If the PCIe link is down, return zero from imx6_pcie_start_link() so the
driver will probe successfully.

Link: https://lore.kernel.org/r/1657783869-19194-13-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

Move regulator enable out of imx6_pcie_deassert_core_reset(), since the
regulator_enable() has nothing to do with imx6_pcie_deassert_core_reset().

Link: https://lore.kernel.org/r/1657783869-19194-12-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

The driver should undo any enables it did itself. The regulator disable
shouldn't be basing decisions on regulator_is_enabled().

Move the regulator_disable to the suspend function, turn off regulator when
the system is in suspend mode.

Link: https://lore.kernel.org/r/1657783869-19194-11-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Call imx6_pcie_host_init() instead of duplicating codes in resume.  Note
that this also means we do MPLL setup again during resume, which we didn't
do before.

[bhelgaas: add MPLL setup note, pointed out by Lucas]
Link: https://lore.kernel.org/r/1657783869-19194-10-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

When disabling PCIe clocks, disable i.MX6QDL ref clock too.

Link: https://lore.kernel.org/r/1657783869-19194-9-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

Since dw_pcie_host_init() checks for errors from ops->host_init(),
check for errors when enabling power regulators and clocks and return them.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/1657783869-19194-8-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

Encapsulate the i.MX PCIe clock enable operations into one standalone
function, imx6_pcie_clk_enable().  No functional change intended.

[bhelgaas: split pure code moves into separate patches]
Link: https://lore.kernel.org/r/1657783869-19194-7-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

The PCIe ref clocks are specific to different variants.  The enables are
already split out into imx6_pcie_enable_ref_clk(), but the disables were
combined with the more generic bus/phy/pcie clock disables in
imx6_pcie_clk_disable().

Split out the variant-specific disables into imx6_pcie_disable_ref_clk() to
match imx6_pcie_enable_ref_clk().

No functional change intended.

Link: https://lore.kernel.org/r/1657783869-19194-6-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>

Move imx6_pcie_clk_disable() earlier to be near other clock-related
functions.  No functional change intended.

[bhelgaas: reorder patch so pure moves are earlier]
Link: https://lore.kernel.org/r/1657783869-19194-5-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

Move imx6_pcie_enable_ref_clk() earlier so it's not in the middle between
imx6_pcie_assert_core_reset() and imx6_pcie_deassert_core_reset().  No
functional change intended.

Link: https://lore.kernel.org/r/1657783869-19194-4-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>

Collect imx6_pcie_init_phy(), imx7d_pcie_wait_for_phy_pll_lock(), and
imx6_setup_phy_mpll() earlier with other PHY-related code.  No functional
change intended.

Link: https://lore.kernel.org/r/1657783869-19194-3-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>

Move imx6_pcie_grp_offset() and imx6_pcie_configure_type() earlier in the
file since they depend on nothing and are used by several other functions
that will be moved earlier.  No functional change intended.

Link: https://lore.kernel.org/r/1657783869-19194-2-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>

Replace SET_NOIRQ_SYSTEM_SLEEP_PM_OPS() with NOIRQ_SYSTEM_SLEEP_PM_OPS(),
which has the advantage that the compiler always sees the PM callbacks as
referenced, so they don't need to be wrapped with "#ifdef CONFIG_PM_SLEEP"
or tagged with "__maybe_unused" to avoid "defined but not used" warnings.

See 1a3c7bb0 ("PM: core: Add new *_PM_OPS macros, deprecate old ones").
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

On Qualcomm platforms each group of 32 MSI vectors is routed to the
separate GIC interrupt. Document mapping of additional interrupts.

Link: https://lore.kernel.org/r/20220707134733.2436629-6-dmitry.baryshkov@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Acked-by: Stanimir Varbanov <svarbanov@mm-sol.com>

On some Qualcomm platforms each group of 32 MSI vectors is routed to a
separate GIC interrupt. Implement support for such configurations by
parsing "msi0" ... "msiX" interrupts and attaching them to the chained
handler.

Note that if DT doesn't list an array of MSI interrupts and uses a single
"msi" IRQ, the driver will limit the number of supported MSI vectors to 32.

Link: https://lore.kernel.org/r/20220707134733.2436629-5-dmitry.baryshkov@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

The Qualcomm DWC PCIe controller supports more than 32 MSI interrupts, but
they are routed to separate interrupts in groups of 32 vectors. To support
this configuration, change the msi_irq field to an array. Let the DWC core
handle all interrupts that were set in this array.

[bhelgaas: reorder, drop "irq" temporary to make patch cleaner]
Link: https://lore.kernel.org/r/20220707134733.2436629-3-dmitry.baryshkov@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Split handling of MSI host IRQs to a separate dw_pcie_msi_host_init()
function. The code is complex enough to warrant a separate function.

[bhelgaas: reorder patch earlier]
Link: https://lore.kernel.org/r/20220707134733.2436629-4-dmitry.baryshkov@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

The dwc-based drivers set pp->msi_irq to -ENODEV if they do not want the
dwc core to do anything with pp->msi_irq.

dw_pcie_host_init() sets the handler and data when "pp->msi_irq > 0", so
use the same condition when removing the handler and data in
dw_pcie_free_msi().

Link: https://lore.kernel.org/r/20220707134733.2436629-2-dmitry.baryshkov@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Use devm_bitmap_zalloc() instead of hand-writing them.

It is less verbose and it improves the semantic.

Link: https://lore.kernel.org/r/bc6586a603abc0db7d4531308b698fbe7a6d7083.1657375829.git.christophe.jaillet@wanadoo.frSigned-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

As of 07940c36 ("PCI: dwc: Fix MSI page leakage in suspend/resume"),
the PCIe designware host driver has been using the driver data allocation
for the msi_msg DMA mapping which can result in a DMA_MAPPING_ERROR due to
the DMA overflow check in dma_direct_map_page() when the address is greater
than 32 bits (reported in [1]). The commit was trying to address a memory
leak on suspend/resume by moving the MSI mapping to dw_pcie_host_init(),
but subsequently dropped the page allocation thinking it wasn't needed.

To fix the DMA mapping issue as well as make msi_msg DMA'able, switch back
to allocating a 32-bit page for the msi_msg. To avoid the suspend/resume
leak, allocate the page in dw_pcie_host_init() since that shouldn't be
called during suspend/resume.

[1] https://lore.kernel.org/all/Yo0soniFborDl7+C@google.com/Signed-off-by: Will McVicker <willmcvicker@google.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>

Make the DWC PCIe RC/EP safer and more verbose for invalid or failed
inbound and outbound iATU window setups.  Silently ignoring iATU regions
setup errors may cause unpredictable errors. For instance if a cfg or IO
window fails to be activated, then any CFG/IO requested won't reach target
PCIe devices and the corresponding accessors will return platform-specific
random values.

[bhelgaas: trim commit log]
Link: https://lore.kernel.org/r/20220624143947.8991-15-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Make __dw_pcie_prog_outbound_atu() check the requested region base and size
against what the hardware can support.  Return error if the region is not
correctly aligned or of a supported size.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143947.8991-14-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

The DWC PCIe RC/EP/DM IP core configuration parameters determine the number
of inbound and outbound iATU windows, alignment requirements (which is also
the minimum window size), minimum and maximum sizes.  If internal ATU is
enabled, the former settings are determined by CX_ATU_MIN_REGION_SIZE; the
latter are determined by CX_ATU_MAX_REGION_SIZE.

Determine the required alignment and maximum size supported by the
controller and log it to help verify whether the requested inbound or
outbound memory mappings can be fully created.

Note 1. The extended iATU regions have been supported since DWC PCIe
v4.60a. There is no need in testing the upper limit register availability
for the older cores.

Note 2. The regions alignment is determined with using the fls() method
since the lower four bits of the ATU Limit register can be occupied with
the Circular Buffer Increment setting, which can be initialized with zeros.

Link: https://lore.kernel.org/r/20220624143947.8991-13-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Previously __dw_pcie_prog_outbound_atu() duplicated a lot of code between
the iatu_unroll_enabled version and the PCIE_ATU_VIEWPORT version:

  __dw_pcie_prog_outbound_atu
    if (iatu_unroll_enabled)
      dw_pcie_prog_outbound_atu_unroll
        dw_pcie_writel_ob_unroll(PCIE_ATU_UNR_LOWER_BASE, ...)
        dw_pcie_writel_ob_unroll(PCIE_ATU_UNR_UPPER_BASE, ...)
        ...
      return
    dw_pcie_writel_dbi(PCIE_ATU_VIEWPORT, ...)
    dw_pcie_writel_dbi(PCIE_ATU_LOWER_BASE, ...)
    dw_pcie_writel_dbi(PCIE_ATU_UPPER_BASE, ...)
    ...

Unify those by pushing the unroll address computation and viewport
selection down into dw_pcie_writel_atu() so we can use the same
dw_pcie_writel_atu_ob() accessor for both paths:

  __dw_pcie_prog_outbound_atu
    dw_pcie_writel_atu_ob(PCIE_ATU_LOWER_BASE, ...)
      dw_pcie_writel_atu
        dw_pcie_select_atu                      # new
          if (iatu_unroll_enabled)
            return pci->atu_base + PCIE_ATU_UNROLL_BASE(...)
          dw_pcie_writel_dbi(PCIE_ATU_VIEWPORT, ...)
          return pci->atu_base
        dw_pcie_write(base + reg)
      dw_pcie_writel_atu_ob(PCIE_ATU_UPPER_BASE, ...)
      ...

In the non-unroll case, this does involve more MMIO writes to
PCIE_ATU_VIEWPORT, but it's mainly in initialization paths and the code
simplification is significant.

[bhelgaas: commit log, simplify dw_pcie_select_atu()]
Link: https://lore.kernel.org/r/20220624143947.8991-12-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Previously callers of dw_pcie_disable_atu() supplied enum
dw_pcie_region_type (DW_PCIE_REGION_INBOUND, DW_PCIE_REGION_OUTBOUND),
which dw_pcie_disable_atu() converted to the PCIE_ATU_REGION_DIR_IB or
PCIE_ATU_REGION_DIR_OB values needed to program the ATU registers.

Simplify the code by dropping the dw_pcie_region_type enum and passing
PCIE_ATU_REGION_DIR_IB or PCIE_ATU_REGION_DIR_OB directly.

Reorder dw_pcie_disable_atu() arguments to (dir, index) since "index"
indicates an ATU window in the regions of the corresponding direction.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143947.8991-11-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Previously dw_pcie_ep_set_bar() converted the BAR PCI_BASE_ADDRESS_SPACE
bit to the internal dw_pcie_as_type enum (DW_PCIE_AS_MEM, DW_PCIE_AS_IO)
and passed it down to dw_pcie_prog_inbound_atu(), which converted the enum
to the PCIE_ATU_TYPE_MEM/PCIE_ATU_TYPE_IO values needed to program the ATU
registers.

Simplify the code by dropping the dw_pcie_as_type enum and passing
PCIE_ATU_TYPE_MEM or PCIE_ATU_TYPE_IO directly.

Reorder inbound ATU function arguments to match the outbound functions,
with address-related parameters at the end.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143947.8991-10-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

dw_pcie_host_init() calls the dw_pcie_ops.host_init() callback to do
platform-specific host initialization.

Add a dw_pcie_ops.host_deinit() callback to perform the corresponding
cleanups in dw_pcie_host_deinit() and in dw_pcie_host_init() failure paths.

Link: https://lore.kernel.org/r/20220624143947.8991-9-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Since the DW PCIe common code (dw_pcie_version_detect()) now reads the IP
core version directly from the hardware, there is no point manually setting
the version for controllers newer than v4.70a.

Tegra194 only supports v4.90a, so remove the now-superfluous code that sets
struct dw_pcie.version.
Suggested-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220624143947.8991-8-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Since the DW PCIe common code (dw_pcie_version_detect()) now reads the IP
core version directly from the hardware, there is no point manually setting
the version for controllers newer than v4.70a.

Remove the now-superfluous intel-gw code that sets struct dw_pcie.version.
Suggested-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220624143947.8991-7-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Add macros to compare DWC IP core versions:

  dw_pcie_ver_is()
  dw_pcie_ver_is_ge()
  dw_pcie_ver_type_is()
  dw_pcie_ver_type_is_ge()

These are along the lines of DWC3_VER_IS() and dw_spi_ver_is().

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143947.8991-6-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>

Since DWC PCIe v4.70a, the controller version and version type can be read
from the PORT_LOGIC.PCIE_VERSION_OFF and PORT_LOGIC.PCIE_VERSION_TYPE_OFF
registers respectively.

Read the version from those registers and warn if if's different from the
version we got from the device tree.

We can only read the version after platform-specific drivers have done any
DBI-related initialization, such as reference clock activation.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143947.8991-5-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Save the DWC IP core version in the same format as the
PORT_LOGIC.PCIE_VERSION_OFF register, similar to what other drivers for DWC
IP do (dw_spi_hw_init(), dwc3_core_is_valid(), stmmac_hwif_init()).

[bhelgaas: trim commit log]
Link: https://lore.kernel.org/r/20220624143947.8991-4-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Previously, dw_pcie_ep_init() did:

  dw_pcie_iatu_detect(pci);
  res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space");
  if (!res)
    return -EINVAL;

The platform_get_resource_byname() can fail, and dw_pcie_iatu_detect()
doesn't depend on the "addr_space" resource, so delay it until afterwards,
i.e.,

  platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space");
  dw_pcie_iatu_detect(pci);

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143947.8991-3-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Printing just "link up" isn't very informative for PCI Express. Even if the
link is up, bus performance can degrade to slower speeds or to narrower
width than both Root Port and its partner is capable of. In that case it
would be handy to know the link specifications as early as possible.

If the link comes up, log the link speed (PCIe generation) and width.

Link: https://lore.kernel.org/r/20220624143947.8991-2-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

The dw_plat_pcie_of_match[] forward declaration was required when
dw_plat_pcie_probe() called of_match_device().  5c204204 ("PCI:
designware-plat: Prefer of_device_get_match_data()") replaced that with
of_device_get_match_data(), which no longer needs the declaration.

Drop the unnecessary forward declaration.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143428.8334-19-Sergey.Semin@baikalelectronics.ruTested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>

1d906b22 ("PCI: dwc: Add support for EP mode") added the struct
dw_plat_pcie regmap pointer, but it has never been used.  Remove it.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143428.8334-18-Sergey.Semin@baikalelectronics.ruTested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>

Save the return value in "ret" for all three cases (DW_PCIE_RC_TYPE,
DW_PCIE_EP_TYPE, default) handled by dw_plat_pcie_probe() and return from a
single place.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143428.8334-17-Sergey.Semin@baikalelectronics.ruTested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>

All of the DW PCIe core driver entities except the pcie_port struct have
names with the "dw_" prefix to distinguish local and common PCIe name
spaces, and endpoint-related entities have an "_ep" suffix.

Rename struct pcie_port to dw_pcie_rp to make it more consistent with other
names.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143428.8334-16-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>

The io_cfg_atu_shared flag is set if there is an outbound iATU window used
for both config space accesses and IO port transfers.

Since the flag semantic is purely Root Port specific, it's not used in
either the DW PCIe common code or in the DW PCIe Endpoint driver. Move it
to the struct pcie_port and rename to cfg0_io_shared.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143428.8334-15-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Factor out this pattern:

  if (!pci->ops || !pci->ops->start_link)
    return -EINVAL;

  return pci->ops->start_link(pci);

into a new dw_pcie_start_link() wrapper and do the same for the stop_link()
method.

Note that dw_pcie_ep_start() previously returned -EINVAL if there was no
platform start_link() method, which didn't make much sense since that is
not an error.  It will now return 0 in that case.

As a side-effect, drop the empty start_link() and dummy dw_pcie_ops
instances from the generic DW PCIe and Layerscape EP platform drivers.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143428.8334-14-Sergey.Semin@baikalelectronics.ruSigned-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>