On Fri, 19 Jun 2020 23:03:30 +0100, Cristian Marussi wrote:

When, at probe time, an SCMI communication failure inhibits the capacity to
query power domains states, such domains should be skipped.

Registering partially initialized SCMI Power Domains with GenPD causes a
Kernel panic.

[  292.593774] arm-scmi firmware:scmi: timed out in resp(caller: scmi_power_state_get+0xa4/0xd0)
[  292.602369] scmi-power-domain scmi_dev.2: failed to get state for domain 9
[  292.609366] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[  292.618190] Mem abort info:
[  292.620982]   ESR = 0x96000006
[  292.624065]   EC = 0x25: DABT (current EL), IL = 32 bits
[  292.629403]   SET = 0, FnV = 0
[  292.632474]   EA = 0, S1PTW = 0
[  292.635641] Data abort info:
[  292.638542]   ISV = 0, ISS = 0x00000006
[  292.642396]   CM = 0, WnR = 0
[  292.645364] user pgtable: 4k pages, 48-bit VAs, pgdp=00000009f3691000
[  292.651838] [0000000000000000] pgd=00000009f1ca0003, p4d=00000009f1ca0003, pud=00000009f35ea003, pmd=0000000000000000
[  292.662504] Internal error: Oops: 96000006 [#1] PREEMPT SMP
[  292.672272] CPU: 2 PID: 381 Comm: bash Not tainted 5.8.0-rc1-00011-gebd118c2cca8 #2
[  292.679938] Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Jan  3 2020
   292.662504] Internal error: Oops: 96000006 [#1] PREEMPT SMP
[  292.702221] pstate: 80000005 (Nzcv daif -PAN -UAO BTYPE=--)
[  292.707803] pc : of_genpd_add_provider_onecell+0x98/0x1f8
[  292.713207] lr : of_genpd_add_provider_onecell+0x48/0x1f8
[  292.718609] sp : ffff80001325bb50
[  292.721922] x29: ffff80001325bb50 x28: ffff000974b28ec0
[  292.727240] x27: ffff000971c11380 x26: ffff80001235b200
[  292.732558] x25: ffff00097eff82c0 x24: 0000000000000001
[  292.737874] x23: 00000000ffffffea x22: ffff00097eff82a8
[  292.743191] x21: ffff80001235b1e0 x20: 0000000000000000
[  292.748507] x19: ffff000974b2c080 x18: 0000000000000010
[  292.753823] x17: 0000000000000000 x16: 0000000000000000
[  292.759140] x15: ffffffffffffffff x14: ffff800012139948
[  292.764456] x13: ffff80009325b817 x12: ffff80001325b81f
[  292.769772] x11: ffff80001215a000 x10: 0000000000000a10
[  292.775089] x9 : ffff800010970e08 x8 : ffff000974e84370
[  292.780405] x7 : 00000000ffffffff x6 : ffff00097ef5c1f0
[  292.785721] x5 : ffff00097ef5c1f0 x4 : 0000000000000000
[  292.791038] x3 : ffff80001235b1e0 x2 : fffffffffffffc28
[  292.796354] x1 : 000000000000000a x0 : ffff000971c11680
[  292.801671] Call trace:
[  292.804117]  of_genpd_add_provider_onecell+0x98/0x1f8
[  292.809173]  scmi_pm_domain_probe+0x174/0x1e8
[  292.813533]  scmi_dev_probe+0x90/0xe0
[  292.817198]  really_probe+0xe4/0x448
[  292.820774]  driver_probe_device+0xfc/0x168
[  292.824961]  device_driver_attach+0x7c/0x88
[  292.829146]  bind_store+0xe8/0x128
[  292.832548]  drv_attr_store+0x2c/0x40
[  292.836214]  sysfs_kf_write+0x4c/0x60
[  292.839876]  kernfs_fop_write+0x114/0x230
[  292.843889]  __vfs_write+0x24/0x50
[  292.847291]  vfs_write+0xbc/0x1e0
[  292.850605]  ksys_write+0x70/0xf8
[  292.853919]  __arm64_sys_write+0x24/0x30
[  292.857844]  el0_svc_common.constprop.3+0x94/0x160
[  292.862638]  do_el0_svc+0x2c/0x98
[  292.865954]  el0_sync_handler+0x148/0x1a8
[  292.869964]  el0_sync+0x158/0x180
[  292.873281] Code: eb1a005f d10f6042 540000c1 1400004e (f941ec42)
[  292.879388] ---[ end trace 0077e182f3135393 ]---
[  292.884007] Kernel panic - not syncing: Fatal exception
[  292.889239] SMP: stopping secondary CPUs
[  292.893347] Kernel Offset: 0x140000 from 0xffff800010000000
[  292.898923] PHYS_OFFSET: 0x80000000
[  292.902411] CPU features: 0x240022,25806087
[  292.906594] Memory Limit: none
[  292.909655] ---[ end Kernel panic - not syncing: Fatal exception ]---

[...]

Applied to sudeep.holla/linux (for-next/scmi), thanks!

[1/1] firmware: arm_scmi: Fix SCMI genpd domain probing
      https://git.kernel.org/sudeep.holla/c/e0f1a30cf1

--
Regards,
Sudeep


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