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/******************************************************************************
* xenbus_comms.c
*
* Low level code to talks to Xen Store: ringbuffer and event channel.
*
* Copyright (C) 2005 Rusty Russell, IBM Corporation
*
* This file may be distributed separately from the Linux kernel, or
* incorporated into other software packages, subject to the following license:
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this source file (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy, modify,
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/time.h>
#include <sys/errno.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/syslog.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <machine/xen/xen-os.h>
#include <machine/xen/hypervisor.h>
#include <machine/xen/evtchn.h>
#include <machine/xen/xen_intr.h>
#include <xen/xenbus/xenbus_comms.h>
#include <xen/interface/io/xs_wire.h>
static int xenbus_irq;
extern void xenbus_probe(void *);
extern int xenstored_ready;
#if 0
static DECLARE_WORK(probe_work, xenbus_probe, NULL);
#endif
int xb_wait;
extern char *xen_store;
#define wake_up wakeup
#define xb_waitq xb_wait
#define pr_debug(a,b,c)
static inline struct xenstore_domain_interface *xenstore_domain_interface(void)
{
return (struct xenstore_domain_interface *)xen_store;
}
static void
wake_waiting(void * arg __attribute__((unused)))
{
#if 0
if (unlikely(xenstored_ready == 0)) {
xenstored_ready = 1;
schedule_work(&probe_work);
}
#endif
wakeup(&xb_wait);
}
static int check_indexes(XENSTORE_RING_IDX cons, XENSTORE_RING_IDX prod)
{
return ((prod - cons) <= XENSTORE_RING_SIZE);
}
static void *get_output_chunk(XENSTORE_RING_IDX cons,
XENSTORE_RING_IDX prod,
char *buf, uint32_t *len)
{
*len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(prod);
if ((XENSTORE_RING_SIZE - (prod - cons)) < *len)
*len = XENSTORE_RING_SIZE - (prod - cons);
return buf + MASK_XENSTORE_IDX(prod);
}
static const void *get_input_chunk(XENSTORE_RING_IDX cons,
XENSTORE_RING_IDX prod,
const char *buf, uint32_t *len)
{
*len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(cons);
if ((prod - cons) < *len)
*len = prod - cons;
return buf + MASK_XENSTORE_IDX(cons);
}
int xb_write(const void *tdata, unsigned len)
{
struct xenstore_domain_interface *intf = xenstore_domain_interface();
XENSTORE_RING_IDX cons, prod;
const char *data = (const char *)tdata;
while (len != 0) {
void *dst;
unsigned int avail;
wait_event_interruptible(&xb_waitq,
(intf->req_prod - intf->req_cons) !=
XENSTORE_RING_SIZE);
/* Read indexes, then verify. */
cons = intf->req_cons;
prod = intf->req_prod;
mb();
if (!check_indexes(cons, prod)) {
intf->req_cons = intf->req_prod = 0;
return -EIO;
}
dst = get_output_chunk(cons, prod, intf->req, &avail);
if (avail == 0)
continue;
if (avail > len)
avail = len;
mb();
memcpy(dst, data, avail);
data += avail;
len -= avail;
/* Other side must not see new header until data is there. */
wmb();
intf->req_prod += avail;
/* This implies mb() before other side sees interrupt. */
notify_remote_via_evtchn(xen_start_info->store_evtchn);
}
return 0;
}
#ifdef notyet
int xb_data_to_read(void)
{
struct xenstore_domain_interface *intf = xen_store_interface;
return (intf->rsp_cons != intf->rsp_prod);
}
int xb_wait_for_data_to_read(void)
{
return wait_event_interruptible(xb_waitq, xb_data_to_read());
}
#endif
int xb_read(void *tdata, unsigned len)
{
struct xenstore_domain_interface *intf = xenstore_domain_interface();
XENSTORE_RING_IDX cons, prod;
char *data = (char *)tdata;
while (len != 0) {
unsigned int avail;
const char *src;
wait_event_interruptible(&xb_waitq,
intf->rsp_cons != intf->rsp_prod);
/* Read indexes, then verify. */
cons = intf->rsp_cons;
prod = intf->rsp_prod;
if (!check_indexes(cons, prod)) {
intf->rsp_cons = intf->rsp_prod = 0;
return -EIO;
}
src = get_input_chunk(cons, prod, intf->rsp, &avail);
if (avail == 0)
continue;
if (avail > len)
avail = len;
/* We must read header before we read data. */
rmb();
memcpy(data, src, avail);
data += avail;
len -= avail;
/* Other side must not see free space until we've copied out */
mb();
intf->rsp_cons += avail;
pr_debug("Finished read of %i bytes (%i to go)\n", avail, len);
/* Implies mb(): they will see new header. */
notify_remote_via_evtchn(xen_start_info->store_evtchn);
}
return 0;
}
/* Set up interrupt handler off store event channel. */
int xb_init_comms(void)
{
struct xenstore_domain_interface *intf = xenstore_domain_interface();
int err;
if (intf->rsp_prod != intf->rsp_cons) {
log(LOG_WARNING, "XENBUS response ring is not quiescent "
"(%08x:%08x): fixing up\n",
intf->rsp_cons, intf->rsp_prod);
intf->rsp_cons = intf->rsp_prod;
}
if (xenbus_irq)
unbind_from_irqhandler(xenbus_irq, &xb_waitq);
err = bind_caller_port_to_irqhandler(
xen_start_info->store_evtchn,
"xenbus", wake_waiting, NULL, INTR_TYPE_NET, NULL);
if (err <= 0) {
log(LOG_WARNING, "XENBUS request irq failed %i\n", err);
return err;
}
xenbus_irq = err;
return 0;
}
/*
* Local variables:
* c-file-style: "bsd"
* indent-tabs-mode: t
* c-indent-level: 4
* c-basic-offset: 8
* tab-width: 4
* End:
*/
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