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/* Copyright (C) 2004 David Decotigny
Copyright (C) 2000 The KOS Team
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
of the License, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.
*/
#ifndef _SOS_PHYSMEM_H_
#define _SOS_PHYSMEM_H_
/**
* @file physmem.h
*
* Physical pages of memory
*/
#include <sos/errno.h>
#include <sos/types.h>
#include <sos/macros.h>
/** The size of a physical page (arch-dependent) */
#define SOS_PAGE_SIZE (4*1024)
/** The corresponding shift */
#define SOS_PAGE_SHIFT 12 /* 4 kB = 2^12 B */
/** The corresponding mask */
#define SOS_PAGE_MASK ((1<<12) - 1)
#define SOS_PAGE_ALIGN_INF(val) \
SOS_ALIGN_INF((val), SOS_PAGE_SIZE)
#define SOS_PAGE_ALIGN_SUP(val) \
SOS_ALIGN_SUP((val), SOS_PAGE_SIZE)
#define SOS_IS_PAGE_ALIGNED(val) \
SOS_IS_ALIGNED((val), SOS_PAGE_SIZE)
/**
* This is the reserved physical interval for the x86 video memory and
* BIOS area. In physmem.c, we have to mark this area as "used" in
* order to prevent from allocating it. And in paging.c, we'd better
* map it in virtual space if we really want to be able to print to
* the screen (for debugging purpose, at least): for this, the
* simplest is to identity-map this area in virtual space (note
* however that this mapping could also be non-identical).
*/
#define BIOS_N_VIDEO_START 0xa0000
#define BIOS_N_VIDEO_END 0x100000
/**
* Initialize the physical memory subsystem, for the physical area [0,
* ram_size). This routine takes into account the BIOS and video
* areas, to prevent them from future allocations.
*
* @param ram_size The size of the RAM that will be managed by this subsystem
*
* @param kernel_core_base The lowest address for which the kernel
* assumes identity mapping (ie virtual address == physical address)
* will be stored here
*
* @param kernel_core_top The top address for which the kernel
* assumes identity mapping (ie virtual address == physical address)
* will be stored here
*/
sos_ret_t sos_physmem_subsystem_setup(sos_size_t ram_size,
/* out */sos_paddr_t *kernel_core_base,
/* out */sos_paddr_t *kernel_core_top);
/**
* Retrieve the total number of pages, and the number of free pages
*/
sos_ret_t sos_physmem_get_state(/* out */sos_count_t *total_ppages,
/* out */sos_count_t *used_ppages);
/**
* Get a free page.
*
* @return The (physical) address of the (physical) page allocated, or
* NULL when none currently available.
*
* @param can_block TRUE if the function is allowed to block
* @note The page returned has a reference count equal to 1.
*/
sos_paddr_t sos_physmem_ref_physpage_new(sos_bool_t can_block);
/**
* Increment the reference count of a given physical page. Useful for
* VM code which tries to map a precise physical address.
*
* @param ppage_paddr Physical address of the page (MUST be page-aligned)
*
* @return TRUE when the page was previously in use, FALSE when the
* page was previously in the free list, <0 when the page address is
* invalid.
*/
sos_ret_t sos_physmem_ref_physpage_at(sos_paddr_t ppage_paddr);
/**
* Decrement the reference count of the given physical page. When this
* reference count reaches 0, the page is marked free, ie is available
* for future sos_physmem_get_physpage()
*
* @param ppage_paddr Physical address of the page (MUST be page-aligned)
*
* @return FALSE when the page is still in use, TRUE when the page is now
* unreferenced, <0 when the page address is invalid
*/
sos_ret_t sos_physmem_unref_physpage(sos_paddr_t ppage_paddr);
#include <sos/kmem_vmm.h>
/**
* Return the kernel memory allocation range associated with the given
* physical page, or NULL when page has no associated range
*
* @param ppage_paddr Physical address of the page (MUST be page-aligned)
*/
struct sos_kmem_range* sos_physmem_get_kmem_range(sos_paddr_t ppage_paddr);
/**
* Set the kernel memory allocation range associated to the given
* physical page.
*
* @param ppage_paddr Physical address of the page (MUST be page-aligned)
*
* @return error if page is invalid
*/
sos_ret_t sos_physmem_set_kmem_range(sos_paddr_t ppage_paddr,
struct sos_kmem_range *range);
#endif /* _SOS_PHYSMEM_H_ */
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