Re: [PATCH v1] pmdomain: ti_sci: re-sync TIFS with genpd on resume

[Vitor Soares <ivitro@gmail.com>]

Hi Vignesh

Thank you for the review.

On Wed, 2026-04-29 at 10:03 +0530, Vignesh Raghavendra wrote:
> Hi Vitor
> 
> On 27/04/26 13:18, Vitor Soares wrote:
> > From: Vitor Soares <vitor.soares@toradex.com>
> > 
> > When a device in a TI SCI power domain is on the wakeup path of a
> > wakeup-capable child, the suspend path skips genpd_sync_power_off().
> > No put_device is sent to TIFS and the domain's genpd status remains
> > ON.
> 
> Correction of terminologies: TIFS is Root of trust component and is not
> usually involved in power management, that would be DM (Device Manager)
> 

Thank you for the clarification. I will address this on v2. Also, I was thinking
to replace put_device/get_device with ti_sci_pd_power_off/ti_sci_pd_power_on if
that makes more clear the content.

> But to be really sure who is doing what, Could you provide an example
> and the platform on which you see the issue / external abort?
> 

This was reproduced on our Toradex Verdin AM62P WB and the driver for our Wi-Fi
module on the SDIO bus calls device_init_wakeup() during the initialization.

After enter in suspend, it show the following error resume path:


[   41.759341] Internal error: synchronous external abort: 0000000096000010 [#1]
SMP
[   41.843286] CPU: 0 UID: 0 PID: 933 Comm: rtcwake Tainted: G   M       O     
6.18.21-dirty #3 PREEMPT
[   41.852762] Tainted: [M]=MACHINE_CHECK, [O]=OOT_MODULE
[   41.857891] Hardware name: Toradex Verdin AM62P WB on Verdin Development
Board (DT)
[   41.865537] pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[   41.872492] pc : regmap_mmio_read32le+0x8/0x20
[   41.876941] lr : regmap_mmio_read+0x44/0x70
[   41.881120] sp : ffff800081fdb8e0
[   41.884428] x29: ffff800081fdb8e0 x28: 0000000000000000 x27: ffffa95bb64aa9c8
[   41.891563] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
[   41.898697] x23: 0000000080000000 x22: ffff000002df5c00 x21: ffff800081fdb9b4
[   41.905831] x20: 0000000000000100 x19: ffff000001286400 x18: 0000000000000000
[   41.912965] x17: 2d69696d67722f79 x16: 687020726f662067 x15: ffff00007fb74f40
[   41.920100] x14: 00000000000002ea x13: 000000000000031f x12: 0000000000000000
[   41.927234] x11: 00000000000000c0 x10: 00000000000009e0 x9 : ffff800081fdb7a0
[   41.934368] x8 : ffff00007fb6ce00 x7 : 0000000000000000 x6 : 0000000000000000
[   41.941502] x5 : ffffa95bb57948d8 x4 : 0000000000000100 x3 : 0000000000000100
[   41.948636] x2 : ffffa95bb5795034 x1 : 0000000000000100 x0 : ffff80008025d100
[   41.955770] Call trace:
[   41.958211]  regmap_mmio_read32le+0x8/0x20 (P)
[   41.962655]  _regmap_bus_reg_read+0x70/0xb0
[   41.966839]  _regmap_read+0x64/0xdc
[   41.970327]  _regmap_update_bits+0xf4/0x140
[   41.974509]  regmap_update_bits_base+0x64/0x98
[   41.978952]  sdhci_am654_runtime_resume+0x138/0x208
[   41.983830]  pm_generic_runtime_resume+0x2c/0x44
[   41.988445]  __genpd_runtime_resume+0x30/0x7c
[   41.992804]  genpd_runtime_resume+0xdc/0x2e8
[   41.997073]  pm_runtime_force_resume+0x68/0xf4
[   42.001517]  dpm_run_callback+0x8c/0x14c
[   42.005439]  device_resume+0x11c/0x34c
[   42.009188]  dpm_resume+0x178/0x1f0
[   42.012673]  dpm_resume_end+0x18/0x34
[   42.016332]  suspend_devices_and_enter+0x4a4/0x668
[   42.021123]  pm_suspend+0x170/0x2dc
[   42.024610]  state_store+0x80/0x104
[   42.028096]  kobj_attr_store+0x18/0x2c
[   42.031845]  sysfs_kf_write+0x7c/0x94
[   42.035508]  kernfs_fop_write_iter+0x130/0x1fc
[   42.039949]  vfs_write+0x200/0x370
[   42.043351]  ksys_write+0x6c/0x100
[   42.046752]  __arm64_sys_write+0x1c/0x28
[   42.050673]  invoke_syscall.constprop.0+0x50/0xe4
[   42.055378]  do_el0_svc+0x40/0xc4
[   42.058691]  el0_svc+0x40/0x15c
[   42.061834]  el0t_64_sync_handler+0xa0/0xe4
[   42.066015]  el0t_64_sync+0x198/0x19c
[   42.069680] Code: aa0603e0 d65f03c0 f9400000 8b214000 (b9400000)

> 
> > 
> > TIFS powers off the hardware during deep sleep regardless, since it
> > was never informed to keep the domain active. On resume, because the
> > domain's genpd status is ON, no get_device is issued. The driver
> > then accesses registers of a powered-off domain, causing a
> > synchronous external abort (AXI bus error, ESR 0x96000010).
> 
> Hmm, if something is wakeup source, I would expect even TIFS/DM not to
> turn if off, else module wakeup wouldn't work.
> 

I tested UART as a wakeup source and I couldn't reproduce this issue. My
understanding is that UART has its own TI SCI domain and device_may_wakeup() is
true directly on that domain device, so the set_device_constraint fires
correctly and DM keeps it powered.

Here is my tracking of the issue:

Wi-Fi driver registers as wakeup source:
device_init_wakeup(mmc0:0001)

During suspend/resume.
dpm_suspend()
->genpd_suspend_dev(fa20000.mmc)
   ->ti_sci_pd_suspend(fa20000.mmc)
      ->ti_sci_pd_set_wkup_constraint(fa20000.mmc)
        device_may_wakeup(fa20000.mmc)  = false
        set_device_constraint never sent to DM


dpm_suspend_noirq()
->genpd_finish_suspend(fa20000.mmc)
  ->device_awake_path(fa20000.mmc) = true
  ->GENPD_FLAG_ACTIVE_WAKEUP = true
    genpd status = GENPD_STATE_ON
    skip power_off (ti_sci_pd_power_off)

On deep sleep entry, DM powers off fa20000.mmc independently.
It received no set_device_constraint nor ti_sci_pd_power_off.

I attempted to fix this by calling set_device_constraint when 
device_wakeup_path() is true but it prevented the system from entering deep
sleep entirely.

[...]

Best regards,
Vitor Soares