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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
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treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /arch/m68k/q40/README
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Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
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(). ...
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+Linux for the Q40
+=================
+
+You may try http://www.geocities.com/SiliconValley/Bay/2602/ for
+some up to date information. Booter and other tools will be also
+available from this place or http://ftp.uni-erlangen.de/pub/unix/Linux/680x0/q40/
+and mirrors.
+
+Hints to documentation usually refer to the linux source tree in
+/usr/src/linux/Documentation unless URL given.
+
+It seems IRQ unmasking can't be safely done on a Q40. IRQ probing
+is not implemented - do not try it! (See below)
+
+For a list of kernel command-line options read the documentation for the
+particular device drivers.
+
+The floppy imposes a very high interrupt load on the CPU, approx 30K/s.
+When something blocks interrupts (HD) it will lose some of them, so far
+this is not known to have caused any data loss. On highly loaded systems
+it can make the floppy very slow or practically stop. Other Q40 OS' simply
+poll the floppy for this reason - something that can't be done in Linux.
+Only possible cure is getting a 82072 controller with fifo instead of
+the 8272A.
+
+drivers used by the Q40, apart from the very obvious (console etc.):
+ drivers/char/q40_keyb.c # use PC keymaps for national keyboards
+ serial.c # normal PC driver - any speed
+ lp.c # printer driver
+ genrtc.c # RTC
+ char/joystick/* # most of this should work, not
+ # in default config.in
+ block/floppy.c # normal PC driver, DMA emu in asm/floppy.h
+ # and arch/m68k/kernel/entry.S
+ # see drivers/block/README.fd
+ ata/pata_falcon.c
+ net/ne.c
+ video/q40fb.c
+ parport/*
+ sound/dmasound_core.c
+ dmasound_q40.c
+
+Various other PC drivers can be enabled simply by adding them to
+arch/m68k/config.in, especially 8 bit devices should be without any
+problems. For cards using 16bit io/mem more care is required, like
+checking byte order issues, hacking memcpy_*_io etc.
+
+
+Debugging
+=========
+
+Upon startup the kernel will usually output "ABCQGHIJ" into the SRAM,
+preceded by the booter signature. This is a trace just in case something
+went wrong during earliest setup stages of head.S.
+**Changed** to preserve SRAM contents by default, this is only done when
+requested - SRAM must start with '%LX$' signature to do this. '-d' option
+to 'lxx' loader enables this.
+
+SRAM can also be used as additional console device, use debug=mem.
+This will save kernel startup msgs into SRAM, the screen will display
+only the penguin - and shell prompt if it gets that far..
+Unfortunately only 2000 bytes are available.
+
+Serial console works and can also be used for debugging, see loader_txt
+
+Most problems seem to be caused by fawlty or badly configured io-cards or
+hard drives anyway.
+Make sure to configure the parallel port as SPP and remove IRQ/DMA jumpers
+for first testing. The Q40 does not support DMA and may have trouble with
+parallel ports version of interrupts.
+
+
+Q40 Hardware Description
+========================
+
+This is just an overview, see asm-m68k/* for details ask if you have any
+questions.
+
+The Q40 consists of a 68040@40 MHz, 1MB video RAM, up to 32MB RAM, AT-style
+keyboard interface, 1 Programmable LED, 2x8bit DACs and up to 1MB ROM, 1MB
+shadow ROM.
+The Q60 has any of 68060 or 68LC060 and up to 128 MB RAM.
+
+Most interfacing like floppy, IDE, serial and parallel ports is done via ISA
+slots. The ISA io and mem range is mapped (sparse&byteswapped!) into separate
+regions of the memory.
+The main interrupt register IIRQ_REG will indicate whether an IRQ was internal
+or from some ISA devices, EIRQ_REG can distinguish up to 8 ISA IRQs.
+
+The Q40 custom chip is programmable to provide 2 periodic timers:
+ - 50 or 200 Hz - level 2, !!THIS CAN'T BE DISABLED!!
+ - 10 or 20 KHz - level 4, used for dma-sound
+
+Linux uses the 200 Hz interrupt for timer and beep by default.
+
+
+Interrupts
+==========
+
+q40 master chip handles only a subset of level triggered interrupts.
+
+Linux has some requirements wrt interrupt architecture, these are
+to my knowledge:
+ (a) interrupt handler must not be reentered even when sti() is called
+ from within handler
+ (b) working enable/disable_irq
+
+Luckily these requirements are only important for drivers shared
+with other architectures - ide,serial,parallel, ethernet.
+q40ints.c now contains a trivial hack for (a), (b) is more difficult
+because only irq's 4-15 can be disabled - and only all of them at once.
+Thus disable_irq() can effectively block the machine if the driver goes
+asleep.
+One thing to keep in mind when hacking around the interrupt code is
+that there is no way to find out which IRQ caused a request, [EI]IRQ_REG
+displays current state of the various IRQ lines.
+
+Keyboard
+========
+
+q40 receives AT make/break codes from the keyboard, these are translated to
+the PC scancodes x86 Linux uses. So by theory every national keyboard should
+work just by loading the appropriate x86 keytable - see any national-HOWTO.
+
+Unfortunately the AT->PC translation isn't quite trivial and even worse, my
+documentation of it is absolutely minimal - thus some exotic keys may not
+behave exactly as expected.
+
+There is still hope that it can be fixed completely though. If you encounter
+problems, email me ideally this:
+ - exact keypress/release sequence
+ - 'showkey -s' run on q40, non-X session
+ - 'showkey -s' run on a PC, non-X session
+ - AT codes as displayed by the q40 debugging ROM
+btw if the showkey output from PC and Q40 doesn't differ then you have some
+classic configuration problem - don't send me anything in this case
+