staging: ozwpan: Added USB HCD implementation

Added the implementation of the virtual USB HCD that is used to
present devices connected via the network to the USB subsystem.

Signed-off-by: Chris Kelly <ckelly@ozmodevices.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 2272 insertions, 0 deletions

diff --git a/drivers/staging/ozwpan/ozhcd.c b/drivers/staging/ozwpan/ozhcd.c
new file mode 100644
index 000000000000..775dfe9c7b85
--- /dev/null
+++ b/drivers/staging/ozwpan/ozhcd.c
@@ -0,0 +1,2257 @@
+/* -----------------------------------------------------------------------------
+ * Copyright (c) 2011 Ozmo Inc
+ * Released under the GNU General Public License Version 2 (GPLv2).
+ *
+ * This file provides the implementation of a USB host controller device that
+ * does not have any associated hardware. Instead the virtual device is
+ * connected to the WiFi network and emulates the operation of a USB hcd by
+ * receiving and sending network frames.
+ * Note:
+ * We take great pains to reduce the amount of code where interrupts need to be
+ * disabled and in this respect we are different from standard HCD's. In
+ * particular we don't want in_irq() code bleeding over to the protocol side of
+ * the driver.
+ * The troublesome functions are the urb enqueue and dequeue functions both of
+ * which can be called in_irq(). So for these functions we put the urbs into a
+ * queue and request a tasklet to process them. This means that a spinlock with
+ * interrupts disabled must be held for insertion and removal but most code is
+ * is in tasklet or soft irq context. The lock that protects this list is called
+ * the tasklet lock and serves the purpose of the 'HCD lock' which must be held
+ * when calling the following functions.
+ *   usb_hcd_link_urb_to_ep()
+ *   usb_hcd_unlink_urb_from_ep()
+ *   usb_hcd_flush_endpoint()
+ *   usb_hcd_check_unlink_urb()
+ * -----------------------------------------------------------------------------
+ */
+#include <linux/platform_device.h>
+#include <linux/usb.h>
+#include <linux/jiffies.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include "linux/usb/hcd.h"
+#include <asm/unaligned.h>
+#include "ozconfig.h"
+#include "ozusbif.h"
+#include "oztrace.h"
+#include "ozalloc.h"
+#include "ozurbparanoia.h"
+#include "ozevent.h"
+/*------------------------------------------------------------------------------
+ * Number of units of buffering to capture for an isochronous IN endpoint before
+ * allowing data to be indicated up.
+ */
+#define OZ_IN_BUFFERING_UNITS	50
+/* Name of our platform device.
+ */
+#define OZ_PLAT_DEV_NAME	"ozwpan"
+/* Maximum number of free urb links that can be kept in the pool.
+ */
+#define OZ_MAX_LINK_POOL_SIZE	16
+/* Get endpoint object from the containing link.
+ */
+#define ep_from_link(__e) container_of((__e), struct oz_endpoint, link)
+/*------------------------------------------------------------------------------
+ * Used to link urbs together and also store some status information for each
+ * urb.
+ * A cache of these are kept in a pool to reduce number of calls to kmalloc.
+ */
+struct oz_urb_link {
+	struct list_head link;
+	struct urb *urb;
+	struct oz_port *port;
+	u8 req_id;
+	u8 ep_num;
+	unsigned long submit_jiffies;
+};
+
+/* Holds state information about a USB endpoint.
+ */
+struct oz_endpoint {
+	struct list_head urb_list;	/* List of oz_urb_link items. */
+	struct list_head link;		/* For isoc ep, links in to isoc
+					   lists of oz_port. */
+	unsigned long last_jiffies;
+	int credit;
+	int credit_ceiling;
+	u8 ep_num;
+	u8 attrib;
+	u8 *buffer;
+	int buffer_size;
+	int in_ix;
+	int out_ix;
+	int buffered_units;
+	unsigned flags;
+	int start_frame;
+};
+/* Bits in the flags field. */
+#define OZ_F_EP_BUFFERING	0x1
+#define OZ_F_EP_HAVE_STREAM	0x2
+
+/* Holds state information about a USB interface.
+ */
+struct oz_interface {
+	unsigned ep_mask;
+	u8 alt;
+};
+
+/* Holds state information about an hcd port.
+ */
+#define OZ_NB_ENDPOINTS	16
+struct oz_port {
+	unsigned flags;
+	unsigned status;
+	void *hpd;
+	struct oz_hcd *ozhcd;
+	spinlock_t port_lock;
+	u8 bus_addr;
+	u8 next_req_id;
+	u8 config_num;
+	int num_iface;
+	struct oz_interface *iface;
+	struct oz_endpoint *out_ep[OZ_NB_ENDPOINTS];
+	struct oz_endpoint *in_ep[OZ_NB_ENDPOINTS];
+	struct list_head isoc_out_ep;
+	struct list_head isoc_in_ep;
+};
+#define OZ_PORT_F_PRESENT	0x1
+#define OZ_PORT_F_CHANGED	0x2
+#define OZ_PORT_F_DYING		0x4
+
+/* Data structure in the private context area of struct usb_hcd.
+ */
+#define OZ_NB_PORTS	8
+struct oz_hcd {
+	spinlock_t hcd_lock;
+	struct list_head urb_pending_list;
+	struct list_head urb_cancel_list;
+	struct list_head orphanage;
+	int conn_port; /* Port that is currently connecting, -1 if none.*/
+	struct oz_port ports[OZ_NB_PORTS];
+	uint flags;
+	struct usb_hcd *hcd;
+};
+/* Bits in flags field.
+ */
+#define OZ_HDC_F_SUSPENDED	0x1
+
+/*------------------------------------------------------------------------------
+ * Static function prototypes.
+ */
+static int oz_hcd_start(struct usb_hcd *hcd);
+static void oz_hcd_stop(struct usb_hcd *hcd);
+static void oz_hcd_shutdown(struct usb_hcd *hcd);
+static int oz_hcd_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
+				gfp_t mem_flags);
+static int oz_hcd_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status);
+static void oz_hcd_endpoint_disable(struct usb_hcd *hcd,
+				struct usb_host_endpoint *ep);
+static void oz_hcd_endpoint_reset(struct usb_hcd *hcd,
+				struct usb_host_endpoint *ep);
+static int oz_hcd_get_frame_number(struct usb_hcd *hcd);
+static int oz_hcd_hub_status_data(struct usb_hcd *hcd, char *buf);
+static int oz_hcd_hub_control(struct usb_hcd *hcd, u16 req_type, u16 wvalue,
+				u16 windex, char *buf, u16 wlength);
+static int oz_hcd_bus_suspend(struct usb_hcd *hcd);
+static int oz_hcd_bus_resume(struct usb_hcd *hcd);
+static int oz_plat_probe(struct platform_device *dev);
+static int oz_plat_remove(struct platform_device *dev);
+static void oz_plat_shutdown(struct platform_device *dev);
+static int oz_plat_suspend(struct platform_device *dev, pm_message_t msg);
+static int oz_plat_resume(struct platform_device *dev);
+static void oz_urb_process_tasklet(unsigned long unused);
+static int oz_build_endpoints_for_config(struct usb_hcd *hcd,
+		struct oz_port *port, struct usb_host_config *config,
+		gfp_t mem_flags);
+static void oz_clean_endpoints_for_config(struct usb_hcd *hcd,
+				struct oz_port *port);
+static int oz_build_endpoints_for_interface(struct usb_hcd *hcd,
+			struct oz_port *port,
+			struct usb_host_interface *intf, gfp_t mem_flags);
+static void oz_clean_endpoints_for_interface(struct usb_hcd *hcd,
+			struct oz_port *port, int if_ix);
+static void oz_process_ep0_urb(struct oz_hcd *ozhcd, struct urb *urb,
+		gfp_t mem_flags);
+static struct oz_urb_link *oz_remove_urb(struct oz_endpoint *ep,
+		struct urb *urb);
+static void oz_hcd_clear_orphanage(struct oz_hcd *ozhcd, int status);
+/*------------------------------------------------------------------------------
+ * Static external variables.
+ */
+static struct platform_device *g_plat_dev;
+static struct oz_hcd *g_ozhcd;
+static DEFINE_SPINLOCK(g_hcdlock);	/* Guards g_ozhcd. */
+static const char g_hcd_name[] = "Ozmo WPAN";
+static struct list_head *g_link_pool;
+static int g_link_pool_size;
+static DEFINE_SPINLOCK(g_link_lock);
+static DEFINE_SPINLOCK(g_tasklet_lock);
+static struct tasklet_struct g_urb_process_tasklet;
+static struct tasklet_struct g_urb_cancel_tasklet;
+static atomic_t g_pending_urbs = ATOMIC_INIT(0);
+static const struct hc_driver g_oz_hc_drv = {
+	.description =		g_hcd_name,
+	.product_desc =		"Ozmo Devices WPAN",
+	.hcd_priv_size =	sizeof(struct oz_hcd),
+	.flags =		HCD_USB11,
+	.start =		oz_hcd_start,
+	.stop =			oz_hcd_stop,
+	.shutdown =		oz_hcd_shutdown,
+	.urb_enqueue =		oz_hcd_urb_enqueue,
+	.urb_dequeue =		oz_hcd_urb_dequeue,
+	.endpoint_disable =	oz_hcd_endpoint_disable,
+	.endpoint_reset =	oz_hcd_endpoint_reset,
+	.get_frame_number =	oz_hcd_get_frame_number,
+	.hub_status_data =	oz_hcd_hub_status_data,
+	.hub_control =		oz_hcd_hub_control,
+	.bus_suspend =		oz_hcd_bus_suspend,
+	.bus_resume =		oz_hcd_bus_resume,
+};
+
+static struct platform_driver g_oz_plat_drv = {
+	.probe = oz_plat_probe,
+	.remove = oz_plat_remove,
+	.shutdown = oz_plat_shutdown,
+	.suspend = oz_plat_suspend,
+	.resume = oz_plat_resume,
+	.driver = {
+		.name = OZ_PLAT_DEV_NAME,
+		.owner = THIS_MODULE,
+	},
+};
+/*------------------------------------------------------------------------------
+ * Gets our private context area (which is of type struct oz_hcd) from the
+ * usb_hcd structure.
+ * Context: any
+ */
+static inline struct oz_hcd *oz_hcd_private(struct usb_hcd *hcd)
+{
+	return (struct oz_hcd *)hcd->hcd_priv;
+}
+/*------------------------------------------------------------------------------
+ * Searches list of ports to find the index of the one with a specified  USB
+ * bus address. If none of the ports has the bus address then the connection
+ * port is returned, if there is one or -1 otherwise.
+ * Context: any
+ */
+static int oz_get_port_from_addr(struct oz_hcd *ozhcd, u8 bus_addr)
+{
+	int i;
+	for (i = 0; i < OZ_NB_PORTS; i++) {
+		if (ozhcd->ports[i].bus_addr == bus_addr)
+			return i;
+	}
+	return ozhcd->conn_port;
+}
+/*------------------------------------------------------------------------------
+ * Allocates an urb link, first trying the pool but going to heap if empty.
+ * Context: any
+ */
+static struct oz_urb_link *oz_alloc_urb_link(void)
+{
+	struct oz_urb_link *urbl = 0;
+	unsigned long irq_state;
+	spin_lock_irqsave(&g_link_lock, irq_state);
+	if (g_link_pool) {
+		urbl = container_of(g_link_pool, struct oz_urb_link, link);
+		g_link_pool = urbl->link.next;
+		--g_link_pool_size;
+	}
+	spin_unlock_irqrestore(&g_link_lock, irq_state);
+	if (urbl == 0)
+		urbl = oz_alloc(sizeof(struct oz_urb_link), GFP_ATOMIC);
+	return urbl;
+}
+/*------------------------------------------------------------------------------
+ * Frees an urb link by putting it in the pool if there is enough space or
+ * deallocating it to heap otherwise.
+ * Context: any
+ */
+static void oz_free_urb_link(struct oz_urb_link *urbl)
+{
+	if (urbl) {
+		unsigned long irq_state;
+		spin_lock_irqsave(&g_link_lock, irq_state);
+		if (g_link_pool_size < OZ_MAX_LINK_POOL_SIZE) {
+			urbl->link.next = g_link_pool;
+			g_link_pool = &urbl->link;
+			urbl = 0;
+			g_link_pool_size++;
+		}
+		spin_unlock_irqrestore(&g_link_lock, irq_state);
+		if (urbl)
+			oz_free(urbl);
+	}
+}
+/*------------------------------------------------------------------------------
+ * Deallocates all the urb links in the pool.
+ * Context: unknown
+ */
+static void oz_empty_link_pool(void)
+{
+	struct list_head *e;
+	unsigned long irq_state;
+	spin_lock_irqsave(&g_link_lock, irq_state);
+	e = g_link_pool;
+	g_link_pool = 0;
+	g_link_pool_size = 0;
+	spin_unlock_irqrestore(&g_link_lock, irq_state);
+	while (e) {
+		struct oz_urb_link *urbl =
+			container_of(e, struct oz_urb_link, link);
+		e = e->next;
+		oz_free(urbl);
+	}
+}
+/*------------------------------------------------------------------------------
+ * Allocates endpoint structure and optionally a buffer. If a buffer is
+ * allocated it immediately follows the endpoint structure.
+ * Context: softirq
+ */
+static struct oz_endpoint *oz_ep_alloc(gfp_t mem_flags, int buffer_size)
+{
+	struct oz_endpoint *ep =
+		oz_alloc(sizeof(struct oz_endpoint)+buffer_size, mem_flags);
+	if (ep) {
+		memset(ep, 0, sizeof(*ep));
+		INIT_LIST_HEAD(&ep->urb_list);
+		INIT_LIST_HEAD(&ep->link);
+		ep->credit = -1;
+		if (buffer_size) {
+			ep->buffer_size = buffer_size;
+			ep->buffer = (u8 *)(ep+1);
+		}
+	}
+	return ep;
+}
+/*------------------------------------------------------------------------------
+ * Pre-condition: Must be called with g_tasklet_lock held and interrupts
+ * disabled.
+ * Context: softirq or process
+ */
+struct oz_urb_link *oz_uncancel_urb(struct oz_hcd *ozhcd, struct urb *urb)
+{
+	struct oz_urb_link *urbl;
+	struct list_head *e;
+	list_for_each(e, &ozhcd->urb_cancel_list) {
+		urbl = container_of(e, struct oz_urb_link, link);
+		if (urb == urbl->urb) {
+			list_del_init(e);
+			return urbl;
+		}
+	}
+	return 0;
+}
+/*------------------------------------------------------------------------------
+ * This is called when we have finished processing an urb. It unlinks it from
+ * the ep and returns it to the core.
+ * Context: softirq or process
+ */
+static void oz_complete_urb(struct usb_hcd *hcd, struct urb *urb,
+		int status, unsigned long submit_jiffies)
+{
+	struct oz_hcd *ozhcd = oz_hcd_private(hcd);
+	unsigned long irq_state;
+	struct oz_urb_link *cancel_urbl = 0;
+	spin_lock_irqsave(&g_tasklet_lock, irq_state);
+	usb_hcd_unlink_urb_from_ep(hcd, urb);
+	/* Clear hcpriv which will prevent it being put in the cancel list
+	 * in the event that an attempt is made to cancel it.
+	 */
+	urb->hcpriv = 0;
+	/* Walk the cancel list in case the urb is already sitting there.
+	 * Since we process the cancel list in a tasklet rather than in
+	 * the dequeue function this could happen.
+	 */
+	cancel_urbl = oz_uncancel_urb(ozhcd, urb);
+	/* Note: we release lock but do not enable local irqs.
+	 * It appears that usb_hcd_giveback_urb() expects irqs to be disabled,
+	 * or at least other host controllers disable interrupts at this point
+	 * so we do the same. We must, however, release the lock otherwise a
+	 * deadlock will occur if an urb is submitted to our driver in the urb
+	 * completion function. Because we disable interrupts it is possible
+	 * that the urb_enqueue function can be called with them disabled.
+	 */
+	spin_unlock(&g_tasklet_lock);
+	if (oz_forget_urb(urb)) {
+		oz_trace("OZWPAN: ERROR Unknown URB %p\n", urb);
+	} else {
+		static unsigned long last_time;
+		atomic_dec(&g_pending_urbs);
+		oz_trace2(OZ_TRACE_URB,
+			"%lu: giveback_urb(%p,%x) %lu %lu pending:%d\n",
+			jiffies, urb, status, jiffies-submit_jiffies,
+			jiffies-last_time, atomic_read(&g_pending_urbs));
+		last_time = jiffies;
+		oz_event_log(OZ_EVT_URB_DONE, 0, 0, urb, status);
+		usb_hcd_giveback_urb(hcd, urb, status);
+	}
+	spin_lock(&g_tasklet_lock);
+	spin_unlock_irqrestore(&g_tasklet_lock, irq_state);
+	if (cancel_urbl)
+		oz_free_urb_link(cancel_urbl);
+}
+/*------------------------------------------------------------------------------
+ * Deallocates an endpoint including deallocating any associated stream and
+ * returning any queued urbs to the core.
+ * Context: softirq
+ */
+static void oz_ep_free(struct oz_port *port, struct oz_endpoint *ep)
+{
+	oz_trace("oz_ep_free()\n");
+	if (port) {
+		struct list_head list;
+		struct oz_hcd *ozhcd = port->ozhcd;
+		INIT_LIST_HEAD(&list);
+		if (ep->flags & OZ_F_EP_HAVE_STREAM)
+			oz_usb_stream_delete(port->hpd, ep->ep_num);
+		/* Transfer URBs to the orphanage while we hold the lock. */
+		spin_lock_bh(&ozhcd->hcd_lock);
+		/* Note: this works even if ep->urb_list is empty.*/
+		list_replace_init(&ep->urb_list, &list);
+		/* Put the URBs in the orphanage. */
+		list_splice_tail(&list, &ozhcd->orphanage);
+		spin_unlock_bh(&ozhcd->hcd_lock);
+	}
+	oz_trace("Freeing endpoint memory\n");
+	oz_free(ep);
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq
+ */
+static int oz_enqueue_ep_urb(struct oz_port *port, u8 ep_addr, int in_dir,
+			struct urb *urb, u8 req_id)
+{
+	struct oz_urb_link *urbl;
+	struct oz_endpoint *ep;
+	int err = 0;
+	if (ep_addr >= OZ_NB_ENDPOINTS) {
+		oz_trace("Invalid endpoint number in oz_enqueue_ep_urb().\n");
+		return -EINVAL;
+	}
+	urbl = oz_alloc_urb_link();
+	if (!urbl)
+		return -ENOMEM;
+	urbl->submit_jiffies = jiffies;
+	urbl->urb = urb;
+	urbl->req_id = req_id;
+	urbl->ep_num = ep_addr;
+	/* Hold lock while we insert the URB into the list within the
+	 * endpoint structure.
+	 */
+	spin_lock_bh(&port->ozhcd->hcd_lock);
+	/* If the urb has been unlinked while out of any list then
+	 * complete it now.
+	 */
+	if (urb->unlinked) {
+		spin_unlock_bh(&port->ozhcd->hcd_lock);
+		oz_trace("urb %p unlinked so complete immediately\n", urb);
+		oz_complete_urb(port->ozhcd->hcd, urb, 0, 0);
+		oz_free_urb_link(urbl);
+		return 0;
+	}
+	if (in_dir)
+		ep = port->in_ep[ep_addr];
+	else
+		ep = port->out_ep[ep_addr];
+	if (ep && port->hpd) {
+		list_add_tail(&urbl->link, &ep->urb_list);
+		if (!in_dir && ep_addr && (ep->credit < 0)) {
+			ep->last_jiffies = jiffies;
+			ep->credit = 0;
+			oz_event_log(OZ_EVT_EP_CREDIT, ep->ep_num,
+					0, 0, ep->credit);
+		}
+	} else {
+		err = -EPIPE;
+	}
+	spin_unlock_bh(&port->ozhcd->hcd_lock);
+	if (err)
+		oz_free_urb_link(urbl);
+	return err;
+}
+/*------------------------------------------------------------------------------
+ * Removes an urb from the queue in the endpoint.
+ * Returns 0 if it is found and -EIDRM otherwise.
+ * Context: softirq
+ */
+static int oz_dequeue_ep_urb(struct oz_port *port, u8 ep_addr, int in_dir,
+			struct urb *urb)
+{
+	struct oz_urb_link *urbl = 0;
+	struct oz_endpoint *ep;
+	spin_lock_bh(&port->ozhcd->hcd_lock);
+	if (in_dir)
+		ep = port->in_ep[ep_addr];
+	else
+		ep = port->out_ep[ep_addr];
+	if (ep) {
+		struct list_head *e;
+		list_for_each(e, &ep->urb_list) {
+			urbl = container_of(e, struct oz_urb_link, link);
+			if (urbl->urb == urb) {
+				list_del_init(e);
+				break;
+			}
+			urbl = 0;
+		}
+	}
+	spin_unlock_bh(&port->ozhcd->hcd_lock);
+	if (urbl)
+		oz_free_urb_link(urbl);
+	return urbl ? 0 : -EIDRM;
+}
+/*------------------------------------------------------------------------------
+ * Finds an urb given its request id.
+ * Context: softirq
+ */
+static struct urb *oz_find_urb_by_id(struct oz_port *port, int ep_ix,
+		u8 req_id)
+{
+	struct oz_hcd *ozhcd = port->ozhcd;
+	struct urb *urb = 0;
+	struct oz_urb_link *urbl = 0;
+	struct oz_endpoint *ep;
+
+	spin_lock_bh(&ozhcd->hcd_lock);
+	ep = port->out_ep[ep_ix];
+	if (ep) {
+		struct list_head *e;
+		list_for_each(e, &ep->urb_list) {
+			urbl = container_of(e, struct oz_urb_link, link);
+			if (urbl->req_id == req_id) {
+				urb = urbl->urb;
+				list_del_init(e);
+				break;
+			}
+		}
+	}
+	spin_unlock_bh(&ozhcd->hcd_lock);
+	/* If urb is non-zero then we we must have an urb link to delete.
+	 */
+	if (urb)
+		oz_free_urb_link(urbl);
+	return urb;
+}
+/*------------------------------------------------------------------------------
+ * Pre-condition: Port lock must be held.
+ * Context: softirq
+ */
+static void oz_acquire_port(struct oz_port *port, void *hpd)
+{
+	INIT_LIST_HEAD(&port->isoc_out_ep);
+	INIT_LIST_HEAD(&port->isoc_in_ep);
+	port->flags |= OZ_PORT_F_PRESENT | OZ_PORT_F_CHANGED;
+	port->status |= USB_PORT_STAT_CONNECTION |
+			(USB_PORT_STAT_C_CONNECTION << 16);
+	oz_usb_get(hpd);
+	port->hpd = hpd;
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq
+ */
+static struct oz_hcd *oz_hcd_claim(void)
+{
+	struct oz_hcd *ozhcd;
+	spin_lock_bh(&g_hcdlock);
+	ozhcd = g_ozhcd;
+	if (ozhcd)
+		usb_get_hcd(ozhcd->hcd);
+	spin_unlock_bh(&g_hcdlock);
+	return ozhcd;
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq
+ */
+static inline void oz_hcd_put(struct oz_hcd *ozhcd)
+{
+	if (ozhcd)
+		usb_put_hcd(ozhcd->hcd);
+}
+/*------------------------------------------------------------------------------
+ * This is called by the protocol handler to notify that a PD has arrived.
+ * We allocate a port to associate with the PD and create a structure for
+ * endpoint 0. This port is made the connection port.
+ * In the event that one of the other port is already a connection port then
+ * we fail.
+ * TODO We should be able to do better than fail and should be able remember
+ * that this port needs configuring and make it the connection port once the
+ * current connection port has been assigned an address. Collisions here are
+ * probably very rare indeed.
+ * Context: softirq
+ */
+void *oz_hcd_pd_arrived(void *hpd)
+{
+	int i;
+	void *hport = 0;
+	struct oz_hcd *ozhcd = 0;
+	struct oz_endpoint *ep;
+	oz_trace("oz_hcd_pd_arrived()\n");
+	ozhcd = oz_hcd_claim();
+	if (ozhcd == 0)
+		return 0;
+	/* Allocate an endpoint object in advance (before holding hcd lock) to
+	 * use for out endpoint 0.
+	 */
+	ep = oz_ep_alloc(GFP_ATOMIC, 0);
+	spin_lock_bh(&ozhcd->hcd_lock);
+	if (ozhcd->conn_port >= 0) {
+		spin_unlock_bh(&ozhcd->hcd_lock);
+		oz_trace("conn_port >= 0\n");
+		goto out;
+	}
+	for (i = 0; i < OZ_NB_PORTS; i++) {
+		struct oz_port *port = &ozhcd->ports[i];
+		spin_lock(&port->port_lock);
+		if ((port->flags & OZ_PORT_F_PRESENT) == 0) {
+			oz_acquire_port(port, hpd);
+			spin_unlock(&port->port_lock);
+			break;
+		}
+		spin_unlock(&port->port_lock);
+	}
+	if (i < OZ_NB_PORTS) {
+		oz_trace("Setting conn_port = %d\n", i);
+		ozhcd->conn_port = i;
+		/* Attach out endpoint 0.
+		 */
+		ozhcd->ports[i].out_ep[0] = ep;
+		ep = 0;
+		hport = &ozhcd->ports[i];
+		spin_unlock_bh(&ozhcd->hcd_lock);
+		if (ozhcd->flags & OZ_HDC_F_SUSPENDED) {
+			oz_trace("Resuming root hub\n");
+			usb_hcd_resume_root_hub(ozhcd->hcd);
+		}
+		usb_hcd_poll_rh_status(ozhcd->hcd);
+	} else {
+		spin_unlock_bh(&ozhcd->hcd_lock);
+	}
+out:
+	if (ep) /* ep is non-null if not used. */
+		oz_ep_free(0, ep);
+	oz_hcd_put(ozhcd);
+	return hport;
+}
+/*------------------------------------------------------------------------------
+ * This is called by the protocol handler to notify that the PD has gone away.
+ * We need to deallocate all resources and then request that the root hub is
+ * polled. We release the reference we hold on the PD.
+ * Context: softirq
+ */
+void oz_hcd_pd_departed(void *hport)
+{
+	struct oz_port *port = (struct oz_port *)hport;
+	struct oz_hcd *ozhcd;
+	void *hpd;
+	struct oz_endpoint *ep = 0;
+
+	oz_trace("oz_hcd_pd_departed()\n");
+	if (port == 0) {
+		oz_trace("oz_hcd_pd_departed() port = 0\n");
+		return;
+	}
+	ozhcd = port->ozhcd;
+	if (ozhcd == 0)
+		return;
+	/* Check if this is the connection port - if so clear it.
+	 */
+	spin_lock_bh(&ozhcd->hcd_lock);
+	if ((ozhcd->conn_port >= 0) &&
+		(port == &ozhcd->ports[ozhcd->conn_port])) {
+		oz_trace("Clearing conn_port\n");
+		ozhcd->conn_port = -1;
+	}
+	spin_lock(&port->port_lock);
+	port->flags |= OZ_PORT_F_DYING;
+	spin_unlock(&port->port_lock);
+	spin_unlock_bh(&ozhcd->hcd_lock);
+
+	oz_clean_endpoints_for_config(ozhcd->hcd, port);
+	spin_lock_bh(&port->port_lock);
+	hpd = port->hpd;
+	port->hpd = 0;
+	port->bus_addr = 0xff;
+	port->flags &= ~(OZ_PORT_F_PRESENT | OZ_PORT_F_DYING);
+	port->flags |= OZ_PORT_F_CHANGED;
+	port->status &= ~USB_PORT_STAT_CONNECTION;
+	port->status |= (USB_PORT_STAT_C_CONNECTION << 16);
+	/* If there is an endpont 0 then clear the pointer while we hold
+	 * the spinlock be we deallocate it after releasing the lock.
+	 */
+	if (port->out_ep[0]) {
+		ep = port->out_ep[0];
+		port->out_ep[0] = 0;
+	}
+	spin_unlock_bh(&port->port_lock);
+	if (ep)
+		oz_ep_free(port, ep);
+	usb_hcd_poll_rh_status(ozhcd->hcd);
+	oz_usb_put(hpd);
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq
+ */
+void oz_hcd_pd_reset(void *hpd, void *hport)
+{
+	/* Cleanup the current configuration and report reset to the core.
+	 */
+	struct oz_port *port = (struct oz_port *)hport;
+	struct oz_hcd *ozhcd = port->ozhcd;
+	oz_trace("PD Reset\n");
+	spin_lock_bh(&port->port_lock);
+	port->flags |= OZ_PORT_F_CHANGED;
+	port->status |= USB_PORT_STAT_RESET;
+	port->status |= (USB_PORT_STAT_C_RESET << 16);
+	spin_unlock_bh(&port->port_lock);
+	oz_clean_endpoints_for_config(ozhcd->hcd, port);
+	usb_hcd_poll_rh_status(ozhcd->hcd);
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq
+ */
+void oz_hcd_get_desc_cnf(void *hport, u8 req_id, int status, u8 *desc,
+			int length, int offset, int total_size)
+{
+	struct oz_port *port = (struct oz_port *)hport;
+	struct urb *urb;
+	int err = 0;
+
+	oz_event_log(OZ_EVT_CTRL_CNF, 0, req_id, 0, status);
+	oz_trace("oz_hcd_get_desc_cnf length = %d offs = %d tot_size = %d\n",
+			length, offset, total_size);
+	urb = oz_find_urb_by_id(port, 0, req_id);
+	if (!urb)
+		return;
+	if (status == 0) {
+		int copy_len;
+		int required_size = urb->transfer_buffer_length;
+		if (required_size > total_size)
+			required_size = total_size;
+		copy_len = required_size-offset;
+		if (length <= copy_len)
+			copy_len = length;
+		memcpy(urb->transfer_buffer+offset, desc, copy_len);
+		offset += copy_len;
+		if (offset < required_size) {
+			struct usb_ctrlrequest *setup =
+				(struct usb_ctrlrequest *)urb->setup_packet;
+			unsigned wvalue = le16_to_cpu(setup->wValue);
+			if (oz_enqueue_ep_urb(port, 0, 0, urb, req_id))
+				err = -ENOMEM;
+			else if (oz_usb_get_desc_req(port->hpd, req_id,
+					setup->bRequestType, (u8)(wvalue>>8),
+					(u8)wvalue, setup->wIndex, offset,
+					required_size-offset)) {
+				oz_dequeue_ep_urb(port, 0, 0, urb);
+				err = -ENOMEM;
+			}
+			if (err == 0)
+				return;
+		}
+	}
+	urb->actual_length = total_size;
+	oz_complete_urb(port->ozhcd->hcd, urb, 0, 0);
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq
+ */
+#ifdef WANT_TRACE
+static void oz_display_conf_type(u8 t)
+{
+	switch (t) {
+	case USB_REQ_GET_STATUS:
+		oz_trace("USB_REQ_GET_STATUS - cnf\n");
+		break;
+	case USB_REQ_CLEAR_FEATURE:
+		oz_trace("USB_REQ_CLEAR_FEATURE - cnf\n");
+		break;
+	case USB_REQ_SET_FEATURE:
+		oz_trace("USB_REQ_SET_FEATURE - cnf\n");
+		break;
+	case USB_REQ_SET_ADDRESS:
+		oz_trace("USB_REQ_SET_ADDRESS - cnf\n");
+		break;
+	case USB_REQ_GET_DESCRIPTOR:
+		oz_trace("USB_REQ_GET_DESCRIPTOR - cnf\n");
+		break;
+	case USB_REQ_SET_DESCRIPTOR:
+		oz_trace("USB_REQ_SET_DESCRIPTOR - cnf\n");
+		break;
+	case USB_REQ_GET_CONFIGURATION:
+		oz_trace("USB_REQ_GET_CONFIGURATION - cnf\n");
+		break;
+	case USB_REQ_SET_CONFIGURATION:
+		oz_trace("USB_REQ_SET_CONFIGURATION - cnf\n");
+		break;
+	case USB_REQ_GET_INTERFACE:
+		oz_trace("USB_REQ_GET_INTERFACE - cnf\n");
+		break;
+	case USB_REQ_SET_INTERFACE:
+		oz_trace("USB_REQ_SET_INTERFACE - cnf\n");
+		break;
+	case USB_REQ_SYNCH_FRAME:
+		oz_trace("USB_REQ_SYNCH_FRAME - cnf\n");
+		break;
+	}
+}
+#else
+#define oz_display_conf_type(__x)
+#endif /* WANT_TRACE */
+/*------------------------------------------------------------------------------
+ * Context: softirq
+ */
+static void oz_hcd_complete_set_config(struct oz_port *port, struct urb *urb,
+		u8 rcode, u8 config_num)
+{
+	int rc = 0;
+	struct usb_hcd *hcd = port->ozhcd->hcd;
+	if (rcode == 0) {
+		port->config_num = config_num;
+		oz_clean_endpoints_for_config(hcd, port);
+		if (oz_build_endpoints_for_config(hcd, port,
+			&urb->dev->config[port->config_num-1], GFP_ATOMIC)) {
+			rc = -ENOMEM;
+		}
+	} else {
+		rc = -ENOMEM;
+	}
+	oz_complete_urb(hcd, urb, rc, 0);
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq
+ */
+static void oz_hcd_complete_set_interface(struct oz_port *port, struct urb *urb,
+		u8 rcode, u8 if_num, u8 alt)
+{
+	struct usb_hcd *hcd = port->ozhcd->hcd;
+	int rc = 0;
+	if (rcode == 0) {
+		struct usb_host_config *config;
+		struct usb_host_interface *intf;
+		oz_trace("Set interface %d alt %d\n", if_num, alt);
+		oz_clean_endpoints_for_interface(hcd, port, if_num);
+		config = &urb->dev->config[port->config_num-1];
+		intf = &config->intf_cache[if_num]->altsetting[alt];
+		if (oz_build_endpoints_for_interface(hcd, port, intf,
+			GFP_ATOMIC))
+			rc = -ENOMEM;
+		else
+			port->iface[if_num].alt = alt;
+	} else {
+		rc = -ENOMEM;
+	}
+	oz_complete_urb(hcd, urb, rc, 0);
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq
+ */
+void oz_hcd_control_cnf(void *hport, u8 req_id, u8 rcode, u8 *data,
+	int data_len)
+{
+	struct oz_port *port = (struct oz_port *)hport;
+	struct urb *urb;
+	struct usb_ctrlrequest *setup;
+	struct usb_hcd *hcd = port->ozhcd->hcd;
+	unsigned windex;
+	unsigned wvalue;
+
+	oz_event_log(OZ_EVT_CTRL_CNF, 0, req_id, 0, rcode);
+	oz_trace("oz_hcd_control_cnf rcode=%u len=%d\n", rcode, data_len);
+	urb = oz_find_urb_by_id(port, 0, req_id);
+	if (!urb) {
+		oz_trace("URB not found\n");
+		return;
+	}
+	setup = (struct usb_ctrlrequest *)urb->setup_packet;
+	windex = le16_to_cpu(setup->wIndex);
+	wvalue = le16_to_cpu(setup->wValue);
+	if ((setup->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD) {
+		/* Standard requests */
+		oz_display_conf_type(setup->bRequest);
+		switch (setup->bRequest) {
+		case USB_REQ_SET_CONFIGURATION:
+			oz_hcd_complete_set_config(port, urb, rcode,
+				(u8)wvalue);
+			break;
+		case USB_REQ_SET_INTERFACE:
+			oz_hcd_complete_set_interface(port, urb, rcode,
+				(u8)windex, (u8)wvalue);
+			break;
+		default:
+			oz_complete_urb(hcd, urb, 0, 0);
+		}
+
+	} else {
+		int copy_len;
+		oz_trace("VENDOR-CLASS - cnf\n");
+		if (data_len <= urb->transfer_buffer_length)
+			copy_len = data_len;
+		else
+			copy_len = urb->transfer_buffer_length;
+		if (copy_len)
+			memcpy(urb->transfer_buffer, data, copy_len);
+		urb->actual_length = copy_len;
+		oz_complete_urb(hcd, urb, 0, 0);
+	}
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq-serialized
+ */
+static int oz_hcd_buffer_data(struct oz_endpoint *ep, u8 *data, int data_len)
+{
+	int space;
+	int copy_len;
+	if (!ep->buffer)
+		return -1;
+	space = ep->out_ix-ep->in_ix-1;
+	if (space < 0)
+		space += ep->buffer_size;
+	if (space < (data_len+1)) {
+		oz_trace("Buffer full\n");
+		return -1;
+	}
+	ep->buffer[ep->in_ix] = (u8)data_len;
+	if (++ep->in_ix == ep->buffer_size)
+		ep->in_ix = 0;
+	copy_len = ep->buffer_size - ep->in_ix;
+	if (copy_len > data_len)
+		copy_len = data_len;
+	memcpy(&ep->buffer[ep->in_ix], data, copy_len);
+
+	if (copy_len < data_len) {
+		memcpy(ep->buffer, data+copy_len, data_len-copy_len);
+		ep->in_ix = data_len-copy_len;
+	} else {
+		ep->in_ix += copy_len;
+	}
+	if (ep->in_ix == ep->buffer_size)
+		ep->in_ix = 0;
+	ep->buffered_units++;
+	return 0;
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq-serialized
+ */
+void oz_hcd_data_ind(void *hport, u8 endpoint, u8 *data, int data_len)
+{
+	struct oz_port *port = (struct oz_port *)hport;
+	struct oz_endpoint *ep;
+	struct oz_hcd *ozhcd = port->ozhcd;
+	spin_lock_bh(&ozhcd->hcd_lock);
+	ep = port->in_ep[endpoint & USB_ENDPOINT_NUMBER_MASK];
+	if (ep == 0)
+		goto done;
+	switch (ep->attrib & USB_ENDPOINT_XFERTYPE_MASK) {
+	case USB_ENDPOINT_XFER_INT:
+	case USB_ENDPOINT_XFER_BULK:
+		if (!list_empty(&ep->urb_list)) {
+			struct oz_urb_link *urbl =
+				list_first_entry(&ep->urb_list,
+					struct oz_urb_link, link);
+			struct urb *urb;
+			int copy_len;
+			list_del_init(&urbl->link);
+			spin_unlock_bh(&ozhcd->hcd_lock);
+			urb = urbl->urb;
+			oz_free_urb_link(urbl);
+			if (data_len <= urb->transfer_buffer_length)
+				copy_len = data_len;
+			else
+				copy_len = urb->transfer_buffer_length;
+			memcpy(urb->transfer_buffer, data, copy_len);
+			urb->actual_length = copy_len;
+			oz_complete_urb(port->ozhcd->hcd, urb, 0, 0);
+			return;
+		}
+		break;
+	case USB_ENDPOINT_XFER_ISOC:
+		oz_hcd_buffer_data(ep, data, data_len);
+		break;
+	}
+done:
+	spin_unlock_bh(&ozhcd->hcd_lock);
+}
+/*------------------------------------------------------------------------------
+ * Context: unknown
+ */
+static inline int oz_usb_get_frame_number(void)
+{
+	return jiffies_to_msecs(get_jiffies_64());
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq
+ */
+int oz_hcd_heartbeat(void *hport)
+{
+	int rc = 0;
+	struct oz_port *port = (struct oz_port *)hport;
+	struct oz_hcd *ozhcd = port->ozhcd;
+	struct oz_urb_link *urbl;
+	struct list_head xfr_list;
+	struct list_head *e;
+	struct list_head *n;
+	struct urb *urb;
+	struct oz_endpoint *ep;
+	unsigned long now = jiffies;
+	INIT_LIST_HEAD(&xfr_list);
+	/* Check the OUT isoc endpoints to see if any URB data can be sent.
+	 */
+	spin_lock_bh(&ozhcd->hcd_lock);
+	list_for_each(e, &port->isoc_out_ep) {
+		ep = ep_from_link(e);
+		if (ep->credit < 0)
+			continue;
+		ep->credit += (now - ep->last_jiffies);
+		if (ep->credit > ep->credit_ceiling)
+			ep->credit = ep->credit_ceiling;
+		oz_event_log(OZ_EVT_EP_CREDIT, ep->ep_num, 0, 0, ep->credit);
+		ep->last_jiffies = now;
+		while (ep->credit && !list_empty(&ep->urb_list)) {
+			urbl = list_first_entry(&ep->urb_list,
+				struct oz_urb_link, link);
+			urb = urbl->urb;
+			if (ep->credit < urb->number_of_packets)
+				break;
+			ep->credit -= urb->number_of_packets;
+			oz_event_log(OZ_EVT_EP_CREDIT, ep->ep_num, 0, 0,
+				ep->credit);
+			list_del(&urbl->link);
+			list_add_tail(&urbl->link, &xfr_list);
+		}
+	}
+	spin_unlock_bh(&ozhcd->hcd_lock);
+	/* Send to PD and complete URBs.
+	 */
+	list_for_each_safe(e, n, &xfr_list) {
+		unsigned long t;
+		urbl = container_of(e, struct oz_urb_link, link);
+		urb = urbl->urb;
+		t = urbl->submit_jiffies;
+		list_del_init(e);
+		urb->error_count = 0;
+		urb->start_frame = oz_usb_get_frame_number();
+		oz_usb_send_isoc(port->hpd, urbl->ep_num, urb);
+		oz_free_urb_link(urbl);
+		oz_complete_urb(port->ozhcd->hcd, urb, 0, t);
+	}
+	/* Check the IN isoc endpoints to see if any URBs can be completed.
+	 */
+	spin_lock_bh(&ozhcd->hcd_lock);
+	list_for_each(e, &port->isoc_in_ep) {
+		struct oz_endpoint *ep = ep_from_link(e);
+		if (ep->flags & OZ_F_EP_BUFFERING) {
+			if (ep->buffered_units * OZ_IN_BUFFERING_UNITS) {
+				ep->flags &= ~OZ_F_EP_BUFFERING;
+				ep->credit = 0;
+				oz_event_log(OZ_EVT_EP_CREDIT,
+					ep->ep_num | USB_DIR_IN,
+					0, 0, ep->credit);
+				ep->last_jiffies = now;
+				ep->start_frame = 0;
+				oz_event_log(OZ_EVT_EP_BUFFERING,
+					ep->ep_num | US