Shared timer IRQs are not a good solution, however the Geode platform has
no APIC, IRQs are a scarce resource and there is no technical reason to
forbid it rightaway.  Increased latencies and overhead due to sharing are
still better than a driver refusing to load.
Signed-off-by: NJens Rottmann <JRottmann@LiPPERTEmbedded.de>
Acked-by: NAndres Salomon <dilinger@queued.net>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

On SMP-capable kernels (e.g.  generic distro kernel) the cs5535-clockevt
driver loads but is not actually used.

Setting cpumask to cpu_all_mask works for UP-only kernels, but if compiled
for SMP - though still running on the same UP hardware -
kernel/time/tick-common.c:tick_check_new_device() reads this as
"non-cpu-local" and silently ignores the device.

If we leave cpumask unset clockevents_register_device() will initialize it
and the cs5535-clockevt driver will be used no matter how the kernel was
compiled.  Should anyone ever manage to stick a CS553x in an SMP system
(is this even possible?) then a warning will be printed.  This is fine as
the cs5535-clockevt driver was never written/tested for SMP.

If bisecting led you here this patch may have exposed a pre-existing MFGPT
problem.  Configure for UP-only and re-check.
Signed-off-by: NJens Rottmann <JRottmann@LiPPERTEmbedded.de>
Acked-by: NAndres Salomon <dilinger@queued.net>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

My Collabora address is no longer enabled - update the MODULE_AUTHOR
fields of drivers to my current email address.
Signed-off-by: NAndres Salomon <dilinger@queued.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Due to a hardware limitation cs5535_mfgpt_free_timer() cannot actually
release the timer hardware, but it will at least free the now unreferenced
struct associated with it so calling it is the cleaner thing to do.
Signed-off-by: NJens Rottmann <JRottmann@LiPPERTEmbedded.de>
Acked-by: NAndres Salomon <dilinger@collabora.co.uk>
Cc: Jordan Crouse <jordan@cosmicpenguin.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

geode-mfgpt: restore previous behavior for selecting IRQ

The MFGPT IRQ used to be, in order of decreasing priority,
 * IRQ supplied by the user as a boot-time parameter,
 * IRQ previously set by the BIOS or another driver,
 * default IRQ given at compile time.

Return to this behavior, which got broken when splitting the
MFGPT/clocksource driver for 2.6.33-rc1.
Signed-off-by: NJens Rottmann <JRottmann@LiPPERTEmbedded.de>
Acked-by: NAndres Salomon <dilinger@collabora.co.uk>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is based on the old code in arch/x86/kernel/mfgpt_32.c, but is
modular and not Geode-specific.  There's no reason why the clock event
device needs to be registered so early at boot; the clockevent code is
perfectly capable of dynamic switching.

[akpm@linux-foundation.org: add linux/irq.h include]
Signed-off-by: NAndres Salomon <dilinger@collabora.co.uk>
Cc: Jordan Crouse <jordan@cosmicpenguin.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Chris Ball <cjb@laptop.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>