4 files changed, 345 insertions, 82 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index db23ae4..302f5bf 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -17,7 +17,9 @@
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma-contiguous.h>
 #include <linux/highmem.h>
+#include <linux/memblock.h>
 #include <linux/slab.h>
 
 #include <asm/memory.h>
@@ -26,6 +28,9 @@
 #include <asm/tlbflush.h>
 #include <asm/sizes.h>
 #include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+#include <asm/system_info.h>
+#include <asm/dma-contiguous.h>
 
 #include "mm.h"
 
@@ -56,6 +61,19 @@ static u64 get_coherent_dma_mask(struct device *dev)
 	return mask;
 }
 
+static void __dma_clear_buffer(struct page *page, size_t size)
+{
+	void *ptr;
+	/*
+	 * Ensure that the allocated pages are zeroed, and that any data
+	 * lurking in the kernel direct-mapped region is invalidated.
+	 */
+	ptr = page_address(page);
+	memset(ptr, 0, size);
+	dmac_flush_range(ptr, ptr + size);
+	outer_flush_range(__pa(ptr), __pa(ptr) + size);
+}
+
 /*
  * Allocate a DMA buffer for 'dev' of size 'size' using the
  * specified gfp mask.  Note that 'size' must be page aligned.
@@ -64,23 +82,6 @@ static struct page *__dma_alloc_buffer(struct device *dev, size_t size, gfp_t gf
 {
 	unsigned long order = get_order(size);
 	struct page *page, *p, *e;
-	void *ptr;
-	u64 mask = get_coherent_dma_mask(dev);
-
-#ifdef CONFIG_DMA_API_DEBUG
-	u64 limit = (mask + 1) & ~mask;
-	if (limit && size >= limit) {
-		dev_warn(dev, "coherent allocation too big (requested %#x mask %#llx)\n",
-			size, mask);
-		return NULL;
-	}
-#endif
-
-	if (!mask)
-		return NULL;
-
-	if (mask < 0xffffffffULL)
-		gfp |= GFP_DMA;
 
 	page = alloc_pages(gfp, order);
 	if (!page)
@@ -93,14 +94,7 @@ static struct page *__dma_alloc_buffer(struct device *dev, size_t size, gfp_t gf
 	for (p = page + (size >> PAGE_SHIFT), e = page + (1 << order); p < e; p++)
 		__free_page(p);
 
-	/*
-	 * Ensure that the allocated pages are zeroed, and that any data
-	 * lurking in the kernel direct-mapped region is invalidated.
-	 */
-	ptr = page_address(page);
-	memset(ptr, 0, size);
-	dmac_flush_range(ptr, ptr + size);
-	outer_flush_range(__pa(ptr), __pa(ptr) + size);
+	__dma_clear_buffer(page, size);
 
 	return page;
 }
@@ -170,6 +164,9 @@ static int __init consistent_init(void)
 	unsigned long base = consistent_base;
 	unsigned long num_ptes = (CONSISTENT_END - base) >> PMD_SHIFT;
 
+	if (cpu_architecture() >= CPU_ARCH_ARMv6)
+		return 0;
+
 	consistent_pte = kmalloc(num_ptes * sizeof(pte_t), GFP_KERNEL);
 	if (!consistent_pte) {
 		pr_err("%s: no memory\n", __func__);
@@ -210,9 +207,101 @@ static int __init consistent_init(void)
 
 	return ret;
 }
-
 core_initcall(consistent_init);
 
+static void *__alloc_from_contiguous(struct device *dev, size_t size,
+				     pgprot_t prot, struct page **ret_page);
+
+static struct arm_vmregion_head coherent_head = {
+	.vm_lock	= __SPIN_LOCK_UNLOCKED(&coherent_head.vm_lock),
+	.vm_list	= LIST_HEAD_INIT(coherent_head.vm_list),
+};
+
+size_t coherent_pool_size = DEFAULT_CONSISTENT_DMA_SIZE / 8;
+
+static int __init early_coherent_pool(char *p)
+{
+	coherent_pool_size = memparse(p, &p);
+	return 0;
+}
+early_param("coherent_pool", early_coherent_pool);
+
+/*
+ * Initialise the coherent pool for atomic allocations.
+ */
+static int __init coherent_init(void)
+{
+	pgprot_t prot = pgprot_dmacoherent(pgprot_kernel);
+	size_t size = coherent_pool_size;
+	struct page *page;
+	void *ptr;
+
+	if (cpu_architecture() < CPU_ARCH_ARMv6)
+		return 0;
+
+	ptr = __alloc_from_contiguous(NULL, size, prot, &page);
+	if (ptr) {
+		coherent_head.vm_start = (unsigned long) ptr;
+		coherent_head.vm_end = (unsigned long) ptr + size;
+		printk(KERN_INFO "DMA: preallocated %u KiB pool for atomic coherent allocations\n",
+		       (unsigned)size / 1024);
+		return 0;
+	}
+	printk(KERN_ERR "DMA: failed to allocate %u KiB pool for atomic coherent allocation\n",
+	       (unsigned)size / 1024);
+	return -ENOMEM;
+}
+/*
+ * CMA is activated by core_initcall, so we must be called after it.
+ */
+postcore_initcall(coherent_init);
+
+struct dma_contig_early_reserve {
+	phys_addr_t base;
+	unsigned long size;
+};
+
+static struct dma_contig_early_reserve dma_mmu_remap[MAX_CMA_AREAS] __initdata;
+
+static int dma_mmu_remap_num __initdata;
+
+void __init dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
+{
+	dma_mmu_remap[dma_mmu_remap_num].base = base;
+	dma_mmu_remap[dma_mmu_remap_num].size = size;
+	dma_mmu_remap_num++;
+}
+
+void __init dma_contiguous_remap(void)
+{
+	int i;
+	for (i = 0; i < dma_mmu_remap_num; i++) {
+		phys_addr_t start = dma_mmu_remap[i].base;
+		phys_addr_t end = start + dma_mmu_remap[i].size;
+		struct map_desc map;
+		unsigned long addr;
+
+		if (end > arm_lowmem_limit)
+			end = arm_lowmem_limit;
+		if (start >= end)
+			return;
+
+		map.pfn = __phys_to_pfn(start);
+		map.virtual = __phys_to_virt(start);
+		map.length = end - start;
+		map.type = MT_MEMORY_DMA_READY;
+
+		/*
+		 * Clear previous low-memory mapping
+		 */
+		for (addr = __phys_to_virt(start); addr < __phys_to_virt(end);
+		     addr += PGDIR_SIZE)
+			pmd_clear(pmd_off_k(addr));
+
+		iotable_init(&map, 1);
+	}
+}
+
 static void *
 __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
 	const void *caller)
@@ -319,20 +408,173 @@ static void __dma_free_remap(void *cpu_addr, size_t size)
 	arm_vmregion_free(&consistent_head, c);
 }
 
+static int __dma_update_pte(pte_t *pte, pgtable_t token, unsigned long addr,
+			    void *data)
+{
+	struct page *page = virt_to_page(addr);
+	pgprot_t prot = *(pgprot_t *)data;
+
+	set_pte_ext(pte, mk_pte(page, prot), 0);
+	return 0;
+}
+
+static void __dma_remap(struct page *page, size_t size, pgprot_t prot)
+{
+	unsigned long start = (unsigned long) page_address(page);
+	unsigned end = start + size;
+
+	apply_to_page_range(&init_mm, start, size, __dma_update_pte, &prot);
+	dsb();
+	flush_tlb_kernel_range(start, end);
+}
+
+static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
+				 pgprot_t prot, struct page **ret_page,
+				 const void *caller)
+{
+	struct page *page;
+	void *ptr;
+	page = __dma_alloc_buffer(dev, size, gfp);
+	if (!page)
+		return NULL;
+
+	ptr = __dma_alloc_remap(page, size, gfp, prot, caller);
+	if (!ptr) {
+		__dma_free_buffer(page, size);
+		return NULL;
+	}
+
+	*ret_page = page;
+	return ptr;
+}
+
+static void *__alloc_from_pool(struct device *dev, size_t size,
+			       struct page **ret_page, const void *caller)
+{
+	struct arm_vmregion *c;
+	size_t align;
+
+	if (!coherent_head.vm_start) {
+		printk(KERN_ERR "%s: coherent pool not initialised!\n",
+		       __func__);
+		dump_stack();
+		return NULL;
+	}
+
+	/*
+	 * Align the region allocation - allocations from pool are rather
+	 * small, so align them to their order in pages, minimum is a page
+	 * size. This helps reduce fragmentation of the DMA space.
+	 */
+	align = PAGE_SIZE << get_order(size);
+	c = arm_vmregion_alloc(&coherent_head, align, size, 0, caller);
+	if (c) {
+		void *ptr = (void *)c->vm_start;
+		struct page *page = virt_to_page(ptr);
+		*ret_page = page;
+		return ptr;
+	}
+	return NULL;
+}
+
+static int __free_from_pool(void *cpu_addr, size_t size)
+{
+	unsigned long start = (unsigned long)cpu_addr;
+	unsigned long end = start + size;
+	struct arm_vmregion *c;
+
+	if (start < coherent_head.vm_start || end > coherent_head.vm_end)
+		return 0;
+
+	c = arm_vmregion_find_remove(&coherent_head, (unsigned long)start);
+
+	if ((c->vm_end - c->vm_start) != size) {
+		printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
+		       __func__, c->vm_end - c->vm_start, size);
+		dump_stack();
+		size = c->vm_end - c->vm_start;
+	}
+
+	arm_vmregion_free(&coherent_head, c);
+	return 1;
+}
+
+static void *__alloc_from_contiguous(struct device *dev, size_t size,
+				     pgprot_t prot, struct page **ret_page)
+{
+	unsigned long order = get_order(size);
+	size_t count = size >> PAGE_SHIFT;
+	struct page *page;
+
+	page = dma_alloc_from_contiguous(dev, count, order);
+	if (!page)
+		return NULL;
+
+	__dma_clear_buffer(page, size);
+	__dma_remap(page, size, prot);
+
+	*ret_page = page;
+	return page_address(page);
+}
+
+static void __free_from_contiguous(struct device *dev, struct page *page,
+				   size_t size)
+{
+	__dma_remap(page, size, pgprot_kernel);
+	dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
+}
+
+#define nommu() 0
+
 #else	/* !CONFIG_MMU */
 
-#define __dma_alloc_remap(page, size, gfp, prot, c)	page_address(page)
-#define __dma_free_remap(addr, size)			do { } while (0)
+#define nommu() 1
+
+#define __alloc_remap_buffer(dev, size, gfp, prot, ret, c)	NULL
+#define __alloc_from_pool(dev, size, ret_page, c)		NULL
+#define __alloc_from_contiguous(dev, size, prot, ret)		NULL
+#define __free_from_pool(cpu_addr, size)			0
+#define __free_from_contiguous(dev, page, size)			do { } while (0)
+#define __dma_free_remap(cpu_addr, size)			do { } while (0)
 
 #endif	/* CONFIG_MMU */
 
-static void *
-__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
-	    pgprot_t prot, const void *caller)
+static void *__alloc_simple_buffer(struct device *dev, size_t size, gfp_t gfp,
+				   struct page **ret_page)
 {
 	struct page *page;
+	page = __dma_alloc_buffer(dev, size, gfp);
+	if (!page)
+		return NULL;
+
+	*ret_page = page;
+	return page_address(page);
+}
+
+
+
+static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
+			 gfp_t gfp, pgprot_t prot, const void *caller)
+{
+	u64 mask = get_coherent_dma_mask(dev);
+	struct page *page;
 	void *addr;
 
+#ifdef CONFIG_DMA_API_DEBUG
+	u64 limit = (mask + 1) & ~mask;
+	if (limit && size >= limit) {
+		dev_warn(dev, "coherent allocation too big (requested %#x mask %#llx)\n",
+			size, mask);
+		return NULL;
+	}
+#endif
+
+	if (!mask)
+		return NULL;
+
+	if (mask < 0xffffffffULL)
+		gfp |= GFP_DMA;
+
 	/*
 	 * Following is a work-around (a.k.a. hack) to prevent pages
 	 * with __GFP_COMP being passed to split_page() which cannot
@@ -345,19 +587,17 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
 	*handle = ~0;
 	size = PAGE_ALIGN(size);
 
-	page = __dma_alloc_buffer(dev, size, gfp);
-	if (!page)
-		return NULL;
-
-	if (!arch_is_coherent())
-		addr = __dma_alloc_remap(page, size, gfp, prot, caller);
+	if (arch_is_coherent() || nommu())
+		addr = __alloc_simple_buffer(dev, size, gfp, &page);
+	else if (cpu_architecture() < CPU_ARCH_ARMv6)
+		addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, caller);
+	else if (gfp & GFP_ATOMIC)
+		addr = __alloc_from_pool(dev, size, &page, caller);
 	else
-		addr = page_address(page);
+		addr = __alloc_from_contiguous(dev, size, prot, &page);
 
 	if (addr)
 		*handle = pfn_to_dma(dev, page_to_pfn(page));
-	else
-		__dma_free_buffer(page, size);
 
 	return addr;
 }
@@ -366,8 +606,8 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
  * Allocate DMA-coherent memory space and return both the kernel remapped
  * virtual and bus address for that space.
  */
-void *
-dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
+void *dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle,
+			 gfp_t gfp)
 {
 	void *memory;
 
@@ -398,25 +638,11 @@ static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
 {
 	int ret = -ENXIO;
 #ifdef CONFIG_MMU
-	unsigned long user_size, kern_size;
-	struct arm_vmregion *c;
-
-	user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
-
-	c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
-	if (c) {
-		unsigned long off = vma->vm_pgoff;
-
-		kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
-
-		if (off < kern_size &&
-		    user_size <= (kern_size - off)) {
-			ret = remap_pfn_range(vma, vma->vm_start,
-					      page_to_pfn(c->vm_pages) + off,
-					      user_size << PAGE_SHIFT,
-					      vma->vm_page_prot);
-		}
-	}
+	unsigned long pfn = dma_to_pfn(dev, dma_addr);
+	ret = remap_pfn_range(vma, vma->vm_start,
+			      pfn + vma->vm_pgoff,
+			      vma->vm_end - vma->vm_start,
+			      vma->vm_page_prot);
 #endif	/* CONFIG_MMU */
 
 	return ret;
@@ -438,23 +664,33 @@ int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
 }
 EXPORT_SYMBOL(dma_mmap_writecombine);
 
+
 /*
- * free a page as defined by the above mapping.
- * Must not be called with IRQs disabled.
+ * Free a buffer as defined by the above mapping.
  */
 void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
 {
-	WARN_ON(irqs_disabled());
+	struct page *page = pfn_to_page(dma_to_pfn(dev, handle));
 
 	if (dma_release_from_coherent(dev, get_order(size), cpu_addr))
 		return;
 
 	size = PAGE_ALIGN(size);
 
-	if (!arch_is_coherent())
+	if (arch_is_coherent() || nommu()) {
+		__dma_free_buffer(page, size);
+	} else if (cpu_architecture() < CPU_ARCH_ARMv6) {
 		__dma_free_remap(cpu_addr, size);
-
-	__dma_free_buffer(pfn_to_page(dma_to_pfn(dev, handle)), size);
+		__dma_free_buffer(page, size);
+	} else {
+		if (__free_from_pool(cpu_addr, size))
+			return;
+		/*
+		 * Non-atomic allocations cannot be freed with IRQs disabled
+		 */
+		WARN_ON(irqs_disabled());
+		__free_from_contiguous(dev, page, size);
+	}
 }
 EXPORT_SYMBOL(dma_free_coherent);
 
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 8f5813b..c21d06c 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -20,6 +20,7 @@
 #include <linux/highmem.h>
 #include <linux/gfp.h>
 #include <linux/memblock.h>
+#include <linux/dma-contiguous.h>
 
 #include <asm/mach-types.h>
 #include <asm/memblock.h>
@@ -226,6 +227,17 @@ static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
 }
 #endif
 
+void __init setup_dma_zone(struct machine_desc *mdesc)
+{
+#ifdef CONFIG_ZONE_DMA
+	if (mdesc->dma_zone_size) {
+		arm_dma_zone_size = mdesc->dma_zone_size;
+		arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
+	} else
+		arm_dma_limit = 0xffffffff;
+#endif
+}
+
 static void __init arm_bootmem_free(unsigned long min, unsigned long max_low,
 	unsigned long max_high)
 {
@@ -273,12 +285,9 @@ static void __init arm_bootmem_free(unsigned long min, unsigned long max_low,
 	 * Adjust the sizes according to any special requirements for
 	 * this machine type.
 	 */
-	if (arm_dma_zone_size) {
+	if (arm_dma_zone_size)
 		arm_adjust_dma_zone(zone_size, zhole_size,
 			arm_dma_zone_size >> PAGE_SHIFT);
-		arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
-	} else
-		arm_dma_limit = 0xffffffff;
 #endif
 
 	free_area_init_node(0, zone_size, min, zhole_size);
@@ -364,6 +373,12 @@ void __init arm_memblock_init(struct meminfo *mi, struct machine_desc *mdesc)
 	if (mdesc->reserve)
 		mdesc->reserve();
 
+	/*
+	 * reserve memory for DMA contigouos allocations,
+	 * must come from DMA area inside low memory
+	 */
+	dma_contiguous_reserve(min(arm_dma_limit, arm_lowmem_limit));
+
 	arm_memblock_steal_permitted = false;
 	memblock_allow_resize();
 	memblock_dump_all();
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index 27f4a61..93dc0c1 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -67,5 +67,8 @@ extern u32 arm_dma_limit;
 #define arm_dma_limit ((u32)~0)
 #endif
 
+extern phys_addr_t arm_lowmem_limit;
+
 void __init bootmem_init(void);
 void arm_mm_memblock_reserve(void);
+void dma_contiguous_remap(void);
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index aa78de8..e5dad60 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -288,6 +288,11 @@ static struct mem_type mem_types[] = {
 				PMD_SECT_UNCACHED | PMD_SECT_XN,
 		.domain    = DOMAIN_KERNEL,
 	},
+	[MT_MEMORY_DMA_READY] = {
+		.prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY,
+		.prot_l1   = PMD_TYPE_TABLE,
+		.domain    = DOMAIN_KERNEL,
+	},
 };
 
 const struct mem_type *get_mem_type(unsigned int type)
@@ -429,6 +434,7 @@ static void __init build_mem_type_table(void)
 	if (arch_is_coherent() && cpu_is_xsc3()) {
 		mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
 		mem_types[MT_MEMORY].prot_pte |= L_PTE_SHARED;
+		mem_types[MT_MEMORY_DMA_READY].prot_pte |= L_PTE_SHARED;
 		mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
 		mem_types[MT_MEMORY_NONCACHED].prot_pte |= L_PTE_SHARED;
 	}
@@ -460,6 +466,7 @@ static void __init build_mem_type_table(void)
 			mem_types[MT_DEVICE_CACHED].prot_pte |= L_PTE_SHARED;
 			mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
 			mem_types[MT_MEMORY].prot_pte |= L_PTE_SHARED;
+			mem_types[MT_MEMORY_DMA_READY].prot_pte |= L_PTE_SHARED;
 			mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
 			mem_types[MT_MEMORY_NONCACHED].prot_pte |= L_PTE_SHARED;
 		}
@@ -512,6 +519,7 @@ static void __init build_mem_type_table(void)
 	mem_types[MT_HIGH_VECTORS].prot_l1 |= ecc_mask;
 	mem_types[MT_MEMORY].prot_sect |= ecc_mask | cp->pmd;
 	mem_types[MT_MEMORY].prot_pte |= kern_pgprot;
+	mem_types[MT_MEMORY_DMA_READY].prot_pte |= kern_pgprot;
 	mem_types[MT_MEMORY_NONCACHED].prot_sect |= ecc_mask;
 	mem_types[MT_ROM].prot_sect |= cp->pmd;
 
@@ -596,7 +604,7 @@ static void __init alloc_init_section(pud_t *pud, unsigned long addr,
 	 * L1 entries, whereas PGDs refer to a group of L1 entries making
 	 * up one logical pointer to an L2 table.
 	 */
-	if (((addr | end | phys) & ~SECTION_MASK) == 0) {
+	if (type->prot_sect && ((addr | end | phys) & ~SECTION_MASK) == 0) {
 		pmd_t *p = pmd;
 
 #ifndef CONFIG_ARM_LPAE
@@ -814,7 +822,7 @@ static int __init early_vmalloc(char *arg)
 }
 early_param("vmalloc", early_vmalloc);
 
-static phys_addr_t lowmem_limit __initdata = 0;
+phys_addr_t arm_lowmem_limit __initdata = 0;
 
 void __init sanity_check_meminfo(void)
 {
@@ -897,8 +905,8 @@ void __init sanity_check_meminfo(void)
 			bank->size = newsize;
 		}
 #endif
-		if (!bank->highmem && bank->start + bank->size > lowmem_limit)
-			lowmem_limit = bank->start + bank->size;
+		if (!bank->highmem && bank->start + bank->size > arm_lowmem_limit)
+			arm_lowmem_limit = bank->start + bank->size;
 
 		j++;
 	}
@@ -923,8 +931,8 @@ void __init sanity_check_meminfo(void)
 	}
 #endif
 	meminfo.nr_banks = j;
-	high_memory = __va(lowmem_limit - 1) + 1;
-	memblock_set_current_limit(lowmem_limit);
+	high_memory = __va(arm_lowmem_limit - 1) + 1;
+	memblock_set_current_limit(arm_lowmem_limit);
 }
 
 static inline void prepare_page_table(void)
@@ -949,8 +957,8 @@ static inline void prepare_page_table(void)
 	 * Find the end of the first block of lowmem.
 	 */
 	end = memblock.memory.regions[0].base + memblock.memory.regions[0].size;
-	if (end >= lowmem_limit)
-		end = lowmem_limit;
+	if (end >= arm_lowmem_limit)
+		end = arm_lowmem_limit;
 
 	/*
 	 * Clear out all the kernel space mappings, except for the first
@@ -1093,8 +1101,8 @@ static void __init map_lowmem(void)
 		phys_addr_t end = start + reg->size;
 		struct map_desc map;
 
-		if (end > lowmem_limit)
-			end = lowmem_limit;
+		if (end > arm_lowmem_limit)
+			end = arm_lowmem_limit;
 		if (start >= end)
 			break;
 
@@ -1115,11 +1123,12 @@ void __init paging_init(struct machine_desc *mdesc)
 {
 	void *zero_page;
 
-	memblock_set_current_limit(lowmem_limit);
+	memblock_set_current_limit(arm_lowmem_limit);
 
 	build_mem_type_table();
 	prepare_page_table();
 	map_lowmem();
+	dma_contiguous_remap();
 	devicemaps_init(mdesc);
 	kmap_init();