arch/arm/mach-msm/iommu.c

/* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * 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.
 */

#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/iommu.h>
#include <linux/clk.h>
#include <linux/scatterlist.h>

#include <asm/cacheflush.h>
#include <asm/sizes.h>

#include <mach/iommu_hw-8xxx.h>
#include <mach/iommu.h>

#define MRC(reg, processor, op1, crn, crm, op2)				\
__asm__ __volatile__ (							\
"   mrc   "   #processor "," #op1 ", %0,"  #crn "," #crm "," #op2 "\n"  \
: "=r" (reg))

#define RCP15_PRRR(reg)		MRC(reg, p15, 0, c10, c2, 0)
#define RCP15_NMRR(reg)		MRC(reg, p15, 0, c10, c2, 1)

/* Sharability attributes of MSM IOMMU mappings */
#define MSM_IOMMU_ATTR_NON_SH		0x0
#define MSM_IOMMU_ATTR_SH		0x4

/* Cacheability attributes of MSM IOMMU mappings */
#define MSM_IOMMU_ATTR_NONCACHED	0x0
#define MSM_IOMMU_ATTR_CACHED_WB_WA	0x1
#define MSM_IOMMU_ATTR_CACHED_WB_NWA	0x2
#define MSM_IOMMU_ATTR_CACHED_WT	0x3


static inline void clean_pte(unsigned long *start, unsigned long *end)
{
	dmac_flush_range(start, end);
}

static int msm_iommu_tex_class[4];

DEFINE_SPINLOCK(msm_iommu_lock);

struct msm_priv {
	unsigned long *pgtable;
	int redirect;
	struct list_head list_attached;
};

static int __enable_clocks(struct msm_iommu_drvdata *drvdata)
{
	int ret;

	ret = clk_enable(drvdata->pclk);
	if (ret)
		goto fail;

	if (drvdata->clk) {
		ret = clk_enable(drvdata->clk);
		if (ret)
			clk_disable(drvdata->pclk);
	}
fail:
	return ret;
}

static void __disable_clocks(struct msm_iommu_drvdata *drvdata)
{
	if (drvdata->clk)
		clk_disable(drvdata->clk);
	clk_disable(drvdata->pclk);
}

static int __flush_iotlb_va(struct iommu_domain *domain, unsigned int va)
{
	struct msm_priv *priv = domain->priv;
	struct msm_iommu_drvdata *iommu_drvdata;
	struct msm_iommu_ctx_drvdata *ctx_drvdata;
	int ret = 0;
	int asid;

	list_for_each_entry(ctx_drvdata, &priv->list_attached, attached_elm) {
		if (!ctx_drvdata->pdev || !ctx_drvdata->pdev->dev.parent)
			BUG();

		iommu_drvdata = dev_get_drvdata(ctx_drvdata->pdev->dev.parent);
		if (!iommu_drvdata)
			BUG();

		ret = __enable_clocks(iommu_drvdata);
		if (ret)
			goto fail;

		asid = GET_CONTEXTIDR_ASID(iommu_drvdata->base,
					   ctx_drvdata->num);

		SET_TLBIVA(iommu_drvdata->base, ctx_drvdata->num,
			   asid | (va & TLBIVA_VA));
		mb();
		__disable_clocks(iommu_drvdata);
	}
fail:
	return ret;
}

static int __flush_iotlb(struct iommu_domain *domain)
{
	struct msm_priv *priv = domain->priv;
	struct msm_iommu_drvdata *iommu_drvdata;
	struct msm_iommu_ctx_drvdata *ctx_drvdata;
	int ret = 0;
	int asid;

	list_for_each_entry(ctx_drvdata, &priv->list_attached, attached_elm) {
		if (!ctx_drvdata->pdev || !ctx_drvdata->pdev->dev.parent)
			BUG();

		iommu_drvdata = dev_get_drvdata(ctx_drvdata->pdev->dev.parent);
		if (!iommu_drvdata)
			BUG();

		ret = __enable_clocks(iommu_drvdata);
		if (ret)
			goto fail;

		asid = GET_CONTEXTIDR_ASID(iommu_drvdata->base,
					   ctx_drvdata->num);

		SET_TLBIASID(iommu_drvdata->base, ctx_drvdata->num, asid);
		mb();
		__disable_clocks(iommu_drvdata);
	}
fail:
	return ret;
}

static void __reset_context(void __iomem *base, int ctx)
{
	SET_BPRCOSH(base, ctx, 0);
	SET_BPRCISH(base, ctx, 0);
	SET_BPRCNSH(base, ctx, 0);
	SET_BPSHCFG(base, ctx, 0);
	SET_BPMTCFG(base, ctx, 0);
	SET_ACTLR(base, ctx, 0);
	SET_SCTLR(base, ctx, 0);
	SET_FSRRESTORE(base, ctx, 0);
	SET_TTBR0(base, ctx, 0);
	SET_TTBR1(base, ctx, 0);
	SET_TTBCR(base, ctx, 0);
	SET_BFBCR(base, ctx, 0);
	SET_PAR(base, ctx, 0);
	SET_FAR(base, ctx, 0);
	SET_TLBFLPTER(base, ctx, 0);
	SET_TLBSLPTER(base, ctx, 0);
	SET_TLBLKCR(base, ctx, 0);
	SET_PRRR(base, ctx, 0);
	SET_NMRR(base, ctx, 0);
	mb();
}

static void __program_context(void __iomem *base, int ctx, int ncb,
			      phys_addr_t pgtable, int redirect)
{
	unsigned int prrr, nmrr;
	int i, j, found;
	__reset_context(base, ctx);

	/* Set up HTW mode */
	/* TLB miss configuration: perform HTW on miss */
	SET_TLBMCFG(base, ctx, 0x3);

	/* V2P configuration: HTW for access */
	SET_V2PCFG(base, ctx, 0x3);

	SET_TTBCR(base, ctx, 0);
	SET_TTBR0_PA(base, ctx, (pgtable >> TTBR0_PA_SHIFT));

	/* Enable context fault interrupt */
	SET_CFEIE(base, ctx, 1);

	/* Stall access on a context fault and let the handler deal with it */
	SET_CFCFG(base, ctx, 1);

	/* Redirect all cacheable requests to L2 slave port. */
	SET_RCISH(base, ctx, 1);
	SET_RCOSH(base, ctx, 1);
	SET_RCNSH(base, ctx, 1);

	/* Turn on TEX Remap */
	SET_TRE(base, ctx, 1);

	/* Set TEX remap attributes */
	RCP15_PRRR(prrr);
	RCP15_NMRR(nmrr);
	SET_PRRR(base, ctx, prrr);
	SET_NMRR(base, ctx, nmrr);

	/* Turn on BFB prefetch */
	SET_BFBDFE(base, ctx, 1);

	/* Configure page tables as inner-cacheable and shareable to reduce
	 * the TLB miss penalty.
	 */
	if (redirect) {
		SET_TTBR0_SH(base, ctx, 1);
		SET_TTBR1_SH(base, ctx, 1);

		SET_TTBR0_NOS(base, ctx, 1);
		SET_TTBR1_NOS(base, ctx, 1);

		SET_TTBR0_IRGNH(base, ctx, 0); /* WB, WA */
		SET_TTBR0_IRGNL(base, ctx, 1);

		SET_TTBR1_IRGNH(base, ctx, 0); /* WB, WA */
		SET_TTBR1_IRGNL(base, ctx, 1);

		SET_TTBR0_ORGN(base, ctx, 1); /* WB, WA */
		SET_TTBR1_ORGN(base, ctx, 1); /* WB, WA */
	}

	/* Find if this page table is used elsewhere, and re-use ASID */
	found = 0;
	for (i = 0; i < ncb; i++)
		if (GET_TTBR0_PA(base, i) == (pgtable >> TTBR0_PA_SHIFT) &&
		    i != ctx) {
			SET_CONTEXTIDR_ASID(base, ctx, \
					    GET_CONTEXTIDR_ASID(base, i));
			found = 1;
			break;
		}

	/* If page table is new, find an unused ASID */
	if (!found) {
		for (i = 0; i < ncb; i++) {
			found = 0;
			for (j = 0; j < ncb; j++) {
				if (GET_CONTEXTIDR_ASID(base, j) == i &&
				    j != ctx)
					found = 1;
			}

			if (!found) {
				SET_CONTEXTIDR_ASID(base, ctx, i);
				break;
			}
		}
		BUG_ON(found);
	}

	/* Enable the MMU */
	SET_M(base, ctx, 1);
	mb();
}

static int msm_iommu_domain_init(struct iommu_domain *domain, int flags)
{
	struct msm_priv *priv = kzalloc(sizeof(*priv), GFP_KERNEL);

	if (!priv)
		goto fail_nomem;

	INIT_LIST_HEAD(&priv->list_attached);
	priv->pgtable = (unsigned long *)__get_free_pages(GFP_KERNEL,
							  get_order(SZ_16K));

	if (!priv->pgtable)
		goto fail_nomem;

#ifdef CONFIG_IOMMU_PGTABLES_L2
	priv->redirect = flags & MSM_IOMMU_DOMAIN_PT_CACHEABLE;
#endif

	memset(priv->pgtable, 0, SZ_16K);
	domain->priv = priv;
	return 0;

fail_nomem:
	kfree(priv);
	return -ENOMEM;
}

static void msm_iommu_domain_destroy(struct iommu_domain *domain)
{
	struct msm_priv *priv;
	unsigned long flags;
	unsigned long *fl_table;
	int i;

	spin_lock_irqsave(&msm_iommu_lock, flags);
	priv = domain->priv;
	domain->priv = NULL;

	if (priv) {
		fl_table = priv->pgtable;

		for (i = 0; i < NUM_FL_PTE; i++)
			if ((fl_table[i] & 0x03) == FL_TYPE_TABLE)
				free_page((unsigned long) __va(((fl_table[i]) &
								FL_BASE_MASK)));

		free_pages((unsigned long)priv->pgtable, get_order(SZ_16K));
		priv->pgtable = NULL;
	}

	kfree(priv);
	spin_unlock_irqrestore(&msm_iommu_lock, flags);
}

static int msm_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
{
	struct msm_priv *priv;
	struct msm_iommu_ctx_dev *ctx_dev;
	struct msm_iommu_drvdata *iommu_drvdata;
	struct msm_iommu_ctx_drvdata *ctx_drvdata;
	struct msm_iommu_ctx_drvdata *tmp_drvdata;
	int ret = 0;
	unsigned long flags;

	spin_lock_irqsave(&msm_iommu_lock, flags);

	priv = domain->priv;

	if (!priv || !dev) {
		ret = -EINVAL;
		goto fail;
	}

	iommu_drvdata = dev_get_drvdata(dev->parent);
	ctx_drvdata = dev_get_drvdata(dev);
	ctx_dev = dev->platform_data;

	if (!iommu_drvdata || !ctx_drvdata || !ctx_dev) {
		ret = -EINVAL;
		goto fail;
	}

	if (!list_empty(&ctx_drvdata->attached_elm)) {
		ret = -EBUSY;
		goto fail;
	}

	list_for_each_entry(tmp_drvdata, &priv->list_attached, attached_elm)
		if (tmp_drvdata == ctx_drvdata) {
			ret = -EBUSY;
			goto fail;
		}

	ret = __enable_clocks(iommu_drvdata);
	if (ret)
		goto fail;

	__program_context(iommu_drvdata->base, ctx_dev->num, iommu_drvdata->ncb,
			  __pa(priv->pgtable), priv->redirect);

	__disable_clocks(iommu_drvdata);
	list_add(&(ctx_drvdata->attached_elm), &priv->list_attached);

fail:
	spin_unlock_irqrestore(&msm_iommu_lock, flags);
	return ret;
}

static void msm_iommu_detach_dev(struct iommu_domain *domain,
				 struct device *dev)
{
	struct msm_priv *priv;
	struct msm_iommu_ctx_dev *ctx_dev;
	struct msm_iommu_drvdata *iommu_drvdata;
	struct msm_iommu_ctx_drvdata *ctx_drvdata;
	unsigned long flags;
	int ret;

	spin_lock_irqsave(&msm_iommu_lock, flags);
	priv = domain->priv;

	if (!priv || !dev)
		goto fail;

	iommu_drvdata = dev_get_drvdata(dev->parent);
	ctx_drvdata = dev_get_drvdata(dev);
	ctx_dev = dev->platform_data;

	if (!iommu_drvdata || !ctx_drvdata || !ctx_dev)
		goto fail;

	ret = __enable_clocks(iommu_drvdata);
	if (ret)
		goto fail;

	SET_TLBIASID(iommu_drvdata->base, ctx_dev->num,
		     GET_CONTEXTIDR_ASID(iommu_drvdata->base, ctx_dev->num));

	__reset_context(iommu_drvdata->base, ctx_dev->num);
	__disable_clocks(iommu_drvdata);
	list_del_init(&ctx_drvdata->attached_elm);

fail:
	spin_unlock_irqrestore(&msm_iommu_lock, flags);
}

static int __get_pgprot(int prot, int len)
{
	unsigned int pgprot;
	int tex;

	if (prot & IOMMU_CACHE)
		tex = (pgprot_kernel >> 2) & 0x07;
	else
		tex = msm_iommu_tex_class[MSM_IOMMU_ATTR_NONCACHED];

	if (tex < 0 || tex > NUM_TEX_CLASS - 1)
		return 0;

	if (len == SZ_16M || len == SZ_1M) {
		pgprot = FL_SHARED;
		pgprot |= tex & 0x01 ? FL_BUFFERABLE : 0;
		pgprot |= tex & 0x02 ? FL_CACHEABLE : 0;
		pgprot |= tex & 0x04 ? FL_TEX0 : 0;
	} else	{
		pgprot = SL_SHARED;
		pgprot |= tex & 0x01 ? SL_BUFFERABLE : 0;
		pgprot |= tex & 0x02 ? SL_CACHEABLE : 0;
		pgprot |= tex & 0x04 ? SL_TEX0 : 0;
	}

	return pgprot;
}

static int msm_iommu_map(struct iommu_domain *domain, unsigned long va,
			 phys_addr_t pa, int order, int prot)
{
	struct msm_priv *priv;
	unsigned long flags;
	unsigned long *fl_table;
	unsigned long *fl_pte;
	unsigned long fl_offset;
	unsigned long *sl_table;
	unsigned long *sl_pte;
	unsigned long sl_offset;
	unsigned int pgprot;
	size_t len = 0x1000UL << order;
	int ret = 0;

	spin_lock_irqsave(&msm_iommu_lock, flags);

	priv = domain->priv;
	if (!priv) {
		ret = -EINVAL;
		goto fail;
	}

	fl_table = priv->pgtable;

	if (len != SZ_16M && len != SZ_1M &&
	    len != SZ_64K && len != SZ_4K) {
		pr_debug("Bad size: %d\n", len);
		ret = -EINVAL;
		goto fail;
	}

	if (!fl_table) {
		pr_debug("Null page table\n");
		ret = -EINVAL;
		goto fail;
	}

	pgprot = __get_pgprot(prot, len);

	if (!pgprot) {
		ret = -EINVAL;
		goto fail;
	}

	fl_offset = FL_OFFSET(va);	/* Upper 12 bits */
	fl_pte = fl_table + fl_offset;	/* int pointers, 4 bytes */

	if (len == SZ_16M) {
		int i = 0;

		for (i = 0; i < 16; i++)
			if (*(fl_pte+i)) {
				ret = -EBUSY;
				goto fail;
			}

		for (i = 0; i < 16; i++)
			*(fl_pte+i) = (pa & 0xFF000000) | FL_SUPERSECTION |
				  FL_AP_READ | FL_AP_WRITE | FL_TYPE_SECT |
				  FL_SHARED | FL_NG | pgprot;
		if (!priv->redirect)
			clean_pte(fl_pte, fl_pte + 16);
	}

	if (len == SZ_1M) {
		if (*fl_pte) {
			ret = -EBUSY;
			goto fail;
		}

		*fl_pte = (pa & 0xFFF00000) | FL_AP_READ | FL_AP_WRITE | FL_NG |
					    FL_TYPE_SECT | FL_SHARED | pgprot;
		if (!priv->redirect)
			clean_pte(fl_pte, fl_pte + 1);
	}

	/* Need a 2nd level table */
	if (len == SZ_4K || len == SZ_64K) {

		if (*fl_pte == 0) {
			unsigned long *sl;
			sl = (unsigned long *) __get_free_pages(GFP_ATOMIC,
							get_order(SZ_4K));

			if (!sl) {
				pr_debug("Could not allocate second level table\n");
				ret = -ENOMEM;
				goto fail;
			}
			memset(sl, 0, SZ_4K);

			*fl_pte = ((((int)__pa(sl)) & FL_BASE_MASK) | \
						      FL_TYPE_TABLE);

			if (!priv->redirect)
				clean_pte(fl_pte, fl_pte + 1);
		}

		if (!(*fl_pte & FL_TYPE_TABLE)) {
			ret = -EBUSY;
			goto fail;
		}
	}

	sl_table = (unsigned long *) __va(((*fl_pte) & FL_BASE_MASK));
	sl_offset = SL_OFFSET(va);
	sl_pte = sl_table + sl_offset;

	if (len == SZ_4K) {
		if (*sl_pte) {
			ret = -EBUSY;
			goto fail;
		}

		*sl_pte = (pa & SL_BASE_MASK_SMALL) | SL_AP0 | SL_AP1 | SL_NG |
					  SL_SHARED | SL_TYPE_SMALL | pgprot;
		if (!priv->redirect)
			clean_pte(sl_pte, sl_pte + 1);
	}

	if (len == SZ_64K) {
		int i;

		for (i = 0; i < 16; i++)
			if (*(sl_pte+i)) {
				ret = -EBUSY;
				goto fail;
			}

		for (i = 0; i < 16; i++)
			*(sl_pte+i) = (pa & SL_BASE_MASK_LARGE) | SL_AP0 |
			    SL_NG | SL_AP1 | SL_SHARED | SL_TYPE_LARGE | pgprot;

		if (!priv->redirect)
			clean_pte(sl_pte, sl_pte + 16);
	}

	ret = __flush_iotlb_va(domain, va);
fail:
	spin_unlock_irqrestore(&msm_iommu_lock, flags);
	return ret;
}

static int msm_iommu_unmap(struct iommu_domain *domain, unsigned long va,
			    int order)
{
	struct msm_priv *priv;
	unsigned long flags;
	unsigned long *fl_table;
	unsigned long *fl_pte;
	unsigned long fl_offset;
	unsigned long *sl_table;
	unsigned long *sl_pte;
	unsigned long sl_offset;
	size_t len = 0x1000UL << order;
	int i, ret = 0;

	spin_lock_irqsave(&msm_iommu_lock, flags);

	priv = domain->priv;

	if (!priv) {
		ret = -ENODEV;
		goto fail;
	}

	fl_table = priv->pgtable;

	if (len != SZ_16M && len != SZ_1M &&
	    len != SZ_64K && len != SZ_4K) {
		pr_debug("Bad length: %d\n", len);
		ret = -EINVAL;
		goto fail;
	}

	if (!fl_table) {
		pr_debug("Null page table\n");
		ret = -EINVAL;
		goto fail;
	}

	fl_offset = FL_OFFSET(va);	/* Upper 12 bits */
	fl_pte = fl_table + fl_offset;	/* int pointers, 4 bytes */

	if (*fl_pte == 0) {
		pr_debug("First level PTE is 0\n");
		ret = -ENODEV;
		goto fail;
	}

	/* Unmap supersection */
	if (len == SZ_16M) {
		for (i = 0; i < 16; i++)
			*(fl_pte+i) = 0;

		if (!priv->redirect)
			clean_pte(fl_pte, fl_pte + 16);
	}

	if (len == SZ_1M) {
		*fl_pte = 0;

		if (!priv->redirect)
			clean_pte(fl_pte, fl_pte + 1);
	}

	sl_table = (unsigned long *) __va(((*fl_pte) & FL_BASE_MASK));
	sl_offset = SL_OFFSET(va);
	sl_pte = sl_table + sl_offset;

	if (len == SZ_64K) {
		for (i = 0; i < 16; i++)
			*(sl_pte+i) = 0;

		if (!priv->redirect)
			clean_pte(sl_pte, sl_pte + 16);
	}

	if (len == SZ_4K) {
		*sl_pte = 0;

		if (!priv->redirect)
			clean_pte(sl_pte, sl_pte + 1);
	}

	if (len == SZ_4K || len == SZ_64K) {
		int used = 0;

		for (i = 0; i < NUM_SL_PTE; i++)
			if (sl_table[i])
				used = 1;
		if (!used) {
			free_page((unsigned long)sl_table);
			*fl_pte = 0;

			if (!priv->redirect)
				clean_pte(fl_pte, fl_pte + 1);
		}
	}

	ret = __flush_iotlb_va(domain, va);
fail:
	spin_unlock_irqrestore(&msm_iommu_lock, flags);
	return ret;
}

static int msm_iommu_map_range(struct iommu_domain *domain, unsigned int va,
			       struct scatterlist *sg, unsigned int len,
			       int prot)
{
	unsigned int pa;
	unsigned int offset = 0;
	unsigned int pgprot;
	unsigned long *fl_table;
	unsigned long *fl_pte;
	unsigned long fl_offset;
	unsigned long *sl_table;
	unsigned long sl_offset, sl_start;
	unsigned long flags;
	unsigned int chunk_offset = 0;
	unsigned int chunk_pa;
	int ret = 0;
	struct msm_priv *priv;

	spin_lock_irqsave(&msm_iommu_lock, flags);

	BUG_ON(len & (SZ_4K - 1));

	priv = domain->priv;
	fl_table = priv->pgtable;

	pgprot = __get_pgprot(prot, SZ_4K);

	if (!pgprot) {
		ret = -EINVAL;
		goto fail;
	}

	fl_offset = FL_OFFSET(va);	/* Upper 12 bits */
	fl_pte = fl_table + fl_offset;	/* int pointers, 4 bytes */

	sl_table = (unsigned long *) __va(((*fl_pte) & FL_BASE_MASK));
	sl_offset = SL_OFFSET(va);

	chunk_pa = sg_phys(sg);

	while (offset < len) {
		/* Set up a 2nd level page table if one doesn't exist */
		if (*fl_pte == 0) {
			sl_table = (unsigned long *)
				 __get_free_pages(GFP_ATOMIC, get_order(SZ_4K));

			if (!sl_table) {
				pr_debug("Could not allocate second level table\n");
				ret = -ENOMEM;
				goto fail;
			}

			memset(sl_table, 0, SZ_4K);
			*fl_pte = ((((int)__pa(sl_table)) & FL_BASE_MASK) |
							    FL_TYPE_TABLE);
			if (!priv->redirect)
				clean_pte(fl_pte, fl_pte + 1);
		} else
			sl_table = (unsigned long *)
					       __va(((*fl_pte) & FL_BASE_MASK));

		/* Keep track of initial position so we
		 * don't clean more than we have to
		 */
		sl_start = sl_offset;

		/* Build the 2nd level page table */
		while (offset < len && sl_offset < NUM_SL_PTE) {
			pa = chunk_pa + chunk_offset;
			sl_table[sl_offset] = (pa & SL_BASE_MASK_SMALL) |
					      pgprot | SL_AP0 | SL_AP1 | SL_NG |
					      SL_SHARED | SL_TYPE_SMALL;
			sl_offset++;
			offset += SZ_4K;

			chunk_offset += SZ_4K;

			if (chunk_offset >= sg->length && offset < len) {
				chunk_offset = 0;
				sg = sg_next(sg);
				chunk_pa = sg_phys(sg);
			}
		}

		if (!priv->redirect)
			clean_pte(sl_table + sl_start, sl_table + sl_offset);

		fl_pte++;
		sl_offset = 0;
	}
	__flush_iotlb(domain);
fail:
	spin_unlock_irqrestore(&msm_iommu_lock, flags);
	return ret;
}


static int msm_iommu_unmap_range(struct iommu_domain *domain, unsigned int va,
				 unsigned int len)
{
	unsigned int offset = 0;
	unsigned long *fl_table;
	unsigned long *fl_pte;
	unsigned long fl_offset;
	unsigned long *sl_table;
	unsigned long sl_start, sl_end;
	unsigned long flags;
	int used, i;
	struct msm_priv *priv;

	spin_lock_irqsave(&msm_iommu_lock, flags);

	BUG_ON(len & (SZ_4K - 1));

	priv = domain->priv;
	fl_table = priv->pgtable;

	fl_offset = FL_OFFSET(va);	/* Upper 12 bits */
	fl_pte = fl_table + fl_offset;	/* int pointers, 4 bytes */

	sl_start = SL_OFFSET(va);

	while (offset < len) {
		sl_table = (unsigned long *) __va(((*fl_pte) & FL_BASE_MASK));
		sl_end = ((len - offset) / SZ_4K) + sl_start;

		if (sl_end > NUM_SL_PTE)
			sl_end = NUM_SL_PTE;

		memset(sl_table + sl_start, 0, (sl_end - sl_start) * 4);
		if (!priv->redirect)
			clean_pte(sl_table + sl_start, sl_table + sl_end);

		offset += (sl_end - sl_start) * SZ_4K;

		/* Unmap and free the 2nd level table if all mappings in it
		 * were removed. This saves memory, but the table will need
		 * to be re-allocated the next time someone tries to map these
		 * VAs.
		 */
		used = 0;

		/* If we just unmapped the whole table, don't bother
		 * seeing if there are still used entries left.
		 */
		if (sl_end - sl_start != NUM_SL_PTE)
			for (i = 0; i < NUM_SL_PTE; i++)
				if (sl_table[i]) {
					used = 1;
					break;
				}
		if (!used) {
			free_page((unsigned long)sl_table);
			*fl_pte = 0;

			if (!priv->redirect)
				clean_pte(fl_pte, fl_pte + 1);
		}

		sl_start = 0;
		fl_pte++;
	}

	__flush_iotlb(domain);
	spin_unlock_irqrestore(&msm_iommu_lock, flags);
	return 0;
}

static phys_addr_t msm_iommu_iova_to_phys(struct iommu_domain *domain,
					  unsigned long va)
{
	struct msm_priv *priv;
	struct msm_iommu_drvdata *iommu_drvdata;
	struct msm_iommu_ctx_drvdata *ctx_drvdata;
	unsigned int par;
	unsigned long flags;
	void __iomem *base;
	phys_addr_t ret = 0;
	int ctx;

	spin_lock_irqsave(&msm_iommu_lock, flags);

	priv = domain->priv;
	if (list_empty(&priv->list_attached))
		goto fail;

	ctx_drvdata = list_entry(priv->list_attached.next,
				 struct msm_iommu_ctx_drvdata, attached_elm);
	iommu_drvdata = dev_get_drvdata(ctx_drvdata->pdev->dev.parent);

	base = iommu_drvdata->base;
	ctx = ctx_drvdata->num;

	ret = __enable_clocks(iommu_drvdata);
	if (ret)
		goto fail;

	SET_V2PPR(base, ctx, va & V2Pxx_VA);

	mb();
	par = GET_PAR(base, ctx);

	/* We are dealing with a supersection */
	if (GET_NOFAULT_SS(base, ctx))
		ret = (par & 0xFF000000) | (va & 0x00FFFFFF);
	else	/* Upper 20 bits from PAR, lower 12 from VA */
		ret = (par & 0xFFFFF000) | (va & 0x00000FFF);

	if (GET_FAULT(base, ctx))
		ret = 0;

	__disable_clocks(iommu_drvdata);
fail:
	spin_unlock_irqrestore(&msm_iommu_lock, flags);
	return ret;
}

static int msm_iommu_domain_has_cap(struct iommu_domain *domain,
				    unsigned long cap)
{
	return 0;
}

static void print_ctx_regs(void __iomem *base, int ctx)
{
	unsigned int fsr = GET_FSR(base, ctx);
	pr_err("FAR    = %08x    PAR    = %08x\n",
	       GET_FAR(base, ctx), GET_PAR(base, ctx));
	pr_err("FSR    = %08x [%s%s%s%s%s%s%s%s%s%s]\n", fsr,
			(fsr & 0x02) ? "TF " : "",
			(fsr & 0x04) ? "AFF " : "",
			(fsr & 0x08) ? "APF " : "",
			(fsr & 0x10) ? "TLBMF " : "",
			(fsr & 0x20) ? "HTWDEEF " : "",
			(fsr & 0x40) ? "HTWSEEF " : "",
			(fsr & 0x80) ? "MHF " : "",
			(fsr & 0x10000) ? "SL " : "",
			(fsr & 0x40000000) ? "SS " : "",
			(fsr & 0x80000000) ? "MULTI " : "");

	pr_err("FSYNR0 = %08x    FSYNR1 = %08x\n",
	       GET_FSYNR0(base, ctx), GET_FSYNR1(base, ctx));
	pr_err("TTBR0  = %08x    TTBR1  = %08x\n",
	       GET_TTBR0(base, ctx), GET_TTBR1(base, ctx));
	pr_err("SCTLR  = %08x    ACTLR  = %08x\n",
	       GET_SCTLR(base, ctx), GET_ACTLR(base, ctx));
	pr_err("PRRR   = %08x    NMRR   = %08x\n",
	       GET_PRRR(base, ctx), GET_NMRR(base, ctx));
}

irqreturn_t msm_iommu_fault_handler(int irq, void *dev_id)
{
	struct msm_iommu_drvdata *drvdata = dev_id;
	void __iomem *base;
	unsigned int fsr;
	int i, ret;

	spin_lock(&msm_iommu_lock);

	if (!drvdata) {
		pr_err("Invalid device ID in context interrupt handler\n");
		goto fail;
	}

	base = drvdata->base;

	pr_err("Unexpected IOMMU page fault!\n");
	pr_err("base = %08x\n", (unsigned int) base);
	pr_err("name = %s\n", drvdata->name);

	ret = __enable_clocks(drvdata);
	if (ret)
		goto fail;

	for (i = 0; i < drvdata->ncb; i++) {
		fsr = GET_FSR(base, i);
		if (fsr) {
			pr_err("Fault occurred in context %d.\n", i);
			pr_err("Interesting registers:\n");
			print_ctx_regs(base, i);
			SET_FSR(base, i, 0x4000000F);
		}
	}
	__disable_clocks(drvdata);
fail:
	spin_unlock(&msm_iommu_lock);
	return 0;
}

static phys_addr_t msm_iommu_get_pt_base_addr(struct iommu_domain *domain)
{
	struct msm_priv *priv = domain->priv;
	return __pa(priv->pgtable);
}

static struct iommu_ops msm_iommu_ops = {
	.domain_init = msm_iommu_domain_init,
	.domain_destroy = msm_iommu_domain_destroy,
	.attach_dev = msm_iommu_attach_dev,
	.detach_dev = msm_iommu_detach_dev,
	.map = msm_iommu_map,
	.unmap = msm_iommu_unmap,
	.map_range = msm_iommu_map_range,
	.unmap_range = msm_iommu_unmap_range,
	.iova_to_phys = msm_iommu_iova_to_phys,
	.domain_has_cap = msm_iommu_domain_has_cap,
	.get_pt_base_addr = msm_iommu_get_pt_base_addr
};

static int __init get_tex_class(int icp, int ocp, int mt, int nos)
{
	int i = 0;
	unsigned int prrr = 0;
	unsigned int nmrr = 0;
	int c_icp, c_ocp, c_mt, c_nos;

	RCP15_PRRR(prrr);
	RCP15_NMRR(nmrr);

	for (i = 0; i < NUM_TEX_CLASS; i++) {
		c_nos = PRRR_NOS(prrr, i);
		c_mt = PRRR_MT(prrr, i);
		c_icp = NMRR_ICP(nmrr, i);
		c_ocp = NMRR_OCP(nmrr, i);

		if (icp == c_icp && ocp == c_ocp && c_mt == mt && c_nos == nos)
			return i;
	}

	return -ENODEV;
}

static void __init setup_iommu_tex_classes(void)
{
	msm_iommu_tex_class[MSM_IOMMU_ATTR_NONCACHED] =
			get_tex_class(CP_NONCACHED, CP_NONCACHED, MT_NORMAL, 1);

	msm_iommu_tex_class[MSM_IOMMU_ATTR_CACHED_WB_WA] =
			get_tex_class(CP_WB_WA, CP_WB_WA, MT_NORMAL, 1);

	msm_iommu_tex_class[MSM_IOMMU_ATTR_CACHED_WB_NWA] =
			get_tex_class(CP_WB_NWA, CP_WB_NWA, MT_NORMAL, 1);

	msm_iommu_tex_class[MSM_IOMMU_ATTR_CACHED_WT] =
			get_tex_class(CP_WT, CP_WT, MT_NORMAL, 1);
}

static int __init msm_iommu_init(void)
{
	if (!msm_soc_version_supports_iommu())
		return -ENODEV;

	setup_iommu_tex_classes();
	register_iommu(&msm_iommu_ops);
	return 0;
}

subsys_initcall(msm_iommu_init);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Stepan Moskovchenko <stepanm@codeaurora.org>");