memrange: Add support for stealing required memory from given ranges
This change adds memranges_steal() which allows the user
to steal memory from the list of available ranges by providing a set
of constraints (limit, size, alignment, tag). It tries to find the
first big enough range that can satisfy the constraints, creates a
hole as per the request and returns base of the stolen memory.
BUG=b:149186922
Signed-off-by: Furquan Shaikh <furquan@google.com>
Change-Id: Ibe9cfae18fc6101ab2e7e27233e45324c8117708
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39484
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/src/lib/memrange.c b/src/lib/memrange.c
index 21fff00..b9c09e8 100644
--- a/src/lib/memrange.c
+++ b/src/lib/memrange.c
@@ -391,3 +391,58 @@
{
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;
+}