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/* A pager interface for raw mach devices.
Copyright (C) 1995 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
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, or (at
your option) any later version.
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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include <hurd.h>
#include <hurd/pager.h>
#include <device/device.h>
#include <assert.h>
#include "dev.h"
#include "ptypes.h"
/* ---------------------------------------------------------------- */
/* Pager library callbacks; see <hurd/pager.h> for more info. */
/* This will be the type used in calls to allocate_port by the pager system.
*/
int pager_port_type = PT_MEMOBJ;
/* For pager PAGER, read one page from offset PAGE. Set *BUF to be the
address of the page, and set *WRITE_LOCK if the page must be provided
read-only. The only permissable error returns are EIO, EDQUOT, and
ENOSPC. */
error_t
pager_read_page(struct user_pager_info *upi,
vm_offset_t page, vm_address_t *buf, int *writelock)
{
error_t err;
int read; /* bytes actually read */
int want = vm_page_size; /* bytes we want to read */
struct dev *dev = (struct dev *)upi;
if (page + want > dev->size)
/* Read a partial page if necessary to avoid reading off the end. */
want = dev->size - page;
err = device_read(dev->port, 0, page / dev->dev_block_size, want,
(io_buf_ptr_t *)buf, &read);
#ifdef MSG
if (debug)
{
mutex_lock(&debug_lock);
fprintf(debug, "device_read(%d, %d) [pager] => %s, %s, %d\n",
page / dev->dev_block_size, want,
strerror(err), err ? "-" : brep(*buf, read), read);
mutex_unlock(&debug_lock);
}
#endif
if (!err && want < vm_page_size)
/* Zero anything we didn't read. Allocation only happens in page-size
multiples, so we know we can write there. */
bzero((char *)*buf + want, vm_page_size - want);
*writelock = (dev->flags & DEV_READONLY);
if (err || read < want)
return EIO;
else
return 0;
}
/* For pager PAGER, synchronously write one page from BUF to offset PAGE. In
addition, vm_deallocate (or equivalent) BUF. The only permissable error
returns are EIO, EDQUOT, and ENOSPC. */
error_t
pager_write_page(struct user_pager_info *upi,
vm_offset_t page, vm_address_t buf)
{
struct dev *dev = (struct dev *)upi;
if (dev->flags & DEV_READONLY)
return EROFS;
else
{
error_t err;
int written;
int want = vm_page_size;
if (page + want > dev->size)
/* Write a partial page if necessary to avoid reading off the end. */
want = dev->size - page;
err = device_write(dev->port, 0, page / dev->dev_block_size,
(io_buf_ptr_t)buf, want, &written);
#ifdef MSG
if (debug)
{
mutex_lock(&debug_lock);
fprintf(debug, "device_write(%d, %s, %d) [pager] => %s, %d\n",
page / dev->dev_block_size,
brep(buf, vm_page_size), vm_page_size,
strerror(err), written);
mutex_unlock(&debug_lock);
}
#endif
vm_deallocate(mach_task_self(), buf, vm_page_size);
if (err || written < want)
return EIO;
else
return 0;
}
}
/* A page should be made writable. */
error_t
pager_unlock_page(struct user_pager_info *upi, vm_offset_t address)
{
struct dev *dev = (struct dev *)upi;
if (dev->flags & DEV_READONLY)
return EROFS;
else
return 0;
}
/* The user must define this function. It should report back (in
*OFFSET and *SIZE the minimum valid address the pager will accept
and the size of the object. */
error_t
pager_report_extent(struct user_pager_info *upi,
vm_address_t *offset, vm_size_t *size)
{
*offset = 0;
*size = ((struct dev *)upi)->size;
return 0;
}
/* This is called when a pager is being deallocated after all extant send
rights have been destroyed. */
void
pager_clear_user_data(struct user_pager_info *upi)
{
}
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