blob: ed914806babbc71c6863cef3c21ca9d3288231b2 [file] [log] [blame]
/*
* 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.
*
* The Linux Foundation chooses to take subject only to the GPLv2 license
* terms, and distributes only under these terms.
*/
#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/of.h>
#include <linux/of_fdt.h>
#include <linux/of_platform.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>
#include <trace/events/kmem.h>
#ifndef SZ_1M
#define SZ_1M (1 << 20)
#endif
struct cma {
unsigned long base_pfn;
unsigned long count;
unsigned long *bitmap;
};
static DEFINE_MUTEX(cma_mutex);
struct cma *dma_contiguous_def_area;
phys_addr_t dma_contiguous_def_base;
static struct cma_area {
phys_addr_t base;
unsigned long size;
struct cma *cma;
const char *name;
} cma_areas[MAX_CMA_AREAS];
static unsigned cma_area_count;
static struct cma_map {
phys_addr_t base;
struct device *dev;
} cma_maps[MAX_CMA_AREAS] __initdata;
static unsigned cma_map_count __initdata;
static struct cma *cma_get_area(phys_addr_t base)
{
int i;
for (i = 0; i < cma_area_count; i++)
if (cma_areas[i].base == base)
return cma_areas[i].cma;
return NULL;
}
static struct cma *cma_get_area_by_name(const char *name)
{
int i;
if (!name)
return NULL;
for (i = 0; i < cma_area_count; i++)
if (cma_areas[i].name && strcmp(cma_areas[i].name, name) == 0)
return cma_areas[i].cma;
return NULL;
}
#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 phys_addr_t size_bytes = CMA_SIZE_MBYTES * SZ_1M;
static phys_addr_t 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 phys_addr_t __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 phys_addr_t cma_early_percent_memory(void)
{
return 0;
}
#endif
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);
}
/*****************************************************************************/
#ifdef CONFIG_OF
int __init cma_fdt_scan(unsigned long node, const char *uname,
int depth, void *data)
{
phys_addr_t base, size;
unsigned long len;
__be32 *prop;
char *name;
if (!of_get_flat_dt_prop(node, "linux,contiguous-region", NULL))
return 0;
prop = of_get_flat_dt_prop(node, "reg", &len);
if (!prop || (len != 2 * sizeof(unsigned long)))
return 0;
base = be32_to_cpu(prop[0]);
size = be32_to_cpu(prop[1]);
name = of_get_flat_dt_prop(node, "label", NULL);
pr_info("Found %s, memory base %lx, size %ld MiB\n", uname,
(unsigned long)base, (unsigned long)size / SZ_1M);
dma_contiguous_reserve_area(size, &base, 0, name);
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. It reserves contiguous areas for global, device independent
* allocations and (optionally) all areas defined in device tree structures.
*/
void __init dma_contiguous_reserve(phys_addr_t limit)
{
phys_addr_t sel_size = 0;
pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
if (size_cmdline != -1) {
sel_size = size_cmdline;
} else {
#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
sel_size = size_bytes;
#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
sel_size = cma_early_percent_memory();
#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
sel_size = min(size_bytes, cma_early_percent_memory());
#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
sel_size = max(size_bytes, cma_early_percent_memory());
#endif
}
if (sel_size) {
phys_addr_t base = 0;
pr_debug("%s: reserving %ld MiB for global area\n", __func__,
(unsigned long)sel_size / SZ_1M);
if (dma_contiguous_reserve_area(sel_size, &base, limit, NULL)
== 0)
dma_contiguous_def_base = base;
}
#ifdef CONFIG_OF
of_scan_flat_dt(cma_fdt_scan, NULL);
#endif
};
/**
* dma_contiguous_reserve_area() - reserve custom contiguous area
* @size: Size of the reserved area (in bytes),
* @base: Pointer to the base address of the reserved area, also used to return
* base address of the actually reserved area, optional, use pointer to
* 0 for any
* @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. This function allows to create custom reserved areas for specific
* devices.
*/
int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t *res_base,
phys_addr_t limit, const char *name)
{
phys_addr_t base = *res_base;
phys_addr_t alignment;
int ret = 0;
pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
(unsigned long)size, (unsigned long)base,
(unsigned long)limit);
/* Sanity checks */
if (cma_area_count == ARRAY_SIZE(cma_areas)) {
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 - 1, 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) {
ret = -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) {
ret = -ENOMEM;
goto err;
} else {
base = addr;
}
}
/*
* Each reserved area must be initialised later, when more kernel
* subsystems (like slab allocator) are available.
*/
cma_areas[cma_area_count].base = base;
cma_areas[cma_area_count].size = size;
cma_areas[cma_area_count].name = name;
cma_area_count++;
*res_base = base;
pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)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", (unsigned long)size / SZ_1M);
return ret;
}
/**
* dma_contiguous_add_device() - add device to custom contiguous reserved area
* @dev: Pointer to device structure.
* @base: Pointer to the base address of the reserved area returned by
* dma_contiguous_reserve_area() function, also used to return
*
* This function assigns the given device to the contiguous memory area
* reserved earlier by dma_contiguous_reserve_area() function.
*/
int __init dma_contiguous_add_device(struct device *dev, phys_addr_t base)
{
if (cma_map_count == ARRAY_SIZE(cma_maps)) {
pr_err("Not enough slots for CMA reserved regions!\n");
return -ENOSPC;
}
cma_maps[cma_map_count].dev = dev;
cma_maps[cma_map_count].base = base;
cma_map_count++;
return 0;
}
#ifdef CONFIG_OF
static void cma_assign_device_from_dt(struct device *dev)
{
struct device_node *node;
struct cma *cma;
const char *name;
u32 value;
node = of_parse_phandle(dev->of_node, "linux,contiguous-region", 0);
if (!node)
return;
if (of_property_read_u32(node, "reg", &value) && !value)
return;
if (of_property_read_string(node, "label", &name))
return;
cma = cma_get_area_by_name(name);
if (!cma)
return;
dev_set_cma_area(dev, cma);
pr_info("Assigned CMA region at %lx to %s device\n", (unsigned long)value, dev_name(dev));
}
static int cma_device_init_notifier_call(struct notifier_block *nb,
unsigned long event, void *data)
{
struct device *dev = data;
if (event == BUS_NOTIFY_ADD_DEVICE && dev->of_node)
cma_assign_device_from_dt(dev);
return NOTIFY_DONE;
}
static struct notifier_block cma_dev_init_nb = {
.notifier_call = cma_device_init_notifier_call,
};
#endif
static int __init cma_init_reserved_areas(void)
{
struct cma *cma;
int i;
for (i = 0; i < cma_area_count; i++) {
phys_addr_t base = PFN_DOWN(cma_areas[i].base);
unsigned int count = cma_areas[i].size >> PAGE_SHIFT;
cma = cma_create_area(base, count);
if (!IS_ERR(cma))
cma_areas[i].cma = cma;
}
dma_contiguous_def_area = cma_get_area(dma_contiguous_def_base);
for (i = 0; i < cma_map_count; i++) {
cma = cma_get_area(cma_maps[i].base);
dev_set_cma_area(cma_maps[i].dev, cma);
}
#ifdef CONFIG_OF
bus_register_notifier(&platform_bus_type, &cma_dev_init_nb);
#endif
return 0;
}
core_initcall(cma_init_reserved_areas);
/**
* 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);
struct page *page = NULL;
int ret;
int tries = 0;
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)
break;
pfn = cma->base_pfn + pageno;
ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
if (ret == 0) {
bitmap_set(cma->bitmap, pageno, count);
page = pfn_to_page(pfn);
break;
} else if (ret != -EBUSY) {
break;
}
tries++;
trace_dma_alloc_contiguous_retry(tries);
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__, page);
return page;
}
/**
* 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;
}