42 lines
1.0 KiB
C
42 lines
1.0 KiB
C
/*
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* IOMMU helper functions for the free area management
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*/
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#include <linux/export.h>
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#include <linux/bitmap.h>
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#include <linux/bug.h>
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int iommu_is_span_boundary(unsigned int index, unsigned int nr,
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unsigned long shift,
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unsigned long boundary_size)
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{
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BUG_ON(!is_power_of_2(boundary_size));
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shift = (shift + index) & (boundary_size - 1);
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return shift + nr > boundary_size;
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}
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unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
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unsigned long start, unsigned int nr,
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unsigned long shift, unsigned long boundary_size,
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unsigned long align_mask)
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{
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unsigned long index;
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/* We don't want the last of the limit */
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size -= 1;
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again:
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index = bitmap_find_next_zero_area(map, size, start, nr, align_mask);
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if (index < size) {
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if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
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/* we could do more effectively */
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start = index + 1;
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goto again;
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}
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bitmap_set(map, index, nr);
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return index;
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}
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return -1;
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}
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EXPORT_SYMBOL(iommu_area_alloc);
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