arm:no longer rely on a 1:1 phys mapping for device memory.

Change-Id: Ie3f61069f882c37dbb81dee813fdfd883e7468cf

kernel/arch/earm/include/arch_proto.h

@@ -53,6 +53,67 @@ extern void * k_stacks;
 					+ 2 * ((cpu) + 1) * K_STACK_SIZE))
 
 
+/*
+ * Definition of a callback used when a memory map changes it's base address
+ */
+typedef int (*kern_phys_map_mapped)(vir_bytes id, vir_bytes new_addr );
+
+/*
+ * struct used internally by memory.c to keep a list of
+ * items to map. These should be staticaly allocated 
+ * in the individual files and passed as argument. 
+ * The data doesn't need to be initialized. See omap_serial for
+ * and example usage.
+ */
+typedef struct kern_phys_map{
+	phys_bytes addr; /* The physical address to map */
+	vir_bytes size;  /* The size of the mapping */
+	vir_bytes id;	 /* an id passed to the callback */
+	kern_phys_map_mapped cb; /* the callback itself */
+	phys_bytes vir; /* The virtual address once remapped */
+	int index; 	/* index */
+	struct kern_phys_map *next; /* pointer to the next */
+} kern_phys_map ; 
+
+
+/*
+ * Request an in kernel physical mapping.
+ * 
+ * On ARM many devices are memory mapped and some of these devices
+ * are used in the kernel. These device can be things like serial 
+ * lines, interrupt controller and clocks. The kernel needs to be 
+ * able to access these devices at the various stages of booting. 
+ * During startup, until arch_enable_paging is called, it is the 
+ * kernel whom is controlling the mappings and it often needs to 
+ * access the memory using a 1:1 mapping between virtual and 
+ * physical memory.
+ * 
+ * Once processes start to run it is no longer desirable for the 
+ * kernel to have devices mapped in the middle of the process
+ * address space. 
+ *
+ * This method requests the memory manager to map base_address/size 
+ * in the kernel address space and call back the kernel when this 
+ * mapping takes effect (after enable_paging).
+ *
+ * Before the callback is called it is up to the kernel to use it's
+ * own addressing. The callback will happen *after* the kernel lost
+ * it's initial mapping. It it therefore not safe to use the initial
+ * mapping in the callback. It also is not possible to use printf for
+ * the same reason.
+ */
+int kern_req_phys_map( phys_bytes base_address, vir_bytes io_size,
+		   kern_phys_map * priv, kern_phys_map_mapped cb, 
+		   vir_bytes id);
+
+/*
+ * Request a physical mapping and put the result in the given prt
+ * Note that ptr will only be valid once the callback happend.
+ */
+int kern_phys_map_ptr( phys_bytes base_address, vir_bytes io_size, 
+	kern_phys_map * priv, vir_bytes ptr);
+
+
 /* functions defined in architecture-independent kernel source. */
 #include "kernel/proto.h"