Re: Sierra Wireless EM9191 integration issues in mhi+wwan

[Aleksander Morgado <aleksander@aleksander.es>]

Hey,

> > The successful boots seem to happen always on cold boots, and the
> > success rate is low (30% or so) on some manual testing here. I haven't
> > seen one single successful boot on system restarts, they all fail like
> > in the previous email.
> >
> > When the boot is successful it looks like this:
> >
>
> This looks to be a firmware issue. The device is in SYS_ERR state during
> boot and that's expected. But what is strange is that the device stays
> in SYS_ERR even after host issues RESET.
>
> Can you try the below diff and see if it does any good?
>
> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> index fb99e3727155..a43c3ed77fb1 100644
> --- a/drivers/bus/mhi/core/pm.c
> +++ b/drivers/bus/mhi/core/pm.c
> @@ -104,7 +104,8 @@ static struct mhi_pm_transitions const dev_state_transitions[] = {
>         /* L3 States */
>         {
>                 MHI_PM_LD_ERR_FATAL_DETECT,
> -               MHI_PM_LD_ERR_FATAL_DETECT | MHI_PM_DISABLE
> +               MHI_PM_LD_ERR_FATAL_DETECT | MHI_PM_DISABLE |
> +               MHI_PM_SYS_ERR_PROCESS
>         },
>  };

Tested again in the RPi CM4 based setup, but didn't help, it's failing
in the same way, still says PASS THROUGH state: SYS ERROR:

[    7.032037] mhi-pci-generic 0000:01:00.0: MHI PCI device found: sierra-em919x
[    7.039213] mhi-pci-generic 0000:01:00.0: BAR 0: assigned [mem
0x600000000-0x600000fff 64bit]
[    7.047759] mhi-pci-generic 0000:01:00.0: enabling device (0000 -> 0002)
[    7.054573] mhi-pci-generic 0000:01:00.0: using shared MSI
[    7.060848] mhi mhi0: Requested to power ON
[    7.065277] mhi mhi0: Attempting power on with EE: PASS THROUGH,
state: SYS ERROR
[    7.072799] mhi mhi0: local ee: INVALID_EE state: RESET device ee:
PASS THROUGH state: SYS ERROR
[    7.081589] mhi mhi0: System error detected
[    7.085867] mhi-pci-generic 0000:01:00.0: firmware crashed (7)
[    7.091886] mhi mhi0: Handling state transition: SYS ERROR
[    7.097399] mhi mhi0: Transitioning from PM state: SYS ERROR Detect
to: SYS ERROR Process
[    7.105588] mhi-pci-generic 0000:01:00.0: firmware crashed (6)

I've tested the same patches in my desktop PC (based on 5.13.1, and
even without this last addition) and the boot process is much more
stable and I cannot see the "firmware crashed" errors reported. My
assumption right now is that the pci_generic.c entries we're adding
are correct, but there's some limitation in this system that is making
the EM9191 boot fail, but I still don't know which limitation it is.
The memory addresses in the "BAR 0: assigned" log are definitely
different in the RPi CM4, and also the shared MSI limitation. I recall
Thomas saying that he also tested on a desktop PC forcing the shared
MSI limitation and he had the same kind of firmware errors reported;
I'll also try to test that.

Here are the logs in my desktop pc for reference:
oct 21 09:24:06 ares kernel: mhi-pci-generic 0000:17:00.0: MHI PCI
device found: sierra-em919x
oct 21 09:24:06 ares kernel: mhi-pci-generic 0000:17:00.0: BAR 0:
assigned [mem 0xb5e01000-0xb5e01fff 64bit]
oct 21 09:24:06 ares kernel: mhi mhi0: Requested to power ON
oct 21 09:24:06 ares kernel: mhi mhi0: Power on setup success
oct 21 09:24:06 ares kernel: mhi mhi0: Handling state transition: READY
oct 21 09:24:06 ares kernel: mhi mhi0: Device in READY State
oct 21 09:24:06 ares kernel: mhi mhi0: Initializing MHI registers
oct 21 09:24:06 ares kernel: mhi mhi0: State change event to state: M0
oct 21 09:24:06 ares kernel: mhi mhi0: Received EE event: MISSION MODE
oct 21 09:24:06 ares kernel: mhi mhi0: Handling state transition: MISSION MODE
oct 21 09:24:06 ares kernel: mhi mhi0: Processing Mission Mode transition
oct 21 09:24:06 ares kernel: mhi_net mhi0_IP_HW0: 100: Updating
channel state to: START
oct 21 09:24:06 ares kernel: mhi_net mhi0_IP_HW0: 100: Channel state
change to START successful
oct 21 09:24:06 ares kernel: mhi_net mhi0_IP_HW0: 101: Updating
channel state to: START
oct 21 09:24:06 ares kernel: mhi_net mhi0_IP_HW0: 101: Channel state
change to START successful
oct 21 09:24:08 ares kernel: mhi mhi0: Allowing M3 transition
oct 21 09:24:08 ares kernel: mhi mhi0: Waiting for M3 completion
oct 21 09:24:08 ares kernel: mhi mhi0: State change event to state: M3

-- 
Aleksander
https://aleksander.es