Remove variables from .data section

Update code base to remove variables from the .data section,
mainly by using const static data where possible and adding
the const specifier as required. Most changes are to the IO
subsystem, including the framework APIs. The FVP power
management code is also affected.

Delay initialization of the global static variable,
next_image_type in bl31_main.c, until it is realy needed.
Doing this moves the variable from the .data to the .bss
section.

Also review the IO interface for inconsistencies, using
uintptr_t where possible instead of void *. Remove the
io_handle and io_dev_handle typedefs, which were
unnecessary, replacing instances with uintptr_t.

Fixes ARM-software/tf-issues#107.

Change-Id: I085a62197c82410b566e4698e5590063563ed304

2 files changed, 51 insertions, 45 deletions

diff --git a/lib/io_storage.c b/lib/io_storage.c
index 01ca1c68..204310a4 100644
--- a/lib/io_storage.c
+++ b/lib/io_storage.c
@@ -64,9 +64,9 @@ static int is_valid_dev_connector(const io_dev_connector_t *dev_con)
 
 
 /* Return a boolean value indicating whether a device handle is valid */
-static int is_valid_dev(io_dev_handle handle)
+static int is_valid_dev(const uintptr_t dev_handle)
 {
-	const io_dev_info_t *dev = handle;
+	const io_dev_info_t *dev = (io_dev_info_t *)dev_handle;
 	int result = (dev != NULL) && (dev->funcs != NULL) &&
 			(dev->funcs->type != NULL) &&
 			(dev->funcs->type() < IO_TYPE_MAX);
@@ -75,10 +75,11 @@ static int is_valid_dev(io_dev_handle handle)
 
 
 /* Return a boolean value indicating whether an IO entity is valid */
-static int is_valid_entity(io_handle handle)
+static int is_valid_entity(const uintptr_t handle)
 {
-	const io_entity_t *entity = handle;
-	int result = (entity != NULL) && (is_valid_dev(entity->dev_handle));
+	const io_entity_t *entity = (io_entity_t *)handle;
+	int result = (entity != NULL) &&
+			(is_valid_dev((uintptr_t)entity->dev_handle));
 	return result;
 }
 
@@ -93,7 +94,7 @@ static int is_valid_seek_mode(io_seek_mode_t mode)
 
 
 /* Open a connection to a specific device */
-static int dev_open(const io_dev_connector_t *dev_con, void *dev_spec,
+static int dev_open(const io_dev_connector_t *dev_con, const uintptr_t dev_spec,
 		io_dev_info_t **dev_info)
 {
 	int result = IO_FAIL;
@@ -106,15 +107,15 @@ static int dev_open(const io_dev_connector_t *dev_con, void *dev_spec,
 
 
 /* Set a handle to track an entity */
-static void set_handle(io_handle *handle, io_entity_t *entity)
+static void set_handle(uintptr_t *handle, io_entity_t *entity)
 {
 	assert(handle != NULL);
-	*handle = entity;
+	*handle = (uintptr_t)entity;
 }
 
 
 /* Locate an entity in the pool, specified by address */
-static int find_first_entity(struct io_entity *entity, unsigned int *index_out)
+static int find_first_entity(const io_entity_t *entity, unsigned int *index_out)
 {
 	int result = IO_FAIL;
 	for (int index = 0; index < MAX_IO_HANDLES; ++index) {
@@ -129,7 +130,7 @@ static int find_first_entity(struct io_entity *entity, unsigned int *index_out)
 
 
 /* Allocate an entity from the pool and return a pointer to it */
-static int allocate_entity(struct io_entity **entity)
+static int allocate_entity(io_entity_t **entity)
 {
 	int result = IO_FAIL;
 	assert(entity != NULL);
@@ -148,7 +149,7 @@ static int allocate_entity(struct io_entity **entity)
 
 
 /* Release an entity back to the pool */
-static int free_entity(struct io_entity *entity)
+static int free_entity(const io_entity_t *entity)
 {
 	int result = IO_FAIL;
 	unsigned int index = 0;
@@ -168,7 +169,7 @@ static int free_entity(struct io_entity *entity)
 
 
 /* Initialise the IO layer */
-void io_init(struct io_plat_data *data)
+void io_init(io_plat_data_t *data)
 {
 	assert(data != NULL);
 	platform_data = data;
@@ -176,7 +177,7 @@ void io_init(struct io_plat_data *data)
 
 
 /* Register a device driver */
-int io_register_device(struct io_dev_info *dev_info)
+int io_register_device(const io_dev_info_t *dev_info)
 {
 	int result = IO_FAIL;
 	assert(dev_info != NULL);
@@ -197,26 +198,26 @@ int io_register_device(struct io_dev_info *dev_info)
 
 
 /* Open a connection to an IO device */
-int io_dev_open(struct io_dev_connector *dev_con, void *dev_spec,
-		io_dev_handle *handle)
+int io_dev_open(const io_dev_connector_t *dev_con, const uintptr_t dev_spec,
+		uintptr_t *handle)
 {
 	int result = IO_FAIL;
 	assert(handle != NULL);
 
-	result = dev_open(dev_con, dev_spec, handle);
+	result = dev_open(dev_con, dev_spec, (io_dev_info_t **)handle);
 	return result;
 }
 
 
 /* Initialise an IO device explicitly - to permit lazy initialisation or
  * re-initialisation */
-int io_dev_init(struct io_dev_info *dev_handle, const void *init_params)
+int io_dev_init(uintptr_t dev_handle, const uintptr_t init_params)
 {
 	int result = IO_FAIL;
-	assert(dev_handle != NULL);
+	assert(dev_handle != (uintptr_t)NULL);
 	assert(is_valid_dev(dev_handle));
 
-	io_dev_info_t *dev = dev_handle;
+	io_dev_info_t *dev = (io_dev_info_t *)dev_handle;
 
 	if (dev->funcs->dev_init != NULL) {
 		result = dev->funcs->dev_init(dev, init_params);
@@ -231,13 +232,13 @@ int io_dev_init(struct io_dev_info *dev_handle, const void *init_params)
 /* TODO: Consider whether an explicit "shutdown" API should be included */
 
 /* Close a connection to a device */
-int io_dev_close(io_dev_handle dev_handle)
+int io_dev_close(uintptr_t dev_handle)
 {
 	int result = IO_FAIL;
-	assert(dev_handle != NULL);
+	assert(dev_handle != (uintptr_t)NULL);
 	assert(is_valid_dev(dev_handle));
 
-	io_dev_info_t *dev = dev_handle;
+	io_dev_info_t *dev = (io_dev_info_t *)dev_handle;
 
 	if (dev->funcs->dev_close != NULL) {
 		result = dev->funcs->dev_close(dev);
@@ -254,13 +255,13 @@ int io_dev_close(io_dev_handle dev_handle)
 
 
 /* Open an IO entity */
-int io_open(io_dev_handle dev_handle, const void *spec, io_handle *handle)
+int io_open(uintptr_t dev_handle, const uintptr_t spec, uintptr_t *handle)
 {
 	int result = IO_FAIL;
-	assert((spec != NULL) && (handle != NULL));
+	assert((spec != (uintptr_t)NULL) && (handle != NULL));
 	assert(is_valid_dev(dev_handle));
 
-	io_dev_info_t *dev = dev_handle;
+	io_dev_info_t *dev = (io_dev_info_t *)dev_handle;
 	io_entity_t *entity;
 
 	result = allocate_entity(&entity);
@@ -270,7 +271,7 @@ int io_open(io_dev_handle dev_handle, const void *spec, io_handle *handle)
 		result = dev->funcs->open(dev, spec, entity);
 
 		if (result == IO_SUCCESS) {
-			entity->dev_handle = dev_handle;
+			entity->dev_handle = dev;
 			set_handle(handle, entity);
 		} else
 			free_entity(entity);
@@ -280,12 +281,12 @@ int io_open(io_dev_handle dev_handle, const void *spec, io_handle *handle)
 
 
 /* Seek to a specific position in an IO entity */
-int io_seek(io_handle handle, io_seek_mode_t mode, ssize_t offset)
+int io_seek(uintptr_t handle, io_seek_mode_t mode, ssize_t offset)
 {
 	int result = IO_FAIL;
 	assert(is_valid_entity(handle) && is_valid_seek_mode(mode));
 
-	io_entity_t *entity = handle;
+	io_entity_t *entity = (io_entity_t *)handle;
 
 	io_dev_info_t *dev = entity->dev_handle;
 
@@ -299,12 +300,12 @@ int io_seek(io_handle handle, io_seek_mode_t mode, ssize_t offset)
 
 
 /* Determine the length of an IO entity */
-int io_size(io_handle handle, size_t *length)
+int io_size(uintptr_t handle, size_t *length)
 {
 	int result = IO_FAIL;
 	assert(is_valid_entity(handle) && (length != NULL));
 
-	io_entity_t *entity = handle;
+	io_entity_t *entity = (io_entity_t *)handle;
 
 	io_dev_info_t *dev = entity->dev_handle;
 
@@ -318,12 +319,15 @@ int io_size(io_handle handle, size_t *length)
 
 
 /* Read data from an IO entity */
-int io_read(io_handle handle, void *buffer, size_t length, size_t *length_read)
+int io_read(uintptr_t handle,
+		uintptr_t buffer,
+		size_t length,
+		size_t *length_read)
 {
 	int result = IO_FAIL;
-	assert(is_valid_entity(handle) && (buffer != NULL));
+	assert(is_valid_entity(handle) && (buffer != (uintptr_t)NULL));
 
-	io_entity_t *entity = handle;
+	io_entity_t *entity = (io_entity_t *)handle;
 
 	io_dev_info_t *dev = entity->dev_handle;
 
@@ -337,13 +341,15 @@ int io_read(io_handle handle, void *buffer, size_t length, size_t *length_read)
 
 
 /* Write data to an IO entity */
-int io_write(io_handle handle, const void *buffer, size_t length,
+int io_write(uintptr_t handle,
+		const uintptr_t buffer,
+		size_t length,
 		size_t *length_written)
 {
 	int result = IO_FAIL;
-	assert(is_valid_entity(handle) && (buffer != NULL));
+	assert(is_valid_entity(handle) && (buffer != (uintptr_t)NULL));
 
-	io_entity_t *entity = handle;
+	io_entity_t *entity = (io_entity_t *)handle;
 
 	io_dev_info_t *dev = entity->dev_handle;
 
@@ -358,12 +364,12 @@ int io_write(io_handle handle, const void *buffer, size_t length,
 
 
 /* Close an IO entity */
-int io_close(io_handle handle)
+int io_close(uintptr_t handle)
 {
 	int result = IO_FAIL;
 	assert(is_valid_entity(handle));
 
-	io_entity_t *entity = handle;
+	io_entity_t *entity = (io_entity_t *)handle;
 
 	io_dev_info_t *dev = entity->dev_handle;
 
diff --git a/lib/semihosting/semihosting.c b/lib/semihosting/semihosting.c
index 1bce377c..3c9db221 100644
--- a/lib/semihosting/semihosting.c
+++ b/lib/semihosting/semihosting.c
@@ -48,7 +48,7 @@ typedef struct {
 
 typedef struct {
 	long handle;
-	void *buffer;
+	uintptr_t buffer;
 	size_t length;
 } smh_file_read_write_block_t;
 
@@ -96,12 +96,12 @@ long semihosting_file_seek(long file_handle, ssize_t offset)
 	return result;
 }
 
-long semihosting_file_read(long file_handle, size_t *length, void *buffer)
+long semihosting_file_read(long file_handle, size_t *length, uintptr_t buffer)
 {
 	smh_file_read_write_block_t read_block;
 	long result = -EINVAL;
 
-	if ((length == NULL) || (buffer == NULL))
+	if ((length == NULL) || (buffer == (uintptr_t)NULL))
 		return result;
 
 	read_block.handle = file_handle;
@@ -122,15 +122,15 @@ long semihosting_file_read(long file_handle, size_t *length, void *buffer)
 
 long semihosting_file_write(long file_handle,
 			    size_t *length,
-			    const void *buffer)
+			    const uintptr_t buffer)
 {
 	smh_file_read_write_block_t write_block;
 
-	if ((length == NULL) || (buffer == NULL))
+	if ((length == NULL) || (buffer == (uintptr_t)NULL))
 		return -EINVAL;
 
 	write_block.handle = file_handle;
-	write_block.buffer = (void *)buffer;
+	write_block.buffer = (uintptr_t)buffer; /* cast away const */
 	write_block.length = *length;
 
 	*length = semihosting_call(SEMIHOSTING_SYS_WRITE,
@@ -196,7 +196,7 @@ long semihosting_get_flen(const char *file_name)
 
 long semihosting_download_file(const char *file_name,
 			      size_t buf_size,
-			      void *buf)
+			      uintptr_t buf)
 {
 	long ret = -EINVAL;
 	size_t length;