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/*
* Device tree based initialization code for reserved memory.
*
* Copyright (c) 2013 Samsung Electronics Co., Ltd.
* http://www.samsung.com
* Author: Marek Szyprowski <m.szyprowski@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.
*/
#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/sizes.h>
#include <linux/mm_types.h>
#include <linux/dma-contiguous.h>
#include <linux/dma-mapping.h>
#include <linux/of_reserved_mem.h>
#define MAX_RESERVED_REGIONS 16
struct reserved_mem {
phys_addr_t base;
unsigned long size;
struct cma *cma;
char name[32];
};
static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
static int reserved_mem_count;
static int __init fdt_scan_reserved_mem(unsigned long node, const char *uname,
int depth, void *data)
{
struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
phys_addr_t base, size;
int is_cma, is_reserved;
unsigned long len;
const char *status;
__be32 *prop;
is_cma = IS_ENABLED(CONFIG_DMA_CMA) &&
of_flat_dt_is_compatible(node, "linux,contiguous-memory-region");
is_reserved = of_flat_dt_is_compatible(node, "reserved-memory-region");
if (!is_reserved && !is_cma) {
/* ignore node and scan next one */
return 0;
}
status = of_get_flat_dt_prop(node, "status", &len);
if (status && strcmp(status, "okay") != 0) {
/* ignore disabled node nad scan next one */
return 0;
}
prop = of_get_flat_dt_prop(node, "reg", &len);
if (!prop || (len < (dt_root_size_cells + dt_root_addr_cells) *
sizeof(__be32))) {
pr_err("Reserved mem: node %s, incorrect \"reg\" property\n",
uname);
/* ignore node and scan next one */
return 0;
}
base = dt_mem_next_cell(dt_root_addr_cells, &prop);
size = dt_mem_next_cell(dt_root_size_cells, &prop);
if (!size) {
/* ignore node and scan next one */
return 0;
}
pr_info("Reserved mem: found %s, memory base %lx, size %ld MiB\n",
uname, (unsigned long)base, (unsigned long)size / SZ_1M);
if (reserved_mem_count == ARRAY_SIZE(reserved_mem))
return -ENOSPC;
rmem->base = base;
rmem->size = size;
strlcpy(rmem->name, uname, sizeof(rmem->name));
if (is_cma) {
struct cma *cma;
if (dma_contiguous_reserve_area(size, base, 0, &cma) == 0) {
rmem->cma = cma;
reserved_mem_count++;
if (of_get_flat_dt_prop(node,
"linux,default-contiguous-region",
NULL))
dma_contiguous_set_default(cma);
}
} else if (is_reserved) {
if (memblock_remove(base, size) == 0)
reserved_mem_count++;
else
pr_err("Failed to reserve memory for %s\n", uname);
}
return 0;
}
static struct reserved_mem *get_dma_memory_region(struct device *dev)
{
struct device_node *node;
const char *name;
int i;
node = of_parse_phandle(dev->of_node, "memory-region", 0);
if (!node)
return NULL;
name = kbasename(node->full_name);
for (i = 0; i < reserved_mem_count; i++)
if (strcmp(name, reserved_mem[i].name) == 0)
return &reserved_mem[i];
return NULL;
}
/**
* of_reserved_mem_device_init() - assign reserved memory region to given device
*
* This function assign memory region pointed by "memory-region" device tree
* property to the given device.
*/
void of_reserved_mem_device_init(struct device *dev)
{
struct reserved_mem *region = get_dma_memory_region(dev);
if (!region)
return;
if (region->cma) {
dev_set_cma_area(dev, region->cma);
pr_info("Assigned CMA %s to %s device\n", region->name,
dev_name(dev));
} else {
if (dma_declare_coherent_memory(dev, region->base, region->base,
region->size, DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE) != 0)
pr_info("Declared reserved memory %s to %s device\n",
region->name, dev_name(dev));
}
}
/**
* of_reserved_mem_device_release() - release reserved memory device structures
*
* This function releases structures allocated for memory region handling for
* the given device.
*/
void of_reserved_mem_device_release(struct device *dev)
{
struct reserved_mem *region = get_dma_memory_region(dev);
if (!region && !region->cma)
dma_release_declared_memory(dev);
}
/**
* early_init_dt_scan_reserved_mem() - create reserved memory regions
*
* This function grabs memory from early allocator for device exclusive use
* defined in device tree structures. It should be called by arch specific code
* once the early allocator (memblock) has been activated and all other
* subsystems have already allocated/reserved memory.
*/
void __init early_init_dt_scan_reserved_mem(void)
{
of_scan_flat_dt_by_path("/memory/reserved-memory",
fdt_scan_reserved_mem, NULL);
}
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