Commit graph

6,429 commits

Author SHA1 Message Date
Russell King
c0bf31320d [ARM] omap: add support for bypassing DPLLs
This roughly corresponds with OMAP commits: 7d06c48, 3241b19,
88b5d9b, 18a5500, 9c909ac, 5c6497b, 8b1f0bd, 2ac1da8.

For both OMAP2 and OMAP3, we note the reference and bypass clocks in
the DPLL data structure.  Whenever we modify the DPLL rate, we first
ensure that both the reference and bypass clocks are enabled.  Then,
we decide whether to use the reference and DPLL, or the bypass clock
if the desired rate is identical to the bypass rate, and program the
DPLL appropriately.  Finally, we update the clock's parent, and then
disable the unused clocks.

This keeps the parents correctly balanced, and more importantly ensures
that the bypass clock is running whenever we reprogram the DPLL.  This
is especially important because the procedure for reprogramming the DPLL
involves switching to the bypass clock.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 17:28:30 +00:00
Hartley Sweeten
9dd446f657 [ARM] 5405/1: ep93xx: remove unused gesbc9312.h header
Remove the gesbc9312.h header since it is unused.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 16:13:02 +00:00
Makito SHIOKAWA
9da616fb99 [ARM] 5404/1: Fix condition in arm_elf_read_implies_exec() to set READ_IMPLIES_EXEC
READ_IMPLIES_EXEC must be set when:
o binary _is_ an executable stack (i.e. not EXSTACK_DISABLE_X)
o processor architecture is _under_ ARMv6 (XN bit is supported from ARMv6)

Signed-off-by: Makito SHIOKAWA <lkhmkt@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 14:45:27 +00:00
Russell King
41f3103fcf [ARM] omap: fix clock reparenting in omap2_clk_set_parent()
When changing the parent of a clock, it is necessary to keep the
clock use counts balanced otherwise things the parent state will
get corrupted.  Since we already disable and re-enable the clock,
we might as well use the recursive versions instead.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 13:25:16 +00:00
Catalin Marinas
7db21712ae [ARM] 5397/1: RealView: Add support for the ISP1761 USB chip
This patch adds the platform_device and resource structures for the USB
ISP1761 chip, usable with the in-kernel isp1760 driver.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 11:30:27 +00:00
Catalin Marinas
6be62ba215 [ARM] 5396/1: RealView: Use PATA_PLATFORM to access the CompactFlash
This driver adds the platform_device definitions to allow the use of
CompactFlash on the RealView PB11MPCore and PB-A8 platforms. Note that
the CompactFlash controller is expected to be initialised by the Boot
Monitor and support the True IDE mode.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 11:30:26 +00:00
Catalin Marinas
533ad5e60c [ARM] 5395/1: RealView: Add support for the DS1338 RTC chip
This chip is on the I2C bus on the RealView and Versatile boards. The
patch adds the i2c_board_info definition for this device and registers
it with the I2C subsystem.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 11:30:25 +00:00
Alexander Schulz
eab184c236 [ARM] 5363/1: Shark cleanup and new defconfig
This includes a new defconfig for the Shark and some changes to
the mach-shark directory to avoid namespace pollution and to
switch the rtc to the newer driver.

Signed-off-by: Alexander Schulz <alex@shark-linux.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 11:30:20 +00:00
Daniel Silverstone
1144d6535f [ARM] 5376/1: S3C24XX: Fix sparse errors in platform uncompress.h
Ensure __iomem attribute is __force 'd off in the minimal
__raw_writel() implementation.

Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 11:30:19 +00:00
Catalin Marinas
adf8b37baf [ARM] 5386/2: unwind: Add Makefile and Kconfig entries for ARM stack unwinding
This patch also makes the frame pointer default to y only if
!ARM_UNWIND. LOCKDEP no longer selects FRAME_POINTER if ARM_UNWIND is
enabled.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 11:30:18 +00:00
Catalin Marinas
c4c5716e16 [ARM] 5385/2: unwind: Add unwinding information to exception entry points
This is needed to allow or stop the unwinding at certain points in the
kernel like exception entries.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 11:27:35 +00:00
Catalin Marinas
2e1926e7b5 [ARM] 5384/1: unwind: Add stack unwinding support for loadable modules
This patch adds ELF section parsing for the unwinding tables in loadable
modules together with the PREL31 relocation symbol resolving.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 11:27:19 +00:00
Catalin Marinas
bff595c15c [ARM] 5383/2: unwind: Add core support for ARM stack unwinding
This patch adds the main functionality for parsing the stack unwinding
information generated by the ARM EABI toolchains. The unwinding
information consists of an index with a pair of words per function and a
table with unwinding instructions. For more information, see "Exception
Handling ABI for the ARM Architecture" at:

http://infocenter.arm.com/help/topic/com.arm.doc.subset.swdev.abi/index.html

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 11:26:24 +00:00
Nicolas Pitre
3fd9825c42 [ARM] 5402/1: fix a case of wrap-around in sanity_check_meminfo()
In the non highmem case, if two memory banks of 1GB each are provided,
the second bank would evade suppression since its virtual base would
be 0.  Fix this by disallowing any memory bank which virtual base
address is found to be lower than PAGE_OFFSET.

Reported-by: Lennert Buytenhek <buytenh@marvell.com>

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-19 09:49:45 +00:00
Nicolas Pitre
fd4b9b3650 [ARM] 5401/1: Orion: fix edge triggered GPIO interrupt support
The GPIO interrupts can be configured as either level triggered or edge
triggered, with a default of level triggered.  When an edge triggered
interrupt is requested, the gpio_irq_set_type method is called which
currently switches the given IRQ descriptor between two struct irq_chip
instances: orion_gpio_irq_level_chip and orion_gpio_irq_edge_chip. This
happens via __setup_irq() which also calls irq_chip_set_defaults() to
assign default methods to uninitialized ones.  The problem is that
irq_chip_set_defaults() is called before the irq_chip reference is
switched, leaving the new irq_chip (orion_gpio_irq_edge_chip in this
case) with uninitialized methods such as chip->startup() causing a kernel
oops.

Many solutions are possible, such as making irq_chip_set_defaults() global
and calling it from gpio_irq_set_type(), or calling __irq_set_trigger()
before irq_chip_set_defaults() in __setup_irq().  But those require
modifications to the generic IRQ code which might have adverse effect on
other architectures, and that would still be a fragile arrangement.
Manually copying the missing methods from within gpio_irq_set_type()
would be really ugly and it would break again the day new methods with
automatic defaults are added.

A better solution is to have a single irq_chip instance which can deal
with both edge and level triggered interrupts.  It is also a good idea
to switch the IRQ handler instead, as the edge IRQ handler allows for
one edge IRQ event to be queued as the IRQ is actually masked only when
that second IRQ is received, at which point the hardware can queue an
additional IRQ event, making edge triggered interrupts a bit more
reliable.

Tested-by: Martin Michlmayr <tbm@cyrius.com>

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-17 22:37:09 +00:00
Gregory CLEMENT
744f659272 [ARM] 5400/1: Add support for inverted rdy_busy pin for Atmel nand device controller
Add support for inverted rdy_busy pin for Atmel nand device controller
It will fix building error on NeoCore926 board.

Acked-by: Andrew Victor <linux@maxim.org.za>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Gregory CLEMENT <gclement@adeneo.adetelgroup.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-16 21:40:39 +00:00
Patrick Ohly
cb9eff0978 net: new user space API for time stamping of incoming and outgoing packets
User space can request hardware and/or software time stamping.
Reporting of the result(s) via a new control message is enabled
separately for each field in the message because some of the
fields may require additional computation and thus cause overhead.
User space can tell the different kinds of time stamps apart
and choose what suits its needs.

When a TX timestamp operation is requested, the TX skb will be cloned
and the clone will be time stamped (in hardware or software) and added
to the socket error queue of the skb, if the skb has a socket
associated with it.

The actual TX timestamp will reach userspace as a RX timestamp on the
cloned packet. If timestamping is requested and no timestamping is
done in the device driver (potentially this may use hardware
timestamping), it will be done in software after the device's
start_hard_xmit routine.

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-15 22:43:33 -08:00
Andrew Victor
2b768b6cdb [ARM] 5391/1: AT91: Enable GPIO clocks earlier
Enable the GPIO clocks earlier in the initialization sequence.  This
allow the board-setup code to read and set GPIO pins.

Signed-off-by: Marc Pignat <marc.pignat@hevs.ch>
Signed-off-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-14 16:03:36 +00:00
Andrew Victor
2af29b7861 [ARM] 5390/1: AT91: Watchdog fixes
The recently merged AT91SAM9 watchdog driver uses the
AT91SAM9X_WATCHDOG config variable, whereas the original version of
the driver (and the platform support code) used AT91SAM9_WATCHDOG.
This causes the watchdog platform_device to never be registered, and
therefore the driver not to be initialized.

This patch:
- updates the platform support code to use AT91SAM9X_WATCHDOG.
- includes <linux/io.h> to fix compile error (same fix as was applied
to at91rm9200_wdt.c)
- fixes comment regarding watchdog clock-rates in at91rm9200.

Signed-off-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-14 16:01:57 +00:00
Russell King
abf239657b [ARM] omap: fix _omap2_clksel_get_src_field()
_omap2_clksel_get_src_field() was returning the first entry which was
either the default _or_ applicable to the SoC.  This is wrong - we
should be returning the first default which is applicable to the SoC.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-14 13:25:38 +00:00
Russell King
9132f1b453 [ARM] omap: fix omap2_divisor_to_clksel() error return value
The error checks for omap2_divisor_to_clksel() and comment disagree with
the actual value returned on error.  Fix this to return the correct error
value.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-14 13:24:10 +00:00
Russell King
8b9dbc16d4 [ARM] omap: arrange for clock recalc methods to return the rate
linux-omap source commit 33d000c99ee393fe2042f93e8422f94976d276ce
introduces a way to "dry run" clock changes before they're committed.
However, this involves putting logic to handle this into each and
every recalc function, and unfortunately due to the caching, led to
some bugs.

Solve both of issues by making the recalc methods always return the
clock rate for the clock, which the caller decides what to do with.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-14 09:59:21 +00:00
Ingo Molnar
22796b1572 Merge branch 'core/header-fixes' into x86/headers
Conflicts:
	arch/x86/include/asm/setup.h
2009-02-13 21:05:03 +01:00
Ingo Molnar
8f8573ae9f Merge branches 'irq/genirq', 'irq/sparseirq' and 'irq/urgent' into irq/core 2009-02-13 11:57:18 +01:00
Ingo Molnar
f8a6b2b9ce Merge branch 'linus' into x86/apic
Conflicts:
	arch/x86/kernel/acpi/boot.c
	arch/x86/mm/fault.c
2009-02-13 09:44:22 +01:00
Catalin Marinas
2d7c11bfc9 [ARM] 5382/1: unwind: Reorganise the stacktrace support
This patch changes the walk_stacktrace and its callers for easier
integration of stack unwinding. The arch/arm/kernel/stacktrace.h file is
also moved to arch/arm/include/asm/stacktrace.h.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-12 13:21:17 +00:00
Catalin Marinas
67a94c23bb [ARM] 5381/1: unwind: Reorganise the traps.c code
This patch moves code around in the arch/arm/kernel/traps.c file for
easier integration of the stack unwinding support.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-12 13:21:15 +00:00
wanzongshun
a12370f12f [ARM] 5393/1: Add W90P910 EVB NOR flash driver
Add W90P910 Evaluate Board NOR flash driver support,
The EV Board default support W19B320ABT7H of Winbond inc.

Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-12 11:10:24 +00:00
wanzongshun
9ee8c9f012 [ARM] 5392/1: Delete redundant macros for w90p910
Delete the macros W90X900_RES and W90X900_DEVICE
I thought it will be better to define the structures
for each device directly.

Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-12 11:10:23 +00:00
Catalin Marinas
e9fc78230c [ARM] 5389/1: Make sure the pmd entries are visible by the secondary CPU
The __cpu_up() function in arch/arm/kernel/smp.c sets the pmd entries
without flushing or cleaning them.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-12 10:59:45 +00:00
Catalin Marinas
7279dc3e91 [ARM] 5388/1: Add hwcap bits for VFPv3 and VFPv3D16
The VFPv3D16 is a VFPv3 CPU configuration where only 16 double registers
are present, as the VFPv2 configuration. This patch adds the
corresponding hwcap bits so that applications or debuggers have more
information about the supported features.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-12 10:59:44 +00:00
Catalin Marinas
3d1228ead6 [ARM] 5387/1: Add ptrace VFP support on ARM
This patch adds ptrace support for setting and getting the VFP registers
using PTRACE_SETVFPREGS and PTRACE_GETVFPREGS. The user_vfp structure
defined in asm/user.h contains 32 double registers (to cover VFPv3 and
Neon hardware) and the FPSCR register.

Cc: Paul Brook <paul@codesourcery.com>
Cc: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-12 10:59:43 +00:00
Ryan Mallon
f373e8c063 [ARM] 5373/2: Add gpiolib support to AT91
Add support for gpiolib, including debugfs output, to the AT91 family.
The at91_get/set_gpio_value calls still exist since they are used by the
atmel serial driver.

Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-12 10:45:08 +00:00
Zbynek Michl
b7eb1a5ed5 [ARM] 5355/1: Adding support for the HTC Himalaya and its framebuffer
Patch adds support for the HTC Himalaya device. It includes hardware definitions and w100fb support.

Signed-off-by: Zbynek Michl <Zbynek.Michl@seznam.cz>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-10 11:29:41 +00:00
Jaya Kumar
4ce255c142 [ARM] 5354/1: mach-pxa: add AM300 platform driver v3
This patch adds support for the AM300 platform driver which uses the
E-Ink broadsheetfb display driver.

Cc: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-10 11:28:00 +00:00
Kristoffer Ericson
b4e411294a [ARM] 5375/1: PATCH - update jornada720.c to reflect driver additions
This patch updates the list of devices activated at init
to also include the keyboard and touchscreen structs.
We also remove a non-needed #ifdef.

Signed-off-by: Kristoffer Ericson <kristoffer.ericson@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-10 11:24:22 +00:00
wanzongshun
17198f2d68 [ARM] 5374/1: The w90p910 uart0 driver patch
Add W90P910 UART0 support,the W90P910 UART0 is 8250 series.

Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-10 11:24:21 +00:00
Daniel Silverstone
b74788d8c1 [ARM] 5372/1: ACS5K: Core board support for the ACS-5000
This patch provides the core board support for the Brivo Systems
LLC ACS-5000 master board for automated door/card-reader etc
management.

Signed-off-by: Daniel Silverstone <dsilvers@simtec.co.uk>
Signed-off-by: Vincent Sanders <vince@simtec.co.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-10 11:24:21 +00:00
Hartley Sweeten
93faee1d50 [ARM] 5371/1: ep93xx: add i2c device to edb9307a
Add the on-board rtc i2c device to the edb9307a platform init.

The EP93xx based EDB9307A dev board has an on-board ISL1208 RTC
connected to the I2C bus.  Now that the core code supports the
I2C bus, this patch will add support for the device.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-10 11:24:20 +00:00
Tobias Klauser
e0fc4f97ab [ARM] Storage class should be before const qualifier
The C99 specification states in section 6.11.5:

The placement of a storage-class specifier other than at the beginning of the
declaration specifiers in a declaration is an obsolescent feature.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-10 09:59:19 +00:00
Russell King
286ce0ac1c Merge branch 'fix' of git://git.kernel.org/pub/scm/linux/kernel/git/ycmiao/pxa-linux-2.6 2009-02-09 09:43:47 +00:00
Philipp Zabel
772885c1dc pxa/spitz: Setup I2S pins for pxa2xx-i2s
The spitz has a WM8750 codec connected as I2S slave but doesn't use the
PXA I2S system clock.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Acked-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-02-08 20:40:25 +00:00
Philipp Zabel
4e7f78f815 pxa/h5000: Setup I2S pins for pxa2xx-i2s
The iPAQ h5000 has an AK4535 codec connected as I2S slave,
PXA I2S providing SYSCLK.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Acked-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-02-08 20:40:25 +00:00
Paul Walmsley
883992bd8f [ARM] OMAP2/3 clock: don't tinker with hardirqs when they are supposed to be disabled
Clock rate change code executes inside a spinlock with hardirqs
disabled.  The only code that should be messing around with the
hardirq state should be the plat-omap/clock.c code.  In the
omap2_reprogram_dpllcore() case, this probably just wastes cycles, but
in the omap3_core_dpll_m2_set_rate() case, this is a nasty bug.

linux-omap source commit is b9b6208dadb5e0d8b290900a3ffa911673ca97ed.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-08 17:50:47 +00:00
Russell King
8263e5b31e [ARM] omap: fix clockdomain enable/disable ordering
Based on a patch from Paul Walmsley <paul@pwsan.com>:

 omap2_clk_enable() should enable a clock's clockdomain before
 attempting to enable its parent clock's clockdomain.  Similarly, in
 the unlikely event that the parent clock enable fails, the clockdomain
 should be disabled.

 linux-omap source commit is 6d6e285e5a7912b1ea68fadac387304c914aaba8.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-08 17:50:46 +00:00
Russell King
a7f8c599c5 [ARM] omap: fix usecount decrement bug
Based upon a patch from Paul Walmsley <paul@pwsan.com>:

 If _omap2_clk_enable() fails, the clock's usecount must be decremented
 by one no matter whether the clock has a parent or not.

but reorganised a bit.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-08 17:50:46 +00:00
Paul Walmsley
be5f34b773 [ARM] OMAP clock: drop clk_get_usecount()
This function is race-prone and mistakenly conveys the impression to
drivers that it is part of the clock interface.  Get rid of it: core
code that absolutely needs this can just check clk->usecount.  Drivers
should not use it at all.

linux-omap source commit is 5df9e4adc2f6a6d55aca53ee27b8baad18897c05.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-08 17:50:45 +00:00
Paul Walmsley
f11fda6a91 [ARM] OMAP2/3 clock: convert remaining MPU barriers into OCP barriers
Several parts of the OMAP2/3 clock code use wmb() to try to ensure
that the hardware write completes before continuing.  This approach is
problematic: wmb() only ensures that the write leaves the ARM.  It
does not ensure that the write actually reaches the endpoint device.
The endpoint device in this case - either the PRM, CM, or SCM - is
three interconnects away from the ARM - and the final interconnect is
low-speed.  And the OCP interconnects will post the write, and who
knows how long that will take to complete.  So the wmb() is not what
we want.  Worse, the wmb() is indiscriminate; it causes the ARM to
flush any other unrelated buffered writes and wait for the local
interconnect to acknowledge them - potentially very expensive.

Fix this by converting the wmb()s into readbacks of the same PRM/CM/SCM
register.  Since the PRM/CM/SCM devices use a single OCP thread, this
will cause the MPU to block while waiting for posted writes to that device
to complete.

linux-omap source commit is 260f5487848681b4d8ea7430a709a601bbcb21d1.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-08 17:50:45 +00:00
Paul Walmsley
439764cc18 [ARM] OMAP2xxx clock: consolidate DELAYED_APP clock commits; fix barrier
Consolidate the commit code for DELAYED_APP clocks into a subroutine,
_omap2xxx_clk_commit().  Also convert the MPU barrier wmb() into an
OCP barrier, since with an MPU barrier, we have no guarantee that the
write actually reached the endpoint device.

linux-omap source commit is 0f5bdb736515801b296125d16937a21ff7b3cfdc.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-08 17:50:44 +00:00
Paul Walmsley
de07fedd79 [ARM] OMAP2/3 clock: don't use a barrier after clk_disable()
clk_disable() previously used an ARM barrier, wmb(), to try to ensure
that the hardware write completed before continuing.  There are some
problems with this approach.

The first problem is that wmb() only ensures that the write leaves the
ARM -- not that it actually reaches the endpoint device.  In this
case, the endpoint device - either the PRM, CM, or SCM - is three
interconnects away from the ARM, and the final interconnect is
low-speed.  And the OCP interconnects will post the write, who knows
how long that will take to complete.  So the wmb() is not really what
we want.

Worse, the wmb() is indiscriminate; it will cause the ARM to flush any
other unrelated buffered writes and wait for the local interconnect to
acknowledge them - potentially very expensive.

This first problem could be fixed by doing a readback of the same PRM/CM/SCM
register.  Since these devices use a single OCP thread, this will cause the
MPU to wait for the write to complete.

But the primary problem is a conceptual one: clk_disable() should not
need any kind of barrier.  clk_enable() needs one since device driver
code must not access a device until its clocks are known to be
enabled.  But clk_disable() has no such restriction.

Since blocking the MPU on a PRM/CM/SCM write can be a very
high-latency operation - several hundred MPU cycles - it's worth
avoiding this barrier if possible.

linux-omap source commit is f4aacad2c0ed1055622d5c1e910befece24ef0e2.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-08 17:50:42 +00:00