On Mon, Feb 28, 2022 at 06:13:17PM +0530, Manivannan Sadhasivam wrote: > Hello, > > This series adds initial support for the Qualcomm specific Modem Host Interface > (MHI) bus in endpoint devices like SDX55 modems. The MHI bus in endpoint devices > communicates with the MHI bus in host machines like x86 over any physical bus > like PCIe. The MHI host support is already in mainline [1] and been used by PCIe > based modems and WLAN devices running vendor code (downstream). > Series applied to mhi-next with Alex's Reviewed-by tag. Also incorporated few suggestions by Alex. Thanks, Mani > Overview > ======== > > This series aims at adding the MHI support in the endpoint devices with the goal > of getting data connectivity using the mainline kernel running on the modems. > Modems here refer to the combination of an APPS processor (Cortex A grade) and > a baseband processor (DSP). The MHI bus is located in the APPS processor and it > transfers data packets from the baseband processor to the host machine. > > The MHI Endpoint (MHI EP) stack proposed here is inspired by the downstream > code written by Qualcomm. But the complete stack is mostly re-written to adapt > to the "bus" framework and made it modular so that it can work with the upstream > subsystems like "PCI Endpoint". The code structure of the MHI endpoint stack > follows the MHI host stack to maintain uniformity. > > With this initial MHI EP stack (along with few other drivers), we can establish > the network interface between host and endpoint over the MHI software channels > (IP_SW0) and can do things like IP forwarding, SSH, etc... > > Stack Organization > ================== > > The MHI EP stack has the concept of controller and device drivers as like the > MHI host stack. The MHI EP controller driver can be a PCI Endpoint Function > driver and the MHI device driver can be a MHI EP Networking driver or QRTR > driver. The MHI EP controller driver is tied to the PCI Endpoint subsystem and > handles all bus related activities like mapping the host memory, raising IRQ, > passing link specific events etc... The MHI EP networking driver is tied to the > Networking stack and handles all networking related activities like > sending/receiving the SKBs from netdev, statistics collection etc... > > This series only contains the MHI EP code, whereas the PCIe EPF driver and MHI > EP Networking drivers are not yet submitted and can be found here [2]. Though > the MHI EP stack doesn't have the build time dependency, it cannot function > without them. > > Test setup > ========== > > This series has been tested on Telit FN980 TLB board powered by Qualcomm SDX55 > (a.k.a X55 modem) and Qualcomm SM8450 based dev board. > > For testing the stability and performance, networking tools such as iperf, ssh > and ping are used. > > Limitations > =========== > > We are not _yet_ there to get the data packets from the modem as that involves > the Qualcomm IP Accelerator (IPA) integration with MHI endpoint stack. But we > are planning to add support for it in the coming days. > > References > ========== > > MHI bus: https://www.kernel.org/doc/html/latest/mhi/mhi.html > Linaro connect presentation around this topic: https://connect.linaro.org/resources/lvc21f/lvc21f-222/ > > Thanks, > Mani > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/bus/mhi > [2] https://git.linaro.org/landing-teams/working/qualcomm/kernel.git/log/?h=tracking-qcomlt-sdx55-drivers > > Changes in v4: > > * Collected reviews from Hemant and Alex. > * Removed the A7 suffix from register names and functions. > * Added a couple of cleanup patches. > * Reworked the mhi_ep_queue_skb() API. > * Switched to separate workers for command and transfer rings. > * Used a common workqueue for state and ring management. > * Reworked the channel ring management. > * Other misc changes as per review from Alex. > > Changes in v3: > > * Splitted the patch 20/23 into two. > * Fixed the error handling in patch 21/23. > * Removed spurious change in patch 01/23. > * Added check for xfer callbacks in client driver probe. > > Changes in v2: > > v2 mostly addresses the issues seen while testing the stack on SM8450 that is a > SMP platform and also incorporates the review comments from Alex. > > Major changes are: > > * Added a cleanup patch for getting rid of SHIFT macros and used the bitfield > operations. > * Added the endianess patches that were submitted to MHI list and used the > endianess conversion in EP patches also. > * Added support for multiple event rings. > * Fixed the MSI generation based on the event ring index. > * Fixed the doorbell list handling by making use of list splice and not locking > the entire list manipulation. > * Added new APIs for wrapping the reading and writing to host memory (Dmitry). > * Optimized the read_channel and queue_skb function logics. > * Added Hemant's R-o-b tag. > > Manivannan Sadhasivam (25): > bus: mhi: Move host MHI code to "host" directory > bus: mhi: Use bitfield operations for register read and write > bus: mhi: Use bitfield operations for handling DWORDs of ring elements > bus: mhi: Cleanup the register definitions used in headers > bus: mhi: host: Rename "struct mhi_tre" to "struct mhi_ring_element" > bus: mhi: Move common MHI definitions out of host directory > bus: mhi: Make mhi_state_str[] array static inline and move to > common.h > bus: mhi: ep: Add support for registering MHI endpoint controllers > bus: mhi: ep: Add support for registering MHI endpoint client drivers > bus: mhi: ep: Add support for creating and destroying MHI EP devices > bus: mhi: ep: Add support for managing MMIO registers > bus: mhi: ep: Add support for ring management > bus: mhi: ep: Add support for sending events to the host > bus: mhi: ep: Add support for managing MHI state machine > bus: mhi: ep: Add support for processing MHI endpoint interrupts > bus: mhi: ep: Add support for powering up the MHI endpoint stack > bus: mhi: ep: Add support for powering down the MHI endpoint stack > bus: mhi: ep: Add support for handling MHI_RESET > bus: mhi: ep: Add support for handling SYS_ERR condition > bus: mhi: ep: Add support for processing command rings > bus: mhi: ep: Add support for reading from the host > bus: mhi: ep: Add support for processing channel rings > bus: mhi: ep: Add support for queueing SKBs to the host > bus: mhi: ep: Add support for suspending and resuming channels > bus: mhi: ep: Add uevent support for module autoloading > > Paul Davey (2): > bus: mhi: Fix pm_state conversion to string > bus: mhi: Fix MHI DMA structure endianness > > drivers/bus/Makefile | 2 +- > drivers/bus/mhi/Kconfig | 28 +- > drivers/bus/mhi/Makefile | 9 +- > drivers/bus/mhi/common.h | 326 +++++ > drivers/bus/mhi/core/internal.h | 722 ---------- > drivers/bus/mhi/ep/Kconfig | 10 + > drivers/bus/mhi/ep/Makefile | 2 + > drivers/bus/mhi/ep/internal.h | 222 +++ > drivers/bus/mhi/ep/main.c | 1623 ++++++++++++++++++++++ > drivers/bus/mhi/ep/mmio.c | 272 ++++ > drivers/bus/mhi/ep/ring.c | 197 +++ > drivers/bus/mhi/ep/sm.c | 148 ++ > drivers/bus/mhi/host/Kconfig | 31 + > drivers/bus/mhi/{core => host}/Makefile | 4 +- > drivers/bus/mhi/{core => host}/boot.c | 17 +- > drivers/bus/mhi/{core => host}/debugfs.c | 40 +- > drivers/bus/mhi/{core => host}/init.c | 131 +- > drivers/bus/mhi/host/internal.h | 382 +++++ > drivers/bus/mhi/{core => host}/main.c | 66 +- > drivers/bus/mhi/{ => host}/pci_generic.c | 0 > drivers/bus/mhi/{core => host}/pm.c | 36 +- > include/linux/mhi_ep.h | 284 ++++ > include/linux/mod_devicetable.h | 2 + > scripts/mod/file2alias.c | 10 + > 24 files changed, 3649 insertions(+), 915 deletions(-) > create mode 100644 drivers/bus/mhi/common.h > delete mode 100644 drivers/bus/mhi/core/internal.h > create mode 100644 drivers/bus/mhi/ep/Kconfig > create mode 100644 drivers/bus/mhi/ep/Makefile > create mode 100644 drivers/bus/mhi/ep/internal.h > create mode 100644 drivers/bus/mhi/ep/main.c > create mode 100644 drivers/bus/mhi/ep/mmio.c > create mode 100644 drivers/bus/mhi/ep/ring.c > create mode 100644 drivers/bus/mhi/ep/sm.c > create mode 100644 drivers/bus/mhi/host/Kconfig > rename drivers/bus/mhi/{core => host}/Makefile (54%) > rename drivers/bus/mhi/{core => host}/boot.c (96%) > rename drivers/bus/mhi/{core => host}/debugfs.c (90%) > rename drivers/bus/mhi/{core => host}/init.c (92%) > create mode 100644 drivers/bus/mhi/host/internal.h > rename drivers/bus/mhi/{core => host}/main.c (97%) > rename drivers/bus/mhi/{ => host}/pci_generic.c (100%) > rename drivers/bus/mhi/{core => host}/pm.c (97%) > create mode 100644 include/linux/mhi_ep.h > > -- > 2.25.1 >
