// SPDX-License-Identifier: GPL-2.0
/*
* Coherent per-device memory handling.
* Borrowed from i386
*/
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>
struct dma_coherent_mem {
void *virt_base;
dma_addr_t device_base;
unsigned long pfn_base;
int size;
unsigned long *bitmap;
spinlock_t spinlock;
bool use_dev_dma_pfn_offset;
};
static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)
{
if (dev && dev->dma_mem)
return dev->dma_mem;
return NULL;
}
static inline dma_addr_t dma_get_device_base(struct device *dev,
struct dma_coherent_mem * mem)
{
if (mem->use_dev_dma_pfn_offset)
return (mem->pfn_base - dev->dma_pfn_offset) << PAGE_SHIFT;
else
return mem->device_base;
}
static int dma_init_coherent_memory(phys_addr_t phys_addr,
dma_addr_t device_addr, size_t size,
struct dma_coherent_mem **mem)
{
struct dma_coherent_mem *dma_mem = NULL;
void *mem_base = NULL;
int pages = size >> PAGE_SHIFT;
int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
int ret;
if (!size) {
ret = -EINVAL;
goto out;
}
mem_base = memremap(phys_addr, size, MEMREMAP_WC);
if (!mem_base) {
ret = -EINVAL;
goto out;
}
dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
if (!dma_mem) {
ret = -ENOMEM;
goto out;
}
dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
if (!dma_mem->bitmap) {
ret = -ENOMEM;
goto out;
}
dma_mem->virt_base = mem_base;
dma_mem->device_base = device_addr;
dma_mem->pfn_base = PFN_DOWN(phys_addr);
dma_mem->size = pages;
spin_lock_init(&dma_mem->spinlock);
*mem = dma_mem;
return 0;
out:
kfree(dma_mem);
if (mem_base)
memunmap(mem_base);
return ret;
}
static void dma_release_coherent_memory(struct dma_coherent_mem *mem)
{
if (!mem)
return;
memunmap(mem->virt_base);
kfree(mem->bitmap);
kfree(mem);
}
static int dma_assign_coherent_memory(struct device *dev,
struct dma_coherent_mem *mem)
{
if (!dev)
return -ENODEV;
if (dev->dma_mem)
return -EBUSY;
dev->dma_mem = mem;
return 0;
}
int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
dma_addr_t device_addr, size_t size)
{
struct dma_coherent_mem *mem;
int ret;
ret = dma_init_coherent_memory(phys_addr, device_addr, size, &mem);
if (ret)
return ret;
ret = dma_assign_coherent_memory(dev, mem);
if (ret)
dma_release_coherent_memory(mem);
return ret;
}
static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem,
ssize_t size, dma_addr_t *dma_handle)
{
int order = get_order(size);
unsigned long flags;
int pageno;
void *ret;
spin_lock_irqsave(&mem->spinlock, flags);
if (unlikely(size > (mem->size << PAGE_SHIFT)))
goto err;
pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
if (unlikely(pageno < 0))
goto err;
/*
* Memory was found in the coherent area.
*/
*dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
ret = mem->virt_base + (pageno << PAGE_SHIFT);
spin_unlock_irqrestore(&mem->spinlock, flags);
memset(ret, 0, size);
return ret;
err:
spin_unlock_irqrestore(&mem->spinlock, flags);
return NULL;
}
/**
* dma_alloc_from_dev_coherent() - allocate memory from device coherent pool
* @dev: device from which we allocate memory
* @size: size of requested memory area
* @dma_handle: This will be filled with the correct dma handle
* @ret: This pointer will be filled with the virtual address
* to allocated area.
*
* This function should be only called from per-arch dma_alloc_coherent()
* to support allocation from per-device coherent memory pools.
*
* Returns 0 if dma_alloc_coherent should continue with allocating from
* generic memory areas, or !0 if dma_alloc_coherent should return @ret.
*/
int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
dma_addr_t *dma_handle, void **ret)
{
struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
if (!mem)
return 0;
*ret = __dma_alloc_from_coherent(mem, size, dma_handle);
return 1;
}
void *dma_alloc_from_global_coherent(ssize_t size, dma_addr_t *dma_handle)
{
if (!dma_coherent_default_memory)
return NULL;
return __dma_alloc_from_coherent(dma_coherent_default_memory, size,
dma_handle);
}
static int __dma_release_from_coherent(struct dma_coherent_mem *mem,
int order, void *vaddr)
{
if (mem && vaddr >= mem->virt_base && vaddr <
(mem->virt_base + (mem->size << PAGE_SHIFT))) {
int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
unsigned long flags;
spin_lock_irqsave(&mem->spinlock, flags);
bitmap_release_region(mem->bitmap, page, order);
spin_unlock_irqrestore(&mem->spinlock, flags);
return 1;
}
return 0;
}
/**
* dma_release_from_dev_coherent() - free memory to device coherent memory pool
* @dev: device from which the memory was allocated
* @order: the order of pages allocated
* @vaddr: virtual address of allocated pages
*
* This checks whether the memory was allocated from the per-device
* coherent memory pool and if so, releases that memory.
*
* Returns 1 if we correctly released the memory, or 0 if the caller should
* proceed with releasing memory from generic pools.
*/
int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
{
struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
return __dma_release_from_coherent(mem, order, vaddr);
}
int dma_release_from_global_coherent(int order, void *vaddr)
{
if (!dma_coherent_default_memory)
return 0;
return __dma_release_from_coherent(dma_coherent_default_memory, order,
vaddr);
}
static int __dma_mmap_from_coherent(struct dma_coherent_mem *mem,
struct vm_area_struct *vma, void *vaddr, size_t size, int *ret)
{
if (mem && vaddr >= mem->virt_base && vaddr + size <=
(mem->virt_base + (mem->size << PAGE_SHIFT))) {
unsigned long off = vma->vm_pgoff;
int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
int user_count = vma_pages(vma);
int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
*ret = -ENXIO;
if (off < count && user_count <= count - off) {
unsigned long pfn = mem->pfn_base + start + off;
*ret = remap_pfn_range(vma, vma->vm_start, pfn,
user_count << PAGE_SHIFT,
vma->vm_page_prot);
}
return 1;
}
return 0;
}
/**
* dma_mmap_from_dev_coherent() - mmap memory from the device coherent pool
* @dev: device from which the memory was allocated
* @vma: vm_area for the userspace memory
* @vaddr: cpu address returned by dma_alloc_from_dev_coherent
* @size: size of the memory buffer allocated
* @ret: result from remap_pfn_range()
*
* This checks whether the memory was allocated from the per-device
* coherent memory pool and if so, maps that memory to the provided vma.
*
* Returns 1 if @vaddr belongs to the device coherent pool and the caller
* should return @ret, or 0 if they should proceed with mapping memory from
* generic areas.
*/
int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
void *vaddr, size_t size, int *ret)
{
struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret);
}
int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr,
size_t size, int *ret)
{
if (!dma_coherent_default_memory)
return 0;
return __dma_mmap_from_coherent(dma_coherent_default_memory, vma,
vaddr, size, ret);
}
/*
* Support for reserved memory regions defined in device tree
*/
#ifdef [31mCONFIG_OF_RESERVED_MEM[0m
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/of_reserved_mem.h>
static struct reserved_mem *dma_reserved_default_memory __initdata;
static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
{
struct dma_coherent_mem *mem = rmem->priv;
int ret;
if (!mem) {
ret = dma_init_coherent_memory(rmem->base, rmem->base,
rmem->size, &mem);
if (ret) {
pr_err("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
&rmem->base, (unsigned long)rmem->size / SZ_1M);
return ret;
}
}
mem->use_dev_dma_pfn_offset = true;
rmem->priv = mem;
dma_assign_coherent_memory(dev, mem);
return 0;
}
static void rmem_dma_device_release(struct reserved_mem *rmem,
struct device *dev)
{
if (dev)
dev->dma_mem = NULL;
}
static const struct reserved_mem_ops rmem_dma_ops = {
.device_init = rmem_dma_device_init,
.device_release = rmem_dma_device_release,
};
static int __init rmem_dma_setup(struct reserved_mem *rmem)
{
unsigned long node = rmem->fdt_node;
if (of_get_flat_dt_prop(node, "reusable", NULL))
return -EINVAL;
#ifdef [31mCONFIG_ARM[0m
if (!of_get_flat_dt_prop(node, "no-map", NULL)) {
pr_err("Reserved memory: regions without no-map are not yet supported\n");
return -EINVAL;
}
if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {
WARN(dma_reserved_default_memory,
"Reserved memory: region for default DMA coherent area is redefined\n");
dma_reserved_default_memory = rmem;
}
#endif
rmem->ops = &rmem_dma_ops;
pr_info("Reserved memory: created DMA memory pool at %pa, size %ld MiB\n",
&rmem->base, (unsigned long)rmem->size / SZ_1M);
return 0;
}
static int __init dma_init_reserved_memory(void)
{
const struct reserved_mem_ops *ops;
int ret;
if (!dma_reserved_default_memory)
return -ENOMEM;
ops = dma_reserved_default_memory->ops;
/*
* We rely on rmem_dma_device_init() does not propagate error of
* dma_assign_coherent_memory() for "NULL" device.
*/
ret = ops->device_init(dma_reserved_default_memory, NULL);
if (!ret) {
dma_coherent_default_memory = dma_reserved_default_memory->priv;
pr_info("DMA: default coherent area is set\n");
}
return ret;
}
core_initcall(dma_init_reserved_memory);
RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);
#endif