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The switchtec kernel module implements this functionality.17
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Interface20
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=========21
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The primary means of communicating with the Switchtec management firmware is23
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through the Memory-mapped Remote Procedure Call (MRPC) interface.24
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Commands are submitted to the interface with a 4-byte command25
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identifier and up to 1KB of command specific data. The firmware will26
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respond with a 4 bytes return code and up to 1KB of command specific26
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respond with a 4-byte return code and up to 1KB of command-specific27
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data. The interface only processes a single command at a time.28
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Userspace Interface31
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===================32
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The MRPC interface will be exposed to userspace through a simple char34
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device: /dev/switchtec#, one for each management endpoint in the system.35
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The char device has the following semantics:37
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* A write must consist of at least 4 bytes and no more than 1028 bytes.39
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The first four bytes will be interpreted as the command to run and40
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the remainder will be used as the input data. A write will send the39
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The first 4 bytes will be interpreted as the Command ID and the40
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remainder will be used as the input data. A write will send the41
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command to the firmware to begin processing.42
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* Each write must be followed by exactly one read. Any double write will44
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produce an error and any read that doesn't follow a write will45
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produce an error.46
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* A read will block until the firmware completes the command and return48
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the four bytes of status plus up to 1024 bytes of output data. (The49
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length will be specified by the size parameter of the read call --50
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reading less than 4 bytes will produce an error.48
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the 4-byte Command Return Value plus up to 1024 bytes of output49
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data. (The length will be specified by the size parameter of the read50
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call -- reading less than 4 bytes will produce an error.)51
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* The poll call will also be supported for userspace applications that53
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need to do other things while waiting for the command to complete.54
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The following IOCTLs are also supported by the device:56
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* SWITCHTEC_IOCTL_FLASH_INFO - Retrieve firmware length and number58
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of partitions in the device.59
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* SWITCHTEC_IOCTL_FLASH_PART_INFO - Retrieve address and lengeth for76
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* SWITCHTEC_IOCTL_PFF_TO_PORT and SWITCHTEC_IOCTL_PORT_TO_PFF convert78
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between PCI Function Framework number (used by the event system)79
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and Switchtec Logic Port ID and Partition number (which is more80
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user friendly).81
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Non-Transparent Bridge (NTB) Driver84
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===================================85
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An NTB driver is provided for the switchtec hardware in switchtec_ntb.87
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Currently, it only supports switches configured with exactly 288
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partitions. It also requires the following configuration settings:86
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An NTB hardware driver is provided for the Switchtec hardware in87
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ntb_hw_switchtec. Currently, it only supports switches configured with88
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exactly 2 NT partitions and zero or more non-NT partitions. It also requires89
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the following configuration settings:89
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* Both partitions must be able to access each other's GAS spaces.91
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* Both NT partitions must be able to access each other's GAS spaces.91
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Thus, the bits in the GAS Access Vector under Management Settings92
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must be set to support this.94
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* Kernel configuration MUST include support for NTB (CONFIG_NTB needs95
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to be set)96
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NT EP BAR 2 will be dynamically configured as a Direct Window, and98
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the configuration file does not need to configure it explicitly.99
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Please refer to Documentation/ntb.txt in Linux source tree for an overall101
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understanding of the Linux NTB stack. ntb_hw_switchtec works as an NTB102
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Hardware Driver in this stack.