/*
* Meta version derived from arch/powerpc/lib/dma-noncoherent.c
* Copyright (C) 2008 Imagination Technologies Ltd.
*
* 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/export.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/highmem.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <asm/tlbflush.h>
#include <asm/mmu.h>
#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_START) \
>> PAGE_SHIFT)
static u64 get_coherent_dma_mask(struct device *dev)
{
u64 mask = ~0ULL;
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");
return 0;
}
}
return mask;
}
/*
* 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 metag_vm_region region;
* unsigned long flags;
* struct page **pages;
* unsigned int nr_pages;
* unsigned long phys_addr;
* };
*
* get_vm_area() would then call metag_vm_region_alloc with an appropriate
* struct metag_vm_region head (eg):
*
* struct metag_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
* metag_vm_region_alloc().
*/
struct metag_vm_region {
struct list_head vm_list;
unsigned long vm_start;
unsigned long vm_end;
struct page *vm_pages;
int vm_active;
};
static struct metag_vm_region consistent_head = {
.vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
.vm_start = CONSISTENT_START,
.vm_end = CONSISTENT_END,
};
static struct metag_vm_region *metag_vm_region_alloc(struct metag_vm_region
*head, size_t size,
gfp_t gfp)
{
unsigned long addr = head->vm_start, end = head->vm_end - size;
unsigned long flags;
struct metag_vm_region *c, *new;
new = kmalloc(sizeof(struct metag_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;
new->vm_active = 1;
spin_unlock_irqrestore(&consistent_lock, flags);
return new;
nospc:
spin_unlock_irqrestore(&consistent_lock, flags);
kfree(new);
out:
return NULL;
}
static struct metag_vm_region *metag_vm_region_find(struct metag_vm_region
*head, unsigned long addr)
{
struct metag_vm_region *c;
list_for_each_entry(c, &head->vm_list, vm_list) {
if (c->vm_active && 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(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp)
{
struct page *page;
struct metag_vm_region *c;
unsigned long order;
u64 mask = get_coherent_dma_mask(dev);
u64 limit;
if (!consistent_pte) {
pr_err("%s: not initialised\n", __func__);
dump_stack();
return NULL;
}
if (!mask)
goto no_page;
size = PAGE_ALIGN(size);
limit = (mask + 1) & ~mask;
if ((limit && size >= limit)
|| size >= (CONSISTENT_END - CONSISTENT_START)) {
pr_warn("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.
*/
{
void *kaddr = page_address(page);
memset(kaddr, 0, size);
flush_dcache_region(kaddr, size);
}
/*
* Allocate a virtual address in the consistent mapping region.
*/
c = metag_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);
c->vm_pages = page;
split_page(page, order);
/*
* Set the "dma handle"
*/
*handle = page_to_bus(page);
do {
BUG_ON(!pte_none(*pte));
SetPageReserved(page);
set_pte_at(&init_mm, vaddr,
pte, mk_pte(page,
pgprot_writecombine
(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(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle)
{
struct metag_vm_region *c;
unsigned long flags, addr;
pte_t *ptep;
size = PAGE_ALIGN(size);
spin_lock_irqsave(&consistent_lock, flags);
c = metag_vm_region_find(&consistent_head, (unsigned long)vaddr);
if (!c)
goto no_area;
c->vm_active = 0;
if ((c->vm_end - c->vm_start) != size) {
pr_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;
}
}
pr_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);
pr_err("%s: trying to free invalid coherent area: %p\n",
__func__, vaddr);
dump_stack();
}
EXPORT_SYMBOL(dma_free_coherent);
static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size)
{
int ret = -ENXIO;
unsigned long flags, user_size, kern_size;
struct metag_vm_region *c;
user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
spin_lock_irqsave(&consistent_lock, flags);
c = metag_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)) {
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);
/*
* Initialise the consistent memory allocation.
*/
static int __init dma_alloc_init(void)
{
pgd_t *pgd, *pgd_k;
pud_t *pud, *pud_k;
pmd_t *pmd, *pmd_k;
pte_t *pte;
int ret = 0;
do {
int offset = pgd_index(CONSISTENT_START);
pgd = pgd_offset(&init_mm, CONSISTENT_START);
pud = pud_alloc(&init_mm, pgd, CONSISTENT_START);
pmd = pmd_alloc(&init_mm, pud, CONSISTENT_START);
if (!pmd) {
pr_err("%s: no pmd tables\n", __func__);
ret = -ENOMEM;
break;
}
WARN_ON(!pmd_none(*pmd));
pte = pte_alloc_kernel(pmd, CONSISTENT_START);
if (!pte) {
pr_err("%s: no pte tables\n", __func__);
ret = -ENOMEM;
break;
}
pgd_k = ((pgd_t *) mmu_get_base()) + offset;
pud_k = pud_offset(pgd_k, CONSISTENT_START);
pmd_k = pmd_offset(pud_k, CONSISTENT_START);
set_pmd(pmd_k, *pmd);
consistent_pte = pte;
} while (0);
return ret;
}
early_initcall(dma_alloc_init);
/*
* make an area consistent to devices.
*/
void dma_sync_for_device(void *vaddr, size_t size, int dma_direction)
{
/*
* Ensure any writes get through the write combiner. This is necessary
* even with DMA_FROM_DEVICE, or the write may dirty the cache after
* we've invalidated it and get written back during the DMA.
*/
barrier();
switch (dma_direction) {
case DMA_BIDIRECTIONAL:
/*
* Writeback to ensure the device can see our latest changes and
* so that we have no dirty lines, and invalidate the cache
* lines too in preparation for receiving the buffer back
* (dma_sync_for_cpu) later.
*/
flush_dcache_region(vaddr, size);
break;
case DMA_TO_DEVICE:
/*
* Writeback to ensure the device can see our latest changes.
* There's no need to invalidate as the device shouldn't write
* to the buffer.
*/
writeback_dcache_region(vaddr, size);
break;
case DMA_FROM_DEVICE:
/*
* Invalidate to ensure we have no dirty lines that could get
* written back during the DMA. It's also safe to flush
* (writeback) here if necessary.
*/
invalidate_dcache_region(vaddr, size);
break;
case DMA_NONE:
BUG();
}
wmb();
}
EXPORT_SYMBOL(dma_sync_for_device);
/*
* make an area consistent to the core.
*/
void dma_sync_for_cpu(void *vaddr, size_t size, int dma_direction)
{
/*
* Hardware L2 cache prefetch doesn't occur across 4K physical
* boundaries, however according to Documentation/DMA-API-HOWTO.txt
* kmalloc'd memory is DMA'able, so accesses in nearby memory could
* trigger a cache fill in the DMA buffer.
*
* This should never cause dirty lines, so a flush or invalidate should
* be safe to allow us to see data from the device.
*/
if (_meta_l2c_pf_is_enabled()) {
switch (dma_direction) {
case DMA_BIDIRECTIONAL:
case DMA_FROM_DEVICE:
invalidate_dcache_region(vaddr, size);
break;
case DMA_TO_DEVICE:
/* The device shouldn't have written to the buffer */
break;
case DMA_NONE:
BUG();
}
}
rmb();
}
EXPORT_SYMBOL(dma_sync_for_cpu);