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Freescale updates from Scott. Mostly support for critical
and machine check exceptions on 64-bit BookE, some new
PCI suspend/resume work and misc bits.
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While checking powersaving mode in machine check handler at 0x200, we
clobber CFAR register. Fix it by saving and restoring it during beq/bgt.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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I noticed this when testing setarch. No, we don't magically
support a big endian userspace on a little endian kernel.
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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The ppc_rtas() syscall allows userspace to interact directly with RTAS.
For the moment, it assumes every thing is big endian and returns either
EINVAL or EFAULT when called in a little endian environment.
As suggested by Benjamin, to avoid bugs when userspace wants to pass
a non 32 bit value to RTAS, it is far better to stick with a simple
rationale: ppc_rtas() should be called with a big endian rtas_args
structure.
With this patch, it is now up to userspace to forge big endian arguments,
as expected by RTAS.
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Our netfilter options are stale and important things like masquerading
are no longer enabled. Instead of trying to keep up with any updates,
set CONFIG_NETFILTER_ADVANCED=n on ppc64* and pseries* defconfigs.
This enables the most common netfilter modules for us.
While here, enable the network bridge module which is heavily used in
KVM setups.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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We also set it to be enabled always. This helps in wider testing
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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We have generic code like the one in get_futex_key that assume that
a local_irq_disable prevents a parallel THP split. Support that by
adding a dummy smp call function after setting _PAGE_SPLITTING. Code
paths like get_user_pages_fast still need to check for _PAGE_SPLITTING
after disabling IRQ which indicate that a parallel THP splitting is
ongoing. Now if they don't find _PAGE_SPLITTING set, then we can be
sure that parallel split will now block in pmdp_splitting flush
until we enables IRQ
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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The facility unavailable exception can be triggered from userspace by
accessing PMU registers when EBB is not enabled. This causes the
included pr_err() to run, hence spamming the kernel log buffer.
This avoids this by rate limiting these messages.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Currently we reject events which have the L3 bank == 1, such as
0x000084918F, because the cache field is non-zero.
However that is incorrect, because although the bank is non-zero, the
value we would write into MMCRC is zero, and so we can count the event.
So fix the check to ignore the bank selector when checking whether the
cache selector is non-zero.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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The commit adds a Kconfig option which allows the hv_gpci and hv_24x7
PMUs, added in the preceeding commits, to be built.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This provides a basic interface between hv_24x7 and perf. Similar to
the one provided for gpci, it lacks transaction support and does not
list any events.
Example usage via perf tool:
perf stat -e 'hv_24x7/domain=2,offset=8,starting_index=0,lpar=0xffffffff/' -r 0 -C 0 -x ' ' sleep 0.1
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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interface
This provides a basic link between perf and hv_gpci. Notably, it does
not yet support transactions and does not list any events (they can
still be manually composed).
Example usage via perf tool:
perf stat -e 'hv_gpci/counter_info_version=3,offset=0,length=8,secondary_index=0,starting_index=0xffffffff,request=0x10/' -r 0 -C 0 -x ' ' sleep 0.1
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Add two macros which generate functions to extract the relevent bits
from event->attr.config{,1,2}.
EVENT_DEFINE_RANGE() defines an accessor for a range of bits in the
event, as well as a "max" function that gives the maximum value of the
field based on the bit width.
EVENT_DEFINE_RANGE_FORMAT() defines the accessor & max routine and also
a format attribute for use in the PMU's attr_groups.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
[mpe: move to powerpc, ugly but descriptive macro names]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This exposes a simple way to grab the firmware provided
collect_priveliged, ga, expanded, and lab capability bits. All of these
bits come in from the same gpci request, so we've exposed all of them.
Only the collect_priveliged bit is really used by the hv-gpci/hv-24x7
code, the other bits are simply exposed in sysfs to inform the user.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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24x7 (also called hv_24x7 or H_24X7) is an interface to obtain
performance counters from the hypervisor. These counters do not have a
fixed format/possition and are instead documented in a "24x7 Catalog",
which is provided by the hypervisor (that interface is also documented
paritialy in the included hv-24x7-catalog.h and fully in at
https://raw.githubusercontent.com/jmesmon/catalog-24x7/master/hv-24x7-catalog.h ).
The 24x7 data access is simply a copy operation into a 4 dimentional
array of 64bit counters (from hypervisor to kernel memory). There is no
interupt triggered on overflow, these are completely disjoint from the
typical power pmu.
This method of obtaining performance counters from the hypervisor is
intended to paritialy replace the gpci interface.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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"H_GetPerformanceCounterInfo" (refered to as hv_gpci or just gpci from
here on) is an interface to retrieve specific performance counters and
other data from the hypervisor. All outputs have a fixed format. This
header only describes the portions of the interface that we plan on
using in linux at this time.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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The previous commit added constraint and register handling to allow
processes using EBB (Event Based Branches) to request access to the BHRB
(Branch History Rolling Buffer).
With that in place we can allow processes using EBB to access the BHRB.
This is achieved by setting BHRBA in MMCR0 when we enable EBB access. We
must also clear BHRBA when we are disabling.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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We want a way for users of EBB (Event Based Branches) to also access the
BHRB (Branch History Rolling Buffer). EBB does not interoperate with our
existing BHRB support, which is wired into the generic Linux branch
stack sampling support.
To support EBB & BHRB we add three new bits to the event code. The first
bit indicates that the event wants access to the BHRB, and the other two
bits indicate the desired IFM (Instruction Filtering Mode).
We allow multiple events to request access to the BHRB, but they must
agree on the IFM value. Events which are not interested in the BHRB can
also interoperate with events which do.
Finally we program the desired IFM value into MMCRA. Although we do this
for every event, we know that the value will be identical for all events
that request BHRB access.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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We only need to mask the EBB bit out of the event for the check of the
special PMC 5 & 6 events. So use a local to do it just for that code,
rather than changing the event value for the life of the function.
While we're there move the set of mask and value after all the checks.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Rather than using PERF_EVENT_CONFIG_EBB_SHIFT everywhere, add an
EVENT_EBB_SHIFT like every other event and use that.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Although we already block EBB events which request sampling using
sample_period, technically it's possible for an event to set sample_type
but not sample_period.
Nothing terrible will happen if an EBB event does specify sample_type,
but it signals a major confusion on the part of userspace, and so we do
them the favor of rejecting it.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Some power8 revisions have a hardware bug where we can lose a PMU
exception, this commit adds a workaround to detect the bad condition and
rectify the situation.
See the comment in the commit for a full description.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Some power8 revisions have a hardware bug where we can lose a
Performance Monitor (PMU) exception under certain circumstances.
We will be adding a workaround for this case, see the next commit for
details. The observed behaviour is that writing PMAO doesn't cause an
exception as we would expect, hence the name of the feature.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Currently the sysrq ShowRegs command does not print any PMU registers as
we have an empty definition for perf_event_print_debug(). This patch
defines perf_event_print_debug() to print various PMU registers.
Example output:
CPU: 0 PMU registers, ppmu = POWER7 n_counters = 6
PMC1: 00000000 PMC2: 00000000 PMC3: 00000000 PMC4: 00000000
PMC5: 00000000 PMC6: 00000000 PMC7: deadbeef PMC8: deadbeef
MMCR0: 0000000080000000 MMCR1: 0000000000000000 MMCRA: 0f00000001000000
SIAR: 0000000000000000 SDAR: 0000000000000000 SIER: 0000000000000000
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
[mpe: Fix 32 bit build and rework formatting for compactness]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This patchset adds some missing event list for POWER7 PMU raw
events which are exported through sysfs interface. Also updates
the ABI documentation to add all the sysfs exported raw events.
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This patch enables fetching of various platform sensor data through
OPAL and expects a sensor handle from the driver to pass to OPAL.
Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This patch enables reading and updating of system parameters through
OPAL call.
Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This patch adds support for notifying the clients of their request
completion. Clients request for the token before making OPAL call
and then wait for the response.
This patch uses messaging infrastructure to pull the data to linux
by registering itself for the message type OPAL_MSG_ASYNC_COMP.
Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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If we do nothing in suspend/resume, some platform PCIe ip-block
can't guarantee the link back to L0 state from sleep, then, when
we read the EP device will hang. Only we send pme turnoff message
in pci controller suspend, and send pme exit message in resume, the
link state will be normal.
When we send pme turnoff message in pci controller suspend, the
links will into l2/l3 ready, then, host cannot communicate with
ep device, but pci-driver will call back EP device to save them
state. So we need to change platform_driver->suspend/resume to
syscore->suspend/resume.
So the new suspend/resume implementation, send pme turnoff message
in suspend, and send pme exit message in resume. And add a PME handler,
to response PME & message interrupt.
Change platform_driver->suspend/resume to syscore->suspend/resume.
pci-driver will call back EP device, to save EP state in
pci_pm_suspend_noirq, so we need to keep the link, until
pci_pm_suspend_noirq finish.
Signed-off-by: Wang Dongsheng <dongsheng.wang@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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Add special state saving for critical and machine check exceptions.
Most of this code could be used to handle debug exceptions taken from
kernel space, but actually doing so is outside the scope of this patch.
The various critical and machine check exceptions now point to their
real handlers, rather than hanging the kernel.
Signed-off-by: Scott Wood <scottwood@freescale.com>
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Use the proper scratch SPRG and PACA region. Introduce level-specific
macros to simplify usage and avoid needing to do a bunch of token
pasting throughout EXCEPTION_COMMON().
Now that EXCEPTION_COMMON_DBG() is properly using the debug scratch
register, there's no more need for the caller to move the value to the
GEN scratch first.
Signed-off-by: Scott Wood <scottwood@freescale.com>
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The ints parameter was used to optionally insert RECONCILE_IRQ_STATE
into EXCEPTION_COMMON. However, since it came at the end of
EXCEPTION_COMMON, there was no real benefit for it to be there as
opposed to being called separately by the caller of EXCEPTION_COMMON.
The ints parameter was causing some hassle when trying to add an extra
macro layer. Besides avoiding that, moving "ints" to the caller makes
the code simpler by:
- avoiding the asymmetry where INTS_RESTORE_HARD is called separately
by the individual exception, but INTS_DISABLE was not
- removing the no-op INTS_KEEP
- not having an unnecessary macro parameter
It also turned out to be necessary to delay the INTS_DISABLE
in the case of special level exceptions until after we saved the
old value of PACAIRQHAPPENED.
Signed-off-by: Scott Wood <scottwood@freescale.com>
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While bolted handlers (including e6500) do not need to deal with a TLB
miss recursively causing another TLB miss, nested TLB misses can still
happen with crit/mc/debug exceptions -- so we still need to honor
SPRG_TLB_EXFRAME.
We don't need to spend time modifying it in the TLB miss fastpath,
though -- the special level exception will handle that.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>
Cc: kvm-ppc@vger.kernel.org
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Previously SPRG3 was marked for use by both VDSO and critical
interrupts (though critical interrupts were not fully implemented).
In commit 8b64a9dfb091f1eca8b7e58da82f1e7d1d5fe0ad ("powerpc/booke64:
Use SPRG0/3 scratch for bolted TLB miss & crit int"), Mihai Caraman
made an attempt to resolve this conflict by restoring the VDSO value
early in the critical interrupt, but this has some issues:
- It's incompatible with EXCEPTION_COMMON which restores r13 from the
by-then-overwritten scratch (this cost me some debugging time).
- It forces critical exceptions to be a special case handled
differently from even machine check and debug level exceptions.
- It didn't occur to me that it was possible to make this work at all
(by doing a final "ld r13, PACA_EXCRIT+EX_R13(r13)") until after
I made (most of) this patch. :-)
It might be worth investigating using a load rather than SPRG on return
from all exceptions (except TLB misses where the scratch never leaves
the SPRG) -- it could save a few cycles. Until then, let's stick with
SPRG for all exceptions.
Since we cannot use SPRG4-7 for scratch without corrupting the state of
a KVM guest, move VDSO to SPRG7 on book3e. Since neither SPRG4-7 nor
critical interrupts exist on book3s, SPRG3 is still used for VDSO
there.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: kvm-ppc@vger.kernel.org
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Once special level interrupts are supported, we may take nested TLB
misses -- so allow the same thread to acquire the lock recursively.
The lock will not be effective against the nested TLB miss handler
trying to write the same entry as the interrupted TLB miss handler, but
that's also a problem on non-threaded CPUs that lack TLB write
conditional. This will be addressed in the patch that enables crit/mc
support by invalidating the TLB on return from level exceptions.
Signed-off-by: Scott Wood <scottwood@freescale.com>
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altivec_unavailable was commented as 0xf20 but the code uses 0x200.
Note that 0xf20 is also used by ap_unavailable.
altivec_assist was commented as 0x1700 but the code uses 0x220.
critical_input was commented as 0x580 but the code uses 0x100.
machine_check was commented and implemented as 0x200, which conflicts
with altivec_assist (it only builds because MC_EXCEPTION_PROLOG is
commented out). Changed to the fixed IVOR value of 0x000.
Signed-off-by: Scott Wood <scottwood@freescale.com>
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We need to store thread info to these exception thread info like something
we already did for PPC32.
Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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We already allocated critical/machine/debug check exceptions, but
we also should initialize those associated kernel stack pointers
for use by special exceptions in the PACA.
Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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Signed-off-by: Wang Dongsheng <dongsheng.wang@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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There is QE on platform T104x, add support.
Call funcs qe_ic_init and qe_init if CONFIG_QUICC_ENGINE is defined.
Signed-off-by: Zhao Qiang <B45475@freescale.com>
[scottwood@freesacle.com: whitespace fix]
Signed-off-by: Scott Wood <scottwood@freescale.com>
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New QE doesn't have par_io, it doesn't need to init par_io
for new QE.
Split function mpc85xx_qe_init() into mpc85xx_qe_init()
and mpc85xx_qe_par_io_init().
Call mpc85xx_qe_init() for both new and old while
mpc85xx_qe_par_io_init() after mpc85xx_qe_init() for old.
Signed-off-by: Zhao Qiang <B45475@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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If CONFIG_UCC_GETH or CONFIG_SERIAL_QE is not defined then we get a
warning about an used variable which leads to a build error.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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CONFIG_FSL_IFC gets enabled by Kconfig dependancies.
So remove unnecssary define from the defconfigs
Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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Add power sensor chip ina220 node in dts to support
power monitor
Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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The MPC7448HPC2 and PPC_HOLLY config options contain TSI108_BRIDGE
duplicates since commit:
commit 3490cba56f7f8a78ef4c94814c3181f09ce1e2ef
Author: Jon Loeliger <jdl@jdl.com>
Date: Wed Jan 23 12:42:50 2008 -0600
[POWERPC] Add initial iomega StorCenter board port.
This patch cleans these duplicates.
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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For PEXCSRBAR, bit 3-0 indicate prefetchable and address type.
So when getting base address, these bits should be masked,
otherwise we may get incorrect base address.
Signed-off-by: Minghuan Lian <Minghuan.Lian@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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The following SoCs will be affected: p2041, p3041, p4080,
p5020, p5040, b4420, b4860, t4240
Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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This enables support for userspace to fetch and initiate FSP and
Platform dumps from the service processor (via firmware) through sysfs.
Based on original patch from Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Flow:
- We register for OPAL notification events.
- OPAL sends new dump available notification.
- We make information on dump available via sysfs
- Userspace requests dump contents
- We retrieve the dump via OPAL interface
- User copies the dump data
- userspace sends ack for dump
- We send ACK to OPAL.
sysfs files:
- We add the /sys/firmware/opal/dump directory
- echoing 1 (well, anything, but in future we may support
different dump types) to /sys/firmware/opal/dump/initiate_dump
will initiate a dump.
- Each dump that we've been notified of gets a directory
in /sys/firmware/opal/dump/ with a name of the dump type and ID (in hex,
as this is what's used elsewhere to identify the dump).
- Each dump has files: id, type, dump and acknowledge
dump is binary and is the dump itself.
echoing 'ack' to acknowledge (currently any string will do) will
acknowledge the dump and it will soon after disappear from sysfs.
OPAL APIs:
- opal_dump_init()
- opal_dump_info()
- opal_dump_read()
- opal_dump_ack()
- opal_dump_resend_notification()
Currently we are only ever notified for one dump at a time (until
the user explicitly acks the current dump, then we get a notification
of the next dump), but this kernel code should "just work" when OPAL
starts notifying us of all the dumps present.
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Based on a patch by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
This patch adds support to read error logs from OPAL and export
them to userspace through a sysfs interface.
We export each log entry as a directory in /sys/firmware/opal/elog/
Currently, OPAL will buffer up to 128 error log records, we don't
need to have any knowledge of this limit on the Linux side as that
is actually largely transparent to us.
Each error log entry has the following files: id, type, acknowledge, raw.
Currently we just export the raw binary error log in the 'raw' attribute.
In a future patch, we may parse more of the error log to make it a bit
easier for userspace (e.g. to be able to display a brief summary in
petitboot without having to have a full parser).
If we have >128 logs from OPAL, we'll only be notified of 128 until
userspace starts acknowledging them. This limitation may be lifted in
the future and with this patch, that should "just work" from the linux side.
A userspace daemon should:
- wait for error log entries using normal mechanisms (we announce creation)
- read error log entry
- save error log entry safely to disk
- acknowledge the error log entry
- rinse, repeat.
On the Linux side, we read the error log when we're notified of it. This
possibly isn't ideal as it would be better to only read them on-demand.
However, this doesn't really work with current OPAL interface, so we
read the error log immediately when notified at the moment.
I've tested this pretty extensively and am rather confident that the
linux side of things works rather well. There is currently an issue with
the service processor side of things for >128 error logs though.
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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