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From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: SPEAr600: Add device-tree support to SPEAr600 boards
Date: Tue, 27 Mar 2012 11:59:35 +0000	[thread overview]
Message-ID: <201203271159.35306.arnd@arndb.de> (raw)
In-Reply-To: <4F71A42C.3090108@st.com>

On Tuesday 27 March 2012, Viresh Kumar wrote:
> On 3/27/2012 4:45 PM, Arnd Bergmann wrote:
> > On Tuesday 27 March 2012, Viresh Kumar wrote:
> > The normal way is to turn around the logic so you don't have to include this test
> > at all. Just have one soc-specific init_machine and map_io function, that calls
> > both soc-specific and shared soc functions, e.g.
> 
> But with that, i need multiple DT_MACHINE_START(). Isn't it?
> Is this advisable?

Having one DT_MACHINE_START per soc is ok if it helps you. Of course if you
have multiple ones that are basically identical, it's simpler to just
combine them.

> > In case of the clocks, I think you could already merge all the clk_lookup
> > arrays into one, which would result in a larger kernel image but should
> > do no harm otherwise.
> 
> Actually we can't do it. :(
> If i boot 300 then i will also get clocks of 310 and 320 in my clock list.
> And once i go through this clock list to create clock tree (parent-child
> relationship), i will try to access hardware registers of 310 & 320,
> which are just not valid for 300. Kernel Crash!!

Ok, I see. BTW, have you tried what I first recommended to you, which is
to check the compatible property of the clock node instead of the machine?

Obviously that only works when you initialize the clocks from init_early()
instead of from map_io(), but I think that would be the cleanest choice
if you want to have single function with run-time dependencies.

	Arnd

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
To: Viresh Kumar <viresh.kumar-qxv4g6HH51o@public.gmane.org>
Cc: spear-devel <spear-devel-nkJGhpqTU55BDgjK7y7TUQ@public.gmane.org>,
	Stefan Roese <sr-ynQEQJNshbs@public.gmane.org>,
	viresh kumar
	<viresh.linux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
	"devicetree-discuss-mnsaURCQ41sdnm+yROfE0A@public.gmane.org"
	<devicetree-discuss-mnsaURCQ41sdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH] ARM: SPEAr600: Add device-tree support to SPEAr600 boards
Date: Tue, 27 Mar 2012 11:59:35 +0000	[thread overview]
Message-ID: <201203271159.35306.arnd@arndb.de> (raw)
In-Reply-To: <4F71A42C.3090108-qxv4g6HH51o@public.gmane.org>

On Tuesday 27 March 2012, Viresh Kumar wrote:
> On 3/27/2012 4:45 PM, Arnd Bergmann wrote:
> > On Tuesday 27 March 2012, Viresh Kumar wrote:
> > The normal way is to turn around the logic so you don't have to include this test
> > at all. Just have one soc-specific init_machine and map_io function, that calls
> > both soc-specific and shared soc functions, e.g.
> 
> But with that, i need multiple DT_MACHINE_START(). Isn't it?
> Is this advisable?

Having one DT_MACHINE_START per soc is ok if it helps you. Of course if you
have multiple ones that are basically identical, it's simpler to just
combine them.

> > In case of the clocks, I think you could already merge all the clk_lookup
> > arrays into one, which would result in a larger kernel image but should
> > do no harm otherwise.
> 
> Actually we can't do it. :(
> If i boot 300 then i will also get clocks of 310 and 320 in my clock list.
> And once i go through this clock list to create clock tree (parent-child
> relationship), i will try to access hardware registers of 310 & 320,
> which are just not valid for 300. Kernel Crash!!

Ok, I see. BTW, have you tried what I first recommended to you, which is
to check the compatible property of the clock node instead of the machine?

Obviously that only works when you initialize the clocks from init_early()
instead of from map_io(), but I think that would be the cleanest choice
if you want to have single function with run-time dependencies.

	Arnd

  parent reply	other threads:[~2012-03-27 11:59 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-13 14:47 [PATCH] ARM: SPEAr600: Add device-tree support to SPEAr600 boards Stefan Roese
2012-03-13 14:47 ` Stefan Roese
2012-03-13 16:44 ` Arnd Bergmann
2012-03-13 16:44   ` Arnd Bergmann
2012-03-14  7:08   ` Viresh Kumar
2012-03-14  7:08     ` Viresh Kumar
2012-03-14  9:58     ` Arnd Bergmann
2012-03-14  9:58       ` Arnd Bergmann
2012-03-14 10:02       ` Viresh Kumar
2012-03-14 10:02         ` Viresh Kumar
2012-03-14  7:40   ` Stefan Roese
2012-03-14  7:40     ` Stefan Roese
2012-03-14  9:48     ` Arnd Bergmann
2012-03-14  9:48       ` Arnd Bergmann
2012-03-14 10:36       ` Stefan Roese
2012-03-14 10:36         ` Stefan Roese
2012-03-14 13:27         ` Arnd Bergmann
2012-03-14 13:27           ` Arnd Bergmann
2012-03-14 13:43           ` Stefan Roese
2012-03-14 13:43             ` Stefan Roese
2012-03-14 14:09             ` Arnd Bergmann
2012-03-14 14:09               ` Arnd Bergmann
2012-03-14 13:44           ` Rob Herring
2012-03-14 13:44             ` Rob Herring
2012-03-14  7:05 ` Viresh Kumar
2012-03-14  7:05   ` Viresh Kumar
2012-03-14  7:20   ` Stefan Roese
2012-03-14  7:20     ` Stefan Roese
2012-03-15  8:48   ` Stefan Roese
2012-03-15  8:48     ` Stefan Roese
2012-03-15  9:00     ` Viresh Kumar
2012-03-15  9:00       ` Viresh Kumar
2012-03-15 10:38       ` Stefan Roese
2012-03-15 10:38         ` Stefan Roese
2012-03-15 10:40         ` Viresh Kumar
2012-03-15 10:40           ` Viresh Kumar
2012-03-15 13:39         ` Arnd Bergmann
2012-03-15 13:39           ` Arnd Bergmann
2012-03-21 11:32           ` Viresh Kumar
2012-03-21 11:32             ` Viresh Kumar
2012-03-21 12:36             ` Arnd Bergmann
2012-03-21 12:36               ` Arnd Bergmann
2012-03-21 13:28               ` viresh kumar
2012-03-21 13:28                 ` viresh kumar
2012-03-21 14:04                 ` Arnd Bergmann
2012-03-21 14:04                   ` Arnd Bergmann
2012-03-21 14:18                   ` viresh kumar
2012-03-21 14:18                     ` viresh kumar
2012-03-21 14:42                     ` Arnd Bergmann
2012-03-21 14:42                       ` Arnd Bergmann
2012-03-21 18:26                   ` Arnd Bergmann
2012-03-21 18:26                     ` Arnd Bergmann
2012-03-22  0:45                     ` viresh kumar
2012-03-22  0:45                       ` viresh kumar
2012-03-22  8:10                       ` Arnd Bergmann
2012-03-22  8:10                         ` Arnd Bergmann
     [not found]                         ` <201203220810.00628.arnd-r2nGTMty4D4@public.gmane.org>
2012-03-22  8:51                           ` viresh kumar
     [not found]               ` <201203211236.37891.arnd-r2nGTMty4D4@public.gmane.org>
2012-03-22 13:46                 ` viresh kumar
2012-03-22 14:20                   ` Arnd Bergmann
2012-03-22 14:20                     ` Arnd Bergmann
     [not found]                     ` <201203221420.10127.arnd-r2nGTMty4D4@public.gmane.org>
2012-03-22 14:53                       ` viresh kumar
2012-03-27 10:27                     ` Viresh Kumar
2012-03-27 10:27                       ` Viresh Kumar
2012-03-27 11:15                       ` Arnd Bergmann
2012-03-27 11:15                         ` Arnd Bergmann
2012-03-27 11:27                         ` Viresh Kumar
2012-03-27 11:27                           ` Viresh Kumar
2012-03-27 11:45                           ` Viresh Kumar
2012-03-27 11:45                             ` Viresh Kumar
2012-03-27 11:59                           ` Arnd Bergmann [this message]
2012-03-27 11:59                             ` Arnd Bergmann
     [not found]                             ` <201203271159.35306.arnd-r2nGTMty4D4@public.gmane.org>
2012-03-27 13:44                               ` viresh kumar
2012-03-27 13:59                                 ` Arnd Bergmann
2012-03-27 13:59                                   ` Arnd Bergmann
2012-03-28  5:03                                   ` Viresh Kumar
2012-03-28  5:03                                     ` Viresh Kumar
2012-03-28  8:13                                     ` Arnd Bergmann
2012-03-28  8:13                                       ` Arnd Bergmann
2012-03-14  8:48 ` Jean-Christophe PLAGNIOL-VILLARD
2012-03-14  8:48   ` Jean-Christophe PLAGNIOL-VILLARD

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