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/*
* Copyright (C) 2006-2007 XenSource Ltd.
* Copyright (C) 2008 Citrix Ltd.
* Author Vincent Hanquez <vincent.hanquez@eu.citrix.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; version 2.1 only. with the special
* exception on linking described in file LICENSE.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <xenctrl.h>
#include <xen/io/xs_wire.h>
#include <caml/mlvalues.h>
#include <caml/memory.h>
#include <caml/alloc.h>
#include <caml/custom.h>
#include <caml/fail.h>
#include <caml/callback.h>
#include "mmap_stubs.h"
#define GET_C_STRUCT(a) ((struct mmap_interface *) a)
static int xs_ring_read(struct mmap_interface *interface,
char *buffer, int len)
{
struct xenstore_domain_interface *intf = interface->addr;
XENSTORE_RING_IDX cons, prod; /* offsets only */
int to_read;
cons = *(volatile uint32*)&intf->req_cons;
prod = *(volatile uint32*)&intf->req_prod;
xen_mb();
if (prod == cons)
return 0;
cons = MASK_XENSTORE_IDX(cons);
prod = MASK_XENSTORE_IDX(prod);
if (prod > cons)
to_read = prod - cons;
else
to_read = XENSTORE_RING_SIZE - cons;
if (to_read < len)
len = to_read;
memcpy(buffer, intf->req + cons, len);
xen_mb();
intf->req_cons += len;
return len;
}
static int xs_ring_write(struct mmap_interface *interface,
char *buffer, int len)
{
struct xenstore_domain_interface *intf = interface->addr;
XENSTORE_RING_IDX cons, prod;
int can_write;
cons = *(volatile uint32*)&intf->rsp_cons;
prod = *(volatile uint32*)&intf->rsp_prod;
xen_mb();
if ( (prod - cons) >= XENSTORE_RING_SIZE )
return 0;
if (MASK_XENSTORE_IDX(prod) >= MASK_XENSTORE_IDX(cons))
can_write = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(prod);
else
can_write = MASK_XENSTORE_IDX(cons) - MASK_XENSTORE_IDX(prod);
if (can_write < len)
len = can_write;
memcpy(intf->rsp + MASK_XENSTORE_IDX(prod), buffer, len);
xen_mb();
intf->rsp_prod += len;
return len;
}
CAMLprim value ml_interface_read(value interface, value buffer, value len)
{
CAMLparam3(interface, buffer, len);
CAMLlocal1(result);
int res;
res = xs_ring_read(GET_C_STRUCT(interface),
String_val(buffer), Int_val(len));
if (res == -1)
caml_failwith("huh");
result = Val_int(res);
CAMLreturn(result);
}
CAMLprim value ml_interface_write(value interface, value buffer, value len)
{
CAMLparam3(interface, buffer, len);
CAMLlocal1(result);
int res;
res = xs_ring_write(GET_C_STRUCT(interface),
String_val(buffer), Int_val(len));
result = Val_int(res);
CAMLreturn(result);
}
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