linux/arch
Paul Walmsley ff2516fbef OMAP2+: wd_timer: disable on boot via hwmod postsetup mechanism
The OMAP watchdog timer IP blocks require a specific set of register
writes to occur before they will be disabled[1], even if the device
clocks appear to be disabled in the CM_*CLKEN registers.  In the MPU
watchdog case, failure to execute this reset sequence will eventually
cause the watchdog to reset the OMAP unexpectedly.

Previously, the code to disable this watchdog was manually called from
mach-omap2/devices.c during device initialization.  This causes the
watchdog to be unconditionally disabled for a portion of kernel
initialization.  This should be controllable by the board-*.c files,
since some system integrators will want full watchdog coverage of
kernel initialization.  Also, the watchdog disable code was not
connected to the hwmod shutdown code.  This means that calling
omap_hwmod_shutdown() will not, in fact, disable the watchdog, and the
goal of omap_hwmod_shutdown() is to be able to shutdown any on-chip
OMAP device.

To resolve the latter problem, populate the pre_shutdown pointer in
the watchdog timer hwmod classes with a function that executes the
watchdog shutdown sequence.  This allows the hwmod code to fully
disable the watchdog.

Then, to allow some board files to support watchdog coverage
throughout kernel initialization, add common code to mach-omap2/io.c
to cause the MPU watchdog to be disabled on boot unless a board file
specifically requests it to remain enabled.  Board files can do this
by changing the watchdog timer hwmod's postsetup state between the
omap2_init_common_infrastructure() and omap2_init_common_devices()
function calls.

1. OMAP34xx Multimedia Device Silicon Revision 3.1.x Rev. ZH
   [SWPU222H], Section 16.4.3.6, "Start/Stop Sequence for WDTs (Using
   WDTi.WSPR Register)"

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Charulatha Varadarajan <charu@ti.com>
2010-12-21 19:57:40 -07:00
..
alpha Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 2010-10-28 16:16:39 -07:00
arm OMAP2+: wd_timer: disable on boot via hwmod postsetup mechanism 2010-12-21 19:57:40 -07:00
avr32 Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 2010-10-28 16:16:39 -07:00
blackfin BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
cris Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 2010-10-28 16:16:39 -07:00
frv BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
h8300 BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
ia64 SCSI host lock push-down 2010-11-16 13:33:23 -08:00
m32r Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 2010-10-28 16:16:39 -07:00
m68k BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
m68knommu BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
microblaze Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 2010-10-28 16:16:39 -07:00
mips MIPS: Fix build errors in sc-mips.c 2010-12-17 19:44:35 +00:00
mn10300 clarify a usage constraint for cnt32_to_63() 2010-12-20 09:07:35 -08:00
parisc parisc: convert the rest of the irq handlers to simple/percpu 2010-12-04 11:15:19 -05:00
powerpc powerpc: Use call_rcu_sched() for pagetables 2010-11-30 10:42:20 +11:00
s390 [S390] nohz/s390: fix arch_needs_cpu() return value on offline cpus 2010-12-01 10:08:17 +01:00
score Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 2010-10-28 16:16:39 -07:00
sh sh: wire up accept4 syscall (non-multiplexed path) 2010-12-14 17:58:10 +09:00
sparc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6 2010-12-14 17:34:00 -08:00
tile arch/tile: handle rt_sigreturn() more cleanly 2010-12-17 16:59:29 -05:00
um uml: disable winch irq before freeing handler data 2010-11-25 06:50:39 +09:00
x86 Merge branches 'x86-fixes-for-linus' and 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-12-19 10:44:54 -08:00
xtensa Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 2010-10-28 16:16:39 -07:00
.gitignore
Kconfig jump label: Add work around to i386 gcc asm goto bug 2010-10-29 14:45:29 -04:00