scsi: mpi3mr: Create operational request and reply queue pair
Create operational request and reply queue pair. The MPI3 transport interface consists of an Administrative Request Queue, an Administrative Reply Queue, and Operational Messaging Queues. The Operational Messaging Queues are the primary communication mechanism between the host and the I/O Controller (IOC). Request messages, allocated in host memory, identify I/O operations to be performed by the IOC. These operations are queued on an Operational Request Queue by the host driver. Reply descriptors track I/O operations as they complete. The IOC queues these completions in an Operational Reply Queue. To fulfil large contiguous memory requirement, driver creates multiple segments and provide the list of segments. Each segment size should be 4K which is a hardware requirement. An element array is contiguous or segmented. A contiguous element array is located in contiguous physical memory. A contiguous element array must be aligned on an element size boundary. An element's physical address within the array may be directly calculated from the base address, the Producer/Consumer index, and the element size. Expected phased identifier bit is used to find out valid entry on reply queue. Driver sets <ephase> bit and IOC inverts the value of this bit on each pass. Link: https://lore.kernel.org/r/20210520152545.2710479-4-kashyap.desai@broadcom.com Cc: sathya.prakash@broadcom.com Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Tomas Henzl <thenzl@redhat.com> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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