diff --git a/src/include/memrange.h b/src/include/memrange.h index 0d20236d61..f8fa033cee 100644 --- a/src/include/memrange.h +++ b/src/include/memrange.h @@ -16,6 +16,7 @@ #define MEMRANGE_H_ #include +#include /* A memranges structure consists of a list of range_entry(s). The structure * is exposed so that a memranges can be used on the stack if needed. */ @@ -166,4 +167,18 @@ void memranges_update_tag(struct memranges *ranges, unsigned long old_tag, /* Returns next entry after the provided entry. NULL if r is last. */ struct range_entry *memranges_next_entry(struct memranges *ranges, const struct range_entry *r); + +/* Steals memory from the available list in given ranges as per the constraints: + * limit = Upper bound for the memory range to steal. + * size = Requested size for the stolen memory. + * align = Alignment requirements for the starting address of the stolen memory. + * (Alignment must be a power of 2). + * tag = Use a range that matches the given tag. + * + * If the constraints can be satisfied, this function creates a hole in the memrange, + * writes the base address of that hole to stolen_base and returns true. Otherwise it returns + * false. */ +bool memranges_steal(struct memranges *ranges, resource_t limit, resource_t size, size_t align, + unsigned long tag, resource_t *stolen_base); + #endif /* MEMRANGE_H_ */ diff --git a/src/lib/memrange.c b/src/lib/memrange.c index 21fff003a1..b9c09e8782 100644 --- a/src/lib/memrange.c +++ b/src/lib/memrange.c @@ -391,3 +391,58 @@ struct range_entry *memranges_next_entry(struct memranges *ranges, { return r->next; } + +/* Find a range entry that satisfies the given constraints to fit a hole that matches the + * required alignment, is big enough, does not exceed the limit and has a matching tag. */ +static const struct range_entry *memranges_find_entry(struct memranges *ranges, + resource_t limit, resource_t size, + size_t align, unsigned long tag) +{ + const struct range_entry *r; + resource_t base, end; + + if (size == 0) + return NULL; + + if (!IS_POWER_OF_2(align)) + return NULL; + + if (!IS_ALIGNED(align, ranges->align)) + return NULL; + + memranges_each_entry(r, ranges) { + + if (r->tag != tag) + continue; + + base = ALIGN_UP(r->begin, align); + end = base + size - 1; + + if (end > r->end) + continue; + + if (end > limit) + continue; + + return r; + } + + return NULL; +} + +bool memranges_steal(struct memranges *ranges, resource_t limit, resource_t size, size_t align, + unsigned long tag, resource_t *stolen_base) +{ + resource_t base; + const struct range_entry *r = memranges_find_entry(ranges, limit, size, align, tag); + + if (r == NULL) + return false; + + base = ALIGN_UP(r->begin, align); + + memranges_create_hole(ranges, base, size); + *stolen_base = base; + + return true; +}