NTB: Introduce MSI library

The NTB MSI library allows passing MSI interrupts across a memory
window. This offers similar functionality to doorbells or messages
except will often have much better lat

NTB: Introduce MSI library

The NTB MSI library allows passing MSI interrupts across a memory
window. This offers similar functionality to doorbells or messages
except will often have much better latency and the client can
potentially use significantly more remote interrupts than typical hardware
provides for doorbells. (Which can be important in high-multiport
setups.)

The library utilizes one memory window per peer and uses the highest
index memory windows. Before any ntb_msi function may be used, the user
must call ntb_msi_init(). It may then setup and tear down the memory
windows when the link state changes using ntb_msi_setup_mws() and
ntb_msi_clear_mws().

The peer which receives the interrupt must call ntb_msim_request_irq()
to assign the interrupt handler (this function is functionally
similar to devm_request_irq()) and the returned descriptor must be
transferred to the peer which can use it to trigger the interrupt.
The triggering peer, once having received the descriptor, can
trigger the interrupt by calling ntb_msi_peer_trigger().

Signed-off-by: Logan Gunthorpe <[email protected]>
Cc: Dave Jiang <[email protected]>
Cc: Allen Hubbe <[email protected]>
Signed-off-by: Jon Mason <[email protected]>

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treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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NTB: Add ping pong test client

This is a simple ping pong driver that exercises the scratch pads and
doorbells of the ntb hardware. This driver may be used to test that
your ntb hardware and driver

NTB: Add ping pong test client

This is a simple ping pong driver that exercises the scratch pads and
doorbells of the ntb hardware. This driver may be used to test that
your ntb hardware and drivers are functioning at a basic level.

Signed-off-by: Allen Hubbe <[email protected]>
Signed-off-by: Jon Mason <[email protected]>

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NTB: Split ntb_hw_intel and ntb_transport drivers

Change ntb_hw_intel to use the new NTB hardware abstraction layer.

Split ntb_transport into its own driver. Change it to use the new NTB
hardware

NTB: Split ntb_hw_intel and ntb_transport drivers

Change ntb_hw_intel to use the new NTB hardware abstraction layer.

Split ntb_transport into its own driver. Change it to use the new NTB
hardware abstraction layer.

Signed-off-by: Allen Hubbe <[email protected]>
Signed-off-by: Jon Mason <[email protected]>

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NTB: Enable 32bit Support

Correct the issues on NTB that prevented it from working on x86_32 and
modify the Kconfig to allow it to be permitted to be used in that
environment as well.

Signed-off-by

NTB: Enable 32bit Support

Correct the issues on NTB that prevented it from working on x86_32 and
modify the Kconfig to allow it to be permitted to be used in that
environment as well.

Signed-off-by: Jon Mason <[email protected]>

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NTB: disable x86_32 support

Atomic readq and writeq do not exist by default on some 32bit
architectures, thus causing compile errors due to non-existent symbols.
Since NTB has not been tested 32bit,

NTB: disable x86_32 support

Atomic readq and writeq do not exist by default on some 32bit
architectures, thus causing compile errors due to non-existent symbols.
Since NTB has not been tested 32bit, disable x86_32 support until such
time as this and any other issues can be properly discovered.

Signed-off-by: Jon Mason <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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PCI-Express Non-Transparent Bridge Support

A PCI-Express non-transparent bridge (NTB) is a point-to-point PCIe bus
connecting 2 systems, providing electrical isolation between the two subsystems.
A

PCI-Express Non-Transparent Bridge Support

A PCI-Express non-transparent bridge (NTB) is a point-to-point PCIe bus
connecting 2 systems, providing electrical isolation between the two subsystems.
A non-transparent bridge is functionally similar to a transparent bridge except
that both sides of the bridge have their own independent address domains. The
host on one side of the bridge will not have the visibility of the complete
memory or I/O space on the other side of the bridge. To communicate across the
non-transparent bridge, each NTB endpoint has one (or more) apertures exposed to
the local system. Writes to these apertures are mirrored to memory on the
remote system. Communications can also occur through the use of doorbell
registers that initiate interrupts to the alternate domain, and scratch-pad
registers accessible from both sides.

The NTB device driver is needed to configure these memory windows, doorbell, and
scratch-pad registers as well as use them in such a way as they can be turned
into a viable communication channel to the remote system. ntb_hw.[ch]
determines the usage model (NTB to NTB or NTB to Root Port) and abstracts away
the underlying hardware to provide access and a common interface to the doorbell
registers, scratch pads, and memory windows. These hardware interfaces are
exported so that other, non-mainlined kernel drivers can access these.
ntb_transport.[ch] also uses the exported interfaces in ntb_hw.[ch] to setup a
communication channel(s) and provide a reliable way of transferring data from
one side to the other, which it then exports so that "client" drivers can access
them. These client drivers are used to provide a standard kernel interface
(i.e., Ethernet device) to NTB, such that Linux can transfer data from one
system to the other in a standard way.

Signed-off-by: Jon Mason <[email protected]>
Reviewed-by: Nicholas Bellinger <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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