Remove redundant io_init() function

The intent of io_init() was to allow platform ports to provide
a data object (io_plat_data_t) to the IO storage framework to
allocate into. The abstraction was incomplete because io_plat_data_t
uses a platform defined constant and the IO storage framework
internally allocates other arrays using platform defined constants.

This change simplifies the implementation by instantiating the
supporting objects in the IO storage framework itself. There is now
no need for the platform to call io_init().

The FVP port has been updated accordingly.

THIS CHANGE REQUIRES ALL PLATFORM PORTS THAT USE THE IO STORAGE
FRAMEWORK TO BE UDPATED.

Change-Id: Ib48ac334de9e538064734334c773f8b43df3a7dc

docs/porting-guide.md

@@ -218,6 +218,21 @@ be defined as well:
     the secure memory identified by `TSP_SEC_MEM_BASE` and `TSP_SEC_MEM_SIZE`
     constants.
 
+If the platform port uses the IO storage framework, the following constants
+must also be defined:
+
+*   **#define : MAX_IO_DEVICES**
+
+    Defines the maximum number of registered IO devices. Attempting to register
+    more devices than this value using `io_register_device()` will fail with
+    IO_RESOURCES_EXHAUSTED.
+
+*   **#define : MAX_IO_HANDLES**
+
+    Defines the maximum number of open IO handles. Attempting to open more IO
+    entities than this value using `io_open()` will fail with
+    IO_RESOURCES_EXHAUSTED.
+
 The following constants are optional. They should be defined when the platform
 memory layout implies some image overlaying like on FVP.
 

include/drivers/io_driver.h

@@ -32,7 +32,6 @@
 #define __IO_DRIVER_H__
 
 #include <io_storage.h>
-#include <platform_def.h> /* For MAX_IO_DEVICES */
 #include <stdint.h>
 
 
@@ -76,20 +75,9 @@ typedef struct io_dev_funcs {
 } io_dev_funcs_t;
 
 
-/* IO platform data - used to track devices registered for a specific
- * platform */
-typedef struct io_plat_data {
-	const io_dev_info_t *devices[MAX_IO_DEVICES];
-	unsigned int dev_count;
-} io_plat_data_t;
-
-
 /* Operations intended to be performed during platform initialisation */
 
-/* Initialise the IO layer */
-void io_init(io_plat_data_t *data);
-
-/* Register a device driver */
+/* Register an IO device */
 int io_register_device(const io_dev_info_t *dev_info);
 
 #endif  /* __IO_DRIVER_H__ */

lib/io_storage.c

@@ -31,13 +31,10 @@
 #include <assert.h>
 #include <io_driver.h>
 #include <io_storage.h>
+#include <platform_def.h>
 #include <stddef.h>
 
 
-#define MAX_DEVICES(plat_data)						\
-	(sizeof((plat_data)->devices)/sizeof((plat_data)->devices[0]))
-
-
 /* Storage for a fixed maximum number of IO entities, definable by platform */
 static io_entity_t entity_pool[MAX_IO_HANDLES];
 
@@ -48,9 +45,11 @@ static io_entity_t *entity_map[MAX_IO_HANDLES];
 /* Track number of allocated entities */
 static unsigned int entity_count;
 
+/* Array of fixed maximum of registered devices, definable by platform */
+static const io_dev_info_t *devices[MAX_IO_DEVICES];
 
-/* Used to keep a reference to platform-specific data */
-static io_plat_data_t *platform_data;
+/* Number of currently registered devices */
+static unsigned int dev_count;
 
 
 #if DEBUG	/* Extra validation functions only used in debug builds */
@@ -167,27 +166,15 @@ static int free_entity(const io_entity_t *entity)
 
 /* Exported API */
 
-
-/* Initialise the IO layer */
-void io_init(io_plat_data_t *data)
-{
-	assert(data != NULL);
-	platform_data = data;
-}
-
-
 /* Register a device driver */
 int io_register_device(const io_dev_info_t *dev_info)
 {
 	int result = IO_FAIL;
 	assert(dev_info != NULL);
-	assert(platform_data != NULL);
 
-	unsigned int dev_count = platform_data->dev_count;
-
-	if (dev_count < MAX_DEVICES(platform_data)) {
-		platform_data->devices[dev_count] = dev_info;
-		platform_data->dev_count++;
+	if (dev_count < MAX_IO_DEVICES) {
+		devices[dev_count] = dev_info;
+		dev_count++;
 		result = IO_SUCCESS;
 	} else {
 		result = IO_RESOURCES_EXHAUSTED;

plat/fvp/fvp_io_storage.c

@@ -35,12 +35,11 @@
 #include <io_memmap.h>
 #include <io_storage.h>
 #include <io_semihosting.h>
+#include <platform_def.h>
 #include <semihosting.h>	/* For FOPEN_MODE_... */
 #include <string.h>
-#include "fvp_def.h"
 
 /* IO devices */
-static io_plat_data_t io_data;
 static const io_dev_connector_t *sh_dev_con;
 static uintptr_t sh_dev_spec;
 static uintptr_t sh_init_params;
@@ -172,9 +171,6 @@ void fvp_io_setup (void)
 {
 	int io_result = IO_FAIL;
 
-	/* Initialise the IO layer */
-	io_init(&io_data);
-
 	/* Register the IO devices on this platform */
 	io_result = register_io_dev_sh(&sh_dev_con);
 	assert(io_result == IO_SUCCESS);