1 files changed, 270 insertions, 101 deletions

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
index cd7feb1b25f6..fc419bb8eab7 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
@@ -23,35 +23,42 @@
 /*
  * GK20A does not have dedicated video memory, and to accurately represent this
  * fact Nouveau will not create a RAM device for it. Therefore its instmem
- * implementation must be done directly on top of system memory, while providing
- * coherent read and write operations.
+ * implementation must be done directly on top of system memory, while
+ * preserving coherency for read and write operations.
  *
  * Instmem can be allocated through two means:
- * 1) If an IOMMU mapping has been probed, the IOMMU API is used to make memory
+ * 1) If an IOMMU unit has been probed, the IOMMU API is used to make memory
  *    pages contiguous to the GPU. This is the preferred way.
- * 2) If no IOMMU mapping is probed, the DMA API is used to allocate physically
+ * 2) If no IOMMU unit is probed, the DMA API is used to allocate physically
  *    contiguous memory.
  *
- * In both cases CPU read and writes are performed using PRAMIN (i.e. using the
- * GPU path) to ensure these operations are coherent for the GPU. This allows us
- * to use more "relaxed" allocation parameters when using the DMA API, since we
- * never need a kernel mapping.
+ * In both cases CPU read and writes are performed by creating a write-combined
+ * mapping. The GPU L2 cache must thus be flushed/invalidated when required. To
+ * be conservative we do this every time we acquire or release an instobj, but
+ * ideally L2 management should be handled at a higher level.
+ *
+ * To improve performance, CPU mappings are not removed upon instobj release.
+ * Instead they are placed into a LRU list to be recycled when the mapped space
+ * goes beyond a certain threshold. At the moment this limit is 1MB.
  */
-#define gk20a_instmem(p) container_of((p), struct gk20a_instmem, base)
 #include "priv.h"
 
 #include <core/memory.h>
 #include <core/mm.h>
 #include <core/tegra.h>
 #include <subdev/fb.h>
-
-#define gk20a_instobj(p) container_of((p), struct gk20a_instobj, memory)
+#include <subdev/ltc.h>
 
 struct gk20a_instobj {
 	struct nvkm_memory memory;
-	struct gk20a_instmem *imem;
 	struct nvkm_mem mem;
+	struct gk20a_instmem *imem;
+
+	/* CPU mapping */
+	u32 *vaddr;
+	struct list_head vaddr_node;
 };
+#define gk20a_instobj(p) container_of((p), struct gk20a_instobj, memory)
 
 /*
  * Used for objects allocated using the DMA API
@@ -59,10 +66,12 @@ struct gk20a_instobj {
 struct gk20a_instobj_dma {
 	struct gk20a_instobj base;
 
-	void *cpuaddr;
+	u32 *cpuaddr;
 	dma_addr_t handle;
 	struct nvkm_mm_node r;
 };
+#define gk20a_instobj_dma(p) \
+	container_of(gk20a_instobj(p), struct gk20a_instobj_dma, base)
 
 /*
  * Used for objects flattened using the IOMMU API
@@ -70,25 +79,38 @@ struct gk20a_instobj_dma {
 struct gk20a_instobj_iommu {
 	struct gk20a_instobj base;
 
-	/* array of base.mem->size pages */
+	/* will point to the higher half of pages */
+	dma_addr_t *dma_addrs;
+	/* array of base.mem->size pages (+ dma_addr_ts) */
 	struct page *pages[];
 };
+#define gk20a_instobj_iommu(p) \
+	container_of(gk20a_instobj(p), struct gk20a_instobj_iommu, base)
 
 struct gk20a_instmem {
 	struct nvkm_instmem base;
-	unsigned long lock_flags;
+
+	/* protects vaddr_* and gk20a_instobj::vaddr* */
 	spinlock_t lock;
-	u64 addr;
+
+	/* CPU mappings LRU */
+	unsigned int vaddr_use;
+	unsigned int vaddr_max;
+	struct list_head vaddr_lru;
 
 	/* Only used if IOMMU if present */
 	struct mutex *mm_mutex;
 	struct nvkm_mm *mm;
 	struct iommu_domain *domain;
 	unsigned long iommu_pgshift;
+	u16 iommu_bit;
 
 	/* Only used by DMA API */
 	struct dma_attrs attrs;
+
+	void __iomem * (*cpu_map)(struct nvkm_memory *);
 };
+#define gk20a_instmem(p) container_of((p), struct gk20a_instmem, base)
 
 static enum nvkm_memory_target
 gk20a_instobj_target(struct nvkm_memory *memory)
@@ -100,7 +122,6 @@ static u64
 gk20a_instobj_addr(struct nvkm_memory *memory)
 {
 	return gk20a_instobj(memory)->mem.offset;
-
 }
 
 static u64
@@ -110,107 +131,217 @@ gk20a_instobj_size(struct nvkm_memory *memory)
 }
 
 static void __iomem *
+gk20a_instobj_cpu_map_dma(struct nvkm_memory *memory)
+{
+	struct gk20a_instobj_dma *node = gk20a_instobj_dma(memory);
+	struct device *dev = node->base.imem->base.subdev.device->dev;
+	int npages = nvkm_memory_size(memory) >> 12;
+	struct page *pages[npages];
+	int i;
+
+	/* phys_to_page does not exist on all platforms... */
+	pages[0] = pfn_to_page(dma_to_phys(dev, node->handle) >> PAGE_SHIFT);
+	for (i = 1; i < npages; i++)
+		pages[i] = pages[0] + i;
+
+	return vmap(pages, npages, VM_MAP, pgprot_writecombine(PAGE_KERNEL));
+}
+
+static void __iomem *
+gk20a_instobj_cpu_map_iommu(struct nvkm_memory *memory)
+{
+	struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
+	int npages = nvkm_memory_size(memory) >> 12;
+
+	return vmap(node->pages, npages, VM_MAP,
+		    pgprot_writecombine(PAGE_KERNEL));
+}
+
+/*
+ * Must be called while holding gk20a_instmem_lock
+ */
+static void
+gk20a_instmem_vaddr_gc(struct gk20a_instmem *imem, const u64 size)
+{
+	while (imem->vaddr_use + size > imem->vaddr_max) {
+		struct gk20a_instobj *obj;
+
+		/* no candidate that can be unmapped, abort... */
+		if (list_empty(&imem->vaddr_lru))
+			break;
+
+		obj = list_first_entry(&imem->vaddr_lru, struct gk20a_instobj,
+				       vaddr_node);
+		list_del(&obj->vaddr_node);
+		vunmap(obj->vaddr);
+		obj->vaddr = NULL;
+		imem->vaddr_use -= nvkm_memory_size(&obj->memory);
+		nvkm_debug(&imem->base.subdev, "(GC) vaddr used: %x/%x\n",
+			   imem->vaddr_use, imem->vaddr_max);
+
+	}
+}
+
+static void __iomem *
 gk20a_instobj_acquire(struct nvkm_memory *memory)
 {
-	struct gk20a_instmem *imem = gk20a_instobj(memory)->imem;
+	struct gk20a_instobj *node = gk20a_instobj(memory);
+	struct gk20a_instmem *imem = node->imem;
+	struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
+	const u64 size = nvkm_memory_size(memory);
 	unsigned long flags;
+
+	nvkm_ltc_flush(ltc);
+
 	spin_lock_irqsave(&imem->lock, flags);
-	imem->lock_flags = flags;
-	return NULL;
+
+	if (node->vaddr) {
+		/* remove us from the LRU list since we cannot be unmapped */
+		list_del(&node->vaddr_node);
+
+		goto out;
+	}
+
+	/* try to free some address space if we reached the limit */
+	gk20a_instmem_vaddr_gc(imem, size);
+
+	node->vaddr = imem->cpu_map(memory);
+
+	if (!node->vaddr) {
+		nvkm_error(&imem->base.subdev, "cannot map instobj - "
+			   "this is not going to end well...\n");
+		goto out;
+	}
+
+	imem->vaddr_use += size;
+	nvkm_debug(&imem->base.subdev, "vaddr used: %x/%x\n",
+		   imem->vaddr_use, imem->vaddr_max);
+
+out:
+	spin_unlock_irqrestore(&imem->lock, flags);
+
+	return node->vaddr;
 }
 
 static void
 gk20a_instobj_release(struct nvkm_memory *memory)
 {
-	struct gk20a_instmem *imem = gk20a_instobj(memory)->imem;
-	spin_unlock_irqrestore(&imem->lock, imem->lock_flags);
-}
+	struct gk20a_instobj *node = gk20a_instobj(memory);
+	struct gk20a_instmem *imem = node->imem;
+	struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
+	unsigned long flags;
 
-/*
- * Use PRAMIN to read/write data and avoid coherency issues.
- * PRAMIN uses the GPU path and ensures data will always be coherent.
- *
- * A dynamic mapping based solution would be desirable in the future, but
- * the issue remains of how to maintain coherency efficiently. On ARM it is
- * not easy (if possible at all?) to create uncached temporary mappings.
- */
+	spin_lock_irqsave(&imem->lock, flags);
+
+	/* add ourselves to the LRU list so our CPU mapping can be freed */
+	list_add_tail(&node->vaddr_node, &imem->vaddr_lru);
+
+	spin_unlock_irqrestore(&imem->lock, flags);
+
+	wmb();
+	nvkm_ltc_invalidate(ltc);
+}
 
 static u32
 gk20a_instobj_rd32(struct nvkm_memory *memory, u64 offset)
 {
 	struct gk20a_instobj *node = gk20a_instobj(memory);
-	struct gk20a_instmem *imem = node->imem;
-	struct nvkm_device *device = imem->base.subdev.device;
-	u64 base = (node->mem.offset + offset) & 0xffffff00000ULL;
-	u64 addr = (node->mem.offset + offset) & 0x000000fffffULL;
-	u32 data;
-
-	if (unlikely(imem->addr != base)) {
-		nvkm_wr32(device, 0x001700, base >> 16);
-		imem->addr = base;
-	}
-	data = nvkm_rd32(device, 0x700000 + addr);
-	return data;
+
+	return node->vaddr[offset / 4];
 }
 
 static void
 gk20a_instobj_wr32(struct nvkm_memory *memory, u64 offset, u32 data)
 {
 	struct gk20a_instobj *node = gk20a_instobj(memory);
-	struct gk20a_instmem *imem = node->imem;
-	struct nvkm_device *device = imem->base.subdev.device;
-	u64 base = (node->mem.offset + offset) & 0xffffff00000ULL;
-	u64 addr = (node->mem.offset + offset) & 0x000000fffffULL;
 
-	if (unlikely(imem->addr != base)) {
-		nvkm_wr32(device, 0x001700, base >> 16);
-		imem->addr = base;
-	}
-	nvkm_wr32(device, 0x700000 + addr, data);
+	node->vaddr[offset / 4] = data;
 }
 
 static void
 gk20a_instobj_map(struct nvkm_memory *memory, struct nvkm_vma *vma, u64 offset)
 {
 	struct gk20a_instobj *node = gk20a_instobj(memory);
+
 	nvkm_vm_map_at(vma, offset, &node->mem);
 }
 
+/*
+ * Clear the CPU mapping of an instobj if it exists
+ */
 static void
-gk20a_instobj_dtor_dma(struct gk20a_instobj *_node)
+gk20a_instobj_dtor(struct gk20a_instobj *node)
+{
+	struct gk20a_instmem *imem = node->imem;
+	struct gk20a_instobj *obj;
+	unsigned long flags;
+
+	spin_lock_irqsave(&imem->lock, flags);
+
+	if (!node->vaddr)
+		goto out;
+
+	list_for_each_entry(obj, &imem->vaddr_lru, vaddr_node) {
+		if (obj == node) {
+			list_del(&obj->vaddr_node);
+			break;
+		}
+	}
+	vunmap(node->vaddr);
+	node->vaddr = NULL;
+	imem->vaddr_use -= nvkm_memory_size(&node->memory);
+	nvkm_debug(&imem->base.subdev, "vaddr used: %x/%x\n",
+		   imem->vaddr_use, imem->vaddr_max);
+
+out:
+	spin_unlock_irqrestore(&imem->lock, flags);
+}
+
+static void *
+gk20a_instobj_dtor_dma(struct nvkm_memory *memory)
 {
-	struct gk20a_instobj_dma *node = (void *)_node;
-	struct gk20a_instmem *imem = _node->imem;
+	struct gk20a_instobj_dma *node = gk20a_instobj_dma(memory);
+	struct gk20a_instmem *imem = node->base.imem;
 	struct device *dev = imem->base.subdev.device->dev;
 
+	gk20a_instobj_dtor(&node->base);
+
 	if (unlikely(!node->cpuaddr))
-		return;
+		goto out;
 
-	dma_free_attrs(dev, _node->mem.size << PAGE_SHIFT, node->cpuaddr,
+	dma_free_attrs(dev, node->base.mem.size << PAGE_SHIFT, node->cpuaddr,
 		       node->handle, &imem->attrs);
+
+out:
+	return node;
 }
 
-static void
-gk20a_instobj_dtor_iommu(struct gk20a_instobj *_node)
+static void *
+gk20a_instobj_dtor_iommu(struct nvkm_memory *memory)
 {
-	struct gk20a_instobj_iommu *node = (void *)_node;
-	struct gk20a_instmem *imem = _node->imem;
+	struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
+	struct gk20a_instmem *imem = node->base.imem;
+	struct device *dev = imem->base.subdev.device->dev;
 	struct nvkm_mm_node *r;
 	int i;
 
-	if (unlikely(list_empty(&_node->mem.regions)))
-		return;
+	gk20a_instobj_dtor(&node->base);
 
-	r = list_first_entry(&_node->mem.regions, struct nvkm_mm_node,
+	if (unlikely(list_empty(&node->base.mem.regions)))
+		goto out;
+
+	r = list_first_entry(&node->base.mem.regions, struct nvkm_mm_node,
 			     rl_entry);
 
-	/* clear bit 34 to unmap pages */
-	r->offset &= ~BIT(34 - imem->iommu_pgshift);
+	/* clear IOMMU bit to unmap pages */
+	r->offset &= ~BIT(imem->iommu_bit - imem->iommu_pgshift);
 
 	/* Unmap pages from GPU address space and free them */
-	for (i = 0; i < _node->mem.size; i++) {
+	for (i = 0; i < node->base.mem.size; i++) {
 		iommu_unmap(imem->domain,
 			    (r->offset + i) << imem->iommu_pgshift, PAGE_SIZE);
+		dma_unmap_page(dev, node->dma_addrs[i], PAGE_SIZE,
+			       DMA_BIDIRECTIONAL);
 		__free_page(node->pages[i]);
 	}
 
@@ -218,25 +349,27 @@ gk20a_instobj_dtor_iommu(struct gk20a_instobj *_node)
 	mutex_lock(imem->mm_mutex);
 	nvkm_mm_free(imem->mm, &r);
 	mutex_unlock(imem->mm_mutex);
-}
-
-static void *
-gk20a_instobj_dtor(struct nvkm_memory *memory)
-{
-	struct gk20a_instobj *node = gk20a_instobj(memory);
-	struct gk20a_instmem *imem = node->imem;
-
-	if (imem->domain)
-		gk20a_instobj_dtor_iommu(node);
-	else
-		gk20a_instobj_dtor_dma(node);
 
+out:
 	return node;
 }
 
 static const struct nvkm_memory_func
-gk20a_instobj_func = {
-	.dtor = gk20a_instobj_dtor,
+gk20a_instobj_func_dma = {
+	.dtor = gk20a_instobj_dtor_dma,
+	.target = gk20a_instobj_target,
+	.addr = gk20a_instobj_addr,
+	.size = gk20a_instobj_size,
+	.acquire = gk20a_instobj_acquire,
+	.release = gk20a_instobj_release,
+	.rd32 = gk20a_instobj_rd32,
+	.wr32 = gk20a_instobj_wr32,
+	.map = gk20a_instobj_map,
+};
+
+static const struct nvkm_memory_func
+gk20a_instobj_func_iommu = {
+	.dtor = gk20a_instobj_dtor_iommu,
 	.target = gk20a_instobj_target,
 	.addr = gk20a_instobj_addr,
 	.size = gk20a_instobj_size,
@@ -259,6 +392,8 @@ gk20a_instobj_ctor_dma(struct gk20a_instmem *imem, u32 npages, u32 align,
 		return -ENOMEM;
 	*_node = &node->base;
 
+	nvkm_memory_ctor(&gk20a_instobj_func_dma, &node->base.memory);
+
 	node->cpuaddr = dma_alloc_attrs(dev, npages << PAGE_SHIFT,
 					&node->handle, GFP_KERNEL,
 					&imem->attrs);
@@ -292,24 +427,40 @@ gk20a_instobj_ctor_iommu(struct gk20a_instmem *imem, u32 npages, u32 align,
 {
 	struct gk20a_instobj_iommu *node;
 	struct nvkm_subdev *subdev = &imem->base.subdev;
+	struct device *dev = subdev->device->dev;
 	struct nvkm_mm_node *r;
 	int ret;
 	int i;
 
-	if (!(node = kzalloc(sizeof(*node) +
-			     sizeof( node->pages[0]) * npages, GFP_KERNEL)))
+	/*
+	 * despite their variable size, instmem allocations are small enough
+	 * (< 1 page) to be handled by kzalloc
+	 */
+	if (!(node = kzalloc(sizeof(*node) + ((sizeof(node->pages[0]) +
+			     sizeof(*node->dma_addrs)) * npages), GFP_KERNEL)))
 		return -ENOMEM;
 	*_node = &node->base;
+	node->dma_addrs = (void *)(node->pages + npages);
+
+	nvkm_memory_ctor(&gk20a_instobj_func_iommu, &node->base.memory);
 
 	/* Allocate backing memory */
 	for (i = 0; i < npages; i++) {
 		struct page *p = alloc_page(GFP_KERNEL);
+		dma_addr_t dma_adr;
 
 		if (p == NULL) {
 			ret = -ENOMEM;
 			goto free_pages;
 		}
 		node->pages[i] = p;
+		dma_adr = dma_map_page(dev, p, 0, PAGE_SIZE, DMA_BIDIRECTIONAL);
+		if (dma_mapping_error(dev, dma_adr)) {
+			nvkm_error(subdev, "DMA mapping error!\n");
+			ret = -ENOMEM;
+			goto free_pages;
+		}
+		node->dma_addrs[i] = dma_adr;
 	}
 
 	mutex_lock(imem->mm_mutex);
@@ -318,16 +469,15 @@ gk20a_instobj_ctor_iommu(struct gk20a_instmem *imem, u32 npages, u32 align,
 			   align >> imem->iommu_pgshift, &r);
 	mutex_unlock(imem->mm_mutex);
 	if (ret) {
-		nvkm_error(subdev, "virtual space is full!\n");
+		nvkm_error(subdev, "IOMMU space is full!\n");
 		goto free_pages;
 	}
 
 	/* Map into GPU address space */
 	for (i = 0; i < npages; i++) {
-		struct page *p = node->pages[i];
 		u32 offset = (r->offset + i) << imem->iommu_pgshift;
 
-		ret = iommu_map(imem->domain, offset, page_to_phys(p),
+		ret = iommu_map(imem->domain, offset, node->dma_addrs[i],
 				PAGE_SIZE, IOMMU_READ | IOMMU_WRITE);
 		if (ret < 0) {
 			nvkm_error(subdev, "IOMMU mapping failure: %d\n", ret);
@@ -340,8 +490,8 @@ gk20a_instobj_ctor_iommu(struct gk20a_instmem *imem, u32 npages, u32 align,
 		}
 	}
 
-	/* Bit 34 tells that an address is to be resolved through the IOMMU */
-	r->offset |= BIT(34 - imem->iommu_pgshift);
+	/* IOMMU bit tells that an address is to be resolved through the IOMMU */
+	r->offset |= BIT(imem->iommu_bit - imem->iommu_pgshift);
 
 	node->base.mem.offset = ((u64)r->offset) << imem->iommu_pgshift;
 
@@ -356,8 +506,13 @@ release_area:
 	mutex_unlock(imem->mm_mutex);
 
 free_pages:
-	for (i = 0; i < npages && node->pages[i] != NULL; i++)
+	for (i = 0; i < npages && node->pages[i] != NULL; i++) {
+		dma_addr_t dma_addr = node->dma_addrs[i];
+		if (dma_addr)
+			dma_unmap_page(dev, dma_addr, PAGE_SIZE,
+				       DMA_BIDIRECTIONAL);
 		__free_page(node->pages[i]);
+	}
 
 	return ret;
 }
@@ -367,8 +522,8 @@ gk20a_instobj_new(struct nvkm_instmem *base, u32 size, u32 align, bool zero,
 		  struct nvkm_memory **pmemory)
 {
 	struct gk20a_instmem *imem = gk20a_instmem(base);
-	struct gk20a_instobj *node = NULL;
 	struct nvkm_subdev *subdev = &imem->base.subdev;
+	struct gk20a_instobj *node = NULL;
 	int ret;
 
 	nvkm_debug(subdev, "%s (%s): size: %x align: %x\n", __func__,
@@ -388,7 +543,6 @@ gk20a_instobj_new(struct nvkm_instmem *base, u32 size, u32 align, bool zero,
 	if (ret)
 		return ret;
 
-	nvkm_memory_ctor(&gk20a_instobj_func, &node->memory);
 	node->imem = imem;
 
 	/* present memory for being mapped using small pages */
@@ -402,15 +556,25 @@ gk20a_instobj_new(struct nvkm_instmem *base, u32 size, u32 align, bool zero,
 	return 0;
 }
 
-static void
-gk20a_instmem_fini(struct nvkm_instmem *base)
+static void *
+gk20a_instmem_dtor(struct nvkm_instmem *base)
 {
-	gk20a_instmem(base)->addr = ~0ULL;
+	struct gk20a_instmem *imem = gk20a_instmem(base);
+
+	/* perform some sanity checks... */
+	if (!list_empty(&imem->vaddr_lru))
+		nvkm_warn(&base->subdev, "instobj LRU not empty!\n");
+
+	if (imem->vaddr_use != 0)
+		nvkm_warn(&base->subdev, "instobj vmap area not empty! "
+			  "0x%x bytes still mapped\n", imem->vaddr_use);
+
+	return imem;
 }
 
 static const struct nvkm_instmem_func
 gk20a_instmem = {
-	.fini = gk20a_instmem_fini,
+	.dtor = gk20a_instmem_dtor,
 	.memory_new = gk20a_instobj_new,
 	.persistent = true,
 	.zero = false,
@@ -429,23 +593,28 @@ gk20a_instmem_new(struct nvkm_device *device, int index,
 	spin_lock_init(&imem->lock);
 	*pimem = &imem->base;
 
+	/* do not allow more than 1MB of CPU-mapped instmem */
+	imem->vaddr_use = 0;
+	imem->vaddr_max = 0x100000;
+	INIT_LIST_HEAD(&imem->vaddr_lru);
+
 	if (tdev->iommu.domain) {
-		imem->domain = tdev->iommu.domain;
+		imem->mm_mutex = &tdev->iommu.mutex;
 		imem->mm = &tdev->iommu.mm;
+		imem->domain = tdev->iommu.domain;
 		imem->iommu_pgshift = tdev->iommu.pgshift;
-		imem->mm_mutex = &tdev->iommu.mutex;
+		imem->cpu_map = gk20a_instobj_cpu_map_iommu;
+		imem->iommu_bit = tdev->func->iommu_bit;
 
 		nvkm_info(&imem->base.subdev, "using IOMMU\n");
 	} else {
 		init_dma_attrs(&imem->attrs);
-		/*
-		 * We will access instmem through PRAMIN and thus do not need a
-		 * consistent CPU pointer or kernel mapping
-		 */
+		/* We will access the memory through our own mapping */
 		dma_set_attr(DMA_ATTR_NON_CONSISTENT, &imem->attrs);
 		dma_set_attr(DMA_ATTR_WEAK_ORDERING, &imem->attrs);
 		dma_set_attr(DMA_ATTR_WRITE_COMBINE, &imem->attrs);
 		dma_set_attr(DMA_ATTR_NO_KERNEL_MAPPING, &imem->attrs);
+		imem->cpu_map = gk20a_instobj_cpu_map_dma;
 
 		nvkm_info(&imem->base.subdev, "using DMA API\n");
 	}