dmaengine, async_tx: add a "no channel switch" allocator

[safe/jmp/linux-2.6] / drivers / dma / dmaengine.c

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 9659847..d5bc628 100644 (file)
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -608,6 +608,40 @@ void dmaengine_put(void)
 }
 EXPORT_SYMBOL(dmaengine_put);
 
+static bool device_has_all_tx_types(struct dma_device *device)
+{
+       /* A device that satisfies this test has channels that will never cause
+        * an async_tx channel switch event as all possible operation types can
+        * be handled.
+        */
+       #ifdef CONFIG_ASYNC_TX_DMA
+       if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
+               return false;
+       #endif
+
+       #if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
+       if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
+               return false;
+       #endif
+
+       #if defined(CONFIG_ASYNC_MEMSET) || defined(CONFIG_ASYNC_MEMSET_MODULE)
+       if (!dma_has_cap(DMA_MEMSET, device->cap_mask))
+               return false;
+       #endif
+
+       #if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
+       if (!dma_has_cap(DMA_XOR, device->cap_mask))
+               return false;
+       #endif
+
+       #if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
+       if (!dma_has_cap(DMA_PQ, device->cap_mask))
+               return false;
+       #endif
+
+       return true;
+}
+
 static int get_dma_id(struct dma_device *device)
 {
        int rc;
@@ -665,6 +699,12 @@ int dma_async_device_register(struct dma_device *device)
        BUG_ON(!device->device_issue_pending);
        BUG_ON(!device->dev);
 
+       /* note: this only matters in the
+        * CONFIG_ASYNC_TX_DISABLE_CHANNEL_SWITCH=y case
+        */
+       if (device_has_all_tx_types(device))
+               dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
+
        idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
        if (!idr_ref)
                return -ENOMEM;