ion: "unmapped" heap for secure data path

OP-TEE/SDP (Secure Data Path) memory pools are created through ION
secure type heap" from Allwinner. This change renames "secure" into
"unmapped" as, from Linux point of view, the heap constraint is
manipulating unampped memory pools/buffers.

"Unmapped" heap support is integrated in ION UAPI (actually this was
the Allwinner initial proposal) and ION DT parsing support.

Based in work from Sunny <sunny@allwinnertech.com> for Allwinner.

Changes:
- rename "secure_heap" into "unmapped_heap"
- define ION_HEAP_TYPE_UNMAPPED in ION UAPI (sic!)
- add structure "struct unmapped_buffer_priv" to hold allocated buffer
  private data (currently only the buffer physical address.
- adapt to recent ION (i.e ion_phys_addr_t => phys_addr_t)
- Support dummy heap configuration: one can hard code into the Linux
  kernel configuration the location of a "unmapped heap". It will be
  created during ION device inits: see CONFIG_ION_DUMMY_UNMAPPED_HEAP.

Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>

drivers/staging/android/ion/Kconfig

@@ -42,3 +42,35 @@ config ION_CMA_HEAP
 	  Choose this option to enable CMA heaps with Ion. This heap is backed
 	  by the Contiguous Memory Allocator (CMA). If your system has these
 	  regions, you should say Y here.
+
+config ION_UNMAPPED_HEAP
+	bool "ION unmapped heap support"
+	depends on ION
+	help
+	  Choose this option to enable UNMAPPED heaps with Ion. This heap is
+	  backed in specific memory pools, carveout from the Linux memory.
+	  Unless you know your system has these regions, you should say N here.
+
+config ION_DUMMY_UNMAPPED_HEAP
+	bool "ION dummy driver define an ION unmapped heap"
+	depends on ION_UNMAPPED_HEAP
+	help
+	  Dummy ION driver will create a unmapped heap from physical
+	  location provided through CONFIG_ION_DUMMY_UNMAPPED_BASE and
+	  CONFIG_ION_DUMMY_UNMAPPED_SIZE.
+
+config ION_DUMMY_UNMAPPED_BASE
+	hex "Physical base address of the ION unmapped heap"
+	depends on ION_DUMMY_UNMAPPED_HEAP
+	default 0
+	help
+	  Allows one the statically define an unmapped heap from the
+	  ION dummy driver to exercice unamped heaps buffer managment.
+
+config ION_DUMMY_UNMAPPED_SIZE
+	hex "Physical byte size of the ION unmapped heap"
+	depends on ION_DUMMY_UNMAPPED_HEAP
+	default 0
+	help
+	  Allows one the statically define an unmapped heap from the
+	  ION dummy driver to exercice unamped heaps buffer managment.

drivers/staging/android/ion/Makefile

@@ -3,3 +3,4 @@ obj-$(CONFIG_ION_SYSTEM_HEAP) += ion_system_heap.o ion_page_pool.o
 obj-$(CONFIG_ION_CARVEOUT_HEAP) += ion_carveout_heap.o
 obj-$(CONFIG_ION_CHUNK_HEAP) += ion_chunk_heap.o
 obj-$(CONFIG_ION_CMA_HEAP) += ion_cma_heap.o
+obj-$(CONFIG_ION_UNMAPPED_HEAP) += ion_unmapped_heap.o