Other Parts Discussed in Thread: AM5728
Tool/software: Linux
I have a custom AM5728 board with a WL1835MOD that I am trying to enable Bluetooth on. I am using a recent Linux 4.14.59 kernel from TI's git repo. When I modprobe st_drv I get the following kernel panic.
[ 41.473886] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 41.482454] pgd = ecb7c000 [ 41.485377] [00000000] *pgd=f70d4835 [ 41.489240] Internal error: Oops: 17 [#1] SMP ARM [ 41.489245] Modules linked in: st_drv(+) cfg80211 [ 41.489268] CPU: 1 PID: 208 Comm: modprobe Not tainted 4.14.59 #2 [ 41.489272] Hardware name: Generic DRA74X (Flattened Device Tree) [ 41.489278] task: ecb2e3c0 task.stack: ecb30000 [ 41.489296] PC is at kim_probe+0x78/0x220 [st_drv] [ 41.489301] LR is at 0xa [ 41.489306] pc : [<bf0cd2e8>] lr : [<0000000a>] psr: 60040013 [ 41.489311] sp : ecb31d58 ip : 00000000 fp : c4ff6c04 [ 41.489315] r10: 00000001 r9 : 00000000 r8 : bf0d039c [ 41.489320] r7 : 00000000 r6 : ee2ef400 r5 : ffffffed r4 : ecad3f00 [ 41.489325] r3 : ecae6400 r2 : bf0ccdcc r1 : bf0ce838 r0 : 00000000 [ 41.489331] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 41.489337] Control: 10c5387d Table: acb7c06a DAC: 00000051 [ 41.489341] Process modprobe (pid: 208, stack limit = 0xecb30218) [ 41.489347] Stack: (0xecb31d58 to 0xecb32000) [ 41.489353] 1d40: c501a5bc bf0d0064 [ 41.489361] 1d60: ee2ef410 ffffffed bf0d0064 fffffdfb bf0d0064 c05970c4 ee2ef410 c501a5bc [ 41.489368] 1d80: c501a5c0 00000000 bf0d0064 c0595324 ee2ef410 bf0d0064 ee2ef444 00000000 [ 41.489376] 1da0: ecb18c70 00000001 c01df538 c05954a4 00000000 bf0d0064 c05953f8 c0593884 [ 41.489384] 1dc0: ee0b20a4 ee2e47d0 bf0d0064 ecb94680 c48a6580 c0594894 bf0ce838 bf0d3000 [ 41.489391] 1de0: ffffe000 bf0d0064 bf0d3000 ffffe000 bf0d0140 c05962cc 00000000 bf0d3000 [ 41.489399] 1e00: ffffe000 c0101df4 60040013 c4807968 ee0000c0 c0192f10 c488b254 c48d009b [ 41.489407] 1e20: 014000c0 c01b1228 ecb95800 c02aa0fc 00000040 c0195994 0000000c c01e2ce4 [ 41.489414] 1e40: ecb95800 bf0d0140 c48d1204 ecb18c40 bf0d0140 c48d1204 ecb95800 bf0d0140 [ 41.489422] 1e60: ecb18c70 c01e3b84 c488b254 c48d1204 c48cfeb3 c48d1204 ecb18c40 c01e2d30 [ 41.489430] 1e80: bf0d014c 00007fff bf0d0140 c01dfdf8 ffffe000 bf0d0188 00000028 c0906400 [ 41.489437] 1ea0: bf0d0280 bf0d02b0 bf0d0294 00000000 bf0ceee4 c02c0001 00000003 00000000 [ 41.489445] 1ec0: c02c5e7c 00000000 00000000 bf0ce024 00000002 00000000 00000000 00000000 [ 41.489452] 1ee0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 41.489460] 1f00: 7fffffff 00000000 00000003 000c5768 0000017b 7fffffff 00000000 00000000 [ 41.489467] 1f20: 000c5bf0 c01e356c 7fffffff 00000000 00000003 ecad2000 c4807968 f1ca6000 [ 41.489475] 1f40: 00007304 00000000 f1ca8eb3 f1ca6000 00007304 f1cacd14 f1cacb8c f1cab370 [ 41.489482] 1f60: 00005000 00005a60 00000000 00000000 00000000 00002914 00000023 00000024 [ 41.489490] 1f80: 0000001a 0000001e 00000016 00000000 000c5768 000c5730 000c5768 c0107ea4 [ 41.489498] 1fa0: ecb30000 c0107ce0 000c5768 000c5730 00000003 000c5768 00000000 000c5788 [ 41.489506] 1fc0: 000c5768 000c5730 000c5768 0000017b 000c5788 00000001 000c5788 000c5bf0 [ 41.489514] 1fe0: beaefb58 beaefb48 00025de8 b6f33a82 80040030 00000003 00000000 00000000 [ 41.489539] [<bf0cd2e8>] (kim_probe [st_drv]) from [<c05970c4>] (platform_drv_probe+0x50/0xac) [ 41.489552] [<c05970c4>] (platform_drv_probe) from [<c0595324>] (driver_probe_device+0x20c/0x2e0) [ 41.489565] [<c0595324>] (driver_probe_device) from [<c05954a4>] (__driver_attach+0xac/0xb0) [ 41.489576] [<c05954a4>] (__driver_attach) from [<c0593884>] (bus_for_each_dev+0x4c/0x9c) [ 41.489587] [<c0593884>] (bus_for_each_dev) from [<c0594894>] (bus_add_driver+0x174/0x208) [ 41.489598] [<c0594894>] (bus_add_driver) from [<c05962cc>] (driver_register+0x78/0xf4) [ 41.489610] [<c05962cc>] (driver_register) from [<c0101df4>] (do_one_initcall+0x3c/0x16c) [ 41.489620] [<c0101df4>] (do_one_initcall) from [<c01e3b84>] (do_init_module+0x5c/0x1e0) [ 41.489627] [<c01e3b84>] (do_init_module) from [<c01e2d30>] (load_module+0x1fc4/0x25d4) [ 41.489635] [<c01e2d30>] (load_module) from [<c01e356c>] (SyS_finit_module+0x98/0xb4) [ 41.489645] [<c01e356c>] (SyS_finit_module) from [<c0107ce0>] (ret_fast_syscall+0x0/0x28) [ 41.489654] Code: 1a00004f e5943094 e59f116c e58340ec (e5970000) [ 41.489662] ---[ end trace b91d7a3d0577d7bb ]---
I instrumented st_kim.c with some debug logging and determined that pdata is unexpectedly null at the start of kim_probe. Here is our relevant DTS.
kim {
compatible = "kim";
nshutdown_gpio = <228>; /* Bank 8, Pin 4 */
dev_name = "/dev/ttyO5";
flow_cntrl = <1>;
baud_rate = <3000000>;
};
A colleague then showed me a related patch TI submitted to the kernel which was merged back in January of 2015.
http://lkml.iu.edu/hypermail/linux/kernel/1501.1/00668.html
Unfortunately, this patch was reverted from the kernel six months later so the device tree binding is being ignored.
http://github.com/torvalds/linux/commit/c0bd1b9e58959c51a4c939505f89721dfbc73c44
Reapplying the patch to TI's 4.14.59 kernel fixed the seg fault. Since loading the btwilink kernel module also loads the broken st_drv kernel module I don't see how Bluetooth can be made to work on the WL1835MOD without this patch. Are there any plans to get a replacement patch upstream? Or should I apply the reverted patch to TI's kernel myself when building?
