Hi Felipe, Sorry for the ping, but was just wondering if you had any feedback on the latest txfifo resize patch series? I think I addressed the concerns you had about making sure we had enough FIFO size for a composition before allowing the configuration to bind with the check_config() API. It would ensure at least enough room for 1 max packet size for each EP in a configuration before allowing the bind to complete. That way we'd avoid being enumerated w/ the host, and having non-functioning endpoints. We've been testing these changes internally, and they are providing a pretty significant boost to our USB throughput numbers. Thanks Wesley Cheng On 5/19/2021 12:43 AM, Wesley Cheng wrote: > Changes in V8: > - Rebased to usb-testing > - Using devm_kzalloc for adding txfifo property in dwc3-qcom > - Removed DWC3 QCOM ACPI property for enabling the txfifo resize > > Changes in V7: > - Added a new property tx-fifo-max-num for limiting how much fifo space the > resizing logic can allocate for endpoints with large burst values. This > can differ across platforms, and tie in closely with overall system latency. > - Added recommended checks for DWC32. > - Added changes to set the tx-fifo-resize property from dwc3-qcom by default > instead of modifying the current DTSI files. > - Added comments on all APIs/variables introduced. > - Updated the DWC3 YAML to include a better description of the tx-fifo-resize > property and added an entry for tx-fifo-max-num. > > Changes in V6: > - Rebased patches to usb-testing. > - Renamed to PATCH series instead of RFC. > - Checking for fs_descriptors instead of ss_descriptors for determining the > endpoint count for a particular configuration. > - Re-ordered patch series to fix patch dependencies. > > Changes in V5: > - Added check_config() logic, which is used to communicate the number of EPs > used in a particular configuration. Based on this, the DWC3 gadget driver > has the ability to know the maximum number of eps utilized in all configs. > This helps reduce unnecessary allocation to unused eps, and will catch fifo > allocation issues at bind() time. > - Fixed variable declaration to single line per variable, and reverse xmas. > - Created a helper for fifo clearing, which is used by ep0.c > > Changes in V4: > - Removed struct dwc3* as an argument for dwc3_gadget_resize_tx_fifos() > - Removed WARN_ON(1) in case we run out of fifo space > > Changes in V3: > - Removed "Reviewed-by" tags > - Renamed series back to RFC > - Modified logic to ensure that fifo_size is reset if we pass the minimum > threshold. Tested with binding multiple FDs requesting 6 FIFOs. > > Changes in V2: > - Modified TXFIFO resizing logic to ensure that each EP is reserved a > FIFO. > - Removed dev_dbg() prints and fixed typos from patches > - Added some more description on the dt-bindings commit message > > Currently, there is no functionality to allow for resizing the TXFIFOs, and > relying on the HW default setting for the TXFIFO depth. In most cases, the > HW default is probably sufficient, but for USB compositions that contain > multiple functions that require EP bursting, the default settings > might not be enough. Also to note, the current SW will assign an EP to a > function driver w/o checking to see if the TXFIFO size for that particular > EP is large enough. (this is a problem if there are multiple HW defined > values for the TXFIFO size) > > It is mentioned in the SNPS databook that a minimum of TX FIFO depth = 3 > is required for an EP that supports bursting. Otherwise, there may be > frequent occurences of bursts ending. For high bandwidth functions, > such as data tethering (protocols that support data aggregation), mass > storage, and media transfer protocol (over FFS), the bMaxBurst value can be > large, and a bigger TXFIFO depth may prove to be beneficial in terms of USB > throughput. (which can be associated to system access latency, etc...) It > allows for a more consistent burst of traffic, w/o any interruptions, as > data is readily available in the FIFO. > > With testing done using the mass storage function driver, the results show > that with a larger TXFIFO depth, the bandwidth increased significantly. > > Test Parameters: > - Platform: Qualcomm SM8150 > - bMaxBurst = 6 > - USB req size = 256kB > - Num of USB reqs = 16 > - USB Speed = Super-Speed > - Function Driver: Mass Storage (w/ ramdisk) > - Test Application: CrystalDiskMark > > Results: > > TXFIFO Depth = 3 max packets > > Test Case | Data Size | AVG tput (in MB/s) > ------------------------------------------- > Sequential|1 GB x | > Read |9 loops | 193.60 > | | 195.86 > | | 184.77 > | | 193.60 > ------------------------------------------- > > TXFIFO Depth = 6 max packets > > Test Case | Data Size | AVG tput (in MB/s) > ------------------------------------------- > Sequential|1 GB x | > Read |9 loops | 287.35 > | | 304.94 > | | 289.64 > | | 293.61 > ------------------------------------------- > > Wesley Cheng (5): > usb: gadget: udc: core: Introduce check_config to verify USB > configuration > usb: gadget: configfs: Check USB configuration before adding > usb: dwc3: Resize TX FIFOs to meet EP bursting requirements > usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default > arm64: boot: dts: qcom: sm8150: Enable dynamic TX FIFO resize logic > > arch/arm64/boot/dts/qcom/sm8150.dtsi | 1 + > drivers/usb/dwc3/core.c | 9 ++ > drivers/usb/dwc3/core.h | 15 +++ > drivers/usb/dwc3/dwc3-qcom.c | 9 ++ > drivers/usb/dwc3/ep0.c | 2 + > drivers/usb/dwc3/gadget.c | 212 +++++++++++++++++++++++++++++++++++ > drivers/usb/gadget/configfs.c | 22 ++++ > drivers/usb/gadget/udc/core.c | 25 +++++ > include/linux/usb/gadget.h | 5 + > 9 files changed, 300 insertions(+) > -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
