Texas Instruments Keystone Navigator Queue Management SubSystem driver — The Linux Kernel 5.18.5-gnu-1 documentation

# Texas Instruments Keystone Navigator Queue Management SubSystem driver

Driver source code path

  drivers/soc/ti/knav_qmss.c drivers/soc/ti/knav_qmss_acc.c

The QMSS (Queue Manager Sub System) found on Keystone SOCs is one of the main hardware sub system which forms the backbone of the Keystone multi-core Navigator. QMSS consist of queue managers, packed-data structure processors(PDSP), linking RAM, descriptor pools and infrastructure Packet DMA. The Queue Manager is a hardware module that is responsible for accelerating management of the packet queues. Packets are queued/de-queued by writing or reading descriptor address to a particular memory mapped location. The PDSPs perform QMSS related functions like accumulation, QoS, or event management. Linking RAM registers are used to link the descriptors which are stored in descriptor RAM. Descriptor RAM is configurable as internal or external memory. The QMSS driver manages the PDSP setups, linking RAM regions, queue pool management (allocation, push, pop and notify) and descriptor pool management.

knav qmss driver provides a set of APIs to drivers to open/close qmss queues, allocate descriptor pools, map the descriptors, push/pop to queues etc. For details of the available APIs, please refers to include/linux/soc/ti/knav_qmss.h

DT documentation is available at Documentation/devicetree/bindings/soc/ti/keystone-navigator-qmss.txt

## Accumulator QMSS queues using PDSP firmware

The QMSS PDSP firmware support accumulator channel that can monitor a single queue or multiple contiguous queues. drivers/soc/ti/knav_qmss_acc.c is the driver that interface with the accumulator PDSP. This configures accumulator channels defined in DTS (example in DT documentation) to monitor 1 or 32 queues per channel. /(DEBLOBBED)/