diff options
author | 2023-02-21 18:24:12 -0800 | |
---|---|---|
committer | 2023-02-21 18:24:12 -0800 | |
commit | 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch) | |
tree | cc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/driver-api/i3c | |
download | linux-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 'Documentation/driver-api/i3c')
-rw-r--r-- | Documentation/driver-api/i3c/device-driver-api.rst | 9 | ||||
-rw-r--r-- | Documentation/driver-api/i3c/index.rst | 11 | ||||
-rw-r--r-- | Documentation/driver-api/i3c/master-driver-api.rst | 9 | ||||
-rw-r--r-- | Documentation/driver-api/i3c/protocol.rst | 203 |
4 files changed, 232 insertions, 0 deletions
diff --git a/Documentation/driver-api/i3c/device-driver-api.rst b/Documentation/driver-api/i3c/device-driver-api.rst new file mode 100644 index 000000000..85bc3381c --- /dev/null +++ b/Documentation/driver-api/i3c/device-driver-api.rst @@ -0,0 +1,9 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +I3C device driver API +===================== + +.. kernel-doc:: include/linux/i3c/device.h + +.. kernel-doc:: drivers/i3c/device.c diff --git a/Documentation/driver-api/i3c/index.rst b/Documentation/driver-api/i3c/index.rst new file mode 100644 index 000000000..783d6dad0 --- /dev/null +++ b/Documentation/driver-api/i3c/index.rst @@ -0,0 +1,11 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============= +I3C subsystem +============= + +.. toctree:: + + protocol + device-driver-api + master-driver-api diff --git a/Documentation/driver-api/i3c/master-driver-api.rst b/Documentation/driver-api/i3c/master-driver-api.rst new file mode 100644 index 000000000..332552b28 --- /dev/null +++ b/Documentation/driver-api/i3c/master-driver-api.rst @@ -0,0 +1,9 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================ +I3C master controller driver API +================================ + +.. kernel-doc:: drivers/i3c/master.c + +.. kernel-doc:: include/linux/i3c/master.h diff --git a/Documentation/driver-api/i3c/protocol.rst b/Documentation/driver-api/i3c/protocol.rst new file mode 100644 index 000000000..02653defa --- /dev/null +++ b/Documentation/driver-api/i3c/protocol.rst @@ -0,0 +1,203 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============ +I3C protocol +============ + +Disclaimer +========== + +This chapter will focus on aspects that matter to software developers. For +everything hardware related (like how things are transmitted on the bus, how +collisions are prevented, ...) please have a look at the I3C specification. + +This document is just a brief introduction to the I3C protocol and the concepts +it brings to the table. If you need more information, please refer to the MIPI +I3C specification (can be downloaded here +https://resources.mipi.org/mipi-i3c-v1-download). + +Introduction +============ + +The I3C (pronounced 'eye-three-see') is a MIPI standardized protocol designed +to overcome I2C limitations (limited speed, external signals needed for +interrupts, no automatic detection of the devices connected to the bus, ...) +while remaining power-efficient. + +I3C Bus +======= + +An I3C bus is made of several I3C devices and possibly some I2C devices as +well, but let's focus on I3C devices for now. + +An I3C device on the I3C bus can have one of the following roles: + +* Master: the device is driving the bus. It's the one in charge of initiating + transactions or deciding who is allowed to talk on the bus (slave generated + events are possible in I3C, see below). +* Slave: the device acts as a slave, and is not able to send frames to another + slave on the bus. The device can still send events to the master on + its own initiative if the master allowed it. + +I3C is a multi-master protocol, so there might be several masters on a bus, +though only one device can act as a master at a given time. In order to gain +bus ownership, a master has to follow a specific procedure. + +Each device on the I3C bus has to be assigned a dynamic address to be able to +communicate. Until this is done, the device should only respond to a limited +set of commands. If it has a static address (also called legacy I2C address), +the device can reply to I2C transfers. + +In addition to these per-device addresses, the protocol defines a broadcast +address in order to address all devices on the bus. + +Once a dynamic address has been assigned to a device, this address will be used +for any direct communication with the device. Note that even after being +assigned a dynamic address, the device should still process broadcast messages. + +I3C Device discovery +==================== + +The I3C protocol defines a mechanism to automatically discover devices present +on the bus, their capabilities and the functionalities they provide. In this +regard I3C is closer to a discoverable bus like USB than it is to I2C or SPI. + +The discovery mechanism is called DAA (Dynamic Address Assignment), because it +not only discovers devices but also assigns them a dynamic address. + +During DAA, each I3C device reports 3 important things: + +* BCR: Bus Characteristic Register. This 8-bit register describes the device bus + related capabilities +* DCR: Device Characteristic Register. This 8-bit register describes the + functionalities provided by the device +* Provisional ID: A 48-bit unique identifier. On a given bus there should be no + Provisional ID collision, otherwise the discovery mechanism may fail. + +I3C slave events +================ + +The I3C protocol allows slaves to generate events on their own, and thus allows +them to take temporary control of the bus. + +This mechanism is called IBI for In Band Interrupts, and as stated in the name, +it allows devices to generate interrupts without requiring an external signal. + +During DAA, each device on the bus has been assigned an address, and this +address will serve as a priority identifier to determine who wins if 2 different +devices are generating an interrupt at the same moment on the bus (the lower the +dynamic address the higher the priority). + +Masters are allowed to inhibit interrupts if they want to. This inhibition +request can be broadcast (applies to all devices) or sent to a specific +device. + +I3C Hot-Join +============ + +The Hot-Join mechanism is similar to USB hotplug. This mechanism allows +slaves to join the bus after it has been initialized by the master. + +This covers the following use cases: + +* the device is not powered when the bus is probed +* the device is hotplugged on the bus through an extension board + +This mechanism is relying on slave events to inform the master that a new +device joined the bus and is waiting for a dynamic address. + +The master is then free to address the request as it wishes: ignore it or +assign a dynamic address to the slave. + +I3C transfer types +================== + +If you omit SMBus (which is just a standardization on how to access registers +exposed by I2C devices), I2C has only one transfer type. + +I3C defines 3 different classes of transfer in addition to I2C transfers which +are here for backward compatibility with I2C devices. + +I3C CCC commands +---------------- + +CCC (Common Command Code) commands are meant to be used for anything that is +related to bus management and all features that are common to a set of devices. + +CCC commands contain an 8-bit CCC ID describing the command that is executed. +The MSB of this ID specifies whether this is a broadcast command (bit7 = 0) or a +unicast one (bit7 = 1). + +The command ID can be followed by a payload. Depending on the command, this +payload is either sent by the master sending the command (write CCC command), +or sent by the slave receiving the command (read CCC command). Of course, read +accesses only apply to unicast commands. +Note that, when sending a CCC command to a specific device, the device address +is passed in the first byte of the payload. + +The payload length is not explicitly passed on the bus, and should be extracted +from the CCC ID. + +Note that vendors can use a dedicated range of CCC IDs for their own commands +(0x61-0x7f and 0xe0-0xef). + +I3C Private SDR transfers +------------------------- + +Private SDR (Single Data Rate) transfers should be used for anything that is +device specific and does not require high transfer speed. + +It is the equivalent of I2C transfers but in the I3C world. Each transfer is +passed the device address (dynamic address assigned during DAA), a payload +and a direction. + +The only difference with I2C is that the transfer is much faster (typical clock +frequency is 12.5MHz). + +I3C HDR commands +---------------- + +HDR commands should be used for anything that is device specific and requires +high transfer speed. + +The first thing attached to an HDR command is the HDR mode. There are currently +3 different modes defined by the I3C specification (refer to the specification +for more details): + +* HDR-DDR: Double Data Rate mode +* HDR-TSP: Ternary Symbol Pure. Only usable on busses with no I2C devices +* HDR-TSL: Ternary Symbol Legacy. Usable on busses with I2C devices + +When sending an HDR command, the whole bus has to enter HDR mode, which is done +using a broadcast CCC command. +Once the bus has entered a specific HDR mode, the master sends the HDR command. +An HDR command is made of: + +* one 16-bits command word in big endian +* N 16-bits data words in big endian + +Those words may be wrapped with specific preambles/post-ambles which depend on +the chosen HDR mode and are detailed here (see the specification for more +details). + +The 16-bits command word is made of: + +* bit[15]: direction bit, read is 1, write is 0 +* bit[14:8]: command code. Identifies the command being executed, the amount of + data words and their meaning +* bit[7:1]: I3C address of the device this command is addressed to +* bit[0]: reserved/parity-bit + +Backward compatibility with I2C devices +======================================= + +The I3C protocol has been designed to be backward compatible with I2C devices. +This backward compatibility allows one to connect a mix of I2C and I3C devices +on the same bus, though, in order to be really efficient, I2C devices should +be equipped with 50 ns spike filters. + +I2C devices can't be discovered like I3C ones and have to be statically +declared. In order to let the master know what these devices are capable of +(both in terms of bus related limitations and functionalities), the software +has to provide some information, which is done through the LVR (Legacy I2C +Virtual Register). |