Implement load_image in terms of IO abstraction

The modified implementation uses the IO abstraction rather than
making direct semi-hosting calls.  The semi-hosting driver is now
registered for the FVP platform during initialisation of each boot
stage where it is used.  Additionally, the FVP platform includes a
straightforward implementation of 'plat_get_image_source' which
provides a generic means for the 'load_image' function to determine
how to access the image data.

Change-Id: Ia34457b471dbee990c7b3c79de7aee4ceea51aa6

2 files changed, 275 insertions, 0 deletions

diff --git a/drivers/io/io_semihosting.c b/drivers/io/io_semihosting.c
new file mode 100644
index 0000000..12d8315
--- /dev/null
+++ b/drivers/io/io_semihosting.c
@@ -0,0 +1,239 @@
+/*
+ * Copyright (c) 2014, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <assert.h>
+#include "io_storage.h"
+#include "io_driver.h"
+#include "semihosting.h"
+
+
+
+/* Identify the device type as semihosting */
+static io_type device_type_sh(void)
+{
+	return IO_TYPE_SEMIHOSTING;
+}
+
+
+/* Semi-hosting functions, device info and handle */
+
+static int sh_dev_open(void *spec, struct io_dev_info **dev_info);
+static int sh_file_open(struct io_dev_info *dev_info, const void *spec,
+		struct io_entity *entity);
+static int sh_file_seek(struct io_entity *entity, int mode, ssize_t offset);
+static int sh_file_len(struct io_entity *entity, size_t *length);
+static int sh_file_read(struct io_entity *entity, void *buffer, size_t length,
+		size_t *length_read);
+static int sh_file_write(struct io_entity *entity, const void *buffer,
+		size_t length, size_t *length_written);
+static int sh_file_close(struct io_entity *entity);
+
+static struct io_dev_connector sh_dev_connector = {
+	.dev_open = sh_dev_open
+};
+
+
+static struct io_dev_funcs sh_dev_funcs = {
+	.type = device_type_sh,
+	.open = sh_file_open,
+	.seek = sh_file_seek,
+	.size = sh_file_len,
+	.read = sh_file_read,
+	.write = sh_file_write,
+	.close = sh_file_close,
+	.dev_init = NULL,	/* NOP */
+	.dev_close = NULL,	/* NOP */
+};
+
+
+static struct io_dev_info sh_dev_info = {
+	.funcs = &sh_dev_funcs,
+	.info = (uintptr_t)NULL
+};
+
+
+/* Open a connection to the semi-hosting device */
+static int sh_dev_open(void *spec __unused, struct io_dev_info **dev_info)
+{
+	int result = IO_SUCCESS;
+	assert(dev_info != NULL);
+	*dev_info = &sh_dev_info;
+	return result;
+}
+
+
+/* Open a file on the semi-hosting device */
+static int sh_file_open(struct io_dev_info *dev_info __attribute__((unused)),
+		const void *spec, struct io_entity *entity)
+{
+	int result = IO_FAIL;
+	int sh_result = -1;
+	const io_file_spec *file_spec = (io_file_spec *)spec;
+
+	assert(file_spec != NULL);
+	assert(entity != NULL);
+
+	sh_result = semihosting_file_open(file_spec->path, file_spec->mode);
+
+	if (sh_result > 0) {
+		entity->info = sh_result;
+		result = IO_SUCCESS;
+	} else {
+		result = IO_FAIL;
+	}
+	return result;
+}
+
+
+/* Seek to a particular file offset on the semi-hosting device */
+static int sh_file_seek(struct io_entity *entity, int mode, ssize_t offset)
+{
+	int result = IO_FAIL;
+	int file_handle, sh_result;
+
+	assert(entity != NULL);
+
+	file_handle = (int)entity->info;
+
+	sh_result = semihosting_file_seek(file_handle, offset);
+
+	result = (sh_result == 0) ? IO_SUCCESS : IO_FAIL;
+
+	return result;
+}
+
+
+/* Return the size of a file on the semi-hosting device */
+static int sh_file_len(struct io_entity *entity, size_t *length)
+{
+	int result = IO_FAIL;
+
+	assert(entity != NULL);
+	assert(length != NULL);
+
+	int sh_handle = entity->info;
+	int sh_result = semihosting_file_length(sh_handle);
+
+	if (sh_result >= 0) {
+		result = IO_SUCCESS;
+		*length = (size_t)sh_result;
+	}
+
+	return result;
+}
+
+
+/* Read data from a file on the semi-hosting device */
+static int sh_file_read(struct io_entity *entity, void *buffer, size_t length,
+		size_t *length_read)
+{
+	int result = IO_FAIL;
+	int sh_result = -1;
+	int bytes = length;
+	int file_handle;
+
+	assert(entity != NULL);
+	assert(buffer != NULL);
+	assert(length_read != NULL);
+
+	file_handle = (int)entity->info;
+
+	sh_result = semihosting_file_read(file_handle, &bytes, buffer);
+
+	if (sh_result >= 0) {
+		*length_read = (bytes != length) ? bytes : length;
+		result = IO_SUCCESS;
+	} else
+		result = IO_FAIL;
+
+	return result;
+}
+
+
+/* Write data to a file on the semi-hosting device */
+static int sh_file_write(struct io_entity *entity, const void *buffer,
+		size_t length, size_t *length_written)
+{
+	int result = IO_FAIL;
+	int sh_result = -1;
+	int file_handle;
+	int bytes = length;
+
+	assert(entity != NULL);
+	assert(buffer != NULL);
+	assert(length_written != NULL);
+
+	file_handle = (int)entity->info;
+
+	sh_result = semihosting_file_write(file_handle, &bytes, buffer);
+
+	if (sh_result >= 0) {
+		*length_written = sh_result;
+		result = IO_SUCCESS;
+	} else
+		result = IO_FAIL;
+
+	return result;
+}
+
+
+/* Close a file on the semi-hosting device */
+static int sh_file_close(struct io_entity *entity)
+{
+	int result = IO_FAIL;
+	int sh_result = -1;
+	int file_handle;
+
+	assert(entity != NULL);
+
+	file_handle = (int)entity->info;
+
+	sh_result = semihosting_file_close(file_handle);
+
+	result = (sh_result >= 0) ? IO_SUCCESS : IO_FAIL;
+
+	return result;
+}
+
+
+/* Exported functions */
+
+/* Register the semi-hosting driver with the IO abstraction */
+int register_io_dev_sh(struct io_dev_connector **dev_con)
+{
+	int result = IO_FAIL;
+	assert(dev_con != NULL);
+
+	result = io_register_device(&sh_dev_info);
+	if (result == IO_SUCCESS)
+		*dev_con = &sh_dev_connector;
+
+	return result;
+}
diff --git a/drivers/io/io_semihosting.h b/drivers/io/io_semihosting.h
new file mode 100644
index 0000000..7dc632d
--- /dev/null
+++ b/drivers/io/io_semihosting.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2014, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __IO_SH_H__
+#define __IO_SH_H__
+
+int register_io_dev_sh(struct io_dev_connector **dev_con);
+
+#endif /* __IO_SH_H__ */