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-rw-r--r--arch/arm/mm/consistent.c451
1 files changed, 451 insertions, 0 deletions
diff --git a/arch/arm/mm/consistent.c b/arch/arm/mm/consistent.c
new file mode 100644
index 00000000000..26356ce4da5
--- /dev/null
+++ b/arch/arm/mm/consistent.c
@@ -0,0 +1,451 @@
+/*
+ * linux/arch/arm/mm/consistent.c
+ *
+ * Copyright (C) 2000-2004 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * DMA uncached mapping support.
+ */
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/cacheflush.h>
+#include <asm/io.h>
+#include <asm/tlbflush.h>
+
+#define CONSISTENT_BASE (0xffc00000)
+#define CONSISTENT_END (0xffe00000)
+#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;
+ struct page *vm_pages;
+};
+
+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, int 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;
+}
+
+#ifdef CONFIG_HUGETLB_PAGE
+#error ARM Coherent DMA allocator does not (yet) support huge TLB
+#endif
+
+static void *
+__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, int gfp,
+ pgprot_t prot)
+{
+ struct page *page;
+ struct vm_region *c;
+ unsigned long order;
+ u64 mask = ISA_DMA_THRESHOLD, limit;
+
+ if (!consistent_pte) {
+ printk(KERN_ERR "%s: not initialised\n", __func__);
+ dump_stack();
+ return NULL;
+ }
+
+ if (dev) {
+ mask = dev->coherent_dma_mask;
+
+ /*
+ * Sanity check the DMA mask - it must be non-zero, and
+ * must be able to be satisfied by a DMA allocation.
+ */
+ 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;
+ }
+ }
+
+ /*
+ * Sanity check the allocation size.
+ */
+ 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 %#llx)\n", size, mask);
+ goto no_page;
+ }
+
+ order = get_order(size);
+
+ if (mask != 0xffffffff)
+ gfp |= GFP_DMA;
+
+ page = alloc_pages(gfp, order);
+ if (!page)
+ goto no_page;
+
+ /*
+ * 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);
+ dmac_flush_range(kaddr, kaddr + size);
+ }
+
+ /*
+ * Allocate a virtual address in the consistent mapping region.
+ */
+ c = vm_region_alloc(&consistent_head, size,
+ gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
+ if (c) {
+ pte_t *pte = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
+ struct page *end = page + (1 << order);
+
+ c->vm_pages = page;
+
+ /*
+ * Set the "dma handle"
+ */
+ *handle = page_to_dma(dev, page);
+
+ do {
+ BUG_ON(!pte_none(*pte));
+
+ set_page_count(page, 1);
+ /*
+ * x86 does not mark the pages reserved...
+ */
+ SetPageReserved(page);
+ set_pte(pte, mk_pte(page, prot));
+ page++;
+ pte++;
+ } while (size -= PAGE_SIZE);
+
+ /*
+ * Free the otherwise unused pages.
+ */
+ while (page < end) {
+ set_page_count(page, 1);
+ __free_page(page);
+ page++;
+ }
+
+ return (void *)c->vm_start;
+ }
+
+ if (page)
+ __free_pages(page, order);
+ no_page:
+ *handle = ~0;
+ return NULL;
+}
+
+/*
+ * Allocate DMA-coherent memory space and return both the kernel remapped
+ * virtual and bus address for that space.
+ */
+void *
+dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, int gfp)
+{
+ return __dma_alloc(dev, size, handle, gfp,
+ pgprot_noncached(pgprot_kernel));
+}
+EXPORT_SYMBOL(dma_alloc_coherent);
+
+/*
+ * Allocate a writecombining region, in much the same way as
+ * dma_alloc_coherent above.
+ */
+void *
+dma_alloc_writecombine(struct device *dev, size_t size, dma_addr_t *handle, int gfp)
+{
+ return __dma_alloc(dev, size, handle, gfp,
+ pgprot_writecombine(pgprot_kernel));
+}
+EXPORT_SYMBOL(dma_alloc_writecombine);
+
+static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
+ void *cpu_addr, dma_addr_t dma_addr, size_t size)
+{
+ unsigned long flags, user_size, kern_size;
+ struct vm_region *c;
+ int ret = -ENXIO;
+
+ user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+
+ spin_lock_irqsave(&consistent_lock, flags);
+ c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
+ spin_unlock_irqrestore(&consistent_lock, flags);
+
+ if (c) {
+ unsigned long off = vma->vm_pgoff;
+
+ kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
+
+ if (off < kern_size &&
+ user_size <= (kern_size - off)) {
+ vma->vm_flags |= VM_RESERVED;
+ ret = remap_pfn_range(vma, vma->vm_start,
+ page_to_pfn(c->vm_pages) + off,
+ user_size << PAGE_SHIFT,
+ vma->vm_page_prot);
+ }
+ }
+
+ return ret;
+}
+
+int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
+ void *cpu_addr, dma_addr_t dma_addr, size_t size)
+{
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+ return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
+}
+EXPORT_SYMBOL(dma_mmap_coherent);
+
+int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
+ void *cpu_addr, dma_addr_t dma_addr, size_t size)
+{
+ vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+ return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
+}
+EXPORT_SYMBOL(dma_mmap_writecombine);
+
+/*
+ * free a page as defined by the above mapping.
+ */
+void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
+{
+ struct vm_region *c;
+ unsigned long flags, addr;
+ pte_t *ptep;
+
+ size = PAGE_ALIGN(size);
+
+ spin_lock_irqsave(&consistent_lock, flags);
+
+ c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
+ 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);
+
+ /*
+ * x86 does not mark the pages reserved...
+ */
+ 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__, cpu_addr);
+ dump_stack();
+}
+EXPORT_SYMBOL(dma_free_coherent);
+
+/*
+ * Initialise the consistent memory allocation.
+ */
+static int __init consistent_init(void)
+{
+ pgd_t *pgd;
+ pmd_t *pmd;
+ pte_t *pte;
+ int ret = 0;
+
+ spin_lock(&init_mm.page_table_lock);
+
+ do {
+ pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
+ pmd = pmd_alloc(&init_mm, pgd, 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(&init_mm, pmd, CONSISTENT_BASE);
+ if (!pte) {
+ printk(KERN_ERR "%s: no pte tables\n", __func__);
+ ret = -ENOMEM;
+ break;
+ }
+
+ consistent_pte = pte;
+ } while (0);
+
+ spin_unlock(&init_mm.page_table_lock);
+
+ return ret;
+}
+
+core_initcall(consistent_init);
+
+/*
+ * Make an area consistent for devices.
+ */
+void consistent_sync(void *vaddr, size_t size, int direction)
+{
+ unsigned long start = (unsigned long)vaddr;
+ unsigned long end = start + size;
+
+ switch (direction) {
+ case DMA_FROM_DEVICE: /* invalidate only */
+ dmac_inv_range(start, end);
+ break;
+ case DMA_TO_DEVICE: /* writeback only */
+ dmac_clean_range(start, end);
+ break;
+ case DMA_BIDIRECTIONAL: /* writeback and invalidate */
+ dmac_flush_range(start, end);
+ break;
+ default:
+ BUG();
+ }
+}
+EXPORT_SYMBOL(consistent_sync);
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