linux-kernel - Re: [PATCH 0/3] omap: hwmod: add default reset handling support

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Message-ID: <56BA49D4.8040900@ti.com>
Date:	Tue, 9 Feb 2016 14:19:32 -0600
From:	Dave Gerlach <d-gerlach@...com>
To:	Suman Anna <s-anna@...com>, Kishon Vijay Abraham I <kishon@...com>,
	Paul Walmsley <paul@...an.com>,
	Tony Lindgren <tony@...mide.com>, <bhelgaas@...gle.com>,
	<richardcochran@...il.com>
CC:	Russell King <linux@....linux.org.uk>,
	<linux-omap@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <bcousson@...libre.com>,
	<nsekhar@...com>
Subject: Re: [PATCH 0/3] omap: hwmod: add default reset handling support

Hi,
On 02/09/2016 11:44 AM, Suman Anna wrote:
> On 02/08/2016 11:17 PM, Kishon Vijay Abraham I wrote:
>> Hi,
>>
>> On Tuesday 09 February 2016 02:37 AM, Suman Anna wrote:
>>> On 02/08/2016 05:12 AM, Kishon Vijay Abraham I wrote:
>>>> Add a new hwmod flag to indicate custom reset handling and use it
>>>> for devices that require custom reset handling (like dsp, ipu, iva).
>>>>
>>>> Tested PCIe on dra7-evm and dra72-evm.
>>>> I need help in testing DSP, IPU, IVA, PRU, GFX, M3 in other platforms.
>>>> Or a way to test these cores to see if reset is not broken. Suman?
>>>
>>> I won't be able to test this week, and have requested Dave to check on
>>> wkup_m3_rproc driver atleast. I see one potential issue (see my commment
>>> on the other thread), but can confirm that only after testing.
>>>
>>> Have you tested multiple probe/removal sequences? Can you check the
>>> return status on the _hardreset_deassert call with your PCIe driver,
>>> believe even that one would return an error on multiple probes.
>>
>> hmm.. the PCIe driver is built-in and can't be made as module because of other
>> issues in PCIe core. But looks like the first deassert succeeded since I didn't
>> observe the boot hang because of PCIe.
>
> You can try unbind and bind through sysfs, it should result in a remove
> and probe even if your driver is built-in.

Sorry got held up by the discussion here [1], that regression affects 
rmmod/re-insmod of wkup_m3_rproc as well. If I revert the guilty patch 
5de85b9d57ab ("PM / runtime: Re-init runtime
PM states at probe error and driver unbind") and apply these three 
patches, on initial probe of the wkup_m3_rproc and wkup_m3_ipc drivers 
in v4.5-rc3 I see:

[   15.593460] omap_hwmod: wkup_m3: _wait_target_disable failed

Which is triggered by the reset of the wkup_m3 from the wkup_m3_ipc 
driver when booting the wkup_m3_rproc. Flow is:

1. wkup_m3_rproc probes and calls pm_runtime_get_sync, which calls hwmod 
_enable but bails out because _are_all_hardreset_lines_asserted(oh) 
causes it to return 0.

2. wkup_m3_ipc probes and calls rproc_boot, which triggers 
omap_device_deassert_hardreset in order to let the wkup_m3 start.

It is inside the omap_device_deassert_hardreset ( and inside that, 
omap_hwmod_deassert_hardreset) where I end up with the error message, 
but after that rmmod/insmod of the module over and over again shows no 
additional error messages (at least with the above mentioned PM patch 
reverted).

Regards,
Dave

[1] http://www.spinics.net/lists/arm-kernel/msg477160.html

>
> regards
> Suman
>>>
>>>>
>>>> I'll post this series once again after performing these tests.
>>>>
>>>> Paul Walmsley (3):
>>>>    ARM: omap2+: omap_hwmod: introduce hwmod flag for custom reset
>>>>      handling
>>>>    ARM: OMAP2+: hwmod: use HWMOD_CUSTOM_HARDRESET for custom reset
>>>>      handling
>>>>    ARM: OMAP2+: hwmod: Add default reset handling
>>>>
>>>>   arch/arm/mach-omap2/omap_hwmod.c                   |   16 +++++++++++-----
>>>>   arch/arm/mach-omap2/omap_hwmod.h                   |   12 ++++++++++++
>>>>   arch/arm/mach-omap2/omap_hwmod_2420_data.c         |    2 ++
>>>>   arch/arm/mach-omap2/omap_hwmod_2430_data.c         |    1 +
>>>>   .../mach-omap2/omap_hwmod_33xx_43xx_ipblock_data.c |    2 ++
>>>>   arch/arm/mach-omap2/omap_hwmod_33xx_data.c         |    1 +
>>>>   arch/arm/mach-omap2/omap_hwmod_3xxx_data.c         |    3 +++
>>>>   arch/arm/mach-omap2/omap_hwmod_43xx_data.c         |    1 +
>>>>   arch/arm/mach-omap2/omap_hwmod_44xx_data.c         |    6 ++++++
>>>>   arch/arm/mach-omap2/omap_hwmod_54xx_data.c         |    2 ++
>>>>   10 files changed, 41 insertions(+), 5 deletions(-)
>>>>
>>>
>