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, 1225 insertions, 0 deletions

diff --git a/drivers/tty/hvc/hvsi.c b/drivers/tty/hvc/hvsi.c
new file mode 100644
index 000000000..a200d01ec
--- /dev/null
+++ b/drivers/tty/hvc/hvsi.c
@@ -0,0 +1,1225 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2004 Hollis Blanchard <hollisb@us.ibm.com>, IBM
+ */
+
+/* Host Virtual Serial Interface (HVSI) is a protocol between the hosted OS
+ * and the service processor on IBM pSeries servers. On these servers, there
+ * are no serial ports under the OS's control, and sometimes there is no other
+ * console available either. However, the service processor has two standard
+ * serial ports, so this over-complicated protocol allows the OS to control
+ * those ports by proxy.
+ *
+ * Besides data, the procotol supports the reading/writing of the serial
+ * port's DTR line, and the reading of the CD line. This is to allow the OS to
+ * control a modem attached to the service processor's serial port. Note that
+ * the OS cannot change the speed of the port through this protocol.
+ */
+
+#undef DEBUG
+
+#include <linux/console.h>
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/major.h>
+#include <linux/kernel.h>
+#include <linux/of_irq.h>
+#include <linux/spinlock.h>
+#include <linux/sysrq.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <asm/hvcall.h>
+#include <asm/hvconsole.h>
+#include <linux/uaccess.h>
+#include <asm/vio.h>
+#include <asm/param.h>
+#include <asm/hvsi.h>
+
+#define HVSI_MAJOR	229
+#define HVSI_MINOR	128
+#define MAX_NR_HVSI_CONSOLES 4
+
+#define HVSI_TIMEOUT (5*HZ)
+#define HVSI_VERSION 1
+#define HVSI_MAX_PACKET 256
+#define HVSI_MAX_READ 16
+#define HVSI_MAX_OUTGOING_DATA 12
+#define N_OUTBUF 12
+
+/*
+ * we pass data via two 8-byte registers, so we would like our char arrays
+ * properly aligned for those loads.
+ */
+#define __ALIGNED__	__attribute__((__aligned__(sizeof(long))))
+
+struct hvsi_struct {
+	struct tty_port port;
+	struct delayed_work writer;
+	struct work_struct handshaker;
+	wait_queue_head_t emptyq; /* woken when outbuf is emptied */
+	wait_queue_head_t stateq; /* woken when HVSI state changes */
+	spinlock_t lock;
+	int index;
+	uint8_t throttle_buf[128];
+	uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
+	/* inbuf is for packet reassembly. leave a little room for leftovers. */
+	uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
+	uint8_t *inbuf_end;
+	int n_throttle;
+	int n_outbuf;
+	uint32_t vtermno;
+	uint32_t virq;
+	atomic_t seqno; /* HVSI packet sequence number */
+	uint16_t mctrl;
+	uint8_t state;  /* HVSI protocol state */
+	uint8_t flags;
+#ifdef CONFIG_MAGIC_SYSRQ
+	uint8_t sysrq;
+#endif /* CONFIG_MAGIC_SYSRQ */
+};
+static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
+
+static struct tty_driver *hvsi_driver;
+static int hvsi_count;
+static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
+
+enum HVSI_PROTOCOL_STATE {
+	HVSI_CLOSED,
+	HVSI_WAIT_FOR_VER_RESPONSE,
+	HVSI_WAIT_FOR_VER_QUERY,
+	HVSI_OPEN,
+	HVSI_WAIT_FOR_MCTRL_RESPONSE,
+	HVSI_FSP_DIED,
+};
+#define HVSI_CONSOLE 0x1
+
+static inline int is_console(struct hvsi_struct *hp)
+{
+	return hp->flags & HVSI_CONSOLE;
+}
+
+static inline int is_open(struct hvsi_struct *hp)
+{
+	/* if we're waiting for an mctrl then we're already open */
+	return (hp->state == HVSI_OPEN)
+			|| (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
+}
+
+static inline void print_state(struct hvsi_struct *hp)
+{
+#ifdef DEBUG
+	static const char *state_names[] = {
+		"HVSI_CLOSED",
+		"HVSI_WAIT_FOR_VER_RESPONSE",
+		"HVSI_WAIT_FOR_VER_QUERY",
+		"HVSI_OPEN",
+		"HVSI_WAIT_FOR_MCTRL_RESPONSE",
+		"HVSI_FSP_DIED",
+	};
+	const char *name = (hp->state < ARRAY_SIZE(state_names))
+		? state_names[hp->state] : "UNKNOWN";
+
+	pr_debug("hvsi%i: state = %s\n", hp->index, name);
+#endif /* DEBUG */
+}
+
+static inline void __set_state(struct hvsi_struct *hp, int state)
+{
+	hp->state = state;
+	print_state(hp);
+	wake_up_all(&hp->stateq);
+}
+
+static inline void set_state(struct hvsi_struct *hp, int state)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&hp->lock, flags);
+	__set_state(hp, state);
+	spin_unlock_irqrestore(&hp->lock, flags);
+}
+
+static inline int len_packet(const uint8_t *packet)
+{
+	return (int)((struct hvsi_header *)packet)->len;
+}
+
+static inline int is_header(const uint8_t *packet)
+{
+	struct hvsi_header *header = (struct hvsi_header *)packet;
+	return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
+}
+
+static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
+{
+	if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
+		return 0; /* don't even have the packet header */
+
+	if (hp->inbuf_end < (packet + len_packet(packet)))
+		return 0; /* don't have the rest of the packet */
+
+	return 1;
+}
+
+/* shift remaining bytes in packetbuf down */
+static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
+{
+	int remaining = (int)(hp->inbuf_end - read_to);
+
+	pr_debug("%s: %i chars remain\n", __func__, remaining);
+
+	if (read_to != hp->inbuf)
+		memmove(hp->inbuf, read_to, remaining);
+
+	hp->inbuf_end = hp->inbuf + remaining;
+}
+
+#ifdef DEBUG
+#define dbg_dump_packet(packet) dump_packet(packet)
+#define dbg_dump_hex(data, len) dump_hex(data, len)
+#else
+#define dbg_dump_packet(packet) do { } while (0)
+#define dbg_dump_hex(data, len) do { } while (0)
+#endif
+
+static void dump_hex(const uint8_t *data, int len)
+{
+	int i;
+
+	printk("    ");
+	for (i=0; i < len; i++)
+		printk("%.2x", data[i]);
+
+	printk("\n    ");
+	for (i=0; i < len; i++) {
+		if (isprint(data[i]))
+			printk("%c", data[i]);
+		else
+			printk(".");
+	}
+	printk("\n");
+}
+
+static void dump_packet(uint8_t *packet)
+{
+	struct hvsi_header *header = (struct hvsi_header *)packet;
+
+	printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
+			header->seqno);
+
+	dump_hex(packet, header->len);
+}
+
+static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
+{
+	unsigned long got;
+
+	got = hvc_get_chars(hp->vtermno, buf, count);
+
+	return got;
+}
+
+static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
+	struct tty_struct *tty, struct hvsi_struct **to_handshake)
+{
+	struct hvsi_control *header = (struct hvsi_control *)packet;
+
+	switch (be16_to_cpu(header->verb)) {
+		case VSV_MODEM_CTL_UPDATE:
+			if ((be32_to_cpu(header->word) & HVSI_TSCD) == 0) {
+				/* CD went away; no more connection */
+				pr_debug("hvsi%i: CD dropped\n", hp->index);
+				hp->mctrl &= TIOCM_CD;
+				if (tty && !C_CLOCAL(tty))
+					tty_hangup(tty);
+			}
+			break;
+		case VSV_CLOSE_PROTOCOL:
+			pr_debug("hvsi%i: service processor came back\n", hp->index);
+			if (hp->state != HVSI_CLOSED) {
+				*to_handshake = hp;
+			}
+			break;
+		default:
+			printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
+				hp->index);
+			dump_packet(packet);
+			break;
+	}
+}
+
+static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
+{
+	struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
+	uint32_t mctrl_word;
+
+	switch (hp->state) {
+		case HVSI_WAIT_FOR_VER_RESPONSE:
+			__set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
+			break;
+		case HVSI_WAIT_FOR_MCTRL_RESPONSE:
+			hp->mctrl = 0;
+			mctrl_word = be32_to_cpu(resp->u.mctrl_word);
+			if (mctrl_word & HVSI_TSDTR)
+				hp->mctrl |= TIOCM_DTR;
+			if (mctrl_word & HVSI_TSCD)
+				hp->mctrl |= TIOCM_CD;
+			__set_state(hp, HVSI_OPEN);
+			break;
+		default:
+			printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
+			dump_packet(packet);
+			break;
+	}
+}
+
+/* respond to service processor's version query */
+static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
+{
+	struct hvsi_query_response packet __ALIGNED__;
+	int wrote;
+
+	packet.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER;
+	packet.hdr.len = sizeof(struct hvsi_query_response);
+	packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
+	packet.verb = cpu_to_be16(VSV_SEND_VERSION_NUMBER);
+	packet.u.version = HVSI_VERSION;
+	packet.query_seqno = cpu_to_be16(query_seqno+1);
+
+	pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
+	dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
+
+	wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
+	if (wrote != packet.hdr.len) {
+		printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
+			hp->index);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
+{
+	struct hvsi_query *query = (struct hvsi_query *)packet;
+
+	switch (hp->state) {
+		case HVSI_WAIT_FOR_VER_QUERY:
+			hvsi_version_respond(hp, be16_to_cpu(query->hdr.seqno));
+			__set_state(hp, HVSI_OPEN);
+			break;
+		default:
+			printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
+			dump_packet(packet);
+			break;
+	}
+}
+
+static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
+{
+	int i;
+
+	for (i=0; i < len; i++) {
+		char c = buf[i];
+#ifdef CONFIG_MAGIC_SYSRQ
+		if (c == '\0') {
+			hp->sysrq = 1;
+			continue;
+		} else if (hp->sysrq) {
+			handle_sysrq(c);
+			hp->sysrq = 0;
+			continue;
+		}
+#endif /* CONFIG_MAGIC_SYSRQ */
+		tty_insert_flip_char(&hp->port, c, 0);
+	}
+}
+
+/*
+ * We could get 252 bytes of data at once here. But the tty layer only
+ * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
+ * it. Accordingly we won't send more than 128 bytes at a time to the flip
+ * buffer, which will give the tty buffer a chance to throttle us. Should the
+ * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
+ * revisited.
+ */
+#define TTY_THRESHOLD_THROTTLE 128
+static bool hvsi_recv_data(struct hvsi_struct *hp, const uint8_t *packet)
+{
+	const struct hvsi_header *header = (const struct hvsi_header *)packet;
+	const uint8_t *data = packet + sizeof(struct hvsi_header);
+	int datalen = header->len - sizeof(struct hvsi_header);
+	int overflow = datalen - TTY_THRESHOLD_THROTTLE;
+
+	pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
+
+	if (datalen == 0)
+		return false;
+
+	if (overflow > 0) {
+		pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__);
+		datalen = TTY_THRESHOLD_THROTTLE;
+	}
+
+	hvsi_insert_chars(hp, data, datalen);
+
+	if (overflow > 0) {
+		/*
+		 * we still have more data to deliver, so we need to save off the
+		 * overflow and send it later
+		 */
+		pr_debug("%s: deferring overflow\n", __func__);
+		memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
+		hp->n_throttle = overflow;
+	}
+
+	return true;
+}
+
+/*
+ * Returns true/false indicating data successfully read from hypervisor.
+ * Used both to get packets for tty connections and to advance the state
+ * machine during console handshaking (in which case tty = NULL and we ignore
+ * incoming data).
+ */
+static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct *tty,
+		struct hvsi_struct **handshake)
+{
+	uint8_t *packet = hp->inbuf;
+	int chunklen;
+	bool flip = false;
+
+	*handshake = NULL;
+
+	chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
+	if (chunklen == 0) {
+		pr_debug("%s: 0-length read\n", __func__);
+		return 0;
+	}
+
+	pr_debug("%s: got %i bytes\n", __func__, chunklen);
+	dbg_dump_hex(hp->inbuf_end, chunklen);
+
+	hp->inbuf_end += chunklen;
+
+	/* handle all completed packets */
+	while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
+		struct hvsi_header *header = (struct hvsi_header *)packet;
+
+		if (!is_header(packet)) {
+			printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
+			/* skip bytes until we find a header or run out of data */
+			while ((packet < hp->inbuf_end) && (!is_header(packet)))
+				packet++;
+			continue;
+		}
+
+		pr_debug("%s: handling %i-byte packet\n", __func__,
+				len_packet(packet));
+		dbg_dump_packet(packet);
+
+		switch (header->type) {
+			case VS_DATA_PACKET_HEADER:
+				if (!is_open(hp))
+					break;
+				flip = hvsi_recv_data(hp, packet);
+				break;
+			case VS_CONTROL_PACKET_HEADER:
+				hvsi_recv_control(hp, packet, tty, handshake);
+				break;
+			case VS_QUERY_RESPONSE_PACKET_HEADER:
+				hvsi_recv_response(hp, packet);
+				break;
+			case VS_QUERY_PACKET_HEADER:
+				hvsi_recv_query(hp, packet);
+				break;
+			default:
+				printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
+						hp->index, header->type);
+				dump_packet(packet);
+				break;
+		}
+
+		packet += len_packet(packet);
+
+		if (*handshake) {
+			pr_debug("%s: handshake\n", __func__);
+			break;
+		}
+	}
+
+	compact_inbuf(hp, packet);
+
+	if (flip)
+		tty_flip_buffer_push(&hp->port);
+
+	return 1;
+}
+
+static void hvsi_send_overflow(struct hvsi_struct *hp)
+{
+	pr_debug("%s: delivering %i bytes overflow\n", __func__,
+			hp->n_throttle);
+
+	hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
+	hp->n_throttle = 0;
+}
+
+/*
+ * must get all pending data because we only get an irq on empty->non-empty
+ * transition
+ */
+static irqreturn_t hvsi_interrupt(int irq, void *arg)
+{
+	struct hvsi_struct *hp = (struct hvsi_struct *)arg;
+	struct hvsi_struct *handshake;
+	struct tty_struct *tty;
+	unsigned long flags;
+	int again = 1;
+
+	pr_debug("%s\n", __func__);
+
+	tty = tty_port_tty_get(&hp->port);
+
+	while (again) {
+		spin_lock_irqsave(&hp->lock, flags);
+		again = hvsi_load_chunk(hp, tty, &handshake);
+		spin_unlock_irqrestore(&hp->lock, flags);
+
+		if (handshake) {
+			pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
+			schedule_work(&handshake->handshaker);
+		}
+	}
+
+	spin_lock_irqsave(&hp->lock, flags);
+	if (tty && hp->n_throttle && !tty_throttled(tty)) {
+		/* we weren't hung up and we weren't throttled, so we can
+		 * deliver the rest now */
+		hvsi_send_overflow(hp);
+		tty_flip_buffer_push(&hp->port);
+	}
+	spin_unlock_irqrestore(&hp->lock, flags);
+
+	tty_kref_put(tty);
+
+	return IRQ_HANDLED;
+}
+
+/* for boot console, before the irq handler is running */
+static int __init poll_for_state(struct hvsi_struct *hp, int state)
+{
+	unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
+
+	for (;;) {
+		hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
+
+		if (hp->state == state)
+			return 0;
+
+		mdelay(5);
+		if (time_after(jiffies, end_jiffies))
+			return -EIO;
+	}
+}
+
+/* wait for irq handler to change our state */
+static int wait_for_state(struct hvsi_struct *hp, int state)
+{
+	int ret = 0;
+
+	if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
+		ret = -EIO;
+
+	return ret;
+}
+
+static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
+{
+	struct hvsi_query packet __ALIGNED__;
+	int wrote;
+
+	packet.hdr.type = VS_QUERY_PACKET_HEADER;
+	packet.hdr.len = sizeof(struct hvsi_query);
+	packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
+	packet.verb = cpu_to_be16(verb);
+
+	pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
+	dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
+
+	wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
+	if (wrote != packet.hdr.len) {
+		printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
+			wrote);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int hvsi_get_mctrl(struct hvsi_struct *hp)
+{
+	int ret;
+
+	set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
+	hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
+
+	ret = hvsi_wait(hp, HVSI_OPEN);
+	if (ret < 0) {
+		printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
+		set_state(hp, HVSI_OPEN);
+		return ret;
+	}
+
+	pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
+
+	return 0;
+}
+
+/* note that we can only set DTR */
+static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
+{
+	struct hvsi_control packet __ALIGNED__;
+	int wrote;
+
+	packet.hdr.type = VS_CONTROL_PACKET_HEADER;
+	packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
+	packet.hdr.len = sizeof(struct hvsi_control);
+	packet.verb = cpu_to_be16(VSV_SET_MODEM_CTL);
+	packet.mask = cpu_to_be32(HVSI_TSDTR);
+
+	if (mctrl & TIOCM_DTR)
+		packet.word = cpu_to_be32(HVSI_TSDTR);
+
+	pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
+	dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
+
+	wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
+	if (wrote != packet.hdr.len) {
+		printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static void hvsi_drain_input(struct hvsi_struct *hp)
+{
+	uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
+	unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
+
+	while (time_before(end_jiffies, jiffies))
+		if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
+			break;
+}
+
+static int hvsi_handshake(struct hvsi_struct *hp)
+{
+	int ret;
+
+	/*
+	 * We could have a CLOSE or other data waiting for us before we even try
+	 * to open; try to throw it all away so we don't get confused. (CLOSE
+	 * is the first message sent up the pipe when the FSP comes online. We
+	 * need to distinguish between "it came up a while ago and we're the first
+	 * user" and "it was just reset before it saw our handshake packet".)
+	 */
+	hvsi_drain_input(hp);
+
+	set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
+	ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
+	if (ret < 0) {
+		printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
+		return ret;
+	}
+
+	ret = hvsi_wait(hp, HVSI_OPEN);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static void hvsi_handshaker(struct work_struct *work)
+{
+	struct hvsi_struct *hp =
+		container_of(work, struct hvsi_struct, handshaker);
+
+	if (hvsi_handshake(hp) >= 0)
+		return;
+
+	printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
+	if (is_console(hp)) {
+		/*
+		 * ttys will re-attempt the handshake via hvsi_open, but
+		 * the console will not.
+		 */
+		printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
+	}
+}
+
+static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
+{
+	struct hvsi_data packet __ALIGNED__;
+	int ret;
+
+	BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
+
+	packet.hdr.type = VS_DATA_PACKET_HEADER;
+	packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
+	packet.hdr.len = count + sizeof(struct hvsi_header);
+	memcpy(&packet.data, buf, count);
+
+	ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
+	if (ret == packet.hdr.len) {
+		/* return the number of chars written, not the packet length */
+		return count;
+	}
+	return ret; /* return any errors */
+}
+
+static void hvsi_close_protocol(struct hvsi_struct *hp)
+{
+	struct hvsi_control packet __ALIGNED__;
+
+	packet.hdr.type = VS_CONTROL_PACKET_HEADER;
+	packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
+	packet.hdr.len = 6;
+	packet.verb = cpu_to_be16(VSV_CLOSE_PROTOCOL);
+
+	pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
+	dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
+
+	hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
+}
+
+static int hvsi_open(struct tty_struct *tty, struct file *filp)
+{
+	struct hvsi_struct *hp;
+	unsigned long flags;
+	int ret;
+
+	pr_debug("%s\n", __func__);
+
+	hp = &hvsi_ports[tty->index];
+
+	tty->driver_data = hp;
+
+	mb();
+	if (hp->state == HVSI_FSP_DIED)
+		return -EIO;
+
+	tty_port_tty_set(&hp->port, tty);
+	spin_lock_irqsave(&hp->lock, flags);
+	hp->port.count++;
+	atomic_set(&hp->seqno, 0);
+	h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
+	spin_unlock_irqrestore(&hp->lock, flags);
+
+	if (is_console(hp))
+		return 0; /* this has already been handshaked as the console */
+
+	ret = hvsi_handshake(hp);
+	if (ret < 0) {
+		printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
+		return ret;
+	}
+
+	ret = hvsi_get_mctrl(hp);
+	if (ret < 0) {
+		printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
+		return ret;
+	}
+
+	ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
+	if (ret < 0) {
+		printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
+		return ret;
+	}
+
+	return 0;
+}
+
+/* wait for hvsi_write_worker to empty hp->outbuf */
+static void hvsi_flush_output(struct hvsi_struct *hp)
+{
+	wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
+
+	/* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
+	cancel_delayed_work_sync(&hp->writer);
+	flush_work(&hp->handshaker);
+
+	/*
+	 * it's also possible that our timeout expired and hvsi_write_worker
+	 * didn't manage to push outbuf. poof.
+	 */
+	hp->n_outbuf = 0;
+}
+
+static void hvsi_close(struct tty_struct *tty, struct file *filp)
+{
+	struct hvsi_struct *hp = tty->driver_data;
+	unsigned long flags;
+
+	pr_debug("%s\n", __func__);
+
+	if (tty_hung_up_p(filp))
+		return;
+
+	spin_lock_irqsave(&hp->lock, flags);
+
+	if (--hp->port.count == 0) {
+		tty_port_tty_set(&hp->port, NULL);
+		hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
+
+		/* only close down connection if it is not the console */
+		if (!is_console(hp)) {
+			h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
+			__set_state(hp, HVSI_CLOSED);
+			/*
+			 * any data delivered to the tty layer after this will be
+			 * discarded (except for XON/XOFF)
+			 */
+			tty->closing = 1;
+
+			spin_unlock_irqrestore(&hp->lock, flags);
+
+			/* let any existing irq handlers finish. no more will start. */
+			synchronize_irq(hp->virq);
+
+			/* hvsi_write_worker will re-schedule until outbuf is empty. */
+			hvsi_flush_output(hp);
+
+			/* tell FSP to stop sending data */
+			hvsi_close_protocol(hp);
+
+			/*
+			 * drain anything FSP is still in the middle of sending, and let
+			 * hvsi_handshake drain the rest on the next open.
+			 */
+			hvsi_drain_input(hp);
+
+			spin_lock_irqsave(&hp->lock, flags);
+		}
+	} else if (hp->port.count < 0)
+		printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
+		       hp - hvsi_ports, hp->port.count);
+
+	spin_unlock_irqrestore(&hp->lock, flags);
+}
+
+static void hvsi_hangup(struct tty_struct *tty)
+{
+	struct hvsi_struct *hp = tty->driver_data;
+	unsigned long flags;
+
+	pr_debug("%s\n", __func__);
+
+	tty_port_tty_set(&hp->port, NULL);
+
+	spin_lock_irqsave(&hp->lock, flags);
+	hp->port.count = 0;
+	hp->n_outbuf = 0;
+	spin_unlock_irqrestore(&hp->lock, flags);
+}
+
+/* called with hp->lock held */
+static void hvsi_push(struct hvsi_struct *hp)
+{
+	int n;
+
+	if (hp->n_outbuf <= 0)
+		return;
+
+	n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
+	if (n > 0) {
+		/* success */
+		pr_debug("%s: wrote %i chars\n", __func__, n);
+		hp->n_outbuf = 0;
+	} else if (n == -EIO) {
+		__set_state(hp, HVSI_FSP_DIED);
+		printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
+	}
+}
+
+/* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
+static void hvsi_write_worker(struct work_struct *work)
+{
+	struct hvsi_struct *hp =
+		container_of(work, struct hvsi_struct, writer.work);
+	unsigned long flags;
+#ifdef DEBUG
+	static long start_j = 0;
+
+	if (start_j == 0)
+		start_j = jiffies;
+#endif /* DEBUG */
+
+	spin_lock_irqsave(&hp->lock, flags);
+
+	pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
+
+	if (!is_open(hp)) {
+		/*
+		 * We could have a non-open connection if the service processor died
+		 * while we were busily scheduling ourselves. In that case, it could
+		 * be minutes before the service processor comes back, so only try
+		 * again once a second.
+		 */
+		schedule_delayed_work(&hp->writer, HZ);
+		goto out;
+	}
+
+	hvsi_push(hp);
+	if (hp->n_outbuf > 0)
+		schedule_delayed_work(&hp->writer, 10);
+	else {
+#ifdef DEBUG
+		pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
+				jiffies - start_j);
+		start_j = 0;
+#endif /* DEBUG */
+		wake_up_all(&hp->emptyq);
+		tty_port_tty_wakeup(&hp->port);
+	}
+
+out:
+	spin_unlock_irqrestore(&hp->lock, flags);
+}
+
+static unsigned int hvsi_write_room(struct tty_struct *tty)
+{
+	struct hvsi_struct *hp = tty->driver_data;
+
+	return N_OUTBUF - hp->n_outbuf;
+}
+
+static unsigned int hvsi_chars_in_buffer(struct tty_struct *tty)
+{
+	struct hvsi_struct *hp = tty->driver_data;
+
+	return hp->n_outbuf;
+}
+
+static int hvsi_write(struct tty_struct *tty,
+		     const unsigned char *buf, int count)
+{
+	struct hvsi_struct *hp = tty->driver_data;
+	const char *source = buf;
+	unsigned long flags;
+	int total = 0;
+	int origcount = count;
+
+	spin_lock_irqsave(&hp->lock, flags);
+
+	pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
+
+	if (!is_open(hp)) {
+		/* we're either closing or not yet open; don't accept data */
+		pr_debug("%s: not open\n", __func__);
+		goto out;
+	}
+
+	/*
+	 * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
+	 * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
+	 * will see there is no room in outbuf and return.
+	 */
+	while ((count > 0) && (hvsi_write_room(tty) > 0)) {
+		int chunksize = min_t(int, count, hvsi_write_room(tty));
+
+		BUG_ON(hp->n_outbuf < 0);
+		memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
+		hp->n_outbuf += chunksize;
+
+		total += chunksize;
+		source += chunksize;
+		count -= chunksize;
+		hvsi_push(hp);
+	}
+
+	if (hp->n_outbuf > 0) {
+		/*
+		 * we weren't able to write it all to the hypervisor.
+		 * schedule another push attempt.
+		 */
+		schedule_delayed_work(&hp->writer, 10);
+	}
+
+out:
+	spin_unlock_irqrestore(&hp->lock, flags);
+
+	if (total != origcount)
+		pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount,
+			total);
+
+	return total;
+}
+
+/*
+ * I have never seen throttle or unthrottle called, so this little throttle
+ * buffering scheme may or may not work.
+ */
+static void hvsi_throttle(struct tty_struct *tty)
+{
+	struct hvsi_struct *hp = tty->driver_data;
+
+	pr_debug("%s\n", __func__);
+
+	h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
+}
+
+static void hvsi_unthrottle(struct tty_struct *tty)
+{
+	struct hvsi_struct *hp = tty->driver_data;
+	unsigned long flags;
+
+	pr_debug("%s\n", __func__);
+
+	spin_lock_irqsave(&hp->lock, flags);
+	if (hp->n_throttle) {
+		hvsi_send_overflow(hp);
+		tty_flip_buffer_push(&hp->port);
+	}
+	spin_unlock_irqrestore(&hp->lock, flags);
+
+
+	h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
+}
+
+static int hvsi_tiocmget(struct tty_struct *tty)
+{
+	struct hvsi_struct *hp = tty->driver_data;
+
+	hvsi_get_mctrl(hp);
+	return hp->mctrl;
+}
+
+static int hvsi_tiocmset(struct tty_struct *tty,
+				unsigned int set, unsigned int clear)
+{
+	struct hvsi_struct *hp = tty->driver_data;
+	unsigned long flags;
+	uint16_t new_mctrl;
+
+	/* we can only alter DTR */
+	clear &= TIOCM_DTR;
+	set &= TIOCM_DTR;
+
+	spin_lock_irqsave(&hp->lock, flags);
+
+	new_mctrl = (hp->mctrl & ~clear) | set;
+
+	if (hp->mctrl != new_mctrl) {
+		hvsi_set_mctrl(hp, new_mctrl);
+		hp->mctrl = new_mctrl;
+	}
+	spin_unlock_irqrestore(&hp->lock, flags);
+
+	return 0;
+}
+
+
+static const struct tty_operations hvsi_ops = {
+	.open = hvsi_open,
+	.close = hvsi_close,
+	.write = hvsi_write,
+	.hangup = hvsi_hangup,
+	.write_room = hvsi_write_room,
+	.chars_in_buffer = hvsi_chars_in_buffer,
+	.throttle = hvsi_throttle,
+	.unthrottle = hvsi_unthrottle,
+	.tiocmget = hvsi_tiocmget,
+	.tiocmset = hvsi_tiocmset,
+};
+
+static int __init hvsi_init(void)
+{
+	struct tty_driver *driver;
+	int i, ret;
+
+	driver = tty_alloc_driver(hvsi_count, TTY_DRIVER_REAL_RAW);
+	if (IS_ERR(driver))
+		return PTR_ERR(driver);
+
+	driver->driver_name = "hvsi";
+	driver->name = "hvsi";
+	driver->major = HVSI_MAJOR;
+	driver->minor_start = HVSI_MINOR;
+	driver->type = TTY_DRIVER_TYPE_SYSTEM;
+	driver->init_termios = tty_std_termios;
+	driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
+	driver->init_termios.c_ispeed = 9600;
+	driver->init_termios.c_ospeed = 9600;
+	tty_set_operations(driver, &hvsi_ops);
+
+	for (i=0; i < hvsi_count; i++) {
+		struct hvsi_struct *hp = &hvsi_ports[i];
+		int ret = 1;
+
+		tty_port_link_device(&hp->port, driver, i);
+
+		ret = request_irq(hp->virq, hvsi_interrupt, 0, "hvsi", hp);
+		if (ret)
+			printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
+				hp->virq, ret);
+	}
+	hvsi_wait = wait_for_state; /* irqs active now */
+
+	ret = tty_register_driver(driver);
+	if (ret) {
+		pr_err("Couldn't register hvsi console driver\n");
+		goto err_free_irq;
+	}
+
+	hvsi_driver = driver;
+
+	printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
+
+	return 0;
+err_free_irq:
+	hvsi_wait = poll_for_state;
+	for (i = 0; i < hvsi_count; i++) {
+		struct hvsi_struct *hp = &hvsi_ports[i];
+
+		free_irq(hp->virq, hp);
+	}
+	tty_driver_kref_put(driver);
+
+	return ret;
+}
+device_initcall(hvsi_init);
+
+/***** console (not tty) code: *****/
+
+static void hvsi_console_print(struct console *console, const char *buf,
+		unsigned int count)
+{
+	struct hvsi_struct *hp = &hvsi_ports[console->index];
+	char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
+	unsigned int i = 0, n = 0;
+	int ret, donecr = 0;
+
+	mb();
+	if (!is_open(hp))
+		return;
+
+	/*
+	 * ugh, we have to translate LF -> CRLF ourselves, in place.
+	 * copied from hvc_console.c:
+	 */
+	while (count > 0 || i > 0) {
+		if (count > 0 && i < sizeof(c)) {
+			if (buf[n] == '\n' && !donecr) {
+				c[i++] = '\r';
+				donecr = 1;
+			} else {
+				c[i++] = buf[n++];
+				donecr = 0;
+				--count;
+			}
+		} else {
+			ret = hvsi_put_chars(hp, c, i);
+			if (ret < 0)
+				i = 0;
+			i -= ret;
+		}
+	}
+}
+
+static struct tty_driver *hvsi_console_device(struct console *console,
+	int *index)
+{
+	*index = console->index;
+	return hvsi_driver;
+}
+
+static int __init hvsi_console_setup(struct console *console, char *options)
+{
+	struct hvsi_struct *hp;
+	int ret;
+
+	if (console->index < 0 || console->index >= hvsi_count)
+		return -EINVAL;
+	hp = &hvsi_ports[console->index];
+
+	/* give the FSP a chance to change the baud rate when we re-open */
+	hvsi_close_protocol(hp);
+
+	ret = hvsi_handshake(hp);
+	if (ret < 0)
+		return ret;
+
+	ret = hvsi_get_mctrl(hp);
+	if (ret < 0)
+		return ret;
+
+	ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
+	if (ret < 0)
+		return ret;
+
+	hp->flags |= HVSI_CONSOLE;
+
+	return 0;
+}
+
+static struct console hvsi_console = {
+	.name		= "hvsi",
+	.write		= hvsi_console_print,
+	.device		= hvsi_console_device,
+	.setup		= hvsi_console_setup,
+	.flags		= CON_PRINTBUFFER,
+	.index		= -1,
+};
+
+static int __init hvsi_console_init(void)
+{
+	struct device_node *vty;
+
+	hvsi_wait = poll_for_state; /* no irqs yet; must poll */
+
+	/* search device tree for vty nodes */
+	for_each_compatible_node(vty, "serial", "hvterm-protocol") {
+		struct hvsi_struct *hp;
+		const __be32 *vtermno, *irq;
+
+		vtermno = of_get_property(vty, "reg", NULL);
+		irq = of_get_property(vty, "interrupts", NULL);
+		if (!vtermno || !irq)
+			continue;
+
+		if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
+			of_node_put(vty);
+			break;
+		}
+
+		hp = &hvsi_ports[hvsi_count];
+		INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
+		INIT_WORK(&hp->handshaker, hvsi_handshaker);
+		init_waitqueue_head(&hp->emptyq);
+		init_waitqueue_head(&hp->stateq);
+		spin_lock_init(&hp->lock);
+		tty_port_init(&hp->port);
+		hp->index = hvsi_count;
+		hp->inbuf_end = hp->inbuf;
+		hp->state = HVSI_CLOSED;
+		hp->vtermno = be32_to_cpup(vtermno);
+		hp->virq = irq_create_mapping(NULL, be32_to_cpup(irq));
+		if (hp->virq == 0) {
+			printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
+			       __func__, be32_to_cpup(irq));
+			tty_port_destroy(&hp->port);
+			continue;
+		}
+
+		hvsi_count++;
+	}
+
+	if (hvsi_count)
+		register_console(&hvsi_console);
+	return 0;
+}
+console_initcall(hvsi_console_init);