linux-kernel - [PATCH] msm: platsmp: actually read core count in get_core

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Message-Id: <1302223269-32047-1-git-send-email-johlstei@codeaurora.org>
Date:	Thu,  7 Apr 2011 17:41:09 -0700
From:	Jeff Ohlstein <johlstei@...eaurora.org>
To:	Daniel Walker <dwalker@...o99.com>,
	Bryan Huntsman <bryanh@...eaurora.org>,
	David Brown <davidb@...eaurora.org>
Cc:	linux-arm-msm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Jeff Ohlstein <johlstei@...eaurora.org>,
	Russell King <linux@....linux.org.uk>
Subject: [PATCH] msm: platsmp: actually read core count in get_core_count

Previously we just assumed there were CONFIG_NR_CPUS cpus present in
the system. Instead, figure out the number of cpus from the MIDR
register.

Signed-off-by: Jeff Ohlstein <johlstei@...eaurora.org>
---
 arch/arm/mach-msm/platsmp.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-msm/platsmp.c b/arch/arm/mach-msm/platsmp.c
index 0f427bc..58c1d7b 100644
--- a/arch/arm/mach-msm/platsmp.c
+++ b/arch/arm/mach-msm/platsmp.c
@@ -18,6 +18,7 @@
 
 #include <asm/hardware/gic.h>
 #include <asm/cacheflush.h>
+#include <asm/cputype.h>
 #include <asm/mach-types.h>
 
 #include <mach/msm_iomap.h>
@@ -40,6 +41,12 @@ volatile int pen_release = -1;
 
 static DEFINE_SPINLOCK(boot_lock);
 
+static inline int get_core_count(void)
+{
+	/* 1 + the PART[1:0] field of MIDR */
+	return ((read_cpuid_id() >> 4) & 3) + 1;
+}
+
 void __cpuinit platform_secondary_init(unsigned int cpu)
 {
 	/* Configure edge-triggered PPIs */
@@ -147,9 +154,9 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
  */
 void __init smp_init_cpus(void)
 {
-	unsigned int i;
+	unsigned int i, ncores = get_core_count();
 
-	for (i = 0; i < NR_CPUS; i++)
+	for (i = 0; i < ncores; i++)
 		set_cpu_possible(i, true);
 }
 
-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

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