Patchwork [v3,3/9] ARM: tegra: Use DT /cpu node to detect number of CPU core

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Submitter Hiroshi Doyu
Date Jan. 15, 2013, 8:13 a.m.
Message ID <1358237598-32413-4-git-send-email-hdoyu@nvidia.com>
Download mbox | patch
Permalink /patch/212011/
State Superseded, archived
Headers show

Comments

Hiroshi Doyu - Jan. 15, 2013, 8:13 a.m.
SCU based detection only works with Cortex-A9 MP and it doesn't
support ones with multiple clusters. The only way to detect number of
CPU core correctly is with DT /cpu node.

Tegra SoCs decided to use DT detection as the only way and to not use
SCU based detection at all. Even if DT /cpu node based detection
fails, it continues with a single core

Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
---
Based on the discussion:
http://lists.infradead.org/pipermail/linux-arm-kernel/2013-January/140608.html

Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
---
 arch/arm/mach-tegra/platsmp.c |   15 ---------------
 1 file changed, 15 deletions(-)
Lorenzo Pieralisi - Jan. 21, 2013, 12:35 p.m.
On Tue, Jan 15, 2013 at 08:13:12AM +0000, Hiroshi Doyu wrote:
> SCU based detection only works with Cortex-A9 MP and it doesn't
> support ones with multiple clusters. The only way to detect number of
> CPU core correctly is with DT /cpu node.
> 
> Tegra SoCs decided to use DT detection as the only way and to not use
> SCU based detection at all. Even if DT /cpu node based detection
> fails, it continues with a single core

Please add missing punctuation, reword the commit log to make it clearer.
> 
> Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
> ---
> Based on the discussion:
> http://lists.infradead.org/pipermail/linux-arm-kernel/2013-January/140608.html
> 
> Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
> ---
>  arch/arm/mach-tegra/platsmp.c |   15 ---------------
>  1 file changed, 15 deletions(-)
> 
> diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c
> index 6867030..689ee4b 100644
> --- a/arch/arm/mach-tegra/platsmp.c
> +++ b/arch/arm/mach-tegra/platsmp.c
> @@ -177,23 +177,8 @@ done:
>  	return status;
>  }
>  
> -/*
> - * Initialise the CPU possible map early - this describes the CPUs
> - * which may be present or become present in the system.
> - */
>  static void __init tegra_smp_init_cpus(void)
>  {
> -	unsigned int i, ncores = scu_get_core_count(scu_base);
> -
> -	if (ncores > nr_cpu_ids) {
> -		pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
> -			ncores, nr_cpu_ids);
> -		ncores = nr_cpu_ids;
> -	}
> -
> -	for (i = 0; i < ncores; i++)
> -		set_cpu_possible(i, true);
> -
>  	set_smp_cross_call(gic_raise_softirq);
>  }
>  

As discussed,

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

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Patch

diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c
index 6867030..689ee4b 100644
--- a/arch/arm/mach-tegra/platsmp.c
+++ b/arch/arm/mach-tegra/platsmp.c
@@ -177,23 +177,8 @@  done:
 	return status;
 }
 
-/*
- * Initialise the CPU possible map early - this describes the CPUs
- * which may be present or become present in the system.
- */
 static void __init tegra_smp_init_cpus(void)
 {
-	unsigned int i, ncores = scu_get_core_count(scu_base);
-
-	if (ncores > nr_cpu_ids) {
-		pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
-			ncores, nr_cpu_ids);
-		ncores = nr_cpu_ids;
-	}
-
-	for (i = 0; i < ncores; i++)
-		set_cpu_possible(i, true);
-
 	set_smp_cross_call(gic_raise_softirq);
 }