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().
  ...

1 files changed, 542 insertions, 0 deletions

diff --git a/drivers/char/ipmi/ipmi_kcs_sm.c b/drivers/char/ipmi/ipmi_kcs_sm.c
new file mode 100644
index 000000000..ecfcb5030
--- /dev/null
+++ b/drivers/char/ipmi/ipmi_kcs_sm.c
@@ -0,0 +1,542 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * ipmi_kcs_sm.c
+ *
+ * State machine for handling IPMI KCS interfaces.
+ *
+ * Author: MontaVista Software, Inc.
+ *         Corey Minyard <minyard@mvista.com>
+ *         source@mvista.com
+ *
+ * Copyright 2002 MontaVista Software Inc.
+ */
+
+/*
+ * This state machine is taken from the state machine in the IPMI spec,
+ * pretty much verbatim.  If you have questions about the states, see
+ * that document.
+ */
+
+#define DEBUG /* So dev_dbg() is always available. */
+
+#include <linux/kernel.h> /* For printk. */
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/string.h>
+#include <linux/jiffies.h>
+#include <linux/ipmi_msgdefs.h>		/* for completion codes */
+#include "ipmi_si_sm.h"
+
+/* kcs_debug is a bit-field
+ *	KCS_DEBUG_ENABLE -	turned on for now
+ *	KCS_DEBUG_MSG    -	commands and their responses
+ *	KCS_DEBUG_STATES -	state machine
+ */
+#define KCS_DEBUG_STATES	4
+#define KCS_DEBUG_MSG		2
+#define	KCS_DEBUG_ENABLE	1
+
+static int kcs_debug;
+module_param(kcs_debug, int, 0644);
+MODULE_PARM_DESC(kcs_debug, "debug bitmask, 1=enable, 2=messages, 4=states");
+
+/* The states the KCS driver may be in. */
+enum kcs_states {
+	/* The KCS interface is currently doing nothing. */
+	KCS_IDLE,
+
+	/*
+	 * We are starting an operation.  The data is in the output
+	 * buffer, but nothing has been done to the interface yet.  This
+	 * was added to the state machine in the spec to wait for the
+	 * initial IBF.
+	 */
+	KCS_START_OP,
+
+	/* We have written a write cmd to the interface. */
+	KCS_WAIT_WRITE_START,
+
+	/* We are writing bytes to the interface. */
+	KCS_WAIT_WRITE,
+
+	/*
+	 * We have written the write end cmd to the interface, and
+	 * still need to write the last byte.
+	 */
+	KCS_WAIT_WRITE_END,
+
+	/* We are waiting to read data from the interface. */
+	KCS_WAIT_READ,
+
+	/*
+	 * State to transition to the error handler, this was added to
+	 * the state machine in the spec to be sure IBF was there.
+	 */
+	KCS_ERROR0,
+
+	/*
+	 * First stage error handler, wait for the interface to
+	 * respond.
+	 */
+	KCS_ERROR1,
+
+	/*
+	 * The abort cmd has been written, wait for the interface to
+	 * respond.
+	 */
+	KCS_ERROR2,
+
+	/*
+	 * We wrote some data to the interface, wait for it to switch
+	 * to read mode.
+	 */
+	KCS_ERROR3,
+
+	/* The hardware failed to follow the state machine. */
+	KCS_HOSED
+};
+
+#define MAX_KCS_READ_SIZE IPMI_MAX_MSG_LENGTH
+#define MAX_KCS_WRITE_SIZE IPMI_MAX_MSG_LENGTH
+
+/* Timeouts in microseconds. */
+#define IBF_RETRY_TIMEOUT (5*USEC_PER_SEC)
+#define OBF_RETRY_TIMEOUT (5*USEC_PER_SEC)
+#define MAX_ERROR_RETRIES 10
+#define ERROR0_OBF_WAIT_JIFFIES (2*HZ)
+
+struct si_sm_data {
+	enum kcs_states  state;
+	struct si_sm_io *io;
+	unsigned char    write_data[MAX_KCS_WRITE_SIZE];
+	int              write_pos;
+	int              write_count;
+	int              orig_write_count;
+	unsigned char    read_data[MAX_KCS_READ_SIZE];
+	int              read_pos;
+	int	         truncated;
+
+	unsigned int  error_retries;
+	long          ibf_timeout;
+	long          obf_timeout;
+	unsigned long  error0_timeout;
+};
+
+static unsigned int init_kcs_data_with_state(struct si_sm_data *kcs,
+				  struct si_sm_io *io, enum kcs_states state)
+{
+	kcs->state = state;
+	kcs->io = io;
+	kcs->write_pos = 0;
+	kcs->write_count = 0;
+	kcs->orig_write_count = 0;
+	kcs->read_pos = 0;
+	kcs->error_retries = 0;
+	kcs->truncated = 0;
+	kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
+	kcs->obf_timeout = OBF_RETRY_TIMEOUT;
+
+	/* Reserve 2 I/O bytes. */
+	return 2;
+}
+
+static unsigned int init_kcs_data(struct si_sm_data *kcs,
+				  struct si_sm_io *io)
+{
+	return init_kcs_data_with_state(kcs, io, KCS_IDLE);
+}
+
+static inline unsigned char read_status(struct si_sm_data *kcs)
+{
+	return kcs->io->inputb(kcs->io, 1);
+}
+
+static inline unsigned char read_data(struct si_sm_data *kcs)
+{
+	return kcs->io->inputb(kcs->io, 0);
+}
+
+static inline void write_cmd(struct si_sm_data *kcs, unsigned char data)
+{
+	kcs->io->outputb(kcs->io, 1, data);
+}
+
+static inline void write_data(struct si_sm_data *kcs, unsigned char data)
+{
+	kcs->io->outputb(kcs->io, 0, data);
+}
+
+/* Control codes. */
+#define KCS_GET_STATUS_ABORT	0x60
+#define KCS_WRITE_START		0x61
+#define KCS_WRITE_END		0x62
+#define KCS_READ_BYTE		0x68
+
+/* Status bits. */
+#define GET_STATUS_STATE(status) (((status) >> 6) & 0x03)
+#define KCS_IDLE_STATE	0
+#define KCS_READ_STATE	1
+#define KCS_WRITE_STATE	2
+#define KCS_ERROR_STATE	3
+#define GET_STATUS_ATN(status) ((status) & 0x04)
+#define GET_STATUS_IBF(status) ((status) & 0x02)
+#define GET_STATUS_OBF(status) ((status) & 0x01)
+
+
+static inline void write_next_byte(struct si_sm_data *kcs)
+{
+	write_data(kcs, kcs->write_data[kcs->write_pos]);
+	(kcs->write_pos)++;
+	(kcs->write_count)--;
+}
+
+static inline void start_error_recovery(struct si_sm_data *kcs, char *reason)
+{
+	(kcs->error_retries)++;
+	if (kcs->error_retries > MAX_ERROR_RETRIES) {
+		if (kcs_debug & KCS_DEBUG_ENABLE)
+			dev_dbg(kcs->io->dev, "ipmi_kcs_sm: kcs hosed: %s\n",
+				reason);
+		kcs->state = KCS_HOSED;
+	} else {
+		kcs->error0_timeout = jiffies + ERROR0_OBF_WAIT_JIFFIES;
+		kcs->state = KCS_ERROR0;
+	}
+}
+
+static inline void read_next_byte(struct si_sm_data *kcs)
+{
+	if (kcs->read_pos >= MAX_KCS_READ_SIZE) {
+		/* Throw the data away and mark it truncated. */
+		read_data(kcs);
+		kcs->truncated = 1;
+	} else {
+		kcs->read_data[kcs->read_pos] = read_data(kcs);
+		(kcs->read_pos)++;
+	}
+	write_data(kcs, KCS_READ_BYTE);
+}
+
+static inline int check_ibf(struct si_sm_data *kcs, unsigned char status,
+			    long time)
+{
+	if (GET_STATUS_IBF(status)) {
+		kcs->ibf_timeout -= time;
+		if (kcs->ibf_timeout < 0) {
+			start_error_recovery(kcs, "IBF not ready in time");
+			kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
+			return 1;
+		}
+		return 0;
+	}
+	kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
+	return 1;
+}
+
+static inline int check_obf(struct si_sm_data *kcs, unsigned char status,
+			    long time)
+{
+	if (!GET_STATUS_OBF(status)) {
+		kcs->obf_timeout -= time;
+		if (kcs->obf_timeout < 0) {
+			kcs->obf_timeout = OBF_RETRY_TIMEOUT;
+			start_error_recovery(kcs, "OBF not ready in time");
+			return 1;
+		}
+		return 0;
+	}
+	kcs->obf_timeout = OBF_RETRY_TIMEOUT;
+	return 1;
+}
+
+static void clear_obf(struct si_sm_data *kcs, unsigned char status)
+{
+	if (GET_STATUS_OBF(status))
+		read_data(kcs);
+}
+
+static void restart_kcs_transaction(struct si_sm_data *kcs)
+{
+	kcs->write_count = kcs->orig_write_count;
+	kcs->write_pos = 0;
+	kcs->read_pos = 0;
+	kcs->state = KCS_WAIT_WRITE_START;
+	kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
+	kcs->obf_timeout = OBF_RETRY_TIMEOUT;
+	write_cmd(kcs, KCS_WRITE_START);
+}
+
+static int start_kcs_transaction(struct si_sm_data *kcs, unsigned char *data,
+				 unsigned int size)
+{
+	unsigned int i;
+
+	if (size < 2)
+		return IPMI_REQ_LEN_INVALID_ERR;
+	if (size > MAX_KCS_WRITE_SIZE)
+		return IPMI_REQ_LEN_EXCEEDED_ERR;
+
+	if (kcs->state != KCS_IDLE) {
+		dev_warn(kcs->io->dev, "KCS in invalid state %d\n", kcs->state);
+		return IPMI_NOT_IN_MY_STATE_ERR;
+	}
+
+	if (kcs_debug & KCS_DEBUG_MSG) {
+		dev_dbg(kcs->io->dev, "%s -", __func__);
+		for (i = 0; i < size; i++)
+			pr_cont(" %02x", data[i]);
+		pr_cont("\n");
+	}
+	kcs->error_retries = 0;
+	memcpy(kcs->write_data, data, size);
+	kcs->write_count = size;
+	kcs->orig_write_count = size;
+	kcs->write_pos = 0;
+	kcs->read_pos = 0;
+	kcs->state = KCS_START_OP;
+	kcs->ibf_timeout = IBF_RETRY_TIMEOUT;
+	kcs->obf_timeout = OBF_RETRY_TIMEOUT;
+	return 0;
+}
+
+static int get_kcs_result(struct si_sm_data *kcs, unsigned char *data,
+			  unsigned int length)
+{
+	if (length < kcs->read_pos) {
+		kcs->read_pos = length;
+		kcs->truncated = 1;
+	}
+
+	memcpy(data, kcs->read_data, kcs->read_pos);
+
+	if ((length >= 3) && (kcs->read_pos < 3)) {
+		/* Guarantee that we return at least 3 bytes, with an
+		   error in the third byte if it is too short. */
+		data[2] = IPMI_ERR_UNSPECIFIED;
+		kcs->read_pos = 3;
+	}
+	if (kcs->truncated) {
+		/*
+		 * Report a truncated error.  We might overwrite
+		 * another error, but that's too bad, the user needs
+		 * to know it was truncated.
+		 */
+		data[2] = IPMI_ERR_MSG_TRUNCATED;
+		kcs->truncated = 0;
+	}
+
+	return kcs->read_pos;
+}
+
+/*
+ * This implements the state machine defined in the IPMI manual, see
+ * that for details on how this works.  Divide that flowchart into
+ * sections delimited by "Wait for IBF" and this will become clear.
+ */
+static enum si_sm_result kcs_event(struct si_sm_data *kcs, long time)
+{
+	unsigned char status;
+	unsigned char state;
+
+	status = read_status(kcs);
+
+	if (kcs_debug & KCS_DEBUG_STATES)
+		dev_dbg(kcs->io->dev,
+			"KCS: State = %d, %x\n", kcs->state, status);
+
+	/* All states wait for ibf, so just do it here. */
+	if (!check_ibf(kcs, status, time))
+		return SI_SM_CALL_WITH_DELAY;
+
+	/* Just about everything looks at the KCS state, so grab that, too. */
+	state = GET_STATUS_STATE(status);
+
+	switch (kcs->state) {
+	case KCS_IDLE:
+		/* If there's and interrupt source, turn it off. */
+		clear_obf(kcs, status);
+
+		if (GET_STATUS_ATN(status))
+			return SI_SM_ATTN;
+		else
+			return SI_SM_IDLE;
+
+	case KCS_START_OP:
+		if (state != KCS_IDLE_STATE) {
+			start_error_recovery(kcs,
+					     "State machine not idle at start");
+			break;
+		}
+
+		clear_obf(kcs, status);
+		write_cmd(kcs, KCS_WRITE_START);
+		kcs->state = KCS_WAIT_WRITE_START;
+		break;
+
+	case KCS_WAIT_WRITE_START:
+		if (state != KCS_WRITE_STATE) {
+			start_error_recovery(
+				kcs,
+				"Not in write state at write start");
+			break;
+		}
+		read_data(kcs);
+		if (kcs->write_count == 1) {
+			write_cmd(kcs, KCS_WRITE_END);
+			kcs->state = KCS_WAIT_WRITE_END;
+		} else {
+			write_next_byte(kcs);
+			kcs->state = KCS_WAIT_WRITE;
+		}
+		break;
+
+	case KCS_WAIT_WRITE:
+		if (state != KCS_WRITE_STATE) {
+			start_error_recovery(kcs,
+					     "Not in write state for write");
+			break;
+		}
+		clear_obf(kcs, status);
+		if (kcs->write_count == 1) {
+			write_cmd(kcs, KCS_WRITE_END);
+			kcs->state = KCS_WAIT_WRITE_END;
+		} else {
+			write_next_byte(kcs);
+		}
+		break;
+
+	case KCS_WAIT_WRITE_END:
+		if (state != KCS_WRITE_STATE) {
+			start_error_recovery(kcs,
+					     "Not in write state"
+					     " for write end");
+			break;
+		}
+		clear_obf(kcs, status);
+		write_next_byte(kcs);
+		kcs->state = KCS_WAIT_READ;
+		break;
+
+	case KCS_WAIT_READ:
+		if ((state != KCS_READ_STATE) && (state != KCS_IDLE_STATE)) {
+			start_error_recovery(
+				kcs,
+				"Not in read or idle in read state");
+			break;
+		}
+
+		if (state == KCS_READ_STATE) {
+			if (!check_obf(kcs, status, time))
+				return SI_SM_CALL_WITH_DELAY;
+			read_next_byte(kcs);
+		} else {
+			/*
+			 * We don't implement this exactly like the state
+			 * machine in the spec.  Some broken hardware
+			 * does not write the final dummy byte to the
+			 * read register.  Thus obf will never go high
+			 * here.  We just go straight to idle, and we
+			 * handle clearing out obf in idle state if it
+			 * happens to come in.
+			 */
+			clear_obf(kcs, status);
+			kcs->orig_write_count = 0;
+			kcs->state = KCS_IDLE;
+			return SI_SM_TRANSACTION_COMPLETE;
+		}
+		break;
+
+	case KCS_ERROR0:
+		clear_obf(kcs, status);
+		status = read_status(kcs);
+		if (GET_STATUS_OBF(status))
+			/* controller isn't responding */
+			if (time_before(jiffies, kcs->error0_timeout))
+				return SI_SM_CALL_WITH_TICK_DELAY;
+		write_cmd(kcs, KCS_GET_STATUS_ABORT);
+		kcs->state = KCS_ERROR1;
+		break;
+
+	case KCS_ERROR1:
+		clear_obf(kcs, status);
+		write_data(kcs, 0);
+		kcs->state = KCS_ERROR2;
+		break;
+
+	case KCS_ERROR2:
+		if (state != KCS_READ_STATE) {
+			start_error_recovery(kcs,
+					     "Not in read state for error2");
+			break;
+		}
+		if (!check_obf(kcs, status, time))
+			return SI_SM_CALL_WITH_DELAY;
+
+		clear_obf(kcs, status);
+		write_data(kcs, KCS_READ_BYTE);
+		kcs->state = KCS_ERROR3;
+		break;
+
+	case KCS_ERROR3:
+		if (state != KCS_IDLE_STATE) {
+			start_error_recovery(kcs,
+					     "Not in idle state for error3");
+			break;
+		}
+
+		if (!check_obf(kcs, status, time))
+			return SI_SM_CALL_WITH_DELAY;
+
+		clear_obf(kcs, status);
+		if (kcs->orig_write_count) {
+			restart_kcs_transaction(kcs);
+		} else {
+			kcs->state = KCS_IDLE;
+			return SI_SM_TRANSACTION_COMPLETE;
+		}
+		break;
+
+	case KCS_HOSED:
+		break;
+	}
+
+	if (kcs->state == KCS_HOSED) {
+		init_kcs_data_with_state(kcs, kcs->io, KCS_ERROR0);
+		return SI_SM_HOSED;
+	}
+
+	return SI_SM_CALL_WITHOUT_DELAY;
+}
+
+static int kcs_size(void)
+{
+	return sizeof(struct si_sm_data);
+}
+
+static int kcs_detect(struct si_sm_data *kcs)
+{
+	/*
+	 * It's impossible for the KCS status register to be all 1's,
+	 * (assuming a properly functioning, self-initialized BMC)
+	 * but that's what you get from reading a bogus address, so we
+	 * test that first.
+	 */
+	if (read_status(kcs) == 0xff)
+		return 1;
+
+	return 0;
+}
+
+static void kcs_cleanup(struct si_sm_data *kcs)
+{
+}
+
+const struct si_sm_handlers kcs_smi_handlers = {
+	.init_data         = init_kcs_data,
+	.start_transaction = start_kcs_transaction,
+	.get_result        = get_kcs_result,
+	.event             = kcs_event,
+	.detect            = kcs_detect,
+	.cleanup           = kcs_cleanup,
+	.size              = kcs_size,
+};