[media] st-delta: add memory allocator helper functions

Helper functions used by decoder back-ends to allocate
physically contiguous memory required by hardware video
decoder.
Acked-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Hugues Fruchet <hugues.fruchet@st.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/sti/delta/Makefile

 obj-$(CONFIG_VIDEO_STI_DELTA_DRIVER) := st-delta.o
-st-delta-y := delta-v4l2.o
+st-delta-y := delta-v4l2.o delta-mem.o

drivers/media/platform/sti/delta/delta-mem.c

+/*
+ * Copyright (C) STMicroelectronics SA 2015
+ * Author: Hugues Fruchet <hugues.fruchet@st.com> for STMicroelectronics.
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#include "delta.h"
+#include "delta-mem.h"
+
+int hw_alloc(struct delta_ctx *ctx, u32 size, const char *name,
+	     struct delta_buf *buf)
+{
+	struct delta_dev *delta = ctx->dev;
+	dma_addr_t dma_addr;
+	void *addr;
+	unsigned long attrs = DMA_ATTR_WRITE_COMBINE;
+
+	addr = dma_alloc_attrs(delta->dev, size, &dma_addr,
+			       GFP_KERNEL | __GFP_NOWARN, attrs);
+	if (!addr) {
+		dev_err(delta->dev,
+			"%s hw_alloc:dma_alloc_coherent failed for %s (size=%d)\n",
+			ctx->name, name, size);
+		ctx->sys_errors++;
+		return -ENOMEM;
+	}
+
+	buf->size = size;
+	buf->paddr = dma_addr;
+	buf->vaddr = addr;
+	buf->name = name;
+	buf->attrs = attrs;
+
+	dev_dbg(delta->dev,
+		"%s allocate %d bytes of HW memory @(virt=0x%p, phy=0x%pad): %s\n",
+		ctx->name, size, buf->vaddr, &buf->paddr, buf->name);
+
+	return 0;
+}
+
+void hw_free(struct delta_ctx *ctx, struct delta_buf *buf)
+{
+	struct delta_dev *delta = ctx->dev;
+
+	dev_dbg(delta->dev,
+		"%s     free %d bytes of HW memory @(virt=0x%p, phy=0x%pad): %s\n",
+		ctx->name, buf->size, buf->vaddr, &buf->paddr, buf->name);
+
+	dma_free_attrs(delta->dev, buf->size,
+		       buf->vaddr, buf->paddr, buf->attrs);
+}

drivers/media/platform/sti/delta/delta-mem.h

+/*
+ * Copyright (C) STMicroelectronics SA 2015
+ * Author: Hugues Fruchet <hugues.fruchet@st.com> for STMicroelectronics.
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#ifndef DELTA_MEM_H
+#define DELTA_MEM_H
+
+int hw_alloc(struct delta_ctx *ctx, u32 size, const char *name,
+	     struct delta_buf *buf);
+void hw_free(struct delta_ctx *ctx, struct delta_buf *buf);
+
+#endif /* DELTA_MEM_H */

drivers/media/platform/sti/delta/delta.h

@@ -191,6 +191,14 @@ struct delta_dts {
 	u64 val;
 };
 
+struct delta_buf {
+	u32 size;
+	void *vaddr;
+	dma_addr_t paddr;
+	const char *name;
+	unsigned long attrs;
+};
+
 struct delta_ctx;
 
 /*