Cannot enable flexcan1 on i.MX95 EVK

[nasm1th]

We have the i.MX95 EVK (IMX95LPD5EVK-19 from NXP, not the 3rd-party EVKs) and are attempting to enable and test the flexcan interfaces brought out on the board. I have successfully verified that flexcan2 works as expected. However, when I attempt to enable flexcan1 (and disable the micfil node in the device tree), I get errors on boot and the driver fails to load:

[ 9.210952] scmi-pinctrl-imx scmi_dev.8: Error set config -13
[ 9.216959] scmi-pinctrl-imx scmi_dev.8: pin_config_set op failed for pin 121
[ 9.225258] flexcan 443a0000.can: Error applying setting, reverse things back
[ 9.235302] clk: failed to reparent can1 to syspll1_pfd1_di: -1
[ 9.248023] Internal error: synchronous external abort: 0000000096000010 [#1] PREEMPT SMP
[ 9.256197] Modules linked in: crct10dif_ce cdc_acm polyval_ce polyval_generic flexcan(+) rpmsg_ctrl can_dev rpmsg_char pwm_fan fuse
[ 9.268114] CPU: 1 UID: 0 PID: 249 Comm: (udev-worker) Tainted: G M 6.12.49-lts-next-gdf24f9428e38 #1
[ 9.278706] Tainted: [M]=MACHINE_CHECK
[ 9.278709] Hardware name: [redacted]
[ 9.278712] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 9.278717] pc : flexcan_read_le+0x0/0x18 [flexcan]
[ OK 9.298522] lr : flexcan_probe+0x404/0x7d0 [flexcan]
m] Created slice Slice /system/tee-supplicant.
[ 9.310317] sp : ffff8000824e3810
[ 9.313619] x29: ffff8000824e3840 x28: ffff800083230000 x27: ffff2eebc1fc9300
[ 9.320743] x26: ffff2eebc1fc9360 x25: ffff800083230000 x24: ffff2eebced00000
[ 9.327867] x23: ffff2eebc020edc0 x22: ffff2eebc020ec10 x21: ffff800083230000
[ 9.334991] x20: ffff2eebc020ec00 x19: ffff2eebced009c0 x18: 0000000000000001
[ 9.342115] x17: 0000487632eeb000 x16: ffffb58984227000 x15: 0000000000000000
[ 9.349239] x14: 000000000000022d x13: 0000000000000000 x12: 0000000000000000
[ 9.356363] x11: 0000000000000001 x10: fffffffff80082c8 x9 : 0000000000000004
[ 9.363494] x8 : 0101010101010101 x7 : 00000000016e3600 x6 : 0000000000000017
[ 9.363501] x5 : 0000000000000000 x4 : ffff2eebc49f3300 x3 : 0000000000000000
[ 9.363507] x2 : ffffb5898c79f0d8 x1 : ffffb5898422400c x0 : ffff800083230000
[ OK ] Reached target Hardware activated USB gadget.
[ 9.391879] Call trace:
[ 9.394314] flexcan_read_le+0x0/0x18 [flexcan]
[ 9.398845] platform_probe+0x68/0xdc
[ 9.402504] really_probe+0xbc/0x2bc
[ 9.406082] __driver_probe_device+0x78/0x120
[ 9.410425] driver_probe_device+0x3c/0x174
[ 9.414594] __driver_attach+0x90/0x1a0
[ 9.418416] bus_for_each_dev+0x7c/0xdc
[ 9.422247] driver_attach+0x24/0x30
[ 9.425809] bus_add_driver+0xe4/0x208
[ 9.429553] driver_register+0x68/0x124
[ 9.433383] __platform_driver_register+0x24/0x30
[ 9.438072] flexcan_driver_init+0x20/0xfdc [flexcan]
[ 9.443123] do_one_initcall+0x60/0x1d4
[ 9.446947] do_init_module+0x54/0x1fc
[ 9.450691] load_module+0x1910/0x1ec4
[ 9.454429] init_module_from_file+0x88/0xcc
[ 9.454436] __arm64_sys_finit_module+0x1c0/0x324
[ 9.454442] invoke_syscall+0x48/0x104
[ 9.467148] el0_svc_common.constprop.0+0xc0/0xe0
[ 9.467155] do_el0_svc+0x1c/0x28
Starting TEE Supplicant on teepriv0...
[ 9.467160] el0_svc+0x30/0x100
[ 9.483771] el0t_64_sync_handler+0x120/0x12c
[ 9.483776] el0t_64_sync+0x190/0x194
[ 9.483785] Code: d503201f d5033ebf b9000020 d65f03c0 (b9400000)
[ 9.483789] ---[ end trace 0000000000000000 ]---

I have been unable to find a way to get this to work as expected despite the SW9 DIP switch 3 being set to on/CAN.

Is there something I am missing here that is required to get the internal and external muxing to properly route CAN to the flexcan1 peripheral?

[JosephAtNXP]

Hi,

Thank you for your interest in NXP Semiconductor products,

For me, disabling MICFIL would be enough, just make sure you are disabling it in the DTB that U-boot selects with fdtfile environment variable and that you are updating boot partition with that DTB. Just for the sake of trying, I would remove MICFIL nodes and its pin-ctrl nodes.

Please update if you can see the green LED turn on?

Regards

[nasm1th · Accepted solution]

Hi,

I managed to figure this out after digging around a lot more.

It seems that the i.MX95-EVK's system manager image (running on the M33 core) by default limits access to the FlexCAN1 peripheral to only the M7 core. As seen above I'm attempting to access this from Linux (on the A55 cores), so I had to add a custom board to the imx-system-manager recipe in our Yocto distribution to get this to work.

Was this called out somewhere in the EVK's documentation, or is this a missing piece of critical information?

[ArcherLang]

Confirmed:

CAN_FD1 is physically routed to the carrier board CAN transceiver and
must be accessible from the A55 (Linux) domain. Without this change,
the kernel gets EACCES (-13) on pin_config_set for the CAN1 pads
(pdmbitstream0/pdmclk ALT6) and a synchronous external abort when
trying to access the CAN_FD1 register space at 0x443a0000.

Move CAN_FD1 from LM1 (M7) to LM2 (AP).

---

configs/mx95cpl.cfg | 2 +-

1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configs/mx95cpl.cfg b/configs/mx95cpl.cfg

index e25d144..a000001 100755

--- a/configs/mx95cpl.cfg

+++ b/configs/mx95cpl.cfg

@@ -358,7 +358,6 @@

M7P OWNER # CPUs must be first

-CAN_FD1 OWNER

FSB READONLY

IRQSTEER_M7 OWNER

LPIT1 OWNER

LPTMR1 OWNER

@@ -583,6 +582,7 @@

CAMERA7 OWNER

CAMERA8 OWNER

+CAN_FD1 OWNER

CAN_FD2 OWNER

CAN_FD3 OWNER

CAN_FD4 OWNER

CAN_FD5 OWNER

--

2.34.1

[JosephAtNXP]

Probably documentation can clarify it, I don't think it's misleading but it can advise customers to modify SM if needed.

Thanks for sharing the solution.