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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>
/*
* Generic iommu implementation
*/
/*
* The coherent mask may be smaller than the real mask, check if we can
* really use a direct window.
*/
static inline bool dma_iommu_alloc_bypass(struct device *dev)
{
return dev->archdata.iommu_bypass && !iommu_fixed_is_weak &&
dma_direct_supported(dev, dev->coherent_dma_mask);
}
static inline bool dma_iommu_map_bypass(struct device *dev,
unsigned long attrs)
{
return dev->archdata.iommu_bypass &&
(!iommu_fixed_is_weak || (attrs & DMA_ATTR_WEAK_ORDERING));
}
/* 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)
{
if (dma_iommu_alloc_bypass(dev))
return dma_direct_alloc(dev, size, dma_handle, flag, 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)
{
if (dma_iommu_alloc_bypass(dev))
dma_direct_free(dev, size, vaddr, dma_handle, attrs);
else
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)
{
if (dma_iommu_map_bypass(dev, attrs))
return dma_direct_map_page(dev, page, offset, size, direction,
attrs);
return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
size, device_to_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)
{
if (!dma_iommu_map_bypass(dev, 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)
{
if (dma_iommu_map_bypass(dev, attrs))
return dma_direct_map_sg(dev, sglist, nelems, direction, attrs);
return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
device_to_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)
{
if (!dma_iommu_map_bypass(dev, 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);
return phb->controller_ops.iommu_bypass_supported &&
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 = get_iommu_table_base(dev);
if (!tbl) {
dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
", table unavailable\n", mask);
return 0;
}
if (dev_is_pci(dev) && dma_iommu_bypass_supported(dev, mask)) {
dev->archdata.iommu_bypass = true;
dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n");
return 1;
}
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->archdata.iommu_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 (!tbl)
return 0;
if (dev_is_pci(dev)) {
u64 bypass_mask = dma_direct_get_required_mask(dev);
if (dma_iommu_bypass_supported(dev, bypass_mask))
return bypass_mask;
}
mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 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,
};
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