On Wed, 2020-01-29 at 09:57 +0530, Sandeep Singh wrote: > From: Sandeep Singh <sandeep.singh@xxxxxxx> > > Add Maintainer list for AMD SFH SFH (SENSOR FUSION HUB) This way it will be clear what is SFH. > Solution and work flow > document. > > Signed-off-by: Nehal Shah <Nehal-bakulchandra.Shah@xxxxxxx> > Signed-off-by: Sandeep Singh <sandeep.singh@xxxxxxx> > --- > Documentation/hid/amd-sfh-hid.rst | 159 > ++++++++++++++++++++++++++++++++++++++ > MAINTAINERS | 8 ++ > 2 files changed, 167 insertions(+) > create mode 100644 Documentation/hid/amd-sfh-hid.rst > > diff --git a/Documentation/hid/amd-sfh-hid.rst > b/Documentation/hid/amd-sfh-hid.rst > new file mode 100644 > index 0000000..1183350 > --- /dev/null > +++ b/Documentation/hid/amd-sfh-hid.rst > @@ -0,0 +1,159 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +AMD Sensor Fusion Hub:- > +====================== > +AMD sensor fushion Hub is part of a SOC starting from ryzon based > platforms. > +The solution is working well on windows OS in several > +OEM products. AMD SFH uses HID over PCIe bus. In terms of > architecture > +it is much more resmebles like ISH .However the major diffrence is > all > +The hid reports are generated as part of kernel driver. > + > +Block Diagram:- > +============= > + ------------------------------- > + | HID User Space Applications | > + ------------------------------- > +--------------------------------------------- > + --------------------------------- > + | HID Core | > + --------------------------------- > + > + --------------------------------- > + | AMD HID Transport Driver | > + --------------------------------- > + > + -------------------------------- > + | AMD HID Client Driver | > + | with HID Report Generator| > + -------------------------------- > + > + -------------------------------- > + | AMD MP2 PCIe Driver | > + -------------------------------- > +--------------------------------------------- > + ------------------------------- > + | SFH MP2 Processor | > + -------------------------------- > + > + > +AMD HID Transport Layer :- > +*************************** > +AMD SFH transport is also implemented as a bus. Each client > application > +executing in the AMD MP2 is registered as a device on this bus. > +The driver, which binds each device (AMD SFH HID driver) identifies > +the device type and registers with the hid core. Transport drivers > +attach a constant "struct hid_ll_driver" object with each device. > +Once a device is registered with HID core, the callbacks provided > via > +this struct are used by HID core to communicate with the device. > +AMD HID Transport driver implements the synchronous calls. > + > +AMD HID Client Driver:- > +********************** > +This driver is responsible to implement HID request and descriptors. > +As firmware is OS agnostic, HID client driver fills the HID request > +structure and descriptors. HID client driver is in complex in nature > +as it is interface between MP2 PCIe driver and HID. HID client > driver > +initialized the MP2 PCIe driver and holds the instance of MP2 > driver. > +It identified the number of sensors connected using MP2- PCIe driver > and > +based on that allocate the DRAM address for each and every sensor > and > +pass it to MP2-PCIe driver. > +On enumeration of each sensor, client driver fills out the HID > Descriptor > +structure and HID input report structure. HID Feature report > structure can > +be optional. The report descriptor structure varies sensor to > sensor. > +Now on enumeration client driver does two major things > +1. Register the HID sensor client to virtual bus (Platform driver) > and bind it. > +2. Probes the AMD HID transport driver. Which in turns register > device to the core. > + > +AMD MP2 PCIe Driver:- > +******************** > +MP2 PCIe driver is responsible for making all transaction with the > firmware over > +PCIe.The connection establishment between firmware and MP2 PCIe > driver happens here. > + > +The communication between X86 and MP2 is spilt into three parts. > +1. Command Transfer => C2P Mailbox Register are used > +2. Data Transfer => DRAM > + > +Commands are sent to MP2 using C2P Mail Box registers. These > C2P registers > +are mapped in PCIe address space.Writing into C2P Message register > generate > +interrupt to MP2. The client driver allocates the physical memory > and send > +the same to MP2 for data transfer. MP2 firmware uses DRAM interface > registers > +to indirectly access DRAM memory. For Firmware always write minimum > 32 bytes > +into DRAM.So it is expected that driver shall allocate minimum 32 > bytes DRAM space. > + > +Enumeration and Probing flow:- > +***************************** > + HID AMD AMD AMD > -PCIe MP2 > + Core Transport Client > Driver Driver FW > + | | | | > | > + | | on Boot Driver Loaded | > | > + | | | | > | > + | | |----MP2-PCIe Int---------> > | | > + | | | | > | > + | | |---Get Number of sensors-> > | | > + | | | Read > P2C | > + | | | Register > | > + | | | | > | > + | | | Loop(for No of > Sensors) | | > + | | |-------------------- > --| | | > + | | | Create HID > Descriptor| | | > + | | | Create Input report > | | | > + | | | Descriptor > Map | | | > + | | | the MP2 FW Index to > | | | > + | | | HID > Index | | | > + | | | Allocate the > DRAM | Enable | > + | | | address | Sensors > | > + | | |-------------------- > --| | | > + | | HID > transport| | Enable | > + | |<--Probe------| |---Sensor > CMD--> | > + | | Create the | | > | > + | | HID > device | | | > + | | (MFD) | | > | > + | | by Populating| | > | > + | | the > HID | | | > + | | ll_driver | | > | > + | HID | | | > | > + | add | | | > | > + |Device | | | > | > + |<------------- | | | > | > + > + > +Data Flow from Application to the AMD SFH Driver:- > +************************************************* > + > + | | | | > | > +Get | | | | > | > +Input | | | | > | > +Report | | | > | | > +---> | | | > | | > + |HID_req | | | > | > + |get_report | | | > | > + |------------- > >| | | | > + | | > HID_get_input| | | > + | | report | | > | > + | |------------->|---------------------- > --| | | > + | | | Read the DRAM data > for| | | > + | | | requsted sensor > and | | | > + | | | create the HID > input | | | > + | | | report | | > | > + | | |---------------------- > --| | | > + | |Data received > | | | > + | | in HID > report| | | > + To |<-------------|<------------- > | | | > +Applications | | | > | > +<------- > | | | | > | > + > + > +Data Flow from AMD SFH Driver to Application:- > +********************************************** > + | | | > | | > + | | |---------------------- > --| | | > + | | |Periodically > Read | | | > + | | |the data for > all | | | > + | | |enumerated > sensors | | | > + | | |from the dram and > create| | | > + | | | HID Input > reports | | | > + | | |---------------------- > --| | | > + | |HID > Input | | | > + | |Input > report | | | > + <----submit to Application----- > | | | > + | | | | > | > diff --git a/MAINTAINERS b/MAINTAINERS > index 56765f5..7cfeb5a 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -884,6 +884,14 @@ S: Supported > F: drivers/net/ethernet/amd/xgbe/ > F: arch/arm64/boot/dts/amd/amd-seattle-xgbe*.dtsi > > +AMD SENSOR FUSION HUB DRIVER > +M: Nehal Shah <nehal-bakulchandra.shah@xxxxxxx> > +M: Sandeep Singh <sandeep.singh@xxxxxxx> > +L: linux-input@xxxxxxxxxxxxxxx > +S: Maintained > +F: Documentation/hid/amd-sfh* > +F: drivers/hid/amd-sfh-hid/ > + > ANALOG DEVICES INC AD5686 DRIVER > M: Stefan Popa <stefan.popa@xxxxxxxxxx> > L: linux-pm@xxxxxxxxxxxxxxx
