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From: Tony Lindgren <tony@atomide.com>
To: Paul Walmsley <paul@pwsan.com>
Cc: Rajendra Nayak <rnayak@ti.com>,
	linux-omap@vger.kernel.org, khilman@ti.com, b-cousson@ti.com,
	Nishanth Menon <nm@ti.com>,
	s-sintes@ti.com, Moiz Sonasath <m-sonasath@ti.com>
Subject: Re: [PATCH 7/7] 4460sdp/blaze/panda: hwmod: Prevent gpio1 reset during hwmod init
Date: Tue, 5 Jul 2011 23:47:54 -0700	[thread overview]
Message-ID: <20110706064754.GJ5783@atomide.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1107051534140.4217@utopia.booyaka.com>

* Paul Walmsley <paul@pwsan.com> [110705 14:42]:
> On Tue, 5 Jul 2011, Tony Lindgren wrote:
> > 
> > Can't we always reset the registered hwmods automatically one at a time when
> > omap_device_build is called?
> 
> The experimental series that I wrote, but haven't posted yet, resets each 
> IP block during the first time it's enabled -- which is probably going to 
> be when omap_device_build() is called.

OK
 
> > > That would allow drivers to assume that they are starting from consistent 
> > > device state.  It also should prevent some power management problems 
> > > that are dependent on particular bootloaders.   How about if we add a 
> > > second parameter, hwmod_reset_unused?  The default could be 'no' and then 
> > > only devices with PM runtime-enabled drivers would be reset first.
> > 
> > Yes I think hwmod_reset_unsed would be a better name, but do we actually
> > need any other reset option in addition to that?
> 
> If a driver doesn't reset its device(s) when it starts, then disabling all 
> reset might allow the kernel to boot when the board file is missing some 
> omap_hwmod_no_setup_reset() calls.
> 
> Consider the 4460 GPIO case.  If someone hasn't added in the 
> omap_hwmod_no_setup_reset(gpioX_hwmod) call into the 4460 board file's 
> init_machine(), then these boards would still crash on boot.
> 
> This would definitely be considered a bug in the board file, that it's 
> missing that omap_hwmod_no_setup_reset() call.  But having a general 
> 'hwmod_no_reset' might make it easier during initial board bring-up to 
> determine whether a problem is caused by reset.
> 
> In any case, it doesn't matter too much to me whether a 'hwmod_no_reset' 
> option is preserved or not; this is just based on our discussion of the 
> issue a few months ago.

Yeah. Sounds like for passing the board specific flags for special case
devices is best done with omap2_init_devices() like you suggested.

Tony

  reply	other threads:[~2011-07-06  6:47 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-01  2:07 [PATCH 0/7] OMAP4: Add 4460 base support Rajendra Nayak
2011-07-01  2:07 ` [PATCH 1/7] OMAP: ID: introduce chip detection for OMAP4460 Rajendra Nayak
2011-07-01  2:07   ` [PATCH 2/7] OMAP4: ID: add omap_has_feature for max freq supported Rajendra Nayak
2011-07-01  2:07     ` [PATCH 3/7] OMAP4: PRCM: OMAP4460 specific PRM and CM register bitshifts Rajendra Nayak
2011-07-01  2:07       ` [PATCH 4/7] OMAP4: clocks: Update the clock tree with 4460 clock nodes Rajendra Nayak
2011-07-01  2:07         ` [PATCH 5/7] OMAP4: powerdomain: Reuse on 4460 using CHIP_IS_44XX Rajendra Nayak
2011-07-01  2:08           ` [PATCH 6/7] OMAP4: clockdomain: " Rajendra Nayak
2011-07-01  2:08             ` [PATCH 7/7] 4460sdp/blaze/panda: hwmod: Prevent gpio1 reset during hwmod init Rajendra Nayak
2011-07-01  6:32               ` Tony Lindgren
2011-07-03  4:14                 ` Paul Walmsley
2011-07-04  8:53                   ` Tony Lindgren
2011-07-05  7:40                     ` Paul Walmsley
2011-07-05 10:45                       ` Tony Lindgren
2011-07-05 21:47                         ` Paul Walmsley
2011-07-06  6:47                           ` Tony Lindgren [this message]
2011-07-01  2:41     ` [PATCH 2/7] OMAP4: ID: add omap_has_feature for max freq supported Todd Poynor
2011-07-01  4:48       ` Aneesh V
2011-07-01  6:25   ` [PATCH 1/7] OMAP: ID: introduce chip detection for OMAP4460 Tony Lindgren
2011-07-01 10:15     ` Aneesh V
2011-07-01 16:31 ` [PATCH 0/7] OMAP4: Add 4460 base support Kevin Hilman
2011-07-01 16:36 ` Kevin Hilman
2011-07-01 16:40   ` Kevin Hilman
2011-07-01 17:00     ` Rajendra Nayak

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