Add PCI-specific dev_printk() wrappers and use them to simplify the code
slightly.  No functional change intended.
Signed-off-by: NFrederick Lawler <fred@fredlawl.com>
[bhelgaas: squash into one patch]
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Add and use #defines for L1 Substate register fields instead of hard-coding
the masks.  Also update comments to use names from the spec.  No functional
change intended.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NVidya Sagar <vidyas@nvidia.com>

Previously we programmed the LTR_L1.2_THRESHOLD in the parent (upstream)
device using the capability pointer of the *child* (downstream) device,
which corrupted some random word of the parent's config space.

Use the parent's L1 SS capability pointer to program its
LTR_L1.2_THRESHOLD.

Fixes: aeda9ade ("PCI/ASPM: Configure L1 substate settings")
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NVidya Sagar <vidyas@nvidia.com>
CC: stable@vger.kernel.org	# v4.11+
CC: Rajat Jain <rajatja@google.com>

Every Port that supports the L1.2 substate advertises its Port
Common_Mode_Restore_Time, i.e., the time the Port requires to re-establish
common mode when exiting L1.2 (see PCIe r3.1, sec 7.33.2).

Per sec 5.5.3.3.1, when exiting L1.2, the Downstream Port (the device at
the upstream end of the link) must send TS1 training sequences for at least
T(COMMONMODE) after it detects electrical idle exit on the Link.  We want
this to be long enough for both ends of the Link, so we should set it to
the maximum of the Port Common_Mode_Restore_Time for the upstream and
downstream components on the Link.

Previously we only looked at the Port Common_Mode_Restore_Time of the
upstream device, so if the downstream device required more time, we didn't
program the upstream device's T(COMMONMODE) correctly.

Fixes: f1f0366d ("PCI/ASPM: Calculate and save the L1.2 timing parameters")
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NVidya Sagar <vidyas@nvidia.com>
Acked-by: NRajat Jain <rajatja@google.com>
CC: stable@vger.kernel.org	# v4.11+

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Several function prototypes for the set/get functions defined by
module_param_call() have a slightly wrong argument types. This fixes
those in an effort to clean up the calls when running under type-enforced
compiler instrumentation for CFI. This is the result of running the
following semantic patch:

@match_module_param_call_function@
declarer name module_param_call;
identifier _name, _set_func, _get_func;
expression _arg, _mode;
@@

 module_param_call(_name, _set_func, _get_func, _arg, _mode);

@fix_set_prototype
 depends on match_module_param_call_function@
identifier match_module_param_call_function._set_func;
identifier _val, _param;
type _val_type, _param_type;
@@

 int _set_func(
-_val_type _val
+const char * _val
 ,
-_param_type _param
+const struct kernel_param * _param
 ) { ... }

@fix_get_prototype
 depends on match_module_param_call_function@
identifier match_module_param_call_function._get_func;
identifier _val, _param;
type _val_type, _param_type;
@@

 int _get_func(
-_val_type _val
+char * _val
 ,
-_param_type _param
+const struct kernel_param * _param
 ) { ... }

Two additional by-hand changes are included for places where the above
Coccinelle script didn't notice them:

	drivers/platform/x86/thinkpad_acpi.c
	fs/lockd/svc.c
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NJessica Yu <jeyu@kernel.org>

Even though it is unconventional, some PCIe host implementations omit the
root ports entirely, and simply consist of a host bridge (which is not
modeled as a device in the PCI hierarchy) and a link.

When the downstream device is an endpoint, our current code does not seem
to mind this unusual configuration. However, when PCIe switches are
involved, the ASPM code assumes that any downstream switch port has a
parent, and blindly dereferences the bus->parent->self field of the pci_dev
struct to chain the downstream link state to the link state of the root
port. Given that the root port is missing, the link is not modeled at all,
and nor is the link state, and attempting to access it results in a NULL
pointer dereference and a crash.

Avoid this by allowing the link state chain to terminate at the downstream
port if no root port exists.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

We call pcie_aspm_exit_link_state() when we remove a device.  If the device
is the last PCIe function to be removed below a bridge and the bridge has
an ASPM link_state struct, we disable ASPM on the link.  Disabling ASPM
requires link->downstream (used in pcie_config_aspm_link()).

We previously set link->downstream in pcie_aspm_cap_init(), but only if the
device was not blacklisted.  Removing the blacklisted device caused a NULL
pointer dereference in the pcie_aspm_exit_link_state() ->
pcie_config_aspm_link() path:

  # echo 1 > /sys/bus/pci/devices/0000\:0b\:00.0/remove
  ...
   BUG: unable to handle kernel NULL pointer dereference at 0000000000000080
   IP: pcie_config_aspm_link+0x5d/0x2b0
   Call Trace:
    pcie_aspm_exit_link_state+0x75/0x130
    pci_stop_bus_device+0xa4/0xb0
    pci_stop_and_remove_bus_device_locked+0x1a/0x30
    remove_store+0x50/0x70
    dev_attr_store+0x18/0x30
    sysfs_kf_write+0x44/0x60
    kernfs_fop_write+0x10e/0x190
    __vfs_write+0x28/0x110
    ? rcu_read_lock_sched_held+0x5d/0x80
    ? rcu_sync_lockdep_assert+0x2c/0x60
    ? __sb_start_write+0x173/0x1a0
    ? vfs_write+0xb3/0x180
    vfs_write+0xc4/0x180
    SyS_write+0x49/0xa0
    do_syscall_64+0xa6/0x1c0
    entry_SYSCALL64_slow_path+0x25/0x25
   ---[ end trace bd187ee0267df5d9 ]---

To avoid this, set link->downstream in alloc_pcie_link_state(), so every
pcie_link_state structure has a valid link->downstream pointer.

[bhelgaas: changelog]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRajat Jain <rajatja@google.com>
CC: stable@vger.kernel.org

Since the exit latencies for L1 substates are not advertised by a device,
it is not clear in spec how to do a L1 substate exit latency check.  We
assume that the L1 exit latencies advertised by a device include L1
substate latencies (and hence do not do any check).  If that is not true,
we should do some sort of check here.

(I'm not clear about what that check should like currently. I'd be glad to
take up any suggestions).
Signed-off-by: NRajat Jain <rajatja@google.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Configure the L1 substate settings on the upstream and downstream devices,
while taking care of the rules dictated by the PCIe spec.

[bhelgaas: drop "inline"]
Signed-off-by: NRajat Jain <rajatja@google.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Calculate and save the timing parameters that need to be programmed if we
need to enable L1.2 substates later.

We use the same logic (and a constant value for 1 of the parameters) as
used by Intel's coreboot:

  https://www.coreboot.org/pipermail/coreboot-gerrit/2015-March/021134.html
  https://review.coreboot.org/#/c/8832/Signed-off-by: NRajat Jain <rajatja@google.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

The PCIe spec (r3.1, sec 7.33) says the L1 PM Substates Capability may be
implemented only in function 0.

Read the L1 substate capability structures of upstream and downstream
components of the link and set it up in the device structure.

[bhelgaas: add specific spec reference]
Signed-off-by: NRajat Jain <rajatja@google.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Add support for ASPM L1 substates.  For details about L1 substates, see the
PCIe r3.1 spec, which includes the ECN below in secs 5.5 and 7.33.

Add macros for the 4 new L1 substates, and add a new ASPM "POWER_SUPERSAVE"
policy that can be used to enable L1 substates on a system if desired.  The
new policy is in a sense, a superset of the existing POWERSAVE policy.  The
4 policies are now:

  DEFAULT: Reads and uses whatever ASPM states BIOS enabled
  PERFORMANCE: Everything except L0 disabled.
  POWERSAVE: L0s and L1 enabled (but not L1 substates)
  POWER_SUPERSAVE: L0s + L1 + L1 substates also enabled

[bhelgaas: add PCIe r3.1 spec reference]
Link: https://pcisig.com/sites/default/files/specification_documents/ECN_L1_PM_Substates_with_CLKREQ_31_May_2013_Rev10a.pdfSigned-off-by: NRajat Jain <rajatja@google.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

In a struct pcie_link_state, link->root points to the pcie_link_state of
the root of the PCIe hierarchy.  For the topmost link, this points to
itself (link->root = link).  For others, we copy the pointer from the
parent (link->root = link->parent->root).

Previously we recognized that Root Ports originated PCIe hierarchies, but
we treated PCI/PCI-X to PCIe Bridges as being in the middle of the
hierarchy, and when we tried to copy the pointer from link->parent->root,
there was no parent, and we dereferenced a NULL pointer:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000090
  IP: [<ffffffff9e424350>] pcie_aspm_init_link_state+0x170/0x820

Recognize that PCI/PCI-X to PCIe Bridges originate PCIe hierarchies just
like Root Ports do, so link->root for these devices should also point to
itself.

Fixes: 51ebfc92 ("PCI: Enumerate switches below PCI-to-PCIe bridges")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=193411
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1022181
Tested-by: lists@ssl-mail.com
Tested-by: NJayachandran C. <jnair@caviumnetworks.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org	# v4.2+

Some (defective) PCIe devices are not able to reliably do link retraining.

Check to see if ASPM is possible between link partners before configuring
common clocking, and doing the resulting link retraining.  If ASPM is not
possible, there is no reason to risk losing access to a device due to an
unnecessary link retraining.
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Use DEVICE_ATTR_RW for read-write attributes.  This simplifies the source
code, improves readability, and reduces the chance of inconsistencies.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@rw@
declarer name DEVICE_ATTR;
identifier x,x_show,x_store;
@@

DEVICE_ATTR(x, \(0644\|S_IRUGO|S_IWUSR\), x_show, x_store);

@script:ocaml@
x << rw.x;
x_show << rw.x_show;
x_store << rw.x_store;
@@

if not (x^"_show" = x_show && x^"_store" = x_store)
then Coccilib.include_match false

@@
declarer name DEVICE_ATTR_RW;
identifier rw.x,rw.x_show,rw.x_store;
@@

- DEVICE_ATTR(x, \(0644\|S_IRUGO|S_IWUSR\), x_show, x_store);
+ DEVICE_ATTR_RW(x);
// </smpl>
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Without supporting clock PM capable, if we want to disable clkpm, we don't
need this extra check as it must already be zero for the enable argument.
And it's the same for enabling clkpm here.  So let's remove this check.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

If CONFIG_PCIEASPM_DEBUG is set, then PCI devices have a link_state
attribute.  Reading that attribute shows the state as a bit mask: 1
means L0S upstream, 2 means L0S downstream, and 4 means L1.

Oddly, writing to link_state is inconsistent and gets translated, leading
to mysterious results in which the value you store isn't comparable the
value you load back out.

Fix it by making link_state_store() match link_state_show().

[bhelgaas: Check "aspm_disabled" *before* validating input.  When
"aspm_disabled" is set, this changes the error for invalid input from
-EINVAL to -EPERM.]
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Update the Link Control Enable Clock Power Management bit the same
way we update the ASPM Control bits, with a single call of
pcie_capability_clear_and_set_word().

No functional change; this just makes both paths use the same style.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

We allocate pcie_link_state for the component at the upstream end of a
Link.  Previously we did this by allocating pcie_link_state for Root Ports
and Downstream Ports.  This works fine for the typical topology:

  00:1c.0 Root Port       [bridge to bus 02]
  02:00.0 Upstream Port   [bridge to bus 03]
  03:00.0 Downstream Port [bridge to bus 04]
  04:00.0 Endpoint or Switch Port

However, it is possible to have a Root Port connected to a Downstream Port
instead of an Upstream Port, as in Robert White's ATCA system:

  00:1c.0 Root Port       [bridge to bus 02]
  02:00.0 Downstream Port [bridge to bus 03]
  03:01.0 Downstream Port [bridge to bus 04]
  04:00.0 Endpoint or Switch Port

In this topology, we wrongly allocated pcie_link_state for the 02:00.0
Downstream Port, which is actually the *downstream* end of a link.  This
led to the following NULL pointer dereference when we tried to connect this
link into the tree of links starting at the 00:1c.0 Root Port:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000088
  IP: [<ffffffff81550324>] pcie_aspm_init_link_state+0x744/0x850
  Hardware name: Kontron B3001/B3001, BIOS 4.6.3 08/07/2012
  Call Trace:
   [<ffffffff8153b865>] pci_scan_slot+0xd5/0x120
   [<ffffffff8153ca1d>] pci_scan_child_bus+0x2d/0xd0
   ...

Instead of relying on the component type to identify the upstream end of a
link, use the "dev->has_secondary_link" field.

This means it's now possible for an Upstream Port to have a link on its
secondary side, so alloc_pcie_link_state() needs to connect links
originating from both Upstream and Downstream Ports into the tree.

[bhelgaas: changelog, add comment]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=94361
Link: http://lkml.kernel.org/r/54EB81B2.4050904@pobox.comReported-by: NRobert White <rwhite@pobox.com>
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

We decide in alloc_pcie_link_state() whether to allocate a pcie_link_state
for a device.  After that, it's sufficient to check pdev->link_state.  We
don't need to check the PCIe port type again.

Remove the redundant PCIe port type checking.

[bhelgaas: changelog]
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

After 387d3757 ("PCI: Don't clear ASPM bits when the FADT declares it's
unsupported"), the "force" parameter to __pci_disable_link_state() is
always "false".

Remove the "force" parameter and assume it's always false.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Communications with a hardware vendor confirm that the expected behaviour
on systems that set the FADT ASPM disable bit but which still grant full
PCIe control is for the OS to leave any BIOS configuration intact and
refuse to touch the ASPM bits.  This mimics the behaviour of Windows.
Signed-off-by: NMatthew Garrett <mjg59@coreos.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

The functions link_state_store() and clk_ctl_store() had just subtracted
ASCII '0' from input which could lead to undesired results.  Instead, use
Linux string functions to safely parse input.

[bhelgaas: check kstrtouint() return value]
Signed-off-by: NChris J Arges <chris.j.arges@canonical.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

My philosophy is unused code is dead code.  And dead code is subject to bit
rot and is a likely source of bugs.  Use it or lose it.

This reverts part of 3e1b1600 ("ACPI/PCI: PCIe ASPM _OSC support
capabilities called when root bridge added"), removing this interface:

    pcie_aspm_enabled()

[bhelgaas: split to separate patch]
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: Andrew Patterson <andrew.patterson@hp.com>

Fix whitespace, capitalization, and spelling errors.  No functional change.
I know "busses" is not an error, but "buses" was more common, so I used it
consistently.

Signed-off-by: Marta Rybczynska <rybczynska@gmail.com> (pci_reset_bridge_secondary_bus())
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Fix kerneldoc for pci_disable_link_state().

[bhelgaas: expand comment, fix typos]
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Some devices have hardware problems related to using ASPM.  Drivers for
these devices use pci_disable_link_state() to prevent their device from
entering L0s or L1.  But on platforms where the OS doesn't have permission
to manage ASPM, pci_disable_link_state() doesn't actually disable ASPM.

Windows has a similar mechanism ("PciASPMOptOut"), and when the OS doesn't
have control of ASPM, it doesn't actually disable ASPM either.

This patch just adds a warning in dmesg about the fact that
pci_disable_link_state() is doing nothing.
Reported-by: NEmmanuel Grumbach <egrumbach@gmail.com>
Reference: https://lkml.kernel.org/r/CANUX_P3F5YhbZX3WGU-j1AGpbXb_T9Bis2ErhvKkFMtDvzatVQ@mail.gmail.com
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=57331Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Don't allocate and track PCIe ASPM state when "pcie_aspm=off" is specified
on the kernel command line.

Based-on-patch-from: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: NJoe Lawrence <joe.lawrence@stratus.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NDavid Bulkow <david.bulkow@stratus.com>
Acked-by: NMyron Stowe <myron.stowe@redhat.com>

On PCI bus hotplug removal, pcie_aspm_exit_link_state() can potentially
skip parent devices that have link_state allocated.  Instead of exiting
early if a given device is not PCIe, check whether or not the device's
parent has link_state allocated.  This enables pcie_aspm_exit_link_state()
to properly clean up parent link_state when the last function in a slot
might not be PCIe.
Reported-by: NJoe Lawrence <joe.lawrence@stratus.com>
Tested-by: NJoe Lawrence <joe.lawrence@stratus.com>
Signed-off-by: NMyron Stowe <myron.stowe@redhat.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Right now using pcie_aspm=force will not enable ASPM if the FADT indicates
ASPM is unsupported.  However, the semantics of force should probably allow
for this, especially as they did before 3c076351 ("PCI: Rework ASPM
disable code")

This patch just skips the clearing of any ASPM setup that the firmware has
carried out on this bus if pcie_aspm=force is being used.

Reference: http://bugs.launchpad.net/bugs/962038Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org

Add standard #defines for ASPM fields in PCI Express Link Capability and
Link Control registers.

Previously we used PCIE_LINK_STATE_L0S and PCIE_LINK_STATE_L1 directly, but
these are defined for the Linux ASPM interfaces, e.g.,
pci_disable_link_state(), and only coincidentally match the actual register
bits.  PCIE_LINK_STATE_CLKPM, also part of that interface, does not match
the register bit.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Acked-by: NKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>

dev_<level> calls take less code than dev_printk(KERN_<LEVEL>
and reducing object size is good.
Coalesce formats for easier grep.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Use PCI Express Capability access functions to simplify PCIe ASPM.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Introduce an inline function pci_pcie_type(dev) to extract PCIe
device type from pci_dev->pcie_flags_reg field, and prepare for
removing pci_dev->pcie_type.
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Since 3.2.12 and 3.3, some systems are failing to boot with a BUG_ON.
Some other systems using the pata_jmicron driver fail to boot because no
disks are detected.  Passing pcie_aspm=force on the kernel command line
works around it.

The cause: commit 4949be16 ("PCI: ignore pre-1.1 ASPM quirking when
ASPM is disabled") changed the behaviour of pcie_aspm_sanity_check() to
always return 0 if aspm is disabled, in order to avoid cases where we
changed ASPM state on pre-PCIe 1.1 devices.

This skipped the secondary function of pcie_aspm_sanity_check which was
to avoid us enabling ASPM on devices that had non-PCIe children, causing
trouble later on.  Move the aspm_disabled check so we continue to honour
that scenario.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=42979 and
          http://bugs.debian.org/665420

Reported-by: Romain Francoise <romain@orebokech.com> # kernel panic
Reported-by: Chris Holland <bandidoirlandes@gmail.com> # disk detection trouble
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Cc: stable@vger.kernel.org
Tested-by: Hatem Masmoudi <hatem.masmoudi@gmail.com> # Dell Latitude E5520
Tested-by: janek <jan0x6c@gmail.com> # pata_jmicron with JMB362/JMB363
[jn: with more symptoms in log message]
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Right now we won't touch ASPM state if ASPM is disabled, except in the case
where we find a device that appears to be too old to reliably support ASPM.
Right now we'll clear it in that case, which is almost certainly the wrong
thing to do. The easiest way around this is just to disable the blacklisting
when ASPM is disabled.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

Distributions may wish to provide different defaults for PCIE ASPM
depending on their target audience. Provide a configuration option for
choosing the default policy.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

Right now we forcibly clear ASPM state on all devices if the BIOS indicates
that the feature isn't supported. Based on the Microsoft presentation
"PCI Express In Depth for Windows Vista and Beyond", I'm starting to think
that this may be an error. The implication is that unless the platform
grants full control via _OSC, Windows will not touch any PCIe features -
including ASPM. In that case clearing ASPM state would be an error unless
the platform has granted us that control.

This patch reworks the ASPM disabling code such that the actual clearing
of state is triggered by a successful handoff of PCIe control to the OS.
The general ASPM code undergoes some changes in order to ensure that the
ability to clear the bits isn't overridden by ASPM having already been
disabled. Further, this theoretically now allows for situations where
only a subset of PCIe roots hand over control, leaving the others in the
BIOS state.

It's difficult to know for sure that this is the right thing to do -
there's zero public documentation on the interaction between all of these
components. But enough vendors enable ASPM on platforms and then set this
bit that it seems likely that they're expecting the OS to leave them alone.

Measured to save around 5W on an idle Thinkpad X220.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

Right now we forcibly clear ASPM state on all devices if the BIOS indicates
that the feature isn't supported. Based on the Microsoft presentation
"PCI Express In Depth for Windows Vista and Beyond", I'm starting to think
that this may be an error. The implication is that unless the platform
grants full control via _OSC, Windows will not touch any PCIe features -
including ASPM. In that case clearing ASPM state would be an error unless
the platform has granted us that control.

This patch reworks the ASPM disabling code such that the actual clearing
of state is triggered by a successful handoff of PCIe control to the OS.
The general ASPM code undergoes some changes in order to ensure that the
ability to clear the bits isn't overridden by ASPM having already been
disabled. Further, this theoretically now allows for situations where
only a subset of PCIe roots hand over control, leaving the others in the
BIOS state.

It's difficult to know for sure that this is the right thing to do -
there's zero public documentation on the interaction between all of these
components. But enough vendors enable ASPM on platforms and then set this
bit that it seems likely that they're expecting the OS to leave them alone.

Measured to save around 5W on an idle Thinkpad X220.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>