topic Re: MIPI CSI2 - MEM_PRP_VF_MEM question in i.MX Processors

MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Wed, 28 Jan 2015 13:34:17 GMT

Hi everybody,

I am trying to get some video capture working using MIPI CSI2 and I am having the following issue.

I am able to capture video, but the video is in a grid view of 2 x 2. Meaning, the video is shown 4 times, each window smaller, side by side in a grid instead of the normal picture.

I am using "CSI MEM":

static struct v4l2_input mxc_capture_inputs[MXC_V4L2_CAPTURE_NUM_INPUTS] = {

{

.index = 0,

.name = "CSI IC MEM",

.type = V4L2_INPUT_TYPE_CAMERA,

.audioset = 0,

.tuner = 0,

.std = V4L2_STD_UNKNOWN,

.status = 0,

{

.index = 1,

.name = "CSI MEM",

.type = V4L2_INPUT_TYPE_CAMERA,

.audioset = 0,

.tuner = 0,

.std = V4L2_STD_UNKNOWN,

.status = V4L2_IN_ST_NO_POWER,

};

My sensor is outputting YUV422 and I do not need any preprocessing done (don't need to resize the video or rotate it).

But apparently the stream goes through MEM_PRP_VF_MEM somehow, and that is why I get the grid view video in the end.

ipu_init_channel() inits the channel as MEM_PRP_VF_ENC.

How could I not use PRP VF so the YUV422 stream from the sensor is available to v4l2 capture as is?

Thanks

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Thu, 29 Jan 2015 10:29:23 GMT

Here's how the captured image looks like:

Dropbox - 20150129_102941.jpg

That is using V4L2_PIX_FMT_UYVY in my driver.

If I use V4L2_PIX_FMT_YUV420, I get a 2x4 grid.

The driver enabled mipi using datatype:

mipi_csi2_set_datatype(mipi_csi2_info, MIPI_DT_YUV422);

The images are stable, not scrolling, but you can see some slight color issues (seems to be a bit greenish) and the fact that it actually displays the frames in the space of a grid of 2 x 2. Sometimes it displays the entire 4 frames, sometimes like in the picture it displays some of the frames full and the others with some hsync and vsync issues.

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Thu, 29 Jan 2015 15:09:44 GMT

IPUx_CSI0_SENS_CONF is 0x00008A32

IPUx_CSI0_ACT_FRM_SIZE is 0x023F02CF

The above registers look to be good but the issue is there

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Fri, 30 Jan 2015 00:47:55 GMT

On second thought, IPUx_CSI0_SENS_CONF shows the CSI data width is 8 bits. I would have expected that to be 16 bits for YUV422

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Fri, 30 Jan 2015 07:37:19 GMT

From imx6 dual/duad Reference Manual:

37.4.3.2.2

High-speed serial interface - MIPI (Mobile Industry Processor

Interface).

In MIPI interface two values arrive in each cycle. Each value is 8 bit wide, which means

16 MSB bits of the data bus input are treated, while 4 LSB bits are ignored.

When working in this mode, the CSI can handle up to 4 streams of data. Each stream is

identified with DI (data identifier) that includes the virtual channel and the data type of

this stream. Each stream that is handled is defined in registers MIPI_DI0-3. Only the

main stream (MIPI_DI0) can be sent to all destination units while the other streams are

sent only to the SMFC as generic data.

In this mode SENS_DATA_FORMAT and DATA_WIDTH registers are ignored, since

this information is coming to the CSI via the MCT_DI bus.

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

qiang_li-mpu_se — Wed, 04 Feb 2015 07:44:14 GMT

What's the MIPI virtual channel do you use? If it is not 0, please reference to this patch: https://community.freescale.com/docs/DOC-102233

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Wed, 04 Feb 2015 08:10:10 GMT

Hi Qiang,

I use virtual channel 1.

I applied the patch above, but now I get:

ERROR: v4l2 capture: mxc_v4l_dqueue counter 0

VIDIOC_DQBUF failed.

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

qiang_li-mpu_se — Wed, 04 Feb 2015 08:24:44 GMT

Please pay attention to GPR1 or GPR13 setting.

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Wed, 04 Feb 2015 08:34:10 GMT

So,

as I am using virtual channel 1, I do not need to change GPR1 (I am on imx6 quad by the way).

Without your patch I get a grid image, like the one I mentioned in my second comment. With your patch, I get the error above. When I applied your patch, I only did the changes to ipu_capture.c, as I still want my decoder to sent data to imx on IPU1 (first ipu) CSI 1 (so virtual channel 1).

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

shanmugamsundar — Wed, 04 Feb 2015 09:36:51 GMT

Hi Meton,

Are you using gstreamer command to capture the video? If so can you please provide the command line which you used for capturing

Thanks,

shan

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Wed, 04 Feb 2015 09:42:03 GMT

Hi Shan,

I am using mxc_v4l2_tvin

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

shanmugamsundar — Wed, 04 Feb 2015 13:18:04 GMT

Hi Meton,

what are all the arguments you are passing as input to your mxc_v4l2_tvin ?

Is that arguments contains the cap_mode i have check the original file which i downloaded form the net. In that i didn't see any argument like cap_mode

I have also come across with the same error which you are facing, but i used gstreamer, in that i missed the Cap_mode in my command line. so, can you please check by sending cap_mode

For eg:- ./mxc_v4l2_tvin -ow 640 -ow480 -oc 0

oc = cap_mode and 0 is for 640x480 resolution

Thanks,

shan

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Wed, 04 Feb 2015 15:04:56 GMT

Using mxc_v4l2_tvin -ow 640 -ow480 -oc 0 I get the same timeout error with Qiang's patch.

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Wed, 04 Feb 2015 17:13:11 GMT

Any thought to why it goes through MEM_PRP_VF_ENC?

I am using the path CSI -> MEM. But apparently, once the data goes to memory, it goes through PRP VF and I suspect that is why I get that w eird image (wrong color and multiple images instead of one). How can I make it so the PRP is not used?

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Wed, 04 Feb 2015 17:23:36 GMT

Also, that image I get is using bt656 synchronization.

For example, in ov5640_mipi.c driver, it is:

p->u.bt656.clock_curr = ov5640_data.mclk;

So clock_curr is nonzero. Thus, in mxc_v4l2_capture.c:

if (ifparm.u.bt656.clock_curr == 0)

csi_param.clk_mode = IPU_CSI_CLK_MODE_CCIR656_INTERLACED;

else

csi_param.clk_mode = IPU_CSI_CLK_MODE_GATED_CLK;

looks like the gated mode is used for ov5640_mipi..

In my driver, clock_curr is set to zero, so IPU is configured to be in BT 656 interlaced mode.

However, the imx6 Reference Manual states that when using MIPI, non-gated mode must be used. How does it work for ov5640? In my case, I do not have a mclk from imx6 to my video decoder.

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

qiang_li-mpu_se — Thu, 05 Feb 2015 01:33:42 GMT

Your original issue means virtual channel was not set correct on iMX6, so I gave you the patch for not virtual channel 0 case, but that sample code is for virtual channel 3, you should do some modification for virtual channel 1 case.

Your new timeout issue means the patch hasn't been successfully merged, no data coming to IPU CSI side.

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Thu, 05 Feb 2015 04:25:54 GMT

Hi Qiang. My original issue was that the image I receive seems to be going through the PRP and somehow converted to a different format so I get wrong colors and multiple images.

Regarding your patch, I did the changes for virtual channel 1 and get no data. So I am back to my case, wondering how to bypass the PRP.

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

qiang_li-mpu_se — Thu, 05 Feb 2015 06:01:34 GMT

Hi Meton, if you are using the mxc_v4l2_tvin test application, the data path was fixed at CSI->MEM, no PRP will be used.

In fact I had seen the wrong virtual channel case, the captured image is same as yours.

By the way, you'd better enable your camera on virtual channel 0 first.

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Thu, 05 Feb 2015 07:46:55 GMT

Were you using nongated mode, gated or bt656 sync?

I mean, in the driver's ioctl_g_ifparm() do you set p->u.bt656.clock_curr? Depending on that, in mxc_v4l2_capture.c, the timing mode is defined.

The reason I ask is because if I try on virtual channel 0, with clock_curr not set in my driver, I get timeout on vc 0 as well. If I set some non zero value to clock_curr, then it does not timeout but I get very very messy image.

Re: MIPI CSI2 - MEM_PRP_VF_MEM question

meflo — Fri, 06 Feb 2015 08:19:28 GMT

The MIPI clock rate I have is 108 MHz. So I have set DDR at 216 MHz.

Now, if using bt656 synchronization, what should the clock_curr value be in the driver? I do not have the mclk line (master clock) from the imx to the decoder.

I am on kernel 3.0.35

It's not clear on how the non-gated mode is used for MIPI