#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 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:
+ /*
+ * 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 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;
+}
+
/*
* Allocate DMA-coherent memory space and return both the kernel remapped
* virtual and bus address for that space.
__dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
{
struct page *page;
+ struct ppc_vm_region *c;
unsigned long order;
- int i;
- unsigned int nr_pages = PAGE_ALIGN(size)>>PAGE_SHIFT;
- unsigned int array_size = nr_pages * sizeof(struct page *);
- struct page **pages;
- struct page *end;
u64 mask = 0x00ffffff, limit; /* ISA default */
- struct vm_struct *area;
- BUG_ON(!mem_init_done);
+ 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) {
- printk(KERN_WARNING "coherent allocation too big (requested "
- "%#x mask %#Lx)\n", size, 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;
}
if (!page)
goto no_page;
- end = page + (1 << order);
-
/*
* Invalidate any data that might be lurking in the
* kernel direct-mapped region for device DMA.
flush_dcache_range(kaddr, kaddr + size);
}
- split_page(page, order);
-
/*
- * Set the "dma handle"
+ * Allocate a virtual address in the consistent mapping region.
*/
- *handle = page_to_phys(page);
-
- area = get_vm_area_caller(size, VM_IOREMAP,
- __builtin_return_address(1));
- if (!area)
- goto out_free_pages;
-
- if (array_size > PAGE_SIZE) {
- pages = vmalloc(array_size);
- area->flags |= VM_VPAGES;
- } else {
- pages = kmalloc(array_size, GFP_KERNEL);
- }
- if (!pages)
- goto out_free_area;
+ c = ppc_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);
- area->pages = pages;
- area->nr_pages = nr_pages;
+ split_page(page, order);
- for (i = 0; i < nr_pages; i++)
- pages[i] = page + i;
+ /*
+ * Set the "dma handle"
+ */
+ *handle = page_to_phys(page);
- if (map_vm_area(area, pgprot_noncached(PAGE_KERNEL), &pages))
- goto out_unmap;
+ do {
+ BUG_ON(!pte_none(*pte));
- /*
- * Free the otherwise unused pages.
- */
- page += nr_pages;
- while (page < end) {
- __free_page(page);
- page++;
+ 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++;
+ }
+
+ return (void *)c->vm_start;
}
- return area->addr;
-out_unmap:
- vunmap(area->addr);
- if (array_size > PAGE_SIZE)
- vfree(pages);
- else
- kfree(pages);
- goto out_free_pages;
-out_free_area:
- free_vm_area(area);
-out_free_pages:
if (page)
__free_pages(page, order);
-no_page:
+ no_page:
return NULL;
}
EXPORT_SYMBOL(__dma_alloc_coherent);
*/
void __dma_free_coherent(size_t size, void *vaddr)
{
- vfree(vaddr);
+ struct ppc_vm_region *c;
+ unsigned long flags, addr;
+ pte_t *ptep;
+
+ 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;
+ }
+
+ 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;
+ }
+
+ 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.
*/
projects / users / hch / configfs.git / commitdiff