmt *fmt;
> > +	struct v4l2_format v_fmt;
> >  	/* Used to store current bytes per pixel based on current format */
> >  	unsigned int bpp;
> >  	struct vpfe_fmt	*active_fmt[VPFE_MAX_ACTIVE_FMT];
> > 
>