Hi Dan,

On Fri, 17 Jul 2020 at 14:31, Anand Moon [off-list ref] wrote:

Hi Dan,

On Wed, 15 Jul 2020 at 21:53, Anand Moon [off-list ref] wrote:

quoted

Hi Dan,

On Wed, 15 Jul 2020 at 08:48, Dan Robertson [off-list ref] wrote:

quoted

On Tue, Jul 14, 2020 at 08:57:35PM +0530, Anand Moon wrote:

quoted

Hi Dan,

On Tue, 14 Jul 2020 at 19:00, Dan Robertson [off-list ref] wrote:

quoted

Hi Anand!

On Tue, Jul 14, 2020 at 12:26:57PM +0530, Anand Moon wrote:

quoted

hi Dan,

On Mon, 13 Jul 2020 at 21:37, Dan Robertson [off-list ref] wrote:

quoted

When testing suspend for another driver I noticed the following warning:

WARNING: CPU: 1 PID: 5530 at drivers/reset/core.c:355 reset_control_assert+0x184/0x19c
Hardware name: Hardkernel ODROID-N2 (DT)
[..]
pc : reset_control_assert+0x184/0x19c
lr : dwc3_meson_g12a_suspend+0x68/0x7c
[..]
Call trace:
 reset_control_assert+0x184/0x19c
 dwc3_meson_g12a_suspend+0x68/0x7c
 platform_pm_suspend+0x28/0x54
 __device_suspend+0x590/0xabc
 dpm_suspend+0x104/0x404
 dpm_suspend_start+0x84/0x1bc
 suspend_devices_and_enter+0xc4/0x4fc

In my limited experience and knowlege it appears that we hit this
because the reset control was switched to shared and the the use
of the reset control was not changed.

quoted

* Calling reset_control_assert without first calling reset_control_deassert
* is not allowed on a shared reset control. Calling reset_control_reset is
* also not allowed on a shared reset control.

The above snippet from reset_control_get_shared() seems to indicate that
this is due to the use of reset_control_reset() in dwc3_meson_g12a_probe()
and reset_control_deassert is not guaranteed to have been called
before dwc3_meson_g12a_suspend() and reset_control_assert().

After some basic tests with the following patch I no longer hit the
warning. Comments and critiques on the patch are welcome. If there is a
reason for the current use of the reset control, I'd love to learn why!
Like I said before, I have not really looked at this driver before and
have verify limited experience with reset controls... Was working on
another driver, hit the warning, and thought I'd take a shot at the
fix :-)

Thanks, I was also looking into this issue

Awesome!

quoted

So best Fix to this issue is to drop the call of reset_control_assert
from dwc3_meson_g12a_suspend
and drop the call of reset_control_deassert from dwc3_meson_g12a_resume
With these changes we do not see the warning on suspend and resume

We definitely would avoid hitting the warning without the
reset_control_(de)assert calls in suspend and resume. That is a valid use of
the reset control, but why would that be best?

From reset_control_reset():

Before entering the suspend state the code tries to do following
     clk_bulk_disable_unprepare
     regulator_disable
     phy_power_off
     phy_exit

After this operation it's needless to call *reset_control_assert*
I tried to move this call before all the above operations
but still no success with this.

How so? Once the reset() is removed prope() and deassert() is guaranteed
to have been called before suspend, like what is in the patch and similar
to other uses of shared reset controllers, this is possible.

quoted

Similarly on resume we should avoid calling resume
*reset_control_deassert* earlier
as the core is just reinitializing the devices.
      clk_bulk_prepare_enable
      usb_init
      phy_init
      phy_power_on
      regulator_enable

quoted

quoted

* Consumers must not use reset_control_(de)assert on shared reset lines when
* reset_control_reset has been used.

If we use reset_control_reset() then we can not (de)assert the reset line
on suspend/resume or any other time. Wouldn't we want to be able to
(de)assert the reset line? And why do we no longer want to (de)assert the
reset line on suspend/resume?

quoted

quoted

Can you try this attached patch?

I think I had already tested something similar. Removing the (de)assert calls
but keeping reset will definitely remove the warning, but it means we can not
(de)assert the line. My guess is that this is not what we want, but I could be
wrong. Thoughts, input, or references to documentation on this would be
appreciated.

As per my knowledge suspend to mem will do complete power down of the
devices with support suspend and resume feature sequentially and then it tries
to bring the device up one by one.
So it should also take care of reset lines as well.

So do we only _actually_ care about the reset line in the probe? Seems like we
should remove the reset controller from the structure if that is the case.

Cheers,

 - Dan

Sorry I am not the _expert_ in suspend/resume feature but I can debug this,
Certainly we need to look into whether reset controller calls are needed
to suspend or resume for this driver.

First thing we need to get the RTC driver to work on Odroid N2 for
suspend wakeup
to work properly.
For this I have created the following patches.

[0] https://patchwork.kernel.org/cover/11665865/

With these patches the RTC feature for wake up is broken right now in
my testing.
Once I get something to work further I will update you.

--Anand

Sorry for the _noise_ :‑(
This feature seems to be working fine with VRTC drivers.
I have tested this with a pre-compiled image of Archlinux distro.

[root@alarm alarm]# uname -a
Linux alarm 5.7.8-1-ARCH #1 SMP Sun Jul 12 03:38:28 UTC 2020 aarch64 GNU/Linux
[root@alarm alarm]# rtcwake -s 30 -m mem
rtcwake: assuming RTC uses UTC ...
rtcwake: wakeup from "mem" using /dev/rtc0 at Thu Jan  1 00:10:14 1970
[  583.591477] PM: suspend entry (deep)
[  583.593737] Filesystems sync: 0.002 seconds
[  583.818967] Freezing user space processes ... (elapsed 0.005 seconds) done.
[  583.825802] OOM killer disabled.
[  583.828966] Freezing remaining freezable tasks ... (elapsed 0.003
seconds) done.
[  583.880280] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[  584.020094] PM: suspend devices took 0.190 seconds
[  584.070586] Disabling non-boot CPUs ...
[  584.075037] CPU1: shutdown
[  584.075223] psci: CPU1 killed (polled 0 ms)
[  584.097199] CPU2: shutdown
[  584.098546] psci: CPU2 killed (polled 0 ms)
[  584.115370] CPU3: shutdown
[  584.116500] psci: CPU3 killed (polled 0 ms)
[  584.128116] CPU4: shutdown
[  584.129235] psci: CPU4 killed (polled 10 ms)
[  584.140122] CPU5: shutdown
[  584.147289] psci: CPU5 killed (polled 0 ms)
bl30 get wakeup sources!
process command 00000006
bl30 enter suspend!
Little core clk suspend rate 1896000000
Big core clk suspend rate 24000000
store restore gp0 pll
suspend_counter: 3
Enter ddr suspend
ddr suspend time: 16us
alarm=31S
process command 00000001
GPIOA_11/13 off
cec ver:2018/04/19
CEC cfg:0x0000
WAKEUP GPIO cfg:0x00000000
use vddee new table!
use vddee new table!
exit_reason:0x03
Enter ddr resume
DMC_DRAM_STAT3: 0x544
ddr resume time: 3188us
store restore gp0 pll
cfg15 33b00000
cfg15 33b00000
Li[  584.148720] Enabling non-boot CPUs ...
[  584.149124] Detected VIPT I-cache on CPU1
[  584.149167] CPU1: Booted secondary processor 0x0000000001 [0x410fd034]
[  584.149594] CPU1 is up
[  584.160687] Detected VIPT I-cache on CPU2
[  584.160730] arch_timer: CPU2: Trapping CNTVCT access
[  584.160741] CPU2: Booted secondary processor 0x0000000100 [0x410fd092]
[  584.161327] CPU2 is up
[  584.177645] Detected VIPT I-cache on CPU3
[  584.177668] arch_timer: CPU3: Trapping CNTVCT access
[  584.177675] CPU3: Booted secondary processor 0x0000000101 [0x410fd092]
[  584.178036] CPU3 is up
[  584.195338] Detected VIPT I-cache on CPU4
[  584.195361] arch_timer: CPU4: Trapping CNTVCT access
[  584.195368] CPU4: Booted secondary processor 0x0000000102 [0x410fd092]
[  584.195762] CPU4 is up
[  584.213002] Detected VIPT I-cache on CPU5
[  584.213024] arch_timer: CPU5: Trapping CNTVCT access
[  584.213032] CPU5: Booted secondary processor 0x0000000103 [0x410fd092]
[  584.213450] CPU5 is up
ttle core clk resume rate 1896000000
Big core clk resume rate 50000000
[  584.279042] meson8b-dwmac ff3f0000.ethernet eth0: No Safety
Features support found
[  584.281232] meson8b-dwmac ff3f0000.ethernet eth0: configuring for
phy/rgmii link mode
[  584.401216] usb usb1: root hub lost power or was reset
[  584.401470] usb usb2: root hub lost power or was reset
[  584.655446] dwc3-meson-g12a ffe09000.usb: switching to Device Mode
[  584.801108] usb 2-1: reset SuperSpeed Gen 1 USB device number 2
using xhci-hcd
[  584.979632] usb 1-1: reset high-speed USB device number 2 using xhci-hcd
[  585.260450] usb 2-1.1: reset SuperSpeed Gen 1 USB device number 3
using xhci-hcd
[  585.333303] PM: resume devices took 1.100 seconds
[  585.333507] OOM killer enabled.
[  585.335549] Restarting tasks ... done.
[  585.378044] PM: suspend exit
rtcwake: read rtc alarm failed: Invalid argument
[root@alarm alarm]#

-Anand

After confirming that the suspend resume feature is working correctly
I found the solution to the reset warning on 5.8.x kernel
Please can you try this following patch.

$ cat resetwarn.patch

diff --git a/drivers/usb/dwc3/dwc3-meson-g12a.c

b/drivers/usb/dwc3/dwc3-meson-g12a.c
index 1f7f4d88ed9d..60a6f49139fd 100644

--- a/drivers/usb/dwc3/dwc3-meson-g12a.c
+++ b/drivers/usb/dwc3/dwc3-meson-g12a.c

@@ -730,7 +730,7 @@ static int dwc3_meson_g12a_probe(struct

platform_device *pdev)

        platform_set_drvdata(pdev, priv);

-       priv->reset = devm_reset_control_get_shared(dev, NULL);
+       priv->reset = devm_reset_control_get_shared(dev, "dwc3_meson");
        if (IS_ERR(priv->reset)) {
                ret = PTR_ERR(priv->reset);
                dev_err(dev, "failed to get device reset, err=%d\n", ret);

-Anand

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