gpu: ion: Add support for specifying a default prefetch size

Some heaps now support prefetching memory before allocation occurs.
This currently requires a size to be given to prefetch a given size.
Clients may not know what size they need to prefetch for a given
heap. Since the optimal size may change with the target, add an option
into devicetree to specify what size should be prefetched by default.
Clients may specify a size of 0 to prefetch a the default size.

Change-Id: If15e4051d53fe284129c309101c41ee423f890f9
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>

Documentation/devicetree/bindings/arm/msm/msm_ion.txt

@@ -37,6 +37,8 @@ Optional properties for Ion heaps
 - qcom,memory-reservation-size: size of reserved memory for the ION heap.
 - qcom,memory-reservation-type: type of memory to be reserved
 (see memory-reserve.txt for information about memory reservations)
+- qcom,default-prefetch-size: Based value to be used for prefetching
+  optimizations. Ignored if the heap does not support prefetching.
 
 Example:
 	qcom,ion {

drivers/gpu/ion/ion_cma_secure_heap.c

@@ -92,6 +92,7 @@ struct ion_cma_secure_heap {
 	atomic_t total_allocated;
 	atomic_t total_pool_size;
 	unsigned long heap_size;
+	unsigned long default_prefetch_size;
 };
 
 static void ion_secure_pool_pages(struct work_struct *work);
@@ -224,6 +225,9 @@ int ion_secure_cma_prefetch(struct ion_heap *heap, void *data)
 	if ((int) heap->type != ION_HEAP_TYPE_SECURE_DMA)
 		return -EINVAL;
 
+	if (len == 0)
+		len = sheap->default_prefetch_size;
+
 	/*
 	 * Only prefetch as much space as there is left in the pool so
 	 * check against the current free size of the heap.
@@ -667,14 +671,19 @@ struct ion_heap *ion_secure_cma_heap_create(struct ion_platform_heap *data)
 	sheap->shrinker.seeks = DEFAULT_SEEKS;
 	sheap->shrinker.batch = 0;
 	sheap->shrinker.shrink = ion_secure_cma_shrinker;
+	sheap->default_prefetch_size = sheap->heap_size;
 	register_shrinker(&sheap->shrinker);
 
-
 	if (!sheap->bitmap) {
 		kfree(sheap);
 		return ERR_PTR(-ENOMEM);
 	}
 
+	if (data->extra_data) {
+		struct ion_cma_pdata *extra = data->extra_data;
+		sheap->default_prefetch_size = extra->default_prefetch_size;
+	}
+
 	/*
 	 * we initially mark everything in the allocator as being free so that
 	 * allocations can come in later

drivers/gpu/ion/msm/msm_ion.c

@@ -554,7 +554,8 @@ static void check_for_heap_overlap(const struct ion_platform_heap heap_list[],
 }
 
 #ifdef CONFIG_OF
-static int msm_init_extra_data(struct ion_platform_heap *heap,
+static int msm_init_extra_data(struct device_node *node,
+			       struct ion_platform_heap *heap,
 			       const struct ion_heap_desc *heap_desc)
 {
 	int ret = 0;
@@ -580,6 +581,28 @@ static int msm_init_extra_data(struct ion_platform_heap *heap,
 			ret = -ENOMEM;
 		break;
 	}
+	case ION_HEAP_TYPE_SECURE_DMA:
+	{
+		unsigned int val;
+
+		ret = of_property_read_u32(node,
+					"qcom,default-prefetch-size", &val);
+
+		if (!ret) {
+			heap->extra_data = kzalloc(sizeof(struct ion_cma_pdata),
+					   GFP_KERNEL);
+
+			if (!heap->extra_data) {
+				ret = -ENOMEM;
+			} else {
+				struct ion_cma_pdata *extra = heap->extra_data;
+				extra->default_prefetch_size = val;
+			}
+		} else {
+			ret = 0;
+		}
+		break;
+	}
 	default:
 		heap->extra_data = 0;
 		break;
@@ -639,7 +662,8 @@ static int msm_ion_populate_heap(struct device_node *node,
 			if (ret)
 				break;
 			heap->type = heap_type;
-			ret = msm_init_extra_data(heap, &ion_heap_meta[i]);
+			ret = msm_init_extra_data(node, heap,
+						&ion_heap_meta[i]);
 			break;
 		}
 	}

include/linux/msm_ion.h

@@ -197,6 +197,14 @@ struct ion_co_heap_pdata {
 	enum ion_memory_types memory_type;
 };
 
+/*
+ * struct ion_cma_pdata - extra data for CMA regions
+ * @default_prefetch_size - default size to use for prefetching
+ */
+struct ion_cma_pdata {
+	unsigned long default_prefetch_size;
+};
+
 #ifdef CONFIG_ION
 /**
  *  msm_ion_client_create - allocate a client using the ion_device specified in