81 lines
1.7 KiB
C
81 lines
1.7 KiB
C
/*
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* IOMMU helper functions for the free area management
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*/
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#include <linux/module.h>
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#include <linux/bitops.h>
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static unsigned long find_next_zero_area(unsigned long *map,
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unsigned long size,
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unsigned long start,
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unsigned int nr,
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unsigned long align_mask)
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{
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unsigned long index, end, i;
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again:
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index = find_next_zero_bit(map, size, start);
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/* Align allocation */
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index = (index + align_mask) & ~align_mask;
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end = index + nr;
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if (end >= size)
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return -1;
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for (i = index; i < end; i++) {
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if (test_bit(i, map)) {
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start = i+1;
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goto again;
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}
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}
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return index;
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}
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static inline void set_bit_area(unsigned long *map, unsigned long i,
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int len)
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{
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unsigned long end = i + len;
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while (i < end) {
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__set_bit(i, map);
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i++;
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}
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}
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static inline int 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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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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again:
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index = find_next_zero_area(map, size, start, nr, align_mask);
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if (index != -1) {
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if (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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set_bit_area(map, index, nr);
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}
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return index;
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}
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EXPORT_SYMBOL(iommu_area_alloc);
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void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr)
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{
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unsigned long end = start + nr;
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while (start < end) {
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__clear_bit(start, map);
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start++;
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}
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}
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EXPORT_SYMBOL(iommu_area_free);
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