Hi Randy, On 08/02/2018 03:05 AM, Randy Dunlap wrote: > On 07/31/2018 09:13 AM, Georgi Djakov wrote: >> This patch introduces a new API to get requirements and configure the >> interconnect buses across the entire chipset to fit with the current >> demand. >> >> The API is using a consumer/provider-based model, where the providers are >> the interconnect buses and the consumers could be various drivers. >> The consumers request interconnect resources (path) between endpoints and >> set the desired constraints on this data flow path. The providers receive >> requests from consumers and aggregate these requests for all master-slave >> pairs on that path. Then the providers configure each participating in the >> topology node according to the requested data flow path, physical links and >> constraints. The topology could be complicated and multi-tiered and is SoC >> specific. >> >> Signed-off-by: Georgi Djakov <georgi.djakov@xxxxxxxxxx> >> --- >> Documentation/interconnect/interconnect.rst | 96 ++++ >> drivers/Kconfig | 2 + >> drivers/Makefile | 1 + >> drivers/interconnect/Kconfig | 10 + >> drivers/interconnect/Makefile | 2 + >> drivers/interconnect/core.c | 569 ++++++++++++++++++++ >> include/linux/interconnect-provider.h | 125 +++++ >> include/linux/interconnect.h | 42 ++ >> 8 files changed, 847 insertions(+) >> create mode 100644 Documentation/interconnect/interconnect.rst >> create mode 100644 drivers/interconnect/Kconfig >> create mode 100644 drivers/interconnect/Makefile >> create mode 100644 drivers/interconnect/core.c >> create mode 100644 include/linux/interconnect-provider.h >> create mode 100644 include/linux/interconnect.h >> >> diff --git a/Documentation/interconnect/interconnect.rst b/Documentation/interconnect/interconnect.rst >> new file mode 100644 >> index 000000000000..e628881ee218 >> --- /dev/null >> +++ b/Documentation/interconnect/interconnect.rst >> @@ -0,0 +1,96 @@ >> +.. SPDX-License-Identifier: GPL-2.0 >> + >> +===================================== >> +GENERIC SYSTEM INTERCONNECT SUBSYSTEM >> +===================================== >> + >> +Introduction >> +------------ >> + >> +This framework is designed to provide a standard kernel interface to control >> +the settings of the interconnects on a SoC. These settings can be throughput, > > I would say: on an SoC. > > Do you pronounce that as "sock" or the letters S.O.C.? Ah right indeed, this should be based on the phonetics and not the writing. >> +latency and priority between multiple interconnected devices or functional >> +blocks. This can be controlled dynamically in order to save power or provide >> +maximum performance. >> + >> +The interconnect bus is a hardware with configurable parameters, which can be > > bus is hardware Ok. >> +set on a data path according to the requests received from various drivers. >> +An example of interconnect buses are the interconnects between various >> +components or functional blocks in chipsets. There can be multiple interconnects >> +on a SoC that can be multi-tiered. > > an SoC > >> + >> +Below is a simplified diagram of a real-world SoC interconnect bus topology. >> + >> +:: >> + >> + +----------------+ +----------------+ >> + | HW Accelerator |--->| M NoC |<---------------+ >> + +----------------+ +----------------+ | >> + | | +------------+ >> + +-----+ +-------------+ V +------+ | | >> + | DDR | | +--------+ | PCIe | | | >> + +-----+ | | Slaves | +------+ | | >> + ^ ^ | +--------+ | | C NoC | >> + | | V V | | >> + +------------------+ +------------------------+ | | +-----+ >> + | |-->| |-->| |-->| CPU | >> + | |-->| |<--| | +-----+ >> + | Mem NoC | | S NoC | +------------+ >> + | |<--| |---------+ | >> + | |<--| |<------+ | | +--------+ >> + +------------------+ +------------------------+ | | +-->| Slaves | >> + ^ ^ ^ ^ ^ | | +--------+ >> + | | | | | | V >> + +------+ | +-----+ +-----+ +---------+ +----------------+ +--------+ >> + | CPUs | | | GPU | | DSP | | Masters |-->| P NoC |-->| Slaves | >> + +------+ | +-----+ +-----+ +---------+ +----------------+ +--------+ >> + | >> + +-------+ >> + | Modem | >> + +-------+ >> + >> +Terminology >> +----------- >> + >> +Interconnect provider is the software definition of the interconnect hardware. >> +The interconnect providers on the above diagram are M NoC, S NoC, C NoC, P NoC >> +and Mem NoC. >> + >> +Interconnect node is the software definition of the interconnect hardware >> +port. Each interconnect provider consists of multiple interconnect nodes, >> +which are connected to other SoC components including other interconnect >> +providers. The point on the diagram where the CPUs connect to the memory is >> +called an interconnect node, which belongs to the Mem NoC interconnect provider. >> + >> +Interconnect endpoints are the first or the last element of the path. Every >> +endpoint is a node, but not every node is an endpoint. >> + >> +Interconnect path is everything between two endpoints including all the nodes >> +that have to be traversed to reach from a source to destination node. It may >> +include multiple master-slave pairs across several interconnect providers. >> + >> +Interconnect consumers are the entities which make use of the data paths exposed >> +by the providers. The consumers send requests to providers requesting various >> +throughput, latency and priority. Usually the consumers are device drivers, that >> +send request based on their needs. An example for a consumer is a video decoder >> +that supports various formats and image sizes. >> + >> +Interconnect providers >> +---------------------- >> + >> +Interconnect provider is an entity that implements methods to initialize and >> +configure a interconnect bus hardware. The interconnect provider drivers should > > configure interconnect bus hardware. > (i.e., drop the "a") Ok. >> +be registered with the interconnect provider core. >> + >> +The interconnect framework provider API functions are documented in >> +.. kernel-doc:: include/linux/interconnect-provider.h > > What do you want that to do? and does that happen? > > The .. kernel-doc:: line won't be printed. It will just be expanded to the > contents of that header file, so the preceding sentence fragment will look/sound > odd. Thanks for catching this, I understood it incorrectly. Will improve it. BR, Georgi >> + >> +Interconnect consumers >> +---------------------- >> + >> +Interconnect consumers are the clients which use the interconnect APIs to >> +get paths between endpoints and set their bandwidth/latency/QoS requirements >> +for these interconnect paths. >> + >> +The interconnect framework consumer API functions are documented in >> +.. kernel-doc:: include/linux/interconnect.h > > same as above. > > -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
