powerpc: Rework dma-noncoherent to use generic vmalloc layer
authorIlya Yanok <yanok@emcraft.com>
Thu, 12 Feb 2009 13:20:53 +0000 (13:20 +0000)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>
Sun, 22 Feb 2009 23:48:57 +0000 (10:48 +1100)
This patch rewrites consistent dma allocations support to use vmalloc
layer to allocate virtual memory space from vmalloc pool and get rid
of CONFIG_CONSISTENT_{START,SIZE}.

This greatly simplifies the code by effectively removing a custom
allocator we had for virtual space.

Signed-off-by: Ilya Yanok <yanok@emcraft.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
arch/powerpc/Kconfig
arch/powerpc/lib/dma-noncoherent.c

index e46995a216853cb339f15a61084356dce4a4a421..d11896b445b6a2459b7559008c3901cc0bd37d33 100644 (file)
@@ -833,31 +833,6 @@ config TASK_SIZE
        default "0x80000000" if PPC_PREP || PPC_8xx
        default "0xc0000000"
 
-config CONSISTENT_START_BOOL
-       bool "Set custom consistent memory pool address"
-       depends on ADVANCED_OPTIONS && NOT_COHERENT_CACHE
-       help
-         This option allows you to set the base virtual address
-         of the consistent memory pool.  This pool of virtual
-         memory is used to make consistent memory allocations.
-
-config CONSISTENT_START
-       hex "Base virtual address of consistent memory pool" if CONSISTENT_START_BOOL
-       default "0xfd000000" if (NOT_COHERENT_CACHE && 8xx)
-       default "0xff100000" if NOT_COHERENT_CACHE
-
-config CONSISTENT_SIZE_BOOL
-       bool "Set custom consistent memory pool size"
-       depends on ADVANCED_OPTIONS && NOT_COHERENT_CACHE
-       help
-         This option allows you to set the size of the
-         consistent memory pool.  This pool of virtual memory
-         is used to make consistent memory allocations.
-
-config CONSISTENT_SIZE
-       hex "Size of consistent memory pool" if CONSISTENT_SIZE_BOOL
-       default "0x00200000" if NOT_COHERENT_CACHE
-
 config PIN_TLB
        bool "Pinned Kernel TLBs (860 ONLY)"
        depends on ADVANCED_OPTIONS && 8xx
index b7dc4c19f58211641d2bb1db44dea62315a3d641..005a28d380af9c94528437d7f6c0940c08085744 100644 (file)
 #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.
@@ -151,21 +41,21 @@ void *
 __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;
 
-       if (!consistent_pte) {
-               printk(KERN_ERR "%s: not initialised\n", __func__);
-               dump_stack();
-               return NULL;
-       }
-
+       BUG_ON(!mem_init_done);
        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;
        }
 
@@ -178,6 +68,8 @@ __dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
        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.
@@ -188,48 +80,59 @@ __dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
                flush_dcache_range(kaddr, kaddr + size);
        }
 
+       split_page(page, order);
+
        /*
-        * Allocate a virtual address in the consistent mapping region.
+        * Set the "dma handle"
         */
-       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);
-
-               split_page(page, order);
-
-               /*
-                * Set the "dma handle"
-                */
-               *handle = page_to_phys(page);
+       *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;
 
-               do {
-                       BUG_ON(!pte_none(*pte));
+       area->pages = pages;
+       area->nr_pages = nr_pages;
 
-                       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);
+       for (i = 0; i < nr_pages; i++)
+               pages[i] = page + i;
 
-               /*
-                * Free the otherwise unused pages.
-                */
-               while (page < end) {
-                       __free_page(page);
-                       page++;
-               }
+       if (map_vm_area(area, pgprot_noncached(PAGE_KERNEL), &pages))
+               goto out_unmap;
 
-               return (void *)c->vm_start;
+       /*
+        * Free the otherwise unused pages.
+        */
+       page += nr_pages;
+       while (page < end) {
+               __free_page(page);
+               page++;
        }
 
+       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);
@@ -239,103 +142,11 @@ EXPORT_SYMBOL(__dma_alloc_coherent);
  */
 void __dma_free_coherent(size_t size, void *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;
+       vfree(vaddr);
 
-               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.
  */