421 lines
10 KiB
C
421 lines
10 KiB
C
/*
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* PowerPC version derived from arch/arm/mm/consistent.c
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* Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
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*
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* Copyright (C) 2000 Russell King
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*
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* Consistent memory allocators. Used for DMA devices that want to
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* share uncached memory with the processor core. The function return
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* is the virtual address and 'dma_handle' is the physical address.
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* Mostly stolen from the ARM port, with some changes for PowerPC.
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* -- Dan
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*
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* Reorganized to get rid of the arch-specific consistent_* functions
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* and provide non-coherent implementations for the DMA API. -Matt
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*
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* Added in_interrupt() safe dma_alloc_coherent()/dma_free_coherent()
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* implementation. This is pulled straight from ARM and barely
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* modified. -Matt
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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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/export.h>
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#include <asm/tlbflush.h>
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#include <asm/dma.h>
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#include "mmu_decl.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 (IOREMAP_TOP)
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#define CONSISTENT_END (CONSISTENT_BASE + 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 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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*/
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void *
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__dma_alloc_coherent(struct device *dev, 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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u64 mask = ISA_DMA_THRESHOLD, limit;
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if (dev) {
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mask = dev->coherent_dma_mask;
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/*
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* Sanity check the DMA mask - it must be non-zero, and
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* must be able to be satisfied by a DMA allocation.
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*/
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if (mask == 0) {
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dev_warn(dev, "coherent DMA mask is unset\n");
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goto no_page;
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}
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if ((~mask) & ISA_DMA_THRESHOLD) {
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dev_warn(dev, "coherent DMA mask %#llx is smaller "
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"than system GFP_DMA mask %#llx\n",
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mask, (unsigned long long)ISA_DMA_THRESHOLD);
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goto no_page;
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}
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}
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size = PAGE_ALIGN(size);
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limit = (mask + 1) & ~mask;
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if ((limit && size >= limit) ||
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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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return NULL;
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}
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order = get_order(size);
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/* Might be useful if we ever have a real legacy DMA zone... */
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if (mask != 0xffffffff)
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gfp |= GFP_DMA;
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page = alloc_pages(gfp, order);
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if (!page)
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goto no_page;
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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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*/
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{
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unsigned long kaddr = (unsigned long)page_address(page);
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memset(page_address(page), 0, size);
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flush_dcache_range(kaddr, kaddr + size);
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}
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/*
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* Allocate a virtual address in the consistent mapping region.
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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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struct page *end = page + (1 << order);
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split_page(page, order);
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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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do {
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SetPageReserved(page);
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map_page(vaddr, page_to_phys(page),
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pgprot_val(pgprot_noncached(PAGE_KERNEL)));
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page++;
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vaddr += PAGE_SIZE;
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} while (size -= PAGE_SIZE);
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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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return (void *)c->vm_start;
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}
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if (page)
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__free_pages(page, order);
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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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/*
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* free a page as defined by the above mapping.
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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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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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addr = c->vm_start;
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do {
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pte_t *ptep;
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unsigned long pfn;
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ptep = pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(addr),
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addr),
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addr),
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addr);
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if (!pte_none(*ptep) && pte_present(*ptep)) {
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pfn = pte_pfn(*ptep);
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pte_clear(&init_mm, addr, ptep);
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if (pfn_valid(pfn)) {
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struct page *page = pfn_to_page(pfn);
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__free_reserved_page(page);
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}
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}
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addr += PAGE_SIZE;
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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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* make an area consistent.
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*/
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void __dma_sync(void *vaddr, size_t size, int direction)
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{
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unsigned long start = (unsigned long)vaddr;
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unsigned long end = start + size;
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switch (direction) {
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case DMA_NONE:
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BUG();
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case DMA_FROM_DEVICE:
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/*
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* invalidate only when cache-line aligned otherwise there is
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* the potential for discarding uncommitted data from the cache
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*/
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if ((start | end) & (L1_CACHE_BYTES - 1))
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flush_dcache_range(start, end);
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else
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invalidate_dcache_range(start, end);
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break;
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case DMA_TO_DEVICE: /* writeback only */
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clean_dcache_range(start, end);
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break;
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case DMA_BIDIRECTIONAL: /* writeback and invalidate */
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flush_dcache_range(start, end);
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break;
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}
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}
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EXPORT_SYMBOL(__dma_sync);
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#ifdef CONFIG_HIGHMEM
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/*
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* __dma_sync_page() implementation for systems using highmem.
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* In this case, each page of a buffer must be kmapped/kunmapped
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* in order to have a virtual address for __dma_sync(). This must
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* not sleep so kmap_atomic()/kunmap_atomic() are used.
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*
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* Note: yes, it is possible and correct to have a buffer extend
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* beyond the first page.
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*/
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static inline void __dma_sync_page_highmem(struct page *page,
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unsigned long offset, size_t size, int direction)
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{
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size_t seg_size = min((size_t)(PAGE_SIZE - offset), size);
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size_t cur_size = seg_size;
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unsigned long flags, start, seg_offset = offset;
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int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE;
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int seg_nr = 0;
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local_irq_save(flags);
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do {
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start = (unsigned long)kmap_atomic(page + seg_nr) + seg_offset;
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/* Sync this buffer segment */
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__dma_sync((void *)start, seg_size, direction);
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kunmap_atomic((void *)start);
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seg_nr++;
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/* Calculate next buffer segment size */
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seg_size = min((size_t)PAGE_SIZE, size - cur_size);
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/* Add the segment size to our running total */
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cur_size += seg_size;
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seg_offset = 0;
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} while (seg_nr < nr_segs);
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local_irq_restore(flags);
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}
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#endif /* CONFIG_HIGHMEM */
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/*
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* __dma_sync_page makes memory consistent. identical to __dma_sync, but
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* takes a struct page instead of a virtual address
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*/
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void __dma_sync_page(struct page *page, unsigned long offset,
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size_t size, int direction)
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{
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#ifdef CONFIG_HIGHMEM
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__dma_sync_page_highmem(page, offset, size, direction);
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#else
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unsigned long start = (unsigned long)page_address(page) + offset;
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__dma_sync((void *)start, size, direction);
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#endif
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}
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EXPORT_SYMBOL(__dma_sync_page);
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/*
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* Return the PFN for a given cpu virtual address returned by
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* __dma_alloc_coherent. This is used by dma_mmap_coherent()
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*/
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unsigned long __dma_get_coherent_pfn(unsigned long cpu_addr)
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{
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/* This should always be populated, so we don't test every
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* level. If that fails, we'll have a nice crash which
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* will be as good as a BUG_ON()
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*/
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pgd_t *pgd = pgd_offset_k(cpu_addr);
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pud_t *pud = pud_offset(pgd, cpu_addr);
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pmd_t *pmd = pmd_offset(pud, cpu_addr);
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pte_t *ptep = pte_offset_kernel(pmd, cpu_addr);
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if (pte_none(*ptep) || !pte_present(*ptep))
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return 0;
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return pte_pfn(*ptep);
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}
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