Enable per-region CMA DMA-BUF heaps for audio ML offload

arch/arm64/configs/qcom.config

@@ -24,6 +24,7 @@ CONFIG_CPU_IDLE_THERMAL=y
 CONFIG_DEBUG_INFO_BTF=y
 CONFIG_DEBUG_INFO_BTF_MODULES=y
 # CONFIG_MODULE_ALLOW_BTF_MISMATCH is not set
+CONFIG_DMA_CMA=y
 CONFIG_DMABUF_HEAPS=y
 CONFIG_DMABUF_HEAPS_CMA=y
 CONFIG_DMABUF_HEAPS_SYSTEM=y

drivers/dma-buf/heaps/cma_heap.c

@@ -395,33 +395,45 @@ static int __init __add_cma_heap(struct cma *cma, const char *name)
 	return 0;
 }
 
-static int __init add_default_cma_heap(void)
+static int __init add_cma_heaps(void)
 {
 	struct cma *default_cma = dev_get_cma_area(NULL);
 	const char *legacy_cma_name;
+	struct cma *cma;
+	unsigned int i;
 	int ret;
 
-	if (!default_cma)
-		return 0;
-
-	ret = __add_cma_heap(default_cma, DEFAULT_CMA_NAME);
-	if (ret)
-		return ret;
-
-	if (IS_ENABLED(CONFIG_DMABUF_HEAPS_CMA_LEGACY)) {
-		legacy_cma_name = cma_get_name(default_cma);
-		if (!strcmp(legacy_cma_name, DEFAULT_CMA_NAME)) {
-			pr_warn("legacy name and default name are the same, skipping legacy heap\n");
-			return 0;
+	if (default_cma) {
+		ret = __add_cma_heap(default_cma, DEFAULT_CMA_NAME);
+		if (ret)
+			return ret;
+
+		if (IS_ENABLED(CONFIG_DMABUF_HEAPS_CMA_LEGACY)) {
+			legacy_cma_name = cma_get_name(default_cma);
+			if (!strcmp(legacy_cma_name, DEFAULT_CMA_NAME)) {
+				pr_warn("legacy name and default name are the same, skipping legacy heap\n");
+				goto add_additional_heaps;
+			}
+
+			ret = __add_cma_heap(default_cma, legacy_cma_name);
+			if (ret)
+				pr_warn("failed to add legacy heap: %pe\n",
+					ERR_PTR(ret));
 		}
+	}
+
+add_additional_heaps:
+	for (i = 0; (cma = dma_contiguous_get_area_by_idx(i)) != NULL; i++) {
+		if (cma == default_cma)
+			continue;
 
-		ret = __add_cma_heap(default_cma, legacy_cma_name);
+		ret = __add_cma_heap(cma, cma_get_name(cma));
 		if (ret)
-			pr_warn("failed to add legacy heap: %pe\n",
-				ERR_PTR(ret));
+			pr_warn("failed to add CMA heap %s: %pe\n",
+				cma_get_name(cma), ERR_PTR(ret));
 	}
 
 	return 0;
 }
-module_init(add_default_cma_heap);
+module_init(add_cma_heaps);
 MODULE_DESCRIPTION("DMA-BUF CMA Heap");

include/linux/dma-map-ops.h

@@ -98,6 +98,7 @@ static inline void set_dma_ops(struct device *dev,
 
 #ifdef CONFIG_DMA_CMA
 extern struct cma *dma_contiguous_default_area;
+struct cma *dma_contiguous_get_area_by_idx(unsigned int idx);
 
 static inline struct cma *dev_get_cma_area(struct device *dev)
 {
@@ -156,6 +157,11 @@ static inline void dma_free_contiguous(struct device *dev, struct page *page,
 static inline void dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
 {
 }
+
+static inline struct cma *dma_contiguous_get_area_by_idx(unsigned int idx)
+{
+	return NULL;
+}
 #endif /* CONFIG_DMA_CMA*/
 
 #ifdef CONFIG_DMA_DECLARE_COHERENT

kernel/dma/contiguous.c

@@ -53,6 +53,27 @@
 #endif
 
 struct cma *dma_contiguous_default_area;
+static struct cma *dma_contiguous_areas[MAX_CMA_AREAS];
+static unsigned int dma_contiguous_areas_num;
+
+static int dma_contiguous_insert_area(struct cma *cma)
+{
+	if (dma_contiguous_areas_num >= ARRAY_SIZE(dma_contiguous_areas))
+		return -EINVAL;
+
+	dma_contiguous_areas[dma_contiguous_areas_num++] = cma;
+
+	return 0;
+}
+
+struct cma *dma_contiguous_get_area_by_idx(unsigned int idx)
+{
+	if (idx >= dma_contiguous_areas_num)
+		return NULL;
+
+	return dma_contiguous_areas[idx];
+}
+EXPORT_SYMBOL_GPL(dma_contiguous_get_area_by_idx);
 
 /*
  * Default global CMA area size can be defined in kernel's .config.
@@ -251,13 +272,21 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
 	}
 
 	if (selected_size && !dma_contiguous_default_area) {
+		int ret;
+
 		pr_debug("%s: reserving %ld MiB for global area\n", __func__,
 			 (unsigned long)selected_size / SZ_1M);
 
-		dma_contiguous_reserve_area(selected_size, selected_base,
-					    selected_limit,
-					    &dma_contiguous_default_area,
-					    fixed);
+		ret = dma_contiguous_reserve_area(selected_size, selected_base,
+						  selected_limit,
+						  &dma_contiguous_default_area,
+						  fixed);
+		if (ret)
+			return;
+
+		ret = dma_contiguous_insert_area(dma_contiguous_default_area);
+		if (ret)
+			pr_warn("Couldn't queue default CMA region for heap creation.\n");
 	}
 }
 
@@ -497,6 +526,10 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
 	pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
 		&rmem->base, (unsigned long)rmem->size / SZ_1M);
 
+	err = dma_contiguous_insert_area(cma);
+	if (err)
+		pr_warn("Couldn't store CMA reserved area.\n");
+
 	return 0;
 }
 RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);