8 files changed, 641 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c1601e5a8b71..669e8bb52b94 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -508,6 +508,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         Also note the kernel might malfunction if you disable
                         some critical bits.
 
+        cma=nn[MG]      [ARM,KNL]
+                        Sets the size of kernel global memory area for contiguous
+                        memory allocations. For more information, see
+                        include/linux/dma-contiguous.h
+
         cmo_free_hint=  [PPC] Format: { yes | no }
                         Specify whether pages are marked as being inactive
                         when they are freed.  This is used in CMO environments
diff --git a/arch/Kconfig b/arch/Kconfig
index 684eb5af439d..0a3ffe46e567 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -142,6 +142,9 @@ config HAVE_ARCH_TRACEHOOK
 config HAVE_DMA_ATTRS
         bool
 
+config HAVE_DMA_CONTIGUOUS
+        bool
+
 config USE_GENERIC_SMP_HELPERS
         bool
 
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 9aa618acfe97..9b21469482ae 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -192,4 +192,93 @@ config DMA_SHARED_BUFFER
           APIs extension; the file's descriptor can then be passed on to other
           driver.
 
+config CMA
+        bool "Contiguous Memory Allocator (EXPERIMENTAL)"
+        depends on HAVE_DMA_CONTIGUOUS && HAVE_MEMBLOCK && EXPERIMENTAL
+        select MIGRATION
+        help
+          This enables the Contiguous Memory Allocator which allows drivers
+          to allocate big physically-contiguous blocks of memory for use with
+          hardware components that do not support I/O map nor scatter-gather.
+
+          For more information see <include/linux/dma-contiguous.h>.
+          If unsure, say "n".
+
+if CMA
+
+config CMA_DEBUG
+        bool "CMA debug messages (DEVELOPMENT)"
+        depends on DEBUG_KERNEL
+        help
+          Turns on debug messages in CMA.  This produces KERN_DEBUG
+          messages for every CMA call as well as various messages while
+          processing calls such as dma_alloc_from_contiguous().
+          This option does not affect warning and error messages.
+
+comment "Default contiguous memory area size:"
+
+config CMA_SIZE_MBYTES
+        int "Size in Mega Bytes"
+        depends on !CMA_SIZE_SEL_PERCENTAGE
+        default 16
+        help
+          Defines the size (in MiB) of the default memory area for Contiguous
+          Memory Allocator.
+
+config CMA_SIZE_PERCENTAGE
+        int "Percentage of total memory"
+        depends on !CMA_SIZE_SEL_MBYTES
+        default 10
+        help
+          Defines the size of the default memory area for Contiguous Memory
+          Allocator as a percentage of the total memory in the system.
+
+choice
+        prompt "Selected region size"
+        default CMA_SIZE_SEL_ABSOLUTE
+
+config CMA_SIZE_SEL_MBYTES
+        bool "Use mega bytes value only"
+
+config CMA_SIZE_SEL_PERCENTAGE
+        bool "Use percentage value only"
+
+config CMA_SIZE_SEL_MIN
+        bool "Use lower value (minimum)"
+
+config CMA_SIZE_SEL_MAX
+        bool "Use higher value (maximum)"
+
+endchoice
+
+config CMA_ALIGNMENT
+        int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
+        range 4 9
+        default 8
+        help
+          DMA mapping framework by default aligns all buffers to the smallest
+          PAGE_SIZE order which is greater than or equal to the requested buffer
+          size. This works well for buffers up to a few hundreds kilobytes, but
+          for larger buffers it just a memory waste. With this parameter you can
+          specify the maximum PAGE_SIZE order for contiguous buffers. Larger
+          buffers will be aligned only to this specified order. The order is
+          expressed as a power of two multiplied by the PAGE_SIZE.
+
+          For example, if your system defaults to 4KiB pages, the order value
+          of 8 means that the buffers will be aligned up to 1MiB only.
+
+          If unsure, leave the default value "8".
+
+config 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
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index b6d1b9c4200c..5aa2d703d19f 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -6,6 +6,7 @@ obj-y			:= core.o bus.o dd.o syscore.o \
                            attribute_container.o transport_class.o \
                            topology.o
 obj-$(CONFIG_DEVTMPFS)  += devtmpfs.o
+obj-$(CONFIG_CMA) += dma-contiguous.o
 obj-y                   += power/
 obj-$(CONFIG_HAS_DMA)   += dma-mapping.o
 obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
new file mode 100644
index 000000000000..78efb0306a44
--- /dev/null
+++ b/drivers/base/dma-contiguous.c
@@ -0,0 +1,401 @@
+/*
+ * Contiguous Memory Allocator for DMA mapping framework
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Written by:
+ *      Marek Szyprowski <m.szyprowski@samsung.com>
+ *      Michal Nazarewicz <mina86@mina86.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 <asm/page.h>
+#include <asm/dma-contiguous.h>
+
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/page-isolation.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/mm_types.h>
+#include <linux/dma-contiguous.h>
+
+#ifndef SZ_1M
+#define SZ_1M (1 << 20)
+#endif
+
+struct cma {
+        unsigned long   base_pfn;
+        unsigned long   count;
+        unsigned long   *bitmap;
+};
+
+struct cma *dma_contiguous_default_area;
+
+#ifdef CONFIG_CMA_SIZE_MBYTES
+#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
+#else
+#define CMA_SIZE_MBYTES 0
+#endif
+
+/*
+ * Default global CMA area size can be defined in kernel's .config.
+ * This is usefull mainly for distro maintainers to create a kernel
+ * that works correctly for most supported systems.
+ * The size can be set in bytes or as a percentage of the total memory
+ * in the system.
+ *
+ * Users, who want to set the size of global CMA area for their system
+ * should use cma= kernel parameter.
+ */
+static const unsigned long size_bytes = CMA_SIZE_MBYTES * SZ_1M;
+static long size_cmdline = -1;
+
+static int __init early_cma(char *p)
+{
+        pr_debug("%s(%s)\n", __func__, p);
+        size_cmdline = memparse(p, &p);
+        return 0;
+}
+early_param("cma", early_cma);
+
+#ifdef CONFIG_CMA_SIZE_PERCENTAGE
+
+static unsigned long __init __maybe_unused cma_early_percent_memory(void)
+{
+        struct memblock_region *reg;
+        unsigned long total_pages = 0;
+
+        /*
+         * We cannot use memblock_phys_mem_size() here, because
+         * memblock_analyze() has not been called yet.
+         */
+        for_each_memblock(memory, reg)
+                total_pages += memblock_region_memory_end_pfn(reg) -
+                               memblock_region_memory_base_pfn(reg);
+
+        return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
+}
+
+#else
+
+static inline __maybe_unused unsigned long cma_early_percent_memory(void)
+{
+        return 0;
+}
+
+#endif
+
+/**
+ * dma_contiguous_reserve() - reserve area for contiguous memory handling
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ *
+ * 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.
+ */
+void __init dma_contiguous_reserve(phys_addr_t limit)
+{
+        unsigned long selected_size = 0;
+
+        pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
+
+        if (size_cmdline != -1) {
+                selected_size = size_cmdline;
+        } else {
+#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
+                selected_size = size_bytes;
+#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
+                selected_size = cma_early_percent_memory();
+#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
+                selected_size = min(size_bytes, cma_early_percent_memory());
+#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
+                selected_size = max(size_bytes, cma_early_percent_memory());
+#endif
+        }
+
+        if (selected_size) {
+                pr_debug("%s: reserving %ld MiB for global area\n", __func__,
+                         selected_size / SZ_1M);
+
+                dma_declare_contiguous(NULL, selected_size, 0, limit);
+        }
+};
+
+static DEFINE_MUTEX(cma_mutex);
+
+static __init int 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));
+                        if (page_zone(pfn_to_page(pfn)) != zone)
+                                return -EINVAL;
+                }
+                init_cma_reserved_pageblock(pfn_to_page(base_pfn));
+        } while (--i);
+        return 0;
+}
+
+static __init struct cma *cma_create_area(unsigned long base_pfn,
+                                     unsigned long count)
+{
+        int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
+        struct cma *cma;
+        int ret = -ENOMEM;
+
+        pr_debug("%s(base %08lx, count %lx)\n", __func__, base_pfn, count);
+
+        cma = kmalloc(sizeof *cma, GFP_KERNEL);
+        if (!cma)
+                return ERR_PTR(-ENOMEM);
+
+        cma->base_pfn = base_pfn;
+        cma->count = count;
+        cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+
+        if (!cma->bitmap)
+                goto no_mem;
+
+        ret = cma_activate_area(base_pfn, count);
+        if (ret)
+                goto error;
+
+        pr_debug("%s: returned %p\n", __func__, (void *)cma);
+        return cma;
+
+error:
+        kfree(cma->bitmap);
+no_mem:
+        kfree(cma);
+        return ERR_PTR(ret);
+}
+
+static struct cma_reserved {
+        phys_addr_t start;
+        unsigned long size;
+        struct device *dev;
+} cma_reserved[MAX_CMA_AREAS] __initdata;
+static unsigned cma_reserved_count __initdata;
+
+static int __init cma_init_reserved_areas(void)
+{
+        struct cma_reserved *r = cma_reserved;
+        unsigned i = cma_reserved_count;
+
+        pr_debug("%s()\n", __func__);
+
+        for (; i; --i, ++r) {
+                struct cma *cma;
+                cma = cma_create_area(PFN_DOWN(r->start),
+                                      r->size >> PAGE_SHIFT);
+                if (!IS_ERR(cma))
+                        dev_set_cma_area(r->dev, cma);
+        }
+        return 0;
+}
+core_initcall(cma_init_reserved_areas);
+
+/**
+ * dma_declare_contiguous() - reserve area for contiguous memory handling
+ *                            for particular device
+ * @dev:   Pointer to device structure.
+ * @size:  Size of the reserved memory.
+ * @base:  Start address of the reserved memory (optional, 0 for any).
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ *
+ * This function reserves memory for specified device. It should be
+ * called by board specific code when early allocator (memblock or bootmem)
+ * is still activate.
+ */
+int __init dma_declare_contiguous(struct device *dev, unsigned long size,
+                                  phys_addr_t base, phys_addr_t limit)
+{
+        struct cma_reserved *r = &cma_reserved[cma_reserved_count];
+        unsigned long alignment;
+
+        pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
+                 (unsigned long)size, (unsigned long)base,
+                 (unsigned long)limit);
+
+        /* Sanity checks */
+        if (cma_reserved_count == ARRAY_SIZE(cma_reserved)) {
+                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, pageblock_order);
+        base = ALIGN(base, alignment);
+        size = ALIGN(size, alignment);
+        limit &= ~(alignment - 1);
+
+        /* Reserve memory */
+        if (base) {
+                if (memblock_is_region_reserved(base, size) ||
+                    memblock_reserve(base, size) < 0) {
+                        base = -EBUSY;
+                        goto err;
+                }
+        } else {
+                /*
+                 * Use __memblock_alloc_base() since
+                 * memblock_alloc_base() panic()s.
+                 */
+                phys_addr_t addr = __memblock_alloc_base(size, alignment, limit);
+                if (!addr) {
+                        base = -ENOMEM;
+                        goto err;
+                } else if (addr + size > ~(unsigned long)0) {
+                        memblock_free(addr, size);
+                        base = -EINVAL;
+                        goto err;
+                } else {
+                        base = addr;
+                }
+        }
+
+        /*
+         * Each reserved area must be initialised later, when more kernel
+         * subsystems (like slab allocator) are available.
+         */
+        r->start = base;
+        r->size = size;
+        r->dev = dev;
+        cma_reserved_count++;
+        pr_info("CMA: reserved %ld MiB at %08lx\n", size / SZ_1M,
+                (unsigned long)base);
+
+        /* Architecture specific contiguous memory fixup. */
+        dma_contiguous_early_fixup(base, size);
+        return 0;
+err:
+        pr_err("CMA: failed to reserve %ld MiB\n", size / SZ_1M);
+        return base;
+}
+
+/**
+ * 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 get_dev_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);
+        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;
+
+        mutex_lock(&cma_mutex);
+
+        for (;;) {
+                pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
+                                                    start, count, mask);
+                if (pageno >= cma->count) {
+                        ret = -ENOMEM;
+                        goto error;
+                }
+
+                pfn = cma->base_pfn + pageno;
+                ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
+                if (ret == 0) {
+                        bitmap_set(cma->bitmap, pageno, count);
+                        break;
+                } else if (ret != -EBUSY) {
+                        goto error;
+                }
+                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(&cma_mutex);
+
+        pr_debug("%s(): returned %p\n", __func__, pfn_to_page(pfn));
+        return pfn_to_page(pfn);
+error:
+        mutex_unlock(&cma_mutex);
+        return NULL;
+}
+
+/**
+ * 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);
+
+        mutex_lock(&cma_mutex);
+        bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
+        free_contig_range(pfn, count);
+        mutex_unlock(&cma_mutex);
+
+        return true;
+}
diff --git a/include/asm-generic/dma-contiguous.h b/include/asm-generic/dma-contiguous.h
new file mode 100644
index 000000000000..c544356b374b
--- /dev/null
+++ b/include/asm-generic/dma-contiguous.h
@@ -0,0 +1,28 @@
+#ifndef ASM_DMA_CONTIGUOUS_H
+#define ASM_DMA_CONTIGUOUS_H
+
+#ifdef __KERNEL__
+#ifdef CONFIG_CMA
+
+#include <linux/device.h>
+#include <linux/dma-contiguous.h>
+
+static inline struct cma *dev_get_cma_area(struct device *dev)
+{
+        if (dev && dev->cma_area)
+                return dev->cma_area;
+        return dma_contiguous_default_area;
+}
+
+static inline void dev_set_cma_area(struct device *dev, struct cma *cma)
+{
+        if (dev)
+                dev->cma_area = cma;
+        if (!dev || !dma_contiguous_default_area)
+                dma_contiguous_default_area = cma;
+}
+
+#endif
+#endif
+
+#endif
diff --git a/include/linux/device.h b/include/linux/device.h
index 5ad17cccdd71..e3399290436e 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -661,6 +661,10 @@ struct device {
 
         struct dma_coherent_mem *dma_mem; /* internal for coherent mem
                                              override */
+#ifdef CONFIG_CMA
+        struct cma *cma_area;           /* contiguous memory area for dma
+                                           allocations */
+#endif
         /* arch specific additions */
         struct dev_archdata     archdata;
 
diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
new file mode 100644
index 000000000000..2f303e4b7ed3
--- /dev/null
+++ b/include/linux/dma-contiguous.h
@@ -0,0 +1,110 @@
+#ifndef __LINUX_CMA_H
+#define __LINUX_CMA_H
+
+/*
+ * Contiguous Memory Allocator for DMA mapping framework
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Written by:
+ *      Marek Szyprowski <m.szyprowski@samsung.com>
+ *      Michal Nazarewicz <mina86@mina86.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.
+ */
+
+/*
+ * Contiguous Memory Allocator
+ *
+ *   The Contiguous Memory Allocator (CMA) makes it possible to
+ *   allocate big contiguous chunks of memory after the system has
+ *   booted.
+ *
+ * Why is it needed?
+ *
+ *   Various devices on embedded systems have no scatter-getter and/or
+ *   IO map support and require contiguous blocks of memory to
+ *   operate.  They include devices such as cameras, hardware video
+ *   coders, etc.
+ *
+ *   Such devices often require big memory buffers (a full HD frame
+ *   is, for instance, more then 2 mega pixels large, i.e. more than 6
+ *   MB of memory), which makes mechanisms such as kmalloc() or
+ *   alloc_page() ineffective.
+ *
+ *   At the same time, a solution where a big memory region is
+ *   reserved for a device is suboptimal since often more memory is
+ *   reserved then strictly required and, moreover, the memory is
+ *   inaccessible to page system even if device drivers don't use it.
+ *
+ *   CMA tries to solve this issue by operating on memory regions
+ *   where only movable pages can be allocated from.  This way, kernel
+ *   can use the memory for pagecache and when device driver requests
+ *   it, allocated pages can be migrated.
+ *
+ * Driver usage
+ *
+ *   CMA should not be used by the device drivers directly. It is
+ *   only a helper framework for dma-mapping subsystem.
+ *
+ *   For more information, see kernel-docs in drivers/base/dma-contiguous.c
+ */
+
+#ifdef __KERNEL__
+
+struct cma;
+struct page;
+struct device;
+
+#ifdef CONFIG_CMA
+
+/*
+ * 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)
+
+extern struct cma *dma_contiguous_default_area;
+
+void dma_contiguous_reserve(phys_addr_t addr_limit);
+int dma_declare_contiguous(struct device *dev, unsigned long size,
+                           phys_addr_t base, phys_addr_t limit);
+
+struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+                                       unsigned int order);
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+                                 int count);
+
+#else
+
+#define MAX_CMA_AREAS   (0)
+
+static inline void dma_contiguous_reserve(phys_addr_t limit) { }
+
+static inline
+int dma_declare_contiguous(struct device *dev, unsigned long size,
+                           phys_addr_t base, phys_addr_t limit)
+{
+        return -ENOSYS;
+}
+
+static inline
+struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+                                       unsigned int order)
+{
+        return NULL;
+}
+
+static inline
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+                                 int count)
+{
+        return false;
+}
+
+#endif
+
+#endif
+
+#endif