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
--- /dev/null
+/*
+ * 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;
+}
--- /dev/null
+#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
projects / GitHub / LineageOS / android_kernel_samsung_universal7580.git / commitdiff