omap: iommu/iovmm: move to dedicated iommu folder

Move OMAP's iommu drivers to the dedicated iommu drivers folder.

While OMAP's iovmm (virtual memory manager) driver does not strictly
belong to the iommu drivers folder, move it there as well, because
it's by no means OMAP-specific (in concept. technically it is still
coupled with OMAP's iommu).

Eventually, iovmm will be completely replaced with the generic,
iommu-based, dma-mapping API.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 923 insertions, 0 deletions

diff --git a/drivers/iommu/omap-iovmm.c b/drivers/iommu/omap-iovmm.c
new file mode 100644
index 000000000000..809ca124196e
--- /dev/null
+++ b/drivers/iommu/omap-iovmm.c
@@ -0,0 +1,923 @@
+/*
+ * omap iommu: simple virtual address space management
+ *
+ * Copyright (C) 2008-2009 Nokia Corporation
+ *
+ * Written by Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/device.h>
+#include <linux/scatterlist.h>
+#include <linux/iommu.h>
+
+#include <asm/cacheflush.h>
+#include <asm/mach/map.h>
+
+#include <plat/iommu.h>
+#include <plat/iovmm.h>
+
+#include <plat/iopgtable.h>
+
+/*
+ * A device driver needs to create address mappings between:
+ *
+ * - iommu/device address
+ * - physical address
+ * - mpu virtual address
+ *
+ * There are 4 possible patterns for them:
+ *
+ *    |iova/                      mapping               iommu_          page
+ *    | da      pa      va      (d)-(p)-(v)             function        type
+ *  ---------------------------------------------------------------------------
+ *  1 | c       c       c        1 - 1 - 1        _kmap() / _kunmap()   s
+ *  2 | c       c,a     c        1 - 1 - 1      _kmalloc()/ _kfree()    s
+ *  3 | c       d       c        1 - n - 1        _vmap() / _vunmap()   s
+ *  4 | c       d,a     c        1 - n - 1      _vmalloc()/ _vfree()    n*
+ *
+ *
+ *      'iova': device iommu virtual address
+ *      'da':   alias of 'iova'
+ *      'pa':   physical address
+ *      'va':   mpu virtual address
+ *
+ *      'c':    contiguous memory area
+ *      'd':    discontiguous memory area
+ *      'a':    anonymous memory allocation
+ *      '()':   optional feature
+ *
+ *      'n':    a normal page(4KB) size is used.
+ *      's':    multiple iommu superpage(16MB, 1MB, 64KB, 4KB) size is used.
+ *
+ *      '*':    not yet, but feasible.
+ */
+
+static struct kmem_cache *iovm_area_cachep;
+
+/* return total bytes of sg buffers */
+static size_t sgtable_len(const struct sg_table *sgt)
+{
+        unsigned int i, total = 0;
+        struct scatterlist *sg;
+
+        if (!sgt)
+                return 0;
+
+        for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+                size_t bytes;
+
+                bytes = sg->length;
+
+                if (!iopgsz_ok(bytes)) {
+                        pr_err("%s: sg[%d] not iommu pagesize(%x)\n",
+                               __func__, i, bytes);
+                        return 0;
+                }
+
+                total += bytes;
+        }
+
+        return total;
+}
+#define sgtable_ok(x)   (!!sgtable_len(x))
+
+static unsigned max_alignment(u32 addr)
+{
+        int i;
+        unsigned pagesize[] = { SZ_16M, SZ_1M, SZ_64K, SZ_4K, };
+        for (i = 0; i < ARRAY_SIZE(pagesize) && addr & (pagesize[i] - 1); i++)
+                ;
+        return (i < ARRAY_SIZE(pagesize)) ? pagesize[i] : 0;
+}
+
+/*
+ * calculate the optimal number sg elements from total bytes based on
+ * iommu superpages
+ */
+static unsigned sgtable_nents(size_t bytes, u32 da, u32 pa)
+{
+        unsigned nr_entries = 0, ent_sz;
+
+        if (!IS_ALIGNED(bytes, PAGE_SIZE)) {
+                pr_err("%s: wrong size %08x\n", __func__, bytes);
+                return 0;
+        }
+
+        while (bytes) {
+                ent_sz = max_alignment(da | pa);
+                ent_sz = min_t(unsigned, ent_sz, iopgsz_max(bytes));
+                nr_entries++;
+                da += ent_sz;
+                pa += ent_sz;
+                bytes -= ent_sz;
+        }
+
+        return nr_entries;
+}
+
+/* allocate and initialize sg_table header(a kind of 'superblock') */
+static struct sg_table *sgtable_alloc(const size_t bytes, u32 flags,
+                                                        u32 da, u32 pa)
+{
+        unsigned int nr_entries;
+        int err;
+        struct sg_table *sgt;
+
+        if (!bytes)
+                return ERR_PTR(-EINVAL);
+
+        if (!IS_ALIGNED(bytes, PAGE_SIZE))
+                return ERR_PTR(-EINVAL);
+
+        if (flags & IOVMF_LINEAR) {
+                nr_entries = sgtable_nents(bytes, da, pa);
+                if (!nr_entries)
+                        return ERR_PTR(-EINVAL);
+        } else
+                nr_entries =  bytes / PAGE_SIZE;
+
+        sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
+        if (!sgt)
+                return ERR_PTR(-ENOMEM);
+
+        err = sg_alloc_table(sgt, nr_entries, GFP_KERNEL);
+        if (err) {
+                kfree(sgt);
+                return ERR_PTR(err);
+        }
+
+        pr_debug("%s: sgt:%p(%d entries)\n", __func__, sgt, nr_entries);
+
+        return sgt;
+}
+
+/* free sg_table header(a kind of superblock) */
+static void sgtable_free(struct sg_table *sgt)
+{
+        if (!sgt)
+                return;
+
+        sg_free_table(sgt);
+        kfree(sgt);
+
+        pr_debug("%s: sgt:%p\n", __func__, sgt);
+}
+
+/* map 'sglist' to a contiguous mpu virtual area and return 'va' */
+static void *vmap_sg(const struct sg_table *sgt)
+{
+        u32 va;
+        size_t total;
+        unsigned int i;
+        struct scatterlist *sg;
+        struct vm_struct *new;
+        const struct mem_type *mtype;
+
+        mtype = get_mem_type(MT_DEVICE);
+        if (!mtype)
+                return ERR_PTR(-EINVAL);
+
+        total = sgtable_len(sgt);
+        if (!total)
+                return ERR_PTR(-EINVAL);
+
+        new = __get_vm_area(total, VM_IOREMAP, VMALLOC_START, VMALLOC_END);
+        if (!new)
+                return ERR_PTR(-ENOMEM);
+        va = (u32)new->addr;
+
+        for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+                size_t bytes;
+                u32 pa;
+                int err;
+
+                pa = sg_phys(sg);
+                bytes = sg->length;
+
+                BUG_ON(bytes != PAGE_SIZE);
+
+                err = ioremap_page(va,  pa, mtype);
+                if (err)
+                        goto err_out;
+
+                va += bytes;
+        }
+
+        flush_cache_vmap((unsigned long)new->addr,
+                                (unsigned long)(new->addr + total));
+        return new->addr;
+
+err_out:
+        WARN_ON(1); /* FIXME: cleanup some mpu mappings */
+        vunmap(new->addr);
+        return ERR_PTR(-EAGAIN);
+}
+
+static inline void vunmap_sg(const void *va)
+{
+        vunmap(va);
+}
+
+static struct iovm_struct *__find_iovm_area(struct iommu *obj, const u32 da)
+{
+        struct iovm_struct *tmp;
+
+        list_for_each_entry(tmp, &obj->mmap, list) {
+                if ((da >= tmp->da_start) && (da < tmp->da_end)) {
+                        size_t len;
+
+                        len = tmp->da_end - tmp->da_start;
+
+                        dev_dbg(obj->dev, "%s: %08x-%08x-%08x(%x) %08x\n",
+                                __func__, tmp->da_start, da, tmp->da_end, len,
+                                tmp->flags);
+
+                        return tmp;
+                }
+        }
+
+        return NULL;
+}
+
+/**
+ * find_iovm_area  -  find iovma which includes @da
+ * @da:         iommu device virtual address
+ *
+ * Find the existing iovma starting at @da
+ */
+struct iovm_struct *find_iovm_area(struct iommu *obj, u32 da)
+{
+        struct iovm_struct *area;
+
+        mutex_lock(&obj->mmap_lock);
+        area = __find_iovm_area(obj, da);
+        mutex_unlock(&obj->mmap_lock);
+
+        return area;
+}
+EXPORT_SYMBOL_GPL(find_iovm_area);
+
+/*
+ * This finds the hole(area) which fits the requested address and len
+ * in iovmas mmap, and returns the new allocated iovma.
+ */
+static struct iovm_struct *alloc_iovm_area(struct iommu *obj, u32 da,
+                                           size_t bytes, u32 flags)
+{
+        struct iovm_struct *new, *tmp;
+        u32 start, prev_end, alignment;
+
+        if (!obj || !bytes)
+                return ERR_PTR(-EINVAL);
+
+        start = da;
+        alignment = PAGE_SIZE;
+
+        if (~flags & IOVMF_DA_FIXED) {
+                /* Don't map address 0 */
+                start = obj->da_start ? obj->da_start : alignment;
+
+                if (flags & IOVMF_LINEAR)
+                        alignment = iopgsz_max(bytes);
+                start = roundup(start, alignment);
+        } else if (start < obj->da_start || start > obj->da_end ||
+                                        obj->da_end - start < bytes) {
+                return ERR_PTR(-EINVAL);
+        }
+
+        tmp = NULL;
+        if (list_empty(&obj->mmap))
+                goto found;
+
+        prev_end = 0;
+        list_for_each_entry(tmp, &obj->mmap, list) {
+
+                if (prev_end > start)
+                        break;
+
+                if (tmp->da_start > start && (tmp->da_start - start) >= bytes)
+                        goto found;
+
+                if (tmp->da_end >= start && ~flags & IOVMF_DA_FIXED)
+                        start = roundup(tmp->da_end + 1, alignment);
+
+                prev_end = tmp->da_end;
+        }
+
+        if ((start >= prev_end) && (obj->da_end - start >= bytes))
+                goto found;
+
+        dev_dbg(obj->dev, "%s: no space to fit %08x(%x) flags: %08x\n",
+                __func__, da, bytes, flags);
+
+        return ERR_PTR(-EINVAL);
+
+found:
+        new = kmem_cache_zalloc(iovm_area_cachep, GFP_KERNEL);
+        if (!new)
+                return ERR_PTR(-ENOMEM);
+
+        new->iommu = obj;
+        new->da_start = start;
+        new->da_end = start + bytes;
+        new->flags = flags;
+
+        /*
+         * keep ascending order of iovmas
+         */
+        if (tmp)
+                list_add_tail(&new->list, &tmp->list);
+        else
+                list_add(&new->list, &obj->mmap);
+
+        dev_dbg(obj->dev, "%s: found %08x-%08x-%08x(%x) %08x\n",
+                __func__, new->da_start, start, new->da_end, bytes, flags);
+
+        return new;
+}
+
+static void free_iovm_area(struct iommu *obj, struct iovm_struct *area)
+{
+        size_t bytes;
+
+        BUG_ON(!obj || !area);
+
+        bytes = area->da_end - area->da_start;
+
+        dev_dbg(obj->dev, "%s: %08x-%08x(%x) %08x\n",
+                __func__, area->da_start, area->da_end, bytes, area->flags);
+
+        list_del(&area->list);
+        kmem_cache_free(iovm_area_cachep, area);
+}
+
+/**
+ * da_to_va - convert (d) to (v)
+ * @obj:        objective iommu
+ * @da:         iommu device virtual address
+ * @va:         mpu virtual address
+ *
+ * Returns mpu virtual addr which corresponds to a given device virtual addr
+ */
+void *da_to_va(struct iommu *obj, u32 da)
+{
+        void *va = NULL;
+        struct iovm_struct *area;
+
+        mutex_lock(&obj->mmap_lock);
+
+        area = __find_iovm_area(obj, da);
+        if (!area) {
+                dev_dbg(obj->dev, "%s: no da area(%08x)\n", __func__, da);
+                goto out;
+        }
+        va = area->va;
+out:
+        mutex_unlock(&obj->mmap_lock);
+
+        return va;
+}
+EXPORT_SYMBOL_GPL(da_to_va);
+
+static void sgtable_fill_vmalloc(struct sg_table *sgt, void *_va)
+{
+        unsigned int i;
+        struct scatterlist *sg;
+        void *va = _va;
+        void *va_end;
+
+        for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+                struct page *pg;
+                const size_t bytes = PAGE_SIZE;
+
+                /*
+                 * iommu 'superpage' isn't supported with 'iommu_vmalloc()'
+                 */
+                pg = vmalloc_to_page(va);
+                BUG_ON(!pg);
+                sg_set_page(sg, pg, bytes, 0);
+
+                va += bytes;
+        }
+
+        va_end = _va + PAGE_SIZE * i;
+}
+
+static inline void sgtable_drain_vmalloc(struct sg_table *sgt)
+{
+        /*
+         * Actually this is not necessary at all, just exists for
+         * consistency of the code readability.
+         */
+        BUG_ON(!sgt);
+}
+
+static void sgtable_fill_kmalloc(struct sg_table *sgt, u32 pa, u32 da,
+                                                                size_t len)
+{
+        unsigned int i;
+        struct scatterlist *sg;
+
+        for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+                unsigned bytes;
+
+                bytes = max_alignment(da | pa);
+                bytes = min_t(unsigned, bytes, iopgsz_max(len));
+
+                BUG_ON(!iopgsz_ok(bytes));
+
+                sg_set_buf(sg, phys_to_virt(pa), bytes);
+                /*
+                 * 'pa' is cotinuous(linear).
+                 */
+                pa += bytes;
+                da += bytes;
+                len -= bytes;
+        }
+        BUG_ON(len);
+}
+
+static inline void sgtable_drain_kmalloc(struct sg_table *sgt)
+{
+        /*
+         * Actually this is not necessary at all, just exists for
+         * consistency of the code readability
+         */
+        BUG_ON(!sgt);
+}
+
+/* create 'da' <-> 'pa' mapping from 'sgt' */
+static int map_iovm_area(struct iommu_domain *domain, struct iovm_struct *new,
+                        const struct sg_table *sgt, u32 flags)
+{
+        int err;
+        unsigned int i, j;
+        struct scatterlist *sg;
+        u32 da = new->da_start;
+        int order;
+
+        if (!domain || !sgt)
+                return -EINVAL;
+
+        BUG_ON(!sgtable_ok(sgt));
+
+        for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+                u32 pa;
+                size_t bytes;
+
+                pa = sg_phys(sg);
+                bytes = sg->length;
+
+                flags &= ~IOVMF_PGSZ_MASK;
+
+                if (bytes_to_iopgsz(bytes) < 0)
+                        goto err_out;
+
+                order = get_order(bytes);
+
+                pr_debug("%s: [%d] %08x %08x(%x)\n", __func__,
+                         i, da, pa, bytes);
+
+                err = iommu_map(domain, da, pa, order, flags);
+                if (err)
+                        goto err_out;
+
+                da += bytes;
+        }
+        return 0;
+
+err_out:
+        da = new->da_start;
+
+        for_each_sg(sgt->sgl, sg, i, j) {
+                size_t bytes;
+
+                bytes = sg->length;
+                order = get_order(bytes);
+
+                /* ignore failures.. we're already handling one */
+                iommu_unmap(domain, da, order);
+
+                da += bytes;
+        }
+        return err;
+}
+
+/* release 'da' <-> 'pa' mapping */
+static void unmap_iovm_area(struct iommu_domain *domain, struct iommu *obj,
+                                                struct iovm_struct *area)
+{
+        u32 start;
+        size_t total = area->da_end - area->da_start;
+        const struct sg_table *sgt = area->sgt;
+        struct scatterlist *sg;
+        int i, err;
+
+        BUG_ON(!sgtable_ok(sgt));
+        BUG_ON((!total) || !IS_ALIGNED(total, PAGE_SIZE));
+
+        start = area->da_start;
+        for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+                size_t bytes;
+                int order;
+
+                bytes = sg->length;
+                order = get_order(bytes);
+
+                err = iommu_unmap(domain, start, order);
+                if (err)
+                        break;
+
+                dev_dbg(obj->dev, "%s: unmap %08x(%x) %08x\n",
+                                __func__, start, bytes, area->flags);
+
+                BUG_ON(!IS_ALIGNED(bytes, PAGE_SIZE));
+
+                total -= bytes;
+                start += bytes;
+        }
+        BUG_ON(total);
+}
+
+/* template function for all unmapping */
+static struct sg_table *unmap_vm_area(struct iommu_domain *domain,
+                                      struct iommu *obj, const u32 da,
+                                      void (*fn)(const void *), u32 flags)
+{
+        struct sg_table *sgt = NULL;
+        struct iovm_struct *area;
+
+        if (!IS_ALIGNED(da, PAGE_SIZE)) {
+                dev_err(obj->dev, "%s: alignment err(%08x)\n", __func__, da);
+                return NULL;
+        }
+
+        mutex_lock(&obj->mmap_lock);
+
+        area = __find_iovm_area(obj, da);
+        if (!area) {
+                dev_dbg(obj->dev, "%s: no da area(%08x)\n", __func__, da);
+                goto out;
+        }
+
+        if ((area->flags & flags) != flags) {
+                dev_err(obj->dev, "%s: wrong flags(%08x)\n", __func__,
+                        area->flags);
+                goto out;
+        }
+        sgt = (struct sg_table *)area->sgt;
+
+        unmap_iovm_area(domain, obj, area);
+
+        fn(area->va);
+
+        dev_dbg(obj->dev, "%s: %08x-%08x-%08x(%x) %08x\n", __func__,
+                area->da_start, da, area->da_end,
+                area->da_end - area->da_start, area->flags);
+
+        free_iovm_area(obj, area);
+out:
+        mutex_unlock(&obj->mmap_lock);
+
+        return sgt;
+}
+
+static u32 map_iommu_region(struct iommu_domain *domain, struct iommu *obj,
+                                u32 da, const struct sg_table *sgt, void *va,
+                                size_t bytes, u32 flags)
+{
+        int err = -ENOMEM;
+        struct iovm_struct *new;
+
+        mutex_lock(&obj->mmap_lock);
+
+        new = alloc_iovm_area(obj, da, bytes, flags);
+        if (IS_ERR(new)) {
+                err = PTR_ERR(new);
+                goto err_alloc_iovma;
+        }
+        new->va = va;
+        new->sgt = sgt;
+
+        if (map_iovm_area(domain, new, sgt, new->flags))
+                goto err_map;
+
+        mutex_unlock(&obj->mmap_lock);
+
+        dev_dbg(obj->dev, "%s: da:%08x(%x) flags:%08x va:%p\n",
+                __func__, new->da_start, bytes, new->flags, va);
+
+        return new->da_start;
+
+err_map:
+        free_iovm_area(obj, new);
+err_alloc_iovma:
+        mutex_unlock(&obj->mmap_lock);
+        return err;
+}
+
+static inline u32 __iommu_vmap(struct iommu_domain *domain, struct iommu *obj,
+                                u32 da, const struct sg_table *sgt,
+                                void *va, size_t bytes, u32 flags)
+{
+        return map_iommu_region(domain, obj, da, sgt, va, bytes, flags);
+}
+
+/**
+ * iommu_vmap  -  (d)-(p)-(v) address mapper
+ * @obj:        objective iommu
+ * @sgt:        address of scatter gather table
+ * @flags:      iovma and page property
+ *
+ * Creates 1-n-1 mapping with given @sgt and returns @da.
+ * All @sgt element must be io page size aligned.
+ */
+u32 iommu_vmap(struct iommu_domain *domain, struct iommu *obj, u32 da,
+                const struct sg_table *sgt, u32 flags)
+{
+        size_t bytes;
+        void *va = NULL;
+
+        if (!obj || !obj->dev || !sgt)
+                return -EINVAL;
+
+        bytes = sgtable_len(sgt);
+        if (!bytes)
+                return -EINVAL;
+        bytes = PAGE_ALIGN(bytes);
+
+        if (flags & IOVMF_MMIO) {
+                va = vmap_sg(sgt);
+                if (IS_ERR(va))
+                        return PTR_ERR(va);
+        }
+
+        flags |= IOVMF_DISCONT;
+        flags |= IOVMF_MMIO;
+
+        da = __iommu_vmap(domain, obj, da, sgt, va, bytes, flags);
+        if (IS_ERR_VALUE(da))
+                vunmap_sg(va);
+
+        return da;
+}
+EXPORT_SYMBOL_GPL(iommu_vmap);
+
+/**
+ * iommu_vunmap  -  release virtual mapping obtained by 'iommu_vmap()'
+ * @obj:        objective iommu
+ * @da:         iommu device virtual address
+ *
+ * Free the iommu virtually contiguous memory area starting at
+ * @da, which was returned by 'iommu_vmap()'.
+ */
+struct sg_table *
+iommu_vunmap(struct iommu_domain *domain, struct iommu *obj, u32 da)
+{
+        struct sg_table *sgt;
+        /*
+         * 'sgt' is allocated before 'iommu_vmalloc()' is called.
+         * Just returns 'sgt' to the caller to free
+         */
+        sgt = unmap_vm_area(domain, obj, da, vunmap_sg,
+                                        IOVMF_DISCONT | IOVMF_MMIO);
+        if (!sgt)
+                dev_dbg(obj->dev, "%s: No sgt\n", __func__);
+        return sgt;
+}
+EXPORT_SYMBOL_GPL(iommu_vunmap);
+
+/**
+ * iommu_vmalloc  -  (d)-(p)-(v) address allocator and mapper
+ * @obj:        objective iommu
+ * @da:         contiguous iommu virtual memory
+ * @bytes:      allocation size
+ * @flags:      iovma and page property
+ *
+ * Allocate @bytes linearly and creates 1-n-1 mapping and returns
+ * @da again, which might be adjusted if 'IOVMF_DA_FIXED' is not set.
+ */
+u32 iommu_vmalloc(struct iommu_domain *domain, struct iommu *obj, u32 da,
+                                                size_t bytes, u32 flags)
+{
+        void *va;
+        struct sg_table *sgt;
+
+        if (!obj || !obj->dev || !bytes)
+                return -EINVAL;
+
+        bytes = PAGE_ALIGN(bytes);
+
+        va = vmalloc(bytes);
+        if (!va)
+                return -ENOMEM;
+
+        flags |= IOVMF_DISCONT;
+        flags |= IOVMF_ALLOC;
+
+        sgt = sgtable_alloc(bytes, flags, da, 0);
+        if (IS_ERR(sgt)) {
+                da = PTR_ERR(sgt);
+                goto err_sgt_alloc;
+        }
+        sgtable_fill_vmalloc(sgt, va);
+
+        da = __iommu_vmap(domain, obj, da, sgt, va, bytes, flags);
+        if (IS_ERR_VALUE(da))
+                goto err_iommu_vmap;
+
+        return da;
+
+err_iommu_vmap:
+        sgtable_drain_vmalloc(sgt);
+        sgtable_free(sgt);
+err_sgt_alloc:
+        vfree(va);
+        return da;
+}
+EXPORT_SYMBOL_GPL(iommu_vmalloc);
+
+/**
+ * iommu_vfree  -  release memory allocated by 'iommu_vmalloc()'
+ * @obj:        objective iommu
+ * @da:         iommu device virtual address
+ *
+ * Frees the iommu virtually continuous memory area starting at
+ * @da, as obtained from 'iommu_vmalloc()'.
+ */
+void iommu_vfree(struct iommu_domain *domain, struct iommu *obj, const u32 da)
+{
+        struct sg_table *sgt;
+
+        sgt = unmap_vm_area(domain, obj, da, vfree,
+                                                IOVMF_DISCONT | IOVMF_ALLOC);
+        if (!sgt)
+                dev_dbg(obj->dev, "%s: No sgt\n", __func__);
+        sgtable_free(sgt);
+}
+EXPORT_SYMBOL_GPL(iommu_vfree);
+
+static u32 __iommu_kmap(struct iommu_domain *domain, struct iommu *obj,
+                        u32 da, u32 pa, void *va, size_t bytes, u32 flags)
+{
+        struct sg_table *sgt;
+
+        sgt = sgtable_alloc(bytes, flags, da, pa);
+        if (IS_ERR(sgt))
+                return PTR_ERR(sgt);
+
+        sgtable_fill_kmalloc(sgt, pa, da, bytes);
+
+        da = map_iommu_region(domain, obj, da, sgt, va, bytes, flags);
+        if (IS_ERR_VALUE(da)) {
+                sgtable_drain_kmalloc(sgt);
+                sgtable_free(sgt);
+        }
+
+        return da;
+}
+
+/**
+ * iommu_kmap  -  (d)-(p)-(v) address mapper
+ * @obj:        objective iommu
+ * @da:         contiguous iommu virtual memory
+ * @pa:         contiguous physical memory
+ * @flags:      iovma and page property
+ *
+ * Creates 1-1-1 mapping and returns @da again, which can be
+ * adjusted if 'IOVMF_DA_FIXED' is not set.
+ */
+u32 iommu_kmap(struct iommu_domain *domain, struct iommu *obj, u32 da, u32 pa,
+                                                size_t bytes, u32 flags)
+{
+        void *va;
+
+        if (!obj || !obj->dev || !bytes)
+                return -EINVAL;
+
+        bytes = PAGE_ALIGN(bytes);
+
+        va = ioremap(pa, bytes);
+        if (!va)
+                return -ENOMEM;
+
+        flags |= IOVMF_LINEAR;
+        flags |= IOVMF_MMIO;
+
+        da = __iommu_kmap(domain, obj, da, pa, va, bytes, flags);
+        if (IS_ERR_VALUE(da))
+                iounmap(va);
+
+        return da;
+}
+EXPORT_SYMBOL_GPL(iommu_kmap);
+
+/**
+ * iommu_kunmap  -  release virtual mapping obtained by 'iommu_kmap()'
+ * @obj:        objective iommu
+ * @da:         iommu device virtual address
+ *
+ * Frees the iommu virtually contiguous memory area starting at
+ * @da, which was passed to and was returned by'iommu_kmap()'.
+ */
+void iommu_kunmap(struct iommu_domain *domain, struct iommu *obj, u32 da)
+{
+        struct sg_table *sgt;
+        typedef void (*func_t)(const void *);
+
+        sgt = unmap_vm_area(domain, obj, da, (func_t)iounmap,
+                            IOVMF_LINEAR | IOVMF_MMIO);
+        if (!sgt)
+                dev_dbg(obj->dev, "%s: No sgt\n", __func__);
+        sgtable_free(sgt);
+}
+EXPORT_SYMBOL_GPL(iommu_kunmap);
+
+/**
+ * iommu_kmalloc  -  (d)-(p)-(v) address allocator and mapper
+ * @obj:        objective iommu
+ * @da:         contiguous iommu virtual memory
+ * @bytes:      bytes for allocation
+ * @flags:      iovma and page property
+ *
+ * Allocate @bytes linearly and creates 1-1-1 mapping and returns
+ * @da again, which might be adjusted if 'IOVMF_DA_FIXED' is not set.
+ */
+u32 iommu_kmalloc(struct iommu_domain *domain, struct iommu *obj, u32 da,
+                                                size_t bytes, u32 flags)
+{
+        void *va;
+        u32 pa;
+
+        if (!obj || !obj->dev || !bytes)
+                return -EINVAL;
+
+        bytes = PAGE_ALIGN(bytes);
+
+        va = kmalloc(bytes, GFP_KERNEL | GFP_DMA);
+        if (!va)
+                return -ENOMEM;
+        pa = virt_to_phys(va);
+
+        flags |= IOVMF_LINEAR;
+        flags |= IOVMF_ALLOC;
+
+        da = __iommu_kmap(domain, obj, da, pa, va, bytes, flags);
+        if (IS_ERR_VALUE(da))
+                kfree(va);
+
+        return da;
+}
+EXPORT_SYMBOL_GPL(iommu_kmalloc);
+
+/**
+ * iommu_kfree  -  release virtual mapping obtained by 'iommu_kmalloc()'
+ * @obj:        objective iommu
+ * @da:         iommu device virtual address
+ *
+ * Frees the iommu virtually contiguous memory area starting at
+ * @da, which was passed to and was returned by'iommu_kmalloc()'.
+ */
+void iommu_kfree(struct iommu_domain *domain, struct iommu *obj, u32 da)
+{
+        struct sg_table *sgt;
+
+        sgt = unmap_vm_area(domain, obj, da, kfree, IOVMF_LINEAR | IOVMF_ALLOC);
+        if (!sgt)
+                dev_dbg(obj->dev, "%s: No sgt\n", __func__);
+        sgtable_free(sgt);
+}
+EXPORT_SYMBOL_GPL(iommu_kfree);
+
+
+static int __init iovmm_init(void)
+{
+        const unsigned long flags = SLAB_HWCACHE_ALIGN;
+        struct kmem_cache *p;
+
+        p = kmem_cache_create("iovm_area_cache", sizeof(struct iovm_struct), 0,
+                              flags, NULL);
+        if (!p)
+                return -ENOMEM;
+        iovm_area_cachep = p;
+
+        return 0;
+}
+module_init(iovmm_init);
+
+static void __exit iovmm_exit(void)
+{
+        kmem_cache_destroy(iovm_area_cachep);
+}
+module_exit(iovmm_exit);
+
+MODULE_DESCRIPTION("omap iommu: simple virtual address space management");
+MODULE_AUTHOR("Hiroshi DOYU <Hiroshi.DOYU@nokia.com>");
+MODULE_LICENSE("GPL v2");