soc: qualcomm: Add Shared Memory Manager driver

The Shared Memory Manager driver implements an interface for allocating
and accessing items in the memory area shared among all of the
processors in a Qualcomm platform.

Adapted from the Linux driver (4.17)

Changes from the original Linux driver:
* Removed HW spinlock mechanism, which is irrelevant
in U-boot particualar use case, which is just reading from the smem.
* Adapted from Linux driver model to U-Boot's.

Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Ramon Fried <ramon.fried@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

3 files changed, 946 insertions, 0 deletions

diff --git a/drivers/smem/Kconfig b/drivers/smem/Kconfig
index 64337a8b8ea..6cf5a4e61e3 100644
--- a/drivers/smem/Kconfig
+++ b/drivers/smem/Kconfig
@@ -1,2 +1,15 @@
 menuconfig SMEM
 	bool  "SMEM (Shared Memory mamanger) support"
+
+if SMEM
+
+config MSM_SMEM
+    bool "Qualcomm Shared Memory Manager (SMEM)"
+    depends on DM
+    depends on ARCH_SNAPDRAGON
+    help
+      Enable support for the Qualcomm Shared Memory Manager.
+      The driver provides an interface to items in a heap shared among all
+      processors in a Qualcomm platform.
+
+endif # menu "SMEM Support"
diff --git a/drivers/smem/Makefile b/drivers/smem/Makefile
index ca55c4512de..605b8fc290a 100644
--- a/drivers/smem/Makefile
+++ b/drivers/smem/Makefile
@@ -3,3 +3,4 @@
 # Makefile for the U-Boot SMEM interface drivers
 
 obj-$(CONFIG_SMEM) += smem-uclass.o
+obj-$(CONFIG_MSM_SMEM) += msm_smem.o
diff --git a/drivers/smem/msm_smem.c b/drivers/smem/msm_smem.c
new file mode 100644
index 00000000000..9fa653ad28b
--- /dev/null
+++ b/drivers/smem/msm_smem.c
@@ -0,0 +1,932 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2015, Sony Mobile Communications AB.
+ * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2018, Ramon Fried <ramon.fried@gmail.com>
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <dm.h>
+#include <dm/of_access.h>
+#include <dm/of_addr.h>
+#include <asm/io.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <smem.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * The Qualcomm shared memory system is an allocate-only heap structure that
+ * consists of one of more memory areas that can be accessed by the processors
+ * in the SoC.
+ *
+ * All systems contains a global heap, accessible by all processors in the SoC,
+ * with a table of contents data structure (@smem_header) at the beginning of
+ * the main shared memory block.
+ *
+ * The global header contains meta data for allocations as well as a fixed list
+ * of 512 entries (@smem_global_entry) that can be initialized to reference
+ * parts of the shared memory space.
+ *
+ *
+ * In addition to this global heap, a set of "private" heaps can be set up at
+ * boot time with access restrictions so that only certain processor pairs can
+ * access the data.
+ *
+ * These partitions are referenced from an optional partition table
+ * (@smem_ptable), that is found 4kB from the end of the main smem region. The
+ * partition table entries (@smem_ptable_entry) lists the involved processors
+ * (or hosts) and their location in the main shared memory region.
+ *
+ * Each partition starts with a header (@smem_partition_header) that identifies
+ * the partition and holds properties for the two internal memory regions. The
+ * two regions are cached and non-cached memory respectively. Each region
+ * contain a link list of allocation headers (@smem_private_entry) followed by
+ * their data.
+ *
+ * Items in the non-cached region are allocated from the start of the partition
+ * while items in the cached region are allocated from the end. The free area
+ * is hence the region between the cached and non-cached offsets. The header of
+ * cached items comes after the data.
+ *
+ * Version 12 (SMEM_GLOBAL_PART_VERSION) changes the item alloc/get procedure
+ * for the global heap. A new global partition is created from the global heap
+ * region with partition type (SMEM_GLOBAL_HOST) and the max smem item count is
+ * set by the bootloader.
+ *
+ */
+
+/*
+ * The version member of the smem header contains an array of versions for the
+ * various software components in the SoC. We verify that the boot loader
+ * version is a valid version as a sanity check.
+ */
+#define SMEM_MASTER_SBL_VERSION_INDEX	7
+#define SMEM_GLOBAL_HEAP_VERSION	11
+#define SMEM_GLOBAL_PART_VERSION	12
+
+/*
+ * The first 8 items are only to be allocated by the boot loader while
+ * initializing the heap.
+ */
+#define SMEM_ITEM_LAST_FIXED	8
+
+/* Highest accepted item number, for both global and private heaps */
+#define SMEM_ITEM_COUNT		512
+
+/* Processor/host identifier for the application processor */
+#define SMEM_HOST_APPS		0
+
+/* Processor/host identifier for the global partition */
+#define SMEM_GLOBAL_HOST	0xfffe
+
+/* Max number of processors/hosts in a system */
+#define SMEM_HOST_COUNT		10
+
+/**
+ * struct smem_proc_comm - proc_comm communication struct (legacy)
+ * @command:	current command to be executed
+ * @status:	status of the currently requested command
+ * @params:	parameters to the command
+ */
+struct smem_proc_comm {
+	__le32 command;
+	__le32 status;
+	__le32 params[2];
+};
+
+/**
+ * struct smem_global_entry - entry to reference smem items on the heap
+ * @allocated:	boolean to indicate if this entry is used
+ * @offset:	offset to the allocated space
+ * @size:	size of the allocated space, 8 byte aligned
+ * @aux_base:	base address for the memory region used by this unit, or 0 for
+ *		the default region. bits 0,1 are reserved
+ */
+struct smem_global_entry {
+	__le32 allocated;
+	__le32 offset;
+	__le32 size;
+	__le32 aux_base; /* bits 1:0 reserved */
+};
+#define AUX_BASE_MASK		0xfffffffc
+
+/**
+ * struct smem_header - header found in beginning of primary smem region
+ * @proc_comm:		proc_comm communication interface (legacy)
+ * @version:		array of versions for the various subsystems
+ * @initialized:	boolean to indicate that smem is initialized
+ * @free_offset:	index of the first unallocated byte in smem
+ * @available:		number of bytes available for allocation
+ * @reserved:		reserved field, must be 0
+ * toc:			array of references to items
+ */
+struct smem_header {
+	struct smem_proc_comm proc_comm[4];
+	__le32 version[32];
+	__le32 initialized;
+	__le32 free_offset;
+	__le32 available;
+	__le32 reserved;
+	struct smem_global_entry toc[SMEM_ITEM_COUNT];
+};
+
+/**
+ * struct smem_ptable_entry - one entry in the @smem_ptable list
+ * @offset:	offset, within the main shared memory region, of the partition
+ * @size:	size of the partition
+ * @flags:	flags for the partition (currently unused)
+ * @host0:	first processor/host with access to this partition
+ * @host1:	second processor/host with access to this partition
+ * @cacheline:	alignment for "cached" entries
+ * @reserved:	reserved entries for later use
+ */
+struct smem_ptable_entry {
+	__le32 offset;
+	__le32 size;
+	__le32 flags;
+	__le16 host0;
+	__le16 host1;
+	__le32 cacheline;
+	__le32 reserved[7];
+};
+
+/**
+ * struct smem_ptable - partition table for the private partitions
+ * @magic:	magic number, must be SMEM_PTABLE_MAGIC
+ * @version:	version of the partition table
+ * @num_entries: number of partitions in the table
+ * @reserved:	for now reserved entries
+ * @entry:	list of @smem_ptable_entry for the @num_entries partitions
+ */
+struct smem_ptable {
+	u8 magic[4];
+	__le32 version;
+	__le32 num_entries;
+	__le32 reserved[5];
+	struct smem_ptable_entry entry[];
+};
+
+static const u8 SMEM_PTABLE_MAGIC[] = { 0x24, 0x54, 0x4f, 0x43 }; /* "$TOC" */
+
+/**
+ * struct smem_partition_header - header of the partitions
+ * @magic:	magic number, must be SMEM_PART_MAGIC
+ * @host0:	first processor/host with access to this partition
+ * @host1:	second processor/host with access to this partition
+ * @size:	size of the partition
+ * @offset_free_uncached: offset to the first free byte of uncached memory in
+ *		this partition
+ * @offset_free_cached: offset to the first free byte of cached memory in this
+ *		partition
+ * @reserved:	for now reserved entries
+ */
+struct smem_partition_header {
+	u8 magic[4];
+	__le16 host0;
+	__le16 host1;
+	__le32 size;
+	__le32 offset_free_uncached;
+	__le32 offset_free_cached;
+	__le32 reserved[3];
+};
+
+static const u8 SMEM_PART_MAGIC[] = { 0x24, 0x50, 0x52, 0x54 };
+
+/**
+ * struct smem_private_entry - header of each item in the private partition
+ * @canary:	magic number, must be SMEM_PRIVATE_CANARY
+ * @item:	identifying number of the smem item
+ * @size:	size of the data, including padding bytes
+ * @padding_data: number of bytes of padding of data
+ * @padding_hdr: number of bytes of padding between the header and the data
+ * @reserved:	for now reserved entry
+ */
+struct smem_private_entry {
+	u16 canary; /* bytes are the same so no swapping needed */
+	__le16 item;
+	__le32 size; /* includes padding bytes */
+	__le16 padding_data;
+	__le16 padding_hdr;
+	__le32 reserved;
+};
+#define SMEM_PRIVATE_CANARY	0xa5a5
+
+/**
+ * struct smem_info - smem region info located after the table of contents
+ * @magic:	magic number, must be SMEM_INFO_MAGIC
+ * @size:	size of the smem region
+ * @base_addr:	base address of the smem region
+ * @reserved:	for now reserved entry
+ * @num_items:	highest accepted item number
+ */
+struct smem_info {
+	u8 magic[4];
+	__le32 size;
+	__le32 base_addr;
+	__le32 reserved;
+	__le16 num_items;
+};
+
+static const u8 SMEM_INFO_MAGIC[] = { 0x53, 0x49, 0x49, 0x49 }; /* SIII */
+
+/**
+ * struct smem_region - representation of a chunk of memory used for smem
+ * @aux_base:	identifier of aux_mem base
+ * @virt_base:	virtual base address of memory with this aux_mem identifier
+ * @size:	size of the memory region
+ */
+struct smem_region {
+	u32 aux_base;
+	void __iomem *virt_base;
+	size_t size;
+};
+
+/**
+ * struct qcom_smem - device data for the smem device
+ * @dev:	device pointer
+ * @global_partition:	pointer to global partition when in use
+ * @global_cacheline:	cacheline size for global partition
+ * @partitions:	list of pointers to partitions affecting the current
+ *		processor/host
+ * @cacheline:	list of cacheline sizes for each host
+ * @item_count: max accepted item number
+ * @num_regions: number of @regions
+ * @regions:	list of the memory regions defining the shared memory
+ */
+struct qcom_smem {
+	struct udevice *dev;
+
+	struct smem_partition_header *global_partition;
+	size_t global_cacheline;
+	struct smem_partition_header *partitions[SMEM_HOST_COUNT];
+	size_t cacheline[SMEM_HOST_COUNT];
+	u32 item_count;
+
+	unsigned int num_regions;
+	struct smem_region regions[0];
+};
+
+static struct smem_private_entry *
+phdr_to_last_uncached_entry(struct smem_partition_header *phdr)
+{
+	void *p = phdr;
+
+	return p + le32_to_cpu(phdr->offset_free_uncached);
+}
+
+static void *phdr_to_first_cached_entry(struct smem_partition_header *phdr,
+					size_t cacheline)
+{
+	void *p = phdr;
+
+	return p + le32_to_cpu(phdr->size) - ALIGN(sizeof(*phdr), cacheline);
+}
+
+static void *phdr_to_last_cached_entry(struct smem_partition_header *phdr)
+{
+	void *p = phdr;
+
+	return p + le32_to_cpu(phdr->offset_free_cached);
+}
+
+static struct smem_private_entry *
+phdr_to_first_uncached_entry(struct smem_partition_header *phdr)
+{
+	void *p = phdr;
+
+	return p + sizeof(*phdr);
+}
+
+static struct smem_private_entry *
+uncached_entry_next(struct smem_private_entry *e)
+{
+	void *p = e;
+
+	return p + sizeof(*e) + le16_to_cpu(e->padding_hdr) +
+	       le32_to_cpu(e->size);
+}
+
+static struct smem_private_entry *
+cached_entry_next(struct smem_private_entry *e, size_t cacheline)
+{
+	void *p = e;
+
+	return p - le32_to_cpu(e->size) - ALIGN(sizeof(*e), cacheline);
+}
+
+static void *uncached_entry_to_item(struct smem_private_entry *e)
+{
+	void *p = e;
+
+	return p + sizeof(*e) + le16_to_cpu(e->padding_hdr);
+}
+
+static void *cached_entry_to_item(struct smem_private_entry *e)
+{
+	void *p = e;
+
+	return p - le32_to_cpu(e->size);
+}
+
+/* Pointer to the one and only smem handle */
+static struct qcom_smem *__smem;
+
+static int qcom_smem_alloc_private(struct qcom_smem *smem,
+				   struct smem_partition_header *phdr,
+				   unsigned int item,
+				   size_t size)
+{
+	struct smem_private_entry *hdr, *end;
+	size_t alloc_size;
+	void *cached;
+
+	hdr = phdr_to_first_uncached_entry(phdr);
+	end = phdr_to_last_uncached_entry(phdr);
+	cached = phdr_to_last_cached_entry(phdr);
+
+	while (hdr < end) {
+		if (hdr->canary != SMEM_PRIVATE_CANARY) {
+			dev_err(smem->dev,
+				"Found invalid canary in hosts %d:%d partition\n",
+				phdr->host0, phdr->host1);
+			return -EINVAL;
+		}
+
+		if (le16_to_cpu(hdr->item) == item)
+			return -EEXIST;
+
+		hdr = uncached_entry_next(hdr);
+	}
+
+	/* Check that we don't grow into the cached region */
+	alloc_size = sizeof(*hdr) + ALIGN(size, 8);
+	if ((void *)hdr + alloc_size >= cached) {
+		dev_err(smem->dev, "Out of memory\n");
+		return -ENOSPC;
+	}
+
+	hdr->canary = SMEM_PRIVATE_CANARY;
+	hdr->item = cpu_to_le16(item);
+	hdr->size = cpu_to_le32(ALIGN(size, 8));
+	hdr->padding_data = cpu_to_le16(le32_to_cpu(hdr->size) - size);
+	hdr->padding_hdr = 0;
+
+	/*
+	 * Ensure the header is written before we advance the free offset, so
+	 * that remote processors that does not take the remote spinlock still
+	 * gets a consistent view of the linked list.
+	 */
+	dmb();
+	le32_add_cpu(&phdr->offset_free_uncached, alloc_size);
+
+	return 0;
+}
+
+static int qcom_smem_alloc_global(struct qcom_smem *smem,
+				  unsigned int item,
+				  size_t size)
+{
+	struct smem_global_entry *entry;
+	struct smem_header *header;
+
+	header = smem->regions[0].virt_base;
+	entry = &header->toc[item];
+	if (entry->allocated)
+		return -EEXIST;
+
+	size = ALIGN(size, 8);
+	if (WARN_ON(size > le32_to_cpu(header->available)))
+		return -ENOMEM;
+
+	entry->offset = header->free_offset;
+	entry->size = cpu_to_le32(size);
+
+	/*
+	 * Ensure the header is consistent before we mark the item allocated,
+	 * so that remote processors will get a consistent view of the item
+	 * even though they do not take the spinlock on read.
+	 */
+	dmb();
+	entry->allocated = cpu_to_le32(1);
+
+	le32_add_cpu(&header->free_offset, size);
+	le32_add_cpu(&header->available, -size);
+
+	return 0;
+}
+
+/**
+ * qcom_smem_alloc() - allocate space for a smem item
+ * @host:	remote processor id, or -1
+ * @item:	smem item handle
+ * @size:	number of bytes to be allocated
+ *
+ * Allocate space for a given smem item of size @size, given that the item is
+ * not yet allocated.
+ */
+static int qcom_smem_alloc(unsigned int host, unsigned int item, size_t size)
+{
+	struct smem_partition_header *phdr;
+	int ret;
+
+	if (!__smem)
+		return -EPROBE_DEFER;
+
+	if (item < SMEM_ITEM_LAST_FIXED) {
+		dev_err(__smem->dev,
+			"Rejecting allocation of static entry %d\n", item);
+		return -EINVAL;
+	}
+
+	if (WARN_ON(item >= __smem->item_count))
+		return -EINVAL;
+
+	if (host < SMEM_HOST_COUNT && __smem->partitions[host]) {
+		phdr = __smem->partitions[host];
+		ret = qcom_smem_alloc_private(__smem, phdr, item, size);
+	} else if (__smem->global_partition) {
+		phdr = __smem->global_partition;
+		ret = qcom_smem_alloc_private(__smem, phdr, item, size);
+	} else {
+		ret = qcom_smem_alloc_global(__smem, item, size);
+	}
+
+	return ret;
+}
+
+static void *qcom_smem_get_global(struct qcom_smem *smem,
+				  unsigned int item,
+				  size_t *size)
+{
+	struct smem_header *header;
+	struct smem_region *area;
+	struct smem_global_entry *entry;
+	u32 aux_base;
+	unsigned int i;
+
+	header = smem->regions[0].virt_base;
+	entry = &header->toc[item];
+	if (!entry->allocated)
+		return ERR_PTR(-ENXIO);
+
+	aux_base = le32_to_cpu(entry->aux_base) & AUX_BASE_MASK;
+
+	for (i = 0; i < smem->num_regions; i++) {
+		area = &smem->regions[i];
+
+		if (area->aux_base == aux_base || !aux_base) {
+			if (size != NULL)
+				*size = le32_to_cpu(entry->size);
+			return area->virt_base + le32_to_cpu(entry->offset);
+		}
+	}
+
+	return ERR_PTR(-ENOENT);
+}
+
+static void *qcom_smem_get_private(struct qcom_smem *smem,
+				   struct smem_partition_header *phdr,
+				   size_t cacheline,
+				   unsigned int item,
+				   size_t *size)
+{
+	struct smem_private_entry *e, *end;
+
+	e = phdr_to_first_uncached_entry(phdr);
+	end = phdr_to_last_uncached_entry(phdr);
+
+	while (e < end) {
+		if (e->canary != SMEM_PRIVATE_CANARY)
+			goto invalid_canary;
+
+		if (le16_to_cpu(e->item) == item) {
+			if (size != NULL)
+				*size = le32_to_cpu(e->size) -
+					le16_to_cpu(e->padding_data);
+
+			return uncached_entry_to_item(e);
+		}
+
+		e = uncached_entry_next(e);
+	}
+
+	/* Item was not found in the uncached list, search the cached list */
+
+	e = phdr_to_first_cached_entry(phdr, cacheline);
+	end = phdr_to_last_cached_entry(phdr);
+
+	while (e > end) {
+		if (e->canary != SMEM_PRIVATE_CANARY)
+			goto invalid_canary;
+
+		if (le16_to_cpu(e->item) == item) {
+			if (size != NULL)
+				*size = le32_to_cpu(e->size) -
+					le16_to_cpu(e->padding_data);
+
+			return cached_entry_to_item(e);
+		}
+
+		e = cached_entry_next(e, cacheline);
+	}
+
+	return ERR_PTR(-ENOENT);
+
+invalid_canary:
+	dev_err(smem->dev, "Found invalid canary in hosts %d:%d partition\n",
+			phdr->host0, phdr->host1);
+
+	return ERR_PTR(-EINVAL);
+}
+
+/**
+ * qcom_smem_get() - resolve ptr of size of a smem item
+ * @host:	the remote processor, or -1
+ * @item:	smem item handle
+ * @size:	pointer to be filled out with size of the item
+ *
+ * Looks up smem item and returns pointer to it. Size of smem
+ * item is returned in @size.
+ */
+static void *qcom_smem_get(unsigned int host, unsigned int item, size_t *size)
+{
+	struct smem_partition_header *phdr;
+	size_t cacheln;
+	void *ptr = ERR_PTR(-EPROBE_DEFER);
+
+	if (!__smem)
+		return ptr;
+
+	if (WARN_ON(item >= __smem->item_count))
+		return ERR_PTR(-EINVAL);
+
+	if (host < SMEM_HOST_COUNT && __smem->partitions[host]) {
+		phdr = __smem->partitions[host];
+		cacheln = __smem->cacheline[host];
+		ptr = qcom_smem_get_private(__smem, phdr, cacheln, item, size);
+	} else if (__smem->global_partition) {
+		phdr = __smem->global_partition;
+		cacheln = __smem->global_cacheline;
+		ptr = qcom_smem_get_private(__smem, phdr, cacheln, item, size);
+	} else {
+		ptr = qcom_smem_get_global(__smem, item, size);
+	}
+
+	return ptr;
+
+}
+
+/**
+ * qcom_smem_get_free_space() - retrieve amount of free space in a partition
+ * @host:	the remote processor identifying a partition, or -1
+ *
+ * To be used by smem clients as a quick way to determine if any new
+ * allocations has been made.
+ */
+static int qcom_smem_get_free_space(unsigned int host)
+{
+	struct smem_partition_header *phdr;
+	struct smem_header *header;
+	unsigned int ret;
+
+	if (!__smem)
+		return -EPROBE_DEFER;
+
+	if (host < SMEM_HOST_COUNT && __smem->partitions[host]) {
+		phdr = __smem->partitions[host];
+		ret = le32_to_cpu(phdr->offset_free_cached) -
+		      le32_to_cpu(phdr->offset_free_uncached);
+	} else if (__smem->global_partition) {
+		phdr = __smem->global_partition;
+		ret = le32_to_cpu(phdr->offset_free_cached) -
+		      le32_to_cpu(phdr->offset_free_uncached);
+	} else {
+		header = __smem->regions[0].virt_base;
+		ret = le32_to_cpu(header->available);
+	}
+
+	return ret;
+}
+
+static int qcom_smem_get_sbl_version(struct qcom_smem *smem)
+{
+	struct smem_header *header;
+	__le32 *versions;
+
+	header = smem->regions[0].virt_base;
+	versions = header->version;
+
+	return le32_to_cpu(versions[SMEM_MASTER_SBL_VERSION_INDEX]);
+}
+
+static struct smem_ptable *qcom_smem_get_ptable(struct qcom_smem *smem)
+{
+	struct smem_ptable *ptable;
+	u32 version;
+
+	ptable = smem->regions[0].virt_base + smem->regions[0].size - SZ_4K;
+	if (memcmp(ptable->magic, SMEM_PTABLE_MAGIC, sizeof(ptable->magic)))
+		return ERR_PTR(-ENOENT);
+
+	version = le32_to_cpu(ptable->version);
+	if (version != 1) {
+		dev_err(smem->dev,
+			"Unsupported partition header version %d\n", version);
+		return ERR_PTR(-EINVAL);
+	}
+	return ptable;
+}
+
+static u32 qcom_smem_get_item_count(struct qcom_smem *smem)
+{
+	struct smem_ptable *ptable;
+	struct smem_info *info;
+
+	ptable = qcom_smem_get_ptable(smem);
+	if (IS_ERR_OR_NULL(ptable))
+		return SMEM_ITEM_COUNT;
+
+	info = (struct smem_info *)&ptable->entry[ptable->num_entries];
+	if (memcmp(info->magic, SMEM_INFO_MAGIC, sizeof(info->magic)))
+		return SMEM_ITEM_COUNT;
+
+	return le16_to_cpu(info->num_items);
+}
+
+static int qcom_smem_set_global_partition(struct qcom_smem *smem)
+{
+	struct smem_partition_header *header;
+	struct smem_ptable_entry *entry = NULL;
+	struct smem_ptable *ptable;
+	u32 host0, host1, size;
+	int i;
+
+	ptable = qcom_smem_get_ptable(smem);
+	if (IS_ERR(ptable))
+		return PTR_ERR(ptable);
+
+	for (i = 0; i < le32_to_cpu(ptable->num_entries); i++) {
+		entry = &ptable->entry[i];
+		host0 = le16_to_cpu(entry->host0);
+		host1 = le16_to_cpu(entry->host1);
+
+		if (host0 == SMEM_GLOBAL_HOST && host0 == host1)
+			break;
+	}
+
+	if (!entry) {
+		dev_err(smem->dev, "Missing entry for global partition\n");
+		return -EINVAL;
+	}
+
+	if (!le32_to_cpu(entry->offset) || !le32_to_cpu(entry->size)) {
+		dev_err(smem->dev, "Invalid entry for global partition\n");
+		return -EINVAL;
+	}
+
+	if (smem->global_partition) {
+		dev_err(smem->dev, "Already found the global partition\n");
+		return -EINVAL;
+	}
+
+	header = smem->regions[0].virt_base + le32_to_cpu(entry->offset);
+	host0 = le16_to_cpu(header->host0);
+	host1 = le16_to_cpu(header->host1);
+
+	if (memcmp(header->magic, SMEM_PART_MAGIC, sizeof(header->magic))) {
+		dev_err(smem->dev, "Global partition has invalid magic\n");
+		return -EINVAL;
+	}
+
+	if (host0 != SMEM_GLOBAL_HOST && host1 != SMEM_GLOBAL_HOST) {
+		dev_err(smem->dev, "Global partition hosts are invalid\n");
+		return -EINVAL;
+	}
+
+	if (le32_to_cpu(header->size) != le32_to_cpu(entry->size)) {
+		dev_err(smem->dev, "Global partition has invalid size\n");
+		return -EINVAL;
+	}
+
+	size = le32_to_cpu(header->offset_free_uncached);
+	if (size > le32_to_cpu(header->size)) {
+		dev_err(smem->dev,
+			"Global partition has invalid free pointer\n");
+		return -EINVAL;
+	}
+
+	smem->global_partition = header;
+	smem->global_cacheline = le32_to_cpu(entry->cacheline);
+
+	return 0;
+}
+
+static int qcom_smem_enumerate_partitions(struct qcom_smem *smem,
+					  unsigned int local_host)
+{
+	struct smem_partition_header *header;
+	struct smem_ptable_entry *entry;
+	struct smem_ptable *ptable;
+	unsigned int remote_host;
+	u32 host0, host1;
+	int i;
+
+	ptable = qcom_smem_get_ptable(smem);
+	if (IS_ERR(ptable))
+		return PTR_ERR(ptable);
+
+	for (i = 0; i < le32_to_cpu(ptable->num_entries); i++) {
+		entry = &ptable->entry[i];
+		host0 = le16_to_cpu(entry->host0);
+		host1 = le16_to_cpu(entry->host1);
+
+		if (host0 != local_host && host1 != local_host)
+			continue;
+
+		if (!le32_to_cpu(entry->offset))
+			continue;
+
+		if (!le32_to_cpu(entry->size))
+			continue;
+
+		if (host0 == local_host)
+			remote_host = host1;
+		else
+			remote_host = host0;
+
+		if (remote_host >= SMEM_HOST_COUNT) {
+			dev_err(smem->dev,
+				"Invalid remote host %d\n",
+				remote_host);
+			return -EINVAL;
+		}
+
+		if (smem->partitions[remote_host]) {
+			dev_err(smem->dev,
+				"Already found a partition for host %d\n",
+				remote_host);
+			return -EINVAL;
+		}
+
+		header = smem->regions[0].virt_base + le32_to_cpu(entry->offset);
+		host0 = le16_to_cpu(header->host0);
+		host1 = le16_to_cpu(header->host1);
+
+		if (memcmp(header->magic, SMEM_PART_MAGIC,
+			    sizeof(header->magic))) {
+			dev_err(smem->dev,
+				"Partition %d has invalid magic\n", i);
+			return -EINVAL;
+		}
+
+		if (host0 != local_host && host1 != local_host) {
+			dev_err(smem->dev,
+				"Partition %d hosts are invalid\n", i);
+			return -EINVAL;
+		}
+
+		if (host0 != remote_host && host1 != remote_host) {
+			dev_err(smem->dev,
+				"Partition %d hosts are invalid\n", i);
+			return -EINVAL;
+		}
+
+		if (le32_to_cpu(header->size) != le32_to_cpu(entry->size)) {
+			dev_err(smem->dev,
+				"Partition %d has invalid size\n", i);
+			return -EINVAL;
+		}
+
+		if (le32_to_cpu(header->offset_free_uncached) > le32_to_cpu(header->size)) {
+			dev_err(smem->dev,
+				"Partition %d has invalid free pointer\n", i);
+			return -EINVAL;
+		}
+
+		smem->partitions[remote_host] = header;
+		smem->cacheline[remote_host] = le32_to_cpu(entry->cacheline);
+	}
+
+	return 0;
+}
+
+static int qcom_smem_map_memory(struct qcom_smem *smem, struct udevice *dev,
+				const char *name, int i)
+{
+	struct fdt_resource r;
+	int ret;
+	int node = dev_of_offset(dev);
+
+	ret = fdtdec_lookup_phandle(gd->fdt_blob, node, name);
+	if (ret < 0) {
+		dev_err(dev, "No %s specified\n", name);
+		return -EINVAL;
+	}
+
+	ret = fdt_get_resource(gd->fdt_blob, ret, "reg", 0, &r);
+	if (ret)
+		return ret;
+
+	smem->regions[i].aux_base = (u32)r.start;
+	smem->regions[i].size = fdt_resource_size(&r);
+	smem->regions[i].virt_base = devm_ioremap(dev, r.start, fdt_resource_size(&r));
+	if (!smem->regions[i].virt_base)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int qcom_smem_probe(struct udevice *dev)
+{
+	struct smem_header *header;
+	struct qcom_smem *smem;
+	size_t array_size;
+	int num_regions;
+	u32 version;
+	int ret;
+	int node = dev_of_offset(dev);
+
+	num_regions = 1;
+	if (fdtdec_lookup_phandle(gd->fdt_blob, node, "qcomrpm-msg-ram") >= 0)
+		num_regions++;
+
+	array_size = num_regions * sizeof(struct smem_region);
+	smem = devm_kzalloc(dev, sizeof(*smem) + array_size, GFP_KERNEL);
+	if (!smem)
+		return -ENOMEM;
+
+	smem->dev = dev;
+	smem->num_regions = num_regions;
+
+	ret = qcom_smem_map_memory(smem, dev, "memory-region", 0);
+	if (ret)
+		return ret;
+
+	if (num_regions > 1) {
+		ret = qcom_smem_map_memory(smem, dev,
+					"qcom,rpm-msg-ram", 1);
+		if (ret)
+			return ret;
+	}
+
+	header = smem->regions[0].virt_base;
+	if (le32_to_cpu(header->initialized) != 1 ||
+	    le32_to_cpu(header->reserved)) {
+		dev_err(&pdev->dev, "SMEM is not initialized by SBL\n");
+		return -EINVAL;
+	}
+
+	version = qcom_smem_get_sbl_version(smem);
+	switch (version >> 16) {
+	case SMEM_GLOBAL_PART_VERSION:
+		ret = qcom_smem_set_global_partition(smem);
+		if (ret < 0)
+			return ret;
+		smem->item_count = qcom_smem_get_item_count(smem);
+		break;
+	case SMEM_GLOBAL_HEAP_VERSION:
+		smem->item_count = SMEM_ITEM_COUNT;
+		break;
+	default:
+		dev_err(dev, "Unsupported SMEM version 0x%x\n", version);
+		return -EINVAL;
+	}
+
+	ret = qcom_smem_enumerate_partitions(smem, SMEM_HOST_APPS);
+	if (ret < 0 && ret != -ENOENT)
+		return ret;
+
+	__smem = smem;
+
+	return 0;
+}
+
+static int qcom_smem_remove(struct udevice *dev)
+{
+	__smem = NULL;
+
+	return 0;
+}
+
+const struct udevice_id qcom_smem_of_match[] = {
+	{ .compatible = "qcom,smem" },
+	{ }
+};
+
+static const struct smem_ops msm_smem_ops = {
+	.alloc = qcom_smem_alloc,
+	.get = qcom_smem_get,
+	.get_free_space = qcom_smem_get_free_space,
+};
+
+U_BOOT_DRIVER(qcom_smem) = {
+	.name	= "qcom_smem",
+	.id	= UCLASS_SMEM,
+	.of_match = qcom_smem_of_match,
+	.ops = &msm_smem_ops,
+	.probe = qcom_smem_probe,
+	.remove = qcom_smem_remove,
+};