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().
  ...

5 files changed, 415 insertions, 0 deletions

diff --git a/Documentation/arm/sa1100/assabet.rst b/Documentation/arm/sa1100/assabet.rst
new file mode 100644
index 000000000..a761e128f
--- /dev/null
+++ b/Documentation/arm/sa1100/assabet.rst
@@ -0,0 +1,301 @@
+============================================
+The Intel Assabet (SA-1110 evaluation) board
+============================================
+
+Please see:
+http://developer.intel.com
+
+Also some notes from John G Dorsey <jd5q@andrew.cmu.edu>:
+http://www.cs.cmu.edu/~wearable/software/assabet.html
+
+
+Building the kernel
+-------------------
+
+To build the kernel with current defaults::
+
+	make assabet_defconfig
+	make oldconfig
+	make zImage
+
+The resulting kernel image should be available in linux/arch/arm/boot/zImage.
+
+
+Installing a bootloader
+-----------------------
+
+A couple of bootloaders able to boot Linux on Assabet are available:
+
+BLOB (http://www.lartmaker.nl/lartware/blob/)
+
+   BLOB is a bootloader used within the LART project.  Some contributed
+   patches were merged into BLOB to add support for Assabet.
+
+Compaq's Bootldr + John Dorsey's patch for Assabet support
+(http://www.handhelds.org/Compaq/bootldr.html)
+(http://www.wearablegroup.org/software/bootldr/)
+
+   Bootldr is the bootloader developed by Compaq for the iPAQ Pocket PC.
+   John Dorsey has produced add-on patches to add support for Assabet and
+   the JFFS filesystem.
+
+RedBoot (http://sources.redhat.com/redboot/)
+
+   RedBoot is a bootloader developed by Red Hat based on the eCos RTOS
+   hardware abstraction layer.  It supports Assabet amongst many other
+   hardware platforms.
+
+RedBoot is currently the recommended choice since it's the only one to have
+networking support, and is the most actively maintained.
+
+Brief examples on how to boot Linux with RedBoot are shown below.  But first
+you need to have RedBoot installed in your flash memory.  A known to work
+precompiled RedBoot binary is available from the following location:
+
+- ftp://ftp.netwinder.org/users/n/nico/
+- ftp://ftp.arm.linux.org.uk/pub/linux/arm/people/nico/
+- ftp://ftp.handhelds.org/pub/linux/arm/sa-1100-patches/
+
+Look for redboot-assabet*.tgz.  Some installation infos are provided in
+redboot-assabet*.txt.
+
+
+Initial RedBoot configuration
+-----------------------------
+
+The commands used here are explained in The RedBoot User's Guide available
+on-line at http://sources.redhat.com/ecos/docs.html.
+Please refer to it for explanations.
+
+If you have a CF network card (my Assabet kit contained a CF+ LP-E from
+Socket Communications Inc.), you should strongly consider using it for TFTP
+file transfers.  You must insert it before RedBoot runs since it can't detect
+it dynamically.
+
+To initialize the flash directory::
+
+	fis init -f
+
+To initialize the non-volatile settings, like whether you want to use BOOTP or
+a static IP address, etc, use this command::
+
+	fconfig -i
+
+
+Writing a kernel image into flash
+---------------------------------
+
+First, the kernel image must be loaded into RAM.  If you have the zImage file
+available on a TFTP server::
+
+	load zImage -r -b 0x100000
+
+If you rather want to use Y-Modem upload over the serial port::
+
+	load -m ymodem -r -b 0x100000
+
+To write it to flash::
+
+	fis create "Linux kernel" -b 0x100000 -l 0xc0000
+
+
+Booting the kernel
+------------------
+
+The kernel still requires a filesystem to boot.  A ramdisk image can be loaded
+as follows::
+
+	load ramdisk_image.gz -r -b 0x800000
+
+Again, Y-Modem upload can be used instead of TFTP by replacing the file name
+by '-y ymodem'.
+
+Now the kernel can be retrieved from flash like this::
+
+	fis load "Linux kernel"
+
+or loaded as described previously.  To boot the kernel::
+
+	exec -b 0x100000 -l 0xc0000
+
+The ramdisk image could be stored into flash as well, but there are better
+solutions for on-flash filesystems as mentioned below.
+
+
+Using JFFS2
+-----------
+
+Using JFFS2 (the Second Journalling Flash File System) is probably the most
+convenient way to store a writable filesystem into flash.  JFFS2 is used in
+conjunction with the MTD layer which is responsible for low-level flash
+management.  More information on the Linux MTD can be found on-line at:
+http://www.linux-mtd.infradead.org/.  A JFFS howto with some infos about
+creating JFFS/JFFS2 images is available from the same site.
+
+For instance, a sample JFFS2 image can be retrieved from the same FTP sites
+mentioned below for the precompiled RedBoot image.
+
+To load this file::
+
+	load sample_img.jffs2 -r -b 0x100000
+
+The result should look like::
+
+	RedBoot> load sample_img.jffs2 -r -b 0x100000
+	Raw file loaded 0x00100000-0x00377424
+
+Now we must know the size of the unallocated flash::
+
+	fis free
+
+Result::
+
+	RedBoot> fis free
+	  0x500E0000 .. 0x503C0000
+
+The values above may be different depending on the size of the filesystem and
+the type of flash.  See their usage below as an example and take care of
+substituting yours appropriately.
+
+We must determine some values::
+
+	size of unallocated flash:	0x503c0000 - 0x500e0000 = 0x2e0000
+	size of the filesystem image:	0x00377424 - 0x00100000 = 0x277424
+
+We want to fit the filesystem image of course, but we also want to give it all
+the remaining flash space as well.  To write it::
+
+	fis unlock -f 0x500E0000 -l 0x2e0000
+	fis erase -f 0x500E0000 -l 0x2e0000
+	fis write -b 0x100000 -l 0x277424 -f 0x500E0000
+	fis create "JFFS2" -n -f 0x500E0000 -l 0x2e0000
+
+Now the filesystem is associated to a MTD "partition" once Linux has discovered
+what they are in the boot process.  From Redboot, the 'fis list' command
+displays them::
+
+	RedBoot> fis list
+	Name              FLASH addr  Mem addr    Length      Entry point
+	RedBoot           0x50000000  0x50000000  0x00020000  0x00000000
+	RedBoot config    0x503C0000  0x503C0000  0x00020000  0x00000000
+	FIS directory     0x503E0000  0x503E0000  0x00020000  0x00000000
+	Linux kernel      0x50020000  0x00100000  0x000C0000  0x00000000
+	JFFS2             0x500E0000  0x500E0000  0x002E0000  0x00000000
+
+However Linux should display something like::
+
+	SA1100 flash: probing 32-bit flash bus
+	SA1100 flash: Found 2 x16 devices at 0x0 in 32-bit mode
+	Using RedBoot partition definition
+	Creating 5 MTD partitions on "SA1100 flash":
+	0x00000000-0x00020000 : "RedBoot"
+	0x00020000-0x000e0000 : "Linux kernel"
+	0x000e0000-0x003c0000 : "JFFS2"
+	0x003c0000-0x003e0000 : "RedBoot config"
+	0x003e0000-0x00400000 : "FIS directory"
+
+What's important here is the position of the partition we are interested in,
+which is the third one.  Within Linux, this correspond to /dev/mtdblock2.
+Therefore to boot Linux with the kernel and its root filesystem in flash, we
+need this RedBoot command::
+
+	fis load "Linux kernel"
+	exec -b 0x100000 -l 0xc0000 -c "root=/dev/mtdblock2"
+
+Of course other filesystems than JFFS might be used, like cramfs for example.
+You might want to boot with a root filesystem over NFS, etc.  It is also
+possible, and sometimes more convenient, to flash a filesystem directly from
+within Linux while booted from a ramdisk or NFS.  The Linux MTD repository has
+many tools to deal with flash memory as well, to erase it for example.  JFFS2
+can then be mounted directly on a freshly erased partition and files can be
+copied over directly.  Etc...
+
+
+RedBoot scripting
+-----------------
+
+All the commands above aren't so useful if they have to be typed in every
+time the Assabet is rebooted.  Therefore it's possible to automate the boot
+process using RedBoot's scripting capability.
+
+For example, I use this to boot Linux with both the kernel and the ramdisk
+images retrieved from a TFTP server on the network::
+
+	RedBoot> fconfig
+	Run script at boot: false true
+	Boot script:
+	Enter script, terminate with empty line
+	>> load zImage -r -b 0x100000
+	>> load ramdisk_ks.gz -r -b 0x800000
+	>> exec -b 0x100000 -l 0xc0000
+	>>
+	Boot script timeout (1000ms resolution): 3
+	Use BOOTP for network configuration: true
+	GDB connection port: 9000
+	Network debug at boot time: false
+	Update RedBoot non-volatile configuration - are you sure (y/n)? y
+
+Then, rebooting the Assabet is just a matter of waiting for the login prompt.
+
+
+
+Nicolas Pitre
+nico@fluxnic.net
+
+June 12, 2001
+
+
+Status of peripherals in -rmk tree (updated 14/10/2001)
+-------------------------------------------------------
+
+Assabet:
+ Serial ports:
+  Radio:		TX, RX, CTS, DSR, DCD, RI
+   - PM:		Not tested.
+   - COM:		TX, RX, CTS, DSR, DCD, RTS, DTR, PM
+   - PM:		Not tested.
+   - I2C:		Implemented, not fully tested.
+   - L3:		Fully tested, pass.
+   - PM:		Not tested.
+
+ Video:
+  - LCD:		Fully tested.  PM
+
+   (LCD doesn't like being blanked with neponset connected)
+
+  - Video out:		Not fully
+
+ Audio:
+  UDA1341:
+  -  Playback:		Fully tested, pass.
+  -  Record:		Implemented, not tested.
+  -  PM:			Not tested.
+
+  UCB1200:
+  -  Audio play:	Implemented, not heavily tested.
+  -  Audio rec:		Implemented, not heavily tested.
+  -  Telco audio play:	Implemented, not heavily tested.
+  -  Telco audio rec:	Implemented, not heavily tested.
+  -  POTS control:	No
+  -  Touchscreen:	Yes
+  -  PM:		Not tested.
+
+ Other:
+  - PCMCIA:
+  - LPE:		Fully tested, pass.
+  - USB:		No
+  - IRDA:
+  - SIR:		Fully tested, pass.
+  - FIR:		Fully tested, pass.
+  - PM:			Not tested.
+
+Neponset:
+ Serial ports:
+  - COM1,2:		TX, RX, CTS, DSR, DCD, RTS, DTR
+  - PM:			Not tested.
+  - USB:		Implemented, not heavily tested.
+  - PCMCIA:		Implemented, not heavily tested.
+  - CF:			Implemented, not heavily tested.
+  - PM:			Not tested.
+
+More stuff can be found in the -np (Nicolas Pitre's) tree.
diff --git a/Documentation/arm/sa1100/cerf.rst b/Documentation/arm/sa1100/cerf.rst
new file mode 100644
index 000000000..7fa71b609
--- /dev/null
+++ b/Documentation/arm/sa1100/cerf.rst
@@ -0,0 +1,35 @@
+==============
+CerfBoard/Cube
+==============
+
+*** The StrongARM version of the CerfBoard/Cube has been discontinued ***
+
+The Intrinsyc CerfBoard is a StrongARM 1110-based computer on a board
+that measures approximately 2" square. It includes an Ethernet
+controller, an RS232-compatible serial port, a USB function port, and
+one CompactFlash+ slot on the back. Pictures can be found at the
+Intrinsyc website, http://www.intrinsyc.com.
+
+This document describes the support in the Linux kernel for the
+Intrinsyc CerfBoard.
+
+Supported in this version
+=========================
+
+   - CompactFlash+ slot (select PCMCIA in General Setup and any options
+     that may be required)
+   - Onboard Crystal CS8900 Ethernet controller (Cerf CS8900A support in
+     Network Devices)
+   - Serial ports with a serial console (hardcoded to 38400 8N1)
+
+In order to get this kernel onto your Cerf, you need a server that runs
+both BOOTP and TFTP. Detailed instructions should have come with your
+evaluation kit on how to use the bootloader. This series of commands
+will suffice::
+
+   make ARCH=arm CROSS_COMPILE=arm-linux- cerfcube_defconfig
+   make ARCH=arm CROSS_COMPILE=arm-linux- zImage
+   make ARCH=arm CROSS_COMPILE=arm-linux- modules
+   cp arch/arm/boot/zImage <TFTP directory>
+
+support@intrinsyc.com
diff --git a/Documentation/arm/sa1100/index.rst b/Documentation/arm/sa1100/index.rst
new file mode 100644
index 000000000..c9aed4328
--- /dev/null
+++ b/Documentation/arm/sa1100/index.rst
@@ -0,0 +1,13 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+====================
+Intel StrongARM 1100
+====================
+
+.. toctree::
+    :maxdepth: 1
+
+    assabet
+    cerf
+    lart
+    serial_uart
diff --git a/Documentation/arm/sa1100/lart.rst b/Documentation/arm/sa1100/lart.rst
new file mode 100644
index 000000000..94c0568d1
--- /dev/null
+++ b/Documentation/arm/sa1100/lart.rst
@@ -0,0 +1,15 @@
+====================================
+Linux Advanced Radio Terminal (LART)
+====================================
+
+The LART is a small (7.5 x 10cm) SA-1100 board, designed for embedded
+applications. It has 32 MB DRAM, 4MB Flash ROM, double RS232 and all
+other StrongARM-gadgets. Almost all SA signals are directly accessible
+through a number of connectors. The powersupply accepts voltages
+between 3.5V and 16V and is overdimensioned to support a range of
+daughterboards. A quad Ethernet / IDE / PS2 / sound daughterboard
+is under development, with plenty of others in different stages of
+planning.
+
+The hardware designs for this board have been released under an open license;
+see the LART page at http://www.lartmaker.nl/ for more information.
diff --git a/Documentation/arm/sa1100/serial_uart.rst b/Documentation/arm/sa1100/serial_uart.rst
new file mode 100644
index 000000000..ea983642b
--- /dev/null
+++ b/Documentation/arm/sa1100/serial_uart.rst
@@ -0,0 +1,51 @@
+==================
+SA1100 serial port
+==================
+
+The SA1100 serial port had its major/minor numbers officially assigned::
+
+  > Date: Sun, 24 Sep 2000 21:40:27 -0700
+  > From: H. Peter Anvin <hpa@transmeta.com>
+  > To: Nicolas Pitre <nico@CAM.ORG>
+  > Cc: Device List Maintainer <device@lanana.org>
+  > Subject: Re: device
+  >
+  > Okay.  Note that device numbers 204 and 205 are used for "low density
+  > serial devices", so you will have a range of minors on those majors (the
+  > tty device layer handles this just fine, so you don't have to worry about
+  > doing anything special.)
+  >
+  > So your assignments are:
+  >
+  > 204 char        Low-density serial ports
+  >                   5 = /dev/ttySA0               SA1100 builtin serial port 0
+  >                   6 = /dev/ttySA1               SA1100 builtin serial port 1
+  >                   7 = /dev/ttySA2               SA1100 builtin serial port 2
+  >
+  > 205 char        Low-density serial ports (alternate device)
+  >                   5 = /dev/cusa0                Callout device for ttySA0
+  >                   6 = /dev/cusa1                Callout device for ttySA1
+  >                   7 = /dev/cusa2                Callout device for ttySA2
+  >
+
+You must create those inodes in /dev on the root filesystem used
+by your SA1100-based device::
+
+	mknod ttySA0 c 204 5
+	mknod ttySA1 c 204 6
+	mknod ttySA2 c 204 7
+	mknod cusa0 c 205 5
+	mknod cusa1 c 205 6
+	mknod cusa2 c 205 7
+
+In addition to the creation of the appropriate device nodes above, you
+must ensure your user space applications make use of the correct device
+name. The classic example is the content of the /etc/inittab file where
+you might have a getty process started on ttyS0.
+
+In this case:
+
+- replace occurrences of ttyS0 with ttySA0, ttyS1 with ttySA1, etc.
+
+- don't forget to add 'ttySA0', 'console', or the appropriate tty name
+  in /etc/securetty for root to be allowed to login as well.