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From: Stephen Warren <swarren@wwwdotorg.org>
To: Rob Herring <robherring2@gmail.com>
Cc: Hiroshi Doyu <hdoyu@nvidia.com>,
	linux-arm-kernel@lists.infradead.org,
	Russell King <linux@arm.linux.org.uk>,
	devicetree-discuss@lists.ozlabs.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Rob Herring <rob.herring@calxeda.com>,
	Grant Likely <grant.likely@secretlab.ca>,
	Rob Landley <rob@landley.net>,
	linux-tegra@vger.kernel.org
Subject: Re: [PATCH 4/4] ARM: tegra: Set SCU base address dynamically from DT
Date: Mon, 17 Dec 2012 15:14:02 -0700	[thread overview]
Message-ID: <50CF992A.8080008@wwwdotorg.org> (raw)
In-Reply-To: <50CF258E.2080207@gmail.com>

On 12/17/2012 07:00 AM, Rob Herring wrote:
> On 12/17/2012 12:18 AM, Hiroshi Doyu wrote:
>> Set Snoop Control Unit(SCU) register base address dynamically from DT.

>> diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c

>>  static void __init tegra_smp_init_cpus(void)
>>  {
>> -	unsigned int i, ncores = scu_get_core_count(scu_base);
>> +	struct device_node *np;
>> +	unsigned int i, ncores = 1;
>> +
>> +	np = of_find_matching_node(NULL, cortex_a9_scu_match);
>> +	if (!np)
>> +		return;
>> +	scu_base = of_iomap(np, 0);
> 
> Did you actually test this? Unless something changed, ioremap does not
> work this early. The only reason to have it mapped this early is to get
> the core count, but that doesn't work on A15 or A7. So we really need to
> get core count/mask in a standard way. At least some work to get core
> count from DT went into 3.8.

Does it work if the machine's .map_io() function has set up a static
mapping that includes the specified region? I believe that is the case
on Tegra. What is the alternative if the registers can't be mapped;
should the code count the number of child nodes in /cpus?

  reply	other threads:[~2012-12-17 22:14 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-17  6:18 [PATCH 1/4] ARM: dt: Add doc for ARM Snoop Control Unit(SCU) Hiroshi Doyu
2012-12-17  6:18 ` [PATCH 2/4] ARM: dt: tegra20.dtsi: Add SCU node Hiroshi Doyu
2012-12-17  6:18 ` [PATCH 3/4] ARM: dt: tegra30.dtsi: " Hiroshi Doyu
2012-12-17  6:18 ` [PATCH 4/4] ARM: tegra: Set SCU base address dynamically from DT Hiroshi Doyu
2012-12-17 14:00   ` Rob Herring
2012-12-17 22:14     ` Stephen Warren [this message]
2012-12-18  9:21     ` Hiroshi Doyu
2012-12-18 13:46       ` Rob Herring
2012-12-18 15:15         ` Hiroshi Doyu
2012-12-18 15:32           ` Hiroshi Doyu
2013-01-14 10:43     ` Hiroshi Doyu
2013-01-02 19:02   ` Stephen Warren
2013-01-03  6:38     ` Hiroshi Doyu

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