Line data    Source code

       1             : /*
       2             :  * IOMMU helper functions for the free area management
       3             :  */
       4             : 
       5             : #include <linux/export.h>
       6             : #include <linux/bitmap.h>
       7             : #include <linux/bug.h>
       8             : 
       9           0 : int iommu_is_span_boundary(unsigned int index, unsigned int nr,
      10             :                            unsigned long shift,
      11             :                            unsigned long boundary_size)
      12             : {
      13             :         BUG_ON(!is_power_of_2(boundary_size));
      14             : 
      15           0 :         shift = (shift + index) & (boundary_size - 1);
      16           0 :         return shift + nr > boundary_size;
      17             : }
      18             : 
      19           0 : unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
      20             :                                unsigned long start, unsigned int nr,
      21             :                                unsigned long shift, unsigned long boundary_size,
      22             :                                unsigned long align_mask)
      23             : {
      24             :         unsigned long index;
      25             : 
      26             :         /* We don't want the last of the limit */
      27           0 :         size -= 1;
      28             : again:
      29             :         index = bitmap_find_next_zero_area(map, size, start, nr, align_mask);
      30           0 :         if (index < size) {
      31           0 :                 if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
      32             :                         /* we could do more effectively */
      33           0 :                         start = index + 1;
      34           0 :                         goto again;
      35             :                 }
      36           0 :                 bitmap_set(map, index, nr);
      37           0 :                 return index;
      38             :         }
      39             :         return -1;
      40             : }
      41             : EXPORT_SYMBOL(iommu_area_alloc);