[PATCH v8 01/11] ARM: brcmstb: add infrastructure for ARM-based Broadcom STB SoCs

Hi Russell,

On Wed, Jul 30, 2014 at 10:26:35AM +0100, Russell King wrote:

On Mon, Jul 21, 2014 at 02:07:56PM -0700, Brian Norris wrote:

quoted

+static DEFINE_SPINLOCK(boot_lock);
+
+static void brcmstb_secondary_init(unsigned int cpu)
+{
+	/*
+	 * Synchronise with the boot thread.
+	 */
+	spin_lock(&boot_lock);
+	spin_unlock(&boot_lock);
+}
+
+static int brcmstb_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+	/*
+	 * set synchronisation state between this boot processor
+	 * and the secondary one
+	 */
+	spin_lock(&boot_lock);
+
+	/* Bring up power to the core if necessary */
+	if (brcmstb_cpu_get_power_state(cpu) == 0)
+		brcmstb_cpu_power_on(cpu);
+
+	brcmstb_cpu_boot(cpu);
+
+	/*
+	 * now the secondary core is starting up let it run its
+	 * calibrations, then wait for it to finish
+	 */
+	spin_unlock(&boot_lock);

I've just read through this code (because it caused my allmodconfig to
break) and spotted this.

Sorry about the allmodconfig problems. I never compile-tested with ARMv6
enabled. This look OK?

diff --git a/arch/arm/mach-bcm/Makefile b/arch/arm/mach-bcm/Makefile
index f3665121729b..5ce82b4ba931 100644
--- a/arch/arm/mach-bcm/Makefile
+++ b/arch/arm/mach-bcm/Makefile

@@ -32,6 +32,7 @@ obj-$(CONFIG_ARCH_BCM2835)	+= board_bcm2835.o
 obj-$(CONFIG_ARCH_BCM_5301X)	+= bcm_5301x.o
 
 ifeq ($(CONFIG_ARCH_BRCMSTB),y)
+CFLAGS_platsmp-brcmstb.o	+= -march=armv7-a
 obj-y				+= brcmstb.o
 obj-$(CONFIG_SMP)		+= headsmp-brcmstb.o platsmp-brcmstb.o
 endif

What function does boot_lock perform here?  Please, don't quote the
comments (I know where the comments came from) but what I want to hear
is your comments about why you decided to retain this.

You might glean a little more from my response to Rob, but I'm not sure
there was a good reason for retaining this. We do need to be sure the
CPU is fully powered online before bringing it out of reset, but the
spinlock seems overkill AFAICT.

Brian