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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
*
* Provide default implementations of the DMA mapping callbacks for
* busses using the iommu infrastructure
*/
#include <linux/dma-direct.h>
#include <linux/pci.h>
#include <asm/iommu.h>
#ifdef CONFIG_ARCH_HAS_DMA_MAP_DIRECT
#define can_map_direct(dev, addr) \
((dev)->bus_dma_limit >= phys_to_dma((dev), (addr)))
bool arch_dma_map_page_direct(struct device *dev, phys_addr_t addr)
{
if (likely(!dev->bus_dma_limit))
return false;
return can_map_direct(dev, addr);
}
#define is_direct_handle(dev, h) ((h) >= (dev)->archdata.dma_offset)
bool arch_dma_unmap_page_direct(struct device *dev, dma_addr_t dma_handle)
{
if (likely(!dev->bus_dma_limit))
return false;
return is_direct_handle(dev, dma_handle);
}
bool arch_dma_map_sg_direct(struct device *dev, struct scatterlist *sg,
int nents)
{
struct scatterlist *s;
int i;
if (likely(!dev->bus_dma_limit))
return false;
for_each_sg(sg, s, nents, i) {
if (!can_map_direct(dev, sg_phys(s) + s->offset + s->length))
return false;
}
return true;
}
bool arch_dma_unmap_sg_direct(struct device *dev, struct scatterlist *sg,
int nents)
{
struct scatterlist *s;
int i;
if (likely(!dev->bus_dma_limit))
return false;
for_each_sg(sg, s, nents, i) {
if (!is_direct_handle(dev, s->dma_address + s->length))
return false;
}
return true;
}
#endif /* CONFIG_ARCH_HAS_DMA_MAP_DIRECT */
/*
* Generic iommu implementation
*/
/* Allocates a contiguous real buffer and creates mappings over it.
* Returns the virtual address of the buffer and sets dma_handle
* to the dma address (mapping) of the first page.
*/
static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t flag,
unsigned long attrs)
{
return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
dma_handle, dev->coherent_dma_mask, flag,
dev_to_node(dev));
}
static void dma_iommu_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle,
unsigned long attrs)
{
iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
}
/* Creates TCEs for a user provided buffer. The user buffer must be
* contiguous real kernel storage (not vmalloc). The address passed here
* comprises a page address and offset into that page. The dma_addr_t
* returned will point to the same byte within the page as was passed in.
*/
static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction direction,
unsigned long attrs)
{
return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
size, dma_get_mask(dev), direction, attrs);
}
static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
size_t size, enum dma_data_direction direction,
unsigned long attrs)
{
iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
attrs);
}
static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
int nelems, enum dma_data_direction direction,
unsigned long attrs)
{
return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
dma_get_mask(dev), direction, attrs);
}
static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
int nelems, enum dma_data_direction direction,
unsigned long attrs)
{
ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems,
direction, attrs);
}
static bool dma_iommu_bypass_supported(struct device *dev, u64 mask)
{
struct pci_dev *pdev = to_pci_dev(dev);
struct pci_controller *phb = pci_bus_to_host(pdev->bus);
if (iommu_fixed_is_weak || !phb->controller_ops.iommu_bypass_supported)
return false;
return phb->controller_ops.iommu_bypass_supported(pdev, mask);
}
/* We support DMA to/from any memory page via the iommu */
int dma_iommu_dma_supported(struct device *dev, u64 mask)
{
struct iommu_table *tbl;
if (dev_is_pci(dev) && dma_iommu_bypass_supported(dev, mask)) {
/*
* dma_iommu_bypass_supported() sets dma_max when there is
* 1:1 mapping but it is somehow limited.
* ibm,pmemory is one example.
*/
dev->dma_ops_bypass = dev->bus_dma_limit == 0;
if (!dev->dma_ops_bypass)
dev_warn(dev,
"iommu: 64-bit OK but direct DMA is limited by %llx\n",
dev->bus_dma_limit);
else
dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n");
return 1;
}
tbl = get_iommu_table_base(dev);
if (!tbl) {
dev_err(dev, "Warning: IOMMU dma not supported: mask 0x%08llx, table unavailable\n", mask);
return 0;
}
if (tbl->it_offset > (mask >> tbl->it_page_shift)) {
dev_info(dev, "Warning: IOMMU offset too big for device mask\n");
dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n",
mask, tbl->it_offset << tbl->it_page_shift);
return 0;
}
dev_dbg(dev, "iommu: not 64-bit, using default ops\n");
dev->dma_ops_bypass = false;
return 1;
}
u64 dma_iommu_get_required_mask(struct device *dev)
{
struct iommu_table *tbl = get_iommu_table_base(dev);
u64 mask;
if (dev_is_pci(dev)) {
u64 bypass_mask = dma_direct_get_required_mask(dev);
if (dma_iommu_dma_supported(dev, bypass_mask)) {
dev_info(dev, "%s: returning bypass mask 0x%llx\n", __func__, bypass_mask);
return bypass_mask;
}
}
if (!tbl)
return 0;
mask = 1ULL << (fls_long(tbl->it_offset + tbl->it_size) +
tbl->it_page_shift - 1);
mask += mask - 1;
return mask;
}
const struct dma_map_ops dma_iommu_ops = {
.alloc = dma_iommu_alloc_coherent,
.free = dma_iommu_free_coherent,
.map_sg = dma_iommu_map_sg,
.unmap_sg = dma_iommu_unmap_sg,
.dma_supported = dma_iommu_dma_supported,
.map_page = dma_iommu_map_page,
.unmap_page = dma_iommu_unmap_page,
.get_required_mask = dma_iommu_get_required_mask,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
.alloc_pages_op = dma_common_alloc_pages,
.free_pages = dma_common_free_pages,
};
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