lib: add memrange infrastructure

The memrange infrastructure allows for keeping track of the
machine's physical address space. Each memory_range entry in
a memory_ranges structure can be tagged with an arbitrary value.
It supports merging and deleting ranges as well as filling in
holes in the address space with a particular tag.

The memrange infrastructure will serve as a shared implementation
for address tracking by the MTRR and coreboot mem table code.

Change-Id: Id5bea9d2a419114fca55c59af0fdca063551110e
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2888
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

2 files changed, 324 insertions, 0 deletions

diff --git a/src/lib/Makefile.inc b/src/lib/Makefile.inc
index 02c42a8626..9d3588ea60 100644
--- a/src/lib/Makefile.inc
+++ b/src/lib/Makefile.inc
@@ -86,6 +86,7 @@ ramstage-$(CONFIG_TRACE) += trace.c
 ramstage-$(CONFIG_COLLECT_TIMESTAMPS) += timestamp.c
 ramstage-$(CONFIG_COVERAGE) += libgcov.c
 ramstage-$(CONFIG_MAINBOARD_DO_NATIVE_VGA_INIT) += edid.c
+ramstage-y += memrange.c
 
 # The CBMEM implementations are chosen based on CONFIG_DYNAMIC_CBMEM.
 ifeq ($(CONFIG_DYNAMIC_CBMEM),y)
diff --git a/src/lib/memrange.c b/src/lib/memrange.c
new file mode 100644
index 0000000000..c376d52816
--- /dev/null
+++ b/src/lib/memrange.c
@@ -0,0 +1,323 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2013 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include <stdlib.h>
+#include <console/console.h>
+#include <memrange.h>
+
+/* Coreboot doesn't have a free() function. Therefore, keep a cache of
+ * free'd entries.  */
+static struct range_entry *free_list;
+
+static inline void range_entry_link(struct range_entry **prev_ptr,
+                                    struct range_entry *r)
+{
+	r->next = *prev_ptr;
+	*prev_ptr = r;
+}
+
+static inline void range_entry_unlink(struct range_entry **prev_ptr,
+                                      struct range_entry *r)
+{
+	*prev_ptr = r->next;
+	r->next = NULL;
+}
+
+static inline void range_entry_unlink_and_free(struct range_entry **prev_ptr,
+                                               struct range_entry *r)
+{
+	range_entry_unlink(prev_ptr, r);
+	range_entry_link(&free_list, r);
+}
+
+static struct range_entry *alloc_range(void)
+{
+	if (free_list != NULL) {
+		struct range_entry *r;
+
+		r = free_list;
+		range_entry_unlink(&free_list, r);
+		return r;
+	}
+	return malloc(sizeof(struct range_entry));
+}
+
+static inline struct range_entry *
+range_list_add(struct range_entry **prev_ptr, resource_t begin, resource_t end,
+               unsigned long tag)
+{
+	struct range_entry *new_entry;
+
+	new_entry = alloc_range();
+	if (new_entry == NULL) {
+		printk(BIOS_ERR, "Could not allocate range_entry!\n");
+		return NULL;
+	}
+	new_entry->begin = begin;
+	new_entry->end = end;
+	new_entry->tag = tag;
+	range_entry_link(prev_ptr, new_entry);
+
+	return new_entry;
+}
+
+static void merge_neighbor_entries(struct memranges *ranges)
+{
+	struct range_entry *cur;
+	struct range_entry *prev;
+
+	prev = NULL;
+	/* Merge all neighbors and delete/free the leftover entry. */
+	for (cur = ranges->entries; cur != NULL; cur = cur->next) {
+		/* First entry. Just set prev. */
+		if (prev == NULL) {
+			prev = cur;
+			continue;
+		}
+
+		/* If the previous entry merges with the current update the
+		 * previous entry to cover full range and delete current from
+		 * the list. */
+		if (prev->end + 1 >= cur->begin && prev->tag == cur->tag) {
+			prev->end = cur->end;
+			range_entry_unlink_and_free(&prev->next, cur);
+			/* Set cur to prev so cur->next is valid since cur
+			 * was just unlinked and free. */
+			cur = prev;
+			continue;
+		}
+
+		prev = cur;
+	}
+}
+
+static void remove_memranges(struct memranges *ranges,
+                             resource_t begin, resource_t end,
+                             unsigned long unused)
+{
+	struct range_entry *cur;
+	struct range_entry *next;
+	struct range_entry **prev_ptr;
+
+	prev_ptr = &ranges->entries;
+	for (cur = ranges->entries; cur != NULL; cur = next) {
+		resource_t tmp_end;
+
+		/* Cache the next value to handle unlinks. */
+		next = cur->next;
+
+		/* No other ranges are affected. */
+		if (end < cur->begin)
+			break;
+
+		/* The removal range starts after this one. */
+		if (begin > cur->end) {
+			prev_ptr = &cur->next;
+			continue;
+		}
+
+		/* The removal range overlaps with the current entry either
+		 * partially or fully. However, we need to adjust the removal
+		 * range for any holes. */
+		if (begin <= cur->begin) {
+			begin = cur->begin;
+
+			/* Full removal. */
+			if (end >= cur->end) {
+				begin = cur->end + 1;
+				range_entry_unlink_and_free(prev_ptr, cur);
+				continue;
+			}
+		}
+
+		/* prev_ptr can be set now that the unlink path wasn't taken. */
+		prev_ptr = &cur->next;
+
+		/* Clip the end fragment to do proper splitting. */
+		tmp_end = end;
+		if (end > cur->end)
+			tmp_end = cur->end;
+
+		/* Hole punched in middle of entry. */
+		if (begin > cur->begin && tmp_end < cur->end) {
+			range_list_add(&cur->next, end + 1, cur->end, cur->tag);
+			cur->end = begin - 1;
+			break;
+		}
+
+		/* Removal at beginning. */
+		if (begin == cur->begin)
+			cur->begin = tmp_end + 1;
+
+		/* Removal at end. */
+		if (tmp_end == cur->end)
+			cur->end = begin - 1;
+	}
+}
+
+static void merge_add_memranges(struct memranges *ranges,
+                                   resource_t begin, resource_t end,
+                                   unsigned long tag)
+{
+	struct range_entry *cur;
+	struct range_entry **prev_ptr;
+
+	prev_ptr = &ranges->entries;
+
+	/* Remove all existing entries covered by the range. */
+	remove_memranges(ranges, begin, end, -1);
+
+	/* Find the entry to place the new entry after. Since
+	 * remove_memranges() was called above there is a guranteed
+	 * spot for this new entry. */
+	for (cur = ranges->entries; cur != NULL; cur = cur->next) {
+		/* Found insertion spot before current entry. */
+		if (end < cur->begin)
+			break;
+
+		/* Keep track of previous entry to insert new entry after it. */
+		prev_ptr = &cur->next;
+
+		/* The new entry starts after this one. */
+		if (begin > cur->end)
+			continue;
+
+	}
+
+	/* Add new entry and merge with neighbors. */
+	range_list_add(prev_ptr, begin, end, tag);
+	merge_neighbor_entries(ranges);
+}
+
+typedef void (*range_action_t)(struct memranges *ranges,
+                               resource_t begin, resource_t end,
+                               unsigned long tag);
+
+static void do_action(struct memranges *ranges,
+                      resource_t base, resource_t size, unsigned long tag,
+                      range_action_t action)
+{
+	resource_t end;
+	resource_t begin;
+
+	/* The addresses are aligned to 4096 bytes: the begin address is
+	 * aligned down while the end address is aligned up to be conservative
+	 * about the full range covered. */
+	begin = ALIGN_DOWN(base, 4096);
+	end = begin + size + (base - begin);
+	end = ALIGN_UP(end, 4096) - 1;
+	action(ranges, begin, end, tag);
+}
+
+void memranges_create_hole(struct memranges *ranges,
+                              resource_t base, resource_t size)
+{
+	do_action(ranges, base, size, -1, remove_memranges);
+}
+
+void memranges_insert(struct memranges *ranges,
+                      resource_t base, resource_t size, unsigned long tag)
+{
+	do_action(ranges, base, size, tag, merge_add_memranges);
+}
+
+struct collect_context {
+	struct memranges *ranges;
+	unsigned long tag;
+};
+
+static void collect_ranges(void *gp, struct device *dev, struct resource *res)
+{
+	struct collect_context *ctx = gp;
+
+	memranges_insert(ctx->ranges, res->base, res->size, ctx->tag);
+}
+
+void memranges_add_resources(struct memranges *ranges,
+                                 unsigned long mask, unsigned long match,
+                                 unsigned long tag)
+{
+	struct collect_context context;
+
+	/* Only deal with MEM resources. */
+	mask |= IORESOURCE_MEM;
+	match |= IORESOURCE_MEM;
+
+	context.ranges = ranges;
+	context.tag = tag;
+	search_global_resources(mask, match, collect_ranges, &context);
+}
+
+void memranges_init(struct memranges *ranges,
+                    unsigned long mask, unsigned long match,
+                    unsigned long tag)
+{
+	ranges->entries = NULL;
+	memranges_add_resources(ranges, mask, match, tag);
+}
+
+void memranges_teardown(struct memranges *ranges)
+{
+	while (ranges->entries != NULL) {
+		range_entry_unlink_and_free(&ranges->entries, ranges->entries);
+	}
+}
+
+void memranges_fill_holes_up_to(struct memranges *ranges,
+                                resource_t limit, unsigned long tag)
+{
+	struct range_entry *cur;
+	struct range_entry *prev;
+
+	prev = NULL;
+	for (cur = ranges->entries; cur != NULL; cur = cur->next) {
+		/* First entry. Just set prev. */
+		if (prev == NULL) {
+			prev = cur;
+			continue;
+		}
+
+		/* If the previous entry does not directly preceed the current
+		 * entry then add a new entry just after the previous one. */
+		if (range_entry_end(prev) != cur->begin) {
+			resource_t end;
+
+			end = cur->begin - 1;
+			if (end >= limit)
+				end = limit - 1;
+			range_list_add(&prev->next, range_entry_end(prev),
+			               end, tag);
+		}
+
+		prev = cur;
+
+		/* Hit the requested range limit. No other entries after this
+		 * are affected. */
+		if (cur->begin >= limit)
+			break;
+	}
+
+	/* Handle the case where the limit was never reached. A new entry needs
+	 * to be added to cover the range up to the limit. */
+	if (prev != NULL && range_entry_end(prev) < limit)
+		range_list_add(&prev->next, range_entry_end(prev),
+		               limit - 1, tag);
+
+	/* Merge all entries that were newly added. */
+	merge_neighbor_entries(ranges);
+}