@@ -29,143 +29,28 @@
#include <linux/types.h>
#include <linux/highmem.h>
#include <linux/dma-mapping.h>
+#include <linux/vmalloc.h>
#include <asm/tlbflush.h>
/*
- * This address range defaults to a value that is safe for all
- * platforms which currently set CONFIG_NOT_COHERENT_CACHE. It
- * can be further configured for specific applications under
- * the "Advanced Setup" menu. -Matt
- */
-#define CONSISTENT_BASE (CONFIG_CONSISTENT_START)
-#define CONSISTENT_END (CONFIG_CONSISTENT_START + CONFIG_CONSISTENT_SIZE)
-#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
-
-/*
- * This is the page table (2MB) covering uncached, DMA consistent allocations
- */
-static pte_t *consistent_pte;
-static DEFINE_SPINLOCK(consistent_lock);
-
-/*
- * VM region handling support.
- *
- * This should become something generic, handling VM region allocations for
- * vmalloc and similar (ioremap, module space, etc).
- *
- * I envisage vmalloc()'s supporting vm_struct becoming:
- *
- * struct vm_struct {
- * struct vm_region region;
- * unsigned long flags;
- * struct page **pages;
- * unsigned int nr_pages;
- * unsigned long phys_addr;
- * };
- *
- * get_vm_area() would then call vm_region_alloc with an appropriate
- * struct vm_region head (eg):
- *
- * struct vm_region vmalloc_head = {
- * .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list),
- * .vm_start = VMALLOC_START,
- * .vm_end = VMALLOC_END,
- * };
- *
- * However, vmalloc_head.vm_start is variable (typically, it is dependent on
- * the amount of RAM found at boot time.) I would imagine that get_vm_area()
- * would have to initialise this each time prior to calling vm_region_alloc().
- */
-struct vm_region {
- struct list_head vm_list;
- unsigned long vm_start;
- unsigned long vm_end;
-};
-
-static struct vm_region consistent_head = {
- .vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
- .vm_start = CONSISTENT_BASE,
- .vm_end = CONSISTENT_END,
-};
-
-static struct vm_region *
-vm_region_alloc(struct vm_region *head, size_t size, gfp_t gfp)
-{
- unsigned long addr = head->vm_start, end = head->vm_end - size;
- unsigned long flags;
- struct vm_region *c, *new;
-
- new = kmalloc(sizeof(struct 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:
- /*
- * Insert this entry _before_ the one we 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 vm_region *vm_region_find(struct vm_region *head, unsigned long addr)
-{
- struct 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;
-}
-
-/*
* Allocate DMA-coherent memory space and return both the kernel remapped
* virtual and bus address for that space.
*/
void *
__dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
{
- struct page *page;
- struct vm_region *c;
+ struct page *page, *p;
unsigned long order;
+ unsigned long kaddr;
+ unsigned long addr;
u64 mask = 0x00ffffff, limit; /* ISA default */
- if (!consistent_pte) {
- printk(KERN_ERR "%s: not initialised\n", __func__);
- dump_stack();
- return NULL;
- }
-
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);
+ if (limit && size >= limit) {
+ printk(KERN_WARNING "coherent allocation too big " \
+ "(requested %#x mask %#Lx)\n", size, mask);
return NULL;
}
@@ -176,61 +61,47 @@ __dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
page = alloc_pages(gfp, order);
if (!page)
- goto no_page;
+ return NULL;
/*
* Invalidate any data that might be lurking in the
* kernel direct-mapped region for device DMA.
*/
- {
- unsigned long kaddr = (unsigned long)page_address(page);
- memset(page_address(page), 0, size);
- flush_dcache_range(kaddr, kaddr + size);
- }
+ kaddr = (unsigned long)page_address(page);
+ BUG_ON(kaddr == 0);
+ /* the name is confusing here: flush_dcache_range does a
+ flush + invalidate */
+ flush_dcache_range(kaddr, kaddr + size);
/*
- * Allocate a virtual address in the consistent mapping region.
+ * Out of the returned page generate a table of 1<<order
+ * PAGE_SIZE pages. This make sure each page has its own PTE.
*/
- c = vm_region_alloc(&consistent_head, size,
- gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
- if (c) {
- unsigned long vaddr = c->vm_start;
- pte_t *pte = consistent_pte + CONSISTENT_OFFSET(vaddr);
- struct page *end = page + (1 << order);
-
- split_page(page, order);
-
- /*
- * Set the "dma handle"
- */
- *handle = page_to_bus(page);
-
- do {
- BUG_ON(!pte_none(*pte));
-
- SetPageReserved(page);
- set_pte_at(&init_mm, vaddr,
- pte, mk_pte(page, pgprot_noncached(PAGE_KERNEL)));
- page++;
- pte++;
- vaddr += PAGE_SIZE;
- } while (size -= PAGE_SIZE);
-
- /*
- * Free the otherwise unused pages.
- */
- while (page < end) {
- __free_page(page);
- page++;
- }
+ split_page(page, order);
- return (void *)c->vm_start;
+ /*
+ * Mark the pages as Reserved: this memory is used by a DMA engine,
+ * it cannot be swapped.
+ * Also mark each page as un-cached. We ass ume here that a PTE
+ * already exist (valid assumption for the DMA Zone)
+ */
+ for (addr = kaddr, p = page; addr < kaddr+size;
+ addr += PAGE_SIZE, p++) {
+ pte_t *pte;
+ spinlock_t *ptl;
+
+ SetPageReserved(p);
+ pte = get_locked_pte(&init_mm, addr, &ptl);
+ set_pte_at(&init_mm, addr,
+ pte, mk_pte(p, pgprot_noncached(PAGE_KERNEL)));
+ pte_unmap_unlock(pte, ptl);
}
+ flush_tlb_kernel_range(kaddr, kaddr+size-1);
- if (page)
- __free_pages(page, order);
- no_page:
- return NULL;
+ /* Handle is the physical address of the first page */
+ *handle = page_to_bus(page);
+
+ return (void *)kaddr;
}
EXPORT_SYMBOL(__dma_alloc_coherent);
@@ -238,125 +109,62 @@ EXPORT_SYMBOL(__dma_alloc_coherent);
* free a page as defined by the above mapping.
*/
void __dma_free_coherent(size_t size, void *vaddr)
-{
- struct vm_region *c;
- unsigned long flags, addr;
- pte_t *ptep;
+{ struct page *page;
+ unsigned long order;
+ unsigned long addr;
+ /* This is safe because we do the same in __dma_alloc_coherent */
size = PAGE_ALIGN(size);
+ order = get_order(size);
- spin_lock_irqsave(&consistent_lock, flags);
-
- c = 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;
+ /* Retrieve the page associated with this address */
+ page = virt_to_page(vaddr);
+ BUG_ON(page == NULL);
+
+ /* Release the physical memory */
+ for (addr = (unsigned long)vaddr; addr < (unsigned long)vaddr+size;
+ addr += PAGE_SIZE, page++) {
+ pte_t *pte;
+ spinlock_t *ptl;
+
+ ClearPageReserved(page);
+ pte = get_locked_pte(&init_mm, addr, &ptl);
+ set_pte_at(&init_mm, addr, pte, mk_pte(page, PAGE_KERNEL));
+ pte_unmap_unlock(pte, ptl);
+ __free_page(page);
}
-
- ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
- addr = c->vm_start;
- do {
- pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
- unsigned long pfn;
-
- ptep++;
- addr += PAGE_SIZE;
-
- if (!pte_none(pte) && pte_present(pte)) {
- pfn = pte_pfn(pte);
-
- if (pfn_valid(pfn)) {
- struct page *page = pfn_to_page(pfn);
- ClearPageReserved(page);
-
- __free_page(page);
- continue;
- }
- }
-
- printk(KERN_CRIT "%s: bad page in kernel page table\n",
- __func__);
- } 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);
/*
- * Initialise the consistent memory allocation.
- */
-static int __init dma_alloc_init(void)
-{
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
- int ret = 0;
-
- do {
- pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
- pud = pud_alloc(&init_mm, pgd, CONSISTENT_BASE);
- pmd = pmd_alloc(&init_mm, pud, CONSISTENT_BASE);
- if (!pmd) {
- printk(KERN_ERR "%s: no pmd tables\n", __func__);
- ret = -ENOMEM;
- break;
- }
- WARN_ON(!pmd_none(*pmd));
-
- pte = pte_alloc_kernel(pmd, CONSISTENT_BASE);
- if (!pte) {
- printk(KERN_ERR "%s: no pte tables\n", __func__);
- ret = -ENOMEM;
- break;
- }
-
- consistent_pte = pte;
- } while (0);
-
- return ret;
-}
-
-core_initcall(dma_alloc_init);
-
-/*
* make an area consistent.
*/
void __dma_sync(void *vaddr, size_t size, int direction)
{
unsigned long start = (unsigned long)vaddr;
unsigned long end = start + size;
+ int unaligned;
switch (direction) {
case DMA_NONE:
BUG();
case DMA_FROM_DEVICE:
/*
- * invalidate only when cache-line aligned otherwise there is
- * the potential for discarding uncommitted data from the cache
+ * if start or size is not cache aligned we flush before
+ * invalidating.
+ * Beware: flush_dcache_range does flush and invalidate
*/
- if ((start & (L1_CACHE_BYTES - 1)) || (size & (L1_CACHE_BYTES - 1)))
- flush_dcache_range(start, end);
- else
- invalidate_dcache_range(start, end);
+ unaligned = start & (L1_CACHE_BYTES - 1);
+ if (unaligned) {
+ flush_dcache_range(start, start + L1_CACHE_BYTES);
+ start += L1_CACHE_BYTES - unaligned;
+ }
+ unaligned = end & (L1_CACHE_BYTES - 1);
+ if (unaligned) {
+ end -= unaligned;
+ flush_dcache_range(end, end + L1_CACHE_BYTES);
+ }
+ invalidate_dcache_range(start, end);
break;
case DMA_TO_DEVICE: /* writeback only */
clean_dcache_range(start, end);
@@ -368,48 +176,6 @@ void __dma_sync(void *vaddr, size_t size, int direction)
}
EXPORT_SYMBOL(__dma_sync);
-#ifdef CONFIG_HIGHMEM
-/*
- * __dma_sync_page() implementation for systems using highmem.
- * In this case, each page of a buffer must be kmapped/kunmapped
- * in order to have a virtual address for __dma_sync(). This must
- * not sleep so kmap_atomic()/kunmap_atomic() are used.
- *
- * Note: yes, it is possible and correct to have a buffer extend
- * beyond the first page.
- */
-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;
-
- /* Sync this buffer segment */
- __dma_sync((void *)start, seg_size, direction);
- kunmap_atomic((void *)start, KM_PPC_SYNC_PAGE);
- seg_nr++;
-
- /* Calculate next buffer segment size */
- seg_size = min((size_t)PAGE_SIZE, size - cur_size);
-
- /* Add the segment size to our running total */
- cur_size += seg_size;
- seg_offset = 0;
- } while (seg_nr < nr_segs);
-
- local_irq_restore(flags);
-}
-#endif /* CONFIG_HIGHMEM */
-
/*
* __dma_sync_page makes memory consistent. identical to __dma_sync, but
* takes a struct page instead of a virtual address
@@ -417,11 +183,7 @@ static inline void __dma_sync_page_highmem(struct page *page,
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);