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sh: make dma_cache_sync a no-op 

sh does not implement DMA_ATTR_NON_CONSISTENT allocations, so it doesn't
make any sense to do any work in dma_cache_sync given that it
must be a no-op when dma_alloc_attrs returns coherent memory.

On the other hand sh uses dma_cache_sync internally in the dma_ops
implementation and for the maple bus that does not use the DMA API,
so a the old functionality for dma_cache_sync is still provided under
the name sh_sync_dma_for_device, and without the redundant dev
argument.  While at it two of the syncing dma_ops also go the proper
_for_device postfix.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
hifive-unleashed-5.1
Christoph Hellwig 2017-08-27 10:35:40 +02:00
parent d708e71ed7
commit e0c6584df9
4 changed files with 21 additions and 16 deletions
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9
arch/sh/include/asm/dma-mapping.h
View File

@ -9,8 +9,10 @@ static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
return dma_ops;
}
void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
enum dma_data_direction dir);
static inline void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
enum dma_data_direction dir)
{
}
/* arch/sh/mm/consistent.c */
extern void *dma_generic_alloc_coherent(struct device *dev, size_t size,
@ -20,4 +22,7 @@ extern void dma_generic_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle,
unsigned long attrs);
void sh_sync_dma_for_device(void *vaddr, size_t size,
enum dma_data_direction dir);
#endif /* __ASM_SH_DMA_MAPPING_H */

17
arch/sh/kernel/dma-nommu.c
View File

@ -9,6 +9,7 @@
*/
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <asm/cacheflush.h>
static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
@ -20,7 +21,7 @@ static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
WARN_ON(size == 0);
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
dma_cache_sync(dev, page_address(page) + offset, size, dir);
sh_sync_dma_for_device(page_address(page) + offset, size, dir);
return addr;
}
@ -38,7 +39,7 @@ static int nommu_map_sg(struct device *dev, struct scatterlist *sg,
BUG_ON(!sg_page(s));
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
dma_cache_sync(dev, sg_virt(s), s->length, dir);
sh_sync_dma_for_device(sg_virt(s), s->length, dir);
s->dma_address = sg_phys(s);
s->dma_length = s->length;
@ -48,20 +49,20 @@ static int nommu_map_sg(struct device *dev, struct scatterlist *sg,
}
#ifdef CONFIG_DMA_NONCOHERENT
static void nommu_sync_single(struct device *dev, dma_addr_t addr,
static void nommu_sync_single_for_device(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir)
{
dma_cache_sync(dev, phys_to_virt(addr), size, dir);
sh_sync_dma_for_device(phys_to_virt(addr), size, dir);
}
static void nommu_sync_sg(struct device *dev, struct scatterlist *sg,
static void nommu_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir)
{
struct scatterlist *s;
int i;
for_each_sg(sg, s, nelems, i)
dma_cache_sync(dev, sg_virt(s), s->length, dir);
sh_sync_dma_for_device(sg_virt(s), s->length, dir);
}
#endif
@ -71,8 +72,8 @@ const struct dma_map_ops nommu_dma_ops = {
.map_page = nommu_map_page,
.map_sg = nommu_map_sg,
#ifdef CONFIG_DMA_NONCOHERENT
.sync_single_for_device = nommu_sync_single,
.sync_sg_for_device = nommu_sync_sg,
.sync_single_for_device = nommu_sync_single_for_device,
.sync_sg_for_device = nommu_sync_sg_for_device,
#endif
.is_phys = 1,
};

6
arch/sh/mm/consistent.c
View File

@ -49,7 +49,7 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
* Pages from the page allocator may have data present in
* cache. So flush the cache before using uncached memory.
*/
dma_cache_sync(dev, ret, size, DMA_BIDIRECTIONAL);
sh_sync_dma_for_device(ret, size, DMA_BIDIRECTIONAL);
ret_nocache = (void __force *)ioremap_nocache(virt_to_phys(ret), size);
if (!ret_nocache) {
@ -78,7 +78,7 @@ void dma_generic_free_coherent(struct device *dev, size_t size,
iounmap(vaddr);
}
void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
void sh_sync_dma_for_device(void *vaddr, size_t size,
enum dma_data_direction direction)
{
void *addr;
@ -100,7 +100,7 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
BUG();
}
}
EXPORT_SYMBOL(dma_cache_sync);
EXPORT_SYMBOL(sh_sync_dma_for_device);
static int __init memchunk_setup(char *str)
{

5
drivers/sh/maple/maple.c
View File

@ -300,7 +300,7 @@ static void maple_send(void)
mutex_unlock(&maple_wlist_lock);
if (maple_packets > 0) {
for (i = 0; i < (1 << MAPLE_DMA_PAGES); i++)
dma_cache_sync(0, maple_sendbuf + i * PAGE_SIZE,
sh_sync_dma_for_device(maple_sendbuf + i * PAGE_SIZE,
PAGE_SIZE, DMA_BIDIRECTIONAL);
}
@ -642,8 +642,7 @@ static void maple_dma_handler(struct work_struct *work)
list_for_each_entry_safe(mq, nmq, &maple_sentq, list) {
mdev = mq->dev;
recvbuf = mq->recvbuf->buf;
dma_cache_sync(&mdev->dev, recvbuf, 0x400,
DMA_FROM_DEVICE);
sh_sync_dma_for_device(recvbuf, 0x400, DMA_FROM_DEVICE);
code = recvbuf[0];
kfree(mq->sendbuf);
list_del_init(&mq->list);