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linux-next/arch/powerpc/lib/dma-noncoherent.c
David Howells 8168b5400b powerpc: Rename struct vm_region to avoid conflict with NOMMU
Rename PowerPC's struct vm_region so that I can introduce my own
global version for NOMMU.  It's feasible that the PowerPC version may
wish to use my global one instead.

The NOMMU vm_region struct defines areas of the physical memory map
that are under mmap.  This may include chunks of RAM or regions of
memory mapped devices, such as flash.  It is also used to retain
copies of file content so that shareable private memory mappings of
files can be made.  As such, it may be compatible with what is
described in the banner comment for PowerPC's vm_region struct.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-12-21 14:21:14 +11:00

427 lines
10 KiB
C

/*
* PowerPC version derived from arch/arm/mm/consistent.c
* Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
*
* Copyright (C) 2000 Russell King
*
* Consistent memory allocators. Used for DMA devices that want to
* share uncached memory with the processor core. The function return
* is the virtual address and 'dma_handle' is the physical address.
* Mostly stolen from the ARM port, with some changes for PowerPC.
* -- Dan
*
* Reorganized to get rid of the arch-specific consistent_* functions
* and provide non-coherent implementations for the DMA API. -Matt
*
* Added in_interrupt() safe dma_alloc_coherent()/dma_free_coherent()
* implementation. This is pulled straight from ARM and barely
* modified. -Matt
*
* 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.
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/highmem.h>
#include <linux/dma-mapping.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.
*/
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;
u64 mask = 0x00ffffff, limit; /* ISA default */
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) || size >= (CONSISTENT_END - CONSISTENT_BASE)) {
printk(KERN_WARNING "coherent allocation too big (requested %#x mask %#Lx)\n",
size, mask);
return NULL;
}
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);
flush_dcache_range(kaddr, kaddr + size);
}
/*
* Allocate a virtual address in the consistent mapping region.
*/
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);
do {
BUG_ON(!pte_none(*pte));
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;
}
if (page)
__free_pages(page, order);
no_page:
return NULL;
}
EXPORT_SYMBOL(__dma_alloc_coherent);
/*
* free a page as defined by the above mapping.
*/
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;
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.
*/
void __dma_sync(void *vaddr, size_t size, int direction)
{
unsigned long start = (unsigned long)vaddr;
unsigned long end = start + size;
switch (direction) {
case DMA_NONE:
BUG();
case DMA_FROM_DEVICE:
/*
* invalidate only when cache-line aligned otherwise there is
* the potential for discarding uncommitted data from the cache
*/
if ((start & (L1_CACHE_BYTES - 1)) || (size & (L1_CACHE_BYTES - 1)))
flush_dcache_range(start, end);
else
invalidate_dcache_range(start, end);
break;
case DMA_TO_DEVICE: /* writeback only */
clean_dcache_range(start, end);
break;
case DMA_BIDIRECTIONAL: /* writeback and invalidate */
flush_dcache_range(start, end);
break;
}
}
EXPORT_SYMBOL(__dma_sync);
#ifdef CONFIG_HIGHMEM
/*
* __dma_sync_page() implementation for systems using highmem.
* In this case, each page of a buffer must be kmapped/kunmapped
* in order to have a virtual address for __dma_sync(). This must
* not sleep so kmap_atomic()/kunmap_atomic() are used.
*
* Note: yes, it is possible and correct to have a buffer extend
* beyond the first page.
*/
static inline void __dma_sync_page_highmem(struct page *page,
unsigned long offset, size_t size, int direction)
{
size_t seg_size = min((size_t)(PAGE_SIZE - offset), size);
size_t cur_size = seg_size;
unsigned long flags, start, seg_offset = offset;
int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE;
int seg_nr = 0;
local_irq_save(flags);
do {
start = (unsigned long)kmap_atomic(page + seg_nr,
KM_PPC_SYNC_PAGE) + seg_offset;
/* Sync this buffer segment */
__dma_sync((void *)start, seg_size, direction);
kunmap_atomic((void *)start, KM_PPC_SYNC_PAGE);
seg_nr++;
/* Calculate next buffer segment size */
seg_size = min((size_t)PAGE_SIZE, size - cur_size);
/* Add the segment size to our running total */
cur_size += seg_size;
seg_offset = 0;
} while (seg_nr < nr_segs);
local_irq_restore(flags);
}
#endif /* CONFIG_HIGHMEM */
/*
* __dma_sync_page makes memory consistent. identical to __dma_sync, but
* takes a struct page instead of a virtual address
*/
void __dma_sync_page(struct page *page, unsigned long offset,
size_t size, int direction)
{
#ifdef CONFIG_HIGHMEM
__dma_sync_page_highmem(page, offset, size, direction);
#else
unsigned long start = (unsigned long)page_address(page) + offset;
__dma_sync((void *)start, size, direction);
#endif
}
EXPORT_SYMBOL(__dma_sync_page);