Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=0291df8cc9dac09c303d21d5bcd2ad73762c836a
Commit:     0291df8cc9dac09c303d21d5bcd2ad73762c836a
Parent:     0c95fdc59640824d7e0b017be295fb912ceef4ab
Author:     FUJITA Tomonori <[EMAIL PROTECTED]>
AuthorDate: Mon Feb 4 22:28:07 2008 -0800
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Tue Feb 5 09:44:11 2008 -0800

    iommu sg: add IOMMU helper functions for the free area management
    
    This adds IOMMU helper functions for the free area management.  These
    functions take care of LLD's segment boundary limit for IOMMUs.  They would 
be
    useful for IOMMUs that use bitmap for the free area management.
    
    Signed-off-by: FUJITA Tomonori <[EMAIL PROTECTED]>
    Cc: Jeff Garzik <[EMAIL PROTECTED]>
    Cc: James Bottomley <[EMAIL PROTECTED]>
    Cc: Jens Axboe <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
 include/linux/iommu-helper.h |    7 ++++
 lib/Makefile                 |    1 +
 lib/iommu-helper.c           |   80 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+), 0 deletions(-)

diff --git a/include/linux/iommu-helper.h b/include/linux/iommu-helper.h
new file mode 100644
index 0000000..4dd4c04
--- /dev/null
+++ b/include/linux/iommu-helper.h
@@ -0,0 +1,7 @@
+extern unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
+                                     unsigned long start, unsigned int nr,
+                                     unsigned long shift,
+                                     unsigned long boundary_size,
+                                     unsigned long align_mask);
+extern void iommu_area_free(unsigned long *map, unsigned long start,
+                           unsigned int nr);
diff --git a/lib/Makefile b/lib/Makefile
index 543f250..a18062e 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_SMP) += pcounter.o
 obj-$(CONFIG_AUDIT_GENERIC) += audit.o
 
 obj-$(CONFIG_SWIOTLB) += swiotlb.o
+obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o
 obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o
 
 lib-$(CONFIG_GENERIC_BUG) += bug.o
diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c
new file mode 100644
index 0000000..495575a
--- /dev/null
+++ b/lib/iommu-helper.c
@@ -0,0 +1,80 @@
+/*
+ * IOMMU helper functions for the free area management
+ */
+
+#include <linux/module.h>
+#include <linux/bitops.h>
+
+static unsigned long find_next_zero_area(unsigned long *map,
+                                        unsigned long size,
+                                        unsigned long start,
+                                        unsigned int nr,
+                                        unsigned long align_mask)
+{
+       unsigned long index, end, i;
+again:
+       index = find_next_zero_bit(map, size, start);
+
+       /* Align allocation */
+       index = (index + align_mask) & ~align_mask;
+
+       end = index + nr;
+       if (end >= size)
+               return -1;
+       for (i = index; i < end; i++) {
+               if (test_bit(i, map)) {
+                       start = i+1;
+                       goto again;
+               }
+       }
+       return index;
+}
+
+static inline void set_bit_area(unsigned long *map, unsigned long i,
+                               int len)
+{
+       unsigned long end = i + len;
+       while (i < end) {
+               __set_bit(i, map);
+               i++;
+       }
+}
+
+static inline int is_span_boundary(unsigned int index, unsigned int nr,
+                                  unsigned long shift,
+                                  unsigned long boundary_size)
+{
+       shift = (shift + index) & (boundary_size - 1);
+       return shift + nr > boundary_size;
+}
+
+unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
+                              unsigned long start, unsigned int nr,
+                              unsigned long shift, unsigned long boundary_size,
+                              unsigned long align_mask)
+{
+       unsigned long index;
+again:
+       index = find_next_zero_area(map, size, start, nr, align_mask);
+       if (index != -1) {
+               if (is_span_boundary(index, nr, shift, boundary_size)) {
+                       /* we could do more effectively */
+                       start = index + 1;
+                       goto again;
+               }
+               set_bit_area(map, index, nr);
+       }
+       return index;
+}
+EXPORT_SYMBOL(iommu_area_alloc);
+
+void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr)
+{
+       unsigned long end = start + nr;
+
+       while (start < end) {
+               __clear_bit(start, map);
+               start++;
+       }
+}
+EXPORT_SYMBOL(iommu_area_free);
-
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