ENGR00217721-4 implement dma_pool_alloc_nonbufferable interface

mm core part

- After USB driver prime a bulk transfer(whatever IN or OUT, take
  OUT for example) on ep1, only one dTD is primed, an USB Interrupt
  (bit 0 of USBSTS) will be issued, and find that endptcomplete
  register is 0x2 which means an OUT transfer on ep1 is completed,
  at this time the ep1 out queue head status is 0x1e18000, and next
  dtd pointer is 0x1 which means transfer is done and everything is
  OK, while the dTD token status is 0x2008080 which means this dTD
  is still active, not completed yet.
- Audio SDMA and Ethernet have the similar issue
- root cause is not found yet
- work around:
  change the non-cacheable bufferable memory to non-cacheable
  non-bufferable memory to make this issue disappear.

Signed-off-by: Tony LIU <junjie.liu@freescale.com>

1 files changed, 88 insertions, 0 deletions

diff --git a/mm/dmapool.c b/mm/dmapool.c
index 03bf3bb4519a..98798f414cb9 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -212,6 +212,32 @@ static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
 	} while (offset < pool->allocation);
 }
 
+#ifdef CONFIG_FSL_UTP
+static struct dma_page *pool_alloc_page_nonbufferable(struct dma_pool *pool, gfp_t mem_flags)
+{
+	struct dma_page *page;
+
+	page = kmalloc(sizeof(*page), mem_flags);
+	if (!page)
+		return NULL;
+	page->vaddr = dma_alloc_noncacheable(pool->dev, pool->allocation,
+					 &page->dma, mem_flags);
+	if (page->vaddr) {
+#ifdef	DMAPOOL_DEBUG
+		memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
+#endif
+		pool_initialise_page(pool, page);
+		list_add(&page->page_list, &pool->page_list);
+		page->in_use = 0;
+		page->offset = 0;
+	} else {
+		kfree(page);
+		page = NULL;
+	}
+	return page;
+}
+#endif
+
 static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
 {
 	struct dma_page *page;
@@ -353,6 +379,68 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
 }
 EXPORT_SYMBOL(dma_pool_alloc);
 
+#ifdef CONFIG_FSL_UTP
+/**
+ * dma_pool_alloc_nonbufferable - get a block of consistent memory
+ * @pool: dma pool that will produce the block
+ * @mem_flags: GFP_* bitmask
+ * @handle: pointer to dma address of block
+ *
+ * This returns the kernel virtual address of a currently unused block,
+ * and reports its dma address through the handle.
+ * If such a memory block can't be allocated, %NULL is returned.
+ */
+void *dma_pool_alloc_nonbufferable(struct dma_pool *pool, gfp_t mem_flags,
+		     dma_addr_t *handle)
+{
+	unsigned long flags;
+	struct dma_page *page;
+	size_t offset;
+	void *retval;
+
+	might_sleep_if(mem_flags & __GFP_WAIT);
+
+	spin_lock_irqsave(&pool->lock, flags);
+ restart:
+	list_for_each_entry(page, &pool->page_list, page_list) {
+		if (page->offset < pool->allocation)
+			goto ready;
+	}
+	page = pool_alloc_page_nonbufferable(pool, GFP_ATOMIC);
+	if (!page) {
+		if (mem_flags & __GFP_WAIT) {
+			DECLARE_WAITQUEUE(wait, current);
+
+			__set_current_state(TASK_UNINTERRUPTIBLE);
+			__add_wait_queue(&pool->waitq, &wait);
+			spin_unlock_irqrestore(&pool->lock, flags);
+
+			schedule_timeout(POOL_TIMEOUT_JIFFIES);
+
+			spin_lock_irqsave(&pool->lock, flags);
+			__remove_wait_queue(&pool->waitq, &wait);
+			goto restart;
+		}
+		retval = NULL;
+		goto done;
+	}
+
+ ready:
+	page->in_use++;
+	offset = page->offset;
+	page->offset = *(int *)(page->vaddr + offset);
+	retval = offset + page->vaddr;
+	*handle = offset + page->dma;
+#ifdef	DMAPOOL_DEBUG
+	memset(retval, POOL_POISON_ALLOCATED, pool->size);
+#endif
+ done:
+	spin_unlock_irqrestore(&pool->lock, flags);
+	return retval;
+}
+EXPORT_SYMBOL(dma_pool_alloc_nonbufferable);
+#endif
+
 static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
 {
 	struct dma_page *page;