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- ======================================================================
- 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. More description on the firmware is available in
- CPPI/QMSS Low Level Driver document (docs/CPPI_QMSS_LLD_SDS.pdf) at
- git://git.ti.com/keystone-rtos/qmss-lld.git
- k2_qmss_pdsp_acc48_k2_le_1_0_0_9.bin firmware supports upto 48 accumulator
- channels. This firmware is available under ti-keystone folder of
- firmware.git at
- git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
- To use copy the firmware image to lib/firmware folder of the initramfs or
- ubifs file system and provide a sym link to k2_qmss_pdsp_acc48_k2_le_1_0_0_9.bin
- in the file system and boot up the kernel. User would see
- "firmware file ks2_qmss_pdsp_acc48.bin downloaded for PDSP"
- in the boot up log if loading of firmware to PDSP is successful.
- Use of accumulated queues requires the firmware image to be present in the
- file system. The driver doesn't acc queues to the supported queue range if
- PDSP is not running in the SoC. The API call fails if there is a queue open
- request to an acc queue and PDSP is not running. So make sure to copy firmware
- to file system before using these queue types.
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