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/*
* Dynamic DMA mapping support.
*/
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/module.h>
#include <asm/io.h>
#include <asm-xen/balloon.h>
/* Map a set of buffers described by scatterlist in streaming
* mode for DMA. This is the scatter-gather version of the
* above pci_map_single interface. Here the scatter gather list
* elements are each tagged with the appropriate dma address
* and length. They are obtained via sg_dma_{address,length}(SG).
*
* NOTE: An implementation may be able to use a smaller number of
* DMA address/length pairs than there are SG table elements.
* (for example via virtual mapping capabilities)
* The routine returns the number of addr/length pairs actually
* used, at most nents.
*
* Device ownership issues as mentioned above for pci_map_single are
* the same here.
*/
int dma_map_sg(struct device *hwdev, struct scatterlist *sg,
int nents, int direction)
{
int i;
BUG_ON(direction == DMA_NONE);
for (i = 0; i < nents; i++ ) {
struct scatterlist *s = &sg[i];
BUG_ON(!s->page);
s->dma_address = virt_to_bus(page_address(s->page) +s->offset);
s->dma_length = s->length;
}
return nents;
}
EXPORT_SYMBOL(dma_map_sg);
/* Unmap a set of streaming mode DMA translations.
* Again, cpu read rules concerning calls here are the same as for
* pci_unmap_single() above.
*/
void dma_unmap_sg(struct device *dev, struct scatterlist *sg,
int nents, int dir)
{
int i;
for (i = 0; i < nents; i++) {
struct scatterlist *s = &sg[i];
BUG_ON(s->page == NULL);
BUG_ON(s->dma_address == 0);
dma_unmap_single(dev, s->dma_address, s->dma_length, dir);
}
}
struct dma_coherent_mem {
void *virt_base;
u32 device_base;
int size;
int flags;
unsigned long *bitmap;
};
static void
xen_contig_memory(unsigned long vstart, unsigned int order)
{
/*
* Ensure multi-page extents are contiguous in machine memory.
* This code could be cleaned up some, and the number of
* hypercalls reduced.
*/
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
unsigned long pfn, i, flags;
scrub_pages(vstart, 1 << order);
balloon_lock(flags);
/* 1. Zap current PTEs, giving away the underlying pages. */
for (i = 0; i < (1<<order); i++) {
pgd = pgd_offset_k( (vstart + (i*PAGE_SIZE)));
pud = pud_offset(pgd, (vstart + (i*PAGE_SIZE)));
pmd = pmd_offset(pud, (vstart + (i*PAGE_SIZE)));
pte = pte_offset_kernel(pmd, (vstart + (i*PAGE_SIZE)));
pfn = pte->pte >> PAGE_SHIFT;
xen_l1_entry_update(pte, 0);
phys_to_machine_mapping[(__pa(vstart)>>PAGE_SHIFT)+i] =
(u32)INVALID_P2M_ENTRY;
if (HYPERVISOR_dom_mem_op(MEMOP_decrease_reservation,
&pfn, 1, 0) != 1) BUG();
}
/* 2. Get a new contiguous memory extent. */
if (HYPERVISOR_dom_mem_op(MEMOP_increase_reservation,
&pfn, 1, order) != 1) BUG();
/* 3. Map the new extent in place of old pages. */
for (i = 0; i < (1<<order); i++) {
pgd = pgd_offset_k( (vstart + (i*PAGE_SIZE)));
pud = pud_offset(pgd, (vstart + (i*PAGE_SIZE)));
pmd = pmd_offset(pud, (vstart + (i*PAGE_SIZE)));
pte = pte_offset_kernel(pmd, (vstart + (i*PAGE_SIZE)));
xen_l1_entry_update(
pte, ((pfn+i)<<PAGE_SHIFT)|__PAGE_KERNEL);
xen_machphys_update(
pfn+i, (__pa(vstart)>>PAGE_SHIFT)+i);
phys_to_machine_mapping[(__pa(vstart)>>PAGE_SHIFT)+i] =
pfn+i;
}
/* Flush updates through and flush the TLB. */
xen_tlb_flush();
balloon_unlock(flags);
}
void *dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, unsigned gfp)
{
void *ret;
unsigned int order = get_order(size);
unsigned long vstart;
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
/* ignore region specifiers */
gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
if (mem) {
int page = bitmap_find_free_region(mem->bitmap, mem->size,
order);
if (page >= 0) {
*dma_handle = mem->device_base + (page << PAGE_SHIFT);
ret = mem->virt_base + (page << PAGE_SHIFT);
memset(ret, 0, size);
return ret;
}
if (mem->flags & DMA_MEMORY_EXCLUSIVE)
return NULL;
}
if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
gfp |= GFP_DMA;
vstart = __get_free_pages(gfp, order);
ret = (void *)vstart;
if (ret == NULL)
return ret;
xen_contig_memory(vstart, order);
memset(ret, 0, size);
*dma_handle = virt_to_bus(ret);
return ret;
}
EXPORT_SYMBOL(dma_alloc_coherent);
void dma_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle)
{
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
int order = get_order(size);
if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
bitmap_release_region(mem->bitmap, page, order);
} else
free_pages((unsigned long)vaddr, order);
}
EXPORT_SYMBOL(dma_free_coherent);
#if 0
int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
dma_addr_t device_addr, size_t size, int flags)
{
void __iomem *mem_base;
int pages = size >> PAGE_SHIFT;
int bitmap_size = (pages + 31)/32;
if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
goto out;
if (!size)
goto out;
if (dev->dma_mem)
goto out;
/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
mem_base = ioremap(bus_addr, size);
if (!mem_base)
goto out;
dev->dma_mem = kmalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
if (!dev->dma_mem)
goto out;
memset(dev->dma_mem, 0, sizeof(struct dma_coherent_mem));
dev->dma_mem->bitmap = kmalloc(bitmap_size, GFP_KERNEL);
if (!dev->dma_mem->bitmap)
goto free1_out;
memset(dev->dma_mem->bitmap, 0, bitmap_size);
dev->dma_mem->virt_base = mem_base;
dev->dma_mem->device_base = device_addr;
dev->dma_mem->size = pages;
dev->dma_mem->flags = flags;
if (flags & DMA_MEMORY_MAP)
return DMA_MEMORY_MAP;
return DMA_MEMORY_IO;
free1_out:
kfree(dev->dma_mem->bitmap);
out:
return 0;
}
EXPORT_SYMBOL(dma_declare_coherent_memory);
void dma_release_declared_memory(struct device *dev)
{
struct dma_coherent_mem *mem = dev->dma_mem;
if(!mem)
return;
dev->dma_mem = NULL;
iounmap(mem->virt_base);
kfree(mem->bitmap);
kfree(mem);
}
EXPORT_SYMBOL(dma_release_declared_memory);
void *dma_mark_declared_memory_occupied(struct device *dev,
dma_addr_t device_addr, size_t size)
{
struct dma_coherent_mem *mem = dev->dma_mem;
int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;
int pos, err;
if (!mem)
return ERR_PTR(-EINVAL);
pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
if (err != 0)
return ERR_PTR(err);
return mem->virt_base + (pos << PAGE_SHIFT);
}
EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
#endif
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