PCI: endpoint: Add PCI Endpoint function driver for MHI bus

Add PCI Endpoint driver for the Qualcomm MHI (Modem Host Interface) bus.

The driver implements the MHI function over PCI in the endpoint device such
as SDX55 modem. The MHI endpoint function driver acts as a controller
driver for the MHI Endpoint stack and carries out all PCI related
functionality.

Link: https://lore.kernel.org/r/20230602114756.36586-9-manivannan.sadhasivam@linaro.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kishon Vijay Abraham I <kishon@kernel.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>

PCI: endpoint: Fix a Kconfig prompt of vNTB driver

vNTB driver and NTB driver have same Kconfig prompt. Changed to make it
distinguishable.

Link: https://lore.kernel.org/r/20230202103832.2038286-1-mie@igel.co.jp
Fixes: e35f56bb0330 ("PCI: endpoint: Support NTB transfer between RC and EP")
Signed-off-by: Shunsuke Mie <mie@igel.co.jp>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>

PCI: endpoint: Fix Kconfig indent style

Change to follow the Kconfig style guide. This patch fixes to use tab
rather than space to indent, while help text is indented an additional
two spaces.

Link: https://lore.kernel.org/r/20220815025006.48167-1-mie@igel.co.jp
Fixes: e35f56bb0330 ("PCI: endpoint: Support NTB transfer between RC and EP")
Signed-off-by: Shunsuke Mie <mie@igel.co.jp>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>

PCI: endpoint: Fix Kconfig dependency

If CONFIG_NTB is not set and CONFIG_PCI_EPF_VNTB is y.

make ARCH=x86_64 CROSS_COMPILE=x86_64-linux-gnu-, will be failed, like this:

drivers/pci/endpoint/functions/pci-epf-vntb.o: In function `epf_ntb_cmd_handler':
pci-epf-vntb.c:(.text+0x95e): undefined reference to `ntb_db_event'
pci-epf-vntb.c:(.text+0xa1f): undefined reference to `ntb_link_event'
pci-epf-vntb.c:(.text+0xa42): undefined reference to `ntb_link_event'
drivers/pci/endpoint/functions/pci-epf-vntb.o: In function `pci_vntb_probe':
pci-epf-vntb.c:(.text+0x1250): undefined reference to `ntb_register_device'

The functions ntb_*() are defined in drivers/ntb/core.c, which need CONFIG_NTB setting y to be build-in.
To fix this build error, add depends on NTB.

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: ff32fac00d97("NTB: EPF: support NTB transfer between PCI RC and EP connection")
Signed-off-by: Ren Zhijie <renzhijie2@huawei.com>
Acked-by: Frank Li <frank.li@nxp.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

PCI: endpoint: Support NTB transfer between RC and EP

Add NTB function driver and virtual PCI Bus and Virtual NTB driver
to implement communication between PCIe Root Port and PCIe EP devices

┌────────────┐ ┌─────────────────────────────────────┐
│ │ │ │
├────────────┤ │ ┌──────────────┤
│ NTB │ │ │ NTB │
│ NetDev │ │ │ NetDev │
├────────────┤ │ ├──────────────┤
│ NTB │ │ │ NTB │
│ Transfer │ │ │ Transfer │
├────────────┤ │ ├──────────────┤
│ │ │ │ │
│ PCI NTB │ │ │ │
│ EPF │ │ │ │
│ Driver │ │ │ PCI Virtual │
│ │ ├───────────────┐ │ NTB Driver │
│ │ │ PCI EP NTB │◄────►│ │
│ │ │ FN Driver │ │ │
├────────────┤ ├───────────────┤ ├──────────────┤
│ │ │ │ │ │
│ PCI Bus │ ◄─────► │ PCI EP Bus │ │ Virtual PCI │
│ │ PCI │ │ │ Bus │
└────────────┘ └───────────────┴──────┴──────────────┘
PCIe Root Port PCI EP

This driver includes 3 parts:
1 PCI EP NTB function driver
2 Virtual PCI bus
3 PCI virtual NTB driver, which is loaded only by above virtual PCI bus

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

PCI: endpoint: Add EP function driver to provide NTB functionality

Add a new endpoint function driver to provide NTB functionality using
multiple PCIe endpoint instances.

[arnd@arndb.de: Select configfs dependency]
[yebin10@huawei.com: Fix unused but set variables]
[geert+renesas@glider.be: Explain NTB in PCI_EPF_NTB help text]

Link: https://lore.kernel.org/r/20210201195809.7342-14-kishon@ti.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: Add SPDX GPL-2.0 when no license was specified

b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to
files with no license") added SPDX GPL-2.0 to several PCI files that
previously contained no license information.

Add SPDX GPL-2.0 to all other PCI files that did not contain any license
information and hence were under the default GPL version 2 license of the
kernel.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PCI: endpoint: Select CRC32 to fix test build error

The PCI endpoint test driver uses crc32_le() so it should select
CRC32. Fixes this build error (when CRC32=m):

drivers/built-in.o: In function `pci_epf_test_cmd_handler':
pci-epf-test.c:(.text+0x2d98d): undefined reference to `crc32_le'

Fixes: 349e7a85b25f ("PCI: endpoint: functions: Add an EP function to test PCI")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>

PCI: endpoint: functions: Add an EP function to test PCI

Adds a new endpoint function driver (to program the virtual test device)
making use of the EP-core library.

[bhelgaas: fold in pci_epf_test_probe() -ENOMEM test from Wei Yongjun
<weiyongjun1@huawei.com>]
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>