drivers/qcom: add RPMH communication support

Changes in v8:
- Bounds check for cmd_cache
- Describe interrupts to other DRVs in DT bindings
- Rebase on top of 4.17-rc3

Changes in v7:
- Rename 'm' and 'n' and use tcs_id and cmd_id instead
- Bug fix in find_match() and other review comments from Matthias
- Spinlock around get_rpmh_ctrlr()
- DT documentation example fixes
- Rebase on top of 4.16-rc2

Changes in v6:
- Remove tasklet in rpmh-rsc.c
- Remove rpmh_client and use struct device * instead
- Variable changes and bug fixes
- DT binding changes to describe all DRVs in the RSC
- Documentation and comment fixes

Changes in v5:
- Add Reviewed-by tags
- Rebase on top of 4.16

Changes in v4:
- Rename variables as suggested by Stephen and Evan
- Lot of minor syntax and style fixes
- Fix FTRACE compilation error
- Improve doc comments and DT description

Changes in v3:
- Address Steven's comments in FTRACE
- Fix DT documentation as suggested by Rob H
- Fix error handling in IRQ handler as suggested by Evan
- Remove locks in rpmh_flush()
- Improve comments

Changes in v2:
- Added sleep/wake, async and batch requests support
- Addressed Bjorn's comments
- Private FTRACE for drivers/soc/qcom as suggested by Steven
- Sparse checked on these patches
- Use SPDX license commenting sytle

This set of patches add the ability for platform drivers to make use of shared resources in newer Qualcomm SoCs like SDM845. Resources that are shared between multiple processors in a SoC are generally controlled by a dedicated remote processor. The remote processor (Resource Power Manager or RPM in previous QCOM SoCs) receives requests for resource state from other processors using the shared resource, aggregates the request and applies the result on the shared resource. SDM845 advances this concept and uses h/w (hardened I/P) blocks for aggregating requests and applying the result on the resource. The resources could be clocks, regulators or bandwidth requests for buses. This new architecture is called RPM-hardened or RPMH in short.

Since this communication mechanism is completely hardware driven without a processor intervention on the remote end, existing mechanisms like RPM-SMD are no longer useful. Also, there is no serialization of data or is data is written to a shared memory in this new format. The data used is different, unsigned 32 bits are used for representing an address, data and header. Each resource's property is a unique u32 address and have pre-defined set of property specific valid values. A request that comprises of <header, addr, data> is sent by writing to a set of registers from Linux and transmitted to the remote slave through an internal bus. The remote end aggregates this request along with requests from other processors for the <addr> and applies the result.

The hardware block that houses this functionality is called Resource State Coordinator or RSC. Inside the RSC are set of slots for sending RPMH requests called Trigger Commands Sets (TCS). The set of patches are for writing the requests into these TCSes and sending them to hardened IP blocks.

The driver design is split into two components. The RSC driver housed in rpmh-rsc.c and the set of library functions in rpmh.c that frame the request and transmit it using the controller. This first set of patches allow a simple synchronous request to be made by the platform drivers. Future patches will add more functionality that cater to complex drivers and use cases.

Please consider reviewing this patchset.

v1: https://www.spinics.net/lists/devicetree/msg210980.html
v2: https://lkml.org/lkml/2018/2/15/852
v3: https://lkml.org/lkml/2018/3/2/801
v4: https://lkml.org/lkml/2018/3/9/979
v5: https://lkml.org/lkml/2018/4/5/480
v6: https://lkml.org/lkml/2018/4/19/914
v7: https://lkml.org/lkml/2018/5/2/779

Lina Iyer (10):
drivers: qcom: rpmh-rsc: add RPMH controller for QCOM SoCs
dt-bindings: introduce RPMH RSC bindings for Qualcomm SoCs
drivers: qcom: rpmh-rsc: log RPMH requests in FTRACE
drivers: qcom: rpmh: add RPMH helper functions
drivers: qcom: rpmh-rsc: write sleep/wake requests to TCS
drivers: qcom: rpmh-rsc: allow invalidation of sleep/wake TCS
drivers: qcom: rpmh: cache sleep/wake state requests
drivers: qcom: rpmh: allow requests to be sent asynchronously
drivers: qcom: rpmh: add support for batch RPMH request
drivers: qcom: rpmh-rsc: allow active requests from wake TCS

 .../devicetree/bindings/soc/qcom/rpmh-rsc.txt | 137 ++++
 drivers/soc/qcom/Kconfig                      |  10 +
 drivers/soc/qcom/Makefile                     |   4 +
 drivers/soc/qcom/rpmh-internal.h              |  83 +++
 drivers/soc/qcom/rpmh-rsc.c                   | 683 ++++++++++++++++++
 drivers/soc/qcom/rpmh.c                       | 585 +++++++++++++++
 drivers/soc/qcom/trace-rpmh.h                 |  82 +++
 include/dt-bindings/soc/qcom,rpmh-rsc.h       |  14 +
 include/soc/qcom/rpmh.h                       |  51 ++
 include/soc/qcom/tcs.h                        |  56 ++
 10 files changed, 1705 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/qcom/rpmh-rsc.txt
 create mode 100644 drivers/soc/qcom/rpmh-internal.h
 create mode 100644 drivers/soc/qcom/rpmh-rsc.c
 create mode 100644 drivers/soc/qcom/rpmh.c
 create mode 100644 drivers/soc/qcom/trace-rpmh.h
 create mode 100644 include/dt-bindings/soc/qcom,rpmh-rsc.h
 create mode 100644 include/soc/qcom/rpmh.h
 create mode 100644 include/soc/qcom/tcs.h

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