Make trylock code common regardless of ticket size.
(Also, rename arch_spinlock.slock to head_tail.)
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Convert the two variants of __ticket_spin_lock() to use xadd(), which
has the effect of making them identical, so remove the duplicate function.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The inner loop of __ticket_spin_lock isn't doing anything very special,
so reimplement it in C.
For the 8 bit ticket lock variant, we use a register union to get direct
access to the lower and upper bytes in the tickets, but unfortunately gcc
won't generate a direct comparison between the two halves of the register,
so the generated asm isn't quite as pretty as the hand-coded version.
However benchmarking shows that this is actually a small improvement in
runtime performance on some benchmarks, and never a slowdown.
We also need to make sure there's a barrier at the end of the lock loop
to make sure that the compiler doesn't move any instructions from within
the locked region into the region where we don't yet own the lock.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
A few cleanups to the way spinlocks are defined and accessed:
- define __ticket_t which is the size of a spinlock ticket (ie, enough
bits to hold all the cpus)
- Define struct arch_spinlock as a union containing plain slock and
the head and tail tickets
- Use head and tail to implement some of the spinlock predicates.
- Make all ticket variables unsigned.
- Use TICKET_SHIFT to form constants
Most of this will be used in later patches.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This covers the trivial cases from open-coded xadd to the xadd macros.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Add a common xadd implementation.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Everything that's actually common between 32 and 64-bit is moved into
cmpxchg.h.
xchg/cmpxchg will fail with a link error if they're passed an
unsupported size (which includes 64-bit args on 32-bit systems).
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Reduce arbitrary differences between 32 and 64 bits.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The nfsservctl system call is now gone, so we should remove all
linkage for it.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
According to the SFI specification irq number 0xFF means device has no
interrupt or interrupt attached via GPIO.
Currently, we don't handle this special case and set irq field in
*_board_info structs to 255. It leads to confusion in some drivers.
Accelerometer driver tries to register interrupt 255, fails and prints
"Cannot get IRQ" to dmesg.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
entry_32.S contained a hardcoded alternative instruction entry, and the
format changed in commit 59e97e4d6f ("x86: Make alternative
instruction pointers relative").
Replace the hardcoded entry with the altinstruction_entry macro. This
fixes the 32-bit boot with CONFIG_X86_INVD_BUG=y.
Reported-and-tested-by: Arnaud Lacombe <lacombar@gmail.com>
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While removing custom rendezvous code and switching to stop_machine,
commit 192d885742 ("x86, mtrr: use stop_machine APIs for doing MTRR
rendezvous") completely dropped mtrr setting code on !CONFIG_SMP
breaking MTRR settting on UP.
Fix it by removing the incorrect CONFIG_SMP.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Anders Eriksson <aeriksson@fastmail.fm>
Tested-and-acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86-32, vdso: On system call restart after SYSENTER, use int $0x80
x86, UV: Remove UV delay in starting slave cpus
x86, olpc: Wait for last byte of EC command to be accepted
When we enter a 32-bit system call via SYSENTER or SYSCALL, we shuffle
the arguments to match the int $0x80 calling convention. This was
probably a design mistake, but it's what it is now. This causes
errors if the system call as to be restarted.
For SYSENTER, we have to invoke the instruction from the vdso as the
return address is hardcoded. Accordingly, we can simply replace the
jump in the vdso with an int $0x80 instruction and use the slower
entry point for a post-restart.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/CA%2B55aFztZ=r5wa0x26KJQxvZOaQq8s2v3u50wCyJcA-Sc4g8gQ@mail.gmail.com
Cc: <stable@kernel.org>
* 'stable/bug.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen/tracing: Fix tracing config option properly
xen: Do not enable PV IPIs when vector callback not present
xen/x86: replace order-based range checking of M2P table by linear one
xen: xen-selfballoon.c needs more header files
Steven Rostedt says we should use CONFIG_EVENT_TRACING.
Cc:Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Fix regression for HVM case on older (<4.1.1) hypervisors caused by
commit 99bbb3a84a
Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Date: Thu Dec 2 17:55:10 2010 +0000
xen: PV on HVM: support PV spinlocks and IPIs
This change replaced the SMP operations with event based handlers without
taking into account that this only works when the hypervisor supports
callback vectors. This causes unexplainable hangs early on boot for
HVM guests with more than one CPU.
BugLink: http://bugs.launchpad.net/bugs/791850
CC: stable@kernel.org
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Tested-and-Reported-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
PCI: OF: Don't crash when bridge parent is NULL.
PCI: export pcie_bus_configure_settings symbol
PCI: code and comments cleanup
PCI: make cardbus-bridge resources optional
PCI: make SRIOV resources optional
PCI : ability to relocate assigned pci-resources
PCI: honor child buses add_size in hot plug configuration
PCI: Set PCI-E Max Payload Size on fabric
The order-based approach is not only less efficient (requiring a shift
and a compare, typical generated code looking like this
mov eax, [machine_to_phys_order]
mov ecx, eax
shr ebx, cl
test ebx, ebx
jnz ...
whereas a direct check requires just a compare, like in
cmp ebx, [machine_to_phys_nr]
jae ...
), but also slightly dangerous in the 32-on-64 case - the element
address calculation can wrap if the next power of two boundary is
sufficiently far away from the actual upper limit of the table, and
hence can result in user space addresses being accessed (with it being
unknown what may actually be mapped there).
Additionally, the elimination of the mistaken use of fls() here (should
have been __fls()) fixes a latent issue on x86-64 that would trigger
if the code was run on a system with memory extending beyond the 44-bit
boundary.
CC: stable@kernel.org
Signed-off-by: Jan Beulich <jbeulich@novell.com>
[v1: Based on Jeremy's feedback]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CONFIG_TASKSTATS just had a change to use netlink, including
a change to "depends on NET". Since "select" does not follow
dependencies, KVM also needs to depend on NET to prevent build
errors when CONFIG_NET is not enabled.
Sample of the reported "undefined reference" build errors:
taskstats.c:(.text+0x8f686): undefined reference to `nla_put'
taskstats.c:(.text+0x8f721): undefined reference to `nla_reserve'
taskstats.c:(.text+0x8f8fb): undefined reference to `init_net'
taskstats.c:(.text+0x8f905): undefined reference to `netlink_unicast'
taskstats.c:(.text+0x8f934): undefined reference to `kfree_skb'
taskstats.c:(.text+0x8f9e9): undefined reference to `skb_clone'
taskstats.c:(.text+0x90060): undefined reference to `__alloc_skb'
taskstats.c:(.text+0x901e9): undefined reference to `skb_put'
taskstats.c:(.init.text+0x4665): undefined reference to `genl_register_family'
taskstats.c:(.init.text+0x4699): undefined reference to `genl_register_ops'
taskstats.c:(.init.text+0x4710): undefined reference to `genl_unregister_ops'
taskstats.c:(.init.text+0x471c): undefined reference to `genl_unregister_family'
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
arch/x86/mm/fault.c needs to include asm/vsyscall.h to fix a
build error:
arch/x86/mm/fault.c: In function '__bad_area_nosemaphore':
arch/x86/mm/fault.c:728: error: 'VSYSCALL_START' undeclared (first use in this function)
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-tip:
x86-64: Rework vsyscall emulation and add vsyscall= parameter
x86-64: Wire up getcpu syscall
x86: Remove unnecessary compile flag tweaks for vsyscall code
x86-64: Add vsyscall:emulate_vsyscall trace event
x86-64: Add user_64bit_mode paravirt op
x86-64, xen: Enable the vvar mapping
x86-64: Work around gold bug 13023
x86-64: Move the "user" vsyscall segment out of the data segment.
x86-64: Pad vDSO to a page boundary
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf symbols: Check '/tmp/perf-' symbol file ownership
perf sched: Usage leftover from trace -> script rename
perf sched: Do not delete session object prematurely
perf tools: Check $HOME/.perfconfig ownership
perf, x86: Add model 45 SandyBridge support
perf tools: Add support to install perf python extension
perf tools: do not look at ./config for configuration
perf tools: Make clean leaves some files
perf lock: Dropping unsupported ':r' modifier
perf probe: Fix coredump introduced by probe module option
jump label: Reduce the cycle count by changing the link order
perf report: Use ui__warning in some more places
perf python: Add PERF_RECORD_{LOST,READ,SAMPLE} routine tables
perf evlist: Introduce 'disable' method
trace events: Update version number reference to new 3.x scheme for EVENT_POWER_TRACING_DEPRECATED
perf buildid-cache: Zero out buffer of filenames when adding/removing buildid
There are three choices:
vsyscall=native: Vsyscalls are native code that issues the
corresponding syscalls.
vsyscall=emulate (default): Vsyscalls are emulated by instruction
fault traps, tested in the bad_area path. The actual contents of
the vsyscall page is the same as the vsyscall=native case except
that it's marked NX. This way programs that make assumptions about
what the code in the page does will not be confused when they read
that code.
vsyscall=none: Trying to execute a vsyscall will segfault.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/8449fb3abf89851fd6b2260972666a6f82542284.1312988155.git.luto@mit.edu
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
getcpu is available as a vdso entry and an emulated vsyscall.
Programs that for some reason don't want to use the vdso should
still be able to call getcpu without relying on the slow emulated
vsyscall. It costs almost nothing to expose it as a real syscall.
We also need this for the following patch in vsyscall=native mode.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/6b19f55bdb06a0c32c2fa6dba9b6f222e1fde999.1312988155.git.luto@mit.edu
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
As of commit 98d0ac38ca
Author: Andy Lutomirski <luto@mit.edu>
Date: Thu Jul 14 06:47:22 2011 -0400
x86-64: Move vread_tsc and vread_hpet into the vDSO
user code no longer directly calls into code in arch/x86/kernel/, so
we don't need compile flag hacks to make it safe. All vdso code is
in the vdso directory now.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/835cd05a4c7740544d09723d6ba48f4406f9826c.1312988155.git.luto@mit.edu
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Add support to Romely-EP SandyBridge.
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Anhua Xu <anhua.xu@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1312264895-2010-1-git-send-email-youquan.song@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'stable/bug.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen/trace: Fix compile error when CONFIG_XEN_PRIVILEGED_GUEST is not set
xen: Fix misleading WARN message at xen_release_chunk
xen: Fix printk() format in xen/setup.c
xen/tracing: it looks like we wanted CONFIG_FTRACE
xen/self-balloon: Add dependency on tmem.
xen/balloon: Fix compile errors - missing header files.
xen/grant: Fix compile warning.
xen/pciback: remove duplicated #include
Delete the 10 msec delay between the INIT and SIPI when starting
slave cpus. I can find no requirement for this delay. BIOS also
has similar code sequences without the delay.
Removing the delay reduces boot time by 40 sec. Every bit helps.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/20110805140900.GA6774@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When executing EC commands, only waiting when there are still
more bytes to write is usually fine. However, if the system
suspends very quickly after a call to olpc_ec_cmd(), the last
data byte may not yet be transferred to the EC, and the command
will not complete.
This solves a bug where the SCI wakeup mask was not correctly
written when going into suspend.
It means that sometimes, on XO-1.5 (but not XO-1), the
devices that were marked as wakeup sources can't wake up
the system. e.g. you ask for wifi wakeups, suspend, but then
incoming wifi frames don't wake up the system as they should.
Signed-off-by: Paul Fox <pgf@laptop.org>
Signed-off-by: Daniel Drake <dsd@laptop.org>
Acked-by: Andres Salomon <dilinger@queued.net>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
with CONFIG_XEN and CONFIG_FTRACE set we get this:
arch/x86/xen/trace.c:22: error: ‘__HYPERVISOR_console_io’ undeclared here (not in a function)
arch/x86/xen/trace.c:22: error: array index in initializer not of integer type
arch/x86/xen/trace.c:22: error: (near initialization for ‘xen_hypercall_names’)
arch/x86/xen/trace.c:23: error: ‘__HYPERVISOR_physdev_op_compat’ undeclared here (not in a function)
Issue was that the definitions of __HYPERVISOR were not pulled
if CONFIG_XEN_PRIVILEGED_GUEST was not set.
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Three places in the kernel assume that the only long mode CPL 3
selector is __USER_CS. This is not true on Xen -- Xen's sysretq
changes cs to the magic value 0xe033.
Two of the places are corner cases, but as of "x86-64: Improve
vsyscall emulation CS and RIP handling"
(c9712944b2), vsyscalls will segfault
if called with Xen's extra CS selector. This causes a panic when
older init builds die.
It seems impossible to make Xen use __USER_CS reliably without
taking a performance hit on every system call, so this fixes the
tests instead with a new paravirt op. It's a little ugly because
ptrace.h can't include paravirt.h.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/f4fcb3947340d9e96ce1054a432f183f9da9db83.1312378163.git.luto@mit.edu
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Xen needs to handle VVAR_PAGE, introduced in git commit:
9fd67b4ed0
x86-64: Give vvars their own page
Otherwise we die during bootup with a message like:
(XEN) mm.c:940:d10 Error getting mfn 1888 (pfn 1e3e48) from L1 entry
8000000001888465 for l1e_owner=10, pg_owner=10
(XEN) mm.c:5049:d10 ptwr_emulate: could not get_page_from_l1e()
[ 0.000000] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 0.000000] IP: [<ffffffff8103a930>] xen_set_pte+0x20/0xe0
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/4659478ed2f3480938f96491c2ecbe2b2e113a23.1312378163.git.luto@mit.edu
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Gold has trouble assigning numbers to the location counter inside of
an output section description. The bug was triggered by
9fd67b4ed0, which consolidated all of
the vsyscall sections into a single section. The workaround is IMO
still nicer than the old way of doing it.
This produces an apparently valid kernel image and passes my vdso
tests on both GNU ld version 2.21.51.0.6-2.fc15 20110118 and GNU
gold (version 2.21.51.0.6-2.fc15 20110118) 1.10 as distributed by
Fedora 15.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/0b260cb806f1f9a25c00ce8377a5f035d57f557a.1312378163.git.luto@mit.edu
Reported-by: Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
WARN message should not complain
"Failed to release memory %lx-%lx err=%d\n"
^^^^^^^
about range when it fails to release just one page,
instead it should say what pfn is not freed.
In addition line:
printk(KERN_INFO "xen_release_chunk: looking at area pfn %lx-%lx: "
...
printk(KERN_CONT "%lu pages freed\n", len);
will be broken if WARN in between this line is fired. So fix it
by using a single printk for this.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Use correct format specifier for unsigned long.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Apparently we wanted CONFIG_FTRACE rather the CONFIG_FUNCTION_TRACER.
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Dmitry Kasatkin reports:
"kernel-devel package with kernel headers have no <include/xen>
directory if XEN is disabled. Modules which inclide asm/io.h won't
compile.
XEN related content is behind the CONFIG_XEN flag in the io.h. And
<xen/xen.h> should be also behind CONFIG_XEN flag."
So move the include of <xen/xen.h> down into the section that is
conditional on CONFIG_XEN.
Reported-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6:
cpuidle: stop depending on pm_idle
x86 idle: move mwait_idle_with_hints() to where it is used
cpuidle: replace xen access to x86 pm_idle and default_idle
cpuidle: create bootparam "cpuidle.off=1"
mrst_pmu: driver for Intel Moorestown Power Management Unit
cpuidle users should call cpuidle_call_idle() directly
rather than via (pm_idle)() function pointer.
Architecture may choose to continue using (pm_idle)(),
but cpuidle need not depend on it:
my_arch_cpu_idle()
...
if(cpuidle_call_idle())
pm_idle();
cc: Kevin Hilman <khilman@deeprootsystems.com>
cc: Paul Mundt <lethal@linux-sh.org>
cc: x86@kernel.org
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
...and make it static
no functional change
cc: x86@kernel.org
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
When a Xen Dom0 kernel boots on a hypervisor, it gets access
to the raw-hardware ACPI tables. While it parses the idle tables
for the hypervisor's beneift, it uses HLT for its own idle.
Rather than have xen scribble on pm_idle and access default_idle,
have it simply disable_cpuidle() so acpi_idle will not load and
architecture default HLT will be used.
cc: xen-devel@lists.xensource.com
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
The Moorestown (MRST) Power Management Unit (PMU) driver
directs the SOC power states in the "Langwell" south complex (SCU).
It hooks pci_platform_pm_ops[] and thus observes all PCI ".set_state"
requests. For devices in the SC, the pmu driver translates those
PCI requests into the appropriate commands for the SCU.
The PMU driver helps implement S0i3, a deep system idle power idle state.
Entry into S0i3 is via cpuidle, just like regular processor c-states.
S0i3 depends on pre-conditions including uni-processor, graphics off,
and certain IO devices in the SC must be off. If those pre-conditions
are met, then the PMU allows cpuidle to enter S0i3, otherwise such requests
are demoted, either to Atom C4 or Atom C6.
This driver is based on prototype work by Bruce Flemming,
Illyas Mansoor, Rajeev D. Muralidhar, Vishwesh M. Rudramuni,
Hari Seshadri and Sujith Thomas. The current driver also
includes contributions from H. Peter Anvin, Arjan van de Ven,
Kristen Accardi, and Yong Wang.
Thanks for additional review feedback from Alan Cox and Randy Dunlap.
Acked-by: Alan Cox <alan@linux.intel.com>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
