Restructure kernel driver source tree

As a first step to have a clearer separation of the different parts of
the kernel driver, the source files have been placed into separate
directories according to their purpose and the different parts are only
allowed to use headers from another part in the include folder.

Files have been renamed accordingly to namespace them by their purpose.

Change-Id: I75e09ebf0002c99a22b6d4b09d34504d186c32b3
Signed-off-by: Mikael Olsson <mikael.olsson@arm.com>
diff --git a/kernel/common/ethosu_dma_mem.c b/kernel/common/ethosu_dma_mem.c
new file mode 100644
index 0000000..0e05978
--- /dev/null
+++ b/kernel/common/ethosu_dma_mem.c
@@ -0,0 +1,77 @@
+/*
+ * SPDX-FileCopyrightText: Copyright 2023-2024 Arm Limited and/or its affiliates <open-source-office@arm.com>
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ * This program is free software and is provided to you under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation, and any use by you of this program is subject to the terms
+ * of such GNU licence.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
+ */
+
+/****************************************************************************
+ * Includes
+ ****************************************************************************/
+
+#include <common/ethosu_dma_mem.h>
+
+#include <linux/err.h>
+#include <linux/dma-mapping.h>
+
+/****************************************************************************
+ * Functions
+ ****************************************************************************/
+
+struct ethosu_dma_mem *ethosu_dma_mem_alloc(struct device *dev,
+					    size_t size)
+{
+	struct ethosu_dma_mem *dma_mem;
+
+	if (!size)
+		return ERR_PTR(-EINVAL);
+
+	dma_mem = devm_kzalloc(dev, sizeof(*dma_mem), GFP_KERNEL);
+	if (!dma_mem)
+		return ERR_PTR(-ENOMEM);
+
+	dma_mem->dev = dev;
+	dma_mem->size = size;
+	dma_mem->cpu_addr = dma_alloc_coherent(dev, size, &dma_mem->dma_addr,
+					       GFP_KERNEL);
+	if (!dma_mem->cpu_addr) {
+		memset(dma_mem, 0, sizeof(*dma_mem));
+		devm_kfree(dev, dma_mem);
+
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return dma_mem;
+}
+
+void ethosu_dma_mem_free(struct ethosu_dma_mem **dma_mem)
+{
+	struct device *dev;
+	struct ethosu_dma_mem *mem;
+
+	if (!dma_mem || !*dma_mem)
+		return;
+
+	mem = *dma_mem;
+	dev = mem->dev;
+
+	memset(mem->cpu_addr, 0, mem->size);
+	dma_free_coherent(dev, mem->size, mem->cpu_addr, mem->dma_addr);
+
+	memset(mem, 0, sizeof(*mem));
+	devm_kfree(dev, mem);
+
+	*dma_mem = NULL;
+}