aboutsummaryrefslogtreecommitdiff
path: root/Documentation/misc-devices/oxsemi-tornado.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/misc-devices/oxsemi-tornado.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/misc-devices/oxsemi-tornado.rst131
1 files changed, 131 insertions, 0 deletions
diff --git a/Documentation/misc-devices/oxsemi-tornado.rst b/Documentation/misc-devices/oxsemi-tornado.rst
new file mode 100644
index 000000000..b33351bef
--- /dev/null
+++ b/Documentation/misc-devices/oxsemi-tornado.rst
@@ -0,0 +1,131 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+====================================================================
+Notes on Oxford Semiconductor PCIe (Tornado) 950 serial port devices
+====================================================================
+
+Oxford Semiconductor PCIe (Tornado) 950 serial port devices are driven
+by a fixed 62.5MHz clock input derived from the 100MHz PCI Express clock.
+
+The baud rate produced by the baud generator is obtained from this input
+frequency by dividing it by the clock prescaler, which can be set to any
+value from 1 to 63.875 in increments of 0.125, and then the usual 16-bit
+divisor is used as with the original 8250, to divide the frequency by a
+value from 1 to 65535. Finally a programmable oversampling rate is used
+that can take any value from 4 to 16 to divide the frequency further and
+determine the actual baud rate used. Baud rates from 15625000bps down
+to 0.933bps can be obtained this way.
+
+By default the oversampling rate is set to 16 and the clock prescaler is
+set to 33.875, meaning that the frequency to be used as the reference
+for the usual 16-bit divisor is 115313.653, which is close enough to the
+frequency of 115200 used by the original 8250 for the same values to be
+used for the divisor to obtain the requested baud rates by software that
+is unaware of the extra clock controls available.
+
+The oversampling rate is programmed with the TCR register and the clock
+prescaler is programmed with the CPR/CPR2 register pair [OX200]_ [OX952]_
+[OX954]_ [OX958]_. To switch away from the default value of 33.875 for
+the prescaler the enhanced mode has to be explicitly enabled though, by
+setting bit 4 of the EFR. In that mode setting bit 7 in the MCR enables
+the prescaler or otherwise it is bypassed as if the value of 1 was used.
+Additionally writing any value to CPR clears CPR2 for compatibility with
+old software written for older conventional PCI Oxford Semiconductor
+devices that do not have the extra prescaler's 9th bit in CPR2, so the
+CPR/CPR2 register pair has to be programmed in the right order.
+
+By using these parameters rates from 15625000bps down to 1bps can be
+obtained, with either exact or highly-accurate actual bit rates for
+standard and many non-standard rates.
+
+Here are the figures for the standard and some non-standard baud rates
+(including those quoted in Oxford Semiconductor documentation), giving
+the requested rate (r), the actual rate yielded (a) and its deviation
+from the requested rate (d), and the values of the oversampling rate
+(tcr), the clock prescaler (cpr) and the divisor (div) produced by the
+new ``get_divisor`` handler:
+
+::
+
+ r: 15625000, a: 15625000.00, d: 0.0000%, tcr: 4, cpr: 1.000, div: 1
+ r: 12500000, a: 12500000.00, d: 0.0000%, tcr: 5, cpr: 1.000, div: 1
+ r: 10416666, a: 10416666.67, d: 0.0000%, tcr: 6, cpr: 1.000, div: 1
+ r: 8928571, a: 8928571.43, d: 0.0000%, tcr: 7, cpr: 1.000, div: 1
+ r: 7812500, a: 7812500.00, d: 0.0000%, tcr: 8, cpr: 1.000, div: 1
+ r: 4000000, a: 4000000.00, d: 0.0000%, tcr: 5, cpr: 3.125, div: 1
+ r: 3686400, a: 3676470.59, d: -0.2694%, tcr: 8, cpr: 2.125, div: 1
+ r: 3500000, a: 3496503.50, d: -0.0999%, tcr: 13, cpr: 1.375, div: 1
+ r: 3000000, a: 2976190.48, d: -0.7937%, tcr: 14, cpr: 1.500, div: 1
+ r: 2500000, a: 2500000.00, d: 0.0000%, tcr: 10, cpr: 2.500, div: 1
+ r: 2000000, a: 2000000.00, d: 0.0000%, tcr: 10, cpr: 3.125, div: 1
+ r: 1843200, a: 1838235.29, d: -0.2694%, tcr: 16, cpr: 2.125, div: 1
+ r: 1500000, a: 1492537.31, d: -0.4975%, tcr: 5, cpr: 8.375, div: 1
+ r: 1152000, a: 1152073.73, d: 0.0064%, tcr: 14, cpr: 3.875, div: 1
+ r: 921600, a: 919117.65, d: -0.2694%, tcr: 16, cpr: 2.125, div: 2
+ r: 576000, a: 576036.87, d: 0.0064%, tcr: 14, cpr: 3.875, div: 2
+ r: 460800, a: 460829.49, d: 0.0064%, tcr: 7, cpr: 3.875, div: 5
+ r: 230400, a: 230414.75, d: 0.0064%, tcr: 14, cpr: 3.875, div: 5
+ r: 115200, a: 115207.37, d: 0.0064%, tcr: 14, cpr: 1.250, div: 31
+ r: 57600, a: 57603.69, d: 0.0064%, tcr: 8, cpr: 3.875, div: 35
+ r: 38400, a: 38402.46, d: 0.0064%, tcr: 14, cpr: 3.875, div: 30
+ r: 19200, a: 19201.23, d: 0.0064%, tcr: 8, cpr: 3.875, div: 105
+ r: 9600, a: 9600.06, d: 0.0006%, tcr: 9, cpr: 1.125, div: 643
+ r: 4800, a: 4799.98, d: -0.0004%, tcr: 7, cpr: 2.875, div: 647
+ r: 2400, a: 2400.02, d: 0.0008%, tcr: 9, cpr: 2.250, div: 1286
+ r: 1200, a: 1200.00, d: 0.0000%, tcr: 14, cpr: 2.875, div: 1294
+ r: 300, a: 300.00, d: 0.0000%, tcr: 11, cpr: 2.625, div: 7215
+ r: 200, a: 200.00, d: 0.0000%, tcr: 16, cpr: 1.250, div: 15625
+ r: 150, a: 150.00, d: 0.0000%, tcr: 13, cpr: 2.250, div: 14245
+ r: 134, a: 134.00, d: 0.0000%, tcr: 11, cpr: 2.625, div: 16153
+ r: 110, a: 110.00, d: 0.0000%, tcr: 12, cpr: 1.000, div: 47348
+ r: 75, a: 75.00, d: 0.0000%, tcr: 4, cpr: 5.875, div: 35461
+ r: 50, a: 50.00, d: 0.0000%, tcr: 16, cpr: 1.250, div: 62500
+ r: 25, a: 25.00, d: 0.0000%, tcr: 16, cpr: 2.500, div: 62500
+ r: 4, a: 4.00, d: 0.0000%, tcr: 16, cpr: 20.000, div: 48828
+ r: 2, a: 2.00, d: 0.0000%, tcr: 16, cpr: 40.000, div: 48828
+ r: 1, a: 1.00, d: 0.0000%, tcr: 16, cpr: 63.875, div: 61154
+
+With the baud base set to 15625000 and the unsigned 16-bit UART_DIV_MAX
+limitation imposed by ``serial8250_get_baud_rate`` standard baud rates
+below 300bps become unavailable in the regular way, e.g. the rate of
+200bps requires the baud base to be divided by 78125 and that is beyond
+the unsigned 16-bit range. The historic spd_cust feature can still be
+used by encoding the values for, the prescaler, the oversampling rate
+and the clock divisor (DLM/DLL) as follows to obtain such rates if so
+required:
+
+::
+
+ 31 29 28 20 19 16 15 0
+ +-----+-----------------+-------+-------------------------------+
+ |0 0 0| CPR2:CPR | TCR | DLM:DLL |
+ +-----+-----------------+-------+-------------------------------+
+
+Use a value such encoded for the ``custom_divisor`` field along with the
+ASYNC_SPD_CUST flag set in the ``flags`` field in ``struct serial_struct``
+passed with the TIOCSSERIAL ioctl(2), such as with the setserial(8)
+utility and its ``divisor`` and ``spd_cust`` parameters, and then select
+the baud rate of 38400bps. Note that the value of 0 in TCR sets the
+oversampling rate to 16 and prescaler values below 1 in CPR2/CPR are
+clamped by the driver to 1.
+
+For example the value of 0x1f4004e2 will set CPR2/CPR, TCR and DLM/DLL
+respectively to 0x1f4, 0x0 and 0x04e2, choosing the prescaler value,
+the oversampling rate and the clock divisor of 62.500, 16 and 1250
+respectively. These parameters will set the baud rate for the serial
+port to 62500000 / 62.500 / 1250 / 16 = 50bps.
+
+Maciej W. Rozycki <macro@orcam.me.uk>
+
+.. [OX200] "OXPCIe200 PCI Express Multi-Port Bridge", Oxford Semiconductor,
+ Inc., DS-0045, 10 Nov 2008, Section "950 Mode", pp. 64-65
+
+.. [OX952] "OXPCIe952 PCI Express Bridge to Dual Serial & Parallel Port",
+ Oxford Semiconductor, Inc., DS-0046, Mar 06 08, Section "950 Mode",
+ p. 20
+
+.. [OX954] "OXPCIe954 PCI Express Bridge to Quad Serial Port", Oxford
+ Semiconductor, Inc., DS-0047, Feb 08, Section "950 Mode", p. 20
+
+.. [OX958] "OXPCIe958 PCI Express Bridge to Octal Serial Port", Oxford
+ Semiconductor, Inc., DS-0048, Feb 08, Section "950 Mode", p. 20