diff --git a/arch/arm/mach-msm/board-msm8x60.c b/arch/arm/mach-msm/board-msm8x60.c
index 8f42c25..4333cfb 100644
--- a/arch/arm/mach-msm/board-msm8x60.c
+++ b/arch/arm/mach-msm/board-msm8x60.c
@@ -2708,11 +2708,54 @@
 	.dev = { .platform_data = &android_pmem_audio_pdata },
 };
 
+#define PMEM_BUS_WIDTH(_bw) \
+	{ \
+		.vectors = &(struct msm_bus_vectors){ \
+			.src = MSM_BUS_MASTER_AMPSS_M0, \
+			.dst = MSM_BUS_SLAVE_SMI, \
+			.ib = (_bw), \
+			.ab = 0, \
+		}, \
+	.num_paths = 1, \
+	}
+static struct msm_bus_paths pmem_smi_table[] = {
+	[0] = PMEM_BUS_WIDTH(0), /* Off */
+	[1] = PMEM_BUS_WIDTH(1), /* On */
+};
+
+static struct msm_bus_scale_pdata smi_client_pdata = {
+	.usecase = pmem_smi_table,
+	.num_usecases = ARRAY_SIZE(pmem_smi_table),
+	.name = "pmem_smi",
+};
+
+void pmem_request_smi_region(void *data)
+{
+	int bus_id = (int) data;
+
+	msm_bus_scale_client_update_request(bus_id, 1);
+}
+
+void pmem_release_smi_region(void *data)
+{
+	int bus_id = (int) data;
+
+	msm_bus_scale_client_update_request(bus_id, 0);
+}
+
+void *pmem_setup_smi_region(void)
+{
+	return (void *)msm_bus_scale_register_client(&smi_client_pdata);
+}
 static struct android_pmem_platform_data android_pmem_smipool_pdata = {
 	.name = "pmem_smipool",
 	.allocator_type = PMEM_ALLOCATORTYPE_BITMAP,
 	.cached = 0,
 	.memory_type = MEMTYPE_SMI,
+	.request_region = pmem_request_smi_region,
+	.release_region = pmem_release_smi_region,
+	.setup_region = pmem_setup_smi_region,
+	.map_on_demand = 1,
 };
 static struct platform_device android_pmem_smipool_device = {
 	.name = "android_pmem",
diff --git a/drivers/misc/pmem.c b/drivers/misc/pmem.c
index 5063551..df36ad5 100644
--- a/drivers/misc/pmem.c
+++ b/drivers/misc/pmem.c
@@ -216,9 +216,33 @@
 
 	long (*ioctl)(struct file *, unsigned int, unsigned long);
 	int (*release)(struct inode *, struct file *);
+	/* reference count of allocations */
+	atomic_t allocation_cnt;
+	/*
+	 * request function for a region when the allocation count goes
+	 * from 0 -> 1
+	 */
+	void (*mem_request)(void *);
+	/*
+	 * release function for a region when the allocation count goes
+	 * from 1 -> 0
+	 */
+	void (*mem_release)(void *);
+	/*
+	 * private data for the request/release callback
+	 */
+	void *region_data;
+	/*
+	 * map and unmap as needed
+	 */
+	int map_on_demand;
 };
 #define to_pmem_info_id(a) (container_of(a, struct pmem_info, kobj)->id)
 
+static void ioremap_pmem(int id);
+static void pmem_put_region(int id);
+static int pmem_get_region(int id);
+
 static struct pmem_info pmem[PMEM_MAX_DEVICES];
 static int id_count;
 
@@ -522,6 +546,66 @@
 	.default_attrs = pmem_system_attrs,
 };
 
+static int pmem_allocate_from_id(const int id, const unsigned long size,
+						const unsigned int align)
+{
+	int ret;
+	ret = pmem_get_region(id);
+
+	if (ret)
+		return -1;
+
+	ret = pmem[id].allocate(id, size, align);
+
+	if (ret < 0)
+		pmem_put_region(id);
+
+	return ret;
+}
+
+static int pmem_free_from_id(const int id, const int index)
+{
+	pmem_put_region(id);
+	return pmem[id].free(id, index);
+}
+
+static int pmem_get_region(int id)
+{
+	/* Must be called with arena mutex locked */
+	atomic_inc(&pmem[id].allocation_cnt);
+	if (!pmem[id].vbase) {
+		DLOG("PMEMDEBUG: mapping for %s", pmem[id].name);
+		if (pmem[id].mem_request)
+				pmem[id].mem_request(pmem[id].region_data);
+		ioremap_pmem(id);
+	}
+
+	if (pmem[id].vbase) {
+		return 0;
+	} else {
+		if (pmem[id].mem_release)
+			pmem[id].mem_release(pmem[id].region_data);
+		atomic_dec(&pmem[id].allocation_cnt);
+		return 1;
+	}
+}
+
+static void pmem_put_region(int id)
+{
+	/* Must be called with arena mutex locked */
+	if (atomic_dec_and_test(&pmem[id].allocation_cnt)) {
+		DLOG("PMEMDEBUG: unmapping for %s", pmem[id].name);
+		BUG_ON(!pmem[id].vbase);
+		if (pmem[id].map_on_demand) {
+			iounmap(pmem[id].vbase);
+			pmem[id].vbase = NULL;
+			if (pmem[id].mem_release)
+				pmem[id].mem_release(pmem[id].region_data);
+
+		}
+	}
+}
+
 static int get_id(struct file *file)
 {
 	return MINOR(file->f_dentry->d_inode->i_rdev);
@@ -840,7 +924,7 @@
 	/* if it is not a connected file and it has an allocation, free it */
 	if (!(PMEM_FLAGS_CONNECTED & data->flags) && has_allocation(file)) {
 		mutex_lock(&pmem[id].arena_mutex);
-		ret = pmem[id].free(id, data->index);
+		ret = pmem_free_from_id(id, data->index);
 		mutex_unlock(&pmem[id].arena_mutex);
 	}
 
@@ -1516,7 +1600,7 @@
 static int pmem_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct pmem_data *data = file->private_data;
-	int index;
+	int index = -1;
 	unsigned long vma_size =  vma->vm_end - vma->vm_start;
 	int ret = 0, id = get_id(file);
 #if PMEM_DEBUG_MSGS
@@ -1553,7 +1637,7 @@
 	/* if file->private_data == unalloced, alloc*/
 	if (data->index == -1) {
 		mutex_lock(&pmem[id].arena_mutex);
-		index = pmem[id].allocate(id,
+		index = pmem_allocate_from_id(id,
 				vma->vm_end - vma->vm_start,
 				SZ_4K);
 		mutex_unlock(&pmem[id].arena_mutex);
@@ -2353,7 +2437,7 @@
 			}
 
 			mutex_lock(&pmem[id].arena_mutex);
-			data->index = pmem[id].allocate(id,
+			data->index = pmem_allocate_from_id(id,
 					arg,
 					SZ_4K);
 			mutex_unlock(&pmem[id].arena_mutex);
@@ -2400,9 +2484,9 @@
 			}
 
 			mutex_lock(&pmem[id].arena_mutex);
-			data->index = pmem[id].allocate(id,
-					alloc.size,
-					alloc.align);
+			data->index = pmem_allocate_from_id(id,
+				alloc.size,
+				alloc.align);
 			mutex_unlock(&pmem[id].arena_mutex);
 			ret = data->index == -1 ? -ENOMEM :
 				data->index;
@@ -2436,6 +2520,8 @@
 
 static void ioremap_pmem(int id)
 {
+	DLOG("PMEMDEBUG: ioremaping for %s\n", pmem[id].name);
+
 	if (pmem[id].cached)
 		pmem[id].vbase = ioremap_cached(pmem[id].base, pmem[id].size);
 #ifdef ioremap_ext_buffered
@@ -2653,24 +2739,24 @@
 	pmem[id].base = allocate_contiguous_memory_nomap(pmem[id].size,
 		pmem[id].memory_type, PAGE_SIZE);
 
-	if (pmem[id].allocator_type != PMEM_ALLOCATORTYPE_SYSTEM) {
-		ioremap_pmem(id);
-		if (pmem[id].vbase == 0) {
-			pr_err("pmem: ioremap failed for device %s\n",
-				pmem[id].name);
-			goto error_cant_remap;
-		}
-	}
-
 	pr_info("allocating %lu bytes at %p (%lx physical) for %s\n",
 		pmem[id].size, pmem[id].vbase, pmem[id].base, pmem[id].name);
 
 	pmem[id].garbage_pfn = page_to_pfn(alloc_page(GFP_KERNEL));
+	atomic_set(&pmem[id].allocation_cnt, 0);
+	pmem[id].map_on_demand = pdata->map_on_demand;
+
+	if (pdata->setup_region)
+		pmem[id].region_data = pdata->setup_region();
+
+	if (pdata->request_region)
+		pmem[id].mem_request = pdata->request_region;
+
+	if (pdata->release_region)
+		pmem[id].mem_release = pdata->release_region;
 
 	return 0;
 
-error_cant_remap:
-	misc_deregister(&pmem[id].dev);
 err_cant_register_device:
 out_put_kobj:
 	kobject_put(&pmem[id].kobj);
diff --git a/include/linux/android_pmem.h b/include/linux/android_pmem.h
index 91f8f1b..c029196 100644
--- a/include/linux/android_pmem.h
+++ b/include/linux/android_pmem.h
@@ -153,6 +153,24 @@
 	unsigned buffered;
 	/* which memory type (i.e. SMI, EBI1) this PMEM device is backed by */
 	unsigned memory_type;
+	/*
+	 * function to be called when the number of allocations goes from
+	 * 0 -> 1
+	 */
+	void (*request_region)(void *);
+	/*
+	 * function to be called when the number of allocations goes from
+	 * 1 -> 0
+	 */
+	void (*release_region)(void *);
+	/*
+	 * function to be called upon pmem registration
+	 */
+	void *(*setup_region)(void);
+	/*
+	 * indicates that this region should be mapped/unmaped as needed
+	 */
+	int map_on_demand;
 };
 
 int pmem_setup(struct android_pmem_platform_data *pdata,