xtensa: support DMA to high memory
- don't bugcheck if high memory page is passed to xtensa_map_page;
- turn empty dcache flush macros into functions so that they could be
passed as function parameters;
- use kmap_atomic to map high memory pages for cache invalidation/
flushing performed by xtensa_sync_single_for_{cpu,device}.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
diff --git a/arch/xtensa/include/asm/cacheflush.h b/arch/xtensa/include/asm/cacheflush.h
index 7158881..397d6a1 100644
--- a/arch/xtensa/include/asm/cacheflush.h
+++ b/arch/xtensa/include/asm/cacheflush.h
@@ -55,9 +55,14 @@
extern void __flush_invalidate_dcache_page(unsigned long);
extern void __flush_invalidate_dcache_range(unsigned long, unsigned long);
#else
-# define __flush_dcache_range(p,s) do { } while(0)
-# define __flush_dcache_page(p) do { } while(0)
-# define __flush_invalidate_dcache_page(p) __invalidate_dcache_page(p)
+static inline void __flush_dcache_page(unsigned long va)
+{
+}
+static inline void __flush_dcache_range(unsigned long va, unsigned long sz)
+{
+}
+# define __flush_invalidate_dcache_all() __invalidate_dcache_all()
+# define __flush_invalidate_dcache_page(p) __invalidate_dcache_page(p)
# define __flush_invalidate_dcache_range(p,s) __invalidate_dcache_range(p,s)
#endif
diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
index fb75ebf..cd66698 100644
--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -15,14 +15,15 @@
* Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
*/
-#include <linux/types.h>
-#include <linux/mm.h>
-#include <linux/string.h>
-#include <linux/pci.h>
#include <linux/gfp.h>
+#include <linux/highmem.h>
+#include <linux/mm.h>
#include <linux/module.h>
-#include <asm/io.h>
+#include <linux/pci.h>
+#include <linux/string.h>
+#include <linux/types.h>
#include <asm/cacheflush.h>
+#include <asm/io.h>
void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
enum dma_data_direction dir)
@@ -47,17 +48,36 @@
}
EXPORT_SYMBOL(dma_cache_sync);
+static void do_cache_op(dma_addr_t dma_handle, size_t size,
+ void (*fn)(unsigned long, unsigned long))
+{
+ unsigned long off = dma_handle & (PAGE_SIZE - 1);
+ unsigned long pfn = PFN_DOWN(dma_handle);
+ struct page *page = pfn_to_page(pfn);
+
+ if (!PageHighMem(page))
+ fn((unsigned long)bus_to_virt(dma_handle), size);
+ else
+ while (size > 0) {
+ size_t sz = min_t(size_t, size, PAGE_SIZE - off);
+ void *vaddr = kmap_atomic(page);
+
+ fn((unsigned long)vaddr + off, sz);
+ kunmap_atomic(vaddr);
+ off = 0;
+ ++page;
+ size -= sz;
+ }
+}
+
static void xtensa_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size,
enum dma_data_direction dir)
{
- void *vaddr;
-
switch (dir) {
case DMA_BIDIRECTIONAL:
case DMA_FROM_DEVICE:
- vaddr = bus_to_virt(dma_handle);
- __invalidate_dcache_range((unsigned long)vaddr, size);
+ do_cache_op(dma_handle, size, __invalidate_dcache_range);
break;
case DMA_NONE:
@@ -73,13 +93,11 @@
dma_addr_t dma_handle, size_t size,
enum dma_data_direction dir)
{
- void *vaddr;
-
switch (dir) {
case DMA_BIDIRECTIONAL:
case DMA_TO_DEVICE:
- vaddr = bus_to_virt(dma_handle);
- __flush_dcache_range((unsigned long)vaddr, size);
+ if (XCHAL_DCACHE_IS_WRITEBACK)
+ do_cache_op(dma_handle, size, __flush_dcache_range);
break;
case DMA_NONE:
@@ -171,7 +189,6 @@
{
dma_addr_t dma_handle = page_to_phys(page) + offset;
- BUG_ON(PageHighMem(page));
xtensa_sync_single_for_device(dev, dma_handle, size, dir);
return dma_handle;
}