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, 507 insertions, 0 deletions

diff --git a/drivers/parport/daisy.c b/drivers/parport/daisy.c
new file mode 100644
index 000000000..6d78ec3a7
--- /dev/null
+++ b/drivers/parport/daisy.c
@@ -0,0 +1,507 @@
+/*
+ * IEEE 1284.3 Parallel port daisy chain and multiplexor code
+ * 
+ * Copyright (C) 1999, 2000  Tim Waugh <tim@cyberelk.demon.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * ??-12-1998: Initial implementation.
+ * 31-01-1999: Make port-cloning transparent.
+ * 13-02-1999: Move DeviceID technique from parport_probe.
+ * 13-03-1999: Get DeviceID from non-IEEE 1284.3 devices too.
+ * 22-02-2000: Count devices that are actually detected.
+ *
+ * Any part of this program may be used in documents licensed under
+ * the GNU Free Documentation License, Version 1.1 or any later version
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/parport.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+
+#include <asm/current.h>
+#include <linux/uaccess.h>
+
+#undef DEBUG
+
+static struct daisydev {
+	struct daisydev *next;
+	struct parport *port;
+	int daisy;
+	int devnum;
+} *topology = NULL;
+static DEFINE_SPINLOCK(topology_lock);
+
+static int numdevs;
+static bool daisy_init_done;
+
+/* Forward-declaration of lower-level functions. */
+static int mux_present(struct parport *port);
+static int num_mux_ports(struct parport *port);
+static int select_port(struct parport *port);
+static int assign_addrs(struct parport *port);
+
+/* Add a device to the discovered topology. */
+static void add_dev(int devnum, struct parport *port, int daisy)
+{
+	struct daisydev *newdev, **p;
+	newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL);
+	if (newdev) {
+		newdev->port = port;
+		newdev->daisy = daisy;
+		newdev->devnum = devnum;
+		spin_lock(&topology_lock);
+		for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next)
+			;
+		newdev->next = *p;
+		*p = newdev;
+		spin_unlock(&topology_lock);
+	}
+}
+
+/* Clone a parport (actually, make an alias). */
+static struct parport *clone_parport(struct parport *real, int muxport)
+{
+	struct parport *extra = parport_register_port(real->base,
+						       real->irq,
+						       real->dma,
+						       real->ops);
+	if (extra) {
+		extra->portnum = real->portnum;
+		extra->physport = real;
+		extra->muxport = muxport;
+		real->slaves[muxport-1] = extra;
+	}
+
+	return extra;
+}
+
+static int daisy_drv_probe(struct pardevice *par_dev)
+{
+	struct device_driver *drv = par_dev->dev.driver;
+
+	if (strcmp(drv->name, "daisy_drv"))
+		return -ENODEV;
+	if (strcmp(par_dev->name, daisy_dev_name))
+		return -ENODEV;
+
+	return 0;
+}
+
+static struct parport_driver daisy_driver = {
+	.name = "daisy_drv",
+	.probe = daisy_drv_probe,
+	.devmodel = true,
+};
+
+/* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.
+ * Return value is number of devices actually detected. */
+int parport_daisy_init(struct parport *port)
+{
+	int detected = 0;
+	char *deviceid;
+	static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" };
+	int num_ports;
+	int i;
+	int last_try = 0;
+
+	if (!daisy_init_done) {
+		/*
+		 * flag should be marked true first as
+		 * parport_register_driver() might try to load the low
+		 * level driver which will lead to announcing new ports
+		 * and which will again come back here at
+		 * parport_daisy_init()
+		 */
+		daisy_init_done = true;
+		i = parport_register_driver(&daisy_driver);
+		if (i) {
+			pr_err("daisy registration failed\n");
+			daisy_init_done = false;
+			return i;
+		}
+	}
+
+again:
+	/* Because this is called before any other devices exist,
+	 * we don't have to claim exclusive access.  */
+
+	/* If mux present on normal port, need to create new
+	 * parports for each extra port. */
+	if (port->muxport < 0 && mux_present(port) &&
+	    /* don't be fooled: a mux must have 2 or 4 ports. */
+	    ((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) {
+		/* Leave original as port zero. */
+		port->muxport = 0;
+		pr_info("%s: 1st (default) port of %d-way multiplexor\n",
+			port->name, num_ports);
+		for (i = 1; i < num_ports; i++) {
+			/* Clone the port. */
+			struct parport *extra = clone_parport(port, i);
+			if (!extra) {
+				if (signal_pending(current))
+					break;
+
+				schedule();
+				continue;
+			}
+
+			pr_info("%s: %d%s port of %d-way multiplexor on %s\n",
+				extra->name, i + 1, th[i + 1], num_ports,
+				port->name);
+
+			/* Analyse that port too.  We won't recurse
+			   forever because of the 'port->muxport < 0'
+			   test above. */
+			parport_daisy_init(extra);
+		}
+	}
+
+	if (port->muxport >= 0)
+		select_port(port);
+
+	parport_daisy_deselect_all(port);
+	detected += assign_addrs(port);
+
+	/* Count the potential legacy device at the end. */
+	add_dev(numdevs++, port, -1);
+
+	/* Find out the legacy device's IEEE 1284 device ID. */
+	deviceid = kmalloc(1024, GFP_KERNEL);
+	if (deviceid) {
+		if (parport_device_id(numdevs - 1, deviceid, 1024) > 2)
+			detected++;
+
+		kfree(deviceid);
+	}
+
+	if (!detected && !last_try) {
+		/* No devices were detected.  Perhaps they are in some
+                   funny state; let's try to reset them and see if
+                   they wake up. */
+		parport_daisy_fini(port);
+		parport_write_control(port, PARPORT_CONTROL_SELECT);
+		udelay(50);
+		parport_write_control(port,
+				       PARPORT_CONTROL_SELECT |
+				       PARPORT_CONTROL_INIT);
+		udelay(50);
+		last_try = 1;
+		goto again;
+	}
+
+	return detected;
+}
+
+/* Forget about devices on a physical port. */
+void parport_daisy_fini(struct parport *port)
+{
+	struct daisydev **p;
+
+	spin_lock(&topology_lock);
+	p = &topology;
+	while (*p) {
+		struct daisydev *dev = *p;
+		if (dev->port != port) {
+			p = &dev->next;
+			continue;
+		}
+		*p = dev->next;
+		kfree(dev);
+	}
+
+	/* Gaps in the numbering could be handled better.  How should
+           someone enumerate through all IEEE1284.3 devices in the
+           topology?. */
+	if (!topology) numdevs = 0;
+	spin_unlock(&topology_lock);
+	return;
+}
+
+/**
+ *	parport_open - find a device by canonical device number
+ *	@devnum: canonical device number
+ *	@name: name to associate with the device
+ *
+ *	This function is similar to parport_register_device(), except
+ *	that it locates a device by its number rather than by the port
+ *	it is attached to.
+ *
+ *	All parameters except for @devnum are the same as for
+ *	parport_register_device().  The return value is the same as
+ *	for parport_register_device().
+ **/
+
+struct pardevice *parport_open(int devnum, const char *name)
+{
+	struct daisydev *p = topology;
+	struct pardev_cb par_cb;
+	struct parport *port;
+	struct pardevice *dev;
+	int daisy;
+
+	memset(&par_cb, 0, sizeof(par_cb));
+	spin_lock(&topology_lock);
+	while (p && p->devnum != devnum)
+		p = p->next;
+
+	if (!p) {
+		spin_unlock(&topology_lock);
+		return NULL;
+	}
+
+	daisy = p->daisy;
+	port = parport_get_port(p->port);
+	spin_unlock(&topology_lock);
+
+	dev = parport_register_dev_model(port, name, &par_cb, devnum);
+	parport_put_port(port);
+	if (!dev)
+		return NULL;
+
+	dev->daisy = daisy;
+
+	/* Check that there really is a device to select. */
+	if (daisy >= 0) {
+		int selected;
+		parport_claim_or_block(dev);
+		selected = port->daisy;
+		parport_release(dev);
+
+		if (selected != daisy) {
+			/* No corresponding device. */
+			parport_unregister_device(dev);
+			return NULL;
+		}
+	}
+
+	return dev;
+}
+
+/**
+ *	parport_close - close a device opened with parport_open()
+ *	@dev: device to close
+ *
+ *	This is to parport_open() as parport_unregister_device() is to
+ *	parport_register_device().
+ **/
+
+void parport_close(struct pardevice *dev)
+{
+	parport_unregister_device(dev);
+}
+
+/* Send a daisy-chain-style CPP command packet. */
+static int cpp_daisy(struct parport *port, int cmd)
+{
+	unsigned char s;
+
+	parport_data_forward(port);
+	parport_write_data(port, 0xaa); udelay(2);
+	parport_write_data(port, 0x55); udelay(2);
+	parport_write_data(port, 0x00); udelay(2);
+	parport_write_data(port, 0xff); udelay(2);
+	s = parport_read_status(port) & (PARPORT_STATUS_BUSY
+					  | PARPORT_STATUS_PAPEROUT
+					  | PARPORT_STATUS_SELECT
+					  | PARPORT_STATUS_ERROR);
+	if (s != (PARPORT_STATUS_BUSY
+		  | PARPORT_STATUS_PAPEROUT
+		  | PARPORT_STATUS_SELECT
+		  | PARPORT_STATUS_ERROR)) {
+		pr_debug("%s: cpp_daisy: aa5500ff(%02x)\n", port->name, s);
+		return -ENXIO;
+	}
+
+	parport_write_data(port, 0x87); udelay(2);
+	s = parport_read_status(port) & (PARPORT_STATUS_BUSY
+					  | PARPORT_STATUS_PAPEROUT
+					  | PARPORT_STATUS_SELECT
+					  | PARPORT_STATUS_ERROR);
+	if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
+		pr_debug("%s: cpp_daisy: aa5500ff87(%02x)\n", port->name, s);
+		return -ENXIO;
+	}
+
+	parport_write_data(port, 0x78); udelay(2);
+	parport_write_data(port, cmd); udelay(2);
+	parport_frob_control(port,
+			      PARPORT_CONTROL_STROBE,
+			      PARPORT_CONTROL_STROBE);
+	udelay(1);
+	s = parport_read_status(port);
+	parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
+	udelay(1);
+	parport_write_data(port, 0xff); udelay(2);
+
+	return s;
+}
+
+/* Send a mux-style CPP command packet. */
+static int cpp_mux(struct parport *port, int cmd)
+{
+	unsigned char s;
+	int rc;
+
+	parport_data_forward(port);
+	parport_write_data(port, 0xaa); udelay(2);
+	parport_write_data(port, 0x55); udelay(2);
+	parport_write_data(port, 0xf0); udelay(2);
+	parport_write_data(port, 0x0f); udelay(2);
+	parport_write_data(port, 0x52); udelay(2);
+	parport_write_data(port, 0xad); udelay(2);
+	parport_write_data(port, cmd); udelay(2);
+
+	s = parport_read_status(port);
+	if (!(s & PARPORT_STATUS_ACK)) {
+		pr_debug("%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",
+			 port->name, cmd, s);
+		return -EIO;
+	}
+
+	rc = (((s & PARPORT_STATUS_SELECT   ? 1 : 0) << 0) |
+	      ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |
+	      ((s & PARPORT_STATUS_BUSY     ? 0 : 1) << 2) |
+	      ((s & PARPORT_STATUS_ERROR    ? 0 : 1) << 3));
+
+	return rc;
+}
+
+void parport_daisy_deselect_all(struct parport *port)
+{
+	cpp_daisy(port, 0x30);
+}
+
+int parport_daisy_select(struct parport *port, int daisy, int mode)
+{
+	switch (mode)
+	{
+		// For these modes we should switch to EPP mode:
+		case IEEE1284_MODE_EPP:
+		case IEEE1284_MODE_EPPSL:
+		case IEEE1284_MODE_EPPSWE:
+			return !(cpp_daisy(port, 0x20 + daisy) &
+				 PARPORT_STATUS_ERROR);
+
+		// For these modes we should switch to ECP mode:
+		case IEEE1284_MODE_ECP:
+		case IEEE1284_MODE_ECPRLE:
+		case IEEE1284_MODE_ECPSWE: 
+			return !(cpp_daisy(port, 0xd0 + daisy) &
+				 PARPORT_STATUS_ERROR);
+
+		// Nothing was told for BECP in Daisy chain specification.
+		// May be it's wise to use ECP?
+		case IEEE1284_MODE_BECP:
+		// Others use compat mode
+		case IEEE1284_MODE_NIBBLE:
+		case IEEE1284_MODE_BYTE:
+		case IEEE1284_MODE_COMPAT:
+		default:
+			return !(cpp_daisy(port, 0xe0 + daisy) &
+				 PARPORT_STATUS_ERROR);
+	}
+}
+
+static int mux_present(struct parport *port)
+{
+	return cpp_mux(port, 0x51) == 3;
+}
+
+static int num_mux_ports(struct parport *port)
+{
+	return cpp_mux(port, 0x58);
+}
+
+static int select_port(struct parport *port)
+{
+	int muxport = port->muxport;
+	return cpp_mux(port, 0x60 + muxport) == muxport;
+}
+
+static int assign_addrs(struct parport *port)
+{
+	unsigned char s;
+	unsigned char daisy;
+	int thisdev = numdevs;
+	int detected;
+	char *deviceid;
+
+	parport_data_forward(port);
+	parport_write_data(port, 0xaa); udelay(2);
+	parport_write_data(port, 0x55); udelay(2);
+	parport_write_data(port, 0x00); udelay(2);
+	parport_write_data(port, 0xff); udelay(2);
+	s = parport_read_status(port) & (PARPORT_STATUS_BUSY
+					  | PARPORT_STATUS_PAPEROUT
+					  | PARPORT_STATUS_SELECT
+					  | PARPORT_STATUS_ERROR);
+	if (s != (PARPORT_STATUS_BUSY
+		  | PARPORT_STATUS_PAPEROUT
+		  | PARPORT_STATUS_SELECT
+		  | PARPORT_STATUS_ERROR)) {
+		pr_debug("%s: assign_addrs: aa5500ff(%02x)\n", port->name, s);
+		return 0;
+	}
+
+	parport_write_data(port, 0x87); udelay(2);
+	s = parport_read_status(port) & (PARPORT_STATUS_BUSY
+					  | PARPORT_STATUS_PAPEROUT
+					  | PARPORT_STATUS_SELECT
+					  | PARPORT_STATUS_ERROR);
+	if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
+		pr_debug("%s: assign_addrs: aa5500ff87(%02x)\n", port->name, s);
+		return 0;
+	}
+
+	parport_write_data(port, 0x78); udelay(2);
+	s = parport_read_status(port);
+
+	for (daisy = 0;
+	     (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
+		     == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
+		     && daisy < 4;
+	     ++daisy) {
+		parport_write_data(port, daisy);
+		udelay(2);
+		parport_frob_control(port,
+				      PARPORT_CONTROL_STROBE,
+				      PARPORT_CONTROL_STROBE);
+		udelay(1);
+		parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
+		udelay(1);
+
+		add_dev(numdevs++, port, daisy);
+
+		/* See if this device thought it was the last in the
+		 * chain. */
+		if (!(s & PARPORT_STATUS_BUSY))
+			break;
+
+		/* We are seeing pass through status now. We see
+		   last_dev from next device or if last_dev does not
+		   work status lines from some non-daisy chain
+		   device. */
+		s = parport_read_status(port);
+	}
+
+	parport_write_data(port, 0xff); udelay(2);
+	detected = numdevs - thisdev;
+	pr_debug("%s: Found %d daisy-chained devices\n", port->name, detected);
+
+	/* Ask the new devices to introduce themselves. */
+	deviceid = kmalloc(1024, GFP_KERNEL);
+	if (!deviceid) return 0;
+
+	for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)
+		parport_device_id(thisdev, deviceid, 1024);
+
+	kfree(deviceid);
+	return detected;
+}