- 根目录:
- arch
- powerpc
- mm
- dma-noncoherent.c
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/highmem.h>
#include <linux/dma-mapping.h>
#include <asm/tlbflush.h>
#include "mmu_decl.h"
#define CONSISTENT_BASE (IOREMAP_TOP)
#define CONSISTENT_END (CONSISTENT_BASE + CONFIG_CONSISTENT_SIZE)
#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
static DEFINE_SPINLOCK(consistent_lock);
struct ppc_vm_region {
struct list_head vm_list;
unsigned long vm_start;
unsigned long vm_end;
};
static struct ppc_vm_region consistent_head = {
.vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
.vm_start = CONSISTENT_BASE,
.vm_end = CONSISTENT_END,
};
static struct ppc_vm_region *
ppc_vm_region_alloc(struct ppc_vm_region *head, size_t size, gfp_t gfp)
{
unsigned long addr = head->vm_start, end = head->vm_end - size;
unsigned long flags;
struct ppc_vm_region *c, *new;
new = kmalloc(sizeof(struct ppc_vm_region), gfp);
if (!new)
goto out;
spin_lock_irqsave(&consistent_lock, flags);
list_for_each_entry(c, &head->vm_list, vm_list) {
if ((addr + size) < addr)
goto nospc;
if ((addr + size) <= c->vm_start)
goto found;
addr = c->vm_end;
if (addr > end)
goto nospc;
}
found:
list_add_tail(&new->vm_list, &c->vm_list);
new->vm_start = addr;
new->vm_end = addr + size;
spin_unlock_irqrestore(&consistent_lock, flags);
return new;
nospc:
spin_unlock_irqrestore(&consistent_lock, flags);
kfree(new);
out:
return NULL;
}
static struct ppc_vm_region *ppc_vm_region_find(struct ppc_vm_region *head, unsigned long addr)
{
struct ppc_vm_region *c;
list_for_each_entry(c, &head->vm_list, vm_list) {
if (c->vm_start == addr)
goto out;
}
c = NULL;
out:
return c;
}
void *
__dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
{
struct page *page;
struct ppc_vm_region *c;
unsigned long order;
u64 mask = ISA_DMA_THRESHOLD, limit;
if (dev) {
mask = dev->coherent_dma_mask;
if (mask == 0) {
dev_warn(dev, "coherent DMA mask is unset\n");
goto no_page;
}
if ((~mask) & ISA_DMA_THRESHOLD) {
dev_warn(dev, "coherent DMA mask %#llx is smaller "
"than system GFP_DMA mask %#llx\n",
mask, (unsigned long long)ISA_DMA_THRESHOLD);
goto no_page;
}
}
size = PAGE_ALIGN(size);
limit = (mask + 1) & ~mask;
if ((limit && size >= limit) ||
size >= (CONSISTENT_END - CONSISTENT_BASE)) {
printk(KERN_WARNING "coherent allocation too big (requested %#x mask %#Lx)\n",
size, mask);
return NULL;
}
order = get_order(size);
if (mask != 0xffffffff)
gfp |= GFP_DMA;
page = alloc_pages(gfp, order);
if (!page)
goto no_page;
{
unsigned long kaddr = (unsigned long)page_address(page);
memset(page_address(page), 0, size);
flush_dcache_range(kaddr, kaddr + size);
}
c = ppc_vm_region_alloc(&consistent_head, size,
gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
if (c) {
unsigned long vaddr = c->vm_start;
struct page *end = page + (1 << order);
split_page(page, order);
*handle = page_to_phys(page);
do {
SetPageReserved(page);
map_page(vaddr, page_to_phys(page),
pgprot_noncached(PAGE_KERNEL));
page++;
vaddr += PAGE_SIZE;
} while (size -= PAGE_SIZE);
while (page < end) {
__free_page(page);
page++;
}
return (void *)c->vm_start;
}
if (page)
__free_pages(page, order);
no_page:
return NULL;
}
EXPORT_SYMBOL(__dma_alloc_coherent);
void __dma_free_coherent(size_t size, void *vaddr)
{
struct ppc_vm_region *c;
unsigned long flags, addr;
size = PAGE_ALIGN(size);
spin_lock_irqsave(&consistent_lock, flags);
c = ppc_vm_region_find(&consistent_head, (unsigned long)vaddr);
if (!c)
goto no_area;
if ((c->vm_end - c->vm_start) != size) {
printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
__func__, c->vm_end - c->vm_start, size);
dump_stack();
size = c->vm_end - c->vm_start;
}
addr = c->vm_start;
do {
pte_t *ptep;
unsigned long pfn;
ptep = pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(addr),
addr),
addr),
addr);
if (!pte_none(*ptep) && pte_present(*ptep)) {
pfn = pte_pfn(*ptep);
pte_clear(&init_mm, addr, ptep);
if (pfn_valid(pfn)) {
struct page *page = pfn_to_page(pfn);
ClearPageReserved(page);
__free_page(page);
}
}
addr += PAGE_SIZE;
} while (size -= PAGE_SIZE);
flush_tlb_kernel_range(c->vm_start, c->vm_end);
list_del(&c->vm_list);
spin_unlock_irqrestore(&consistent_lock, flags);
kfree(c);
return;
no_area:
spin_unlock_irqrestore(&consistent_lock, flags);
printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
__func__, vaddr);
dump_stack();
}
EXPORT_SYMBOL(__dma_free_coherent);
void __dma_sync(void *vaddr, size_t size, int direction)
{
unsigned long start = (unsigned long)vaddr;
unsigned long end = start + size;
switch (direction) {
case DMA_NONE:
BUG();
case DMA_FROM_DEVICE:
if ((start & (L1_CACHE_BYTES - 1)) || (size & (L1_CACHE_BYTES - 1)))
flush_dcache_range(start, end);
else
invalidate_dcache_range(start, end);
break;
case DMA_TO_DEVICE:
clean_dcache_range(start, end);
break;
case DMA_BIDIRECTIONAL:
flush_dcache_range(start, end);
break;
}
}
EXPORT_SYMBOL(__dma_sync);
#ifdef CONFIG_HIGHMEM
static inline void __dma_sync_page_highmem(struct page *page,
unsigned long offset, size_t size, int direction)
{
size_t seg_size = min((size_t)(PAGE_SIZE - offset), size);
size_t cur_size = seg_size;
unsigned long flags, start, seg_offset = offset;
int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE;
int seg_nr = 0;
local_irq_save(flags);
do {
start = (unsigned long)kmap_atomic(page + seg_nr,
KM_PPC_SYNC_PAGE) + seg_offset;
__dma_sync((void *)start, seg_size, direction);
kunmap_atomic((void *)start, KM_PPC_SYNC_PAGE);
seg_nr++;
seg_size = min((size_t)PAGE_SIZE, size - cur_size);
cur_size += seg_size;
seg_offset = 0;
} while (seg_nr < nr_segs);
local_irq_restore(flags);
}
#endif
void __dma_sync_page(struct page *page, unsigned long offset,
size_t size, int direction)
{
#ifdef CONFIG_HIGHMEM
__dma_sync_page_highmem(page, offset, size, direction);
#else
unsigned long start = (unsigned long)page_address(page) + offset;
__dma_sync((void *)start, size, direction);
#endif
}
EXPORT_SYMBOL(__dma_sync_page);
unsigned long __dma_get_coherent_pfn(unsigned long cpu_addr)
{
pgd_t *pgd = pgd_offset_k(cpu_addr);
pud_t *pud = pud_offset(pgd, cpu_addr);
pmd_t *pmd = pmd_offset(pud, cpu_addr);
pte_t *ptep = pte_offset_kernel(pmd, cpu_addr);
if (pte_none(*ptep) || !pte_present(*ptep))
return 0;
return pte_pfn(*ptep);
}
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