Subject: [PATCH 3/4] ARM: VExpress: Switch to generic SCU routines

From: [email-masked] (Anton Vorontsov)
Date: Tue, 27 Jul 2010 21:11:44 +0400

This shrinks platform-specific code quite a bit.

Signed-off-by: Anton Vorontsov <[email-masked]>
---
 arch/arm/mach-vexpress/Makefile  |    2 +-
 arch/arm/mach-vexpress/headsmp.S |   39 ----------
 arch/arm/mach-vexpress/platsmp.c |  150 ++++----------------------------------
 3 files changed, 15 insertions(+), 176 deletions(-)
 delete mode 100644 arch/arm/mach-vexpress/headsmp.S

diff --git a/arch/arm/mach-vexpress/Makefile b/arch/arm/mach-vexpress/Makefile
index 1b71b77..6533d11 100644
--- a/arch/arm/mach-vexpress/Makefile
+++ b/arch/arm/mach-vexpress/Makefile
@@ -4,5 +4,5 @@
 
 obj-y					:= v2m.o
 obj-$(CONFIG_ARCH_VEXPRESS_CA9X4)	+= ct-ca9x4.o
-obj-$(CONFIG_SMP)			+= platsmp.o headsmp.o
+obj-$(CONFIG_SMP)			+= platsmp.o
 obj-$(CONFIG_LOCAL_TIMERS)		+= localtimer.o
diff --git a/arch/arm/mach-vexpress/headsmp.S b/arch/arm/mach-vexpress/headsmp.S
deleted file mode 100644
index 8a78ff6..0000000
--- a/arch/arm/mach-vexpress/headsmp.S
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- *  linux/arch/arm/mach-vexpress/headsmp.S
- *
- *  Copyright (c) 2003 ARM Limited
- *  All Rights Reserved
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#include <linux/linkage.h>
-#include <linux/init.h>
-
-	__INIT
-
-/*
- * Versatile Express specific entry point for secondary CPUs.  This
- * provides a "holding pen" into which all secondary cores are held
- * until we're ready for them to initialise.
- */
-ENTRY(vexpress_secondary_startup)
-	mrc	p15, 0, r0, c0, c0, 5
-	and	r0, r0, #15
-	adr	r4, 1f
-	ldmia	r4, {r5, r6}
-	sub	r4, r4, r5
-	add	r6, r6, r4
-pen:	ldr	r7, [r6]
-	cmp	r7, r0
-	bne	pen
-
-	/*
-	 * we've been released from the holding pen: secondary_stack
-	 * should now contain the SVC stack for this core
-	 */
-	b	secondary_startup
-
-1:	.long	.
-	.long	pen_release
diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c
index 6709706..2d4146f 100644
--- a/arch/arm/mach-vexpress/platsmp.c
+++ b/arch/arm/mach-vexpress/platsmp.c
@@ -9,15 +9,9 @@
  * published by the Free Software Foundation.
  */
 #include <linux/init.h>
-#include <linux/errno.h>
-#include <linux/delay.h>
-#include <linux/device.h>
-#include <linux/jiffies.h>
 #include <linux/smp.h>
 #include <linux/io.h>
 
-#include <asm/cacheflush.h>
-#include <asm/localtimer.h>
 #include <asm/smp_scu.h>
 #include <asm/unified.h>
 
@@ -27,21 +21,11 @@
 
 #include "core.h"
 
-extern void vexpress_secondary_startup(void);
-
-/*
- * control for which core is the next to come out of the secondary
- * boot "holding pen"
- */
-volatile int __cpuinitdata pen_release = -1;
-
 static void __iomem *scu_base_addr(void)
 {
 	return MMIO_P2V(A9_MPCORE_SCU);
 }
 
-static DEFINE_SPINLOCK(boot_lock);
-
 void __cpuinit platform_secondary_init(unsigned int cpu)
 {
 	trace_hardirqs_off();
@@ -53,138 +37,32 @@ void __cpuinit platform_secondary_init(unsigned int cpu)
 	 */
 	gic_cpu_init(0, gic_cpu_base_addr);
 
-	/*
-	 * let the primary processor know we're out of the
-	 * pen, then head off into the C entry point
-	 */
-	pen_release = -1;
-	smp_wmb();
-
-	/*
-	 * Synchronise with the boot thread.
-	 */
-	spin_lock(&boot_lock);
-	spin_unlock(&boot_lock);
+	scu_secondary_init(cpu);
 }
 
 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
-	unsigned long timeout;
-
-	/*
-	 * Set synchronisation state between this boot processor
-	 * and the secondary one
-	 */
-	spin_lock(&boot_lock);
-
-	/*
-	 * This is really belt and braces; we hold unintended secondary
-	 * CPUs in the holding pen until we're ready for them.  However,
-	 * since we haven't sent them a soft interrupt, they shouldn't
-	 * be there.
-	 */
-	pen_release = cpu;
-	__cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release));
-	outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
-
-	/*
-	 * Send the secondary CPU a soft interrupt, thereby causing
-	 * the boot monitor to read the system wide flags register,
-	 * and branch to the address found there.
-	 */
-	smp_cross_call(cpumask_of(cpu));
-
-	timeout = jiffies + (1 * HZ);
-	while (time_before(jiffies, timeout)) {
-		smp_rmb();
-		if (pen_release == -1)
-			break;
-
-		udelay(10);
-	}
-
-	/*
-	 * now the secondary core is starting up let it run its
-	 * calibrations, then wait for it to finish
-	 */
-	spin_unlock(&boot_lock);
-
-	return pen_release != -1 ? -ENOSYS : 0;
+	return scu_boot_secondary(cpu, idle);
 }
 
-/*
- * Initialise the CPU possible map early - this describes the CPUs
- * which may be present or become present in the system.
- */
 void __init smp_init_cpus(void)
 {
-	void __iomem *scu_base = scu_base_addr();
-	unsigned int i, ncores;
-
-	ncores = scu_base ? scu_get_core_count(scu_base) : 1;
-
-	/* sanity check */
-	if (ncores == 0) {
-		printk(KERN_ERR
-		       "vexpress: strange CM count of 0? Default to 1\n");
-
-		ncores = 1;
-	}
+	scu_init_cpus(scu_base_addr());
+}
 
-	if (ncores > NR_CPUS) {
-		printk(KERN_WARNING
-		       "vexpress: no. of cores (%d) greater than configured "
-		       "maximum of %d - clipping\n",
-		       ncores, NR_CPUS);
-		ncores = NR_CPUS;
-	}
+/* If there are more than one CPU let them know where to start. */
+static void __init smp_point_cpus(void)
+{
+	if (num_present_cpus() <= 1)
+		return;
 
-	for (i = 0; i < ncores; i++)
-		set_cpu_possible(i, true);
+	writel(~0, MMIO_P2V(V2M_SYS_FLAGSCLR));
+	writel(BSYM(virt_to_phys(scu_secondary_startup)),
+	       MMIO_P2V(V2M_SYS_FLAGSSET));
 }
 
 void __init smp_prepare_cpus(unsigned int max_cpus)
 {
-	unsigned int ncores = num_possible_cpus();
-	unsigned int cpu = smp_processor_id();
-	int i;
-
-	smp_store_cpu_info(cpu);
-
-	/*
-	 * are we trying to boot more cores than exist?
-	 */
-	if (max_cpus > ncores)
-		max_cpus = ncores;
-
-	/*
-	 * Initialise the present map, which describes the set of CPUs
-	 * actually populated at the present time.
-	 */
-	for (i = 0; i < max_cpus; i++)
-		set_cpu_present(i, true);
-
-	/*
-	 * Initialise the SCU if there are more than one CPU and let
-	 * them know where to start.
-	 */
-	if (max_cpus > 1) {
-		/*
-		 * Enable the local timer or broadcast device for the
-		 * boot CPU, but only if we have more than one CPU.
-		 */
-		percpu_timer_setup();
-
-		scu_enable(scu_base_addr());
-
-		/*
-		 * Write the address of secondary startup into the
-		 * system-wide flags register. The boot monitor waits
-		 * until it receives a soft interrupt, and then the
-		 * secondary CPU branches to this address.
-		 */
-		writel(~0, MMIO_P2V(V2M_SYS_FLAGSCLR));
-		writel(BSYM(virt_to_phys(vexpress_secondary_startup)),
-			MMIO_P2V(V2M_SYS_FLAGSSET));
-	}
+	scu_prepare_cpus(scu_base_addr(), max_cpus);
+	smp_point_cpus();
 }
-- 
1.7.0.5