/* dma-alloc.c: consistent DMA memory allocation
*
* Derived from arch/ppc/mm/cachemap.c
*
* PowerPC version derived from arch/arm/mm/consistent.c
* Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
*
* linux/arch/arm/mm/consistent.c
*
* 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
* Modified for 36-bit support. -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/module.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/stddef.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/hardirq.h>
#include <linux/gfp.h>
#include <asm/pgalloc.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/uaccess.h>
#include <asm/smp.h>
static int map_page(unsigned long va, unsigned long pa, pgprot_t prot)
{
pgd_t *pge;
pud_t *pue;
pmd_t *pme;
pte_t *pte;
int err = -ENOMEM;
/* Use upper 10 bits of VA to index the first level map */
pge = pgd_offset_k(va);
pue = pud_offset(pge, va);
pme = pmd_offset(pue, va);
/* Use middle 10 bits of VA to index the second-level map */
pte = pte_alloc_kernel(pme, va);
if (pte != 0) {
err = 0;
set_pte(pte, mk_pte_phys(pa & PAGE_MASK, prot));
}
return err;
}
/*
* This function will allocate the requested contiguous pages and
* map them into the kernel's vmalloc() space. This is done so we
* get unique mapping for these pages, outside of the kernel's 1:1
* virtual:physical mapping. This is necessary so we can cover large
* portions of the kernel with single large page TLB entries, and
* still get unique uncached pages for consistent DMA.
*/
void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle)
{
struct vm_struct *area;
unsigned long page, va, pa;
void *ret;
int order, err, i;
if (in_interrupt())
BUG();
/* only allocate page size areas */
size = PAGE_ALIGN(size);
order = get_order(size);
page = __get_free_pages(gfp, order);
if (!page) {
BUG();
return NULL;
}
/* allocate some common virtual space to map the new pages */
area = get_vm_area(size, VM_ALLOC);
if (area == 0) {
free_pages(page, order);
return NULL;
}
va = VMALLOC_VMADDR(area->addr);
ret = (void *) va;
/* this gives us the real physical address of the first page */
*dma_handle = pa = virt_to_bus((void *) page);
/* set refcount=1 on all pages in an order>0 allocation so that vfree() will actually free
* all pages that were allocated.
*/
if (order > 0) {
struct page *rpage = virt_to_page(page);
split_page(rpage, order);
}
err = 0;
for (i = 0; i < size && err == 0; i += PAGE_SIZE)
err = map_page(va + i, pa + i, PAGE_KERNEL_NOCACHE);
if (err) {
vfree((void *) va);
return NULL;
}
/* we need to ensure that there are no cachelines in use, or worse dirty in this area
* - can't do until after virtual address mappings are created
*/
frv_cache_invalidate(va, va + size);
return ret;
}
/*
* free page(s) as defined by the above mapping.
*/
void consistent_free(void *vaddr)
{
if (in_interrupt())
BUG();
vfree(vaddr);
}
/*
* make an area consistent.
*/
void consistent_sync(void *vaddr, size_t size, int direction)
{
unsigned long start = (unsigned long) vaddr;
unsigned long end = start + size;
switch (direction) {
case PCI_DMA_NONE:
BUG();
case PCI_DMA_FROMDEVICE: /* invalidate only */
frv_cache_invalidate(start, end);
break;
case PCI_DMA_TODEVICE: /* writeback only */
frv_dcache_writeback(start, end);
break;
case PCI_DMA_BIDIRECTIONAL: /* writeback and invalidate */
frv_dcache_writeback(start, end);
break;
}
}
/*
* consistent_sync_page make a page are consistent. identical
* to consistent_sync, but takes a struct page instead of a virtual address
*/
void consistent_sync_page(struct page *page, unsigned long offset,
size_t size, int direction)
{
void *start;
start = page_address(page) + offset;
consistent_sync(start, size, direction);
}
