ARM: integrate CMA with DMA-mapping subsystem
authorMarek Szyprowski <m.szyprowski@samsung.com>
Thu, 29 Dec 2011 12:09:51 +0000 (13:09 +0100)
committerGrazvydas Ignotas <notasas@gmail.com>
Tue, 26 Feb 2013 17:51:18 +0000 (19:51 +0200)
This patch adds support for CMA to dma-mapping subsystem for ARM
architecture. By default a global CMA area is used, but specific devices
are allowed to have their private memory areas if required (they can be
created with dma_declare_contiguous() function during board
initialisation).

Contiguous memory areas reserved for DMA are remapped with 2-level page
tables on boot. Once a buffer is requested, a low memory kernel mapping
is updated to to match requested memory access type.

GFP_ATOMIC allocations are performed from special pool which is created
early during boot. This way remapping page attributes is not needed on
allocation time.

CMA has been enabled unconditionally for ARMv6+ systems.

[notasas@gmail.com: backport to 3.2]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
Tested-by: Barry Song <Baohua.Song@csr.com>
Conflicts:

arch/arm/Kconfig
arch/arm/kernel/setup.c
arch/arm/mm/dma-mapping.c
arch/arm/mm/init.c

Documentation/kernel-parameters.txt
arch/arm/Kconfig
arch/arm/include/asm/dma-contiguous.h [new file with mode: 0644]
arch/arm/include/asm/mach/map.h
arch/arm/kernel/setup.c
arch/arm/mm/dma-mapping.c
arch/arm/mm/init.c
arch/arm/mm/mm.h
arch/arm/mm/mmu.c

index 4f12cda..45182ac 100644 (file)
@@ -515,6 +515,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        a hypervisor.
                        Default: yes
 
+       coherent_pool=nn[KMG]   [ARM,KNL]
+                       Sets the size of memory pool for coherent, atomic dma
+                       allocations if Contiguous Memory Allocator (CMA) is used.
+
        code_bytes      [X86] How many bytes of object code to print
                        in an oops report.
                        Range: 0 - 8192
index 030d767..17dbe3f 100644 (file)
@@ -5,6 +5,8 @@ config ARM
        select HAVE_DMA_API_DEBUG
        select HAVE_IDE if PCI || ISA || PCMCIA
        select HAVE_DMA_ATTRS
+       select HAVE_DMA_CONTIGUOUS if (CPU_V6 || CPU_V6K || CPU_V7)
+       select CMA if (CPU_V6 || CPU_V6K || CPU_V7)
        select HAVE_MEMBLOCK
        select RTC_LIB
        select SYS_SUPPORTS_APM_EMULATION
diff --git a/arch/arm/include/asm/dma-contiguous.h b/arch/arm/include/asm/dma-contiguous.h
new file mode 100644 (file)
index 0000000..3ed37b4
--- /dev/null
@@ -0,0 +1,15 @@
+#ifndef ASMARM_DMA_CONTIGUOUS_H
+#define ASMARM_DMA_CONTIGUOUS_H
+
+#ifdef __KERNEL__
+#ifdef CONFIG_CMA
+
+#include <linux/types.h>
+#include <asm-generic/dma-contiguous.h>
+
+void dma_contiguous_early_fixup(phys_addr_t base, unsigned long size);
+
+#endif
+#endif
+
+#endif
index b36f365..a6efcdd 100644 (file)
@@ -30,6 +30,7 @@ struct map_desc {
 #define MT_MEMORY_DTCM         12
 #define MT_MEMORY_ITCM         13
 #define MT_MEMORY_SO           14
+#define MT_MEMORY_DMA_READY    15
 
 #ifdef CONFIG_MMU
 extern void iotable_init(struct map_desc *, int);
index c98ff98..e482ef9 100644 (file)
@@ -79,6 +79,7 @@ __setup("fpe=", fpe_setup);
 extern void paging_init(struct machine_desc *desc);
 extern void sanity_check_meminfo(void);
 extern void reboot_setup(char *str);
+extern void setup_dma_zone(struct machine_desc *desc);
 
 unsigned int processor_id;
 EXPORT_SYMBOL(processor_id);
@@ -909,12 +910,8 @@ void __init setup_arch(char **cmdline_p)
        machine_desc = mdesc;
        machine_name = mdesc->name;
 
-#ifdef CONFIG_ZONE_DMA
-       if (mdesc->dma_zone_size) {
-               extern unsigned long arm_dma_zone_size;
-               arm_dma_zone_size = mdesc->dma_zone_size;
-       }
-#endif
+       setup_dma_zone(mdesc);
+
        if (mdesc->soft_reboot)
                reboot_setup("s");
 
index ecdb9cf..8665fd2 100644 (file)
@@ -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 <linux/iommu.h>
 #include <linux/vmalloc.h>
@@ -29,6 +31,9 @@
 #include <asm/sizes.h>
 #include <asm/mach/arch.h>
 #include <asm/dma-iommu.h>
+#include <asm/mach/map.h>
+#include <asm/system.h>
+#include <asm/dma-contiguous.h>
 
 #include "mm.h"
 
@@ -181,22 +186,6 @@ 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;
-       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)
@@ -279,6 +268,9 @@ 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__);
@@ -319,9 +311,101 @@ 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)
@@ -428,6 +512,122 @@ 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);
+}
+
 static inline pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot)
 {
        prot = dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs) ?
@@ -436,21 +636,57 @@ static inline pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot)
        return prot;
 }
 
+#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 __get_dma_pgprot(attrs, prot)  __pgprot(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
@@ -463,19 +699,17 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
        *handle = DMA_ERROR_CODE;
        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;
 }
@@ -506,54 +740,47 @@ int arm_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;
-
-       vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
+       unsigned long pfn = dma_to_pfn(dev, dma_addr);
 
        if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
                return ret;
 
-       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;
-               struct page *pages = c->priv;
-
-               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(pages) + off,
-                                             user_size << PAGE_SHIFT,
-                                             vma->vm_page_prot);
-               }
-       }
+       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;
 }
 
 /*
- * 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 arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
                  dma_addr_t handle, struct dma_attrs *attrs)
 {
-       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);
+       }
 }
 
 static void dma_cache_maint_page(struct page *page, unsigned long offset,
index 786addd..1b8bfd7 100644 (file)
@@ -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/prom.h>
@@ -225,6 +226,17 @@ 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)
 {
@@ -272,12 +284,9 @@ 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);
@@ -349,6 +358,12 @@ 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));
+
        memblock_analyze();
        memblock_dump_all();
 }
index ad7cce3..fa95d9b 100644 (file)
@@ -29,5 +29,8 @@ 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);
index cabbc23..39e8f4e 100644 (file)
@@ -285,6 +285,11 @@ 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)
@@ -441,6 +446,7 @@ 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;
        }
@@ -472,6 +478,7 @@ 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;
                }
@@ -523,6 +530,7 @@ 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;
 
@@ -614,7 +622,7 @@ 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
@@ -816,7 +824,7 @@ 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)
 {
@@ -899,8 +907,8 @@ 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++;
        }
@@ -925,8 +933,8 @@ 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)
@@ -951,8 +959,8 @@ 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
@@ -1092,8 +1100,8 @@ 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;
 
@@ -1114,11 +1122,12 @@ 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();