Merge tag 'pci-v5.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

Pull PCI updates from Bjorn Helgaas:
 "Enumeration:
   - Remove unnecessary locking around _OSC (Bjorn Helgaas)
   - Clarify message about _OSC failure (Bjorn Helgaas)
   - Remove notification of PCIe bandwidth changes (Bjorn Helgaas)
   - Tidy checking of syscall user config accessors (Heiner Kallweit)

  Resource management:
   - Decline to resize resources if boot config must be preserved (Ard
     Biesheuvel)
   - Fix pci_register_io_range() memory leak (Geert Uytterhoeven)

  Error handling (Keith Busch):
   - Clear error status from the correct device
   - Retain error recovery status so drivers can use it after reset
   - Log the type of Port (Root or Switch Downstream) that we reset
   - Always request a reset for Downstream Ports in frozen state

  Endpoint framework and NTB (Kishon Vijay Abraham I):
   - Make *_get_first_free_bar() take into account 64 bit BAR
   - Add helper API to get the 'next' unreserved BAR
   - Make *_free_bar() return error codes on failure
   - Remove unused pci_epf_match_device()
   - Add support to associate secondary EPC with EPF
   - Add support in configfs to associate two EPCs with EPF
   - Add pci_epc_ops to map MSI IRQ
   - Add pci_epf_ops to expose function-specific attrs
   - Allow user to create sub-directory of 'EPF Device' directory
   - Implement ->msi_map_irq() ops for cadence
   - Configure LM_EP_FUNC_CFG based on epc->function_num_map for cadence
   - Add EP function driver to provide NTB functionality
   - Add support for EPF PCI Non-Transparent Bridge
   - Add specification for PCI NTB function device
   - Add PCI endpoint NTB function user guide
   - Add configfs binding documentation for pci-ntb endpoint function

  Broadcom STB PCIe controller driver:
   - Add support for BCM4908 and external PERST# signal controller
     (Rafał Miłecki)

  Cadence PCIe controller driver:
   - Retrain Link to work around Gen2 training defect (Nadeem Athani)
   - Fix merge botch in cdns_pcie_host_map_dma_ranges() (Krzysztof
     Wilczyński)

  Freescale Layerscape PCIe controller driver:
   - Add LX2160A rev2 EP mode support (Hou Zhiqiang)
   - Convert to builtin_platform_driver() (Michael Walle)

  MediaTek PCIe controller driver:
   - Fix OF node reference leak (Krzysztof Wilczyński)

  Microchip PolarFlare PCIe controller driver:
   - Add Microchip PolarFire PCIe controller driver (Daire McNamara)

  Qualcomm PCIe controller driver:
   - Use PHY_REFCLK_USE_PAD only for ipq8064 (Ansuel Smith)
   - Add support for ddrss_sf_tbu clock for sm8250 (Dmitry Baryshkov)

  Renesas R-Car PCIe controller driver:
   - Drop PCIE_RCAR config option (Lad Prabhakar)
   - Always allocate MSI addresses in 32bit space (Marek Vasut)

  Rockchip PCIe controller driver:
   - Add FriendlyARM NanoPi M4B DT binding (Chen-Yu Tsai)
   - Make 'ep-gpios' DT property optional (Chen-Yu Tsai)

  Synopsys DesignWare PCIe controller driver:
   - Work around ECRC configuration hardware defect (Vidya Sagar)
   - Drop support for config space in DT 'ranges' (Rob Herring)
   - Change size to u64 for EP outbound iATU (Shradha Todi)
   - Add upper limit address for outbound iATU (Shradha Todi)
   - Make dw_pcie ops optional (Jisheng Zhang)
   - Remove unnecessary dw_pcie_ops from al driver (Jisheng Zhang)

  Xilinx Versal CPM PCIe controller driver:
   - Fix OF node reference leak (Pan Bian)

  Miscellaneous:
   - Remove tango host controller driver (Arnd Bergmann)
   - Remove IRQ handler & data together (altera-msi, brcmstb, dwc)
     (Martin Kaiser)
   - Fix xgene-msi race in installing chained IRQ handler (Martin
     Kaiser)
   - Apply CONFIG_PCI_DEBUG to entire drivers/pci hierarchy (Junhao He)
   - Fix pci-bridge-emul array overruns (Russell King)
   - Remove obsolete uses of WARN_ON(in_interrupt()) (Sebastian Andrzej
     Siewior)"

* tag 'pci-v5.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (69 commits)
  PCI: qcom: Use PHY_REFCLK_USE_PAD only for ipq8064
  PCI: qcom: Add support for ddrss_sf_tbu clock
  dt-bindings: PCI: qcom: Document ddrss_sf_tbu clock for sm8250
  PCI: al: Remove useless dw_pcie_ops
  PCI: dwc: Don't assume the ops in dw_pcie always exist
  PCI: dwc: Add upper limit address for outbound iATU
  PCI: dwc: Change size to u64 for EP outbound iATU
  PCI: dwc: Drop support for config space in 'ranges'
  PCI: layerscape: Convert to builtin_platform_driver()
  PCI: layerscape: Add LX2160A rev2 EP mode support
  dt-bindings: PCI: layerscape: Add LX2160A rev2 compatible strings
  PCI: dwc: Work around ECRC configuration issue
  PCI/portdrv: Report reset for frozen channel
  PCI/AER: Specify the type of Port that was reset
  PCI/ERR: Retain status from error notification
  PCI/AER: Clear AER status from Root Port when resetting Downstream Port
  PCI/ERR: Clear status of the reporting device
  dt-bindings: arm: rockchip: Add FriendlyARM NanoPi M4B
  PCI: rockchip: Make 'ep-gpios' DT property optional
  Documentation: PCI: Add PCI endpoint NTB function user guide
  ...

73 files changed, 5543 insertions, 781 deletions

diff --git a/Documentation/PCI/endpoint/function/binding/pci-ntb.rst b/Documentation/PCI/endpoint/function/binding/pci-ntb.rst
new file mode 100644
index 000000000000..40253d3d5163
--- /dev/null
+++ b/Documentation/PCI/endpoint/function/binding/pci-ntb.rst
@@ -0,0 +1,38 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==========================
+PCI NTB Endpoint Function
+==========================
+
+1) Create a subdirectory to pci_epf_ntb directory in configfs.
+
+Standard EPF Configurable Fields:
+
+================   ===========================================================
+vendorid	   should be 0x104c
+deviceid	   should be 0xb00d for TI's J721E SoC
+revid		   don't care
+progif_code	   don't care
+subclass_code	   should be 0x00
+baseclass_code	   should be 0x5
+cache_line_size	   don't care
+subsys_vendor_id   don't care
+subsys_id	   don't care
+interrupt_pin	   don't care
+msi_interrupts	   don't care
+msix_interrupts	   don't care
+================   ===========================================================
+
+2) Create a subdirectory to directory created in 1
+
+NTB EPF specific configurable fields:
+
+================   ===========================================================
+db_count	   Number of doorbells; default = 4
+mw1     	   size of memory window1
+mw2     	   size of memory window2
+mw3     	   size of memory window3
+mw4     	   size of memory window4
+num_mws     	   Number of memory windows; max = 4
+spad_count     	   Number of scratchpad registers; default = 64
+================   ===========================================================
diff --git a/Documentation/PCI/endpoint/index.rst b/Documentation/PCI/endpoint/index.rst
index 4ca7439fbfc9..38ea1f604b6d 100644
--- a/Documentation/PCI/endpoint/index.rst
+++ b/Documentation/PCI/endpoint/index.rst
@@ -11,5 +11,8 @@ PCI Endpoint Framework
    pci-endpoint-cfs
    pci-test-function
    pci-test-howto
+   pci-ntb-function
+   pci-ntb-howto
 
    function/binding/pci-test
+   function/binding/pci-ntb
diff --git a/Documentation/PCI/endpoint/pci-endpoint-cfs.rst b/Documentation/PCI/endpoint/pci-endpoint-cfs.rst
index 1bbd81ed06c8..696f8eeb4738 100644
--- a/Documentation/PCI/endpoint/pci-endpoint-cfs.rst
+++ b/Documentation/PCI/endpoint/pci-endpoint-cfs.rst
@@ -68,6 +68,16 @@ created)
 				... subsys_vendor_id
 				... subsys_id
 				... interrupt_pin
+                                ... primary/
+			                ... <Symlink EPC Device1>/
+                                ... secondary/
+			                ... <Symlink EPC Device2>/
+
+If an EPF device has to be associated with 2 EPCs (like in the case of
+Non-transparent bridge), symlink of endpoint controller connected to primary
+interface should be added in 'primary' directory and symlink of endpoint
+controller connected to secondary interface should be added in 'secondary'
+directory.
 
 EPC Device
 ==========
diff --git a/Documentation/PCI/endpoint/pci-ntb-function.rst b/Documentation/PCI/endpoint/pci-ntb-function.rst
new file mode 100644
index 000000000000..3b9d836a4924
--- /dev/null
+++ b/Documentation/PCI/endpoint/pci-ntb-function.rst
@@ -0,0 +1,348 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=================
+PCI NTB Function
+=================
+
+:Author: Kishon Vijay Abraham I <kishon@ti.com>
+
+PCI Non-Transparent Bridges (NTB) allow two host systems to communicate
+with each other by exposing each host as a device to the other host.
+NTBs typically support the ability to generate interrupts on the remote
+machine, expose memory ranges as BARs, and perform DMA.  They also support
+scratchpads, which are areas of memory within the NTB that are accessible
+from both machines.
+
+PCI NTB Function allows two different systems (or hosts) to communicate
+with each other by configuring the endpoint instances in such a way that
+transactions from one system are routed to the other system.
+
+In the below diagram, PCI NTB function configures the SoC with multiple
+PCI Endpoint (EP) instances in such a way that transactions from one EP
+controller are routed to the other EP controller. Once PCI NTB function
+configures the SoC with multiple EP instances, HOST1 and HOST2 can
+communicate with each other using SoC as a bridge.
+
+.. code-block:: text
+
+    +-------------+                                   +-------------+
+    |             |                                   |             |
+    |    HOST1    |                                   |    HOST2    |
+    |             |                                   |             |
+    +------^------+                                   +------^------+
+           |                                                 |
+           |                                                 |
+ +---------|-------------------------------------------------|---------+
+ |  +------v------+                                   +------v------+  |
+ |  |             |                                   |             |  |
+ |  |     EP      |                                   |     EP      |  |
+ |  | CONTROLLER1 |                                   | CONTROLLER2 |  |
+ |  |             <----------------------------------->             |  |
+ |  |             |                                   |             |  |
+ |  |             |                                   |             |  |
+ |  |             |  SoC With Multiple EP Instances   |             |  |
+ |  |             |  (Configured using NTB Function)  |             |  |
+ |  +-------------+                                   +-------------+  |
+ +---------------------------------------------------------------------+
+
+Constructs used for Implementing NTB
+====================================
+
+	1) Config Region
+	2) Self Scratchpad Registers
+	3) Peer Scratchpad Registers
+	4) Doorbell (DB) Registers
+	5) Memory Window (MW)
+
+
+Config Region:
+--------------
+
+Config Region is a construct that is specific to NTB implemented using NTB
+Endpoint Function Driver. The host and endpoint side NTB function driver will
+exchange information with each other using this region. Config Region has
+Control/Status Registers for configuring the Endpoint Controller. Host can
+write into this region for configuring the outbound Address Translation Unit
+(ATU) and to indicate the link status. Endpoint can indicate the status of
+commands issued by host in this region. Endpoint can also indicate the
+scratchpad offset and number of memory windows to the host using this region.
+
+The format of Config Region is given below. All the fields here are 32 bits.
+
+.. code-block:: text
+
+	+------------------------+
+	|         COMMAND        |
+	+------------------------+
+	|         ARGUMENT       |
+	+------------------------+
+	|         STATUS         |
+	+------------------------+
+	|         TOPOLOGY       |
+	+------------------------+
+	|    ADDRESS (LOWER 32)  |
+	+------------------------+
+	|    ADDRESS (UPPER 32)  |
+	+------------------------+
+	|           SIZE         |
+	+------------------------+
+	|   NO OF MEMORY WINDOW  |
+	+------------------------+
+	|  MEMORY WINDOW1 OFFSET |
+	+------------------------+
+	|       SPAD OFFSET      |
+	+------------------------+
+	|        SPAD COUNT      |
+	+------------------------+
+	|      DB ENTRY SIZE     |
+	+------------------------+
+	|         DB DATA        |
+	+------------------------+
+	|            :           |
+	+------------------------+
+	|            :           |
+	+------------------------+
+	|         DB DATA        |
+	+------------------------+
+
+
+  COMMAND:
+
+	NTB function supports three commands:
+
+	  CMD_CONFIGURE_DOORBELL (0x1): Command to configure doorbell. Before
+	invoking this command, the host should allocate and initialize
+	MSI/MSI-X vectors (i.e., initialize the MSI/MSI-X Capability in the
+	Endpoint). The endpoint on receiving this command will configure
+	the outbound ATU such that transactions to Doorbell BAR will be routed
+	to the MSI/MSI-X address programmed by the host. The ARGUMENT
+	register should be populated with number of DBs to configure (in the
+	lower 16 bits) and if MSI or MSI-X should be configured (BIT 16).
+
+	  CMD_CONFIGURE_MW (0x2): Command to configure memory window (MW). The
+	host invokes this command after allocating a buffer that can be
+	accessed by remote host. The allocated address should be programmed
+	in the ADDRESS register (64 bit), the size should be programmed in
+	the SIZE register and the memory window index should be programmed
+	in the ARGUMENT register. The endpoint on receiving this command
+	will configure the outbound ATU such that transactions to MW BAR
+	are routed to the address provided by the host.
+
+	  CMD_LINK_UP (0x3): Command to indicate an NTB application is
+	bound to the EP device on the host side. Once the endpoint
+	receives this command from both the hosts, the endpoint will
+	raise a LINK_UP event to both the hosts to indicate the host
+	NTB applications can start communicating with each other.
+
+  ARGUMENT:
+
+	The value of this register is based on the commands issued in
+	command register. See COMMAND section for more information.
+
+  TOPOLOGY:
+
+	Set to NTB_TOPO_B2B_USD for Primary interface
+	Set to NTB_TOPO_B2B_DSD for Secondary interface
+
+  ADDRESS/SIZE:
+
+	Address and Size to be used while configuring the memory window.
+	See "CMD_CONFIGURE_MW" for more info.
+
+  MEMORY WINDOW1 OFFSET:
+
+	Memory Window 1 and Doorbell registers are packed together in the
+	same BAR. The initial portion of the region will have doorbell
+	registers and the latter portion of the region is for memory window 1.
+	This register will specify the offset of the memory window 1.
+
+  NO OF MEMORY WINDOW:
+
+	Specifies the number of memory windows supported by the NTB device.
+
+  SPAD OFFSET:
+
+	Self scratchpad region and config region are packed together in the
+	same BAR. The initial portion of the region will have config region
+	and the latter portion of the region is for self scratchpad. This
+	register will specify the offset of the self scratchpad registers.
+
+  SPAD COUNT:
+
+	Specifies the number of scratchpad registers supported by the NTB
+	device.
+
+  DB ENTRY SIZE:
+
+	Used to determine the offset within the DB BAR that should be written
+	in order to raise doorbell. EPF NTB can use either MSI or MSI-X to
+	ring doorbell (MSI-X support will be added later). MSI uses same
+	address for all the interrupts and MSI-X can provide different
+	addresses for different interrupts. The MSI/MSI-X address is provided
+	by the host and the address it gives is based on the MSI/MSI-X
+	implementation supported by the host. For instance, ARM platform
+	using GIC ITS will have the same MSI-X address for all the interrupts.
+	In order to support all the combinations and use the same mechanism
+	for both MSI and MSI-X, EPF NTB allocates a separate region in the
+	Outbound Address Space for each of the interrupts. This region will
+	be mapped to the MSI/MSI-X address provided by the host. If a host
+	provides the same address for all the interrupts, all the regions
+	will be translated to the same address. If a host provides different
+	addresses, the regions will be translated to different addresses. This
+	will ensure there is no difference while raising the doorbell.
+
+  DB DATA:
+
+	EPF NTB supports 32 interrupts, so there are 32 DB DATA registers.
+	This holds the MSI/MSI-X data that has to be written to MSI address
+	for raising doorbell interrupt. This will be populated by EPF NTB
+	while invoking CMD_CONFIGURE_DOORBELL.
+
+Scratchpad Registers:
+---------------------
+
+  Each host has its own register space allocated in the memory of NTB endpoint
+  controller. They are both readable and writable from both sides of the bridge.
+  They are used by applications built over NTB and can be used to pass control
+  and status information between both sides of a device.
+
+  Scratchpad registers has 2 parts
+	1) Self Scratchpad: Host's own register space
+	2) Peer Scratchpad: Remote host's register space.
+
+Doorbell Registers:
+-------------------
+
+  Doorbell Registers are used by the hosts to interrupt each other.
+
+Memory Window:
+--------------
+
+  Actual transfer of data between the two hosts will happen using the
+  memory window.
+
+Modeling Constructs:
+====================
+
+There are 5 or more distinct regions (config, self scratchpad, peer
+scratchpad, doorbell, one or more memory windows) to be modeled to achieve
+NTB functionality. At least one memory window is required while more than
+one is permitted. All these regions should be mapped to BARs for hosts to
+access these regions.
+
+If one 32-bit BAR is allocated for each of these regions, the scheme would
+look like this:
+
+======  ===============
+BAR NO  CONSTRUCTS USED
+======  ===============
+BAR0    Config Region
+BAR1    Self Scratchpad
+BAR2    Peer Scratchpad
+BAR3    Doorbell
+BAR4    Memory Window 1
+BAR5    Memory Window 2
+======  ===============
+
+However if we allocate a separate BAR for each of the regions, there would not
+be enough BARs for all the regions in a platform that supports only 64-bit
+BARs.
+
+In order to be supported by most of the platforms, the regions should be
+packed and mapped to BARs in a way that provides NTB functionality and
+also makes sure the host doesn't access any region that it is not supposed
+to.
+
+The following scheme is used in EPF NTB Function:
+
+======  ===============================
+BAR NO  CONSTRUCTS USED
+======  ===============================
+BAR0    Config Region + Self Scratchpad
+BAR1    Peer Scratchpad
+BAR2    Doorbell + Memory Window 1
+BAR3    Memory Window 2
+BAR4    Memory Wind