cbmem: switch over to imd-based cbmem

By design, the imd library still provdes dynamic growth so that
feature is consistent.  The imd-based cbmem packs small allocations
into a larger entry using a tiered imd. The following examples show
the reduced fragmentation and reduced memory usage.

Before with dynamic cbmem:
CBMEM ROOT  0. 023ff000 00001000
aaaabbbb    1. 023fe000 00001000
aaaabbbc    2. 023fd000 00001000
aaaabbbe    3. 023fc000 00001000
aaaacccc    4. 023fa000 00002000
aaaacccd    5. 023f9000 00001000
ROMSTAGE    6. 023f8000 00001000
CONSOLE     7. 023d8000 00020000
COREBOOT    8. 023d6000 00002000

After with tiered imd:
IMD ROOT    0. 023ff000 00001000
IMD SMALL   1. 023fe000 00001000
aaaacccc    2. 023fc000 00001060
aaaacccd    3. 023fb000 000007cf
CONSOLE     4. 023db000 00020000
COREBOOT    5. 023d9000 00002000
IMD small region:
  IMD ROOT    0. 023fec00 00000400
  aaaabbbb    1. 023febe0 00000020
  aaaabbbc    2. 023feba0 00000040
  aaaabbbe    3. 023feb20 00000080
  ROMSTAGE    4. 023feb00 00000004

Side note: this CL provides a basis for what hoops one needs to
jump through when there are not writeable global variables on
a particular platform in the early stages.

Change-Id: If770246caa64b274819e45a26e100b62b9f8d2db
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9169
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

4 files changed, 317 insertions, 500 deletions

diff --git a/src/lib/Makefile.inc b/src/lib/Makefile.inc
index 043238a263..f0fb028741 100644
--- a/src/lib/Makefile.inc
+++ b/src/lib/Makefile.inc
@@ -99,8 +99,11 @@ ramstage-$(CONFIG_GENERIC_GPIO_LIB) += gpio.c
 ramstage-$(CONFIG_GENERIC_UDELAY) += timer.c
 ramstage-y += b64_decode.c
 
-romstage-y += cbmem_common.c dynamic_cbmem.c
-ramstage-y += cbmem_common.c dynamic_cbmem.c
+romstage-y += cbmem_common.c
+romstage-y += imd_cbmem.c
+
+ramstage-y += cbmem_common.c
+ramstage-y += imd_cbmem.c
 
 romstage-y += imd.c
 ramstage-y += imd.c
diff --git a/src/lib/cbmem_common.c b/src/lib/cbmem_common.c
index c3e838388d..6d581c40b2 100644
--- a/src/lib/cbmem_common.c
+++ b/src/lib/cbmem_common.c
@@ -18,39 +18,16 @@
  */
 #include <console/console.h>
 #include <cbmem.h>
-#include <stdlib.h>
+#include <bootstate.h>
+#include <rules.h>
+#if IS_ENABLED(CONFIG_ARCH_X86) && !IS_ENABLED(CONFIG_EARLY_CBMEM_INIT)
+#include <arch/acpi.h>
+#endif
 
 /* FIXME: Remove after CBMEM_INIT_HOOKS. */
 #include <console/cbmem_console.h>
 #include <timestamp.h>
 
-#ifndef __PRE_RAM__
-
-static const struct cbmem_id_to_name cbmem_ids[] = { CBMEM_ID_TO_NAME_TABLE };
-
-void cbmem_print_entry(int n, u32 id, u64 base, u64 size)
-{
-	int i;
-	const char *name;
-
-	name = NULL;
-	for (i = 0; i < ARRAY_SIZE(cbmem_ids); i++) {
-		if (cbmem_ids[i].id == id) {
-			name = cbmem_ids[i].name;
-			break;
-		}
-	}
-
-	if (name == NULL)
-		printk(BIOS_DEBUG, "%08x ", id);
-	else
-		printk(BIOS_DEBUG, "%s", name);
-	printk(BIOS_DEBUG, "%2d. ", n);
-	printk(BIOS_DEBUG, "%08llx ", base);
-	printk(BIOS_DEBUG, "%08llx\n", size);
-}
-
-#endif /* !__PRE_RAM__ */
 
 /* FIXME: Replace with CBMEM_INIT_HOOKS API. */
 #if !IS_ENABLED(CONFIG_ARCH_X86)
@@ -67,3 +44,16 @@ void __attribute__((weak)) cbmem_fail_resume(void)
 {
 }
 #endif
+
+#if ENV_RAMSTAGE && !IS_ENABLED(CONFIG_EARLY_CBMEM_INIT)
+static void init_cbmem_post_device(void *unused)
+{
+	if (acpi_is_wakeup())
+		cbmem_initialize();
+	else
+		cbmem_initialize_empty();
+}
+
+BOOT_STATE_INIT_ENTRY(BS_POST_DEVICE, BS_ON_ENTRY,
+			init_cbmem_post_device, NULL);
+#endif
diff --git a/src/lib/dynamic_cbmem.c b/src/lib/dynamic_cbmem.c
deleted file mode 100644
index c63cb46eb2..0000000000
--- a/src/lib/dynamic_cbmem.c
+++ /dev/null
@@ -1,470 +0,0 @@
-/*
- * 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 <bootstate.h>
-#include <bootmem.h>
-#include <console/console.h>
-#include <cbmem.h>
-#include <string.h>
-#include <stdlib.h>
-#include <arch/early_variables.h>
-#if IS_ENABLED(CONFIG_ARCH_X86) && !IS_ENABLED(CONFIG_EARLY_CBMEM_INIT)
-#include <arch/acpi.h>
-#endif
-#ifndef UINT_MAX
-#define UINT_MAX 4294967295U
-#endif
-
-/*
- * The dynamic cbmem code uses a root region. The root region boundary
- * addresses are determined by cbmem_top() and ROOT_MIN_SIZE. Just below
- * the address returned by cbmem_top() is a pointer that points to the
- * root data structure. The root data structure provides the book keeping
- * for each large entry.
- */
-
-/* The root region is at least DYN_CBMEM_ALIGN_SIZE . */
-#define ROOT_MIN_SIZE DYN_CBMEM_ALIGN_SIZE
-#define CBMEM_POINTER_MAGIC 0xc0389479
-#define CBMEM_ENTRY_MAGIC ~(CBMEM_POINTER_MAGIC)
-
-/* The cbmem_root_pointer structure lives just below address returned
- * from cbmem_top(). It points to the root data structure that
- * maintains the entries. */
-struct cbmem_root_pointer {
-	u32 magic;
-	u32 root;
-} __attribute__((packed));
-
-struct cbmem_entry {
-	u32 magic;
-	u32 start;
-	u32 size;
-	u32 id;
-} __attribute__((packed));
-
-struct cbmem_root {
-	u32 max_entries;
-	u32 num_entries;
-	u32 locked;
-	u32 size;
-	struct cbmem_entry entries[0];
-} __attribute__((packed));
-
-
-#if !defined(__PRE_RAM__)
-static void *cached_cbmem_top;
-
-void cbmem_set_top(void * ramtop)
-{
-	cached_cbmem_top = ramtop;
-}
-#endif
-
-static inline void *cbmem_top_cached(void)
-{
-#if !defined(__PRE_RAM__)
-	if (cached_cbmem_top == NULL)
-		cached_cbmem_top = cbmem_top();
-
-	return cached_cbmem_top;
-#else
-	return cbmem_top();
-#endif
-}
-
-static inline uintptr_t get_top_aligned(void)
-{
-	uintptr_t top;
-
-	/* Align down what is returned from cbmem_top(). */
-	top = (uintptr_t)cbmem_top_cached();
-	top &= ~(DYN_CBMEM_ALIGN_SIZE - 1);
-
-	return top;
-}
-
-static inline void *get_root(void)
-{
-	uintptr_t pointer_addr;
-	struct cbmem_root_pointer *pointer;
-
-	pointer_addr = get_top_aligned();
-	if (pointer_addr == 0)
-		return NULL;
-
-	pointer_addr -= sizeof(struct cbmem_root_pointer);
-
-	pointer = (void *)pointer_addr;
-	if (pointer->magic != CBMEM_POINTER_MAGIC)
-		return NULL;
-
-	pointer_addr = pointer->root;
-	return (void *)pointer_addr;
-}
-
-static inline void cbmem_entry_assign(struct cbmem_entry *entry,
-                                      u32 id, u32 start, u32 size)
-{
-	entry->magic = CBMEM_ENTRY_MAGIC;
-	entry->start = start;
-	entry->size = size;
-	entry->id = id;
-}
-
-static inline const struct cbmem_entry *
-cbmem_entry_append(struct cbmem_root *root, u32 id, u32 start, u32 size)
-{
-	struct cbmem_entry *cbmem_entry;
-
-	cbmem_entry = &root->entries[root->num_entries];
-	root->num_entries++;
-
-	cbmem_entry_assign(cbmem_entry, id, start, size);
-
-	return cbmem_entry;
-}
-
-void cbmem_initialize_empty(void)
-{
-	uintptr_t pointer_addr;
-	uintptr_t root_addr;
-	unsigned long max_entries;
-	struct cbmem_root *root;
-	struct cbmem_root_pointer *pointer;
-
-	/* Place the root pointer and the root. The number of entries is
-	 * dictated by difference between the root address and the pointer
-	 * where the root address is aligned down to
-	 * DYN_CBMEM_ALIGN_SIZE. The pointer falls just below the
-	 * address returned by get_top_aligned(). */
-	pointer_addr = get_top_aligned();
-	if (pointer_addr == 0)
-		return;
-
-	root_addr = pointer_addr - ROOT_MIN_SIZE;
-	root_addr &= ~(DYN_CBMEM_ALIGN_SIZE - 1);
-	pointer_addr -= sizeof(struct cbmem_root_pointer);
-
-	max_entries = (pointer_addr - (root_addr + sizeof(*root))) /
-	              sizeof(struct cbmem_entry);
-
-	pointer = (void *)pointer_addr;
-	pointer->magic = CBMEM_POINTER_MAGIC;
-	pointer->root = root_addr;
-
-	root = (void *)root_addr;
-	root->max_entries = max_entries;
-	root->num_entries = 0;
-	root->locked = 0;
-	root->size = pointer_addr - root_addr +
-	             sizeof(struct cbmem_root_pointer);
-
-	/* Add an entry covering the root region. */
-	cbmem_entry_append(root, CBMEM_ID_ROOT, root_addr, root->size);
-
-	printk(BIOS_DEBUG, "CBMEM: root @ %p %d entries.\n",
-	       root, root->max_entries);
-
-	/* Complete migration to CBMEM. */
-	cbmem_run_init_hooks();
-}
-
-static inline int cbmem_fail_recovery(void)
-{
-	cbmem_initialize_empty();
-	cbmem_fail_resume();
-	return 1;
-}
-
-static int validate_entries(struct cbmem_root *root)
-{
-	unsigned int i;
-	uintptr_t current_end;
-
-	current_end = get_top_aligned();
-
-	printk(BIOS_DEBUG, "CBMEM: recovering %d/%d entries from root @ %p\n",
-	       root->num_entries, root->max_entries, root);
-
-	/* Check that all regions are properly aligned and are just below
-	 * the previous entry */
-	for (i = 0; i < root->num_entries; i++) {
-		struct cbmem_entry *entry = &root->entries[i];
-
-		if (entry->magic != CBMEM_ENTRY_MAGIC)
-			return -1;
-
-		if (entry->start & (DYN_CBMEM_ALIGN_SIZE - 1))
-			return -1;
-
-		if (entry->start + entry->size != current_end)
-			return -1;
-
-		current_end = entry->start;
-	}
-
-	return 0;
-}
-
-int cbmem_initialize(void)
-{
-	struct cbmem_root *root;
-	uintptr_t top_according_to_root;
-
-	root = get_root();
-
-	/* No recovery possible since root couldn't be recovered. */
-	if (root == NULL)
-		return cbmem_fail_recovery();
-
-	/* Sanity check the root. */
-	top_according_to_root = (root->size + (uintptr_t)root);
-	if (get_top_aligned() != top_according_to_root)
-		return cbmem_fail_recovery();
-
-	if (root->num_entries > root->max_entries)
-		return cbmem_fail_recovery();
-
-	if ((root->max_entries * sizeof(struct cbmem_entry)) >
-	    (root->size - sizeof(struct cbmem_root_pointer) - sizeof(*root)))
-		return cbmem_fail_recovery();
-
-	/* Validate current entries. */
-	if (validate_entries(root))
-		return cbmem_fail_recovery();
-
-#if defined(__PRE_RAM__)
-	/* Lock the root in the romstage on a recovery. The assumption is that
-	 * recovery is called during romstage on the S3 resume path. */
-	root->locked = 1;
-#endif
-
-	/* Complete migration to CBMEM. */
-	cbmem_run_init_hooks();
-
-	/* Recovery successful. */
-	return 0;
-}
-
-int cbmem_recovery(int is_wakeup)
-{
-	int rv = 0;
-	if (!is_wakeup)
-		cbmem_initialize_empty();
-	else
-		rv = cbmem_initialize();
-	return rv;
-}
-
-static uintptr_t cbmem_base(void)
-{
-	struct cbmem_root *root;
-	uintptr_t low_addr;
-
-	root = get_root();
-
-	if (root == NULL)
-		return 0;
-
-	low_addr = (uintptr_t)root;
-	/* a low address is low. */
-	low_addr &= 0xffffffff;
-
-	/* Assume the lowest address is the last one added. */
-	if (root->num_entries > 0) {
-		low_addr = root->entries[root->num_entries - 1].start;
-	}
-
-	return low_addr;
-}
-
-
-const struct cbmem_entry *cbmem_entry_add(u32 id, u64 size64)
-{
-	struct cbmem_root *root;
-	const struct cbmem_entry *entry;
-	uintptr_t base;
-	u32 size;
-	u32 aligned_size;
-
-	entry = cbmem_entry_find(id);
-
-	if (entry != NULL)
-		return entry;
-
-	/* Only handle sizes <= UINT_MAX internally. */
-	if (size64 > (u64)UINT_MAX)
-		return NULL;
-
-	size = size64;
-
-	root = get_root();
-
-	if (root == NULL)
-		return NULL;
-
-	/* Nothing can be added once it is locked down. */
-	if (root->locked)
-		return NULL;
-
-	if (root->max_entries == root->num_entries)
-		return NULL;
-
-	aligned_size = ALIGN(size, DYN_CBMEM_ALIGN_SIZE);
-	base = cbmem_base();
-	base -= aligned_size;
-
-	return cbmem_entry_append(root, id, base, aligned_size);
-}
-
-void *cbmem_add(u32 id, u64 size)
-{
-	const struct cbmem_entry *entry;
-
-	entry = cbmem_entry_add(id, size);
-
-	if (entry == NULL)
-		return NULL;
-
-	return cbmem_entry_start(entry);
-}
-
-/* Retrieve a region provided a given id. */
-const struct cbmem_entry *cbmem_entry_find(u32 id)
-{
-	struct cbmem_root *root;
-	const struct cbmem_entry *entry;
-	unsigned int i;
-
-	root = get_root();
-
-	if (root == NULL)
-		return NULL;
-
-	entry = NULL;
-
-	for (i = 0; i < root->num_entries; i++) {
-		if (root->entries[i].id == id) {
-			entry = &root->entries[i];
-			break;
-		}
-	}
-
-	return entry;
-}
-
-void *cbmem_find(u32 id)
-{
-	const struct cbmem_entry *entry;
-
-	entry = cbmem_entry_find(id);
-
-	if (entry == NULL)
-		return NULL;
-
-	return cbmem_entry_start(entry);
-}
-
-/* Remove a reserved region. Returns 0 on success, < 0 on error. Note: A region
- * cannot be removed unless it was the last one added. */
-int cbmem_entry_remove(const struct cbmem_entry *entry)
-{
-	unsigned long entry_num;
-	struct cbmem_root *root;
-
-	root = get_root();
-
-	if (root == NULL)
-		return -1;
-
-	if (root->num_entries == 0)
-		return -1;
-
-	/* Nothing can be removed. */
-	if (root->locked)
-		return -1;
-
-	entry_num = entry - &root->entries[0];
-
-	/* If the entry is the last one in the root it can be removed. */
-	if (entry_num == (root->num_entries - 1)) {
-		root->num_entries--;
-		return 0;
-	}
-
-	return -1;
-}
-
-u64 cbmem_entry_size(const struct cbmem_entry *entry)
-{
-	return entry->size;
-}
-
-void *cbmem_entry_start(const struct cbmem_entry *entry)
-{
-	uintptr_t addr = entry->start;
-	return (void *)addr;
-}
-
-
-#if !defined(__PRE_RAM__)
-
-#if !IS_ENABLED(CONFIG_EARLY_CBMEM_INIT)
-static void init_cbmem_post_device(void *unused)
-{
-	if (acpi_is_wakeup())
-		cbmem_initialize();
-	else
-		cbmem_initialize_empty();
-}
-
-BOOT_STATE_INIT_ENTRY(BS_POST_DEVICE, BS_ON_ENTRY,
-			init_cbmem_post_device, NULL);
-#endif
-
-void cbmem_add_bootmem(void)
-{
-	uintptr_t base;
-	uintptr_t top;
-
-	base = cbmem_base();
-	top = get_top_aligned();
-	bootmem_add_range(base, top - base, LB_MEM_TABLE);
-}
-
-void cbmem_list(void)
-{
-	unsigned int i;
-	struct cbmem_root *root;
-
-	root = get_root();
-
-	if (root == NULL)
-		return;
-
-	for (i = 0; i < root->num_entries; i++) {
-		struct cbmem_entry *entry;
-
-		entry = &root->entries[i];
-
-		cbmem_print_entry(i, entry->id, entry->start, entry->size);
-	}
-}
-#endif /* __PRE_RAM__ */
diff --git a/src/lib/imd_cbmem.c b/src/lib/imd_cbmem.c
new file mode 100644
index 0000000000..0649bf3b17
--- /dev/null
+++ b/src/lib/imd_cbmem.c
@@ -0,0 +1,294 @@
+/*
+ * 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.
+ */
+
+#include <bootstate.h>
+#include <bootmem.h>
+#include <console/console.h>
+#include <cbmem.h>
+#include <imd.h>
+#include <rules.h>
+#include <string.h>
+#include <stdlib.h>
+#include <arch/early_variables.h>
+#if IS_ENABLED(CONFIG_ARCH_X86) && !IS_ENABLED(CONFIG_EARLY_CBMEM_INIT)
+#include <arch/acpi.h>
+#endif
+
+/* The root region is at least DYN_CBMEM_ALIGN_SIZE . */
+#define ROOT_MIN_SIZE DYN_CBMEM_ALIGN_SIZE
+#define LG_ALIGN ROOT_MIN_SIZE
+/* Small allocation parameters. */
+#define SM_ROOT_SIZE 1024
+#define SM_ALIGN 32
+
+static inline struct imd *cbmem_get_imd(void)
+{
+	/* Only supply a backing store for imd in ramstage. */
+	if (ENV_RAMSTAGE) {
+		static struct imd imd_cbmem;
+		return &imd_cbmem;
+	}
+	return NULL;
+}
+
+/*
+ * x86 !CONFIG_EARLY_CBMEM_INIT platforms need to do the following in ramstage:
+ * 1. Call set_top_of_ram() which in turn calls cbmem_set_top().
+ * 2. Provide a get_top_of_ram() implementation.
+ *
+ * CONFIG_EARLY_CBMEM_INIT platforms just need to provide cbmem_top().
+ */
+void cbmem_set_top(void *ramtop)
+{
+	struct imd *imd = cbmem_get_imd();
+
+	imd_handle_init(imd, ramtop);
+}
+
+static inline const struct cbmem_entry *imd_to_cbmem(const struct imd_entry *e)
+{
+	return (const struct cbmem_entry *)e;
+}
+
+static inline const struct imd_entry *cbmem_to_imd(const struct cbmem_entry *e)
+{
+	return (const struct imd_entry *)e;
+}
+
+/* These are the different situations to handle:
+ *  CONFIG_EARLY_CBMEM_INIT:
+ *  	In ramstage cbmem_initialize() attempts a recovery of the
+ *  	cbmem region set up by romstage. It uses cbmem_top() as the
+ *  	starting point of recovery.
+ *
+ *  	In romstage, similar to ramstage,  cbmem_initialize() needs to
+ *  	attempt recovery of the cbmem area using cbmem_top() as the limit.
+ *  	cbmem_initialize_empty() initializes an empty cbmem area from
+ *  	cbmem_top();
+ *
+ */
+static struct imd *imd_init_backing(struct imd *backing)
+{
+	struct imd *imd;
+
+	imd = cbmem_get_imd();
+
+	if (imd != NULL)
+		return imd;
+
+	imd = backing;
+
+	return imd;
+}
+
+static struct imd *imd_init_backing_with_recover(struct imd *backing)
+{
+	struct imd *imd;
+
+	imd = imd_init_backing(backing);
+	if (!ENV_RAMSTAGE) {
+		/* Early cbmem init platforms need to always use cbmem_top(). */
+		if (IS_ENABLED(CONFIG_EARLY_CBMEM_INIT))
+			imd_handle_init(imd, cbmem_top());
+		/* Need to partially recover all the time outside of ramstage
+		 * because there's object storage outside of the stack. */
+		imd_handle_init_partial_recovery(imd);
+	}
+
+	return imd;
+}
+
+void cbmem_initialize_empty(void)
+{
+	struct imd *imd;
+	struct imd imd_backing;
+
+	imd = imd_init_backing(&imd_backing);
+
+	/* Early cbmem init platforms need to always use cbmem_top(). */
+	if (IS_ENABLED(CONFIG_EARLY_CBMEM_INIT))
+		imd_handle_init(imd, cbmem_top());
+
+	printk(BIOS_DEBUG, "CBMEM:\n");
+
+	if (imd_create_tiered_empty(imd, ROOT_MIN_SIZE, LG_ALIGN,
+					SM_ROOT_SIZE, SM_ALIGN)) {
+		printk(BIOS_DEBUG, "failed.\n");
+		return;
+	}
+
+	/* Complete migration to CBMEM. */
+	cbmem_run_init_hooks();
+}
+
+static inline int cbmem_fail_recovery(void)
+{
+	cbmem_initialize_empty();
+	cbmem_fail_resume();
+	return 1;
+}
+
+int cbmem_initialize(void)
+{
+	struct imd *imd;
+	struct imd imd_backing;
+
+	imd = imd_init_backing(&imd_backing);
+
+	/* Early cbmem init platforms need to always use cbmem_top(). */
+	if (IS_ENABLED(CONFIG_EARLY_CBMEM_INIT))
+		imd_handle_init(imd, cbmem_top());
+
+	if (imd_recover(imd))
+		return 1;
+
+#if defined(__PRE_RAM__)
+	/*
+	 * Lock the imd in romstage on a recovery. The assumption is that
+	 * if the imd area was recovered in romstage then S3 resume path
+	 * is being taken.
+	 */
+	imd_lockdown(imd);
+#endif
+
+	/* Complete migration to CBMEM. */
+	cbmem_run_init_hooks();
+
+	/* Recovery successful. */
+	return 0;
+}
+
+int cbmem_recovery(int is_wakeup)
+{
+	int rv = 0;
+	if (!is_wakeup)
+		cbmem_initialize_empty();
+	else
+		rv = cbmem_initialize();
+	return rv;
+}
+
+const struct cbmem_entry *cbmem_entry_add(u32 id, u64 size64)
+{
+	struct imd *imd;
+	struct imd imd_backing;
+	const struct imd_entry *e;
+
+	imd = imd_init_backing_with_recover(&imd_backing);
+
+	e = imd_entry_find_or_add(imd, id, size64);
+
+	return imd_to_cbmem(e);
+}
+
+void *cbmem_add(u32 id, u64 size)
+{
+	struct imd *imd;
+	struct imd imd_backing;
+	const struct imd_entry *e;
+
+	imd = imd_init_backing_with_recover(&imd_backing);
+
+	e = imd_entry_find_or_add(imd, id, size);
+
+	if (e == NULL)
+		return NULL;
+
+	return imd_entry_at(imd, e);
+}
+
+/* Retrieve a region provided a given id. */
+const struct cbmem_entry *cbmem_entry_find(u32 id)
+{
+	struct imd *imd;
+	struct imd imd_backing;
+	const struct imd_entry *e;
+
+	imd = imd_init_backing_with_recover(&imd_backing);
+
+	e = imd_entry_find(imd, id);
+
+	return imd_to_cbmem(e);
+}
+
+void *cbmem_find(u32 id)
+{
+	struct imd *imd;
+	struct imd imd_backing;
+	const struct imd_entry *e;
+
+	imd = imd_init_backing_with_recover(&imd_backing);
+
+	e = imd_entry_find(imd, id);
+
+	if (e == NULL)
+		return NULL;
+
+	return imd_entry_at(imd, e);
+}
+
+/* Remove a reserved region. Returns 0 on success, < 0 on error. Note: A region
+ * cannot be removed unless it was the last one added. */
+int cbmem_entry_remove(const struct cbmem_entry *entry)
+{
+	struct imd *imd;
+	struct imd imd_backing;
+
+	imd = imd_init_backing_with_recover(&imd_backing);
+
+	return imd_entry_remove(imd, cbmem_to_imd(entry));
+}
+
+u64 cbmem_entry_size(const struct cbmem_entry *entry)
+{
+	struct imd *imd;
+	struct imd imd_backing;
+
+	imd = imd_init_backing_with_recover(&imd_backing);
+
+	return imd_entry_size(imd, cbmem_to_imd(entry));
+}
+
+void *cbmem_entry_start(const struct cbmem_entry *entry)
+{
+	struct imd *imd;
+	struct imd imd_backing;
+
+	imd = imd_init_backing_with_recover(&imd_backing);
+
+	return imd_entry_at(imd, cbmem_to_imd(entry));
+}
+
+#if ENV_RAMSTAGE
+void cbmem_add_bootmem(void)
+{
+	void *base = NULL;
+	size_t size = 0;
+
+	imd_region_used(cbmem_get_imd(), &base, &size);
+	bootmem_add_range((uintptr_t)base, size, LB_MEM_TABLE);
+}
+
+void cbmem_list(void)
+{
+	static const struct imd_lookup lookup[] = { CBMEM_ID_TO_NAME_TABLE };
+
+	imd_print_entries(cbmem_get_imd(), lookup, ARRAY_SIZE(lookup));
+}
+#endif /* __PRE_RAM__ */