[RFC PATCH 0/3] CMA: generalize CMA reserved area management code

@@ -283,16 +283,6 @@ config CMA_ALIGNMENT
 
 	  If unsure, leave the default value "8".
 
-config DMA_CMA_AREAS
-	int "Maximum count of the CMA device-private areas"
-	default 7
-	help
-	  CMA allows to create CMA areas for particular devices. This parameter
-	  sets the maximum number of such device private CMA areas in the
-	  system.
-
-	  If unsure, leave the default value "7".
-
 endif
 
 endmenu

@@ -24,23 +24,9 @@
 
 #include <linux/memblock.h>
 #include <linux/err.h>
-#include <linux/mm.h>
-#include <linux/mutex.h>
-#include <linux/page-isolation.h>
 #include <linux/sizes.h>
-#include <linux/slab.h>
-#include <linux/swap.h>
-#include <linux/mm_types.h>
 #include <linux/dma-contiguous.h>
-
-struct cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-	struct mutex	lock;
-};
-
-struct cma *dma_contiguous_default_area;
+#include <linux/cma.h>
 
 #ifdef CONFIG_CMA_SIZE_MBYTES
 #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES

@@ -48,6 +34,8 @@ struct cma *dma_contiguous_default_area;
 #define CMA_SIZE_MBYTES 0
 #endif
 
+struct cma *dma_contiguous_default_area;
+
 /*
  * Default global CMA area size can be defined in kernel's .config.
  * This is useful mainly for distro maintainers to create a kernel

@@ -154,55 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 	}
 }
 
-static DEFINE_MUTEX(cma_mutex);
-
-static int __init cma_activate_area(struct cma *cma)
-{
-	int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
-	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
-	unsigned i = cma->count >> pageblock_order;
-	struct zone *zone;
-
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-
-	mutex_init(&cma->lock);
-	return 0;
-}
-
-static struct cma cma_areas[MAX_DMA_CMA_AREAS];
-static unsigned cma_area_count;
-
-static int __init cma_init_reserved_areas(void)
-{
-	int i;
-
-	for (i = 0; i < cma_area_count; i++) {
-		int ret = cma_activate_area(&cma_areas[i]);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-core_initcall(cma_init_reserved_areas);
-
 /**
  * dma_contiguous_reserve_area() - reserve custom contiguous area
  * @size: Size of the reserved area (in bytes),

@@ -224,176 +163,31 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
 				       phys_addr_t limit, struct cma **res_cma,
 				       bool fixed)
 {
-	struct cma *cma = &cma_areas[cma_area_count];
-	phys_addr_t alignment;
-	int ret = 0;
-
-	pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
-		 (unsigned long)size, (unsigned long)base,
-		 (unsigned long)limit);
-
-	/* Sanity checks */
-	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
-		pr_err("Not enough slots for CMA reserved regions!\n");
-		return -ENOSPC;
-	}
-
-	if (!size)
-		return -EINVAL;
-
-	/* Sanitise input arguments */
-	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
-	base = ALIGN(base, alignment);
-	size = ALIGN(size, alignment);
-	limit &= ~(alignment - 1);
-
-	/* Reserve memory */
-	if (base && fixed) {
-		if (memblock_is_region_reserved(base, size) ||
-		    memblock_reserve(base, size) < 0) {
-			ret = -EBUSY;
-			goto err;
-		}
-	} else {
-		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
-							limit);
-		if (!addr) {
-			ret = -ENOMEM;
-			goto err;
-		} else {
-			base = addr;
-		}
-	}
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = PFN_DOWN(base);
-	cma->count = size >> PAGE_SHIFT;
-	*res_cma = cma;
-	cma_area_count++;
+	int ret;
+	struct cma *cma;
 
-	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
-		(unsigned long)base);
+	ret = cma_declare_contiguous(size, base, limit, 0, 0, fixed, &cma);
+	if (ret)
+		return ret;
 
 	/* Architecture specific contiguous memory fixup. */
 	dma_contiguous_early_fixup(base, size);
-	return 0;
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return ret;
-}
+	*res_cma = cma;
 
-static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
-	mutex_lock(&cma->lock);
-	bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
-	mutex_unlock(&cma->lock);
+	return 0;
 }
 
-/**
- * dma_alloc_from_contiguous() - allocate pages from contiguous area
- * @dev:   Pointer to device for which the allocation is performed.
- * @count: Requested number of pages.
- * @align: Requested alignment of pages (in PAGE_SIZE order).
- *
- * This function allocates memory buffer for specified device. It uses
- * device specific contiguous memory area if available or the default
- * global one. Requires architecture specific dev_get_cma_area() helper
- * function.
- */
 struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 				       unsigned int align)
 {
-	unsigned long mask, pfn, pageno, start = 0;
-	struct cma *cma = dev_get_cma_area(dev);
-	struct page *page = NULL;
-	int ret;
-
-	if (!cma || !cma->count)
-		return NULL;
-
 	if (align > CONFIG_CMA_ALIGNMENT)
 		align = CONFIG_CMA_ALIGNMENT;
 
-	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
-		 count, align);
-
-	if (!count)
-		return NULL;
-
-	mask = (1 << align) - 1;
-
-
-	for (;;) {
-		mutex_lock(&cma->lock);
-		pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
-						    start, count, mask);
-		if (pageno >= cma->count) {
-			mutex_unlock(&cma->lock);
-			break;
-		}
-		bitmap_set(cma->bitmap, pageno, count);
-		/*
-		 * It's safe to drop the lock here. We've marked this region for
-		 * our exclusive use. If the migration fails we will take the
-		 * lock again and unmark it.
-		 */
-		mutex_unlock(&cma->lock);
-
-		pfn = cma->base_pfn + pageno;
-		mutex_lock(&cma_mutex);
-		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
-		mutex_unlock(&cma_mutex);
-		if (ret == 0) {
-			page = pfn_to_page(pfn);
-			break;
-		} else if (ret != -EBUSY) {
-			clear_cma_bitmap(cma, pfn, count);
-			break;
-		}
-		clear_cma_bitmap(cma, pfn, count);
-		pr_debug("%s(): memory range at %p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
-	}
-
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
+	return cma_alloc(dev_get_cma_area(dev), count, align);
 }
 
-/**
- * dma_release_from_contiguous() - release allocated pages
- * @dev:   Pointer to device for which the pages were allocated.
- * @pages: Allocated pages.
- * @count: Number of allocated pages.
- *
- * This function releases memory allocated by dma_alloc_from_contiguous().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
- */
 bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 				 int count)
 {
-	struct cma *cma = dev_get_cma_area(dev);
-	unsigned long pfn;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p)\n", __func__, (void *)pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
-
-	free_contig_range(pfn, count);
-	clear_cma_bitmap(cma, pfn, count);
-
-	return true;
+	return cma_release(dev_get_cma_area(dev), pages, count);
 }

@@ -53,9 +53,10 @@
 
 #ifdef __KERNEL__
 
+#include <linux/device.h>
+
 struct cma;
 struct page;
-struct device;
 
 #ifdef CONFIG_DMA_CMA
 

@@ -15,12 +15,14 @@
 #include <linux/init.h>
 #include <linux/memblock.h>
 #include <linux/sizes.h>
+#include <linux/cma.h>
 
 #include <asm/cputable.h>
 #include <asm/kvm_ppc.h>
 #include <asm/kvm_book3s.h>
 
-#include "book3s_hv_cma.h"
+#define KVM_CMA_CHUNK_ORDER	18
+
 /*
  * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
  * should be power of 2.

@@ -42,6 +44,8 @@ static unsigned long kvm_cma_resv_ratio = 5;
 unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT;	/* 128MB */
 EXPORT_SYMBOL_GPL(kvm_rma_pages);
 
+static struct cma *kvm_cma;
+
 /* Work out RMLS (real mode limit selector) field value for a given RMA size.
    Assumes POWER7 or PPC970. */
 static inline int lpcr_rmls(unsigned long rma_size)

@@ -96,7 +100,7 @@ struct kvm_rma_info *kvm_alloc_rma()
 	ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
 	if (!ri)
 		return NULL;
-	page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
+	page = cma_alloc(kvm_cma, kvm_rma_pages, get_order(kvm_rma_pages));
 	if (!page)
 		goto err_out;
 	atomic_set(&ri->use_count, 1);

@@ -111,7 +115,7 @@ EXPORT_SYMBOL_GPL(kvm_alloc_rma);
 void kvm_release_rma(struct kvm_rma_info *ri)
 {
 	if (atomic_dec_and_test(&ri->use_count)) {
-		kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
+		cma_release(kvm_cma, pfn_to_page(ri->base_pfn), kvm_rma_pages);
 		kfree(ri);
 	}
 }

@@ -133,13 +137,13 @@ struct page *kvm_alloc_hpt(unsigned long nr_pages)
 	/* Old CPUs require HPT aligned on a multiple of its size */
 	if (!cpu_has_feature(CPU_FTR_ARCH_206))
 		align_pages = nr_pages;
-	return kvm_alloc_cma(nr_pages, align_pages);
+	return cma_alloc(kvm_cma, nr_pages, get_order(align_pages));
 }
 EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
 
 void kvm_release_hpt(struct page *page, unsigned long nr_pages)
 {
-	kvm_release_cma(page, nr_pages);
+	cma_release(kvm_cma, page, nr_pages);
 }
 EXPORT_SYMBOL_GPL(kvm_release_hpt);
 

@@ -178,6 +182,7 @@ void __init kvm_cma_reserve(void)
 			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
 
 		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
-		kvm_cma_declare_contiguous(selected_size, align_size);
+		cma_declare_contiguous(selected_size, 0, 0, align_size,
+			KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma);
 	}
 }

@@ -1,240 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * 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; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-#define pr_fmt(fmt) "kvm_cma: " fmt
-
-#ifdef CONFIG_CMA_DEBUG
-#ifndef DEBUG
-#  define DEBUG
-#endif
-#endif
-
-#include <linux/memblock.h>
-#include <linux/mutex.h>
-#include <linux/sizes.h>
-#include <linux/slab.h>
-
-#include "book3s_hv_cma.h"
-
-struct kvm_cma {
-	unsigned long	base_pfn;
-	unsigned long	count;
-	unsigned long	*bitmap;
-};
-
-static DEFINE_MUTEX(kvm_cma_mutex);
-static struct kvm_cma kvm_cma_area;
-
-/**
- * kvm_cma_declare_contiguous() - reserve area for contiguous memory handling
- *			          for kvm hash pagetable
- * @size:  Size of the reserved memory.
- * @alignment:  Alignment for the contiguous memory area
- *
- * This function reserves memory for kvm cma area. It should be
- * called by arch code when early allocator (memblock or bootmem)
- * is still activate.
- */
-long __init kvm_cma_declare_contiguous(phys_addr_t size, phys_addr_t alignment)
-{
-	long base_pfn;
-	phys_addr_t addr;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s(size %lx)\n", __func__, (unsigned long)size);
-
-	if (!size)
-		return -EINVAL;
-	/*
-	 * Sanitise input arguments.
-	 * We should be pageblock aligned for CMA.
-	 */
-	alignment = max(alignment, (phys_addr_t)(PAGE_SIZE << pageblock_order));
-	size = ALIGN(size, alignment);
-	/*
-	 * Reserve memory
-	 * Use __memblock_alloc_base() since
-	 * memblock_alloc_base() panic()s.
-	 */
-	addr = __memblock_alloc_base(size, alignment, 0);
-	if (!addr) {
-		base_pfn = -ENOMEM;
-		goto err;
-	} else
-		base_pfn = PFN_DOWN(addr);
-
-	/*
-	 * Each reserved area must be initialised later, when more kernel
-	 * subsystems (like slab allocator) are available.
-	 */
-	cma->base_pfn = base_pfn;
-	cma->count    = size >> PAGE_SHIFT;
-	pr_info("CMA: reserved %ld MiB\n", (unsigned long)size / SZ_1M);
-	return 0;
-err:
-	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
-	return base_pfn;
-}
-
-/**
- * kvm_alloc_cma() - allocate pages from contiguous area
- * @nr_pages: Requested number of pages.
- * @align_pages: Requested alignment in number of pages
- *
- * This function allocates memory buffer for hash pagetable.
- */
-struct page *kvm_alloc_cma(unsigned long nr_pages, unsigned long align_pages)
-{
-	int ret;
-	struct page *page = NULL;
-	struct kvm_cma *cma = &kvm_cma_area;
-	unsigned long chunk_count, nr_chunk;
-	unsigned long mask, pfn, pageno, start = 0;
-
-
-	if (!cma || !cma->count)
-		return NULL;
-
-	pr_debug("%s(cma %p, count %lu, align pages %lu)\n", __func__,
-		 (void *)cma, nr_pages, align_pages);
-
-	if (!nr_pages)
-		return NULL;
-	/*
-	 * align mask with chunk size. The bit tracks pages in chunk size
-	 */
-	VM_BUG_ON(!is_power_of_2(align_pages));
-	mask = (align_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT)) - 1;
-	BUILD_BUG_ON(PAGE_SHIFT > KVM_CMA_CHUNK_ORDER);
-
-	chunk_count = cma->count >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	nr_chunk = nr_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	for (;;) {
-		pageno = bitmap_find_next_zero_area(cma->bitmap, chunk_count,
-						    start, nr_chunk, mask);
-		if (pageno >= chunk_count)
-			break;
-
-		pfn = cma->base_pfn + (pageno << (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT));
-		ret = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_CMA);
-		if (ret == 0) {
-			bitmap_set(cma->bitmap, pageno, nr_chunk);
-			page = pfn_to_page(pfn);
-			memset(pfn_to_kaddr(pfn), 0, nr_pages << PAGE_SHIFT);
-			break;
-		} else if (ret != -EBUSY) {
-			break;
-		}
-		pr_debug("%s(): memory range at %p is busy, retrying\n",
-			 __func__, pfn_to_page(pfn));
-		/* try again with a bit different memory target */
-		start = pageno + mask + 1;
-	}
-	mutex_unlock(&kvm_cma_mutex);
-	pr_debug("%s(): returned %p\n", __func__, page);
-	return page;
-}
-
-/**
- * kvm_release_cma() - release allocated pages for hash pagetable
- * @pages: Allocated pages.
- * @nr_pages: Number of allocated pages.
- *
- * This function releases memory allocated by kvm_alloc_cma().
- * It returns false when provided pages do not belong to contiguous area and
- * true otherwise.
- */
-bool kvm_release_cma(struct page *pages, unsigned long nr_pages)
-{
-	unsigned long pfn;
-	unsigned long nr_chunk;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	if (!cma || !pages)
-		return false;
-
-	pr_debug("%s(page %p count %lu)\n", __func__, (void *)pages, nr_pages);
-
-	pfn = page_to_pfn(pages);
-
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
-	VM_BUG_ON(pfn + nr_pages > cma->base_pfn + cma->count);
-	nr_chunk = nr_pages >>  (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-
-	mutex_lock(&kvm_cma_mutex);
-	bitmap_clear(cma->bitmap,
-		     (pfn - cma->base_pfn) >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT),
-		     nr_chunk);
-	free_contig_range(pfn, nr_pages);
-	mutex_unlock(&kvm_cma_mutex);
-
-	return true;
-}
-
-static int __init kvm_cma_activate_area(unsigned long base_pfn,
-					unsigned long count)
-{
-	unsigned long pfn = base_pfn;
-	unsigned i = count >> pageblock_order;
-	struct zone *zone;
-
-	WARN_ON_ONCE(!pfn_valid(pfn));
-	zone = page_zone(pfn_to_page(pfn));
-	do {
-		unsigned j;
-		base_pfn = pfn;
-		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			WARN_ON_ONCE(!pfn_valid(pfn));
-			/*
-			 * alloc_contig_range requires the pfn range
-			 * specified to be in the same zone. Make this
-			 * simple by forcing the entire CMA resv range
-			 * to be in the same zone.
-			 */
-			if (page_zone(pfn_to_page(pfn)) != zone)
-				return -EINVAL;
-		}
-		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
-	} while (--i);
-	return 0;
-}
-
-static int __init kvm_cma_init_reserved_areas(void)
-{
-	int bitmap_size, ret;
-	unsigned long chunk_count;
-	struct kvm_cma *cma = &kvm_cma_area;
-
-	pr_debug("%s()\n", __func__);
-	if (!cma->count)
-		return 0;
-	chunk_count = cma->count >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
-	bitmap_size = BITS_TO_LONGS(chunk_count) * sizeof(long);
-	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-	if (!cma->bitmap)
-		return -ENOMEM;
-
-	ret = kvm_cma_activate_area(cma->base_pfn, cma->count);
-	if (ret)
-		goto error;
-	return 0;
-
-error:
-	kfree(cma->bitmap);
-	return ret;
-}
-core_initcall(kvm_cma_init_reserved_areas);

@@ -1,27 +0,0 @@
-/*
- * Contiguous Memory Allocator for ppc KVM hash pagetable  based on CMA
- * for DMA mapping framework
- *
- * Copyright IBM Corporation, 2013
- * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
- *
- * 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; either version 2 of the
- * License or (at your optional) any later version of the license.
- *
- */
-
-#ifndef __POWERPC_KVM_CMA_ALLOC_H__
-#define __POWERPC_KVM_CMA_ALLOC_H__
-/*
- * Both RMA and Hash page allocation will be multiple of 256K.
- */
-#define KVM_CMA_CHUNK_ORDER	18
-
-extern struct page *kvm_alloc_cma(unsigned long nr_pages,
-				  unsigned long align_pages);
-extern bool kvm_release_cma(struct page *pages, unsigned long nr_pages);
-extern long kvm_cma_declare_contiguous(phys_addr_t size,
-				       phys_addr_t alignment) __init;
-#endif

@@ -283,7 +283,7 @@ config CMA_ALIGNMENT
 
 	  If unsure, leave the default value "8".
 
-config CMA_AREAS
+config DMA_CMA_AREAS
 	int "Maximum count of the CMA device-private areas"
 	default 7
 	help

@@ -186,7 +186,7 @@ static int __init cma_activate_area(struct cma *cma)
 	return 0;
 }
 
-static struct cma cma_areas[MAX_CMA_AREAS];
+static struct cma cma_areas[MAX_DMA_CMA_AREAS];
 static unsigned cma_area_count;
 
 static int __init cma_init_reserved_areas(void)

@@ -0,0 +1,28 @@
+/*
+ * Contiguous Memory Allocator
+ *
+ * Copyright LG Electronics Inc., 2014
+ * Written by:
+ *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
+ *
+ * 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; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ *
+ */
+
+#ifndef __CMA_H__
+#define __CMA_H__
+
+struct cma;
+
+extern struct page *cma_alloc(struct cma *cma, unsigned long count,
+				unsigned long align);
+extern bool cma_release(struct cma *cma, struct page *pages,
+				unsigned long count);
+extern int __init cma_declare_contiguous(phys_addr_t size, phys_addr_t base,
+				phys_addr_t limit, phys_addr_t alignment,
+				unsigned long bitmap_shift, bool fixed,
+				struct cma **res_cma);
+#endif

@@ -63,7 +63,7 @@ struct device;
  * There is always at least global CMA area and a few optional device
  * private areas configured in kernel .config.
  */
-#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+#define MAX_DMA_CMA_AREAS  (1 + CONFIG_DMA_CMA_AREAS)
 
 extern struct cma *dma_contiguous_default_area;
 

@@ -123,7 +123,7 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 
 #else
 
-#define MAX_CMA_AREAS	(0)
+#define MAX_DMA_CMA_AREAS	(0)
 
 static inline struct cma *dev_get_cma_area(struct device *dev)
 {

@@ -515,6 +515,17 @@ config CMA_DEBUG
 	  processing calls such as dma_alloc_from_contiguous().
 	  This option does not affect warning and error messages.
 
+config CMA_AREAS
+	int "Maximum count of the CMA areas"
+	depends on CMA
+	default 7
+	help
+	  CMA allows to create CMA areas for particular purpose, mainly,
+	  used as device private area. This parameter sets the maximum
+	  number of CMA area in the system.
+
+	  If unsure, leave the default value "7".
+
 config ZBUD
 	tristate
 	default n

@@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
 obj-$(CONFIG_ZBUD)	+= zbud.o
 obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
 obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
+obj-$(CONFIG_CMA)	+= cma.o

@@ -0,0 +1,329 @@
+/*
+ * Contiguous Memory Allocator
+ *
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Copyright IBM Corporation, 2013
+ * Copyright LG Electronics Inc., 2014
+ * Written by:
+ *	Marek Szyprowski <m.szyprowski@samsung.com>
+ *	Michal Nazarewicz <mina86@mina86.com>
+ *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
+ *
+ * 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; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ */
+
+#define pr_fmt(fmt) "cma: " fmt
+
+#ifdef CONFIG_CMA_DEBUG
+#ifndef DEBUG
+#  define DEBUG
+#endif
+#endif
+
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+
+struct cma {
+	unsigned long	base_pfn;
+	unsigned long	count;
+	unsigned long	*bitmap;
+	unsigned long	bitmap_shift;
+	struct mutex	lock;
+};
+
+/*
+ * There is always at least global CMA area and a few optional
+ * areas configured in kernel .config.
+ */
+#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+
+static struct cma cma_areas[MAX_CMA_AREAS];
+static unsigned cma_area_count;
+static DEFINE_MUTEX(cma_mutex);
+
+static unsigned long cma_bitmap_mask(struct cma *cma,
+				unsigned long align_order)
+{
+	return (1 << (align_order >> cma->bitmap_shift)) - 1;
+}
+
+static unsigned long cma_bitmap_max_no(struct cma *cma)
+{
+	return cma->count >> cma->bitmap_shift;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+						unsigned long pages)
+{
+	return ALIGN(pages, 1 << cma->bitmap_shift) >> cma->bitmap_shift;
+}
+
+static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+	unsigned long bitmapno, nr_bits;
+
+	bitmapno = (pfn - cma->base_pfn) >> cma->bitmap_shift;
+	nr_bits = cma_bitmap_pages_to_bits(cma, count);
+
+	mutex_lock(&cma->lock);
+	bitmap_clear(cma->bitmap, bitmapno, nr_bits);
+	mutex_unlock(&cma->lock);
+}
+
+static int __init cma_activate_area(struct cma *cma)
+{
+	int max_bitmapno = cma_bitmap_max_no(cma);
+	int bitmap_size = BITS_TO_LONGS(max_bitmapno) * sizeof(long);
+	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
+	unsigned i = cma->count >> pageblock_order;
+	struct zone *zone;
+
+	pr_debug("%s()\n", __func__);
+	if (!cma->count)
+		return 0;
+
+	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+	if (!cma->bitmap)
+		return -ENOMEM;
+
+	WARN_ON_ONCE(!pfn_valid(pfn));
+	zone = page_zone(pfn_to_page(pfn));
+
+	do {
+		unsigned j;
+
+		base_pfn = pfn;
+		for (j = pageblock_nr_pages; j; --j, pfn++) {
+			WARN_ON_ONCE(!pfn_valid(pfn));
+			/*
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
+			 */
+			if (page_zone(pfn_to_page(pfn)) != zone)
+				goto err;
+		}
+		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
+	} while (--i);
+
+	mutex_init(&cma->lock);
+	return 0;
+
+err:
+	kfree(cma->bitmap);
+	return -EINVAL;
+}
+
+static int __init cma_init_reserved_areas(void)
+{
+	int i;
+
+	for (i = 0; i < cma_area_count; i++) {
+		int ret = cma_activate_area(&cma_areas[i]);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+core_initcall(cma_init_reserved_areas);
+
+/**
+ * cma_declare_contiguous() - reserve custom contiguous area
+ * @size: Size of the reserved area (in bytes),
+ * @base: Base address of the reserved area optional, use 0 for any
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ * @bitmap_shift: Order of pages represented by one bit on bitmap.
+ * @fixed: hint about where to place the reserved area
+ * @res_cma: Pointer to store the created cma region.
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory. This function allows to create custom reserved areas.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base.  If false,
+ * reserve in range from @base to @limit.
+ */
+int __init cma_declare_contiguous(phys_addr_t size, phys_addr_t base,
+				phys_addr_t limit, phys_addr_t alignment,
+				unsigned long bitmap_shift, bool fixed,
+				struct cma **res_cma)
+{
+	struct cma *cma = &cma_areas[cma_area_count];
+	int ret = 0;
+
+	pr_debug("%s(size %lx, base %08lx, limit %08lx, alignment %08lx)\n",
+			__func__, (unsigned long)size, (unsigned long)base,
+			(unsigned long)limit, (unsigned long)alignment);
+
+	/* Sanity checks */
+	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
+		pr_err("Not enough slots for CMA reserved regions!\n");
+		return -ENOSPC;
+	}
+
+	if (!size)
+		return -EINVAL;
+
+	/*
+	 * Sanitise input arguments.
+	 * CMA area should be at least MAX_ORDER - 1 aligned. Otherwise,
+	 * CMA area could be merged into other MIGRATE_TYPE by buddy mechanism
+	 * and CMA property will be broken.
+	 */
+	alignment >>= PAGE_SHIFT;
+	alignment = PAGE_SIZE << max3(MAX_ORDER - 1, pageblock_order,
+						(int)alignment);
+	base = ALIGN(base, alignment);
+	size = ALIGN(size, alignment);
+	limit &= ~(alignment - 1);
+	/* size should be aligned with bitmap_shift */
+	BUG_ON(!IS_ALIGNED(size >> PAGE_SHIFT, 1 << cma->bitmap_shift));
+
+	/* Reserve memory */
+	if (base && fixed) {
+		if (memblock_is_region_reserved(base, size) ||
+		    memblock_reserve(base, size) < 0) {
+			ret = -EBUSY;
+			goto err;
+		}
+	} else {
+		phys_addr_t addr = memblock_alloc_range(size, alignment, base,
+							limit);
+		if (!addr) {
+			ret = -ENOMEM;
+			goto err;
+		} else {
+			base = addr;
+		}
+	}
+
+	/*
+	 * Each reserved area must be initialised later, when more kernel
+	 * subsystems (like slab allocator) are available.
+	 */
+	cma->base_pfn = PFN_DOWN(base);
+	cma->count = size >> PAGE_SHIFT;
+	cma->bitmap_shift = bitmap_shift;
+	*res_cma = cma;
+	cma_area_count++;
+
+	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+		(unsigned long)base);
+
+	return 0;
+
+err:
+	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+	return ret;
+}
+
+/**
+ * cma_alloc() - allocate pages from contiguous area
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
+ *
+ * This function allocates part of contiguous memory on specific
+ * contiguous memory area.
+ */
+struct page *cma_alloc(struct cma *cma, unsigned long count,
+				       unsigned long align)
+{
+	unsigned long mask, pfn, start = 0;
+	unsigned long max_bitmapno, bitmapno, nr_bits;
+	struct page *page = NULL;
+	int ret;
+
+	if (!cma || !cma->count)
+		return NULL;
+
+	pr_debug("%s(cma %p, count %ld, align %ld)\n", __func__, (void *)cma,
+		 count, align);
+
+	if (!count)
+		return NULL;
+
+	mask = cma_bitmap_mask(cma, align);
+	max_bitmapno = cma_bitmap_max_no(cma);
+	nr_bits = cma_bitmap_pages_to_bits(cma, count);
+
+	for (;;) {
+		mutex_lock(&cma->lock);
+		bitmapno = bitmap_find_next_zero_area(cma->bitmap,
+					max_bitmapno, start, nr_bits, mask);
+		if (bitmapno >= max_bitmapno) {
+			mutex_unlock(&cma->lock);
+			break;
+		}
+		bitmap_set(cma->bitmap, bitmapno, nr_bits);
+		/*
+		 * It's safe to drop the lock here. We've marked this region for
+		 * our exclusive use. If the migration fails we will take the
+		 * lock again and unmark it.
+		 */
+		mutex_unlock(&cma->lock);
+
+		pfn = cma->base_pfn + (bitmapno << cma->bitmap_shift);
+		mutex_lock(&cma_mutex);
+		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
+		mutex_unlock(&cma_mutex);
+		if (ret == 0) {
+			page = pfn_to_page(pfn);
+			break;
+		}
+		clear_cma_bitmap(cma, pfn, count);
+		if (ret != -EBUSY)
+			break;
+
+		pr_debug("%s(): memory range at %p is busy, retrying\n",
+			 __func__, pfn_to_page(pfn));
+		/* try again with a bit different memory target */
+		start = bitmapno + mask + 1;
+	}
+
+	pr_debug("%s(): returned %p\n", __func__, page);
+	return page;
+}
+
+/**
+ * cma_release() - release allocated pages
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by alloc_cma().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool cma_release(struct cma *cma, struct page *pages, unsigned long count)
+{
+	unsigned long pfn;
+
+	if (!cma || !pages)
+		return false;
+
+	pr_debug("%s(page %p)\n", __func__, (void *)pages);
+
+	pfn = page_to_pfn(pages);
+	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
+		return false;
+
+	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
+
+	free_contig_range(pfn, count);
+	clear_cma_bitmap(cma, pfn, count);
+
+	return true;
+}