Hi Steve, Thanks for your work.
I upported most rcar-csi2 patches but a few of them are still pending, an alternating version based on this BSP patch is already on its way. https://patchwork.linuxtv.org/patch/55623/ As a general feedback calling v4l2_subdev_call() for g_std is not the best way to handle this problem in a MC centric driver. There is a discussion about in in earlier versions of the patch mentioned above. On 2019-04-16 16:38:07 -0700, Steve Longerbeam wrote: > The RCAR Gen3 hardware manual doesn't mention that the "Word Count" field > in the MIPI CSI-2 Frame Start packet is really the frame number. FS packets > are short packets, and short packets do not have a WC but rather a 16-bit > data field, and for Frame synchronization packets (FS/FE) the 16-bit data > field contains a frame number. > > Here is a reprinting from the MIPI CSI-2 specification, version 2 > (section 9.1.2 Low Level Protocol Short Packet Format): > > "Figure 42 and Figure 43 show the Low Level Protocol Short Packet > structures for the D-PHY and C-PHY physical layer options, respectively. > For each option, the Short Packet structure matches the Packet Header of > the corresponding Low Level Protocol Long Packet structure with the > exception that the Packet Header Word Count (WC) field shall be replaced > by the Short Packet Data Field...For Frame Synchronization Data Types > the Short Packet Data Field shall be the frame number..." > > Also in section 9.8.1 Frame Synchronization Packets, the CSI-2 spec reads: > > "The behavior of the 16-bit frame number shall be as one of the following > - Frame number is always zero – frame number is inoperative. > - Frame number increments by 1 for every FS packet with the same Virtual > Channel and is periodically reset to one e.g. 1, 2, 1, 2, 1, 2, 1, 2 or > 1, 2, 3, 4, 1, 2, 3, 4" > > So from the above, FLD_NUM in the FLD register matches against the > frame number transmitted by the CSI-2 source in the Frame Start Packet, > and goes as "1,2,1,2,1,2" or "1,2,3,4,...,1,2,3,4". If there is a match, > the RCAR CSI-2 receiver declares the field as the even, e.g. the BOTTOM, > field. > > NTSC transmits bottom/even field first, and PAL and HD transmit top/odd > field first. So fields with a frame number 1 in the CSI-2 Frame Start > Packet are bottom/even fields for NTSC, and frame number 2 are bottom/even > fields for PAL/HD. > > But the above assumes the transmitting CSI-2 sensor is sending frame > numbers in the sequence "1,2,1,2,...". But according to the CSI-2 spec, > sensors are also allowed to send frame numbers that simply increment as > in "1,2,3,4,...". To generalize to catch those cases, set FLD_DET_SEL > to 0x01, which according to the RCAR Gen3 hardware manual means "the > field is detected as the EVEN field when FLD_NUM[0] matches WC[0]". > Then, the even/bottom fields have odd frame numbers for NTSC, and even > frame numbers for PAL (this patch assumes HDMI sources will not > implement .g_std(), so std will be 0 in that case). > > Finally, set the FLD register to non-zero value only if trnsmitter is > sending ALTERNATE fields. > > Signed-off-by: Steve Longerbeam <slongerb...@gmail.com> > --- > drivers/media/platform/rcar-vin/rcar-csi2.c | 37 ++++++++++++++++++--- > 1 file changed, 32 insertions(+), 5 deletions(-) > > diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c > b/drivers/media/platform/rcar-vin/rcar-csi2.c > index a438ec2c218f..c5bee20d7907 100644 > --- a/drivers/media/platform/rcar-vin/rcar-csi2.c > +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c > @@ -67,6 +67,7 @@ struct rcar_csi2; > /* Field Detection Control */ > #define FLD_REG 0x1c > #define FLD_FLD_NUM(n) (((n) & 0xff) << 16) > +#define FLD_FLD_DET_SEL(n) (((n) & 0x3) << 4) > #define FLD_FLD_EN4 BIT(3) > #define FLD_FLD_EN3 BIT(2) > #define FLD_FLD_EN2 BIT(1) > @@ -462,10 +463,11 @@ static int rcsi2_calc_mbps(struct rcar_csi2 *priv, > unsigned int bpp) > return mbps; > } > > -static int rcsi2_start(struct rcar_csi2 *priv) > +static int rcsi2_start(struct rcar_csi2 *priv, struct v4l2_subdev *nextsd) > { > const struct rcar_csi2_format *format; > - u32 phycnt, vcdt = 0, vcdt2 = 0; > + u32 phycnt, vcdt = 0, vcdt2 = 0, fld = 0; > + v4l2_std_id std = 0; > unsigned int i; > int mbps, ret; > > @@ -476,6 +478,10 @@ static int rcsi2_start(struct rcar_csi2 *priv) > /* Code is validated in set_fmt. */ > format = rcsi2_code_to_fmt(priv->mf.code); > > + ret = v4l2_subdev_call(nextsd, video, g_std, &std); > + if (ret < 0 && ret != -ENOIOCTLCMD && ret != -ENODEV) > + return ret; > + > /* > * Enable all supported CSI-2 channels with virtual channel and > * data type matching. > @@ -509,9 +515,30 @@ static int rcsi2_start(struct rcar_csi2 *priv) > rcsi2_reset(priv); > rcsi2_write(priv, PHTC_REG, 0); > > + /* > + * NTSC standard transmits even/bottom field first, then odd/top. > + * PAL standard and interlaced HD transmit odd/top field first, > + * then even/bottom. > + * > + * For CSI-2 sensors that transmit frame numbers (in the CSI-2 > + * Frame Start packet) as "1,2,1,2,..." or "1,2,3,4,5,...", then: > + * > + * - for NTSC, the even/bottom fields have odd frame numbers. > + * - for PAL and HD, the even/bottom fields have even frame numbers. > + */ > + if (priv->mf.field == V4L2_FIELD_ALTERNATE) { > + fld = FLD_FLD_DET_SEL(1) | FLD_FLD_EN4 | FLD_FLD_EN3 | > + FLD_FLD_EN2 | FLD_FLD_EN; > + > + if (std & V4L2_STD_525_60) > + fld |= FLD_FLD_NUM(1); /* NTSC */ > + else > + fld |= FLD_FLD_NUM(0); /* PAL or HD */ > + } > + > /* Configure */ > - rcsi2_write(priv, FLD_REG, FLD_FLD_NUM(2) | FLD_FLD_EN4 | > - FLD_FLD_EN3 | FLD_FLD_EN2 | FLD_FLD_EN); > + rcsi2_write(priv, FLD_REG, fld); > + > rcsi2_write(priv, VCDT_REG, vcdt); > if (vcdt2) > rcsi2_write(priv, VCDT2_REG, vcdt2); > @@ -591,7 +618,7 @@ static int rcsi2_s_stream(struct v4l2_subdev *sd, int > enable) > if (enable && priv->stream_count == 0) { > pm_runtime_get_sync(priv->dev); > > - ret = rcsi2_start(priv); > + ret = rcsi2_start(priv, nextsd); > if (ret) { > pm_runtime_put(priv->dev); > goto out; > -- > 2.17.1 > -- Regards, Niklas Söderlund
