From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ... --- .../device_drivers/ethernet/toshiba/spider_net.rst | 202 +++++++++++++++++++++ 1 file changed, 202 insertions(+) create mode 100644 Documentation/networking/device_drivers/ethernet/toshiba/spider_net.rst (limited to 'Documentation/networking/device_drivers/ethernet/toshiba') diff --git a/Documentation/networking/device_drivers/ethernet/toshiba/spider_net.rst b/Documentation/networking/device_drivers/ethernet/toshiba/spider_net.rst new file mode 100644 index 000000000..fe5b32be1 --- /dev/null +++ b/Documentation/networking/device_drivers/ethernet/toshiba/spider_net.rst @@ -0,0 +1,202 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========================== +The Spidernet Device Driver +=========================== + +Written by Linas Vepstas + +Version of 7 June 2007 + +Abstract +======== +This document sketches the structure of portions of the spidernet +device driver in the Linux kernel tree. The spidernet is a gigabit +ethernet device built into the Toshiba southbridge commonly used +in the SONY Playstation 3 and the IBM QS20 Cell blade. + +The Structure of the RX Ring. +============================= +The receive (RX) ring is a circular linked list of RX descriptors, +together with three pointers into the ring that are used to manage its +contents. + +The elements of the ring are called "descriptors" or "descrs"; they +describe the received data. This includes a pointer to a buffer +containing the received data, the buffer size, and various status bits. + +There are three primary states that a descriptor can be in: "empty", +"full" and "not-in-use". An "empty" or "ready" descriptor is ready +to receive data from the hardware. A "full" descriptor has data in it, +and is waiting to be emptied and processed by the OS. A "not-in-use" +descriptor is neither empty or full; it is simply not ready. It may +not even have a data buffer in it, or is otherwise unusable. + +During normal operation, on device startup, the OS (specifically, the +spidernet device driver) allocates a set of RX descriptors and RX +buffers. These are all marked "empty", ready to receive data. This +ring is handed off to the hardware, which sequentially fills in the +buffers, and marks them "full". The OS follows up, taking the full +buffers, processing them, and re-marking them empty. + +This filling and emptying is managed by three pointers, the "head" +and "tail" pointers, managed by the OS, and a hardware current +descriptor pointer (GDACTDPA). The GDACTDPA points at the descr +currently being filled. When this descr is filled, the hardware +marks it full, and advances the GDACTDPA by one. Thus, when there is +flowing RX traffic, every descr behind it should be marked "full", +and everything in front of it should be "empty". If the hardware +discovers that the current descr is not empty, it will signal an +interrupt, and halt processing. + +The tail pointer tails or trails the hardware pointer. When the +hardware is ahead, the tail pointer will be pointing at a "full" +descr. The OS will process this descr, and then mark it "not-in-use", +and advance the tail pointer. Thus, when there is flowing RX traffic, +all of the descrs in front of the tail pointer should be "full", and +all of those behind it should be "not-in-use". When RX traffic is not +flowing, then the tail pointer can catch up to the hardware pointer. +The OS will then note that the current tail is "empty", and halt +processing. + +The head pointer (somewhat mis-named) follows after the tail pointer. +When traffic is flowing, then the head pointer will be pointing at +a "not-in-use" descr. The OS will perform various housekeeping duties +on this descr. This includes allocating a new data buffer and +dma-mapping it so as to make it visible to the hardware. The OS will +then mark the descr as "empty", ready to receive data. Thus, when there +is flowing RX traffic, everything in front of the head pointer should +be "not-in-use", and everything behind it should be "empty". If no +RX traffic is flowing, then the head pointer can catch up to the tail +pointer, at which point the OS will notice that the head descr is +"empty", and it will halt processing. + +Thus, in an idle system, the GDACTDPA, tail and head pointers will +all be pointing at the same descr, which should be "empty". All of the +other descrs in the ring should be "empty" as well. + +The show_rx_chain() routine will print out the locations of the +GDACTDPA, tail and head pointers. It will also summarize the contents +of the ring, starting at the tail pointer, and listing the status +of the descrs that follow. + +A typical example of the output, for a nearly idle system, might be:: + + net eth1: Total number of descrs=256 + net eth1: Chain tail located at descr=20 + net eth1: Chain head is at 20 + net eth1: HW curr desc (GDACTDPA) is at 21 + net eth1: Have 1 descrs with stat=x40800101 + net eth1: HW next desc (GDACNEXTDA) is at 22 + net eth1: Last 255 descrs with stat=xa0800000 + +In the above, the hardware has filled in one descr, number 20. Both +head and tail are pointing at 20, because it has not yet been emptied. +Meanwhile, hw is pointing at 21, which is free. + +The "Have nnn decrs" refers to the descr starting at the tail: in this +case, nnn=1 descr, starting at descr 20. The "Last nnn descrs" refers +to all of the rest of the descrs, from the last status change. The "nnn" +is a count of how many descrs have exactly the same status. + +The status x4... corresponds to "full" and status xa... corresponds +to "empty". The actual value printed is RXCOMST_A. + +In the device driver source code, a different set of names are +used for these same concepts, so that:: + + "empty" == SPIDER_NET_DESCR_CARDOWNED == 0xa + "full" == SPIDER_NET_DESCR_FRAME_END == 0x4 + "not in use" == SPIDER_NET_DESCR_NOT_IN_USE == 0xf + + +The RX RAM full bug/feature +=========================== + +As long as the OS can empty out the RX buffers at a rate faster than +the hardware can fill them, there is no problem. If, for some reason, +the OS fails to empty the RX ring fast enough, the hardware GDACTDPA +pointer will catch up to the head, notice the not-empty condition, +ad stop. However, RX packets may still continue arriving on the wire. +The spidernet chip can save some limited number of these in local RAM. +When this local ram fills up, the spider chip will issue an interrupt +indicating this (GHIINT0STS will show ERRINT, and the GRMFLLINT bit +will be set in GHIINT1STS). When the RX ram full condition occurs, +a certain bug/feature is triggered that has to be specially handled. +This section describes the special handling for this condition. + +When the OS finally has a chance to run, it will empty out the RX ring. +In particular, it will clear the descriptor on which the hardware had +stopped. However, once the hardware has decided that a certain +descriptor is invalid, it will not restart at that descriptor; instead +it will restart at the next descr. This potentially will lead to a +deadlock condition, as the tail pointer will be pointing at this descr, +which, from the OS point of view, is empty; the OS will be waiting for +this descr to be filled. However, the hardware has skipped this descr, +and is filling the next descrs. Since the OS doesn't see this, there +is a potential deadlock, with the OS waiting for one descr to fill, +while the hardware is waiting for a different set of descrs to become +empty. + +A call to show_rx_chain() at this point indicates the nature of the +problem. A typical print when the network is hung shows the following:: + + net eth1: Spider RX RAM full, incoming packets might be discarded! + net eth1: Total number of descrs=256 + net eth1: Chain tail located at descr=255 + net eth1: Chain head is at 255 + net eth1: HW curr desc (GDACTDPA) is at 0 + net eth1: Have 1 descrs with stat=xa0800000 + net eth1: HW next desc (GDACNEXTDA) is at 1 + net eth1: Have 127 descrs with stat=x40800101 + net eth1: Have 1 descrs with stat=x40800001 + net eth1: Have 126 descrs with stat=x40800101 + net eth1: Last 1 descrs with stat=xa0800000 + +Both the tail and head pointers are pointing at descr 255, which is +marked xa... which is "empty". Thus, from the OS point of view, there +is nothing to be done. In particular, there is the implicit assumption +that everything in front of the "empty" descr must surely also be empty, +as explained in the last section. The OS is waiting for descr 255 to +become non-empty, which, in this case, will never happen. + +The HW pointer is at descr 0. This descr is marked 0x4.. or "full". +Since its already full, the hardware can do nothing more, and thus has +halted processing. Notice that descrs 0 through 254 are all marked +"full", while descr 254 and 255 are empty. (The "Last 1 descrs" is +descr 254, since tail was at 255.) Thus, the system is deadlocked, +and there can be no forward progress; the OS thinks there's nothing +to do, and the hardware has nowhere to put incoming data. + +This bug/feature is worked around with the spider_net_resync_head_ptr() +routine. When the driver receives RX interrupts, but an examination +of the RX chain seems to show it is empty, then it is probable that +the hardware has skipped a descr or two (sometimes dozens under heavy +network conditions). The spider_net_resync_head_ptr() subroutine will +search the ring for the next full descr, and the driver will resume +operations there. Since this will leave "holes" in the ring, there +is also a spider_net_resync_tail_ptr() that will skip over such holes. + +As of this writing, the spider_net_resync() strategy seems to work very +well, even under heavy network loads. + + +The TX ring +=========== +The TX ring uses a low-watermark interrupt scheme to make sure that +the TX queue is appropriately serviced for large packet sizes. + +For packet sizes greater than about 1KBytes, the kernel can fill +the TX ring quicker than the device can drain it. Once the ring +is full, the netdev is stopped. When there is room in the ring, +the netdev needs to be reawakened, so that more TX packets are placed +in the ring. The hardware can empty the ring about four times per jiffy, +so its not appropriate to wait for the poll routine to refill, since +the poll routine runs only once per jiffy. The low-watermark mechanism +marks a descr about 1/4th of the way from the bottom of the queue, so +that an interrupt is generated when the descr is processed. This +interrupt wakes up the netdev, which can then refill the queue. +For large packets, this mechanism generates a relatively small number +of interrupts, about 1K/sec. For smaller packets, this will drop to zero +interrupts, as the hardware can empty the queue faster than the kernel +can fill it. -- cgit v1.2.3