iMX8QM MIPI CSI2 virtual channel setting

aso — Fri, 29 Sep 2023 00:17:38 GMT

Hello Community!

I am developing an ISP board that connects to iMX8QM MEK.
The hardware configuration diagram is below.
The software is Linux 6.1.22, and the sensor driver is created based on gmsl-max9286.c.

Now I get an exception when starting Linux.
The sensor board outputs virtual channel 2ch via MIPI, and I have an inquiry regarding the kernel 2ch settings.

[ question 1 ]
I changed the kernel dts and sensor driver as shown below, but are there any mistakes in the settings?

dts:

&isi_0 { status = "okay"; cap_device { status = "okay"; }; m2m_device { status = "okay"; }; }; &isi_1 { status = "okay"; cap_device { status = "okay"; }; }; &isi_2 { status = "disabled"; //[sdi] to disabled cap_device { status = "disabled"; //[sdi] to disabled }; }; &isi_3 { status = "disabled"; //[sdi] to disabled cap_device { status = "disabled"; //[sdi] to disabled }; }; &isi_4 { status = "disabled"; //[sdi] to disabled cap_device { status = "disabled"; //[sdi] to disabled }; }; &isi_5 { status = "disabled"; //[sdi] to disabled cap_device { status = "disabled"; //[sdi] to disabled }; }; &isi_6 { status = "disabled"; //[sdi] to disabled cap_device { status = "disabled"; //[sdi] to disabled }; }; &isi_7 { status = "disabled"; //[sdi] to disabled cap_device { status = "disabled"; //[sdi] to disabled }; }; &mipi_csi_0 { #address-cells = <1>; #size-cells = <0>; virtual-channel; status = "okay"; /* Camera 0 MIPI CSI-2 (CSIS0) */ port@0 { reg = <0>; mipi_csi0_ep: endpoint { remote-endpoint = <&max9286_0_ep>; data-lanes = <1 2 3 4>; }; }; }; &i2c_mipi_csi0 { #address-cells = <1>; #size-cells = <0>; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_i2c_mipi_csi0>; clock-frequency = <100000>; status = "okay"; max9286_mipi@6a { compatible = "sdi,isp_mipi"; reg = <0x6a>; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_mipi_csi0>; clocks = <&clk_dummy>; clock-names = "capture_mclk"; mclk = <27000000>; mclk_source = <0>; pwn-gpios = <&lsio_gpio1 27 GPIO_ACTIVE_HIGH>; virtual-channel; status = "okay"; port { max9286_0_ep: endpoint { remote-endpoint = <&mipi_csi0_ep>; data-lanes = <1 2 3 4>; }; }; }; };

senser driver probe function：

#define MIPI_CSI2_SENS_VC0_PAD_SOURCE 0 #define MIPI_CSI2_SENS_VC1_PAD_SOURCE 1 #define MIPI_CSI2_SENS_VC2_PAD_SOURCE 2 #define MIPI_CSI2_SENS_VCX_PADS_NUM 2 struct sensor_data { : struct media_pad pads[MIPI_CSI2_SENS_VCX_PADS_NUM]; : } sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE; sd->entity.function = MEDIA_ENT_F_CAM_SENSOR; max9286_data->pads[MIPI_CSI2_SENS_VC0_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE; max9286_data->pads[MIPI_CSI2_SENS_VC1_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE; retval = media_entity_pads_init(&sd->entity, MIPI_CSI2_SENS_VCX_PADS_NUM, max9286_data->pads);

Linux dmesg:

[ 2.428771] isp_mipi 2-006a: isp_mipi is found, name isp_mipi 2-006a [ 10.169351] imx8_media_dev: module is from the staging directory, the quality is unknown, you have been warned. [ 10.196793] mx8-img-md: Registered mxc_isi.0.capture as /dev/video3 [ 10.214497] mx8-img-md: Registered mxc_isi.1.capture as /dev/video4 [ 10.221031] mx8-img-md: Registered sensor subdevice: isp_mipi_cam 2-006a (1) [ 10.241443] mx8-img-md: created link [mxc_isi.0] => [mxc_isi.0.capture] [ 10.285198] mx8-img-md: created link [mxc-mipi-csi2.0] => [mxc_isi.0] [ 10.304164] mx8-img-md: created link [mxc_isi.1] => [mxc_isi.1.capture] [ 10.323244] mx8-img-md: created link [mxc-mipi-csi2.0] => [mxc_isi.1] [ 10.364732] ------------[ cut here ]------------ [ 10.369366] WARNING: CPU: 0 PID: 337 at drivers/media/mc/mc-entity.c:1021 media_create_pad_link+0x8c/0x220 [ 10.379044] Modules linked in: flexcan(+) can_dev snd_soc_fsl_sai(+) snd_soc_fsl_audmix imx8_media_dev(C+) snd_soc_fsl_asrc snd_soc_fsl_utils snd_soc_fsl_esai caam error imx_dsp_rproc fuse [ 10.395873] CPU: 0 PID: 337 Comm: (udev-worker) Tainted: G C 6.1.22 #51 [ 10.403888] Hardware name: Freescale i.MX8QM MEK (DT) [ 10.408945] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 10.415911] pc : media_create_pad_link+0x8c/0x220 [ 10.420629] lr : media_create_pad_link+0x58/0x220 [ 10.425338] sp : ffff80000c1db6f0 [ 10.428655] x29: ffff80000c1db6f0 x28: ffff000811dcd080 x27: ffff0008119e0880 [ 10.435805] x26: 0000000000000004 x25: 0000000000000040 x24: ffff00081a5d6650 [ 10.442954] x23: 0000000000000002 x22: 0000000000000002 x21: 0000000000000003 [ 10.450096] x20: ffff000811dcd080 x19: ffff0008119e0880 x18: 0000000000000006 [ 10.457245] x17: 730a323d6461705f x16: 6b6e697320323d64 x15: 61705f656372756f [ 10.464386] x14: 7320383639333836 x13: 383d736461705f6d x12: 756e3e2d6b6e6973 [ 10.471527] x11: 20323d736461705f x10: 0000000000000a70 x9 : ffff8000081e329c [ 10.478668] x8 : ffff0008155655d0 x7 : 0000000000000000 x6 : 0000000000000015 [ 10.485809] x5 : ffff0008ff32ea18 x4 : ffff0008ff32ea18 x3 : 0000000000000000 [ 10.492950] x2 : 0000000000000000 x1 : ffff000815564b00 x0 : 0000000000000002 [ 10.500092] Call trace: [ 10.502535] media_create_pad_link+0x8c/0x220 [ 10.506903] subdev_notifier_complete+0x4ac/0x6c0 [imx8_media_dev] [ 10.513106] v4l2_async_nf_try_complete+0x84/0x9c [ 10.517823] __v4l2_async_nf_register+0xe8/0x140 [ 10.522444] v4l2_async_nf_register+0x4c/0x74 [ 10.526805] mxc_md_probe+0x674/0xa40 [imx8_media_dev] [ 10.531957] platform_probe+0x70/0xcc [ 10.535623] really_probe+0xc8/0x3e0 [ 10.539203] __driver_probe_device+0x84/0x190 [ 10.543564] driver_probe_device+0x44/0x120 [ 10.547751] __driver_attach+0xfc/0x204 [ 10.551591] bus_for_each_dev+0x7c/0xe0 [ 10.555431] driver_attach+0x2c/0x40 [ 10.559010] bus_add_driver+0x184/0x240 [ 10.562850] driver_register+0x80/0x13c [ 10.566690] __platform_driver_register+0x30/0x3c [ 10.571399] mxc_md_driver_init+0x28/0x1000 [imx8_media_dev] [ 10.577071] do_one_initcall+0x60/0x2d0 [ 10.580911] do_init_module+0x50/0x1f0 [ 10.584664] load_module+0x1c44/0x2024 [ 10.588418] __do_sys_finit_module+0xac/0x12c [ 10.592779] __arm64_sys_finit_module+0x28/0x34 [ 10.597313] invoke_syscall+0x50/0x120 [ 10.601066] el0_svc_common.constprop.0+0xd4/0xf4 [ 10.605775] do_el0_svc+0x34/0xd0 [ 10.609093] el0_svc+0x2c/0x84 [ 10.612154] el0t_64_sync_handler+0xf4/0x120 [ 10.616426] el0t_64_sync+0x18c/0x190 [ 10.620093] ---[ end trace 0000000000000000 ]--- [ 10.636501] mx8-img-md: subdev_notifier_complete error exit [ 10.642194] mxc-md bus@58000000:camera: Sensor register failed [ 10.648142] mxc-md: probe of bus@58000000:camera failed with error -22

The causes of the exception are as follows.

drivers/media/mc/mc-entity.c:1035

WARN_ON(source_pad >= source->num_pads) ||

This is because source_pad=2, source->num_pads=2.

[ question 2 ]

I think gmsl-max9286.c is virtual channel 4ch. With this 4ch setting, no exception occurs, but is it okay to use the 4ch setting even with 2ch output?

All suggestions welcome.
Best regards.

Re: iMX8QM MIPI CSI2 virtual channel setting

Dhruvit — Tue, 03 Oct 2023 07:36:27 GMT

Hi @aso,

I hope you are doing well.

Have you disabled mipi_csi_1 and i2c_mipi_csi1 nodes also?

There seems to be some issue with the configuration of source pad mappings.

Please share the full device tree.

Thanks & Regards,
Dhruvit Vasavada

Re: iMX8QM MIPI CSI2 virtual channel setting

aso — Wed, 04 Oct 2023 01:48:55 GMT

Hi, @Dhruvit

Thank you for your reply.
Yes, it's disabled.
I have attached a dts file, so please check it.

Best regards.

Re: iMX8QM MIPI CSI2 virtual channel setting

Dhruvit — Thu, 05 Oct 2023 08:58:33 GMT

Hi @aso,

I hope you are doing well.

There seem to be redundant nodes of mipi_csi_0 in shared dts.

It looks like virtual channels are hardcoded to 1 or 4 in imx8-media-dev.c driver.

mipi_vc = (mipi_csi2->vchannel) ? 4 : 1;

One can try changing it in /drivers/staging/media/imx/imx8-media-dev.c

Thanks & Regards,
Dhruvit Vasavada

Re: iMX8QM MIPI CSI2 virtual channel setting

aso — Mon, 09 Oct 2023 23:09:54 GMT

Hi, @Dhruvit

Thanks for your support.
I modified imx8-media-dev.c and succeeded in avoiding the exception.

Now I started Linux and started debugging the sensor driver, but camera capture fails.
I'll post this issue in a separate thread.

Best regards.

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