ACPI / osl: speedup grace period in acpi_os_map_cleanup

ACPI maintains cache of ioremap regions to speed up operations and
access to them from irq context where ioremap() calls aren't allowed.
This code abuses synchronize_rcu() on unmap path for synchronization
with fast-path in acpi_os_read/write_memory which uses this cache.

Since v3.10 CPUs are allowed to enter idle state even if they have RCU
callbacks queued, see commit c0f4dfd4f90f1667d234d21f15153ea09a2eaa66
("rcu: Make RCU_FAST_NO_HZ take advantage of numbered callbacks").
That change caused problems with nvidia proprietary driver which calls
acpi_os_map/unmap_generic_address several times during initialization.
Each unmap calls synchronize_rcu and adds significant delay. Totally
initialization is slowed for a couple of seconds and that is enough to
trigger timeout in hardware, gpu decides to "fell off the bus". Widely
spread workaround is reducing "rcu_idle_gp_delay" from 4 to 1 jiffy.

This patch replaces synchronize_rcu() with synchronize_rcu_expedited()
which is much faster.

Link: https://devtalk.nvidia.com/default/topic/567297/linux/linux-3-10-driver-crash/
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Reported-and-tested-by: Alexander Monakov <amonakov@gmail.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: respect the min/max settings from user space

When the user space tries to set scaling_(max|min)_freq through
sysfs, the cpufreq_set_policy() asks other driver's opinions
for the max/min frequencies. Some device drivers, like Tegra
CPU EDP which is not upstreamed yet though, may constrain the
CPU maximum frequency dynamically because of board design.
So if the user space access happens and some driver is capping
the cpu frequency at the same time, the user_policy->(max|min)
is overridden by the capped value, and that's not expected by
the user space. And if the user space is not invoked again,
the CPU will always be capped by the user_policy->(max|min)
even no drivers limit the CPU frequency any more.

This patch preserves the user specified min/max settings, so that
every time the cpufreq policy is updated, the new max/min can
be re-evaluated correctly based on the user's expection and
the present device drivers' status.

Signed-off-by: Vince Hsu <vinceh@nvidia.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
powercap / RAPL: abstract per cpu type functions

RAPL implementations may vary slightly between Core and Atom CPUs. There are
also potential differences among generations of CPUs within the family.

This patch adds a per model structure to abstract the differences such that
variations can be handled cleanly.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
powercap / RAPL: handle atom and core differences

RAPL implementation on Atom has made some changes that are not compatible
with Core CPUs. Specifically, it is different in the way units are computed
as well as floor frequency is enforced.

This patch uses the per CPU model functions to handle the differences. Intel
Software Developers' Manual has also been updated to reflect the changes in
Table 35-7 V3C.

Signed-off-by: Ajay Thomas <ajay.thomas.david.rajamanickam@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
powercap / RAPL: add new model ids

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / LPSS: add all LPSS devices to the specific power domain

Currently the LPSS devices are located in the different power domains depends
on LPSS_SAVE_CTX flag. We would like to use the specific power domain for all
LPSS devices.

The LPSS DMA controller has no knobs to control its power state. The specific
power domain implementation will handle this case. The patch does a preparation
for that.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Scott Ashcroft <scott.ashcroft@talk21.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / LPSS: allow to use specific PM domain during ->probe()

The LPSS DMA controller would like to use the specific PM domain callbacks
during early stage, namely in ->probe(). This patch moves the specific PM
domain assignment early to be accessible during a whole life time of the device
in the system.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Scott Ashcroft <scott.ashcroft@talk21.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / LPSS: introduce a 'proxy' device to power on LPSS for DMA

The LPSS DMA controller does not have _PS0 and _PS3 methods. Moreover it can be
powered off automatically whenever the last LPSS device goes down. In case of
no power any access to the DMA controller will hang the system. The behaviour
is reproduced on some HP laptops based on Intel Bay Trail [1] as well as on
Asus T100 transformer.

This patch introduces a so called 'proxy' device that has the knobs to handle a
power of the LPSS island. When the system needs to program the DMA controller
it calls to the ACPI LPSS power domain callbacks that wake or suspend the
'proxy' device.

[1] http://www.spinics.net/lists/dmaengine/msg01514.html

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Scott Ashcroft <scott.ashcroft@talk21.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
dmaengine: dw: enable runtime PM

On runtime PM aware platforms the DMA have to manage its own power state. This
patch enables runtime PM support and applies necessary calls wherever it's
needed.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Tested-by: Scott Ashcroft <scott.ashcroft@talk21.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / OSL: Add IRQ handler flushing support in the OSL.

It is possible that a GPE handler or a fixed event handler still accessed
after removing the handlers by invoking acpi_remove_gpe_handler() or
acpi_remove_fixed_event_handler(), this possibility can crash OPSM after a
module removal. In the Linux kernel, though all other GPE drivers are not
modules, since the IPMI_SI (ipmi_si_intf.c) can be compiled as a module, we
still need to consider a solution for this issue when the driver switches
to ACPI_GPE_RAW_HANDLER mode in order to invoke GPE APIs.

ACPICA expects acpi_os_wait_events_complete() to be invoked after GPE
disabling so that OSPM can ensure all running GPE handlers have exitted.
But currently acpi_os_wait_events_complete() can only flush _Lxx/_Exx
evaluation work queue and this philosophy cannot work for drivers that have
installed a dedicated GPE handler.

The only way to protect a callback is to perform some state holders
(reference count, state machine) before invoking the callback. Then this
issue can only be fixed by the following means:
1. Flush GPE in ACPICA before invoking the GPE handler. But currently,
   there is no such implementation in acpi_ev_gpe_dispatch().
2. Flush GPE in ACPICA OSL before invoking the SCI handler. But currently,
   there is no such implementation in acpi_irq().
3. Flush IRQ in OSPM IRQ layer before invoking the IRQ handler. In Linus
   kernel, this can be done by synchronize_irq().
4. Flush scheduling in OSPM vector entry layer before invoking the vector.
   In Linux, this can be done by synchronize_sched().

Since ACPICA expects the GPE handlers to be flushed by the ACPICA OSL or
the GPE drivers. If it is implemented by the GPE driver, we should see
synchronize_irq()/synchronize_sched() invoked in such drivers. If it is
implemented by the ACPICA OSL, ACPICA currently provides
acpi_os_wait_events_complete() hook to achieve this. After the following
commit:
  Commit: 69c841b6dd8313c9a673246cc0e2535174272cab
  Author: Lv Zheng <lv.zheng@intel.com>
  Subject: ACPICA: Update use of acpi_os_wait_events_complete interface.
The OSL acpi_os_wait_events_complete() is invoked after a GPE handler is
removed from acpi_remove_gpe_handler() or a fixed event handler is removed
from acpi_remove_fixed_event_handler(). Thus it is possible to implement
GPE handler flushing using this ACPICA OSL now. So the solution 1 is
currently not taken into account.

By examining the IPMI_SI driver, we noticed that the IPMI_SI driver:
1. Uses free_irq() to flush non GPE based IRQ handlers, in free_irq(),
   synchronize_irq() is invoked, and
2. Uses acpi_remove_gpe_handler() to flush GPE based IRQ handlers, for such
   IRQ handlers, there is no synchronize_irq() invoked.
Since there isn't synchronize_sched() implemented for this driver, from the
driver's perspective, acpi_remove_gpe_handler() should have properly
flushed the GPE handlers for it. Since the driver doesn't invoke
synchronize_irq(), the solution 3 is not what the drivers expect.

This patch implements solution 2. But since given the fact that the GPE is
managed inside of ACPICA, and implementing the GPE flushing requires to
implement the whole GPE management code again in the OSL, instead of
flushing GPE, this patch flushes IRQ in acpi_os_wait_events_complete(). The
flushing could last longer than expected as though the target GPE/fixed
event that is removed can be fastly flushed, other GPEs/fix events can still
be issued during the flushing period.

This patch fixes this issue by invoking synchronize_hardirq() in
acpi_os_wait_events_complete(). The reason why we don't invoke
synchronize_irq() is: currently ACPICA is not threaded IRQ capable and the
only difference between synchronize_irq() and synchronize_hardirq() is
synchronize_irq() also flushes threaded IRQ handlers. Thus using
synchronize_hardirq() can help to reduce the overall synchronization time
for the current ACPICA implementation.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Corey Minyard <minyard@acm.org>
Cc: linux-acpi@vger.kernel.org
Cc: devel@acpica.org
Cc: openipmi-developer@lists.sourceforge.net
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
x86: Add support for Intel HWP feature detection.

Add support of Hardware Managed Performance States (HWP) described in Volume 3
section 14.4 of the SDM.

One bit CPUID.06H:EAX[bit 7] expresses the presence of the HWP feature on
the processor. The remaining bits CPUID.06H:EAX[bit 8-11] denote the
presense of various HWP features.

Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
intel_pstate: Add support for HWP

Add support of Hardware Managed Performance States (HWP) described in Volume 3
section 14.4 of the SDM.

With HWP enbaled intel_pstate will no longer be responsible for selecting P
states for the processor. intel_pstate will continue to register to
the cpufreq core as the scaling driver for CPUs implementing
HWP. In HWP mode intel_pstate provides three functions reporting
frequency to the cpufreq core, support for the set_policy() interface
from the core and maintaining the intel_pstate sysfs interface in
/sys/devices/system/cpu/intel_pstate.  User preferences expressed via
the set_policy() interface or the sysfs interface are forwared to the
CPU via the HWP MSR interface.

Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
intel_pstate: Add CPUID for BDW-H CPU

Add BDW-H to the list of supported processors.

Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / EC: Introduce STARTED/STOPPED flags to replace BLOCKED flag.

By using the 2 flags, we can indicate an inter-mediate state where the
current transactions should be completed while the new transactions should
be dropped.

The comparison of the old flag and the new flags:
  Old			New
  about to set BLOCKED	STOPPED set / STARTED set
  BLOCKED set		STOPPED clear / STARTED clear
  BLOCKED clear		STOPPED clear / STARTED set
The new period is between the point where we are about to set BLOCKED and
the point when the BLOCKED is set. The GPE is disabled during this period.
The new flags allow us to add acpi_ec_stopped() check to only check with
STOPPED flag to implement transaction flushing. This is not done in this
patch.

No functional changes except that after applying this patch, the GPE
enabling/disabling is protected by the EC specific lock. We can do this
because of recent ACPICA GPE API enhancement. This is reasonable as the GPE
disabling/enabling state should only be determined by the EC driver's state
machine which is protected by the EC spinlock.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Tested-by: Ortwin Glück <odi@odi.ch>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / EC: Enhance the checks to apply to QR_EC transactions.

Currently a check is applied to new transactions, but QR_EC transactions
are not included. This patch merges the code path to make the check also
applying to the QR_EC transactions.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Tested-by: Ortwin Glück <odi@odi.ch>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / EC: Add reference counting for query handlers.

This patch adds reference counting for query handlers in order to eliminate
kmalloc()/kfree() usage.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Tested-by: Steffen Weber <steffen.weber@gmail.com>
Tested-by: Ortwin Glück <odi@odi.ch>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / EC: Add command flushing support.

This patch implements command flushing support. It's better to wait all
command transactions to be completed before disabling the EC GPE when the
system is going to be suspended. By doing so, the EC hardware can be
ensured to be in the idle state when the system is resumed.

There is a good indicator for flush support:
All acpi_ec_submit_request() is invoked after checking driver state with
acpi_ec_started() except the first one. This means all code paths can be
flushed as fast as possible by discarding the requests occurred after the
flush operation. The reference increased for such kind of code path is
wrapped by acpi_ec_submit_flushable_request().

The system suspending/resuming test result is as follows:
  ACPI : EC: +++++ Stopping EC +++++
* ACPI : EC: +++++ EC stopped +++++
  ACPI : EC: +++++ Starting EC +++++
# ACPI : EC: +++++ EC started +++++
This is performed by "switching wireless switch on/off" and "plugging power
cord in/out" frequently during the suspending/resuming. The above dmesg
shows that the EC driver is stopped during suspending (*) and is restarted
during resuming (#) correctly.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Tested-by: Ortwin Glück <odi@odi.ch>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
powercap / RAPL: fix build dependency on iosf_mbi

RAPL on Atom depends on IOSF_MBI driver for setting
floor frequency. This patch adds explicit dependency on
CONFIG_IOSF_MB.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpuidle: Invert CPUIDLE_FLAG_TIME_VALID logic

The only place where the time is invalid is when the ACPI_CSTATE_FFH entry
method is not set. Otherwise for all the drivers, the time can be correctly
measured.

Instead of duplicating the CPUIDLE_FLAG_TIME_VALID flag in all the drivers
for all the states, just invert the logic by replacing it by the flag
CPUIDLE_FLAG_TIME_INVALID, hence we can set this flag only for the acpi idle
driver, remove the former flag from all the drivers and invert the logic with
this flag in the different governor.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM / Domains: Make genpd parameter of pm_genpd_present() const

The PM domain pointed to by the genpd parameter is never modified.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>