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Only the basic to aid debugging.
Usage:
echo <cpuid>,<clusterid> > /dev/b.L_switcher
where <cpuid> is between 0 and 3, and <clusterid> is 0 for the
A15 cluster and 1 for the A7 cluster.
Signed-off-by: nicolas Pitre <nico@linaro.org>
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The main entry point for a switch request is:
void bL_switch_request(unsigned int cpu, unsigned int new_cluster_id)
If the calling CPU is not the wanted one, this wrapper takes care of
sending the request to the appropriate CPU with schedule_work_on().
In the future, some switching related tasks which do not require a
strict CPU affinity might be moved here though.
At the moment the core switch operation is handled by bL_switch_to()
which must be called on the CPU for which a switch is requested.
What this code does:
* Return early if the current cluster is the wanted one.
* Close the gate in the kernel entry vector for both the inbound
and outbound CPUs.
* Wake up the inbound CPU so it can perform its reset sequence in
parallel up to the kernel entry vector gate.
* Migrate all interrupts in the GIC targeting the outbound CPU
interface to the inbound CPU interface, including SGIs. This is
performed by gic_migrate_target() in arch/arm/common/gic.c.
* Shut down the local timer for the outbound CPU.
* Call cpu_pm_enter() which takes care of flushing the VFP state to
RAM and save the CPU interface config from the GIC to RAM.
* Call cpu_suspend() which saves the CPU state (general purpose
registers, page table address) onto the stack and store the
resulting stack pointer in an array indexed by processor number,
then call the provided shutdown function. This happens in
arch/arm/kernel/sleep.S.
At this point, the provided shutdown function executed by the outbound
CPU ungates the inbound CPU. Therefore the inbound CPU:
* Picks up the saved stack pointer in the array indexed by
processor number above. At the moment the corresponding code in
arch/arm/kernel/sleep.S only looks at the CPU number field in the
MPIDR so the current code works unmodified even if the new CPU
comes from a different cluster.
* The MMU and caches are re-enabled using the saved state on the
provided stack, just like if this was a resume operation from a
suspended state.
* Then cpu_suspend() returns, although this is on the inbound CPU
rather than the outbound CPU which called it initially.
* The function cpu_pm_exit() is called which effect is to restore the
CPU interface state in the GIC using the state previously saved by
the outbound CPU.
* The local timer on the inbound CPU is restored.
* Exit of bL_switch_to() to resume normal kernel execution on the
new CPU.
However, the outbound CPU is potentially still running in parallel while
the inbound CPU is resuming normal kernel execution, hence we need
per CPU stack isolation to execute bL_do_switch(). After the outbound
CPU has ungated the inbound CPU, it calls bL_cpu_power_down() to:
* Clean its L1 cache.
* If it is the last CPU still alive in its cluster (last man standing),
it also cleans its L2 cache and disables cache snooping from the other
cluster.
Code called from bL_do_switch() might end up referencing 'current' for
some reasons. However, 'current' is derived from the stack pointer.
With any arbitrary stack, the returned value for 'current' and any
dereferenced values through it are just random garbage which may lead to
segmentation faults.
The active page table during the execution of bL_do_switch() is also a
problem. There is no guarantee that the inbound CPU won't destroy the
corresponding task which would free the attached page table while the
outbound CPU is still running and relying on it.
To solve both issues, we borrow some of the task space belonging to
the init/idle task which, by its nature, is lightly used and therefore
is unlikely to clash with our usage. The init task is also never going
away.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
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The full mcpm layer is not likely to be relevant to v6 based
platforms, so a multiplatform kernel won't use that code if booted
on v6 hardware.
This patch modifies the AFLAGS for affected mcpm .S files to
specify armv7-a explicitly for that code.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Now that the cluster power API is in place, we can use it for SMP secondary
bringup and CPU hotplug in a generic fashion.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
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Instead of requiring the first man to be elected in advance (which
can be suboptimal in some situations), this patch uses a per-
cluster mutex to co-ordinate selection of the first man.
This should also make it more feasible to reuse this code path for
asynchronous cluster resume (as in CPUidle scenarios).
We must ensure that the vlock data doesn't share a cacheline with
anything else, or dirty cache eviction could corrupt it.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
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CPUs in cluster based systems, such as big.LITTLE, have special needs
when entering the kernel due to a hotplug event, or when resuming from
a deep sleep mode.
This is vectorized so multiple CPUs can enter the kernel in parallel
without serialization.
The mcpm prefix stands for "multi cluster power management", however
this is usable on single cluster systems as well. Only the basic
structure is introduced here. This will be extended with later patches.
In order not to complexify things more than they currently have to,
the planned work to make runtime adjusted MPIDR based indexing and
dynamic memory allocation for cluster states is postponed to a later
cycle. The MAX_NR_CLUSTERS and MAX_CPUS_PER_CLUSTER static definitions
should be sufficient for those systems expected to be available in the
near future.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
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Now that we have drivers/irqchip, move VIC irqchip to drivers/irqchip.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
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Now that we have drivers/irqchip, move GIC irqchip to drivers/irqchip. This
is necessary to share the GIC with arm and arm64.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
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ixp2xxx platforms have had no real changes since ~2006 and the maintainer
has said on irc that they can be removed:
13:05 < nico> do you still care about ixp2000?
13:22 < lennert> not really, no
13:58 < nico> do you think we could remove it from the kernel tree?
14:01 < lennert> go for it, and remove ixp23xx too while you're at it
Removing will help simplify ARM consolidation in general and PCI re-work
specifically.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Lennert Buytenhek <buytenh@wantstofly.org>
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Pull slave-dmaengine update from Vinod Koul:
"This includes the cookie cleanup by Russell, the addition of context
parameter for dmaengine APIs, more arm dmaengine driver cleanup by
moving code to dmaengine, this time for imx by Javier and pl330 by
Boojin along with the usual driver fixes."
Fix up some fairly trivial conflicts with various other cleanups.
* 'next' of git://git.infradead.org/users/vkoul/slave-dma: (67 commits)
dmaengine: imx: fix the build failure on x86_64
dmaengine: i.MX: Fix merge of cookie branch.
dmaengine: i.MX: Add support for interleaved transfers.
dmaengine: imx-dma: use 'dev_dbg' and 'dev_warn' for messages.
dmaengine: imx-dma: remove 'imx_dmav1_baseaddr' and 'dma_clk'.
dmaengine: imx-dma: remove unused arg of imxdma_sg_next.
dmaengine: imx-dma: remove internal structure.
dmaengine: imx-dma: remove 'resbytes' field of 'internal' structure.
dmaengine: imx-dma: remove 'in_use' field of 'internal' structure.
dmaengine: imx-dma: remove sg member from internal structure.
dmaengine: imx-dma: remove 'imxdma_setup_sg_hw' function.
dmaengine: imx-dma: remove 'imxdma_config_channel_hw' function.
dmaengine: imx-dma: remove 'imxdma_setup_mem2mem_hw' function.
dmaengine: imx-dma: remove dma_mode member of internal structure.
dmaengine: imx-dma: remove data member from internal structure.
dmaengine: imx-dma: merge old dma-v1.c with imx-dma.c
dmaengine: at_hdmac: add slave config operation
dmaengine: add context parameter to prep_slave_sg and prep_dma_cyclic
dmaengine/dma_slave: introduce inline wrappers
dma: imx-sdma: Treat firmware messages as warnings instead of erros
...
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Nothing but RiscPC makes use of the Acorn timekeeping code, so move
it into mach-rpc.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Currently there were two part of DMAC PL330 driver for
support old styled s3c-pl330 which has been merged into
drivers/dma/pl330.c driver. Actually, there is no reason
to separate them now.
Basically this patch merges arch/arm/common/pl330.c into
drivers/dma/pl330.c driver and removes useless exported
symbol, externed function and so on.
The newer pl330 driver tested on SMDKV310 and SMDK4212 boards
Cc: Jassi Brar <jassisinghbrar@gmail.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Boojin Kim <boojin.kim@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
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The patch below removes an unused config variable found by using a kernel
cleanup script.
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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From: Rob Herring <rob.herring@smooth-stone.com>
The timer-sp h/w used on versatile platforms can also be used for other
platforms, so move it to a common location.
Signed-off-by: Rob Herring <rob.herring@smooth-stone.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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'omap', 'pxa', 'spear' and 'versatile' into devel
Conflicts:
arch/arm/Makefile
arch/arm/common/Makefile
arch/arm/mm/Kconfig
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PL330 is a configurable DMA controller PrimeCell device.
The register map of the device is well defined.
The configuration of a particular implementation can be
read from the six configuration registers CR0-4,Dn.
This patch implements a driver for the specification:-
http://infocenter.arm.com/help/topic/com.arm.doc.ddi0424a/DDI0424A_dmac_pl330_r0p0_trm.pdf
The exported interface should be sufficient to implement
a driver for any DMA API.
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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The only difference between ICST307 and ICST525 are the two arrays
for calculating the S parameter; the code is now identical. Merge
the two files and kill the duplicated code.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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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>
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Add some generic infrastructure to assist looking up struct clks
for the ARM architecture.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Now that all drivers using it are gone, remove the old ARM RTC library.
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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This patch provides driver for ITE 8152 PCI bridge.
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Patch from Lennert Buytenhek
This patch allows the ixp2000 uengine loader that is already in the
tree to also be used on the ixp23xx.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Patch from Lennert Buytenhek
Move the uengine loader from arch/arm/mach-ixp2000 to arch/arm/common
so that ixp23xx can use it too.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Other machines may wish to make use of the VIC support code, so
move it to arch/arm/common.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Make the AMBA bus code visible to other architectures.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Patch from Richard Purdie
This patch moves a large chunk of the sharpsl_pm driver to
arch/arm/common so that it can be reused on other devices such as the
SL-5500 (collie). It also abstracts some functions from the core into
the machine and platform specific parts of the driver to aid reuse.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Add support for the ARM Generic Interrupt Controller.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
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