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

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Date:	Tue, 9 Feb 2016 21:34:32 +0000 (UTC)
From:	Paul Walmsley <paul@...an.com>
To:	Dave Gerlach <d-gerlach@...com>
cc:	Suman Anna <s-anna@...com>, Kishon Vijay Abraham I <kishon@...com>,
	Tony Lindgren <tony@...mide.com>, bhelgaas@...gle.com,
	richardcochran@...il.com, 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

On Tue, 9 Feb 2016, Dave Gerlach wrote:

> 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.

The patches that Kishon posted shouldn't change the existing hardreset 
behavior for any IP block with HWMOD_CUSTOM_HARDRESET marked.  If the
behavior changes before and after that patch set, something isn't right.

> 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).

I no longer recall why we had the _are_all_hardreset_lines_asserted(oh) 
test in place.  But we might be able to drop it now that we have the 
HWMOD_CUSTOM_HARDRESET flag.
 

- Paul