1======================================================================
2Texas Instruments Keystone Navigator Queue Management SubSystem driver
3======================================================================
4
5Driver source code path
6  drivers/soc/ti/knav_qmss.c
7  drivers/soc/ti/knav_qmss_acc.c
8
9The QMSS (Queue Manager Sub System) found on Keystone SOCs is one of
10the main hardware sub system which forms the backbone of the Keystone
11multi-core Navigator. QMSS consist of queue managers, packed-data structure
12processors(PDSP), linking RAM, descriptor pools and infrastructure
13Packet DMA.
14The Queue Manager is a hardware module that is responsible for accelerating
15management of the packet queues. Packets are queued/de-queued by writing or
16reading descriptor address to a particular memory mapped location. The PDSPs
17perform QMSS related functions like accumulation, QoS, or event management.
18Linking RAM registers are used to link the descriptors which are stored in
19descriptor RAM. Descriptor RAM is configurable as internal or external memory.
20The QMSS driver manages the PDSP setups, linking RAM regions,
21queue pool management (allocation, push, pop and notify) and descriptor
22pool management.
23
24knav qmss driver provides a set of APIs to drivers to open/close qmss queues,
25allocate descriptor pools, map the descriptors, push/pop to queues etc. For
26details of the available APIs, please refers to include/linux/soc/ti/knav_qmss.h
27
28DT documentation is available at
29Documentation/devicetree/bindings/soc/ti/keystone-navigator-qmss.txt
30
31Accumulator QMSS queues using PDSP firmware
32============================================
33The QMSS PDSP firmware support accumulator channel that can monitor a single
34queue or multiple contiguous queues. drivers/soc/ti/knav_qmss_acc.c is the
35driver that interface with the accumulator PDSP. This configures
36accumulator channels defined in DTS (example in DT documentation) to monitor
371 or 32 queues per channel. More description on the firmware is available in
38CPPI/QMSS Low Level Driver document (docs/CPPI_QMSS_LLD_SDS.pdf) at
39
40	git://git.ti.com/keystone-rtos/qmss-lld.git
41
42k2_qmss_pdsp_acc48_k2_le_1_0_0_9.bin firmware supports upto 48 accumulator
43channels. This firmware is available under ti-keystone folder of
44firmware.git at
45
46   git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git
47
48To use copy the firmware image to lib/firmware folder of the initramfs or
49ubifs file system and provide a sym link to k2_qmss_pdsp_acc48_k2_le_1_0_0_9.bin
50in the file system and boot up the kernel. User would see
51
52 "firmware file ks2_qmss_pdsp_acc48.bin downloaded for PDSP"
53
54in the boot up log if loading of firmware to PDSP is successful.
55
56Use of accumulated queues requires the firmware image to be present in the
57file system. The driver doesn't acc queues to the supported queue range if
58PDSP is not running in the SoC. The API call fails if there is a queue open
59request to an acc queue and PDSP is not running. So make sure to copy firmware
60to file system before using these queue types.
61