This patch supports the cache handling for some old Feroceon cores for
which the CPU ID is like 0x41159260. This is a complement to
commit ab6d15d506.
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
When a kthread function returns, it branches to do_exit(). However, the
unwinding information isn't valid anymore and any stack trace caused by
do_exit() may be incorrect. This patch adds a kernel_thread_exit()
function and annotated with '.cantunwind' so that the unwinder stops
when reaching it.
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There are situations where the unwinder goes beyond stack boundaries and
unwinds random data. This patch moves the stack boundaries check after
the unwind_exec_insn() call and adds an extra check for possible
infinite loops (like "mov pc, lr" with pc == lr).
The patch also fixes a bug in the unwind instructions interpreter. The
0xb0 instruction can only set PC to LR if this wasn't already set by
a previous instruction (this is used on exceptions taken while in kernel
mode where svc_entry is annotated with ".save {r0 - pc}").
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Not discarding these sections when hotplug isn't available prevents the
kernel from building.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
From: Min Zhang <mzhang@mvista.com>
Add alignment fault fixup support for 32-bit Thumb-2 LDM, LDRD, POP,
PUSH, STM and STRD instructions. Alignment fault fixup support for
the remaining 32-bit Thumb-2 load/store instruction cases is not
included since ARMv6 and later processors include hardware support
for loads and stores of unaligned words and halfwords.
Signed-off-by: Min Zhang <mzhang@mvista.com>
Signed-off-by: George G. Davis <gdavis@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The cpu member of struct irq_desc was recently renamed to node. The
patch renames the ARM references to the old member.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This header file is needed for twd_base.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This function was only used by pci_claim_resource(), and the last commit
deleted that use.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* akpm: (182 commits)
fbdev: bf54x-lq043fb: use kzalloc over kmalloc/memset
fbdev: *bfin*: fix __dev{init,exit} markings
fbdev: *bfin*: drop unnecessary calls to memset
fbdev: bfin-t350mcqb-fb: drop unused local variables
fbdev: blackfin has __raw I/O accessors, so use them in fb.h
fbdev: s1d13xxxfb: add accelerated bitblt functions
tcx: use standard fields for framebuffer physical address and length
fbdev: add support for handoff from firmware to hw framebuffers
intelfb: fix a bug when changing video timing
fbdev: use framebuffer_release() for freeing fb_info structures
radeon: P2G2CLK_ALWAYS_ONb tested twice, should 2nd be P2G2CLK_DAC_ALWAYS_ONb?
s3c-fb: CPUFREQ frequency scaling support
s3c-fb: fix resource releasing on error during probing
carminefb: fix possible access beyond end of carmine_modedb[]
acornfb: remove fb_mmap function
mb862xxfb: use CONFIG_OF instead of CONFIG_PPC_OF
mb862xxfb: restrict compliation of platform driver to PPC
Samsung SoC Framebuffer driver: add Alpha Channel support
atmel-lcdc: fix pixclock upper bound detection
offb: use framebuffer_alloc() to allocate fb_info struct
...
Manually fix up conflicts due to kmemcheck in mm/slab.c
* create mm/init-mm.c, move init_mm there
* remove INIT_MM, initialize init_mm with C99 initializer
* unexport init_mm on all arches:
init_mm is already unexported on x86.
One strange place is some OMAP driver (drivers/video/omap/) which
won't build modular, but it's already wants get_vm_area() export.
Somebody should look there.
[akpm@linux-foundation.org: add missing #includes]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch introduces the Openmoko GTA02 machine definition.
Much of the code is based on Harald Welte's work, although it
has been largely rewritten several times.
This is intended to be the minimum machine definition to boot and
be able to run a rootfs from NAND on GTA02 / FreeRunner. It does
not bring up the framebuffer / Glamo and lacks many other peripheral
drivers from outside the SoC. But once we have this basis in
mainline kernel, we will be able to introduce the other drivers
and add them here.
Thanks to Sven Rebhan <odinshorse@googlemail.com> for his fixes to this
patch (Kconfig and defconfig files).
Signed-off-by: Andy Green <andy@warmcat.com>
Signed-off-by: Nelson Castillo <arhuaco@freaks-unidos.net>
[ben-linux@fluff.org: Fix the GPIO definitions]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This patch provides initial support for CPU frequency scaling on the
Samsung S3C ARM processors. Currently only S3C6410 processors are
supported, though addition of another data table with supported clock
rates should be sufficient to enable support for further CPUs.
Use the regulator framework to provide optional support for DVFS in
the S3C cpufreq driver. When a software controllable regulator is
configured the driver will use it to lower the supply voltage when
running at a lower frequency, giving improved power savings.
When regulator support is disabled or no regulator can be obtained
for VDDARM the driver will fall back to scaling only the frequency.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This allows the S3C64XX IIS drivers to be converted to the standard
driver model and allows fixes there for problems with attempting to
acquire the clocks for the IIS blocks via the clock API.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Currently pcm990 camera bus-width management functions request a GPIO and never
free it again. With this approach the GPIO extender driver cannot be unloaded
once camera drivers have been loaded, also unloading theb i2c-pxa bus driver
produces errors, because the GPIO extender driver cannot unregister properly.
Another problem is, that if camera drivers are once loaded before the GPIO
extender driver, the platform code marks the GPIO unavailable and only a reboot
helps to recover. Adding an explicit free_bus method and using it in mt9m001
and mt9v022 drivers fixes these problems.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The wm8731 driver has been converted to register using the standard I2C
device registration mechanism so we can now do the registration in the
arch/arm code as normal.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
Maxim 1586 V3 gain can be configured by external resistors
(R24, R25) connected to the FB3 pin. To avoid accidental
overvoltage, it now requires this gain to be configured
explicitly.
Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
On this board, the PXA272 CPU voltage VCC_CORE is provided
by a Maxim 1586 voltage regulator. Use the regulator
framework to provide VCC_CORE control. When cpufreq will be
updated to ask for vcc_core, this will optimize power
drained by the board.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
On this board, the PXA270 CPU voltage VCC_CORE is provided
by a Maxim 1587A voltage regulator configured to provide
1.55 V maximum voltage for 624 MHz operation.
Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
After commit 6b849bcff0 (ASoC: Convert PXA
AC97 driver to probe with the platform device) AC97 controller device
should be registered explicitly for both ASoC and generic AC97 drivers
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
Register userspace-consumer devices to allow userspace control of
voltage regulators supplying GPS and GPRS modules
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
Driver support for the new high-speed/OtG block that is
in the newer line of Samsung SoC devices such as the
S3C64XX series.
This driver does not currntly have DMA support enabled due
to issues with buffer alignment which need to be sorted out.
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Just a working, starting point config file for the board.
Signed-off-by: Michel Pollet <buserror@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
The MINI2440 is a chinese made s3c2440 development board with
a large set of peripherals.
This patch provides machine support for almost all the features
of the board.
Since it can come with various "options" fitted, a kernel parameter
is used to specify the lcd size, backlight control and touchscreen.
Signed-off-by: Michel Pollet <buserror@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Without incrementing the counter the next window setup will overwrite
the SRAM mapping.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (417 commits)
MAINTAINERS: EB110ATX is not ebsa110
MAINTAINERS: update Eric Miao's email address and status
fb: add support of LCD display controller on pxa168/910 (base layer)
[ARM] 5552/1: ep93xx get_uart_rate(): use EP93XX_SYSCON_PWRCNT and EP93XX_SYSCON_PWRCN
[ARM] pxa/sharpsl_pm: zaurus needs generic pxa suspend/resume routines
[ARM] 5544/1: Trust PrimeCell resource sizes
[ARM] pxa/sharpsl_pm: cleanup of gpio-related code.
[ARM] pxa/sharpsl_pm: drop set_irq_type calls
[ARM] pxa/sharpsl_pm: merge pxa-specific code into generic one
[ARM] pxa/sharpsl_pm: merge the two sharpsl_pm.c since it's now pxa specific
[ARM] sa1100: remove unused collie_pm.c
[ARM] pxa: fix the conflicting non-static declarations of global_gpios[]
[ARM] 5550/1: Add default configure file for w90p910 platform
[ARM] 5549/1: Add clock api for w90p910 platform.
[ARM] 5548/1: Add gpio api for w90p910 platform
[ARM] 5551/1: Add multi-function pin api for w90p910 platform.
[ARM] Make ARM_VIC_NR depend on ARM_VIC
[ARM] 5546/1: ARM PL022 SSP/SPI driver v3
ARM: OMAP4: SMP: Update defconfig for OMAP4430
ARM: OMAP4: SMP: Enable SMP support for OMAP4430
...
Without this, the default implementation is a no op which is completely
wrong with a VIVT cache, and usage of sg_copy_buffer() produces
unpredictable results.
Tested-by: Sebastian Andrzej Siewior <bigeasy@breakpoint.cc>
CC: stable@kernel.org
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch removes unused asm/suspend.h files for
the following architectures:
alpha, arm, ia64, m68k, mips, s390, um
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
ep93xx: get_uart_rate() uses the constants EP93XX_SYSCON_CLOCK_CONTROL
and EP93XX_SYSCON_CLOCK_UARTBAUD, which no longer exist. Use
EP93XX_SYSCON_PWRCNT and EP93XX_SYSCON_PWRCNT_UARTBAUD instead
Signed-off-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The current asm-generic/page.h only contains the get_order
function, and asm-generic/uaccess.h only implements
unaligned accesses. This renames the file to getorder.h
and uaccess-unaligned.h to make room for new page.h
and uaccess.h file that will be usable by all simple
(e.g. nommu) architectures.
Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The existing asm-generic/atomic.h only defines the
atomic_long type. This renames it to atomic-long.h
so we have a place to add a truly generic atomic.h
that can be used on all non-SMP systems.
Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
This provides a reliable way for asm-generic/types.h and other
files to find out if it is running on a 32 or 64 bit platform.
We cannot use CONFIG_64BIT for this in headers that are included
from user space because CONFIG symbols are not available there.
We also cannot do it inside of asm/types.h because some headers
need the word size but cannot include types.h.
The solution is to introduce a new header <asm/bitsperlong.h>
that defines both __BITS_PER_LONG for user space and
BITS_PER_LONG for usage in the kernel. The asm-generic
version falls back to 32 bit unless the architecture overrides
it, which I did for all 64 bit platforms.
Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The existing asm-generic versions are incomplete and included
by some architectures. New architectures should be able
to use a generic version, so rename the existing files and
change all users, which lets us add the new files.
Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* 'for-2.6.31' of git://git.kernel.dk/linux-2.6-block: (153 commits)
block: add request clone interface (v2)
floppy: fix hibernation
ramdisk: remove long-deprecated "ramdisk=" boot-time parameter
fs/bio.c: add missing __user annotation
block: prevent possible io_context->refcount overflow
Add serial number support for virtio_blk, V4a
block: Add missing bounce_pfn stacking and fix comments
Revert "block: Fix bounce limit setting in DM"
cciss: decode unit attention in SCSI error handling code
cciss: Remove no longer needed sendcmd reject processing code
cciss: change SCSI error handling routines to work with interrupts enabled.
cciss: separate error processing and command retrying code in sendcmd_withirq_core()
cciss: factor out fix target status processing code from sendcmd functions
cciss: simplify interface of sendcmd() and sendcmd_withirq()
cciss: factor out core of sendcmd_withirq() for use by SCSI error handling code
cciss: Use schedule_timeout_uninterruptible in SCSI error handling code
block: needs to set the residual length of a bidi request
Revert "block: implement blkdev_readpages"
block: Fix bounce limit setting in DM
Removed reference to non-existing file Documentation/PCI/PCI-DMA-mapping.txt
...
Manually fix conflicts with tracing updates in:
block/blk-sysfs.c
drivers/ide/ide-atapi.c
drivers/ide/ide-cd.c
drivers/ide/ide-floppy.c
drivers/ide/ide-tape.c
include/trace/events/block.h
kernel/trace/blktrace.c
* serial-from-alan: (79 commits)
moxa: prevent opening unavailable ports
imx: serial: use tty_encode_baud_rate to set true rate
imx: serial: add IrDA support to serial driver
imx: serial: use rational library function
lib: isolate rational fractions helper function
imx: serial: handle initialisation failure correctly
imx: serial: be sure to stop xmit upon shutdown
imx: serial: notify higher layers in case xmit IRQ was not called
imx: serial: fix one bit field type
imx: serial: fix whitespaces (no changes in functionality)
tty: use prepare/finish_wait
tty: remove sleep_on
sierra: driver interface blacklisting
sierra: driver urb handling improvements
tty: resolve some sierra breakage
timbuart: Fix the termios logic
serial: Added Timberdale UART driver
tty: Add URL for ttydev queue
devpts: unregister the file system on error
tty: Untangle termios and mm mutex dependencies
...
Using the iMX serial driver with an IrDA device
needs extra peripheral settings and specific
timing depending on the transmitter circuitry used.
Signed-off-by: Fabian Godehardt <fg@emlix.com>
Signed-off-by: Oskar Schirmer <os@emlix.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For suspend/resume to work, spitz needs pxa_pm_suspend/resume to be
called. Otherwise PSPR is not set properly, and system will die during
resume.
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
Replace calls to pxa_gpio_mode with respective gpio_request() /
gpio_direction_input(). In principle these calls can be dropped as
the only use of those GPIO are IRQs and IRQ code does setup GPIO
correctly.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
As pxa now is the only user of sharpsl_pm we can drop several startup
functions into generic code thus dropping several global functions.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
collie_pm was the only non-PXA user of sharpsl_pm. Now as it's gone we
can merge code into one single file to allow further cleanup.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
This file was never enabled in the mainline kernel, new ongoing work on
battery driver by Thomas Kunze makes it completely obsolete, so remove
it now.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
Add default configure file for w90p910 platform.
Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Add multi-function pin api for w90p910 platform.
Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* 'irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (76 commits)
x86, apic: Fix dummy apic read operation together with broken MP handling
x86, apic: Restore irqs on fail paths
x86: Print real IOAPIC version for x86-64
x86: enable_update_mptable should be a macro
sparseirq: Allow early irq_desc allocation
x86, io-apic: Don't mark pin_programmed early
x86, irq: don't call mp_config_acpi_gsi() if update_mptable is not enabled
x86, irq: update_mptable needs pci_routeirq
x86: don't call read_apic_id if !cpu_has_apic
x86, apic: introduce io_apic_irq_attr
x86/pci: add 4 more return parameters to IO_APIC_get_PCI_irq_vector(), fix
x86: read apic ID in the !acpi_lapic case
x86: apic: Fixmap apic address even if apic disabled
x86: display extended apic registers with print_local_APIC and cpu_debug code
x86: read apic ID in the !acpi_lapic case
x86: clean up and fix setup_clear/force_cpu_cap handling
x86: apic: Check rev 3 fadt correctly for physical_apic bit
x86/pci: update pirq_enable_irq() to setup io apic routing
x86/acpi: move setup io apic routing out of CONFIG_ACPI scope
x86/pci: add 4 more return parameters to IO_APIC_get_PCI_irq_vector()
...
This patch updates omap_4430sdp_defconfig to add SMP and LOCAL_TIMER
support for OMAP4430 SDP platform.
Additionally the defconfig is made in sync with 2.6.30-rc7
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
This patch adds SMP platform specific parts for local(mpu) timer support
for OMAP4430 platform. Each Cortex-a9 core has it's own local timer in the
MPU domain. These timers are not in wakeup domain.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
This patch adds SMP platform files support for OMAP4430SDP. TI's OMAP4430
SOC is based on ARM Cortex-A9 SMP architecture. It's a dual core SOC
with GIC used for interrupt handling and SCU for cache coherency.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Always creating the physical mapping should do no harm, so let's remove
the interface that was provided for its optional creation and make the
mapping static.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
We don't have to define resources to the minimal physical window size
as setup_cpu_win() will cope with smaller sizes already.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
The security accelerator which can act as a puppet player for the crypto
engine requires its commands in the sram. This patch adds support for the
phys mapping and creates a platform device for the actual driver.
[ nico: renamed device name from "mv,orion5x-crypto" to "mv_crypto"
so to match the module name and be more generic for Kirkwood use ]
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
This patch adds support for the switch found on the Netgear
WNR854T router.
Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
The Orion watchdog driver is also used on Kirkwood.
Convention is to use orion5x for stuff specific to 88F5xxx Orion chips
and simply "orion" for shared stuff across SoCs including Kirkwood.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
The Kirkwood architecture uses the same watchdog device as the Orion
architecture. This patch adds orion5x_wdt as a platform device for
Kirkwood.
Signed-off-by: Thomas Reitmayr <treitmayr@devbase.at>
Tested-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
The name of the define for the Reset-Out-Mask register as well as its
bit for the watchdog reset are changed to match the names used for
Kirkwood (which in turn match the processor specification more
closely). There is no functional change.
This patch prepares for adding orion5x_wdt as a platform device to
Kirkwood.
Signed-off-by: Thomas Reitmayr <treitmayr@devbase.at>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
To save power:
1. Enabling clock gating of unused peripherals
2. PLL and PHY of the units are also disabled (when possible.
Signed-off-by: Rabeeh Khoury <rabeeh@marvell.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Common resource and platform device structures are moved to common.c
and only the partition table and chip delay remains a per board
parameter.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Just like commit 1419468ab5, let's save some TLB entries by making
ioremap() return pointers into the boot-time Kirkwood peripheral
iotable mapping whenever someone tries to ioremap any part of the Kirkwood
peripheral register space.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
With a TCLK = 200MHz, the half period of the hardware timer is roughly
10 seconds. Because cnt32_to_63() must be called at least once per
half period of the base hardware counter, it is a bit risky to rely
solely on scheduling to generate frequent enough calls. Let's use a
kernel timer to ensure this.
Signed-off-by: Nicolas Pitre <nico@marvell.com>