The driver_override implementation is susceptible to a race condition
when different threads are reading vs storing a different driver
override.  Add locking to avoid this race condition.

Cfr. commits 62655397 ("driver core: platform: fix race
condition with driver_override") and 9561475d ("PCI: Fix race
condition with driver_override").

Fixes: 3cf38571 ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NTodd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

For AMBA devices with unconfigured driver override, the
"driver_override" sysfs virtual file is empty, while it contains
"(null)" for platform and PCI devices.

Make AMBA consistent with other buses by dropping the test for a NULL
pointer.

Note that contrary to popular belief, sprintf() handles NULL pointers
fine; they are printed as "(null)".
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: NTodd Kjos <tkjos@google.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 6b614a87.

My backport was incorrect, as Geert pointed out :(
Reported-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Cc: Todd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When printing the driver_override parameter when it is 4095 and 4094
bytes long, the printing code would access invalid memory because we
need count + 1 bytes for printing.

Cfr. commits 4efe874a ("PCI: Don't read past the end of sysfs
"driver_override" buffer") and bf563b01 ("driver core: platform:
Don't read past the end of "driver_override" buffer").

Fixes: 3cf38571 ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NTodd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The driver_override implementation is susceptible to a race condition
when different threads are reading vs storing a different driver
override.  Add locking to avoid this race condition.

Cfr. commits 62655397 ("driver core: platform: fix race
condition with driver_override") and 9561475d ("PCI: Fix race
condition with driver_override").

Fixes: 3cf38571 ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NTodd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We do not want the common dma_configure() pathway to apply
indiscriminately to all devices, since there are plenty of buses which
do not have DMA capability, and if their child devices were used for
DMA API calls it would only be indicative of a driver bug. However,
there are a number of buses for which DMA is implicitly expected even
when not described by firmware - those we whitelist with an automatic
opt-in to dma_configure(), assuming that the DMA address space and the
physical address space are equivalent if not otherwise specified.

Commit 72328883 ("of: restrict DMA configuration") introduced a
short-term fix by comparing explicit bus types, but this approach is far
from pretty, doesn't scale well, and fails to cope at all with bus
drivers which may be built as modules, like host1x. Let's refine things
by making that opt-in a property of the bus type, which neatly addresses
those problems and lets the decision of whether firmware description of
DMA capability should be optional or mandatory stay internal to the bus
drivers themselves.
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Acked-by: NRob Herring <robh@kernel.org>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The dev_attrs field has long been "depreciated" and is finally being
removed, so move the driver to use the "correct" dev_groups field
instead for struct bus_type.

Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add the call to of_clk_set_defaults() into the amba probe path so
that devices on the amba bus can use the assigned rates and
parents feature of the common clock framework.

Cc: Michael Turquette <mturquette@baylibre.com>
Tested-by: NJorge Ramirez Ortiz <jorge.ramirez-ortiz@linaro.org>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

To read pid/cid registers, the probed device need to be properly turned on.
When it is inside a power domain, the bus code should ensure that the
given power domain is enabled before trying to access device's registers.
However in some cases power domain (or clocks) might not be yet available.
Returning -EPROBE_DEFER is not a solution in such case, because callers
don't handle this special error code. Instead such devices are added to the
special list and their registration is retried from periodic worker until
all resources are available.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

To read pid/cid registers, the probed device need to be properly turned on.
When it is inside a power domain, the bus code should ensure that the
given power domain is enabled before trying to access device's registers.
However in some cases power domain (or clocks) might not be yet available.
Returning -EPROBE_DEFER is not a solution in such case, because callers
don't handle this special error code. Instead such devices are added to the
special list and their registration is retried from periodic worker until
all resources are available.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As already demonstrated with PCI [1] and the platform bus [2], a
driver_override property in sysfs can be used to bypass the id
matching of a device to a AMBA driver. This can be used by VFIO to
bind to any AMBA device requested by the user.

[1] http://lists-archives.com/linux-kernel/28030441-pci-introduce-new-device-binding-path-using-pci_dev-driver_override.html
[2] https://www.redhat.com/archives/libvir-list/2014-April/msg00382.htmlSigned-off-by: NAntonios Motakis <a.motakis@virtualopensystems.com>
Reviewed-by: NKim Phillips <kim.phillips@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The SET_PM_RUNTIME_PM_OPS() and SET_RUNTIME_PM_OPS() macros are
identical except that one of them is not empty for CONFIG_PM set,
while the other one is not empty for CONFIG_PM_RUNTIME set,
respectively.

However, after commit b2b49ccb (PM: Kconfig: Set PM_RUNTIME if
PM_SLEEP is selected) PM_RUNTIME is always set if PM is set, so one
of these macros is now redundant.

For this reason, replace SET_PM_RUNTIME_PM_OPS() with
SET_RUNTIME_PM_OPS() everywhere and redefine the SET_PM_RUNTIME_PM_OPS
symbol as SET_RUNTIME_PM_OPS in case new code is starting to use the
macro being removed here.
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The AMBA bus driver defines runtime Power Management functions which
disable and unprepare AMBA bus clock. This is problematic for runtime PM
because unpreparing a clock might sleep so it is not interrupt safe.

However some drivers may want to implement runtime PM functions in
interrupt-safe way (see pm_runtime_irq_safe()). In such case the AMBA
bus driver should only disable/enable the clock in runtime suspend and
resume callbacks.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

CoreSight components are compliant with the ARM CoreSight
architecture specification and can be connected in various
topologies to suit a particular SoC tracing needs. These trace
components can generally be classified as sources, links and
sinks. Trace data produced by one or more sources flows through
the intermediate links connecting the source to the currently
selected sink.

The CoreSight framework provides an interface for the CoreSight trace
drivers to register themselves with. It's intended to build up a
topological view of the CoreSight components and configure the
correct serie of components on user input via sysfs.

For eg., when enabling a source, the framework builds up a path
consisting of all the components connecting the source to the
currently selected sink(s) and enables all of them.

The framework also supports switching between available sinks
and provides status information to user space applications
through the debugfs interface.
Signed-off-by: NPratik Patel <pratikp@codeaurora.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The commit 46420dd7 (PM / Domains: Add APIs to attach/detach a PM
domain for a device) started using errno values in pm.h header file.
It also failed to include the header for these, thus it caused
compiler errors.

Instead of including the errno header to pm.h, let's move the functions
to pm_domain.h, since it's a better match.

Fixes: 46420dd7 (PM / Domains: Add APIs to attach/detach a PM domain for a device)
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

AMBA devices may on some SoCs resides in PM domains. To be able to
manage these devices from there, let's try to attach devices to their
corresponding PM domain during the probe phase.

To reverse these actions at the remove phase, we try to detach the
device from its PM domain.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Reviewed-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Convert to the SET_PM_RUNTIME_PM macro while defining the runtime PM
callbacks. This means the callbacks becomes available for both
CONFIG_PM_SLEEP and CONFIG_PM_RUNTIME, which is needed by drivers and
power domains.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

To fully gate the clock and thus potentially also save more power in
runtime suspend state, extend clock handling with clk_prepare|unprepare
in the runtime PM callbacks.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

To simplify code and error handling let's use clk_prepare_enable
and clk_disable_unprepare. No functional change.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

All AMBA drivers have converted to use the modern PM ops thus we can
safely drop the legacy PM support from the bus.

While using the modern PM ops it also makes sense to convert to use the
pm_generic callback functions.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

AMBA Primecell devices always treat streaming and coherent DMA exactly
the same, so there's no point in having the masks separated.
Acked-by: NGrant Likely <grant.likely@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The "runtime idle" helper routine, rpm_idle(), currently ignores
return values from .runtime_idle() callbacks executed by it.
However, it turns out that many subsystems use
pm_generic_runtime_idle() which checks the return value of the
driver's callback and executes pm_runtime_suspend() for the device
unless that value is not 0.  If that logic is moved to rpm_idle()
instead, pm_generic_runtime_idle() can be dropped and its users
will not need any .runtime_idle() callbacks any more.

Moreover, the PCI, SCSI, and SATA subsystems' .runtime_idle()
routines, pci_pm_runtime_idle(), scsi_runtime_idle(), and
ata_port_runtime_idle(), respectively, as well as a few drivers'
ones may be simplified if rpm_idle() calls rpm_suspend() after 0 has
been returned by the .runtime_idle() callback executed by it.

To reduce overall code bloat, make the changes described above.
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NKevin Hilman <khilman@linaro.org>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>

CONFIG_HOTPLUG is going away as an option.  As a result, the __dev*
markings need to be removed, as well as the use of CONFIG_HOTPLUG.

This patch does both, removing the use of CONFIG_HOTPLUG in the
amba/bus.c file, and __devinit and __devinitconst in the tegra-ahb.c
driver.

Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This creates amba_apb_device_add_res() and
amba_ahb_device_add_res() respectively, to add devices with
another parent than iomem_resource. This is needed to specify
that a device is contained in a specific IO range.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NAlessandro Rubini <rubini@gnudd.com>
Acked-by: NGiancarlo Asnaghi <giancarlo.asnaghi@st.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This gets rid of the last two users of NO_IRQ in AMBA primecell
drivers.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add two functions to add APB and AHB devices to the amba (PrimeCell)
bus dynamically. This is modeled after the static definition
macros recently introduced into <linux/amba/bus.h> and can
help us in factoring out a bunch of code across the kernel.
Since a lot of call sites seem to be using a returned struct
amba device* pointer, let's use that.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The AMBA bus regulator support is being used to model on/off switches
for power domains which isn't terribly idiomatic for modern kernels with
the generic power domain code and creates integration problems on platforms
which don't use regulators for their power domains as it's hard to tell
the difference between a regulator that is needed but failed to be provided
and one that isn't supposed to be there (though DT does make that easier).

Platforms that wish to use the regulator API to manage their power domains
can indirect via the power domain interface.

This feature is only used with the vape supply of the db8500 PRCMU
driver which supplies the UARTs and MMC controllers, none of which have
support for managing vcore at runtime in mainline (only pl022 SPI
controller does).  Update that supply to have an always_on constraint
until the power domain support for the system is updated so that it is
enabled for these users, this is likely to have no impact on practical
systems as probably at least one of these devices will be active and
cause AMBA to hold the supply on anyway.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Tested-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Make the core warn about the use of -1 (NO_IRQ)
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Fix core bus and MMCI such that irq 0 means that there is no IRQ
attached.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add functions to allocate and initialize AMBA device structures, and
add them to the Linux device manager.  This allows us to kill this
type of operation from individual platforms, moving it to core code.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The forward-only PM callbacks provided by the AMBA bus type are not
necessary any more, because the PM core executes driver callbacks
when the corresponding subsystem callbacks are not present, so drop
them.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

This patch adds the necessary support in file2alias.c to define
suitable aliases based on the amba_id table in AMBA driver modules.

This should be sufficient to allow such modules to be auto-loaded
via udev.  The AMBA bus driver's uevent hotplug code is also
modified to pass an approriate MODALIAS string in the event.

For simplicity, the AMBA ID is treated an an opaque 32-bit numeber.
Module alises use patterns as appropriate to describe the value-
mask pairs described in the driver's amba_id list.

The proposed alias format is (extended regex):

    ^amba:d(HEX){8}$

Where HEX is a single upper-case HEX digit or a pattern (? or []
expression) matching a single upper-case HEX digit, as expected by
udev.

"d" is short for "device", following existing alias naming
conventions for other device types.  This adds some flexibility for
unambiguously extending the alias format in the future by adding
additional leading and trailing fields, if this turns out to be
necessary.
Signed-off-by: NDave Martin <dave.martin@linaro.org>
Acked-by: NPawel Moll <pawel.moll@arm.com>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add runtime PM support to the core Primecell driver, following the PCI
model of how this is done.

Rather than having every driver fiddle about with enabling runtime PM,
that's dealt with in the core and instead, drivers just do a put() in
their probe and a balancing get() in their remove function to activate
runtime PM for the device.

As we're dealing with enabling runtime PM in the core, fix up spi-pl022
as it must not enable and disable runtime PM itself anymore.
Tested-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This makes a hardcoded periphid from the platform override any
magic number found in the hardware. This shall henceforth be used
when the information found in the hardware is either missing,
i.e. not encoding the CID with the magic cookie 0xb105f00d, or
incorrect such that the revision number should have been bumped in
hardware, but the silicon designer has failed to do so.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Xen save/restore is going to use hibernate device callbacks for
quiescing devices and putting them back to normal operations and it
would need to select CONFIG_HIBERNATION for this purpose.  However,
that also would cause the hibernate interfaces for user space to be
enabled, which might confuse user space, because the Xen kernels
don't support hibernation.  Moreover, it would be wasteful, as it
would make the Xen kernels include a substantial amount of code that
they would never use.

To address this issue introduce new power management Kconfig option
CONFIG_HIBERNATE_CALLBACKS, such that it will only select the code
that is necessary for the hibernate device callbacks to work and make
CONFIG_HIBERNATION select it.  Then, Xen save/restore will be able to
select CONFIG_HIBERNATE_CALLBACKS without dragging the entire
hibernate code along with it.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Tested-by: NShriram Rajagopalan <rshriram@cs.ubc.ca>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

Support pm_ops in the AMBA bus, required to allow drivers to use runtime pm.
The implementation of AMBA bus pm ops is based on the platform bus
implementation.
Acked-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

As all probe() functions now take a const pointer, we can make the bus
level code deal with const pointers too.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>