aboutsummaryrefslogtreecommitdiff
path: root/Documentation/ia64/serial.rst
diff options
context:
space:
mode:
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
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/ia64/serial.rst
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip
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(). ...
Diffstat (limited to '')
-rw-r--r--Documentation/ia64/serial.rst165
1 files changed, 165 insertions, 0 deletions
diff --git a/Documentation/ia64/serial.rst b/Documentation/ia64/serial.rst
new file mode 100644
index 000000000..1de70c305
--- /dev/null
+++ b/Documentation/ia64/serial.rst
@@ -0,0 +1,165 @@
+==============
+Serial Devices
+==============
+
+Serial Device Naming
+====================
+
+ As of 2.6.10, serial devices on ia64 are named based on the
+ order of ACPI and PCI enumeration. The first device in the
+ ACPI namespace (if any) becomes /dev/ttyS0, the second becomes
+ /dev/ttyS1, etc., and PCI devices are named sequentially
+ starting after the ACPI devices.
+
+ Prior to 2.6.10, there were confusing exceptions to this:
+
+ - Firmware on some machines (mostly from HP) provides an HCDP
+ table[1] that tells the kernel about devices that can be used
+ as a serial console. If the user specified "console=ttyS0"
+ or the EFI ConOut path contained only UART devices, the
+ kernel registered the device described by the HCDP as
+ /dev/ttyS0.
+
+ - If there was no HCDP, we assumed there were UARTs at the
+ legacy COM port addresses (I/O ports 0x3f8 and 0x2f8), so
+ the kernel registered those as /dev/ttyS0 and /dev/ttyS1.
+
+ Any additional ACPI or PCI devices were registered sequentially
+ after /dev/ttyS0 as they were discovered.
+
+ With an HCDP, device names changed depending on EFI configuration
+ and "console=" arguments. Without an HCDP, device names didn't
+ change, but we registered devices that might not really exist.
+
+ For example, an HP rx1600 with a single built-in serial port
+ (described in the ACPI namespace) plus an MP[2] (a PCI device) has
+ these ports:
+
+ ========== ========== ============ ============ =======
+ Type MMIO pre-2.6.10 pre-2.6.10 2.6.10+
+ address
+ (EFI console (EFI console
+ on builtin) on MP port)
+ ========== ========== ============ ============ =======
+ builtin 0xff5e0000 ttyS0 ttyS1 ttyS0
+ MP UPS 0xf8031000 ttyS1 ttyS2 ttyS1
+ MP Console 0xf8030000 ttyS2 ttyS0 ttyS2
+ MP 2 0xf8030010 ttyS3 ttyS3 ttyS3
+ MP 3 0xf8030038 ttyS4 ttyS4 ttyS4
+ ========== ========== ============ ============ =======
+
+Console Selection
+=================
+
+ EFI knows what your console devices are, but it doesn't tell the
+ kernel quite enough to actually locate them. The DIG64 HCDP
+ table[1] does tell the kernel where potential serial console
+ devices are, but not all firmware supplies it. Also, EFI supports
+ multiple simultaneous consoles and doesn't tell the kernel which
+ should be the "primary" one.
+
+ So how do you tell Linux which console device to use?
+
+ - If your firmware supplies the HCDP, it is simplest to
+ configure EFI with a single device (either a UART or a VGA
+ card) as the console. Then you don't need to tell Linux
+ anything; the kernel will automatically use the EFI console.
+
+ (This works only in 2.6.6 or later; prior to that you had
+ to specify "console=ttyS0" to get a serial console.)
+
+ - Without an HCDP, Linux defaults to a VGA console unless you
+ specify a "console=" argument.
+
+ NOTE: Don't assume that a serial console device will be /dev/ttyS0.
+ It might be ttyS1, ttyS2, etc. Make sure you have the appropriate
+ entries in /etc/inittab (for getty) and /etc/securetty (to allow
+ root login).
+
+Early Serial Console
+====================
+
+ The kernel can't start using a serial console until it knows where
+ the device lives. Normally this happens when the driver enumerates
+ all the serial devices, which can happen a minute or more after the
+ kernel starts booting.
+
+ 2.6.10 and later kernels have an "early uart" driver that works
+ very early in the boot process. The kernel will automatically use
+ this if the user supplies an argument like "console=uart,io,0x3f8",
+ or if the EFI console path contains only a UART device and the
+ firmware supplies an HCDP.
+
+Troubleshooting Serial Console Problems
+=======================================
+
+ No kernel output after elilo prints "Uncompressing Linux... done":
+
+ - You specified "console=ttyS0" but Linux changed the device
+ to which ttyS0 refers. Configure exactly one EFI console
+ device[3] and remove the "console=" option.
+
+ - The EFI console path contains both a VGA device and a UART.
+ EFI and elilo use both, but Linux defaults to VGA. Remove
+ the VGA device from the EFI console path[3].
+
+ - Multiple UARTs selected as EFI console devices. EFI and
+ elilo use all selected devices, but Linux uses only one.
+ Make sure only one UART is selected in the EFI console
+ path[3].
+
+ - You're connected to an HP MP port[2] but have a non-MP UART
+ selected as EFI console device. EFI uses the MP as a
+ console device even when it isn't explicitly selected.
+ Either move the console cable to the non-MP UART, or change
+ the EFI console path[3] to the MP UART.
+
+ Long pause (60+ seconds) between "Uncompressing Linux... done" and
+ start of kernel output:
+
+ - No early console because you used "console=ttyS<n>". Remove
+ the "console=" option if your firmware supplies an HCDP.
+
+ - If you don't have an HCDP, the kernel doesn't know where
+ your console lives until the driver discovers serial
+ devices. Use "console=uart,io,0x3f8" (or appropriate
+ address for your machine).
+
+ Kernel and init script output works fine, but no "login:" prompt:
+
+ - Add getty entry to /etc/inittab for console tty. Look for
+ the "Adding console on ttyS<n>" message that tells you which
+ device is the console.
+
+ "login:" prompt, but can't login as root:
+
+ - Add entry to /etc/securetty for console tty.
+
+ No ACPI serial devices found in 2.6.17 or later:
+
+ - Turn on CONFIG_PNP and CONFIG_PNPACPI. Prior to 2.6.17, ACPI
+ serial devices were discovered by 8250_acpi. In 2.6.17,
+ 8250_acpi was replaced by the combination of 8250_pnp and
+ CONFIG_PNPACPI.
+
+
+
+[1]
+ http://www.dig64.org/specifications/agreement
+ The table was originally defined as the "HCDP" for "Headless
+ Console/Debug Port." The current version is the "PCDP" for
+ "Primary Console and Debug Port Devices."
+
+[2]
+ The HP MP (management processor) is a PCI device that provides
+ several UARTs. One of the UARTs is often used as a console; the
+ EFI Boot Manager identifies it as "Acpi(HWP0002,700)/Pci(...)/Uart".
+ The external connection is usually a 25-pin connector, and a
+ special dongle converts that to three 9-pin connectors, one of
+ which is labelled "Console."
+
+[3]
+ EFI console devices are configured using the EFI Boot Manager
+ "Boot option maintenance" menu. You may have to interrupt the
+ boot sequence to use this menu, and you will have to reset the
+ box after changing console configuration.