/* Copyright (c) 2010, 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.
 *
 * 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.
 */

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

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

DEFINE_SPINLOCK(msm_iommu_lock);

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

static void __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;

#ifndef CONFIG_IOMMU_PGTABLES_L2
	unsigned long *fl_table = priv->pgtable;
	int i;

	dmac_flush_range(fl_table, fl_table + SZ_16K);

	for (i = 0; i < NUM_FL_PTE; i++)
		if ((fl_table[i] & 0x03) == FL_TYPE_TABLE) {
			void *sl_table = __va(fl_table[i] & FL_BASE_MASK);
			dmac_flush_range(sl_table, sl_table + SZ_4K);
		}
#endif

	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);
		SET_CTX_TLBIALL(iommu_drvdata->base, ctx_drvdata->num, 0);
	}
}

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_CTX_TLBIALL(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);
	SET_CONTEXTIDR(base, ctx, 0);
}

static void __program_context(void __iomem *base, int ctx, phys_addr_t pgtable)
{
	__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 >> 14));

	/* Invalidate the TLB for this context */
	SET_CTX_TLBIALL(base, ctx, 0);

	/* Set interrupt number to "secure" interrupt */
	SET_IRPTNDX(base, ctx, 0);

	/* 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);

	/* Do not configure PRRR / NMRR on the IOMMU for now. We will assume
	 * TEX class 0 for everything until attributes are properly worked out
	 */
	SET_PRRR(base, ctx, 0);
	SET_NMRR(base, ctx, 0);

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

#ifdef CONFIG_IOMMU_PGTABLES_L2
	/* Configure page tables as inner-cacheable and shareable to reduce
	 * the TLB miss penalty.
	 */
	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 */
#endif

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

static int msm_iommu_domain_init(struct iommu_domain *domain)
{
	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;

	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;
	}

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

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

	list_add(&(ctx_drvdata->attached_elm), &priv->list_attached);
	__flush_iotlb(domain);

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;

	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;

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

fail:
	spin_unlock_irqrestore(&msm_iommu_lock, flags);
}

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;
	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;
	}

	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++)
			*(fl_pte+i) = (pa & 0xFF000000) | FL_SUPERSECTION |
				  FL_AP_READ | FL_AP_WRITE | FL_TYPE_SECT |
				  FL_SHARED;
	}

	if (len == SZ_1M)
		*fl_pte = (pa & 0xFFF00000) | FL_AP_READ | FL_AP_WRITE |
						FL_TYPE_SECT | FL_SHARED;

	/* Need a 2nd level table */
	if ((len == SZ_4K || len == SZ_64K) && (*fl_pte) == 0) {
		unsigned long *sl;
		sl = (unsigned long *) __get_free_pages(GFP_KERNEL,
							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);
	}

	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)
		*sl_pte = (pa & SL_BASE_MASK_SMALL) | SL_AP0 | SL_AP1 |
					  SL_SHARED | SL_TYPE_SMALL;

	if (len == SZ_64K) {
		int i;

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

	__flush_iotlb(domain);
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 (len == SZ_1M)
		*fl_pte = 0;

	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 (len == SZ_4K)
		*sl_pte = 0;

	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;
		}
	}

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

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;

	/* Invalidate context TLB */
	SET_CTX_TLBIALL(base, ctx, 0);
	SET_V2PPR_VA(base, ctx, va >> V2Pxx_VA_SHIFT);

	if (GET_FAULT(base, ctx))
		goto fail;

	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);

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 = 0;
	int ncb = 0, i = 0;

	spin_lock(&msm_iommu_lock);

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

	base = drvdata->base;

	pr_err("===== WOAH! =====\n");
	pr_err("Unexpected IOMMU page fault!\n");
	pr_err("base = %08x\n", (unsigned int) base);

	ncb = GET_NCB(base)+1;
	for (i = 0; i < 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);
		}
	}
fail:
	spin_unlock(&msm_iommu_lock);
	return 0;
}

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,
	.iova_to_phys = msm_iommu_iova_to_phys,
	.domain_has_cap = msm_iommu_domain_has_cap
};

static int msm_iommu_init(void)
{
	register_iommu(&msm_iommu_ops);
	return 0;
}

subsys_initcall(msm_iommu_init);

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