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

Brian Norris
2014-07-31T02:36:35Z

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:
> > +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