diff --git a/include/linux/iommu-common.h b/include/linux/iommu-common.h
new file mode 100644
index 0000000000000000000000000000000000000000..bbced83b32ee1c45da17450f34fa16a26ec3092a
--- /dev/null
+++ b/include/linux/iommu-common.h
@@ -0,0 +1,51 @@
+#ifndef _LINUX_IOMMU_COMMON_H
+#define _LINUX_IOMMU_COMMON_H
+
+#include <linux/spinlock_types.h>
+#include <linux/device.h>
+#include <asm/page.h>
+
+#define IOMMU_POOL_HASHBITS 4
+#define IOMMU_NR_POOLS (1 << IOMMU_POOL_HASHBITS)
+
+struct iommu_pool {
+ unsigned long start;
+ unsigned long end;
+ unsigned long hint;
+ spinlock_t lock;
+};
+
+struct iommu_map_table {
+ unsigned long table_map_base;
+ unsigned long table_shift;
+ unsigned long nr_pools;
+ void (*lazy_flush)(struct iommu_map_table *);
+ unsigned long poolsize;
+ struct iommu_pool pools[IOMMU_NR_POOLS];
+ u32 flags;
+#define IOMMU_HAS_LARGE_POOL 0x00000001
+#define IOMMU_NO_SPAN_BOUND 0x00000002
+#define IOMMU_NEED_FLUSH 0x00000004
+ struct iommu_pool large_pool;
+ unsigned long *map;
+};
+
+extern void iommu_tbl_pool_init(struct iommu_map_table *iommu,
+ unsigned long num_entries,
+ u32 table_shift,
+ void (*lazy_flush)(struct iommu_map_table *),
+ bool large_pool, u32 npools,
+ bool skip_span_boundary_check);
+
+extern unsigned long iommu_tbl_range_alloc(struct device *dev,
+ struct iommu_map_table *iommu,
+ unsigned long npages,
+ unsigned long *handle,
+ unsigned long mask,
+ unsigned int align_order);
+
+extern void iommu_tbl_range_free(struct iommu_map_table *iommu,
+ u64 dma_addr, unsigned long npages,
+ unsigned long entry);
+
+#endif
diff --git a/lib/Makefile b/lib/Makefile
index da6116b21555583864e2eadd7ae5615d46878d84..6c37933336a0261007f73e8511936e95ff1f514c 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -106,7 +106,7 @@ obj-$(CONFIG_AUDIT_GENERIC) += audit.o
obj-$(CONFIG_AUDIT_COMPAT_GENERIC) += compat_audit.o
obj-$(CONFIG_SWIOTLB) += swiotlb.o
-obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o
+obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o iommu-common.o
obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o
obj-$(CONFIG_NOTIFIER_ERROR_INJECTION) += notifier-error-inject.o
obj-$(CONFIG_CPU_NOTIFIER_ERROR_INJECT) += cpu-notifier-error-inject.o
diff --git a/lib/iommu-common.c b/lib/iommu-common.c
new file mode 100644
index 0000000000000000000000000000000000000000..b99f1d744a8dd67e6b7d7961b6e3cfbb8a07c381
--- /dev/null
+++ b/lib/iommu-common.c
@@ -0,0 +1,266 @@
+/*
+ * IOMMU mmap management and range allocation functions.
+ * Based almost entirely upon the powerpc iommu allocator.
+ */
+
+#include <linux/export.h>
+#include <linux/bitmap.h>
+#include <linux/bug.h>
+#include <linux/iommu-helper.h>
+#include <linux/iommu-common.h>
+#include <linux/dma-mapping.h>
+#include <linux/hash.h>
+
+unsigned long iommu_large_alloc = 15;
+
+static DEFINE_PER_CPU(unsigned int, iommu_pool_hash);
+
+static inline bool need_flush(struct iommu_map_table *iommu)
+{
+ return (iommu->lazy_flush != NULL &&
+ (iommu->flags & IOMMU_NEED_FLUSH) != 0);
+}
+
+static inline void set_flush(struct iommu_map_table *iommu)
+{
+ iommu->flags |= IOMMU_NEED_FLUSH;
+}
+
+static inline void clear_flush(struct iommu_map_table *iommu)
+{
+ iommu->flags &= ~IOMMU_NEED_FLUSH;
+}
+
+static void setup_iommu_pool_hash(void)
+{
+ unsigned int i;
+ static bool do_once;
+
+ if (do_once)
+ return;
+ do_once = true;
+ for_each_possible_cpu(i)
+ per_cpu(iommu_pool_hash, i) = hash_32(i, IOMMU_POOL_HASHBITS);
+}
+
+/*
+ * Initialize iommu_pool entries for the iommu_map_table. `num_entries'
+ * is the number of table entries. If `large_pool' is set to true,
+ * the top 1/4 of the table will be set aside for pool allocations
+ * of more than iommu_large_alloc pages.
+ */
+extern void iommu_tbl_pool_init(struct iommu_map_table *iommu,
+ unsigned long num_entries,
+ u32 table_shift,
+ void (*lazy_flush)(struct iommu_map_table *),
+ bool large_pool, u32 npools,
+ bool skip_span_boundary_check)
+{
+ unsigned int start, i;
+ struct iommu_pool *p = &(iommu->large_pool);
+
+ setup_iommu_pool_hash();
+ if (npools == 0)
+ iommu->nr_pools = IOMMU_NR_POOLS;
+ else
+ iommu->nr_pools = npools;
+ BUG_ON(npools > IOMMU_NR_POOLS);
+
+ iommu->table_shift = table_shift;
+ iommu->lazy_flush = lazy_flush;
+ start = 0;
+ if (skip_span_boundary_check)
+ iommu->flags |= IOMMU_NO_SPAN_BOUND;
+ if (large_pool)
+ iommu->flags |= IOMMU_HAS_LARGE_POOL;
+
+ if (!large_pool)
+ iommu->poolsize = num_entries/iommu->nr_pools;
+ else
+ iommu->poolsize = (num_entries * 3 / 4)/iommu->nr_pools;
+ for (i = 0; i < iommu->nr_pools; i++) {
+ spin_lock_init(&(iommu->pools[i].lock));
+ iommu->pools[i].start = start;
+ iommu->pools[i].hint = start;
+ start += iommu->poolsize; /* start for next pool */
+ iommu->pools[i].end = start - 1;
+ }
+ if (!large_pool)
+ return;
+ /* initialize large_pool */
+ spin_lock_init(&(p->lock));
+ p->start = start;
+ p->hint = p->start;
+ p->end = num_entries;
+}
+EXPORT_SYMBOL(iommu_tbl_pool_init);
+
+unsigned long iommu_tbl_range_alloc(struct device *dev,
+ struct iommu_map_table *iommu,
+ unsigned long npages,
+ unsigned long *handle,
+ unsigned long mask,
+ unsigned int align_order)
+{
+ unsigned int pool_hash = __this_cpu_read(iommu_pool_hash);
+ unsigned long n, end, start, limit, boundary_size;
+ struct iommu_pool *pool;
+ int pass = 0;
+ unsigned int pool_nr;
+ unsigned int npools = iommu->nr_pools;
+ unsigned long flags;
+ bool large_pool = ((iommu->flags & IOMMU_HAS_LARGE_POOL) != 0);
+ bool largealloc = (large_pool && npages > iommu_large_alloc);
+ unsigned long shift;
+ unsigned long align_mask = 0;
+
+ if (align_order > 0)
+ align_mask = 0xffffffffffffffffl >> (64 - align_order);
+
+ /* Sanity check */
+ if (unlikely(npages == 0)) {
+ WARN_ON_ONCE(1);
+ return DMA_ERROR_CODE;
+ }
+
+ if (largealloc) {
+ pool = &(iommu->large_pool);
+ pool_nr = 0; /* to keep compiler happy */
+ } else {
+ /* pick out pool_nr */
+ pool_nr = pool_hash & (npools - 1);
+ pool = &(iommu->pools[pool_nr]);
+ }
+ spin_lock_irqsave(&pool->lock, flags);
+
+ again:
+ if (pass == 0 && handle && *handle &&
+ (*handle >= pool->start) && (*handle < pool->end))
+ start = *handle;
+ else
+ start = pool->hint;
+
+ limit = pool->end;
+
+ /* The case below can happen if we have a small segment appended
+ * to a large, or when the previous alloc was at the very end of
+ * the available space. If so, go back to the beginning. If a
+ * flush is needed, it will get done based on the return value
+ * from iommu_area_alloc() below.
+ */
+ if (start >= limit)
+ start = pool->start;
+ shift = iommu->table_map_base >> iommu->table_shift;
+ if (limit + shift > mask) {
+ limit = mask - shift + 1;
+ /* If we're constrained on address range, first try
+ * at the masked hint to avoid O(n) search complexity,
+ * but on second pass, start at 0 in pool 0.
+ */
+ if ((start & mask) >= limit || pass > 0) {
+ spin_unlock(&(pool->lock));
+ pool = &(iommu->pools[0]);
+ spin_lock(&(pool->lock));
+ start = pool->start;
+ } else {
+ start &= mask;
+ }
+ }
+
+ if (dev)
+ boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
+ 1 << iommu->table_shift);
+ else
+ boundary_size = ALIGN(1UL << 32, 1 << iommu->table_shift);
+
+ boundary_size = boundary_size >> iommu->table_shift;
+ /*
+ * if the skip_span_boundary_check had been set during init, we set
+ * things up so that iommu_is_span_boundary() merely checks if the
+ * (index + npages) < num_tsb_entries
+ */
+ if ((iommu->flags & IOMMU_NO_SPAN_BOUND) != 0) {
+ shift = 0;
+ boundary_size = iommu->poolsize * iommu->nr_pools;
+ }
+ n = iommu_area_alloc(iommu->map, limit, start, npages, shift,
+ boundary_size, align_mask);
+ if (n == -1) {
+ if (likely(pass == 0)) {
+ /* First failure, rescan from the beginning. */
+ pool->hint = pool->start;
+ set_flush(iommu);
+ pass++;
+ goto again;
+ } else if (!largealloc && pass <= iommu->nr_pools) {
+ spin_unlock(&(pool->lock));
+ pool_nr = (pool_nr + 1) & (iommu->nr_pools - 1);
+ pool = &(iommu->pools[pool_nr]);
+ spin_lock(&(pool->lock));
+ pool->hint = pool->start;
+ set_flush(iommu);
+ pass++;
+ goto again;
+ } else {
+ /* give up */
+ n = DMA_ERROR_CODE;
+ goto bail;
+ }
+ }
+ if (n < pool->hint || need_flush(iommu)) {
+ clear_flush(iommu);
+ iommu->lazy_flush(iommu);
+ }
+
+ end = n + npages;
+ pool->hint = end;
+
+ /* Update handle for SG allocations */
+ if (handle)
+ *handle = end;
+bail:
+ spin_unlock_irqrestore(&(pool->lock), flags);
+
+ return n;
+}
+EXPORT_SYMBOL(iommu_tbl_range_alloc);
+
+static struct iommu_pool *get_pool(struct iommu_map_table *tbl,
+ unsigned long entry)
+{
+ struct iommu_pool *p;
+ unsigned long largepool_start = tbl->large_pool.start;
+ bool large_pool = ((tbl->flags & IOMMU_HAS_LARGE_POOL) != 0);
+
+ /* The large pool is the last pool at the top of the table */
+ if (large_pool && entry >= largepool_start) {
+ p = &tbl->large_pool;
+ } else {
+ unsigned int pool_nr = entry / tbl->poolsize;
+
+ BUG_ON(pool_nr >= tbl->nr_pools);
+ p = &tbl->pools[pool_nr];
+ }
+ return p;
+}
+
+/* Caller supplies the index of the entry into the iommu map table
+ * itself when the mapping from dma_addr to the entry is not the
+ * default addr->entry mapping below.
+ */
+void iommu_tbl_range_free(struct iommu_map_table *iommu, u64 dma_addr,
+ unsigned long npages, unsigned long entry)
+{
+ struct iommu_pool *pool;
+ unsigned long flags;
+ unsigned long shift = iommu->table_shift;
+
+ if (entry == DMA_ERROR_CODE) /* use default addr->entry mapping */
+ entry = (dma_addr - iommu->table_map_base) >> shift;
+ pool = get_pool(iommu, entry);
+
+ spin_lock_irqsave(&(pool->lock), flags);
+ bitmap_clear(iommu->map, entry, npages);
+ spin_unlock_irqrestore(&(pool->lock), flags);
+}
+EXPORT_SYMBOL(iommu_tbl_range_free);