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ARM: 8547/1: dma-mapping: store buffer information 

Keep a list of allocated DMA buffers so that we can store metadata in
alloc() which we later need in free().

Signed-off-by: Rabin Vincent <rabin.vincent@axis.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Rabin Vincent 2016-03-03 15:58:00 +01:00 committed by Russell King
parent f57deb0be5
commit 19e6e5e539
1 changed files with 48 additions and 1 deletions
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49
arch/arm/mm/dma-mapping.c
View File

@ -42,6 +42,31 @@
#include "dma.h"
#include "mm.h"
struct arm_dma_buffer {
struct list_head list;
void *virt;
};
static LIST_HEAD(arm_dma_bufs);
static DEFINE_SPINLOCK(arm_dma_bufs_lock);
static struct arm_dma_buffer *arm_dma_buffer_find(void *virt)
{
struct arm_dma_buffer *buf, *found = NULL;
unsigned long flags;
spin_lock_irqsave(&arm_dma_bufs_lock, flags);
list_for_each_entry(buf, &arm_dma_bufs, list) {
if (buf->virt == virt) {
list_del(&buf->list);
found = buf;
break;
}
}
spin_unlock_irqrestore(&arm_dma_bufs_lock, flags);
return found;
}
/*
* The DMA API is built upon the notion of "buffer ownership". A buffer
* is either exclusively owned by the CPU (and therefore may be accessed
@ -620,6 +645,7 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
struct page *page = NULL;
void *addr;
bool want_vaddr;
struct arm_dma_buffer *buf;
#ifdef CONFIG_DMA_API_DEBUG
u64 limit = (mask + 1) & ~mask;
@ -633,6 +659,10 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
if (!mask)
return NULL;
buf = kzalloc(sizeof(*buf), gfp);
if (!buf)
return NULL;
if (mask < 0xffffffffULL)
gfp |= GFP_DMA;
@ -662,8 +692,18 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
addr = __alloc_remap_buffer(dev, size, gfp, prot, &page,
caller, want_vaddr);
if (page)
if (page) {
unsigned long flags;
*handle = pfn_to_dma(dev, page_to_pfn(page));
buf->virt = want_vaddr ? addr : page;
spin_lock_irqsave(&arm_dma_bufs_lock, flags);
list_add(&buf->list, &arm_dma_bufs);
spin_unlock_irqrestore(&arm_dma_bufs_lock, flags);
} else {
kfree(buf);
}
return want_vaddr ? addr : page;
}
@ -742,6 +782,11 @@ static void __arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
{
struct page *page = pfn_to_page(dma_to_pfn(dev, handle));
bool want_vaddr = !dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs);
struct arm_dma_buffer *buf;
buf = arm_dma_buffer_find(cpu_addr);
if (WARN(!buf, "Freeing invalid buffer %p\n", cpu_addr))
return;
size = PAGE_ALIGN(size);
@ -760,6 +805,8 @@ static void __arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
WARN_ON(irqs_disabled());
__free_from_contiguous(dev, page, cpu_addr, size, want_vaddr);
}
kfree(buf);
}
void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,