From: santosh.shilimkar@ti•com (Santosh Shilimkar)
To: linux-arm-kernel@lists•infradead.org
Subject: [RFC/NOT FOR MERGING 2/3] serial: omap: remove hwmod dependency
Date: Sat, 16 Feb 2013 11:31:21 +0530 [thread overview]
Message-ID: <511F20B1.8010502@ti.com> (raw)
In-Reply-To: <20130215164235.GA20840@arwen.pp.htv.fi>
On Friday 15 February 2013 10:12 PM, Felipe Balbi wrote:
> Hi,
>
> On Fri, Feb 15, 2013 at 08:30:32AM -0800, Tony Lindgren wrote:
>> * Santosh Shilimkar <santosh.shilimkar@ti•com> [130215 05:34]:
>>> On Friday 15 February 2013 06:57 PM, Russell King - ARM Linux wrote:
>>>> On Fri, Feb 15, 2013 at 06:56:47PM +0530, Santosh Shilimkar wrote:
>>>>> Whats your view on use of arch_ioremap_caller() hook ? This can allow
>>>>> us to avoid the dual ioremap() issue discussed here if the hook
>>>>> maintains the list of mapped ios.
>>>>>
>>>>> I was even thinking of having such intelligence within the core
>>>>> ioremap code but thought that might be too invasive.
>>>>
>>>> Why do you even need it? There's no problem with ioremapping the same
>>>> space multiple times (you end up with multiple mappings but that
>>>> shouldn't be a problem, except for the additional space used.)
>>>>
>>> It just waste of iospace and Tony insisted to have just single ioremap()
>>> hence all this discussion
>>
>> The main goal is to avoid duplicating data both in hwmod and DT.
>> That's pretty much solved as we can have the driver probe populate
>> the common data for hwmod from DT as Santosh has already demonstrated.
>>
>> Then we also want the driver specific idle and reset code to be done
>> in the drivers rather than in hwmod and glue it together with hwmod
>> using runtime PM. The biggest issue there is how do we reset and idle
>> some piece of hardware for PM purposes when there's no driver loaded.
>
> right, this will be a tough nut to crack.
>
> I guess the only way would be reset all IPs early in the boot process,
> before even creating the platform-devices. Can we do that ? I mean, from
> omap_device_build_from_dt() we have access to address space of all
> devices, through ti,hwmods we can figure out which hwmods are linked to
> that particular device, so whenever you build a device, you could just
> call _reset().
>
Thats what we do today and it works perfectly. As per Tony's suggestion,
we need to move the non-probed devices reset and idle setup to late_init
which is also doable.
In that case when probed driver calls runtime_get(), we reset that
device and setup the idle settings. And remainder of the devices
are managed in late_init().
> The only problem is that now omap_device_build_from_dt() is called after
> we notify that a new device/driver pair has been registered with the
> platform_bus, right ? So we would still need a way to call _reset() for
> those which are on DTS but don't have a driver bound to them...
>
The only special requirement for reset remains(which today handled by
hwmod function calls) is for devices which needs specific reset
sequence. And this one can be handled through a runtime_reset()
kind of hook.
Does that sound reasonable ?
Regards,
Santosh
next prev parent reply other threads:[~2013-02-16 6:01 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-14 11:15 [RFC/NOT FOR MERGING 1/3] arm: omap: use generic implementation if !od Felipe Balbi
2013-02-14 11:20 ` Russell King - ARM Linux
2013-02-14 17:57 ` Felipe Balbi
[not found] ` <1360840554-26901-2-git-send-email-balbi@ti.com>
2013-02-14 17:12 ` [RFC/NOT FOR MERGING 2/3] serial: omap: remove hwmod dependency Tony Lindgren
2013-02-14 17:56 ` Felipe Balbi
2013-02-14 18:12 ` Tony Lindgren
2013-02-14 19:27 ` Felipe Balbi
2013-02-14 19:39 ` Tony Lindgren
2013-02-14 20:47 ` Paul Walmsley
2013-02-14 21:40 ` Paul Walmsley
2013-02-14 22:47 ` Tony Lindgren
2013-02-15 6:46 ` Felipe Balbi
2013-02-15 7:29 ` Santosh Shilimkar
2013-02-19 15:30 ` Paul Walmsley
2013-02-19 15:45 ` Russell King - ARM Linux
2013-02-19 16:30 ` Tony Lindgren
2013-02-19 18:22 ` Russell King - ARM Linux
2013-02-19 19:31 ` Tony Lindgren
2013-02-19 19:43 ` hwmod data duplication (was: Re: [RFC/NOT FOR MERGING 2/3] serial: omap: remove hwmod dependency) Felipe Balbi
2013-02-19 22:09 ` Tony Lindgren
2013-02-19 22:22 ` Felipe Balbi
2013-02-19 22:31 ` Tony Lindgren
2013-02-19 22:51 ` Felipe Balbi
2013-02-15 10:26 ` [RFC/NOT FOR MERGING 2/3] serial: omap: remove hwmod dependency Russell King - ARM Linux
2013-02-14 21:56 ` Paul Walmsley
2013-02-14 22:22 ` Tony Lindgren
2013-02-15 6:53 ` Felipe Balbi
2013-02-15 7:27 ` Bedia, Vaibhav
2013-02-19 15:27 ` Paul Walmsley
2013-02-19 16:38 ` Tony Lindgren
2013-02-19 16:57 ` Felipe Balbi
2013-02-19 17:43 ` Tony Lindgren
2013-02-19 18:34 ` Felipe Balbi
2013-02-19 19:16 ` Kevin Hilman
2013-02-19 19:32 ` Felipe Balbi
2013-02-19 19:50 ` Kevin Hilman
2013-02-19 20:10 ` OMAP reset requirements (was: Re: [RFC/NOT FOR MERGING 2/3] serial: omap: remove hwmod dependency)^[:x Felipe Balbi
2013-02-19 20:25 ` OMAP reset requirements Kevin Hilman
2013-02-20 6:26 ` [RFC/NOT FOR MERGING 2/3] serial: omap: remove hwmod dependency Santosh Shilimkar
2013-02-15 6:44 ` Felipe Balbi
2013-02-15 7:27 ` Bedia, Vaibhav
2013-02-20 17:38 ` Paul Walmsley
2013-02-20 19:16 ` Felipe Balbi
2013-02-20 20:03 ` Paul Walmsley
2013-02-20 20:37 ` Russell King - ARM Linux
2013-02-21 10:16 ` Peter De Schrijver
2013-02-21 12:09 ` Peter Korsgaard
2013-02-15 10:16 ` Russell King - ARM Linux
2013-02-15 13:26 ` Santosh Shilimkar
2013-02-15 13:27 ` Russell King - ARM Linux
2013-02-15 13:31 ` Santosh Shilimkar
2013-02-15 16:30 ` Tony Lindgren
2013-02-15 16:42 ` Felipe Balbi
2013-02-16 6:01 ` Santosh Shilimkar [this message]
2013-02-16 8:55 ` Felipe Balbi
2013-02-16 9:17 ` Santosh Shilimkar
2013-02-16 9:22 ` Felipe Balbi
2013-02-16 9:31 ` Santosh Shilimkar
2013-02-18 15:27 ` Kevin Hilman
2013-02-16 5:31 ` Santosh Shilimkar
2013-02-16 5:36 ` Nicolas Pitre
2013-02-16 5:48 ` Santosh Shilimkar
2013-02-18 8:08 ` Bedia, Vaibhav
2013-02-18 8:28 ` Santosh Shilimkar
2013-02-15 15:40 ` Kevin Hilman
2013-02-15 16:03 ` Felipe Balbi
2013-02-16 4:59 ` Santosh Shilimkar
2013-02-18 14:52 ` Kevin Hilman
2013-02-15 15:28 ` [RFC/NOT FOR MERGING 1/3] arm: omap: use generic implementation if !od Kevin Hilman
2013-02-15 16:04 ` Felipe Balbi
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