I would like to use uart4 in imx8mm

[takeshi100]

According to the following web site, I fixed device treee and imx8mm_bl31_setup.c.

But, Kernel panic still was happened.

Is there anything else I should do?

■ web site

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/How-to-use-UART4-on-iMX8M-from-Linux-Use...

■　log

[2025-01-07 19:50:13.705] [ 0.126548] Bus freq driver module loaded
[2025-01-07 19:50:13.705] [ 0.137182] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[2025-01-07 19:50:13.705] [ 0.139992] 30860000.serial: ttymxc0 at MMIO 0x30860000 (irq = 15, base_baud = 5000000) is a IMX
[2025-01-07 19:50:13.705] [ 0.140121] serial serial0: tty port ttymxc0 registered
[2025-01-07 19:50:13.706] [ 0.140547] 30890000.serial: ttymxc1 at MMIO 0x30890000 (irq = 16, base_baud = 1500000) is a IMX
[2025-01-07 19:50:13.722] [ 0.140585] printk: console [ttymxc1] enabled
[2025-01-07 19:50:13.960] [ 1.308725] SError Interrupt on CPU3, code 0x00000000bf000002 -- SError
[2025-01-07 19:50:13.960] [ 1.308737] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 6.6.23-lts-next-gd490f49646f0-dirty #1
[2025-01-07 19:50:13.960] [ 1.308744] Hardware name: FSL i.MX8MM EVK board (DT)
[2025-01-07 19:50:13.960] [ 1.308747] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[2025-01-07 19:50:13.960] [ 1.308754] pc : imx_uart_probe+0x3e4/0x980
[2025-01-07 19:50:13.960] [ 1.308771] lr : imx_uart_probe+0x380/0x980
[2025-01-07 19:50:13.960] [ 1.308783] sp : ffff80008003bb30
[2025-01-07 19:50:13.960] [ 1.308785] x29: ffff80008003bb50 x28: 0000000000000000 x27: ffffb2254bc76068
[2025-01-07 19:50:13.960] [ 1.308799] x26: ffff2141444fd0c0 x25: 0000000000000011 x24: 00000000fffffffa
[2025-01-07 19:50:13.960] [ 1.308809] x23: ffff21414410bc10 x22: 00000000fffffffa x21: ffff21414410bc00
[2025-01-07 19:50:13.960] [ 1.308821] x20: 0000000000000000 x19: ffff2141448e8080 x18: ffffffffffffffff
[2025-01-07 19:50:13.973] [ 1.308832] x17: 1fffe428288813e1 x16: 0000000000000000 x15: ffff80008003b4d0
[2025-01-07 19:50:13.973] [ 1.308844] x14: ffffffffffffffff x13: 0000000000000018 x12: 0101010101010101
[2025-01-07 19:50:13.973] [ 1.308854] x11: 7f7f7f7f7f7f7f7f x10: ffffb6254db29d2f x9 : 0000000000000028
[2025-01-07 19:50:13.973] [ 1.308865] x8 : ffff2141444fd180 x7 : 0000000000000000 x6 : 000000000080e3ec
[2025-01-07 19:50:13.973] [ 1.308875] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
[2025-01-07 19:50:13.973] [ 1.308886] x2 : 00000000ffff4ddf x1 : ffff800080570080 x0 : 0000000000000001
[2025-01-07 19:50:13.973] [ 1.308901] Kernel panic - not syncing: Asynchronous SError Interrupt
[2025-01-07 19:50:13.973] [ 1.308904] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 6.6.23-lts-next-gd490f49646f0-dirty #1
[2025-01-07 19:50:13.973] [ 1.308909] Hardware name: FSL i.MX8MM EVK board (DT)
[2025-01-07 19:50:13.990] [ 1.308913] Call trace:
[2025-01-07 19:50:13.990] [ 1.308915] dump_backtrace+0x94/0x114
[2025-01-07 19:50:13.990] [ 1.308929] show_stack+0x18/0x24
[2025-01-07 19:50:13.990] [ 1.308940] dump_stack_lvl+0x48/0x60
[2025-01-07 19:50:13.990] [ 1.308955] dump_stack+0x18/0x24
[2025-01-07 19:50:13.990] [ 1.308966] panic+0x31c/0x378
[2025-01-07 19:50:13.990] [ 1.308975] nmi_panic+0x8c/0x90
[2025-01-07 19:50:13.990] [ 1.308984] arm64_serror_panic+0x6c/0x78
[2025-01-07 19:50:13.990] [ 1.308993] do_serror+0x3c/0x70
[2025-01-07 19:50:13.990] [ 1.308998] el1h_64_error_handler+0x30/0x48
[2025-01-07 19:50:13.990] [ 1.309007] el1h_64_error+0x64/0x68
[2025-01-07 19:50:13.990] [ 1.309012] imx_uart_probe+0x3e4/0x980
[2025-01-07 19:50:13.990] [ 1.309021] platform_probe+0x68/0xc4
[2025-01-07 19:50:13.990] [ 1.309035] really_probe+0x188/0x3c4
[2025-01-07 19:50:14.005] [ 1.309044] __driver_probe_device+0x7c/0x16c
[2025-01-07 19:50:14.005] [ 1.309054] driver_probe_device+0x3c/0x110
[2025-01-07 19:50:14.005] [ 1.309066] __driver_attach+0xf0/0x1f8
[2025-01-07 19:50:14.005] [ 1.309077] bus_for_each_dev+0x7c/0xdc
[2025-01-07 19:50:14.005] [ 1.309086] driver_attach+0x24/0x30
[2025-01-07 19:50:14.005] [ 1.309095] bus_add_driver+0x114/0x224
[2025-01-07 19:50:14.005] [ 1.309104] driver_register+0x5c/0x124
[2025-01-07 19:50:14.005] [ 1.309117] __platform_driver_register+0x28/0x34
[2025-01-07 19:50:14.005] [ 1.309130] imx_uart_init+0x54/0x7c
[2025-01-07 19:50:14.005] [ 1.309140] do_one_initcall+0x80/0x1c8
[2025-01-07 19:50:14.010] [ 1.309147] kernel_init_freeable+0x1bc/0x284
[2025-01-07 19:50:14.010] [ 1.309157] kernel_init+0x24/0x1dc
[2025-01-07 19:50:14.010] [ 1.309163] ret_from_fork+0x10/0x20
[2025-01-07 19:50:14.010] [ 1.309172] SMP: stopping secondary CPUs
[2025-01-07 19:50:14.023] [ 1.309180] Kernel Offset: 0x3224c9e00000 from 0xffff800080000000
[2025-01-07 19:50:14.023] [ 1.309183] PHYS_OFFSET: 0xffffdebf00000000
[2025-01-07 19:50:14.023] [ 1.309185] CPU features: 0x0,00000009,00020000,1000421b
[2025-01-07 19:50:14.023] [ 1.309190] Memory Limit: none
[2025-01-07 19:50:14.023] [ 1.561519] ---[ end Kernel panic - not syncing: Asynchronous SError Interrupt ]---

[takeshi100 · Accepted solution]

I made a mistake to fix imx8mm_bl31_setup.c.

■ mistake

    RDC_PDAPn(RDC_PDAP_UART4, D0R | D1W)
■ correct

    RDC_PDAPn(RDC_PDAP_UART4, D0R | D0W),