sh: declared coherent memory support V2 fix

This patch fixes the recently introduced declared coherent memory support.
Without this fix a cached memory area is returned by dma_alloc_coherent() -
unless dma_declare_coherent_memory() has setup a separate area.

This patch makes sure an uncached memory area is returned. With this patch
it is now possible to ping through an rtl8139 interface on r2d-plus.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 20 insertions, 12 deletions

diff --git a/arch/sh/mm/consistent.c b/arch/sh/mm/consistent.c
index 7b2131c9eeda..d3c33fc5b1c2 100644
--- a/arch/sh/mm/consistent.c
+++ b/arch/sh/mm/consistent.c
@@ -26,7 +26,7 @@ struct dma_coherent_mem {
 void *dma_alloc_coherent(struct device *dev, size_t size,
                            dma_addr_t *dma_handle, gfp_t gfp)
 {
-        void *ret;
+        void *ret, *ret_nocache;
         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
         int order = get_order(size);
 
@@ -44,17 +44,24 @@ void *dma_alloc_coherent(struct device *dev, size_t size,
         }
 
         ret = (void *)__get_free_pages(gfp, order);
-
-        if (ret != NULL) {
-                memset(ret, 0, size);
-                /*
-                 * Pages from the page allocator may have data present in
-                 * cache. So flush the cache before using uncached memory.
-                 */
-                dma_cache_sync(NULL, ret, size, DMA_BIDIRECTIONAL);
-                *dma_handle = virt_to_phys(ret);
+        if (!ret)
+                return NULL;
+
+        memset(ret, 0, 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);
+
+        ret_nocache = ioremap_nocache(virt_to_phys(ret), size);
+        if (!ret_nocache) {
+                free_pages((unsigned long)ret, order);
+                return NULL;
         }
-        return ret;
+
+        *dma_handle = virt_to_phys(ret);
+        return ret_nocache;
 }
 EXPORT_SYMBOL(dma_alloc_coherent);
 
@@ -71,7 +78,8 @@ void dma_free_coherent(struct device *dev, size_t size,
         } else {
                 WARN_ON(irqs_disabled());       /* for portability */
                 BUG_ON(mem && mem->flags & DMA_MEMORY_EXCLUSIVE);
-                free_pages((unsigned long)vaddr, order);
+                free_pages((unsigned long)phys_to_virt(dma_handle), order);
+                iounmap(vaddr);
         }
 }
 EXPORT_SYMBOL(dma_free_coherent);