Bring IO storage dummy driver

Allow to handle cases where some images are pre-loaded (by debugger for
instance) without introducing many switches in files calling load_* functions.

Fixes: arm-software/tf-issues#398
Signed-off-by: Gerald Lejeune <gerald.lejeune@st.com>

drivers/io/io_dummy.c

+/*
+ * Copyright (c) 2016, 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 <debug.h>
+#include <io_driver.h>
+#include <io_storage.h>
+#include <string.h>
+
+struct file_state {
+	int in_use;
+	size_t size;
+};
+
+static struct file_state current_file = {0};
+
+/* Identify the device type as dummy */
+io_type_t device_type_dummy(void)
+{
+	return IO_TYPE_DUMMY;
+}
+
+/* Dummy device functions */
+static int dummy_dev_open(const uintptr_t dev_spec, io_dev_info_t **dev_info);
+static int dummy_block_open(io_dev_info_t *dev_info, const uintptr_t spec,
+			     io_entity_t *entity);
+static int dummy_block_len(io_entity_t *entity, size_t *length);
+static int dummy_block_read(io_entity_t *entity, uintptr_t buffer,
+			     size_t length, size_t *length_read);
+static int dummy_block_close(io_entity_t *entity);
+static int dummy_dev_close(io_dev_info_t *dev_info);
+
+
+static const io_dev_connector_t dummy_dev_connector = {
+	.dev_open = dummy_dev_open
+};
+
+
+static const io_dev_funcs_t dummy_dev_funcs = {
+	.type = device_type_dummy,
+	.open = dummy_block_open,
+	.seek = NULL,
+	.size = dummy_block_len,
+	.read = dummy_block_read,
+	.write = NULL,
+	.close = dummy_block_close,
+	.dev_init = NULL,
+	.dev_close = dummy_dev_close,
+};
+
+
+static const io_dev_info_t dummy_dev_info = {
+	.funcs = &dummy_dev_funcs,
+	.info = (uintptr_t)NULL
+};
+
+
+/* Open a connection to the dummy device */
+static int dummy_dev_open(const uintptr_t dev_spec __attribute__((unused)),
+			   io_dev_info_t **dev_info)
+{
+	assert(dev_info != NULL);
+	*dev_info = (io_dev_info_t *)&dummy_dev_info;
+
+	return 0;
+}
+
+
+/* Close a connection to the dummy device */
+static int dummy_dev_close(io_dev_info_t *dev_info)
+{
+	return 0;
+}
+
+
+/* Open a file on the dummy device */
+static int dummy_block_open(io_dev_info_t *dev_info, const uintptr_t spec,
+			     io_entity_t *entity)
+{
+	int result;
+	const io_block_spec_t *block_spec = (io_block_spec_t *)spec;
+
+	if (current_file.in_use == 0) {
+		assert(block_spec != NULL);
+		assert(entity != NULL);
+
+		current_file.in_use = 1;
+		current_file.size = block_spec->length;
+		entity->info = (uintptr_t)&current_file;
+		result = 0;
+	} else {
+		WARN("A Dummy device is already active. Close first.\n");
+		result = -ENOMEM;
+	}
+
+	return result;
+}
+
+
+/* Return the size of a file on the dummy device */
+static int dummy_block_len(io_entity_t *entity, size_t *length)
+{
+	assert(entity != NULL);
+	assert(length != NULL);
+
+	*length =  ((struct file_state *)entity->info)->size;
+
+	return 0;
+}
+
+
+/* Read data from a file on the dummy device */
+static int dummy_block_read(io_entity_t *entity, uintptr_t buffer,
+			     size_t length, size_t *length_read)
+{
+	assert(length_read != NULL);
+
+	*length_read = length;
+
+	return 0;
+}
+
+
+/* Close a file on the dummy device */
+static int dummy_block_close(io_entity_t *entity)
+{
+	assert(entity != NULL);
+
+	entity->info = 0;
+	current_file.in_use = 0;
+
+	return 0;
+}
+
+
+/* Exported functions */
+
+/* Register the dummy driver with the IO abstraction */
+int register_io_dev_dummy(const io_dev_connector_t **dev_con)
+{
+	int result;
+
+	assert(dev_con != NULL);
+
+	result = io_register_device(&dummy_dev_info);
+	if (result == 0)
+		*dev_con = &dummy_dev_connector;
+
+	return result;
+}

include/drivers/io/io_dummy.h

+/*
+ * Copyright (c) 2016, 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_DUMMY_H__
+#define __IO_DUMMY_H__
+
+int register_io_dev_dummy(const struct io_dev_connector **dev_con);
+
+#endif /* __IO_DUMMY_H__ */

include/drivers/io/io_storage.h

@@ -43,6 +43,7 @@ typedef enum {
 	IO_TYPE_INVALID,
 	IO_TYPE_SEMIHOSTING,
 	IO_TYPE_MEMMAP,
+	IO_TYPE_DUMMY,
 	IO_TYPE_FIRMWARE_IMAGE_PACKAGE,
 	IO_TYPE_MAX
 } io_type_t;