From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 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(). ... --- Documentation/spi/pxa2xx.rst | 214 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 214 insertions(+) create mode 100644 Documentation/spi/pxa2xx.rst (limited to 'Documentation/spi/pxa2xx.rst') diff --git a/Documentation/spi/pxa2xx.rst b/Documentation/spi/pxa2xx.rst new file mode 100644 index 000000000..716f65d87 --- /dev/null +++ b/Documentation/spi/pxa2xx.rst @@ -0,0 +1,214 @@ +============================== +PXA2xx SPI on SSP driver HOWTO +============================== + +This a mini HOWTO on the pxa2xx_spi driver. The driver turns a PXA2xx +synchronous serial port into an SPI master controller +(see Documentation/spi/spi-summary.rst). The driver has the following features + +- Support for any PXA2xx and compatible SSP. +- SSP PIO and SSP DMA data transfers. +- External and Internal (SSPFRM) chip selects. +- Per slave device (chip) configuration. +- Full suspend, freeze, resume support. + +The driver is built around a &struct spi_message FIFO serviced by kernel +thread. The kernel thread, spi_pump_messages(), drives message FIFO and +is responsible for queuing SPI transactions and setting up and launching +the DMA or interrupt driven transfers. + +Declaring PXA2xx Master Controllers +----------------------------------- +Typically, for a legacy platform, an SPI master is defined in the +arch/.../mach-*/board-*.c as a "platform device". The master configuration +is passed to the driver via a table found in include/linux/spi/pxa2xx_spi.h:: + + struct pxa2xx_spi_controller { + u16 num_chipselect; + u8 enable_dma; + ... + }; + +The "pxa2xx_spi_controller.num_chipselect" field is used to determine the number of +slave device (chips) attached to this SPI master. + +The "pxa2xx_spi_controller.enable_dma" field informs the driver that SSP DMA should +be used. This caused the driver to acquire two DMA channels: Rx channel and +Tx channel. The Rx channel has a higher DMA service priority than the Tx channel. +See the "PXA2xx Developer Manual" section "DMA Controller". + +For the new platforms the description of the controller and peripheral devices +comes from Device Tree or ACPI. + +NSSP MASTER SAMPLE +------------------ +Below is a sample configuration using the PXA255 NSSP for a legacy platform:: + + static struct resource pxa_spi_nssp_resources[] = { + [0] = { + .start = __PREG(SSCR0_P(2)), /* Start address of NSSP */ + .end = __PREG(SSCR0_P(2)) + 0x2c, /* Range of registers */ + .flags = IORESOURCE_MEM, + }, + [1] = { + .start = IRQ_NSSP, /* NSSP IRQ */ + .end = IRQ_NSSP, + .flags = IORESOURCE_IRQ, + }, + }; + + static struct pxa2xx_spi_controller pxa_nssp_master_info = { + .num_chipselect = 1, /* Matches the number of chips attached to NSSP */ + .enable_dma = 1, /* Enables NSSP DMA */ + }; + + static struct platform_device pxa_spi_nssp = { + .name = "pxa2xx-spi", /* MUST BE THIS VALUE, so device match driver */ + .id = 2, /* Bus number, MUST MATCH SSP number 1..n */ + .resource = pxa_spi_nssp_resources, + .num_resources = ARRAY_SIZE(pxa_spi_nssp_resources), + .dev = { + .platform_data = &pxa_nssp_master_info, /* Passed to driver */ + }, + }; + + static struct platform_device *devices[] __initdata = { + &pxa_spi_nssp, + }; + + static void __init board_init(void) + { + (void)platform_add_device(devices, ARRAY_SIZE(devices)); + } + +Declaring Slave Devices +----------------------- +Typically, for a legacy platform, each SPI slave (chip) is defined in the +arch/.../mach-*/board-*.c using the "spi_board_info" structure found in +"linux/spi/spi.h". See "Documentation/spi/spi-summary.rst" for additional +information. + +Each slave device attached to the PXA must provide slave specific configuration +information via the structure "pxa2xx_spi_chip" found in +"include/linux/spi/pxa2xx_spi.h". The pxa2xx_spi master controller driver +will uses the configuration whenever the driver communicates with the slave +device. All fields are optional. + +:: + + struct pxa2xx_spi_chip { + u8 tx_threshold; + u8 rx_threshold; + u8 dma_burst_size; + u32 timeout; + }; + +The "pxa2xx_spi_chip.tx_threshold" and "pxa2xx_spi_chip.rx_threshold" fields are +used to configure the SSP hardware FIFO. These fields are critical to the +performance of pxa2xx_spi driver and misconfiguration will result in rx +FIFO overruns (especially in PIO mode transfers). Good default values are:: + + .tx_threshold = 8, + .rx_threshold = 8, + +The range is 1 to 16 where zero indicates "use default". + +The "pxa2xx_spi_chip.dma_burst_size" field is used to configure PXA2xx DMA +engine and is related the "spi_device.bits_per_word" field. Read and understand +the PXA2xx "Developer Manual" sections on the DMA controller and SSP Controllers +to determine the correct value. An SSP configured for byte-wide transfers would +use a value of 8. The driver will determine a reasonable default if +dma_burst_size == 0. + +The "pxa2xx_spi_chip.timeout" fields is used to efficiently handle +trailing bytes in the SSP receiver FIFO. The correct value for this field is +dependent on the SPI bus speed ("spi_board_info.max_speed_hz") and the specific +slave device. Please note that the PXA2xx SSP 1 does not support trailing byte +timeouts and must busy-wait any trailing bytes. + +NOTE: the SPI driver cannot control the chip select if SSPFRM is used, so the +chipselect is dropped after each spi_transfer. Most devices need chip select +asserted around the complete message. Use SSPFRM as a GPIO (through a descriptor) +to accommodate these chips. + + +NSSP SLAVE SAMPLE +----------------- +For a legacy platform or in some other cases, the pxa2xx_spi_chip structure +is passed to the pxa2xx_spi driver in the "spi_board_info.controller_data" +field. Below is a sample configuration using the PXA255 NSSP. + +:: + + static struct pxa2xx_spi_chip cs8415a_chip_info = { + .tx_threshold = 8, /* SSP hardward FIFO threshold */ + .rx_threshold = 8, /* SSP hardward FIFO threshold */ + .dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */ + .timeout = 235, /* See Intel documentation */ + }; + + static struct pxa2xx_spi_chip cs8405a_chip_info = { + .tx_threshold = 8, /* SSP hardward FIFO threshold */ + .rx_threshold = 8, /* SSP hardward FIFO threshold */ + .dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */ + .timeout = 235, /* See Intel documentation */ + }; + + static struct spi_board_info streetracer_spi_board_info[] __initdata = { + { + .modalias = "cs8415a", /* Name of spi_driver for this device */ + .max_speed_hz = 3686400, /* Run SSP as fast a possbile */ + .bus_num = 2, /* Framework bus number */ + .chip_select = 0, /* Framework chip select */ + .platform_data = NULL; /* No spi_driver specific config */ + .controller_data = &cs8415a_chip_info, /* Master chip config */ + .irq = STREETRACER_APCI_IRQ, /* Slave device interrupt */ + }, + { + .modalias = "cs8405a", /* Name of spi_driver for this device */ + .max_speed_hz = 3686400, /* Run SSP as fast a possbile */ + .bus_num = 2, /* Framework bus number */ + .chip_select = 1, /* Framework chip select */ + .controller_data = &cs8405a_chip_info, /* Master chip config */ + .irq = STREETRACER_APCI_IRQ, /* Slave device interrupt */ + }, + }; + + static void __init streetracer_init(void) + { + spi_register_board_info(streetracer_spi_board_info, + ARRAY_SIZE(streetracer_spi_board_info)); + } + + +DMA and PIO I/O Support +----------------------- +The pxa2xx_spi driver supports both DMA and interrupt driven PIO message +transfers. The driver defaults to PIO mode and DMA transfers must be enabled +by setting the "enable_dma" flag in the "pxa2xx_spi_controller" structure. +For the newer platforms, that are known to support DMA, the driver will enable +it automatically and try it first with a possible fallback to PIO. The DMA +mode supports both coherent and stream based DMA mappings. + +The following logic is used to determine the type of I/O to be used on +a per "spi_transfer" basis:: + + if !enable_dma then + always use PIO transfers + + if spi_message.len > 8191 then + print "rate limited" warning + use PIO transfers + + if spi_message.is_dma_mapped and rx_dma_buf != 0 and tx_dma_buf != 0 then + use coherent DMA mode + + if rx_buf and tx_buf are aligned on 8 byte boundary then + use streaming DMA mode + + otherwise + use PIO transfer + +THANKS TO +--------- +David Brownell and others for mentoring the development of this driver. -- cgit v1.2.3