Re: [PATCH v4 06/11] media: imx: utils: Make imx_media_pixfmt handle variable number of codes

[Steve Longerbeam <slongerbeam@xxxxxxxxx>]

Hi Hans,

On 3/31/20 6:45 AM, Hans Verkuil wrote:
> On 3/29/20 10:59 PM, Steve Longerbeam wrote:
> > From: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> >
> > The imx_media_pixfmt structures includes a codes member that stores
> > media bus codes as a fixed array of 4 integers. The functions dealing
> > with the imx_media_pixfmt structures assume that the array of codes is
> > terminated by a 0 elements. This mechanism is fragile, as demonstrated
> elements -> element
>
> > by several instances of the structure contained 4 non-zero codes.
> contained -> that contained

Will fix above language.

> > Fix this by turning the array into a pointer, and providing an
> > IMX_BUS_FMTS macro to initialize the codes member with a guaranteed 0
> > element at the end.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> >
> > [Fix a NULL deref when derefencing a NULL cc->codes on return from
> >   several calls to imx_media_find_format()]
> > Signed-off-by: Steve Longerbeam <slongerbeam@xxxxxxxxx>
> > ---
> >   drivers/staging/media/imx/imx-media-capture.c |  4 +-
> >   drivers/staging/media/imx/imx-media-utils.c   | 88 +++++++++++--------
> >   drivers/staging/media/imx/imx-media.h         |  2 +-
> >   3 files changed, 53 insertions(+), 41 deletions(-)
> >
> > diff --git a/drivers/staging/media/imx/imx-media-capture.c b/drivers/staging/media/imx/imx-media-capture.c
> > index d60b49ec4fa4..650c53289f6b 100644
> > --- a/drivers/staging/media/imx/imx-media-capture.c
> > +++ b/drivers/staging/media/imx/imx-media-capture.c
> > @@ -95,7 +95,7 @@ static int capture_enum_framesizes(struct file *file, void *fh,
> >   	if (!cc)
> >   		return -EINVAL;
> >   
> > -	fse.code = cc->codes[0];
> > +	fse.code = cc->codes ? cc->codes[0] : 0;
> I'm wondering: wouldn't it be better to have a format without codes point to
> an empty code list containing just 0? That would avoid all the cc->codes checks,
> which are a bit fragile IMHO.


I'll modify this patch to declare a const codes array 'no_bus_fmts', 
containing a single 0 value, that the in-memory-only imx_media_pixfmt 
entries can point to.

> It would be nice in that case if there is a WARN_ON or something during probe
> time that checks that the codes field in pixel_formats[] is never NULL.

I'm not so keen on that idea. How about a comment that the 
in-memory-only entries should point to no_bus_fmts ?


> As an aside: 'cc'? The struct is called imx_media_pixfmt, so I don't offhand see
> what 'cc' stands for.

It's an abbreviation of FourCC. I know, it's obscure and not really 
accurate. I will add a non-functional patch that makes the naming 
consistent, using 'fmt' for imx_media_pixfmt pointers throughout.

Steve


> >   
> >   	ret = v4l2_subdev_call(priv->src_sd, pad, enum_frame_size, NULL, &fse);
> >   	if (ret)
> > @@ -137,7 +137,7 @@ static int capture_enum_frameintervals(struct file *file, void *fh,
> >   	if (!cc)
> >   		return -EINVAL;
> >   
> > -	fie.code = cc->codes[0];
> > +	fie.code = cc->codes ? cc->codes[0] : 0;
> >   
> >   	ret = v4l2_subdev_call(priv->src_sd, pad, enum_frame_interval,
> >   			       NULL, &fie);
> > diff --git a/drivers/staging/media/imx/imx-media-utils.c b/drivers/staging/media/imx/imx-media-utils.c
> > index 981a8b540a3c..da010eef0ae6 100644
> > --- a/drivers/staging/media/imx/imx-media-utils.c
> > +++ b/drivers/staging/media/imx/imx-media-utils.c
> > @@ -7,6 +7,12 @@
> >   #include <linux/module.h>
> >   #include "imx-media.h"
> >   
> > +#define IMX_BUS_FMTS(fmts...)	\
> > +	(const u32[]) {		\
> > +		fmts,		\
> > +		0		\
> > +	}
> > +
> >   /*
> >    * List of supported pixel formats for the subdevs.
> >    */
> > @@ -14,18 +20,18 @@ static const struct imx_media_pixfmt pixel_formats[] = {
> >   	/*** YUV formats start here ***/
> >   	{
> >   		.fourcc	= V4L2_PIX_FMT_UYVY,
> > -		.codes  = {
> > +		.codes  = IMX_BUS_FMTS(
> >   			MEDIA_BUS_FMT_UYVY8_2X8,
> >   			MEDIA_BUS_FMT_UYVY8_1X16
> > -		},
> > +		),
> >   		.cs     = IPUV3_COLORSPACE_YUV,
> >   		.bpp    = 16,
> >   	}, {
> >   		.fourcc	= V4L2_PIX_FMT_YUYV,
> > -		.codes  = {
> > +		.codes  = IMX_BUS_FMTS(
> >   			MEDIA_BUS_FMT_YUYV8_2X8,
> >   			MEDIA_BUS_FMT_YUYV8_1X16
> > -		},
> > +		),
> >   		.cs     = IPUV3_COLORSPACE_YUV,
> >   		.bpp    = 16,
> >   	}, {
> > @@ -57,16 +63,16 @@ static const struct imx_media_pixfmt pixel_formats[] = {
> >   	/*** RGB formats start here ***/
> >   	{
> >   		.fourcc	= V4L2_PIX_FMT_RGB565,
> > -		.codes  = {MEDIA_BUS_FMT_RGB565_2X8_LE},
> > +		.codes  = IMX_BUS_FMTS(MEDIA_BUS_FMT_RGB565_2X8_LE),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 16,
> >   		.cycles = 2,
> >   	}, {
> >   		.fourcc	= V4L2_PIX_FMT_RGB24,
> > -		.codes  = {
> > +		.codes  = IMX_BUS_FMTS(
> >   			MEDIA_BUS_FMT_RGB888_1X24,
> >   			MEDIA_BUS_FMT_RGB888_2X12_LE
> > -		},
> > +		),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 24,
> >   	}, {
> > @@ -75,7 +81,7 @@ static const struct imx_media_pixfmt pixel_formats[] = {
> >   		.bpp    = 24,
> >   	}, {
> >   		.fourcc	= V4L2_PIX_FMT_XRGB32,
> > -		.codes  = {MEDIA_BUS_FMT_ARGB8888_1X32},
> > +		.codes  = IMX_BUS_FMTS(MEDIA_BUS_FMT_ARGB8888_1X32),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 32,
> >   		.ipufmt = true,
> > @@ -95,91 +101,91 @@ static const struct imx_media_pixfmt pixel_formats[] = {
> >   	/*** raw bayer and grayscale formats start here ***/
> >   	{
> >   		.fourcc = V4L2_PIX_FMT_SBGGR8,
> > -		.codes  = {MEDIA_BUS_FMT_SBGGR8_1X8},
> > +		.codes  = IMX_BUS_FMTS(MEDIA_BUS_FMT_SBGGR8_1X8),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 8,
> >   		.bayer  = true,
> >   	}, {
> >   		.fourcc = V4L2_PIX_FMT_SGBRG8,
> > -		.codes  = {MEDIA_BUS_FMT_SGBRG8_1X8},
> > +		.codes  = IMX_BUS_FMTS(MEDIA_BUS_FMT_SGBRG8_1X8),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 8,
> >   		.bayer  = true,
> >   	}, {
> >   		.fourcc = V4L2_PIX_FMT_SGRBG8,
> > -		.codes  = {MEDIA_BUS_FMT_SGRBG8_1X8},
> > +		.codes  = IMX_BUS_FMTS(MEDIA_BUS_FMT_SGRBG8_1X8),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 8,
> >   		.bayer  = true,
> >   	}, {
> >   		.fourcc = V4L2_PIX_FMT_SRGGB8,
> > -		.codes  = {MEDIA_BUS_FMT_SRGGB8_1X8},
> > +		.codes  = IMX_BUS_FMTS(MEDIA_BUS_FMT_SRGGB8_1X8),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 8,
> >   		.bayer  = true,
> >   	}, {
> >   		.fourcc = V4L2_PIX_FMT_SBGGR16,
> > -		.codes  = {
> > +		.codes  = IMX_BUS_FMTS(
> >   			MEDIA_BUS_FMT_SBGGR10_1X10,
> >   			MEDIA_BUS_FMT_SBGGR12_1X12,
> >   			MEDIA_BUS_FMT_SBGGR14_1X14,
> >   			MEDIA_BUS_FMT_SBGGR16_1X16
> > -		},
> > +		),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 16,
> >   		.bayer  = true,
> >   	}, {
> >   		.fourcc = V4L2_PIX_FMT_SGBRG16,
> > -		.codes  = {
> > +		.codes  = IMX_BUS_FMTS(
> >   			MEDIA_BUS_FMT_SGBRG10_1X10,
> >   			MEDIA_BUS_FMT_SGBRG12_1X12,
> >   			MEDIA_BUS_FMT_SGBRG14_1X14,
> > -			MEDIA_BUS_FMT_SGBRG16_1X16,
> > -		},
> > +			MEDIA_BUS_FMT_SGBRG16_1X16
> > +		),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 16,
> >   		.bayer  = true,
> >   	}, {
> >   		.fourcc = V4L2_PIX_FMT_SGRBG16,
> > -		.codes  = {
> > +		.codes  = IMX_BUS_FMTS(
> >   			MEDIA_BUS_FMT_SGRBG10_1X10,
> >   			MEDIA_BUS_FMT_SGRBG12_1X12,
> >   			MEDIA_BUS_FMT_SGRBG14_1X14,
> > -			MEDIA_BUS_FMT_SGRBG16_1X16,
> > -		},
> > +			MEDIA_BUS_FMT_SGRBG16_1X16
> > +		),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 16,
> >   		.bayer  = true,
> >   	}, {
> >   		.fourcc = V4L2_PIX_FMT_SRGGB16,
> > -		.codes  = {
> > +		.codes  = IMX_BUS_FMTS(
> >   			MEDIA_BUS_FMT_SRGGB10_1X10,
> >   			MEDIA_BUS_FMT_SRGGB12_1X12,
> >   			MEDIA_BUS_FMT_SRGGB14_1X14,
> > -			MEDIA_BUS_FMT_SRGGB16_1X16,
> > -		},
> > +			MEDIA_BUS_FMT_SRGGB16_1X16
> > +		),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 16,
> >   		.bayer  = true,
> >   	}, {
> >   		.fourcc = V4L2_PIX_FMT_GREY,
> > -		.codes = {
> > +		.codes = IMX_BUS_FMTS(
> >   			MEDIA_BUS_FMT_Y8_1X8,
> >   			MEDIA_BUS_FMT_Y10_1X10,
> > -			MEDIA_BUS_FMT_Y12_1X12,
> > -		},
> > +			MEDIA_BUS_FMT_Y12_1X12
> > +		),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 8,
> >   		.bayer  = true,
> >   	}, {
> >   		.fourcc = V4L2_PIX_FMT_Y10,
> > -		.codes = {MEDIA_BUS_FMT_Y10_1X10},
> > +		.codes = IMX_BUS_FMTS(MEDIA_BUS_FMT_Y10_1X10),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 16,
> >   		.bayer  = true,
> >   	}, {
> >   		.fourcc = V4L2_PIX_FMT_Y12,
> > -		.codes = {MEDIA_BUS_FMT_Y12_1X12},
> > +		.codes = IMX_BUS_FMTS(MEDIA_BUS_FMT_Y12_1X12),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 16,
> >   		.bayer  = true,
> > @@ -203,16 +209,16 @@ static const struct imx_media_pixfmt *find_format(u32 fourcc,
> >   			 CS_SEL_YUV : CS_SEL_RGB);
> >   
> >   		if (!(fmt_cs_sel & cs_sel) ||
> > -		    (!allow_non_mbus && !fmt->codes[0]))
> > +		    (!allow_non_mbus && !fmt->codes))
> >   			continue;
> >   
> >   		if (fourcc && fmt->fourcc == fourcc)
> >   			return fmt;
> >   
> > -		if (!code)
> > +		if (!code || !fmt->codes)
> >   			continue;
> >   
> > -		for (j = 0; j < ARRAY_SIZE(fmt->codes) && fmt->codes[j]; j++) {
> > +		for (j = 0; fmt->codes[j]; j++) {
> >   			if (code == fmt->codes[j])
> >   				return fmt;
> >   		}
> > @@ -237,7 +243,7 @@ static int enum_format(u32 *fourcc, u32 *code, u32 index,
> >   			 CS_SEL_YUV : CS_SEL_RGB);
> >   
> >   		if (!(fmt_cs_sel & cs_sel) ||
> > -		    (!allow_non_mbus && !fmt->codes[0]))
> > +		    (!allow_non_mbus && !fmt->codes))
> >   			continue;
> >   
> >   		if (fourcc && index == 0) {
> > @@ -250,7 +256,7 @@ static int enum_format(u32 *fourcc, u32 *code, u32 index,
> >   			continue;
> >   		}
> >   
> > -		for (j = 0; j < ARRAY_SIZE(fmt->codes) && fmt->codes[j]; j++) {
> > +		for (j = 0; fmt->codes[j]; j++) {
> >   			if (index == 0) {
> >   				*code = fmt->codes[j];
> >   				return 0;
> > @@ -296,13 +302,13 @@ EXPORT_SYMBOL_GPL(imx_media_enum_mbus_format);
> >   static const struct imx_media_pixfmt ipu_formats[] = {
> >   	{
> >   		.fourcc = V4L2_PIX_FMT_YUV32,
> > -		.codes  = {MEDIA_BUS_FMT_AYUV8_1X32},
> > +		.codes  = IMX_BUS_FMTS(MEDIA_BUS_FMT_AYUV8_1X32),
> >   		.cs     = IPUV3_COLORSPACE_YUV,
> >   		.bpp    = 32,
> >   		.ipufmt = true,
> >   	}, {
> >   		.fourcc	= V4L2_PIX_FMT_XRGB32,
> > -		.codes  = {MEDIA_BUS_FMT_ARGB8888_1X32},
> > +		.codes  = IMX_BUS_FMTS(MEDIA_BUS_FMT_ARGB8888_1X32),
> >   		.cs     = IPUV3_COLORSPACE_RGB,
> >   		.bpp    = 32,
> >   		.ipufmt = true,
> > @@ -327,7 +333,10 @@ imx_media_find_ipu_format(u32 code, enum codespace_sel cs_sel)
> >   		    (!accept_rgb && fmt->cs == IPUV3_COLORSPACE_RGB))
> >   			continue;
> >   
> > -		for (j = 0; j < ARRAY_SIZE(fmt->codes) && fmt->codes[j]; j++) {
> > +		if (!fmt->codes)
> > +			continue;
> > +
> > +		for (j = 0; fmt->codes[j]; j++) {
> >   			if (code == fmt->codes[j])
> >   				return fmt;
> >   		}
> > @@ -351,7 +360,10 @@ int imx_media_enum_ipu_format(u32 *code, u32 index, enum codespace_sel cs_sel)
> >   		    (!accept_rgb && fmt->cs == IPUV3_COLORSPACE_RGB))
> >   			continue;
> >   
> > -		for (j = 0; j < ARRAY_SIZE(fmt->codes) && fmt->codes[j]; j++) {
> > +		if (!fmt->codes)
> > +			continue;
> > +
> > +		for (j = 0; fmt->codes[j]; j++) {
> >   			if (index == 0) {
> >   				*code = fmt->codes[j];
> >   				return 0;
> > @@ -567,7 +579,7 @@ int imx_media_ipu_image_to_mbus_fmt(struct v4l2_mbus_framefmt *mbus,
> >   	const struct imx_media_pixfmt *fmt;
> >   
> >   	fmt = imx_media_find_format(image->pix.pixelformat, CS_SEL_ANY);
> > -	if (!fmt)
> > +	if (!fmt || !fmt->codes)
> >   		return -EINVAL;
> >   
> >   	memset(mbus, 0, sizeof(*mbus));
> > diff --git a/drivers/staging/media/imx/imx-media.h b/drivers/staging/media/imx/imx-media.h
> > index 652673a703cd..917b4db02985 100644
> > --- a/drivers/staging/media/imx/imx-media.h
> > +++ b/drivers/staging/media/imx/imx-media.h
> > @@ -69,7 +69,7 @@ enum {
> >   
> >   struct imx_media_pixfmt {
> >   	u32     fourcc;
> > -	u32     codes[4];
> > +	const u32 *codes;
> >   	int     bpp;     /* total bpp */
> >   	/* cycles per pixel for generic (bayer) formats for the parallel bus */
> >   	int	cycles;