new file mode 100644
@@ -0,0 +1,219 @@
+#ifndef __LINUX_CMA_H
+#define __LINUX_CMA_H
+
+/*
+ * Contiguous Memory Allocator
+ * Copyright (c) 2010 by Samsung Electronics.
+ * Written by Michal Nazarewicz (m.nazarewicz@samsung.com)
+ */
+
+/*
+ * Contiguous Memory Allocator
+ *
+ * The Contiguous Memory Allocator (CMA) makes it possible for
+ * device drivers to allocate big contiguous chunks of memory after
+ * the system has booted.
+ *
+ * It requires some machine- and/or platform-specific initialisation
+ * code which prepares memory ranges to be used with CMA and later,
+ * device drivers can allocate memory from those ranges.
+ *
+ * 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
+ *
+ * For device driver to use CMA it needs to have a pointer to a CMA
+ * context represented by a struct cma (which is an opaque data
+ * type).
+ *
+ * Once such pointer is obtained, device driver may allocate
+ * contiguous memory chunk using the following function:
+ *
+ * cm_alloc()
+ *
+ * This function returns a pointer to struct cm (another opaque data
+ * type) which represent a contiguous memory chunk. This pointer
+ * may be used with the following functions:
+ *
+ * cm_free() -- frees allocated contiguous memory
+ * cm_pin() -- pins memory
+ * cm_unpin() -- unpins memory
+ * cm_vmap() -- maps memory in kernel space
+ * cm_vunmap() -- unmaps memory from kernel space
+ *
+ * See the respective functions for more information.
+ *
+ * Platform/machine integration
+ *
+ * For device drivers to be able to use CMA platform or machine
+ * initialisation code must create a CMA context and pass it to
+ * device drivers. The latter may be done by a global variable or
+ * a platform/machine specific function. For the former CMA
+ * provides the following functions:
+ *
+ * cma_reserve()
+ * cma_create()
+ *
+ * The cma_reserve() function must be called when memblock is still
+ * operational and reserving memory with it is still possible. On
+ * ARM platform the "reserve" machine callback is a perfect place to
+ * call it.
+ *
+ * The last function creates a CMA context on a range of previously
+ * initialised memory addresses. Because it uses kmalloc() it needs
+ * to be called after SLAB is initialised.
+ */
+
+/***************************** Kernel level API *****************************/
+
+#if defined __KERNEL__ && defined CONFIG_CMA
+
+/* CMA context */
+struct cma;
+/* Contiguous Memory chunk */
+struct cm;
+
+/**
+ * cma_reserve() - reserves memory.
+ * @start: start address of the memory range in bytes hint; if unsure
+ * pass zero.
+ * @size: size of the memory to reserve in bytes.
+ * @alignment: desired alignment in bytes (must be power of two or zero).
+ *
+ * It will use memblock to allocate memory. @start and @size will be
+ * aligned to PAGE_SIZE.
+ *
+ * Returns reserved's area physical address or value that yields true
+ * when checked with IS_ERR_VALUE().
+ */
+unsigned long cma_reserve(unsigned long start, unsigned long size,
+ unsigned long alignment);
+
+/**
+ * cma_create() - creates a CMA context.
+ * @start: start address of the context in bytes.
+ * @size: size of the context in bytes.
+ * @min_alignment: minimal desired alignment or zero.
+ * @private: whether to create private context.
+ *
+ * The range must be page aligned. Different contexts cannot overlap.
+ *
+ * Unless @private is true the memory range must lay in ZONE_MOVABLE.
+ * If @private is true no underlaying memory checking is done and
+ * during allocation no pages migration will be performed - it is
+ * assumed that the memory is reserved and only CMA manages it.
+ *
+ * @start and @size must be page and @min_alignment alignment.
+ * @min_alignment specifies the minimal alignment that user will be
+ * able to request through cm_alloc() function. In most cases one
+ * will probably pass zero as @min_alignment but if the CMA context
+ * will be used only for, say, 1 MiB blocks passing 1 << 20 as
+ * @min_alignment may increase performance and reduce memory usage
+ * slightly.
+ *
+ * Because this function uses kmalloc() it must be called after SLAB
+ * is initialised. This in particular means that it cannot be called
+ * just after cma_reserve() since the former needs to be run way
+ * earlier.
+ *
+ * Returns pointer to CMA context or a pointer-error on error.
+ */
+struct cma *cma_create(unsigned long start, unsigned long size,
+ unsigned long min_alignment, _Bool private);
+
+/**
+ * cma_destroy() - destroys CMA context.
+ * @cma: context to destroy.
+ */
+void cma_destroy(struct cma *cma);
+
+/**
+ * cm_alloc() - allocates contiguous memory.
+ * @cma: CMA context to use.
+ * @size: desired chunk size in bytes (must be non-zero).
+ * @alignent: desired minimal alignment in bytes (must be power of two
+ * or zero).
+ *
+ * Returns pointer to structure representing contiguous memory or
+ * a pointer-error on error.
+ */
+struct cm *cm_alloc(struct cma *cma, unsigned long size,
+ unsigned long alignment);
+
+/**
+ * cm_free() - frees contiguous memory.
+ * @cm: contiguous memory to free.
+ *
+ * The contiguous memory must be not be pinned (see cma_pin()) and
+ * must not be mapped to kernel space (cma_vmap()).
+ */
+void cm_free(struct cm *cm);
+
+/**
+ * cm_pin() - pins contiguous memory.
+ * @cm: contiguous memory to pin.
+ *
+ * Pinning is required to obtain contiguous memory's physical address.
+ * While memory is pinned the memory will remain valid it may change
+ * if memory is unpinned and then pinned again. This facility is
+ * provided so that memory defragmentation can be implemented inside
+ * CMA.
+ *
+ * Each call to cm_pin() must be accompanied by call to cm_unpin() and
+ * the calls may be nested.
+ *
+ * Returns chunk's physical address or a value that yields true when
+ * tested with IS_ERR_VALUE().
+ */
+unsigned long cm_pin(struct cm *cm);
+
+/**
+ * cm_unpin() - unpins contiguous memory.
+ * @cm: contiguous memory to unpin.
+ *
+ * See cm_pin().
+ */
+void cm_unpin(struct cm *cm);
+
+/**
+ * cm_vmap() - maps memory to kernel space (or returns existing mapping).
+ * @cm: contiguous memory to map.
+ *
+ * Each call to cm_vmap() must be accompanied with call to cm_vunmap()
+ * and the calls may be nested.
+ *
+ * Returns kernel virtual address or a pointer-error.
+ */
+void *cm_vmap(struct cm *cm);
+
+/**
+ * cm_vunmap() - unmpas memory from kernel space.
+ * @cm: contiguous memory to unmap.
+ *
+ * See cm_vmap().
+ */
+void cm_vunmap(struct cm *cm);
+
+#endif
+
+#endif
@@ -340,6 +340,34 @@ choice
benefit.
endchoice
+config CMA
+ bool "Contiguous Memory Allocator framework"
+ # Currently there is only one allocator so force it on
+ select MIGRATION
+ select GENERIC_ALLOCATOR
+ help
+ This enables the Contiguous Memory Allocator framework 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.
+
+ If you select this option you will also have to select at least
+ one allocator algorithm below.
+
+ To make use of CMA you need to specify the regions and
+ driver->region mapping on command line when booting the kernel.
+
+ For more information see <include/linux/cma.h>. If unsure, say "n".
+
+config CMA_DEBUG
+ bool "CMA debug messages (DEVELOPEMENT)"
+ depends on CMA
+ 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 cma_alloc(). This option does not
+ affect warning and error messages.
+
#
# UP and nommu archs use km based percpu allocator
#
@@ -49,3 +49,4 @@ obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o
obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o
obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o
obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o
+obj-$(CONFIG_CMA) += cma.o
new file mode 100644
@@ -0,0 +1,330 @@
+/*
+ * Contiguous Memory Allocator framework
+ * Copyright (c) 2010 by Samsung Electronics.
+ * Written by Michal Nazarewicz (m.nazarewicz@samsung.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.
+ */
+
+/*
+ * See include/linux/cma.h for details.
+ */
+
+#define pr_fmt(fmt) "cma: " fmt
+
+#ifdef CONFIG_CMA_DEBUG
+# define DEBUG
+#endif
+
+#include <linux/cma.h>
+
+#ifndef CONFIG_NO_BOOTMEM
+# include <linux/bootmem.h>
+#endif
+#ifdef CONFIG_HAVE_MEMBLOCK
+# include <linux/memblock.h>
+#endif
+
+#include <linux/err.h>
+#include <linux/genalloc.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/page-isolation.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+
+#include <asm/page.h>
+
+#include "internal.h"
+
+/* XXX Revisit */
+#ifdef phys_to_pfn
+/* nothing to do */
+#elif defined __phys_to_pfn
+# define phys_to_pfn __phys_to_pfn
+#else
+# warning correct phys_to_pfn implementation needed
+static unsigned long phys_to_pfn(phys_addr_t phys)
+{
+ return virt_to_pfn(phys_to_virt(phys));
+}
+#endif
+
+
+/************************* Initialise CMA *************************/
+
+unsigned long cma_reserve(unsigned long start, unsigned long size,
+ unsigned long alignment)
+{
+ pr_debug("%s(%p+%p/%p)\n", __func__, (void *)start, (void *)size,
+ (void *)alignment);
+
+ /* Sanity checks */
+ if (!size || (alignment & (alignment - 1)))
+ return (unsigned long)-EINVAL;
+
+ /* Sanitise input arguments */
+ start = PAGE_ALIGN(start);
+ size = PAGE_ALIGN(size);
+ if (alignment < PAGE_SIZE)
+ alignment = PAGE_SIZE;
+
+ /* Reserve memory */
+ if (start) {
+ if (memblock_is_region_reserved(start, size) ||
+ memblock_reserve(start, size) < 0)
+ return (unsigned long)-EBUSY;
+ } else {
+ /*
+ * Use __memblock_alloc_base() since
+ * memblock_alloc_base() panic()s.
+ */
+ u64 addr = __memblock_alloc_base(size, alignment, 0);
+ if (!addr) {
+ return (unsigned long)-ENOMEM;
+ } else if (addr + size > ~(unsigned long)0) {
+ memblock_free(addr, size);
+ return (unsigned long)-EOVERFLOW;
+ } else {
+ start = addr;
+ }
+ }
+
+ return start;
+}
+
+
+/************************** CMA context ***************************/
+
+struct cma {
+ bool migrate;
+ struct gen_pool *pool;
+};
+
+static int __cma_check_range(unsigned long start, unsigned long size)
+{
+ unsigned long pfn, count;
+ struct page *page;
+ struct zone *zone;
+
+ start = phys_to_pfn(start);
+ if (WARN_ON(!pfn_valid(start)))
+ return -EINVAL;
+
+ if (WARN_ON(page_zonenum(pfn_to_page(start)) != ZONE_MOVABLE))
+ return -EINVAL;
+
+ /* First check if all pages are valid and in the same zone */
+ zone = page_zone(pfn_to_page(start));
+ count = size >> PAGE_SHIFT;
+ pfn = start;
+ while (++pfn, --count) {
+ if (WARN_ON(!pfn_valid(pfn)) ||
+ WARN_ON(page_zone(pfn_to_page(pfn)) != zone))
+ return -EINVAL;
+ }
+
+ /* Now check migratetype of their pageblocks. */
+ start = start & ~(pageblock_nr_pages - 1);
+ pfn = ALIGN(pfn, pageblock_nr_pages);
+ page = pfn_to_page(start);
+ count = (pfn - start) >> PAGE_SHIFT;
+ do {
+ if (WARN_ON(get_pageblock_migratetype(page) != MIGRATE_MOVABLE))
+ return -EINVAL;
+ page += pageblock_nr_pages;
+ } while (--count);
+
+ return 0;
+}
+
+struct cma *cma_create(unsigned long start, unsigned long size,
+ unsigned long min_alignment, bool private)
+{
+ struct gen_pool *pool;
+ struct cma *cma;
+ int ret;
+
+ pr_debug("%s(%p+%p)\n", __func__, (void *)start, (void *)size);
+
+ if (!size)
+ return ERR_PTR(-EINVAL);
+ if (min_alignment & (min_alignment - 1))
+ return ERR_PTR(-EINVAL);
+ if (min_alignment < PAGE_SIZE)
+ min_alignment = PAGE_SIZE;
+ if ((start | size) & (min_alignment - 1))
+ return ERR_PTR(-EINVAL);
+ if (start + size < start)
+ return ERR_PTR(-EOVERFLOW);
+
+ if (!private) {
+ ret = __cma_check_range(start, size);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ }
+
+ cma = kmalloc(sizeof *cma, GFP_KERNEL);
+ if (!cma)
+ return ERR_PTR(-ENOMEM);
+
+ pool = gen_pool_create(ffs(min_alignment) - 1, -1);
+ if (!pool) {
+ ret = -ENOMEM;
+ goto error1;
+ }
+
+ ret = gen_pool_add(pool, start, size, -1);
+ if (unlikely(ret))
+ goto error2;
+
+ cma->migrate = !private;
+ cma->pool = pool;
+
+ pr_debug("%s: returning <%p>\n", __func__, (void *)cma);
+ return cma;
+
+error2:
+ gen_pool_destroy(pool);
+error1:
+ kfree(cma);
+ return ERR_PTR(ret);
+}
+
+void cma_destroy(struct cma *cma)
+{
+ pr_debug("%s(<%p>)\n", __func__, (void *)cma);
+ gen_pool_destroy(cma->pool);
+}
+
+
+/************************* Allocate and free *************************/
+
+struct cm {
+ struct cma *cma;
+ unsigned long phys, size;
+ atomic_t pinned, mapped;
+};
+
+/* Protects cm_alloc(), cm_free() as well as gen_pools of each cm. */
+static DEFINE_MUTEX(cma_mutex);
+
+struct cm *cm_alloc(struct cma *cma, unsigned long size,
+ unsigned long alignment)
+{
+ unsigned long start;
+ int ret = -ENOMEM;
+ struct cm *cm;
+
+ pr_debug("%s(<%p>, %p/%p)\n", __func__, (void *)cma,
+ (void *)size, (void *)alignment);
+
+ if (!size || (alignment & (alignment - 1)))
+ return ERR_PTR(-EINVAL);
+ size = PAGE_ALIGN(size);
+
+ cm = kmalloc(sizeof *cm, GFP_KERNEL);
+ if (!cm)
+ return ERR_PTR(-ENOMEM);
+
+ mutex_lock(&cma_mutex);
+
+ start = gen_pool_alloc_aligned(cma->pool, size,
+ alignment ? ffs(alignment) - 1 : 0);
+ if (!start)
+ goto error1;
+
+ if (cma->migrate) {
+ unsigned long pfn = phys_to_pfn(start);
+ ret = alloc_contig_range(pfn, pfn + (size >> PAGE_SHIFT), 0);
+ if (ret) {
+ pr_info("cma allocation failed\n");
+ goto error2;
+ }
+ }
+
+ mutex_unlock(&cma_mutex);
+
+ cm->cma = cma;
+ cm->phys = start;
+ cm->size = size;
+ atomic_set(&cm->pinned, 0);
+ atomic_set(&cm->mapped, 0);
+
+ pr_debug("%s(): returning [%p]\n", __func__, (void *)cm);
+ return cm;
+
+error2:
+ gen_pool_free(cma->pool, start, size);
+error1:
+ mutex_unlock(&cma_mutex);
+ kfree(cm);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(cm_alloc);
+
+void cm_free(struct cm *cm)
+{
+ pr_debug("%s([%p])\n", __func__, (void *)cm);
+
+ if (WARN_ON(atomic_read(&cm->pinned) || atomic_read(&cm->mapped)))
+ return;
+
+ mutex_lock(&cma_mutex);
+
+ gen_pool_free(cm->cma->pool, cm->phys, cm->size);
+ if (cm->cma->migrate)
+ free_contig_pages(phys_to_page(cm->phys),
+ cm->size >> PAGE_SHIFT);
+
+ mutex_unlock(&cma_mutex);
+
+ kfree(cm);
+}
+EXPORT_SYMBOL_GPL(cm_free);
+
+
+/************************* Mapping and addresses *************************/
+
+/*
+ * Currently no-operations but keep reference counters for error
+ * checking.
+ */
+
+unsigned long cm_pin(struct cm *cm)
+{
+ pr_debug("%s([%p])\n", __func__, (void *)cm);
+ atomic_inc(&cm->pinned);
+ return cm->phys;
+}
+EXPORT_SYMBOL_GPL(cm_pin);
+
+void cm_unpin(struct cm *cm)
+{
+ pr_debug("%s([%p])\n", __func__, (void *)cm);
+ WARN_ON(!atomic_add_unless(&cm->pinned, -1, 0));
+}
+EXPORT_SYMBOL_GPL(cm_unpin);
+
+void *cm_vmap(struct cm *cm)
+{
+ pr_debug("%s([%p])\n", __func__, (void *)cm);
+ atomic_inc(&cm->mapped);
+ /*
+ * XXX We should probably do something more clever in the
+ * future. The memory might be highmem after all.
+ */
+ return phys_to_virt(cm->phys);
+}
+EXPORT_SYMBOL_GPL(cm_vmap);
+
+void cm_vunmap(struct cm *cm)
+{
+ pr_debug("%s([%p])\n", __func__, (void *)cm);
+ WARN_ON(!atomic_add_unless(&cm->mapped, -1, 0));
+}
+EXPORT_SYMBOL_GPL(cm_vunmap);
@@ -5713,7 +5713,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
return -EINVAL;
_start = start & (~0UL << ret);
- _end = alloc_contig_freed_pages(_start, end, flag);
+ _end = alloc_contig_freed_pages(_start, end, flags);
/* Free head and tail (if any) */
if (start != _start)