/*
 * "Cell Reference Set" HTAB support.
 *
 * (C) Copyright 2006-2007 TOSHIBA CORPORATION
 *
 * This code is based on arch/powerpc/platforms/pseries/lpar.c:
 *  Copyright (C) 2001 Todd Inglett, IBM Corporation
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#undef DEBUG_LOW

#include <linux/kernel.h>
#include <linux/spinlock.h>

#include <asm/mmu.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/machdep.h>
#include <asm/udbg.h>

#include "beat_wrapper.h"

#ifdef DEBUG_LOW
#define DBG_LOW(fmt...) do { udbg_printf(fmt); } while(0)
#else
#define DBG_LOW(fmt...) do { } while(0)
#endif

static DEFINE_SPINLOCK(beat_htab_lock);

static inline unsigned int beat_read_mask(unsigned hpte_group)
{
	unsigned long hpte_v[5];
	unsigned long rmask = 0;

	beat_read_htab_entries(0, hpte_group + 0, hpte_v);
	if (!(hpte_v[0] & HPTE_V_BOLTED))
		rmask |= 0x8000;
	if (!(hpte_v[1] & HPTE_V_BOLTED))
		rmask |= 0x4000;
	if (!(hpte_v[2] & HPTE_V_BOLTED))
		rmask |= 0x2000;
	if (!(hpte_v[3] & HPTE_V_BOLTED))
		rmask |= 0x1000;
	beat_read_htab_entries(0, hpte_group + 4, hpte_v);
	if (!(hpte_v[0] & HPTE_V_BOLTED))
		rmask |= 0x0800;
	if (!(hpte_v[1] & HPTE_V_BOLTED))
		rmask |= 0x0400;
	if (!(hpte_v[2] & HPTE_V_BOLTED))
		rmask |= 0x0200;
	if (!(hpte_v[3] & HPTE_V_BOLTED))
		rmask |= 0x0100;
	hpte_group = ~hpte_group & (htab_hash_mask * HPTES_PER_GROUP);
	beat_read_htab_entries(0, hpte_group + 0, hpte_v);
	if (!(hpte_v[0] & HPTE_V_BOLTED))
		rmask |= 0x80;
	if (!(hpte_v[1] & HPTE_V_BOLTED))
		rmask |= 0x40;
	if (!(hpte_v[2] & HPTE_V_BOLTED))
		rmask |= 0x20;
	if (!(hpte_v[3] & HPTE_V_BOLTED))
		rmask |= 0x10;
	beat_read_htab_entries(0, hpte_group + 4, hpte_v);
	if (!(hpte_v[0] & HPTE_V_BOLTED))
		rmask |= 0x08;
	if (!(hpte_v[1] & HPTE_V_BOLTED))
		rmask |= 0x04;
	if (!(hpte_v[2] & HPTE_V_BOLTED))
		rmask |= 0x02;
	if (!(hpte_v[3] & HPTE_V_BOLTED))
		rmask |= 0x01;
	return rmask;
}

static long beat_lpar_hpte_insert(unsigned long hpte_group,
				  unsigned long va, unsigned long pa,
				  unsigned long rflags, unsigned long vflags,
				  int psize)
{
	unsigned long lpar_rc;
	unsigned long slot;
	unsigned long hpte_v, hpte_r;

	/* same as iseries */
	if (vflags & HPTE_V_SECONDARY)
		return -1;

	if (!(vflags & HPTE_V_BOLTED))
		DBG_LOW("hpte_insert(group=%lx, va=%016lx, pa=%016lx, "
			"rflags=%lx, vflags=%lx, psize=%d)\n",
		hpte_group, va, pa, rflags, vflags, psize);

	hpte_v = hpte_encode_v(va, psize) | vflags | HPTE_V_VALID;
	hpte_r = hpte_encode_r(pa, psize) | rflags;

	if (!(vflags & HPTE_V_BOLTED))
		DBG_LOW(" hpte_v=%016lx, hpte_r=%016lx\n", hpte_v, hpte_r);

	if (rflags & (_PAGE_GUARDED|_PAGE_NO_CACHE))
		hpte_r &= ~_PAGE_COHERENT;

	spin_lock(&beat_htab_lock);
	if ((lpar_rc = beat_read_mask(hpte_group)) == 0) {
		if (!(vflags & HPTE_V_BOLTED))
			DBG_LOW(" full\n");
		spin_unlock(&beat_htab_lock);
		return -1;
	}

	lpar_rc = beat_insert_htab_entry(0, hpte_group, lpar_rc << 48,
		hpte_v, hpte_r, &slot);
	spin_unlock(&beat_htab_lock);

	/*
	 * Since we try and ioremap PHBs we don't own, the pte insert
	 * will fail. However we must catch the failure in hash_page
	 * or we will loop forever, so return -2 in this case.
	 */
	if (unlikely(lpar_rc != 0)) {
		if (!(vflags & HPTE_V_BOLTED))
			DBG_LOW(" lpar err %lx\n", lpar_rc);
		return -2;
	}
	if (!(vflags & HPTE_V_BOLTED))
		DBG_LOW(" -> slot: %lx\n", slot);

	/* We have to pass down the secondary bucket bit here as well */
	return (slot ^ hpte_group) & 15;
}

static long beat_lpar_hpte_remove(unsigned long hpte_group)
{
	DBG_LOW("hpte_remove(group=%lx)\n", hpte_group);
	return -1;
}

static unsigned long beat_lpar_hpte_getword0(unsigned long slot)
{
	unsigned long dword0, dword[5];
	unsigned long lpar_rc;

	lpar_rc = beat_read_htab_entries(0, slot & ~3UL, dword);

	dword0 = dword[slot&3];

	BUG_ON(lpar_rc != 0);

	return dword0;
}

static void beat_lpar_hptab_clear(void)
{
	unsigned long size_bytes = 1UL << ppc64_pft_size;
	unsigned long hpte_count = size_bytes >> 4;
	int i;
	unsigned long dummy0, dummy1;

	/* TODO: Use bulk call */
	for (i = 0; i < hpte_count; i++)
		beat_write_htab_entry(0, i, 0, 0, -1UL, -1UL, &dummy0, &dummy1);
}

/*
 * NOTE: for updatepp ops we are fortunate that the linux "newpp" bits and
 * the low 3 bits of flags happen to line up.  So no transform is needed.
 * We can probably optimize here and assume the high bits of newpp are
 * already zero.  For now I am paranoid.
 */
static long beat_lpar_hpte_updatepp(unsigned long slot,
				    unsigned long newpp,
				    unsigned long va,
				    int psize, int local)
{
	unsigned long lpar_rc;
	unsigned long dummy0, dummy1, want_v;

	want_v = hpte_encode_v(va, psize);

	DBG_LOW("    update: "
		"avpnv=%016lx, slot=%016lx, psize: %d, newpp %016lx ... ",
		want_v & HPTE_V_AVPN, slot, psize, newpp);

	spin_lock(&beat_htab_lock);
	dummy0 = beat_lpar_hpte_getword0(slot);
	if ((dummy0 & ~0x7FUL) != (want_v & ~0x7FUL)) {
		DBG_LOW("not found !\n");
		spin_unlock(&beat_htab_lock);
		return -1;
	}

	lpar_rc = beat_write_htab_entry(0, slot, 0, newpp, 0, 7, &dummy0,
					&dummy1);
	spin_unlock(&beat_htab_lock);
	if (lpar_rc != 0 || dummy0 == 0) {
		DBG_LOW("not found !\n");
		return -1;
	}

	DBG_LOW("ok %lx %lx\n", dummy0, dummy1);

	BUG_ON(lpar_rc != 0);

	return 0;
}

static long beat_lpar_hpte_find(unsigned long va, int psize)
{
	unsigned long hash;
	unsigned long i, j;
	long slot;
	unsigned long want_v, hpte_v;

	hash = hpt_hash(va, mmu_psize_defs[psize].shift);
	want_v = hpte_encode_v(va, psize);

	for (j = 0; j < 2; j++) {
		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
		for (i = 0; i < HPTES_PER_GROUP; i++) {
			hpte_v = beat_lpar_hpte_getword0(slot);

			if (HPTE_V_COMPARE(hpte_v, want_v)
			    && (hpte_v & HPTE_V_VALID)
			    && (!!(hpte_v & HPTE_V_SECONDARY) == j)) {
				/* HPTE matches */
				if (j)
					slot = -slot;
				return slot;
			}
			++slot;
		}
		hash = ~hash;
	}

	return -1;
}

static void beat_lpar_hpte_updateboltedpp(unsigned long newpp,
					  unsigned long ea,
					  int psize)
{
	unsigned long lpar_rc, slot, vsid, va, dummy0, dummy1;

	vsid = get_kernel_vsid(ea);
	va = (vsid << 28) | (ea & 0x0fffffff);

	spin_lock(&beat_htab_lock);
	slot = beat_lpar_hpte_find(va, psize);
	BUG_ON(slot == -1);

	lpar_rc = beat_write_htab_entry(0, slot, 0, newpp, 0, 7,
		&dummy0, &dummy1);
	spin_unlock(&beat_htab_lock);

	BUG_ON(lpar_rc != 0);
}

static void beat_lpar_hpte_invalidate(unsigned long slot, unsigned long va,
					 int psize, int local)
{
	unsigned long want_v;
	unsigned long lpar_rc;
	unsigned long dummy1, dummy2;
	unsigned long flags;

	DBG_LOW("    inval : slot=%lx, va=%016lx, psize: %d, local: %d\n",
		slot, va, psize, local);
	want_v = hpte_encode_v(va, psize);

	spin_lock_irqsave(&beat_htab_lock, flags);
	dummy1 = beat_lpar_hpte_getword0(slot);

	if ((dummy1 & ~0x7FUL) != (want_v & ~0x7FUL)) {
		DBG_LOW("not found !\n");
		spin_unlock_irqrestore(&beat_htab_lock, flags);
		return;
	}

	lpar_rc = beat_write_htab_entry(0, slot, 0, 0, HPTE_V_VALID, 0,
		&dummy1, &dummy2);
	spin_unlock_irqrestore(&beat_htab_lock, flags);

	BUG_ON(lpar_rc != 0);
}

void __init hpte_init_beat(void)
{
	ppc_md.hpte_invalidate	= beat_lpar_hpte_invalidate;
	ppc_md.hpte_updatepp	= beat_lpar_hpte_updatepp;
	ppc_md.hpte_updateboltedpp = beat_lpar_hpte_updateboltedpp;
	ppc_md.hpte_insert	= beat_lpar_hpte_insert;
	ppc_md.hpte_remove	= beat_lpar_hpte_remove;
	ppc_md.hpte_clear_all	= beat_lpar_hptab_clear;
}