Export the dw_pcie_wait_for_link() function to be able to build drivers
using it as loadable modules.
Signed-off-by: NVidya Sagar <vidyas@nvidia.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Add extended configuration space capability search API using struct
dw_pcie* pointer.
Signed-off-by: NVidya Sagar <vidyas@nvidia.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: NGustavo Pimentel <gustavo.pimentel@synopsys.com>
Acked-by: NThierry Reding <treding@nvidia.com>

Move PCIe config space capability search API to common DesignWare file
as this can be used by both host and EP mode drivers.
Signed-off-by: NVidya Sagar <vidyaos@nvidia.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NThierry Reding <treding@nvidia.com>
Acked-by: NGustavo Pimentel <gustavo.pimentel@synopsys.com>

Some of DesignWare core's DBI registers (a.k.a configuration space
registers) are write-protected with a lock without enabling which they
are read-only by default.

These write-protected registers are implementation specific. Tegra194's
BAR-0 register which is at offset 0x10 in the configuration space is an
example. Current implementation in dw_pcie_setup_rc() API attempts to
unlock those write-protected registers whenever they are updated and
lock them back again for writing.

Group all write-protected registers writes so that locking and unlocking
is performed once to avoid bloating the code with multiple unlock/lock
sequences for all those write-protected registers.
Signed-off-by: NVidya Sagar <vidyas@nvidia.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NThierry Reding <treding@nvidia.com>
Acked-by: NJingoo Han <jingoohan1@gmail.com>

If CONFIG_GPIOLIB is not selected the compilation results in the
following build errors:

drivers/pci/controller/dwc/pci-dra7xx.c:
 In function dra7xx_pcie_probe:
drivers/pci/controller/dwc/pci-dra7xx.c:777:10:
 error: implicit declaration of function devm_gpiod_get_optional;
 did you mean devm_regulator_get_optional? [-Werror=implicit-function-declaration]

  reset = devm_gpiod_get_optional(dev, NULL, GPIOD_OUT_HIGH);

drivers/pci/controller/dwc/pci-dra7xx.c:778:45: error: ‘GPIOD_OUT_HIGH’
undeclared (first use in this function); did you mean ‘GPIOF_INIT_HIGH’?
  reset = devm_gpiod_get_optional(dev, NULL, GPIOD_OUT_HIGH);
                                             ^~~~~~~~~~~~~~
                                             GPIOF_INIT_HIGH

Fix them by including the appropriate header file.
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
[lorenzo.pieralisi@arm.com: commit log]
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: NKishon Vijay Abraham I <kishon@ti.com>

Fix typos in drivers/pci.  Comment and whitespace changes only.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: NRandy Dunlap <rdunlap@infradead.org>

The imx6 driver can be used on imx6sx without enabling support for
imx6q or imx7d but the "depends on" condition doesn't allow that.

Instead of making the condition even longer just make it depend on
"ARCH_MXC || COMPILE_TEST" instead.
Signed-off-by: NLeonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: NLucas Stach <l.stach@pengutronix.de>

Export all configuration space access APIs and also other APIs to
support host controller drivers of dwc core based implementations while
adding support for .remove() hook to build their respective drivers as
modules.
Signed-off-by: NVidya Sagar <vidyas@nvidia.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: NGustavo Pimentel <gustavo.pimentel@synopsys.com>

Cleanup DBI read and write APIs by removing leading "__" (underscore)
from their names as there is no reason to have leading underscores
in the first place in the function definition.

Remove dbi/dbi2 base address parameters as the same behaviour can be
obtained through read and write APIs. Since dw_pcie_{readl/writel}_dbi()
APIs can't be used for ATU read/write as ATU base address could be
different from DBI base address, implement ATU read/write APIs using ATU
base address without using dw_pcie_{readl/writel}_dbi() APIs.
Signed-off-by: NVidya Sagar <vidyas@nvidia.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: NJingoo Han <jingoohan1@gmail.com>

Add an API to group all the tasks to be done to de-initialize host which
can then be called by any dwc core based driver implementations
while adding .remove() support in their respective drivers.
Signed-off-by: NVidya Sagar <vidyas@nvidia.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: NGustavo Pimentel <gustavo.pimentel@synopsys.com>

Bring PHY support for the Armada8k driver.

The Armada8k IP only supports x1, x2 or x4 link widths. Iterate over
the DT 'phys' entries and configure them one by one. Use
phy_set_mode_ext() to make use of the submode parameter (initially
introduced for Ethernet modes). For PCI configuration, let the submode
be the width (1, 2, 4, etc) so that the PHY driver knows how many
lanes are bundled. Do not error out in case of error for compatibility
reasons.
Signed-off-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NThomas Petazzoni <thomas.petazzoni@bootlin.com>

Currently, there is only a 1 ms sleep after asserting PERST.

Reading the datasheets for different endpoints, some require PERST to be
asserted for 10 ms in order for the endpoint to perform a reset, others
require it to be asserted for 50 ms.

Several SoCs using this driver uses PCIe Mini Card, where we don't know
what endpoint will be plugged in.

The PCI Express Card Electromechanical Specification r2.0, section
2.2, "PERST# Signal" specifies:

"On power up, the deassertion of PERST# is delayed 100 ms (TPVPERL) from
the power rails achieving specified operating limits."

Add a sleep of 100 ms before deasserting PERST, in order to ensure that
we are compliant with the spec.

Fixes: 82a82383 ("PCI: qcom: Add Qualcomm PCIe controller driver")
Signed-off-by: NNiklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: NStanimir Varbanov <svarbanov@mm-sol.com>
Cc: stable@vger.kernel.org # 4.5+

The QCS404 platform contains a PCIe version 2.4.0 controller and a
Qualcomm PCIe2 PHY. The driver already supports version 2.4.0, for the
IPQ4019, but this support touches clocks and resets related to the PHY
as well and there's no upstream driver for the PHY.

On QCS404 we must initialize the PHY, so a separate PHY driver is
implemented to take care of this and the controller driver is updated to
not require the PHY related resources. This is done by relying on the
fact that operations in both the clock and reset framework are NOPs when
passed NULL, so we can isolate this change to only the
qcom_pcie_get_resources_2_4_0() function.

For QCS404 we also need to enable the AHB (iface) clock, in order to
access the register space of the controller, but as this is not part of
the IPQ4019 DT binding this is only added for new users of the 2.4.0
controller.
Signed-off-by: NBjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NNiklas Cassel <niklas.cassel@linaro.org>
Reviewed-by: NVinod Koul <vkoul@kernel.org>
Acked-by: NStanimir Varbanov <svarbanov@mm-sol.com>

Before introducing the QCS404 platform, which uses the same PCIe
controller as IPQ4019, migrate this to use the bulk clock API, in order
to make the error paths slighly cleaner.
Signed-off-by: NBjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NNiklas Cassel <niklas.cassel@linaro.org>
Reviewed-by: NVinod Koul <vkoul@kernel.org>
Acked-by: NStanimir Varbanov <svarbanov@mm-sol.com>

Establishing a PCIe link can take a while; allow asynchronous probing so
that link establishment can happen in the background while other devices
are being probed.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NFabio Estevam <festevam@gmail.com>

Currently DWC host does not support the remove callback, but nothing
prevents us from supporting it.

Save the root bus for clean up work in driver remove code paths to allow
DWC host drivers to implement their remove hook as, eg:

  static int foo_pcie_remove(struct platform_device *pdev)
  {
    ...
    pci_stop_root_bus(pp->root_bus);
    pci_remove_root_bus(pp->root_bus);
    dw_pcie_free_msi(pp);
    ...
  }
Signed-off-by: NJisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NGustavo Pimentel <gustavo.pimentel@synopsys.com>

Use devm_pci_alloc_host_bridge() to simplify the error code path.  This
also fixes a leak in the dw_pcie_host_init() error path.
Signed-off-by: NJisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NGustavo Pimentel <gustavo.pimentel@synopsys.com>
CC: stable@vger.kernel.org	# v4.13+

If we ever did MSI-related initializations, we need to call
dw_pcie_free_msi() in the error code path.

Remove the IS_ENABLED(CONFIG_PCI_MSI) check for MSI init because
pci_msi_enabled() already has a stub for !CONFIG_PCI_MSI.
Signed-off-by: NJisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NGustavo Pimentel <gustavo.pimentel@synopsys.com>

To avoid a memory leak, free the page allocated for MSI IRQ in
dw_pcie_free_msi().
Signed-off-by: NJisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NGustavo Pimentel <gustavo.pimentel@synopsys.com>

Check msi_irq variable before calling irq_set_chained_handler() and
irq_set_handler_data(), lest we call those functions for an invalid MSI
IRQ.
Signed-off-by: NJisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NGustavo Pimentel <gustavo.pimentel@synopsys.com>

Move the device class fudge to a proper fixup function, and remove
qcom_pcie_rd_own_conf() which has become useless.

dw_pcie_setup_rc() already did the right thing, but it's broken
on older qcom chips, such as 8064.
Signed-off-by: NMarc Gonzalez <marc.w.gonzalez@free.fr>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NStanimir Varbanov <svarbanov@mm-sol.com>

Certain platforms like K2G reguires the outbound ATU window to be
aligned. The alignment size is already present in mem->page_size.
Use the alignment size present in mem->page_size to configure an
aligned ATU window. In order to raise an interrupt, CPU has to write
to address offset from the start of the window unlike before where
writes were always to the beginning of the ATU window.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Configure the Resizable BAR capability to advertise the smallest size
(1MB) for a couple of reasons:

- Host side resource allocation of BAR fails for larger sizes
- Endpoint function driver does not allocate memory for all supported
  sizes in the Resizable BAR capability.

If and when there is a usecase required to add more flexibility using
the Resizable BAR capability, this can be revisited.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
[lorenzo.pieralisi@arm.com: updated commit log]
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Add PCIe EP support for AM654x Platforms in pci-keystone.c

Link: https://lore.kernel.org/linux-pci/20190325093947.32633-15-kishon@ti.com/Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
[lorenzo.pieralisi@arm.com: made dev_vdbg() call a comment]
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

imx6_pcie_enable_ref_clk() is never called in atomic context, so
there's no need to use udelay(). Replace it with usleep_range().
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org

Now that driver data has flags variable that can be used to indicate
quirks/features supported we can switch the code to use it instead of
having a special function that does so based on variant alone. No
functional change intended.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org

PHY registers on i.MX6 are 16-bit wide, so we can get rid of explicit
masking if we restrict pcie_phy_read()/pcie_phy_write() to use 'u16'
instead of 'int'. No functional change intended.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org

Simplify pcie_phy_poll_ack() by incorporating shifting into constant
definition and convert the code to use 'bool'. No functional change
intended.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org

Simplify the code by incorporating left shifts into constant
definitions as well as using FIELD_PREP/GENMASK. No functional change
intended.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org

Avoid using explicit left shifts and convert various definitions to
use BIT() instead. No functional change intended.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org

Both pcie-designware.c and pci-imx6.c contain custom definitions for
PHY debug registers R0/R1 and on top of that there's already a
definition for R0 in pcie-designware.h. Move all of the definitions to
pcie-designware.h. No functional change intended.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org

Code using these constants was removed in commit a7128072 ("PCI:
imx6: Remove LTSSM disable workaround"). No functional change
intended.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org

Change error code from -EINVAL to -ETIMEDOUT in
imx6_pcie_wait_for_speed_change() since that error code seems more
appropriate.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org

All calls to imx6_pcie_wait_for_link() share the same error path and
the state of PHY debug registers will already be printed there, so
there's no real reason we can't just use dw_pcie_wait_for_link(). Drop
imx6_pcie_wait_for_link() and replace it with dw_pcie_wait_for_link().
Suggested-by: NLucas Stach <l.stach@pengutronix.de>
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org

Make use of regmap_read_poll_timeout() to simplify
imx7d_pcie_wait_for_phy_pll_lock(). No functional change intended.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org

Add driver for Amazon's Annapurna Labs PCIe host controller.  The
controller is based on DesignWare's IP.

The controller doesn't support accessing the Root Port's config space via
ECAM, so we obtain its base address via an AMZN0001 device.

Furthermore, the DesignWare PCIe controller doesn't filter out config
transactions sent to devices 1 and up on its bus, so they are filtered by
the driver.

All subordinate buses do support ECAM access.

Implementing specific PCI config access functions involves:
 - Adding an init function to obtain the Root Port's base address from
   an AMZN0001 device.
 - Adding a new entry in the MCFG quirk array.

[bhelgaas: Note that there is no Kconfig option for this driver because it
is only intended for use with the generic ACPI host bridge driver.  This
driver is only needed because the DesignWare IP doesn't completely support
ECAM access to the root bus.]

Link: https://lore.kernel.org/lkml/1553774276-24675-1-git-send-email-jonnyc@amazon.comCo-developed-by: NVladimir Aerov <vaerov@amazon.com>
Signed-off-by: NJonathan Chocron <jonnyc@amazon.com>
Signed-off-by: NVladimir Aerov <vaerov@amazon.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NDavid Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Certain platforms like TI's AM654 do not have aseparate address space for
dbi2 instead they are accessed using the same address space as dbi
with some configuration bit set. In order to support such platforms,
add callbacks for accessing dbi2 address space.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

commit beb4641a ("PCI: dwc: Add MSI-X callbacks handler") while
adding MSI-X callback handler, introduced dw_pcie_ep_find_capability()
and __dw_pcie_ep_find_next_cap() for finding the MSI and MSIX capability.

However if MSI or MSIX capability is the last capability (i.e there are
no additional items in the capabilities list and the Next Capability
Pointer is set to '0'), __dw_pcie_ep_find_next_cap will return '0'
even though MSI or MSIX capability may be present because of
incorrect ordering of the "next_cap_ptr" check. Fix it.

Fixes: beb4641a ("PCI: dwc: Add MSI-X callbacks handler")
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Add const qualifier to struct dw_pcie_ep_ops member of
struct dw_pcie_ep.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>

PCIe in TI's AM654 devices is by default configured to work in GEN3 mode.

However PCIe does not work reliably in GEN3 mode because of SERDES
configuration.

Add support to set the link speed to GEN1, GEN2 or GEN3 based on
"max-link-speed" DT property with GEN2 as the default speed if
"max-link-speed" is absent.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>