There is a subtle race in the CPU hotplug code, where a CPU which has
been offlined can online itself before being requested, which results
in things going astray on the next online/offline cycle.

What happens in the normal online/offline/online cycle is:

	CPU0			CPU3
	requests boot of CPU3
	pen_release = 3
	flush cache line
				checks pen_release, reads 3
				starts boot
				pen_release = -1
	... requests CPU3 offline ...
				... dies ...
				checks pen_release, reads -1
	requests boot of CPU3
	pen_release = 3
	flush cache line
				checks pen_release, reads 3
				starts boot
				pen_release = -1

However, as the write of -1 of pen_release is not fully flushed back to
memory, and the checking of pen_release is done with caches disabled,
this allows CPU3 the opportunity to read the old value of pen_release:

	CPU0			CPU3
	requests boot of CPU3
	pen_release = 3
	flush cache line
				checks pen_release, reads 3
				starts boot
				pen_release = -1
	... requests CPU3 offline ...
				... dies ...
				checks pen_release, reads 3
				starts boot
				pen_release = -1
	requests boot of CPU3
	pen_release = 3
	flush cache line

Fix this by grouping the write of pen_release along with its cache line
flushing code to ensure that any update to pen_release is always pushed
out to physical memory.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

All platforms call trace_hardirqs_off() in their secondary startup code,
so move this into the core SMP code - it doesn't need to be in the
per-platform code.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

There is a certain amount of smp_prepare_cpus() which doesn't belong
in the platform support code - that is, code which is invariant to the
SMP implementation.  Move this code into arch/arm/kernel/smp.c, and
add a platform_ prefix to the original function.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Milo is an old boot loader, which is no longer relevant for these
platforms.  References to it are misleading.  Move the code out
of poke_milo(), and remove references to milo in comments.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

We don't need this small function as well as scu_get_core_count()
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

scu_get_core_count() never returns zero cores, so we don't need to
check and correct if ncores is zero.

Tegra was missing the check against NR_CPUS, leading to a potential
bitfield overflow if this becomes the case.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Ensure that the number of CPUs is sanity checked before setting
the number of possible CPUs.  This avoids any chance of overflowing
the cpu_possible bitmap.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This allows us to use smp_cross_call() to trigger a number of different
software generated interrupts, rather than combining them all on one
SGI.  Recover the SGI number via do_IPI.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The platsmp.c file defines the REALVIEW_SYS_FLAGS* macros which are
already present in platform.h. Just use the latter.
Signed-off-by: NColin Tuckley <colin.tuckley@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch sets bit 0 in the startup address passed to the secondary
CPUs so that they branch into Thumb-2 mode.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This is a RealView platform supporting core tiles with ARM11MPCore,
Cortex-A8 or Cortex-A9 (multicore) processors. It has support for MMC,
CompactFlash, PCI-E.
Signed-off-by: NColin Tuckley <colin.tuckley@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

Convert cpu_*_mask bit twiddling to the new set_cpu_*() API.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The SCU can be used by non-realview platforms, so make it visible
for other people to use rather than having them copy the header file.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Having discussed broadcast tick support with Thomas Glexiner, the
broadcast tick devices should be registered with a higher rating
than the global tick device, and it should have the ONESHOT and
PERIODIC feature flags set.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NThomas Glexiner <tglx@linutronix.de>

smp_cross_call_done() is a no-op for MPCore, and since it's only
used by platform code, there's no point in having it unless it's
doing something.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The ARM SMP code wasn't properly updated for the cpumask changes, which
results in smp_timer_broadcast() broadcasting ticks to non-online CPUs.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-realview/platsmp.c:140: error: 'jiffies' undeclared (first use in this function)
drivers/amba/bus.c:246: error: 'NO_IRQ' undeclared (first use in this function)
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Some of the calls weren't necessary and some others were duplicated.
This patch tidies up the platsmp.c file.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

All the cases where the local timer for a CPU is accessed happen on the
corresponding current CPU, hence no need to access the per-CPU local
timer mappings.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch adds the necessary definitions and Kconfig entries to enable
Cortex-A9 (ARMv7 SMP) tiles on the RealView/EB board.
Signed-off-by: NJon Callan <Jon.Callan@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This just leaves include/asm-arm/plat-* to deal with.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Remove includes of asm/hardware.h in addition to asm/arch/hardware.h.
Then, since asm/hardware.h only exists to include asm/arch/hardware.h,
update everything to directly include asm/arch/hardware.h and remove
asm/hardware.h.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch annotates the platform_secondary_init function in
arch/arm/mach-realview/platsmp.c with trace_hardirqs_off to avoid a
warning when LOCKDEP and TRACE_IRQFLAGS are enabled.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch annotates the platform_secondary_init function in
arch/arm/mach-realview/platsmp.c with trace_hardirqs_off to avoid a
warning when LOCKDEP and TRACE_IRQFLAGS are enabled.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch adds the initialisation calls for the SMP support on the
PB11MPCore platform.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch moves the SCU initialisation from __v6_setup to the
smp_prepare_cpus() function as it relies on platform-specific
settings. Changes to get_core_count() are mainly for allowing cleaner
code with the upcoming PB11MPCore patches.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch adds the core-tile detection and only enables devices if the
corresponding tile is present. It currently detects the ARM11MPCore via
the core_tile_eb11mp() macro.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch moves the platform specific definitions from platform.h into
the board-eb.h file. It drops the INT_* definitions as they are no
longer used in irqs.h (moved to board-eb.h). It renames REALVIEW_*
macros to REALVIEW_EB_* or REALVIEW_EB11MP_* to distinguish between
standard EB and EB + the ARM11MPCore tile. The platform.h file contains
common definitions to the RealView platforms and it is only directly
included in board-*.h files.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch adds dummy local timers for each CPU so that the board clock
device is used to broadcast events to the other CPUs. The patch also
adds the declaration for the dummy_timer_setup function (the equivalent
of local_timer_setup when CONFIG_LOCAL_TIMERS is not set).

Due to the way clockevents work, the dummy timer on the first CPU has to
be registered before the board timer.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

In some situations, the pen_release store in platform_secondary_init()
may stay forever in the write buffer while the CPU is waiting on the
boot_lock to be released in boot_secondary(). The primary CPU could
never see the pen_release update without the barriers.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The current implementation only assumes one GIC to be present in the
system. However, there are platforms with more than one cascaded interrupt
controllers (RealView/EB MPCore for example).
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

A change to the SMP initialisation caused the following oops:

 CPU1: Booted secondary processor
 CPU1: D VIPT write-back cache
 CPU1: I cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets
 CPU1: D cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets
 <7>Calibrating delay loop... 83.14 BogoMIPS (lpj=415744)
 <1>Unable to handle kernel NULL pointer dereference at virtual address 0000001c
 ...
 PC is at enqueue_task+0x1c/0x64
 LR is at activate_task+0xcc/0xe4

SMP initialisation now requires cpu_possible_map to be initialised in
setup_arch().  Move this from smp_prepare_cpus() to smp_init_cpus()
and call it from our setup_arch() if CONFIG_SMP is enabled.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move __io_address to arch-realview/hardware.h, drop core.h from platsmp.c
and localtimer.c, and include asm/io.h where required.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add platform specific parts for local timer support for the
Realview board.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add SMP support for the MPcore tile fitted to the Realview ARM
platform.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Since the secondary CPUs will not be operating in symetric mode
while they are held in the pen, we need to ensure that the write
to pen_release is visible to them, by flushing the cache.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>