linux/arch/tile/kernel/pci-dma.c
Chris Metcalf 41bb38fc53 tile pci: enable IOMMU to support DMA for legacy devices
This change uses the TRIO IOMMU to map the PCI DMA space and physical
memory at different addresses.  We also now use the dma_mapping_ops
to provide support for non-PCI DMA, PCIe DMA (64-bit) and legacy PCI
DMA (32-bit).  We use the kernel's software I/O TLB framework
(i.e. bounce buffers) for the legacy 32-bit PCI device support since
there are a limited number of TLB entries in the IOMMU and it is
non-trivial to handle indexing, searching, matching, etc.  For 32-bit
devices the performance impact of bounce buffers should not be a concern.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-07-18 16:40:17 -04:00

587 lines
16 KiB
C

/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/swiotlb.h>
#include <linux/vmalloc.h>
#include <linux/export.h>
#include <asm/tlbflush.h>
#include <asm/homecache.h>
/* Generic DMA mapping functions: */
/*
* Allocate what Linux calls "coherent" memory. On TILEPro this is
* uncached memory; on TILE-Gx it is hash-for-home memory.
*/
#ifdef __tilepro__
#define PAGE_HOME_DMA PAGE_HOME_UNCACHED
#else
#define PAGE_HOME_DMA PAGE_HOME_HASH
#endif
static void *tile_dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp,
struct dma_attrs *attrs)
{
u64 dma_mask = dev->coherent_dma_mask ?: DMA_BIT_MASK(32);
int node = dev_to_node(dev);
int order = get_order(size);
struct page *pg;
dma_addr_t addr;
gfp |= __GFP_ZERO;
/*
* If the mask specifies that the memory be in the first 4 GB, then
* we force the allocation to come from the DMA zone. We also
* force the node to 0 since that's the only node where the DMA
* zone isn't empty. If the mask size is smaller than 32 bits, we
* may still not be able to guarantee a suitable memory address, in
* which case we will return NULL. But such devices are uncommon.
*/
if (dma_mask <= DMA_BIT_MASK(32)) {
gfp |= GFP_DMA;
node = 0;
}
pg = homecache_alloc_pages_node(node, gfp, order, PAGE_HOME_DMA);
if (pg == NULL)
return NULL;
addr = page_to_phys(pg);
if (addr + size > dma_mask) {
__homecache_free_pages(pg, order);
return NULL;
}
*dma_handle = addr;
return page_address(pg);
}
/*
* Free memory that was allocated with tile_dma_alloc_coherent.
*/
static void tile_dma_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle,
struct dma_attrs *attrs)
{
homecache_free_pages((unsigned long)vaddr, get_order(size));
}
/*
* The map routines "map" the specified address range for DMA
* accesses. The memory belongs to the device after this call is
* issued, until it is unmapped with dma_unmap_single.
*
* We don't need to do any mapping, we just flush the address range
* out of the cache and return a DMA address.
*
* The unmap routines do whatever is necessary before the processor
* accesses the memory again, and must be called before the driver
* touches the memory. We can get away with a cache invalidate if we
* can count on nothing having been touched.
*/
/* Set up a single page for DMA access. */
static void __dma_prep_page(struct page *page, unsigned long offset,
size_t size, enum dma_data_direction direction)
{
/*
* Flush the page from cache if necessary.
* On tilegx, data is delivered to hash-for-home L3; on tilepro,
* data is delivered direct to memory.
*
* NOTE: If we were just doing DMA_TO_DEVICE we could optimize
* this to be a "flush" not a "finv" and keep some of the
* state in cache across the DMA operation, but it doesn't seem
* worth creating the necessary flush_buffer_xxx() infrastructure.
*/
int home = page_home(page);
switch (home) {
case PAGE_HOME_HASH:
#ifdef __tilegx__
return;
#endif
break;
case PAGE_HOME_UNCACHED:
#ifdef __tilepro__
return;
#endif
break;
case PAGE_HOME_IMMUTABLE:
/* Should be going to the device only. */
BUG_ON(direction == DMA_FROM_DEVICE ||
direction == DMA_BIDIRECTIONAL);
return;
case PAGE_HOME_INCOHERENT:
/* Incoherent anyway, so no need to work hard here. */
return;
default:
BUG_ON(home < 0 || home >= NR_CPUS);
break;
}
homecache_finv_page(page);
#ifdef DEBUG_ALIGNMENT
/* Warn if the region isn't cacheline aligned. */
if (offset & (L2_CACHE_BYTES - 1) || (size & (L2_CACHE_BYTES - 1)))
pr_warn("Unaligned DMA to non-hfh memory: PA %#llx/%#lx\n",
PFN_PHYS(page_to_pfn(page)) + offset, size);
#endif
}
/* Make the page ready to be read by the core. */
static void __dma_complete_page(struct page *page, unsigned long offset,
size_t size, enum dma_data_direction direction)
{
#ifdef __tilegx__
switch (page_home(page)) {
case PAGE_HOME_HASH:
/* I/O device delivered data the way the cpu wanted it. */
break;
case PAGE_HOME_INCOHERENT:
/* Incoherent anyway, so no need to work hard here. */
break;
case PAGE_HOME_IMMUTABLE:
/* Extra read-only copies are not a problem. */
break;
default:
/* Flush the bogus hash-for-home I/O entries to memory. */
homecache_finv_map_page(page, PAGE_HOME_HASH);
break;
}
#endif
}
static void __dma_prep_pa_range(dma_addr_t dma_addr, size_t size,
enum dma_data_direction direction)
{
struct page *page = pfn_to_page(PFN_DOWN(dma_addr));
unsigned long offset = dma_addr & (PAGE_SIZE - 1);
size_t bytes = min(size, (size_t)(PAGE_SIZE - offset));
while (size != 0) {
__dma_prep_page(page, offset, bytes, direction);
size -= bytes;
++page;
offset = 0;
bytes = min((size_t)PAGE_SIZE, size);
}
}
static void __dma_complete_pa_range(dma_addr_t dma_addr, size_t size,
enum dma_data_direction direction)
{
struct page *page = pfn_to_page(PFN_DOWN(dma_addr));
unsigned long offset = dma_addr & (PAGE_SIZE - 1);
size_t bytes = min(size, (size_t)(PAGE_SIZE - offset));
while (size != 0) {
__dma_complete_page(page, offset, bytes, direction);
size -= bytes;
++page;
offset = 0;
bytes = min((size_t)PAGE_SIZE, size);
}
}
static int tile_dma_map_sg(struct device *dev, struct scatterlist *sglist,
int nents, enum dma_data_direction direction,
struct dma_attrs *attrs)
{
struct scatterlist *sg;
int i;
BUG_ON(!valid_dma_direction(direction));
WARN_ON(nents == 0 || sglist->length == 0);
for_each_sg(sglist, sg, nents, i) {
sg->dma_address = sg_phys(sg);
__dma_prep_pa_range(sg->dma_address, sg->length, direction);
#ifdef CONFIG_NEED_SG_DMA_LENGTH
sg->dma_length = sg->length;
#endif
}
return nents;
}
static void tile_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
int nents, enum dma_data_direction direction,
struct dma_attrs *attrs)
{
struct scatterlist *sg;
int i;
BUG_ON(!valid_dma_direction(direction));
for_each_sg(sglist, sg, nents, i) {
sg->dma_address = sg_phys(sg);
__dma_complete_pa_range(sg->dma_address, sg->length,
direction);
}
}
static dma_addr_t tile_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction direction,
struct dma_attrs *attrs)
{
BUG_ON(!valid_dma_direction(direction));
BUG_ON(offset + size > PAGE_SIZE);
__dma_prep_page(page, offset, size, direction);
return page_to_pa(page) + offset;
}
static void tile_dma_unmap_page(struct device *dev, dma_addr_t dma_address,
size_t size, enum dma_data_direction direction,
struct dma_attrs *attrs)
{
BUG_ON(!valid_dma_direction(direction));
__dma_complete_page(pfn_to_page(PFN_DOWN(dma_address)),
dma_address & PAGE_OFFSET, size, direction);
}
static void tile_dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle,
size_t size,
enum dma_data_direction direction)
{
BUG_ON(!valid_dma_direction(direction));
__dma_complete_pa_range(dma_handle, size, direction);
}
static void tile_dma_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle, size_t size,
enum dma_data_direction direction)
{
__dma_prep_pa_range(dma_handle, size, direction);
}
static void tile_dma_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sglist, int nelems,
enum dma_data_direction direction)
{
struct scatterlist *sg;
int i;
BUG_ON(!valid_dma_direction(direction));
WARN_ON(nelems == 0 || sglist->length == 0);
for_each_sg(sglist, sg, nelems, i) {
dma_sync_single_for_cpu(dev, sg->dma_address,
sg_dma_len(sg), direction);
}
}
static void tile_dma_sync_sg_for_device(struct device *dev,
struct scatterlist *sglist, int nelems,
enum dma_data_direction direction)
{
struct scatterlist *sg;
int i;
BUG_ON(!valid_dma_direction(direction));
WARN_ON(nelems == 0 || sglist->length == 0);
for_each_sg(sglist, sg, nelems, i) {
dma_sync_single_for_device(dev, sg->dma_address,
sg_dma_len(sg), direction);
}
}
static inline int
tile_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
return 0;
}
static inline int
tile_dma_supported(struct device *dev, u64 mask)
{
return 1;
}
static struct dma_map_ops tile_default_dma_map_ops = {
.alloc = tile_dma_alloc_coherent,
.free = tile_dma_free_coherent,
.map_page = tile_dma_map_page,
.unmap_page = tile_dma_unmap_page,
.map_sg = tile_dma_map_sg,
.unmap_sg = tile_dma_unmap_sg,
.sync_single_for_cpu = tile_dma_sync_single_for_cpu,
.sync_single_for_device = tile_dma_sync_single_for_device,
.sync_sg_for_cpu = tile_dma_sync_sg_for_cpu,
.sync_sg_for_device = tile_dma_sync_sg_for_device,
.mapping_error = tile_dma_mapping_error,
.dma_supported = tile_dma_supported
};
struct dma_map_ops *tile_dma_map_ops = &tile_default_dma_map_ops;
EXPORT_SYMBOL(tile_dma_map_ops);
/* Generic PCI DMA mapping functions */
static void *tile_pci_dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp,
struct dma_attrs *attrs)
{
int node = dev_to_node(dev);
int order = get_order(size);
struct page *pg;
dma_addr_t addr;
gfp |= __GFP_ZERO;
pg = homecache_alloc_pages_node(node, gfp, order, PAGE_HOME_DMA);
if (pg == NULL)
return NULL;
addr = page_to_phys(pg);
*dma_handle = phys_to_dma(dev, addr);
return page_address(pg);
}
/*
* Free memory that was allocated with tile_pci_dma_alloc_coherent.
*/
static void tile_pci_dma_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle,
struct dma_attrs *attrs)
{
homecache_free_pages((unsigned long)vaddr, get_order(size));
}
static int tile_pci_dma_map_sg(struct device *dev, struct scatterlist *sglist,
int nents, enum dma_data_direction direction,
struct dma_attrs *attrs)
{
struct scatterlist *sg;
int i;
BUG_ON(!valid_dma_direction(direction));
WARN_ON(nents == 0 || sglist->length == 0);
for_each_sg(sglist, sg, nents, i) {
sg->dma_address = sg_phys(sg);
__dma_prep_pa_range(sg->dma_address, sg->length, direction);
sg->dma_address = phys_to_dma(dev, sg->dma_address);
#ifdef CONFIG_NEED_SG_DMA_LENGTH
sg->dma_length = sg->length;
#endif
}
return nents;
}
static void tile_pci_dma_unmap_sg(struct device *dev,
struct scatterlist *sglist, int nents,
enum dma_data_direction direction,
struct dma_attrs *attrs)
{
struct scatterlist *sg;
int i;
BUG_ON(!valid_dma_direction(direction));
for_each_sg(sglist, sg, nents, i) {
sg->dma_address = sg_phys(sg);
__dma_complete_pa_range(sg->dma_address, sg->length,
direction);
}
}
static dma_addr_t tile_pci_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction direction,
struct dma_attrs *attrs)
{
BUG_ON(!valid_dma_direction(direction));
BUG_ON(offset + size > PAGE_SIZE);
__dma_prep_page(page, offset, size, direction);
return phys_to_dma(dev, page_to_pa(page) + offset);
}
static void tile_pci_dma_unmap_page(struct device *dev, dma_addr_t dma_address,
size_t size,
enum dma_data_direction direction,
struct dma_attrs *attrs)
{
BUG_ON(!valid_dma_direction(direction));
dma_address = dma_to_phys(dev, dma_address);
__dma_complete_page(pfn_to_page(PFN_DOWN(dma_address)),
dma_address & PAGE_OFFSET, size, direction);
}
static void tile_pci_dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle,
size_t size,
enum dma_data_direction direction)
{
BUG_ON(!valid_dma_direction(direction));
dma_handle = dma_to_phys(dev, dma_handle);
__dma_complete_pa_range(dma_handle, size, direction);
}
static void tile_pci_dma_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle,
size_t size,
enum dma_data_direction
direction)
{
dma_handle = dma_to_phys(dev, dma_handle);
__dma_prep_pa_range(dma_handle, size, direction);
}
static void tile_pci_dma_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sglist,
int nelems,
enum dma_data_direction direction)
{
struct scatterlist *sg;
int i;
BUG_ON(!valid_dma_direction(direction));
WARN_ON(nelems == 0 || sglist->length == 0);
for_each_sg(sglist, sg, nelems, i) {
dma_sync_single_for_cpu(dev, sg->dma_address,
sg_dma_len(sg), direction);
}
}
static void tile_pci_dma_sync_sg_for_device(struct device *dev,
struct scatterlist *sglist,
int nelems,
enum dma_data_direction direction)
{
struct scatterlist *sg;
int i;
BUG_ON(!valid_dma_direction(direction));
WARN_ON(nelems == 0 || sglist->length == 0);
for_each_sg(sglist, sg, nelems, i) {
dma_sync_single_for_device(dev, sg->dma_address,
sg_dma_len(sg), direction);
}
}
static inline int
tile_pci_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
return 0;
}
static inline int
tile_pci_dma_supported(struct device *dev, u64 mask)
{
return 1;
}
static struct dma_map_ops tile_pci_default_dma_map_ops = {
.alloc = tile_pci_dma_alloc_coherent,
.free = tile_pci_dma_free_coherent,
.map_page = tile_pci_dma_map_page,
.unmap_page = tile_pci_dma_unmap_page,
.map_sg = tile_pci_dma_map_sg,
.unmap_sg = tile_pci_dma_unmap_sg,
.sync_single_for_cpu = tile_pci_dma_sync_single_for_cpu,
.sync_single_for_device = tile_pci_dma_sync_single_for_device,
.sync_sg_for_cpu = tile_pci_dma_sync_sg_for_cpu,
.sync_sg_for_device = tile_pci_dma_sync_sg_for_device,
.mapping_error = tile_pci_dma_mapping_error,
.dma_supported = tile_pci_dma_supported
};
struct dma_map_ops *gx_pci_dma_map_ops = &tile_pci_default_dma_map_ops;
EXPORT_SYMBOL(gx_pci_dma_map_ops);
/* PCI DMA mapping functions for legacy PCI devices */
#ifdef CONFIG_SWIOTLB
static void *tile_swiotlb_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp,
struct dma_attrs *attrs)
{
gfp |= GFP_DMA;
return swiotlb_alloc_coherent(dev, size, dma_handle, gfp);
}
static void tile_swiotlb_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_addr,
struct dma_attrs *attrs)
{
swiotlb_free_coherent(dev, size, vaddr, dma_addr);
}
static struct dma_map_ops pci_swiotlb_dma_ops = {
.alloc = tile_swiotlb_alloc_coherent,
.free = tile_swiotlb_free_coherent,
.map_page = swiotlb_map_page,
.unmap_page = swiotlb_unmap_page,
.map_sg = swiotlb_map_sg_attrs,
.unmap_sg = swiotlb_unmap_sg_attrs,
.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
.sync_single_for_device = swiotlb_sync_single_for_device,
.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
.sync_sg_for_device = swiotlb_sync_sg_for_device,
.dma_supported = swiotlb_dma_supported,
.mapping_error = swiotlb_dma_mapping_error,
};
struct dma_map_ops *gx_legacy_pci_dma_map_ops = &pci_swiotlb_dma_ops;
#else
struct dma_map_ops *gx_legacy_pci_dma_map_ops;
#endif
EXPORT_SYMBOL(gx_legacy_pci_dma_map_ops);
#ifdef CONFIG_ARCH_HAS_DMA_SET_COHERENT_MASK
int dma_set_coherent_mask(struct device *dev, u64 mask)
{
struct dma_map_ops *dma_ops = get_dma_ops(dev);
/* Handle legacy PCI devices with limited memory addressability. */
if (((dma_ops == gx_pci_dma_map_ops) ||
(dma_ops == gx_legacy_pci_dma_map_ops)) &&
(mask <= DMA_BIT_MASK(32))) {
if (mask > dev->archdata.max_direct_dma_addr)
mask = dev->archdata.max_direct_dma_addr;
}
if (!dma_supported(dev, mask))
return -EIO;
dev->coherent_dma_mask = mask;
return 0;
}
EXPORT_SYMBOL(dma_set_coherent_mask);
#endif