cbmem: dynamic cbmem support

This patch adds a parallel implementation of cbmem that supports
dynamic sizing. The original implementation relied on reserving
a fixed-size block of memory for adding cbmem entries. In order to
allow for more flexibility for adding cbmem allocations the dynamic
cbmem infrastructure was developed as an alternative to the fixed block
approach. Also, the amount of memory to reserve for cbmem allocations
does not need to be known prior to the first allocation.

The dynamic cbmem code implements the same API as the existing cbmem
code except for cbmem_init() and cbmem_reinit(). The add and find
routines behave the same way. The dynamic cbmem infrastructure
uses a top down allocator that starts allocating from a board/chipset
defined function cbmem_top(). A root pointer lives just below
cbmem_top(). In turn that pointer points to the root block which
contains the entries for all the large alloctations. The corresponding
block for each large allocation falls just below the previous entry.

It should be noted that this implementation rounds all allocations
up to a 4096 byte granularity. Though a packing allocator could
be written for small allocations it was deemed OK to just fragment
the memory as there shouldn't be that many small allocations. The
result is less code with a tradeoff of some wasted memory.

           +----------------------+ <- cbmem_top()
  |   +----|   root pointer       |
  |   |    +----------------------+
  |   |    |                      |--------+
  |   +--->|   root block         |-----+  |
  |        +----------------------+     |  |
  |        |                      |     |  |
  |        |                      |     |  |
  |        |   alloc N            |<----+  |
  |        +----------------------+        |
  |        |                      |        |
  |        |                      |        |
 \|/       |   alloc N + 1        |<-------+
  v        +----------------------+

In addition to preserving the previous cbmem API, the dynamic
cbmem API allows for removing blocks from cbmem. This allows for
the boot process to allocate memory that can be discarded after
it's been used for performing more complex boot tasks in romstage.

In order to plumb this support in there were some issues to work
around regarding writing of coreboot tables. There were a few
assumptions to how cbmem was layed out which dictated some ifdef
guarding and other runtime checks so as not to incorrectly
tag the e820 and coreboot memory tables.

The example shown below is using dynamic cbmem infrastructure.
The reserved memory for cbmem is less than 512KiB.

coreboot memory table:
 0. 0000000000000000-0000000000000fff: CONFIGURATION TABLES
 1. 0000000000001000-000000000002ffff: RAM
 2. 0000000000030000-000000000003ffff: RESERVED
 3. 0000000000040000-000000000009ffff: RAM
 4. 00000000000a0000-00000000000fffff: RESERVED
 5. 0000000000100000-0000000000efffff: RAM
 6. 0000000000f00000-0000000000ffffff: RESERVED
 7. 0000000001000000-000000007bf80fff: RAM
 8. 000000007bf81000-000000007bffffff: CONFIGURATION TABLES
 9. 000000007c000000-000000007e9fffff: RESERVED
10. 00000000f0000000-00000000f3ffffff: RESERVED
11. 00000000fed10000-00000000fed19fff: RESERVED
12. 00000000fed84000-00000000fed84fff: RESERVED
13. 0000000100000000-00000001005fffff: RAM
Wrote coreboot table at: 7bf81000, 0x39c bytes, checksum f5bf
coreboot table: 948 bytes.
CBMEM ROOT  0. 7bfff000 00001000
MRC DATA    1. 7bffe000 00001000
ROMSTAGE    2. 7bffd000 00001000
TIME STAMP  3. 7bffc000 00001000
ROMSTG STCK 4. 7bff7000 00005000
CONSOLE     5. 7bfe7000 00010000
VBOOT       6. 7bfe6000 00001000
RAMSTAGE    7. 7bf98000 0004e000
GDT         8. 7bf97000 00001000
ACPI        9. 7bf8b000 0000c000
ACPI GNVS  10. 7bf8a000 00001000
SMBIOS     11. 7bf89000 00001000
COREBOOT   12. 7bf81000 00008000

And the corresponding e820 entries:
BIOS-e820: [mem 0x0000000000000000-0x0000000000000fff] type 16
BIOS-e820: [mem 0x0000000000001000-0x000000000002ffff] usable
BIOS-e820: [mem 0x0000000000030000-0x000000000003ffff] reserved
BIOS-e820: [mem 0x0000000000040000-0x000000000009ffff] usable
BIOS-e820: [mem 0x00000000000a0000-0x00000000000fffff] reserved
BIOS-e820: [mem 0x0000000000100000-0x0000000000efffff] usable
BIOS-e820: [mem 0x0000000000f00000-0x0000000000ffffff] reserved
BIOS-e820: [mem 0x0000000001000000-0x000000007bf80fff] usable
BIOS-e820: [mem 0x000000007bf81000-0x000000007bffffff] type 16
BIOS-e820: [mem 0x000000007c000000-0x000000007e9fffff] reserved
BIOS-e820: [mem 0x00000000f0000000-0x00000000f3ffffff] reserved
BIOS-e820: [mem 0x00000000fed10000-0x00000000fed19fff] reserved
BIOS-e820: [mem 0x00000000fed84000-0x00000000fed84fff] reserved
BIOS-e820: [mem 0x0000000100000000-0x00000001005fffff] usable

Change-Id: Ie3bca52211800a8652a77ca684140cfc9b3b9a6b
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2848
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

5 files changed, 548 insertions, 28 deletions

diff --git a/src/lib/Makefile.inc b/src/lib/Makefile.inc
index 132e662d8c..1f2ad96735 100644
--- a/src/lib/Makefile.inc
+++ b/src/lib/Makefile.inc
@@ -42,7 +42,6 @@ romstage-y += cbfs.c
 romstage-y += lzma.c
 #romstage-y += lzmadecode.c
 romstage-$(CONFIG_CACHE_AS_RAM) += ramtest.c
-romstage-$(CONFIG_HAVE_ACPI_RESUME) += cbmem.c
 romstage-$(CONFIG_CONSOLE_SERIAL8250) += uart8250.c
 romstage-$(CONFIG_CONSOLE_SERIAL8250MEM) += uart8250mem.c
 romstage-$(CONFIG_CONSOLE_CBMEM) += cbmem_console.c
@@ -76,7 +75,6 @@ ramstage-y += lzma.c
 ramstage-y += stack.c
 ramstage-$(CONFIG_ARCH_X86) += gcc.c
 ramstage-y += clog2.c
-ramstage-y += cbmem.c
 ramstage-$(CONFIG_CONSOLE_SERIAL8250) += uart8250.c
 ramstage-$(CONFIG_CONSOLE_SERIAL8250MEM) += uart8250mem.c
 ramstage-$(CONFIG_CONSOLE_CBMEM) += cbmem_console.c
@@ -87,6 +85,16 @@ ramstage-$(CONFIG_COLLECT_TIMESTAMPS) += timestamp.c
 ramstage-$(CONFIG_COVERAGE) += libgcov.c
 ramstage-$(CONFIG_MAINBOARD_DO_NATIVE_VGA_INIT) += edid.c
 
+# The CBMEM implementations are chosen based on CONFIG_DYNAMIC_CBMEM.
+ifeq ($(CONFIG_DYNAMIC_CBMEM),y)
+ramstage-y += dynamic_cbmem.c
+romstage-y += dynamic_cbmem.c
+else
+ramstage-y += cbmem.c
+romstage-$(CONFIG_HAVE_ACPI_RESUME) += cbmem.c
+endif # CONFIG_DYNAMIC_CBMEM
+ramstage-y += cbmem_info.c
+
 ramstage-$(CONFIG_CONSOLE_NE2K) += ne2k.c
 
 ifneq ($(CONFIG_HAVE_ARCH_MEMSET),y)
diff --git a/src/lib/cbmem.c b/src/lib/cbmem.c
index 5663cc85c4..ad98082861 100644
--- a/src/lib/cbmem.c
+++ b/src/lib/cbmem.c
@@ -232,6 +232,18 @@ int cbmem_initialize(void)
 #endif
 
 #ifndef __PRE_RAM__
+/* cbmem cannot be initialized before device drivers, but it can be initialized
+ * after the drivers have run. */
+void init_cbmem_pre_device(void) {}
+
+void init_cbmem_post_device(void)
+{
+	cbmem_initialize();
+#if CONFIG_CONSOLE_CBMEM
+	cbmemc_reinit();
+#endif
+}
+
 void cbmem_list(void)
 {
 	struct cbmem_entry *cbmem_toc;
@@ -245,28 +257,8 @@ void cbmem_list(void)
 
 		if (cbmem_toc[i].magic != CBMEM_MAGIC)
 			continue;
-		printk(BIOS_DEBUG, "%2d. ", i);
-		switch (cbmem_toc[i].id) {
-		case CBMEM_ID_FREESPACE: printk(BIOS_DEBUG, "FREE SPACE "); break;
-		case CBMEM_ID_GDT:	 printk(BIOS_DEBUG, "GDT        "); break;
-		case CBMEM_ID_ACPI:	 printk(BIOS_DEBUG, "ACPI       "); break;
-		case CBMEM_ID_CBTABLE:	 printk(BIOS_DEBUG, "COREBOOT   "); break;
-		case CBMEM_ID_PIRQ:	 printk(BIOS_DEBUG, "IRQ TABLE  "); break;
-		case CBMEM_ID_MPTABLE:	 printk(BIOS_DEBUG, "SMP TABLE  "); break;
-		case CBMEM_ID_RESUME:	 printk(BIOS_DEBUG, "ACPI RESUME"); break;
-		case CBMEM_ID_RESUME_SCRATCH:	 printk(BIOS_DEBUG, "ACPISCRATCH"); break;
-		case CBMEM_ID_ACPI_GNVS: printk(BIOS_DEBUG, "ACPI GNVS  "); break;
-		case CBMEM_ID_SMBIOS:    printk(BIOS_DEBUG, "SMBIOS     "); break;
-		case CBMEM_ID_TIMESTAMP: printk(BIOS_DEBUG, "TIME STAMP "); break;
-		case CBMEM_ID_MRCDATA:	 printk(BIOS_DEBUG, "MRC DATA   "); break;
-		case CBMEM_ID_CONSOLE:   printk(BIOS_DEBUG, "CONSOLE    "); break;
-		case CBMEM_ID_ELOG:      printk(BIOS_DEBUG, "ELOG       "); break;
-		case CBMEM_ID_COVERAGE:  printk(BIOS_DEBUG, "COVERAGE   "); break;
-		case CBMEM_ID_ROMSTAGE_INFO:   printk(BIOS_DEBUG, "ROMSTAGE   "); break;
-		default: printk(BIOS_DEBUG, "%08x ", cbmem_toc[i].id);
-		}
-		printk(BIOS_DEBUG, "%08llx ", cbmem_toc[i].base);
-		printk(BIOS_DEBUG, "%08llx\n", cbmem_toc[i].size);
+		cbmem_print_entry(i, cbmem_toc[i].id, cbmem_toc[i].base,
+		                  cbmem_toc[i].size);
 	}
 }
 #endif
diff --git a/src/lib/cbmem_info.c b/src/lib/cbmem_info.c
new file mode 100644
index 0000000000..aaf5840684
--- /dev/null
+++ b/src/lib/cbmem_info.c
@@ -0,0 +1,69 @@
+/*
+ * 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 wacbmem_entryanty 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 <console/console.h>
+#include <cbmem.h>
+#include <stdlib.h>
+
+static struct cbmem_id_to_name {
+	u32 id;
+	const char *name;
+} cbmem_ids[] = {
+	{ CBMEM_ID_FREESPACE,		"FREE SPACE " },
+	{ CBMEM_ID_GDT,			"GDT        " },
+	{ CBMEM_ID_ACPI,		"ACPI       " },
+	{ CBMEM_ID_CBTABLE,		"COREBOOT   " },
+	{ CBMEM_ID_PIRQ,		"IRQ TABLE  " },
+	{ CBMEM_ID_MPTABLE,		"SMP TABLE  " },
+	{ CBMEM_ID_RESUME,		"ACPI RESUME" },
+	{ CBMEM_ID_RESUME_SCRATCH,	"ACPISCRATCH" },
+	{ CBMEM_ID_ACPI_GNVS,		"ACPI GNVS  " },
+	{ CBMEM_ID_SMBIOS,		"SMBIOS     " },
+	{ CBMEM_ID_TIMESTAMP,		"TIME STAMP " },
+	{ CBMEM_ID_MRCDATA,		"MRC DATA   " },
+	{ CBMEM_ID_CONSOLE,		"CONSOLE    " },
+	{ CBMEM_ID_ELOG,		"ELOG       " },
+	{ CBMEM_ID_COVERAGE,		"COVERAGE   " },
+	{ CBMEM_ID_ROMSTAGE_INFO,	"ROMSTAGE   " },
+	{ CBMEM_ID_ROMSTAGE_RAM_STACK,	"ROMSTG STCK" },
+	{ CBMEM_ID_RAMSTAGE,		"RAMSTAGE   " },
+	{ CBMEM_ID_RAMSTAGE_CACHE,	"RAMSTAGE $ " },
+	{ CBMEM_ID_ROOT,		"CBMEM ROOT " },
+};
+
+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);
+}
diff --git a/src/lib/dynamic_cbmem.c b/src/lib/dynamic_cbmem.c
new file mode 100644
index 0000000000..ae6c87ac87
--- /dev/null
+++ b/src/lib/dynamic_cbmem.c
@@ -0,0 +1,452 @@
+/*
+ * 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 wacbmem_entryanty 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 <boot/tables.h>
+#include <console/console.h>
+#include <cbmem.h>
+#include <string.h>
+#include <stdlib.h>
+#if CONFIG_HAVE_ACPI_RESUME && !defined(__PRE_RAM__)
+#include <arch/acpi.h>
+#endif
+
+#ifndef UINT_MAX
+#define UINT_MAX 4294967295U
+#endif
+
+/* ACPI resume needs to be cleared in the fail-to-recover case, but that
+ * condition is only handled during ramstage. */
+#if CONFIG_HAVE_ACPI_RESUME && !defined(__PRE_RAM__)
+static inline void cbmem_handle_acpi_resume(void)
+{
+	/* Something went wrong, our high memory area got wiped */
+	if (acpi_slp_type == 3 || acpi_slp_type == 2)
+		acpi_slp_type = 0;
+}
+#else
+static inline void cbmem_handle_acpi_resume(void) {}
+#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));
+
+
+static inline void *cbmem_top_cached(void)
+{
+#if !defined(__PRE_RAM__)
+	static void *cached_cbmem_top;
+
+	if (cached_cbmem_top == NULL)
+		cached_cbmem_top = cbmem_top();
+
+	return cached_cbmem_top;
+#else
+	return cbmem_top();
+#endif
+}
+
+static inline void *get_top_aligned(void)
+{
+	unsigned long top;
+
+	/* Align down what is returned from cbmem_top(). */
+	top = (unsigned long)cbmem_top_cached();
+	top &= ~(DYN_CBMEM_ALIGN_SIZE - 1);
+
+	return (void *)top;
+}
+
+static inline void *get_root(void)
+{
+	unsigned long pointer_addr;
+	struct cbmem_root_pointer *pointer;
+
+	pointer_addr = (unsigned long)get_top_aligned();
+	pointer_addr -= sizeof(struct cbmem_root_pointer);
+
+	pointer = (void *)pointer_addr;
+	if (pointer->magic != CBMEM_POINTER_MAGIC)
+		return NULL;
+
+	return (void *)pointer->root;
+}
+
+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)
+{
+	unsigned long pointer_addr;
+	unsigned long 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 = (unsigned long)get_top_aligned();
+	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);
+
+	cbmem_arch_init();
+}
+
+static inline int cbmem_fail_recovery(void)
+{
+	cbmem_initialize_empty();
+	cbmem_handle_acpi_resume();
+	return 1;
+}
+
+static int validate_entries(struct cbmem_root *root)
+{
+	unsigned int i;
+	u32 current_end;
+
+	current_end = (u32)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;
+	void *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 = (void *)(root->size + (unsigned long)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
+
+	cbmem_arch_init();
+
+	/* Recovery successful. */
+	return 0;
+}
+
+static void *cbmem_base(void)
+{
+	struct cbmem_root *root;
+	u32 low_addr;
+
+	root = get_root();
+
+	if (root == NULL)
+		return NULL;
+
+	low_addr = (u32)root;
+
+	/* Assume the lowest address is the last one added. */
+	if (root->num_entries > 0) {
+		low_addr = root->entries[root->num_entries - 1].start;
+	}
+
+	return (void *)low_addr;
+}
+
+
+const struct cbmem_entry *cbmem_entry_add(u32 id, u64 size64)
+{
+	struct cbmem_root *root;
+	const struct cbmem_entry *entry;
+	unsigned long 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 = (unsigned long)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)
+{
+	return (void *)entry->start;
+}
+
+
+#if !defined(__PRE_RAM__)
+/* selected cbmem can be initialized early in ramstage. Additionally, that
+ * means cbmem console can be reinitialized early as well. The post_device
+ * function is empty since cbmem was initialized early in ramstage. */
+void init_cbmem_pre_device(void)
+{
+	cbmem_initialize();
+#if CONFIG_CONSOLE_CBMEM
+	cbmemc_reinit();
+#endif /* CONFIG_CONSOLE_CBMEM */
+}
+
+void init_cbmem_post_device(void) {}
+
+void cbmem_add_lb_mem(struct lb_memory *mem)
+{
+	unsigned long base;
+	unsigned long top;
+
+	base = (unsigned long)cbmem_base();
+	top = (unsigned long)get_top_aligned();
+	lb_add_memory_range(mem, LB_MEM_TABLE, base, top - base);
+}
+
+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/hardwaremain.c b/src/lib/hardwaremain.c
index b29cc93e79..bc18989ba0 100644
--- a/src/lib/hardwaremain.c
+++ b/src/lib/hardwaremain.c
@@ -94,6 +94,7 @@ void hardwaremain(int boot_complete)
 	    !cbmem_get_table_location(&high_tables_base, &high_tables_size))
 		cbmem_initialize();
 #endif
+	init_cbmem_pre_device();
 
 	timestamp_stash(TS_DEVICE_ENUMERATE);
 
@@ -121,10 +122,8 @@ void hardwaremain(int boot_complete)
 
 	timestamp_stash(TS_DEVICE_DONE);
 
-	cbmem_initialize();
-#if CONFIG_CONSOLE_CBMEM
-	cbmemc_reinit();
-#endif
+	init_cbmem_post_device();
+
 	timestamp_sync();
 
 #if CONFIG_HAVE_ACPI_RESUME