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powerpc: Rework dma-noncoherent to use generic vmalloc layer
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>
This commit is contained in:
Ilya Yanok
committed by
Benjamin Herrenschmidt
Benjamin Herrenschmidt
parent
812d904e39
commit
33f00dcedb
@@ -29,120 +29,10 @@
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#include <linux/types.h>
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#include <linux/highmem.h>
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#include <linux/dma-mapping.h>
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#include <linux/vmalloc.h>
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#include <asm/tlbflush.h>
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/*
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* This address range defaults to a value that is safe for all
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* platforms which currently set CONFIG_NOT_COHERENT_CACHE. It
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* can be further configured for specific applications under
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* the "Advanced Setup" menu. -Matt
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*/
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#define CONSISTENT_BASE (CONFIG_CONSISTENT_START)
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#define CONSISTENT_END (CONFIG_CONSISTENT_START + CONFIG_CONSISTENT_SIZE)
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#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
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/*
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* This is the page table (2MB) covering uncached, DMA consistent allocations
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*/
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static pte_t *consistent_pte;
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static DEFINE_SPINLOCK(consistent_lock);
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/*
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* VM region handling support.
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*
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* This should become something generic, handling VM region allocations for
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* vmalloc and similar (ioremap, module space, etc).
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*
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* I envisage vmalloc()'s supporting vm_struct becoming:
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*
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* struct vm_struct {
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* struct vm_region region;
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* unsigned long flags;
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* struct page **pages;
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* unsigned int nr_pages;
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* unsigned long phys_addr;
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* };
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*
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* get_vm_area() would then call vm_region_alloc with an appropriate
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* struct vm_region head (eg):
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*
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* struct vm_region vmalloc_head = {
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* .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list),
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* .vm_start = VMALLOC_START,
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* .vm_end = VMALLOC_END,
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* };
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*
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* However, vmalloc_head.vm_start is variable (typically, it is dependent on
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* the amount of RAM found at boot time.) I would imagine that get_vm_area()
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* would have to initialise this each time prior to calling vm_region_alloc().
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*/
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struct ppc_vm_region {
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struct list_head vm_list;
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unsigned long vm_start;
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unsigned long vm_end;
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};
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static struct ppc_vm_region consistent_head = {
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.vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
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.vm_start = CONSISTENT_BASE,
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.vm_end = CONSISTENT_END,
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};
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static struct ppc_vm_region *
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ppc_vm_region_alloc(struct ppc_vm_region *head, size_t size, gfp_t gfp)
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{
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unsigned long addr = head->vm_start, end = head->vm_end - size;
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unsigned long flags;
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struct ppc_vm_region *c, *new;
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new = kmalloc(sizeof(struct ppc_vm_region), gfp);
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if (!new)
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goto out;
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spin_lock_irqsave(&consistent_lock, flags);
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list_for_each_entry(c, &head->vm_list, vm_list) {
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if ((addr + size) < addr)
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goto nospc;
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if ((addr + size) <= c->vm_start)
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goto found;
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addr = c->vm_end;
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if (addr > end)
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goto nospc;
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}
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found:
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/*
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* Insert this entry _before_ the one we found.
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*/
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list_add_tail(&new->vm_list, &c->vm_list);
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new->vm_start = addr;
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new->vm_end = addr + size;
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spin_unlock_irqrestore(&consistent_lock, flags);
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return new;
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nospc:
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spin_unlock_irqrestore(&consistent_lock, flags);
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kfree(new);
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out:
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return NULL;
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}
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static struct ppc_vm_region *ppc_vm_region_find(struct ppc_vm_region *head, unsigned long addr)
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{
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struct ppc_vm_region *c;
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list_for_each_entry(c, &head->vm_list, vm_list) {
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if (c->vm_start == addr)
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goto out;
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}
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c = NULL;
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out:
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return c;
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}
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/*
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* Allocate DMA-coherent memory space and return both the kernel remapped
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* virtual and bus address for that space.
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@@ -151,21 +41,21 @@ void *
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__dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
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{
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struct page *page;
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struct ppc_vm_region *c;
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unsigned long order;
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int i;
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unsigned int nr_pages = PAGE_ALIGN(size)>>PAGE_SHIFT;
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unsigned int array_size = nr_pages * sizeof(struct page *);
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struct page **pages;
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struct page *end;
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u64 mask = 0x00ffffff, limit; /* ISA default */
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struct vm_struct *area;
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if (!consistent_pte) {
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printk(KERN_ERR "%s: not initialised\n", __func__);
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dump_stack();
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return NULL;
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}
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BUG_ON(!mem_init_done);
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size = PAGE_ALIGN(size);
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limit = (mask + 1) & ~mask;
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if ((limit && size >= limit) || size >= (CONSISTENT_END - CONSISTENT_BASE)) {
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printk(KERN_WARNING "coherent allocation too big (requested %#x mask %#Lx)\n",
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size, mask);
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if (limit && size >= limit) {
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printk(KERN_WARNING "coherent allocation too big (requested "
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"%#x mask %#Lx)\n", size, mask);
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return NULL;
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}
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@@ -178,6 +68,8 @@ __dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
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if (!page)
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goto no_page;
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end = page + (1 << order);
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/*
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* Invalidate any data that might be lurking in the
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* kernel direct-mapped region for device DMA.
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@@ -188,48 +80,59 @@ __dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
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flush_dcache_range(kaddr, kaddr + size);
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}
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split_page(page, order);
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/*
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* Allocate a virtual address in the consistent mapping region.
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* Set the "dma handle"
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*/
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c = ppc_vm_region_alloc(&consistent_head, size,
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gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
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if (c) {
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unsigned long vaddr = c->vm_start;
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pte_t *pte = consistent_pte + CONSISTENT_OFFSET(vaddr);
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struct page *end = page + (1 << order);
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*handle = page_to_phys(page);
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split_page(page, order);
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area = get_vm_area_caller(size, VM_IOREMAP,
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__builtin_return_address(1));
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if (!area)
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goto out_free_pages;
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/*
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* Set the "dma handle"
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*/
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*handle = page_to_phys(page);
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if (array_size > PAGE_SIZE) {
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pages = vmalloc(array_size);
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area->flags |= VM_VPAGES;
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} else {
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pages = kmalloc(array_size, GFP_KERNEL);
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}
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if (!pages)
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goto out_free_area;
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do {
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BUG_ON(!pte_none(*pte));
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area->pages = pages;
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area->nr_pages = nr_pages;
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SetPageReserved(page);
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set_pte_at(&init_mm, vaddr,
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pte, mk_pte(page, pgprot_noncached(PAGE_KERNEL)));
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page++;
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pte++;
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vaddr += PAGE_SIZE;
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} while (size -= PAGE_SIZE);
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for (i = 0; i < nr_pages; i++)
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pages[i] = page + i;
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/*
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* Free the otherwise unused pages.
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*/
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while (page < end) {
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__free_page(page);
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page++;
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}
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if (map_vm_area(area, pgprot_noncached(PAGE_KERNEL), &pages))
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goto out_unmap;
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return (void *)c->vm_start;
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/*
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* Free the otherwise unused pages.
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*/
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page += nr_pages;
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while (page < end) {
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__free_page(page);
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page++;
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}
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return area->addr;
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out_unmap:
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vunmap(area->addr);
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if (array_size > PAGE_SIZE)
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vfree(pages);
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else
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kfree(pages);
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goto out_free_pages;
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out_free_area:
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free_vm_area(area);
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out_free_pages:
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if (page)
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__free_pages(page, order);
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no_page:
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no_page:
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return NULL;
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}
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EXPORT_SYMBOL(__dma_alloc_coherent);
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@@ -239,103 +142,11 @@ EXPORT_SYMBOL(__dma_alloc_coherent);
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*/
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void __dma_free_coherent(size_t size, void *vaddr)
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{
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struct ppc_vm_region *c;
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unsigned long flags, addr;
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pte_t *ptep;
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vfree(vaddr);
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size = PAGE_ALIGN(size);
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spin_lock_irqsave(&consistent_lock, flags);
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c = ppc_vm_region_find(&consistent_head, (unsigned long)vaddr);
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if (!c)
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goto no_area;
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if ((c->vm_end - c->vm_start) != size) {
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printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
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__func__, c->vm_end - c->vm_start, size);
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dump_stack();
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size = c->vm_end - c->vm_start;
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}
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ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
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addr = c->vm_start;
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do {
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pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
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unsigned long pfn;
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ptep++;
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addr += PAGE_SIZE;
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if (!pte_none(pte) && pte_present(pte)) {
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pfn = pte_pfn(pte);
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if (pfn_valid(pfn)) {
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struct page *page = pfn_to_page(pfn);
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ClearPageReserved(page);
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__free_page(page);
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continue;
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}
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}
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printk(KERN_CRIT "%s: bad page in kernel page table\n",
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__func__);
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} while (size -= PAGE_SIZE);
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flush_tlb_kernel_range(c->vm_start, c->vm_end);
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list_del(&c->vm_list);
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spin_unlock_irqrestore(&consistent_lock, flags);
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kfree(c);
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return;
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no_area:
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spin_unlock_irqrestore(&consistent_lock, flags);
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printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
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__func__, vaddr);
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dump_stack();
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}
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EXPORT_SYMBOL(__dma_free_coherent);
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/*
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* Initialise the consistent memory allocation.
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*/
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static int __init dma_alloc_init(void)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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int ret = 0;
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do {
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pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
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pud = pud_alloc(&init_mm, pgd, CONSISTENT_BASE);
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pmd = pmd_alloc(&init_mm, pud, CONSISTENT_BASE);
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if (!pmd) {
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printk(KERN_ERR "%s: no pmd tables\n", __func__);
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ret = -ENOMEM;
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break;
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}
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pte = pte_alloc_kernel(pmd, CONSISTENT_BASE);
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if (!pte) {
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printk(KERN_ERR "%s: no pte tables\n", __func__);
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ret = -ENOMEM;
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break;
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}
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consistent_pte = pte;
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} while (0);
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return ret;
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}
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core_initcall(dma_alloc_init);
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/*
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* make an area consistent.
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*/
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