/*

 * Event channel port operations.

 *

 * Copyright (c) 2003-2006, K A Fraser.

 *

 * This source code is licensed under the GNU General Public License,

 * Version 2 or later.  See the file COPYING for more details.

 */

#include <xen/init.h>

#include <xen/lib.h>

#include <xen/errno.h>

#include <xen/sched.h>

#include <xen/event.h>

static void evtchn_2l_set_pending(struct vcpu *v, struct evtchn *evtchn)

{

    struct domain *d = v->domain;

    unsigned int port = evtchn->port;

    /*

     * The following bit operations must happen in strict order.

     * NB. On x86, the atomic bit operations also act as memory barriers.

     * There is therefore sufficiently strict ordering for this architecture --

     * others may require explicit memory barriers.

     */

    if ( test_and_set_bit(port, &shared_info(d, evtchn_pending)) )

        return;

    if ( !test_bit        (port, &shared_info(d, evtchn_mask)) &&

         !test_and_set_bit(port / BITS_PER_EVTCHN_WORD(d),

                           &vcpu_info(v, evtchn_pending_sel)) )

    {

        vcpu_mark_events_pending(v);

    }

    evtchn_check_pollers(d, port);

}

static void evtchn_2l_clear_pending(struct domain *d, struct evtchn *evtchn)

{

    clear_bit(evtchn->port, &shared_info(d, evtchn_pending));

}

static void evtchn_2l_unmask(struct domain *d, struct evtchn *evtchn)

{

    struct vcpu *v = d->vcpu[evtchn->notify_vcpu_id];

    unsigned int port = evtchn->port;

    /*

     * These operations must happen in strict order. Based on

     * evtchn_2l_set_pending() above.

     */

    if ( test_and_clear_bit(port, &shared_info(d, evtchn_mask)) &&

         test_bit          (port, &shared_info(d, evtchn_pending)) &&

         !test_and_set_bit (port / BITS_PER_EVTCHN_WORD(d),

                            &vcpu_info(v, evtchn_pending_sel)) )

    {

        vcpu_mark_events_pending(v);

    }

}

static bool evtchn_2l_is_pending(const struct domain *d, evtchn_port_t port)

{

    unsigned int max_ports = BITS_PER_EVTCHN_WORD(d) * BITS_PER_EVTCHN_WORD(d);

    ASSERT(port < max_ports);

    return port < max_ports && test_bit(port, &shared_info(d, evtchn_pending));

}

static bool evtchn_2l_is_masked(const struct domain *d, evtchn_port_t port)

{

    unsigned int max_ports = BITS_PER_EVTCHN_WORD(d) * BITS_PER_EVTCHN_WORD(d);

    ASSERT(port < max_ports);

    return port >= max_ports || test_bit(port, &shared_info(d, evtchn_mask));

}

static void evtchn_2l_print_state(struct domain *d,

                                  const struct evtchn *evtchn)

{

    struct vcpu *v = d->vcpu[evtchn->notify_vcpu_id];

    printk("%d", !!test_bit(evtchn->port / BITS_PER_EVTCHN_WORD(d),

                            &vcpu_info(v, evtchn_pending_sel)));

}

static const struct evtchn_port_ops evtchn_port_ops_2l =

{

    .set_pending   = evtchn_2l_set_pending,

    .clear_pending = evtchn_2l_clear_pending,

    .unmask        = evtchn_2l_unmask,

    .is_pending    = evtchn_2l_is_pending,

    .is_masked     = evtchn_2l_is_masked,

    .print_state   = evtchn_2l_print_state,

};

void evtchn_2l_init(struct domain *d)

{

    d->evtchn_port_ops = &evtchn_port_ops_2l;

    d->max_evtchns = BITS_PER_EVTCHN_WORD(d) * BITS_PER_EVTCHN_WORD(d);

}

/*

 * Local variables:

 * mode: C

 * c-file-style: "BSD"

 * c-basic-offset: 4

 * tab-width: 4

 * indent-tabs-mode: nil

 * End:

 */