ata: sunxi: Regression due to 5253fe05bb47 ("phy: core: Add consumer device link support")

[Corentin Labbe]

Hello

On next-20200108 (at least), the sunxi_ahci fail to probe with:
    3.025955] 8<--- cut here ---
[    3.029012] Unable to handle kernel NULL pointer dereference at virtual address 00000071
[    3.037115] pgd = (ptrval)
[    3.039819] [00000071] *pgd=00000000
[    3.043408] Internal error: Oops: 5 [#1] SMP ARM
[    3.048019] Modules linked in:
[    3.051078] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.5.0-rc1-00004-g5253fe05bb47 #24
[    3.059067] Hardware name: Allwinner sun7i (A20) Family
[    3.064297] PC is at device_link_add+0x68/0x4c8
[    3.068824] LR is at device_link_add+0x68/0x4c8
[    3.073348] pc : [<c04783ac>]    lr : [<c04783ac>]    psr: 60000013
[    3.079605] sp : ef04dd68  ip : 60000013  fp : 00000007
[    3.084822] r10: 00000000  r9 : eea8a740  r8 : ef0a5c10
[    3.090039] r7 : ef0a5c10  r6 : ffffffed  r5 : 00000001  r4 : 00000001
[    3.096556] r3 : ef060000  r2 : 00000000  r1 : 00000000  r0 : c0a4e588
[    3.103076] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[    3.110201] Control: 10c5387d  Table: 4000406a  DAC: 00000051
[    3.115937] Process swapper/0 (pid: 1, stack limit = 0x(ptrval))
[    3.121936] Stack: (0xef04dd68 to 0xef04e000)
[    3.126292] dd60:                   000005e4 c02141e4 ef7bf970 ffffffed ef0a5c10 eea8a7c0
[    3.134461] dd80: 00000000 ef0a5c10 eea8a740 00000000 00000007 c03acaec 00000000 ee8a3700
[    3.142630] dda0: ef7bf970 ee8a3700 ef0a5c10 c04d2804 ef04c000 ef0a5c10 ef0a5c00 ee8a3700
[    3.150799] ddc0: 00000000 00000000 00000000 c04d2e20 00000001 c029b2bc c0a4f9fc 00000000
[    3.158969] dde0: ef0b3630 c029aec8 00000000 5aef773a eea8c478 ef0a5c10 00000000 ef0a5c00
[    3.167138] de00: 00000000 00000000 c0a4f9fc 00000000 00000007 c04cedfc ef0a5c10 00000000
[    3.175307] de20: c0a4f9fc c047d6b8 c0aa51dc ef0a5c10 c0aa51e0 00000000 00000000 c047b894
[    3.183476] de40: ef0a5c10 c0a4f9fc c0a4f9fc c047be38 c093d834 c09004a8 000000d8 c047bb84
[    3.191646] de60: 000000d8 c05a37c0 c0760330 ef0a5c10 00000000 c0a4f9fc c047be38 c093d834
[    3.199815] de80: c09004a8 000000d8 00000007 c047be30 00000000 c0a4f9fc ef0a5c10 c047be90
[    3.207984] dea0: ef0fc634 ef04c000 c0a4f9fc c0479c68 c09004a8 ef01e458 ef0fc634 5aef773a
[    3.216152] dec0: c0a4df18 c0a4f9fc eea8a300 c0a4df18 00000000 c047acb0 c083ac48 c0aa5870
[    3.224321] dee0: c0a4f9fc c0a4f9fc c091eff4 00000000 ffffe000 c047c6fc c0a6fc40 c091eff4
[    3.232491] df00: 00000000 c01026e8 effffe6e c013c488 00000000 c08b9d00 c0845f90 00000000
[    3.240660] df20: 00000006 00000006 c07ff574 00000000 c0809bd8 c07ff5e8 00000000 effffe67
[    3.248829] df40: effffe6a 5aef773a 00000000 00000006 c0a6fc40 5aef773a c093d850 c0952220
[    3.256998] df60: c0a6fc40 c0a6fc40 c093d854 c0900ed0 00000006 00000006 00000000 c09004a8
[    3.265167] df80: 00000000 00000000 c06f7a9c 00000000 00000000 00000000 00000000 00000000
[    3.273335] dfa0: 00000000 c06f7aa4 00000000 c01010e8 00000000 00000000 00000000 00000000
[    3.281504] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[    3.289672] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[    3.297858] [<c04783ac>] (device_link_add) from [<c03acaec>] (devm_of_phy_get+0x64/0xb0)
[    3.305947] [<c03acaec>] (devm_of_phy_get) from [<c04d2804>] (ahci_platform_get_phy+0x28/0xd0)
[    3.314552] [<c04d2804>] (ahci_platform_get_phy) from [<c04d2e20>] (ahci_platform_get_resources+0x234/0x448)
[    3.324372] [<c04d2e20>] (ahci_platform_get_resources) from [<c04cedfc>] (ahci_sunxi_probe+0x10/0xa8)
[    3.333585] [<c04cedfc>] (ahci_sunxi_probe) from [<c047d6b8>] (platform_drv_probe+0x48/0x98)
[    3.342017] [<c047d6b8>] (platform_drv_probe) from [<c047b894>] (really_probe+0x1e0/0x348)
[    3.350267] [<c047b894>] (really_probe) from [<c047bb84>] (driver_probe_device+0x60/0x16c)
[    3.358525] [<c047bb84>] (driver_probe_device) from [<c047be30>] (device_driver_attach+0x58/0x60)
[    3.367390] [<c047be30>] (device_driver_attach) from [<c047be90>] (__driver_attach+0x58/0xcc)
[    3.375908] [<c047be90>] (__driver_attach) from [<c0479c68>] (bus_for_each_dev+0x78/0xb8)
[    3.384080] [<c0479c68>] (bus_for_each_dev) from [<c047acb0>] (bus_add_driver+0x1b4/0x1d4)
[    3.392337] [<c047acb0>] (bus_add_driver) from [<c047c6fc>] (driver_register+0x74/0x108)
[    3.400423] [<c047c6fc>] (driver_register) from [<c01026e8>] (do_one_initcall+0x78/0x1d4)
[    3.408598] [<c01026e8>] (do_one_initcall) from [<c0900ed0>] (kernel_init_freeable+0x138/0x1d4)
[    3.417291] [<c0900ed0>] (kernel_init_freeable) from [<c06f7aa4>] (kernel_init+0x8/0x110)
[    3.425462] [<c06f7aa4>] (kernel_init) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
[    3.433019] Exception stack(0xef04dfb0 to 0xef04dff8)
[    3.438065] dfa0:                                     00000000 00000000 00000000 00000000
[    3.446234] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[    3.454400] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000
[    3.461010] Code: e59f0464 03844040 eb0a0b7b eb004882 (e5d63084) 
[    3.467153] ---[ end trace 0dbbaca7a7b65a4b ]---

The problem was bisected to 5253fe05bb47a2402f471d76078b3dcc66442d6c ("phy: core: Add consumer device link support")
Reverting this patch fix the problem

Regards