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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2012 ARM Ltd.
* Copyright (c) 2014 The Linux Foundation
*/
#include <linux/dma-direct.h>
#include <linux/dma-noncoherent.h>
#include <linux/dma-contiguous.h>
#include <linux/init.h>
#include <linux/genalloc.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
struct page **dma_common_find_pages(void *cpu_addr)
{
struct vm_struct *area = find_vm_area(cpu_addr);
if (!area || area->flags != VM_DMA_COHERENT)
return NULL;
return area->pages;
}
/*
* Remaps an array of PAGE_SIZE pages into another vm_area.
* Cannot be used in non-sleeping contexts
*/
void *dma_common_pages_remap(struct page **pages, size_t size,
pgprot_t prot, const void *caller)
{
void *vaddr;
vaddr = vmap(pages, size >> PAGE_SHIFT, VM_DMA_COHERENT, prot);
if (vaddr)
find_vm_area(vaddr)->pages = pages;
return vaddr;
}
/*
* Remaps an allocated contiguous region into another vm_area.
* Cannot be used in non-sleeping contexts
*/
void *dma_common_contiguous_remap(struct page *page, size_t size,
pgprot_t prot, const void *caller)
{
int count = size >> PAGE_SHIFT;
struct page **pages;
void *vaddr;
int i;
pages = kmalloc_array(count, sizeof(struct page *), GFP_KERNEL);
if (!pages)
return NULL;
for (i = 0; i < count; i++)
pages[i] = nth_page(page, i);
vaddr = vmap(pages, count, VM_DMA_COHERENT, prot);
kfree(pages);
return vaddr;
}
/*
* Unmaps a range previously mapped by dma_common_*_remap
*/
void dma_common_free_remap(void *cpu_addr, size_t size)
{
struct vm_struct *area = find_vm_area(cpu_addr);
if (!area || area->flags != VM_DMA_COHERENT) {
WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
return;
}
unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size));
vunmap(cpu_addr);
}
#ifdef CONFIG_DMA_DIRECT_REMAP
static struct gen_pool *atomic_pool __ro_after_init;
#define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K
static size_t atomic_pool_size __initdata = DEFAULT_DMA_COHERENT_POOL_SIZE;
static int __init early_coherent_pool(char *p)
{
atomic_pool_size = memparse(p, &p);
return 0;
}
early_param("coherent_pool", early_coherent_pool);
static gfp_t dma_atomic_pool_gfp(void)
{
if (IS_ENABLED(CONFIG_ZONE_DMA))
return GFP_DMA;
if (IS_ENABLED(CONFIG_ZONE_DMA32))
return GFP_DMA32;
return GFP_KERNEL;
}
static int __init dma_atomic_pool_init(void)
{
unsigned int pool_size_order = get_order(atomic_pool_size);
unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT;
struct page *page;
void *addr;
int ret;
if (dev_get_cma_area(NULL))
page = dma_alloc_from_contiguous(NULL, nr_pages,
pool_size_order, false);
else
page = alloc_pages(dma_atomic_pool_gfp(), pool_size_order);
if (!page)
goto out;
arch_dma_prep_coherent(page, atomic_pool_size);
atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
if (!atomic_pool)
goto free_page;
addr = dma_common_contiguous_remap(page, atomic_pool_size,
pgprot_dmacoherent(PAGE_KERNEL),
__builtin_return_address(0));
if (!addr)
goto destroy_genpool;
ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr,
page_to_phys(page), atomic_pool_size, -1);
if (ret)
goto remove_mapping;
gen_pool_set_algo(atomic_pool, gen_pool_first_fit_order_align, NULL);
pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n",
atomic_pool_size / 1024);
return 0;
remove_mapping:
dma_common_free_remap(addr, atomic_pool_size);
destroy_genpool:
gen_pool_destroy(atomic_pool);
atomic_pool = NULL;
free_page:
if (!dma_release_from_contiguous(NULL, page, nr_pages))
__free_pages(page, pool_size_order);
out:
pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n",
atomic_pool_size / 1024);
return -ENOMEM;
}
postcore_initcall(dma_atomic_pool_init);
bool dma_in_atomic_pool(void *start, size_t size)
{
if (unlikely(!atomic_pool))
return false;
return gen_pool_has_addr(atomic_pool, (unsigned long)start, size);
}
void *dma_alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags)
{
unsigned long val;
void *ptr = NULL;
if (!atomic_pool) {
WARN(1, "coherent pool not initialised!\n");
return NULL;
}
val = gen_pool_alloc(atomic_pool, size);
if (val) {
phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val);
*ret_page = pfn_to_page(__phys_to_pfn(phys));
ptr = (void *)val;
memset(ptr, 0, size);
}
return ptr;
}
bool dma_free_from_pool(void *start, size_t size)
{
if (!dma_in_atomic_pool(start, size))
return false;
gen_pool_free(atomic_pool, (unsigned long)start, size);
return true;
}
#endif /* CONFIG_DMA_DIRECT_REMAP */
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