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Abstract the NTB device behind a programming interface, so that it can support different hardware and client drivers. Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
33 lines
1.5 KiB
Plaintext
33 lines
1.5 KiB
Plaintext
# NTB Drivers
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NTB (Non-Transparent Bridge) is a type of PCI-Express bridge chip that connects
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the separate memory systems of two computers to the same PCI-Express fabric.
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Existing NTB hardware supports a common feature set, including scratchpad
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registers, doorbell registers, and memory translation windows. Scratchpad
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registers are read-and-writable registers that are accessible from either side
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of the device, so that peers can exchange a small amount of information at a
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fixed address. Doorbell registers provide a way for peers to send interrupt
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events. Memory windows allow translated read and write access to the peer
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memory.
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## NTB Core Driver (ntb)
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The NTB core driver defines an api wrapping the common feature set, and allows
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clients interested in NTB features to discover NTB the devices supported by
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hardware drivers. The term "client" is used here to mean an upper layer
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component making use of the NTB api. The term "driver," or "hardware driver,"
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is used here to mean a driver for a specific vendor and model of NTB hardware.
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## NTB Client Drivers
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NTB client drivers should register with the NTB core driver. After
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registering, the client probe and remove functions will be called appropriately
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as ntb hardware, or hardware drivers, are inserted and removed. The
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registration uses the Linux Device framework, so it should feel familiar to
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anyone who has written a pci driver.
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## NTB Hardware Drivers
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NTB hardware drivers should register devices with the NTB core driver. After
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registering, clients probe and remove functions will be called.
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