Merge branch 'iommu-generic-allocator'

Sowmini Varadhan says:

====================
Generic IOMMU pooled allocator

Investigation of network performance on Sparc shows a high
degree of locking contention in the IOMMU allocator, and it
was noticed that the PowerPC code has a better locking model.

This patch series tries to extract the generic parts of the
PowerPC code so that it can be shared across multiple PCI
devices and architectures.

v10: resend patchv9 without RFC tag, and a new mail Message-Id,
(previous non-RFC attempt did not show up on the patchwork queue?)

Full revision history below:
v2 changes:
  - incorporate David Miller editorial comments: sparc specific
    fields moved from iommu-common into sparc's iommu_64.h
  - make the npools value an input parameter, for the case when
    the iommu map size is not very large
  - cookie_to_index mapping, and optimizations for span-boundary
    check, for use case such as LDC.

v3: eliminate iommu_sparc, rearrange the ->demap indirection to
    be invoked under the pool lock.

v4: David Miller review changes:
  - s/IOMMU_ERROR_CODE/DMA_ERROR_CODE
  - page_table_map_base and page_table_shift are unsigned long, not u32.

v5: removed ->cookie_to_index and ->demap indirection from the
    iommu_tbl_ops The caller needs to call these functions as needed,
    before invoking the generic arena allocator functions.
    Added the "skip_span_boundary" argument to iommu_tbl_pool_init() for
    those callers like LDC which do no care about span boundary checks.

v6: removed iommu_tbl_ops, and instead pass the ->flush_all as
    an indirection to iommu_tbl_pool_init(); only invoke ->flush_all
    when there is no large_pool, based on the assumption that large-pool
    usage is infrequently encountered

v7: moved pool_hash initialization to lib/iommu-common.c and cleaned up
    code duplication from sun4v/sun4u/ldc.

v8: Addresses BenH comments with one exception: I've left the
    IOMMU_POOL_HASH as is, so that powerpc can tailor it to their
    convenience.  Discard trylock for simple spin_lock to acquire pool

v9: Addresses latest BenH comments: need_flush checks, add support
    for dma mask and align_order.

v10: resend without RFC tag, and new mail Message-Id.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 51 insertions, 0 deletions

diff --git a/include/linux/iommu-common.h b/include/linux/iommu-common.h
new file mode 100644
index 000000000000..bbced83b32ee
--- /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