Introduce a new misc device driver for the Intel(r) Dynamic Load Balancer (Intel(r) DLB). The Intel DLB is a PCIe device that provides load-balanced, prioritized scheduling of core-to-core communication.
Intel DLB is an accelerator for the event-driven programming model of DPDK's Event Device Library[2]. The library is used in packet processing pipelines that arrange for multi-core scalability, dynamic load-balancing, and variety of packet distribution and synchronization schemes These distribution schemes include "parallel" (packets are load-balanced across multiple cores and processed in parallel), "ordered" (similar to "parallel" but packets are reordered into ingress order by the device), and "atomic" (packet flows are scheduled to a single core at a time such that locks are not required to access per-flow data, and dynamically migrated to ensure load-balance). This submission supports Intel DLB 2.0 only. The Intel DLB consists of queues and arbiters that connect producer cores and consumer cores. The device implements load-balanced queueing features including: - Lock-free multi-producer/multi-consumer operation. - Multiple priority levels for varying traffic types. - 'Direct' traffic (i.e. multi-producer/single-consumer) - Simple unordered load-balanced distribution. - Atomic lock free load balancing across multiple consumers. - Queue element reordering feature allowing ordered load-balanced distribution. The fundamental unit of communication through the device is a queue entry (QE), which consists of 8B of data and 8B of metadata (destination queue, priority, etc.). The data field can be any type that fits within 8B. A core's interface to the device, a "port," consists of a memory-mappable region through which the core enqueues a queue entry, and an in-memory queue (the "consumer queue") to which the device schedules QEs. Each QE is enqueued to a device-managed queue, and from there scheduled to a port. Software specifies the "linking" of queues and ports; i.e. which ports the device is allowed to schedule to for a given queue. The device uses a credit scheme to prevent overflow of the on-device queue storage. Applications can interface directly with the device by mapping the port's memory and MMIO regions into the application's address space for enqueue and dequeue operations, but call into the kernel driver for configuration operations. An application can also be polling- or interrupt-driven; Intel DLB supports both modes of operation. Device resources -- i.e. ports, queues, and credits -- are contained within a scheduling domain. Scheduling domains are isolated from one another; a port can only enqueue to and dequeue from queues within its scheduling domain. A scheduling domain's resources are configured through a scheduling domain file, which is acquired through an ioctl. Intel DLB supports SR-IOV and Scalable IOV, and allows for a flexible division of its resources among the PF and its virtual devices. The virtual devices are incapable of configuring the device directly; they use a hardware mailbox to proxy configuration requests to the PF driver. This driver supports both PF and virtual devices, as there is significant code re-use between the two, with device-specific behavior handled through a callback interface. Virtualization support will be added in a later patch set. The dlb driver uses ioctls as its primary interface (it makes use of sysfs as well, to a lesser extent). The dlb device file supports a different ioctl interface than the scheduling domain file; the dlb device file is used for device-wide operations (including scheduling domain creation), and the scheduling domain file supports operations on the scheduling domain's resources (primarily resource configuration). Scheduling domains are created dynamically (using a dlb device file ioctl) by user-space software, and the scheduling domain file is created from an anonymous file that is installed in the ioctl's calling process's file descriptor table. [1] https://builders.intel.com/docs/networkbuilders/SKU-343247-001US-queue-management-and-load-balancing-on-intel-architecture.pdf [2] https://doc.dpdk.org/guides/prog_guide/eventdev.html v9: - Addressed all of Greg's feecback on v8, including -- Remove function name (__func__) from dev_err() messages, that could spam log. -- Replace list and function pointer calls in dlb_ioctl() with switch-case and real function callsi for ioctl. -- Drop the compat_ptr_ioctl in dlb_ops (struct file_operations). -- Change ioctl magic number for DLB to unused 0x81 (from 'h'). -- Remove all placeholder/dummy functions in the patch set. -- Re-arrange the comments in dlb.h so that the order is consistent with that of data structures referred. -- Correct the comments on SPDX License and DLB versions in dlb.h. -- Replace BIT_SET() and BITS_CLR() marcos with direct coding. -- Remove NULL pointer checking (f->private_data) in dlb_ioctl(). -- Use whole line whenever possible and not wrapping lines unnecessarily. -- Remove __attribute__((unused)). -- Merge dlb_ioctl.h and dlb_file.h into dlb_main.h v8: - Add a functional block diagram in dlb.rst - Modify change logs to reflect the links between patches and DPDK eventdev library. - Add a check of power-of-2 for CQ depth. - Move call to INIT_WORK() to dlb_open(). - Clean dlb workqueue by calling flush_scheduled_work(). - Add unmap_mapping_range() in dlb_port_close(). v7 (Intel internal version): - Address all of Dan's feedback, including -- Drop DLB 2.0 throughout the patch set, use DLB only. -- Fix license and copyright statements -- Use pcim_enable_device() and pcim_iomap_regions(), instead of unmanaged version. -- Move cdev_add() to dlb_init() and add all devices at once. -- Fix Makefile, using "+=" style. -- Remove FLR description and mention movdir64/enqcmd usage in doc. -- Make the permission for the domain same as that for device for ioctl access. -- Use idr instead of ida. -- Add a lock in dlb_close() to prevent driver unbinding while ioctl coomands are in progress. -- Remove wrappers that are used for code sharing between kernel driver and DPDK. - Address Pierre-Louis' feedback, including -- Clean the warinings from checkpatch -- Fix the warnings from "make W=1" v6 (Intel internal version): - Change the module name to dlb(from dlb2), which currently supports Intel DLB 2.0 only. - Address all of Pierre-Louis' feedback on v5, including -- Consolidate the two near-identical for loops in dlb2_release_domain_memory(). -- Remove an unnecessary "port = NULL" initialization -- Consistently use curly braces on the *_LIST_FOR macros when the for-loop contents spans multiple lines. -- Add a comment to the definition of DLB2FS_MAGIC -- Remove always true if statemnets -- Move the get_cos_bw mutex unlock call earlier to shorten the critical section. - Address all of Dan's feedbacks, including -- Replace the unions for register bits access with bitmask and shifts -- Centralize the "to/from" user memory copies for ioctl functions. -- Review ioctl design against Documentation/process/botching-up-ioctls.rst -- Remove wraper functions for memory barriers. -- Use ilog() to simplify a switch code block. -- Add base-commit to cover letter. v5 (Intel internal version): - Reduce the scope of the initial patch set (drop the last 8 patches) - Further decompose some of the remaining patches into multiple patches. - Address all of Pierre-Louis' feedback, including: -- Move kerneldoc to *.c files -- Fix SPDX comment style -- Add BAR macros -- Improve/clarify struct dlb2_dev and struct device variable naming -- Add const where missing -- Clarify existing comments and add new ones in various places -- Remove unnecessary memsets and zero-initialization -- Remove PM abstraction, fix missing pm_runtime_allow(), and don't update PM refcnt when port files are opened and closed. -- Convert certain ternary operations into if-statements -- Out-line the CQ depth valid check -- De-duplicate the logic in dlb2_release_device_memory() -- Limit use of devm functions to allocating/freeing struct dlb2 - Address Ira's comments on dlb2.rst and correct commit messages that don't use the imperative voice. v4: - Move PCI device ID definitions into dlb2_hw_types.h, drop the VF definition - Remove dlb2_dev_list - Remove open/close functions and fops structure (unused) - Remove "(char *)" cast from PCI driver name - Unwind init failures properly - Remove ID alloc helper functions and call IDA interfaces directly instead v3: - Remove DLB2_PCI_REG_READ/WRITE macros v2: - Change driver license to GPLv2 only - Expand Kconfig help text and remove unnecessary (R)s - Remove unnecessary prints - Add a new entry in ioctl-number.rst - Convert the ioctl handler into a switch statement - Correct some instances of IOWR that should have been IOR - Align macro blocks - Don't break ioctl ABI when introducing new commands - Remove indirect pointers from ioctl data structures - Remove the get-sched-domain-fd ioctl command Mike Ximing Chen (20): dlb: add skeleton for DLB driver dlb: initialize device dlb: add resource and device initialization dlb: add device ioctl layer and first three ioctls dlb: add scheduling domain configuration dlb: add domain software reset dlb: add low-level register reset operations dlb: add runtime power-management support dlb: add queue create, reset, get-depth ioctls dlb: add register operations for queue management dlb: add ioctl to configure ports and query poll mode dlb: add register operations for port management dlb: add port mmap support dlb: add start domain ioctl dlb: add queue map, unmap, and pending unmap operations dlb: add port map/unmap state machine dlb: add static queue map register operations dlb: add dynamic queue map register operations dlb: add queue unmap register operations dlb: queue map/unmap workqueue Documentation/misc-devices/dlb.rst | 259 + Documentation/misc-devices/index.rst | 1 + .../userspace-api/ioctl/ioctl-number.rst | 1 + MAINTAINERS | 8 + drivers/misc/Kconfig | 1 + drivers/misc/Makefile | 1 + drivers/misc/dlb/Kconfig | 18 + drivers/misc/dlb/Makefile | 11 + drivers/misc/dlb/dlb_bitmap.h | 210 + drivers/misc/dlb/dlb_file.c | 149 + drivers/misc/dlb/dlb_hw_types.h | 311 + drivers/misc/dlb/dlb_ioctl.c | 498 ++ drivers/misc/dlb/dlb_main.c | 614 ++ drivers/misc/dlb/dlb_main.h | 178 + drivers/misc/dlb/dlb_pf_ops.c | 277 + drivers/misc/dlb/dlb_regs.h | 3640 +++++++++++ drivers/misc/dlb/dlb_resource.c | 5469 +++++++++++++++++ drivers/misc/dlb/dlb_resource.h | 94 + include/uapi/linux/dlb.h | 602 ++ 19 files changed, 12342 insertions(+) create mode 100644 Documentation/misc-devices/dlb.rst create mode 100644 drivers/misc/dlb/Kconfig create mode 100644 drivers/misc/dlb/Makefile create mode 100644 drivers/misc/dlb/dlb_bitmap.h create mode 100644 drivers/misc/dlb/dlb_file.c create mode 100644 drivers/misc/dlb/dlb_hw_types.h create mode 100644 drivers/misc/dlb/dlb_ioctl.c create mode 100644 drivers/misc/dlb/dlb_main.c create mode 100644 drivers/misc/dlb/dlb_main.h create mode 100644 drivers/misc/dlb/dlb_pf_ops.c create mode 100644 drivers/misc/dlb/dlb_regs.h create mode 100644 drivers/misc/dlb/dlb_resource.c create mode 100644 drivers/misc/dlb/dlb_resource.h create mode 100644 include/uapi/linux/dlb.h base-commit: e71ba9452f0b5b2e8dc8aa5445198cd9214a6a62 -- 2.17.1
