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/*
 * Copyright (C) 2006 Jakub Jermar
 * Copyright (C) 2006 Jakub Vana
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <arch/mm/page.h>
#include <genarch/mm/page_ht.h>
#include <mm/asid.h>
#include <arch/types.h>
#include <print.h>
#include <mm/page.h>
#include <mm/frame.h>
#include <config.h>
#include <panic.h>
#include <arch/asm.h>
#include <arch/barrier.h>
#include <memstr.h>

/** Initialize VHPT and region registers. */
static void set_vhpt_environment(void)
{
    region_register rr;
    pta_register pta;   
    int i;
    
    /*
     * First set up kernel region register.
     */
    rr.word = rr_read(VRN_KERNEL);
    rr.map.ve = 0;                  /* disable VHPT walker */
    rr.map.ps = PAGE_WIDTH;
    rr.map.rid = ASID_KERNEL;
    rr_write(VRN_KERNEL, rr.word);
    srlz_i();
    srlz_d();
    
    /*
     * And invalidate the rest of region register.
     */
    for(i = 0; i < REGION_REGISTERS; i++) {
        /* skip kernel rr */
        if (i == VRN_KERNEL)
            continue;
    
        rr.word == rr_read(i);
        rr.map.ve = 0;      /* disable VHPT walker */
        rr.map.rid = ASID_INVALID;
        rr_write(i, rr.word);
        srlz_i();
        srlz_d();
    }

    /*
     * Allocate VHPT and invalidate all its entries.
     */
    page_ht = (pte_t *) frame_alloc(FRAME_KA, VHPT_WIDTH - FRAME_WIDTH, NULL);
    memsetb((__address) page_ht, VHPT_SIZE, 0);
    ht_invalidate_all();    
    
    /*
     * Set up PTA register.
     */
    pta.word = pta_read();
    pta.map.ve = 0;                   /* disable VHPT walker */
    pta.map.vf = 1;                   /* large entry format */
    pta.map.size = VHPT_WIDTH;
    pta.map.base = (__address) page_ht;
    pta_write(pta.word);
    srlz_i();
    srlz_d();
}

/** Initialize ia64 virtual address translation subsystem. */
void page_arch_init(void)
{
    page_operations = &page_ht_operations;
    pk_disable();
    set_vhpt_environment();
}

/** Calculate address of collision chain from VPN and ASID.
 *
 * This is rather non-trivial function.
 * First, it has to translate ASID to RID.
 * This is achieved by taking VRN bits of
 * page into account.
 * Second, it must preserve the region register
 * it writes the RID to.
 *
 * @param page Address of virtual page including VRN bits.
 * @param asid Address space identifier.
 *
 * @return Head of VHPT collision chain for page and asid.
 */
pte_t *vhpt_hash(__address page, asid_t asid)
{
    region_register rr_save, rr;
    pte_t *t;

    rr_save.word = rr_read(VRN_WORK);
    rr.word = rr_save.word;
    if ((page >> VRN_SHIFT) != VRN_KERNEL)
        rr.map.rid = (asid * RIDS_PER_ASID) + (page >> VRN_SHIFT);
    else
        rr.map.rid = ASID_KERNEL;
    rr_write(VRN_WORK, rr.word);
    srlz_i();
    t = (pte_t *) thash((VRN_WORK << VRN_SHIFT) | (~(VRN_MASK) & page));
    rr_write(VRN_WORK, rr_save.word);
    srlz_i();
    srlz_d();

    return t;
}