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|
/*
* SWIOTLB-based DMA API implementation
*
* Copyright (C) 2012 ARM Ltd.
* Author: Catalin Marinas <catalin.marinas@arm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/gfp.h>
#include <linux/acpi.h>
#include <linux/memblock.h>
#include <linux/cache.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/genalloc.h>
#include <linux/dma-direct.h>
#include <linux/dma-noncoherent.h>
#include <linux/dma-contiguous.h>
#include <linux/vmalloc.h>
#include <linux/swiotlb.h>
#include <linux/pci.h>
#include <asm/cacheflush.h>
pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot,
unsigned long attrs)
{
if (!dev_is_dma_coherent(dev) || (attrs & DMA_ATTR_WRITE_COMBINE))
return pgprot_writecombine(prot);
return prot;
}
void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
size_t size, enum dma_data_direction dir)
{
__dma_map_area(phys_to_virt(paddr), size, dir);
}
void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
size_t size, enum dma_data_direction dir)
{
__dma_unmap_area(phys_to_virt(paddr), size, dir);
}
void arch_dma_prep_coherent(struct page *page, size_t size)
{
__dma_flush_area(page_address(page), size);
}
#ifdef CONFIG_IOMMU_DMA
static int __swiotlb_get_sgtable_page(struct sg_table *sgt,
struct page *page, size_t size)
{
int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
if (!ret)
sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
return ret;
}
static int __swiotlb_mmap_pfn(struct vm_area_struct *vma,
unsigned long pfn, size_t size)
{
int ret = -ENXIO;
unsigned long nr_vma_pages = vma_pages(vma);
unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned long off = vma->vm_pgoff;
if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) {
ret = remap_pfn_range(vma, vma->vm_start,
pfn + off,
vma->vm_end - vma->vm_start,
vma->vm_page_prot);
}
return ret;
}
#endif /* CONFIG_IOMMU_DMA */
static int __init arm64_dma_init(void)
{
WARN_TAINT(ARCH_DMA_MINALIGN < cache_line_size(),
TAINT_CPU_OUT_OF_SPEC,
"ARCH_DMA_MINALIGN smaller than CTR_EL0.CWG (%d < %d)",
ARCH_DMA_MINALIGN, cache_line_size());
return dma_atomic_pool_init(GFP_DMA32, __pgprot(PROT_NORMAL_NC));
}
arch_initcall(arm64_dma_init);
#ifdef CONFIG_IOMMU_DMA
#include <linux/dma-iommu.h>
#include <linux/platform_device.h>
#include <linux/amba/bus.h>
/* Thankfully, all cache ops are by VA so we can ignore phys here */
static void flush_page(struct device *dev, const void *virt, phys_addr_t phys)
{
__dma_flush_area(virt, PAGE_SIZE);
}
static void *__iommu_alloc_attrs(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp,
unsigned long attrs)
{
bool coherent = dev_is_dma_coherent(dev);
int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
size_t iosize = size;
void *addr;
if (WARN(!dev, "cannot create IOMMU mapping for unknown device\n"))
return NULL;
size = PAGE_ALIGN(size);
/*
* Some drivers rely on this, and we probably don't want the
* possibility of stale kernel data being read by devices anyway.
*/
gfp |= __GFP_ZERO;
if (!gfpflags_allow_blocking(gfp)) {
struct page *page;
/*
* In atomic context we can't remap anything, so we'll only
* get the virtually contiguous buffer we need by way of a
* physically contiguous allocation.
*/
if (coherent) {
page = alloc_pages(gfp, get_order(size));
addr = page ? page_address(page) : NULL;
} else {
addr = dma_alloc_from_pool(size, &page, gfp);
}
if (!addr)
return NULL;
*handle = iommu_dma_map_page(dev, page, 0, iosize, ioprot);
if (*handle == DMA_MAPPING_ERROR) {
if (coherent)
__free_pages(page, get_order(size));
else
dma_free_from_pool(addr, size);
addr = NULL;
}
} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
struct page *page;
page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
get_order(size), gfp & __GFP_NOWARN);
if (!page)
return NULL;
*handle = iommu_dma_map_page(dev, page, 0, iosize, ioprot);
if (*handle == DMA_MAPPING_ERROR) {
dma_release_from_contiguous(dev, page,
size >> PAGE_SHIFT);
return NULL;
}
addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
prot,
__builtin_return_address(0));
if (addr) {
if (!coherent)
__dma_flush_area(page_to_virt(page), iosize);
memset(addr, 0, size);
} else {
iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs);
dma_release_from_contiguous(dev, page,
size >> PAGE_SHIFT);
}
} else {
pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
struct page **pages;
pages = iommu_dma_alloc(dev, iosize, gfp, attrs, ioprot,
handle, flush_page);
if (!pages)
return NULL;
addr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
__builtin_return_address(0));
if (!addr)
iommu_dma_free(dev, pages, iosize, handle);
}
return addr;
}
static void __iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, unsigned long attrs)
{
size_t iosize = size;
size = PAGE_ALIGN(size);
/*
* @cpu_addr will be one of 4 things depending on how it was allocated:
* - A remapped array of pages for contiguous allocations.
* - A remapped array of pages from iommu_dma_alloc(), for all
* non-atomic allocations.
* - A non-cacheable alias from the atomic pool, for atomic
* allocations by non-coherent devices.
* - A normal lowmem address, for atomic allocations by
* coherent devices.
* Hence how dodgy the below logic looks...
*/
if (dma_in_atomic_pool(cpu_addr, size)) {
iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
dma_free_from_pool(cpu_addr, size);
} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
struct page *page = vmalloc_to_page(cpu_addr);
iommu_dma_unmap_page(dev, handle, iosize, 0, attrs);
dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
dma_common_free_remap(cpu_addr, size, VM_USERMAP);
} else if (is_vmalloc_addr(cpu_addr)){
struct vm_struct *area = find_vm_area(cpu_addr);
if (WARN_ON(!area || !area->pages))
return;
iommu_dma_free(dev, area->pages, iosize, &handle
|