1 files changed, 328 insertions, 0 deletions
diff --git a/drivers/io/io_storage.c b/drivers/io/io_storage.c
new file mode 100644
index 0000000..0534268
--- /dev/null
+++ b/drivers/io/io_storage.c
@@ -0,0 +1,328 @@
+/*
+ * Copyright (c) 2014-2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <stddef.h>
+
+#include <platform_def.h>
+
+#include <drivers/io/io_driver.h>
+#include <drivers/io/io_storage.h>
+
+/* Storage for a fixed maximum number of IO entities, definable by platform */
+static io_entity_t entity_pool[MAX_IO_HANDLES];
+
+/* Simple way of tracking used storage - each entry is NULL or a pointer to an
+ * entity */
+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];
+
+/* Number of currently registered devices */
+static unsigned int dev_count;
+
+/* Extra validation functions only used when asserts are enabled */
+#if ENABLE_ASSERTIONS
+
+/* Return a boolean value indicating whether a device connector is valid */
+static bool is_valid_dev_connector(const io_dev_connector_t *dev_con)
+{
+	return (dev_con != NULL) && (dev_con->dev_open != NULL);
+}
+
+/* Return a boolean value indicating whether a device handle is valid */
+static bool is_valid_dev(const uintptr_t dev_handle)
+{
+	const io_dev_info_t *dev = (io_dev_info_t *)dev_handle;
+
+	return (dev != NULL) && (dev->funcs != NULL) &&
+			(dev->funcs->type != NULL) &&
+			(dev->funcs->type() < IO_TYPE_MAX);
+}
+
+
+/* Return a boolean value indicating whether an IO entity is valid */
+static bool is_valid_entity(const uintptr_t handle)
+{
+	const io_entity_t *entity = (io_entity_t *)handle;
+
+	return (entity != NULL) &&
+			(is_valid_dev((uintptr_t)entity->dev_handle));
+}
+
+
+/* Return a boolean value indicating whether a seek mode is valid */
+static bool is_valid_seek_mode(io_seek_mode_t mode)
+{
+	return ((mode != IO_SEEK_INVALID) && (mode < IO_SEEK_MAX));
+}
+
+#endif /* ENABLE_ASSERTIONS */
+/* End of extra validation functions only used when asserts are enabled */
+
+
+/* Open a connection to a specific device */
+static int io_storage_dev_open(const io_dev_connector_t *dev_con,
+		const uintptr_t dev_spec,
+		io_dev_info_t **dev_info)
+{
+	assert(dev_info != NULL);
+	assert(is_valid_dev_connector(dev_con));
+
+	return dev_con->dev_open(dev_spec, dev_info);
+}
+
+
+/* Set a handle to track an entity */
+static void set_handle(uintptr_t *handle, io_entity_t *entity)
+{
+	assert(handle != NULL);
+	*handle = (uintptr_t)entity;
+}
+
+
+/* Locate an entity in the pool, specified by address */
+static int find_first_entity(const io_entity_t *entity, unsigned int *index_out)
+{
+	int result = -ENOENT;
+	for (unsigned int index = 0; index < MAX_IO_HANDLES; ++index) {
+		if (entity_map[index] == entity) {
+			result = 0;
+			*index_out = index;
+			break;
+		}
+	}
+	return result;
+}
+
+
+/* Allocate an entity from the pool and return a pointer to it */
+static int allocate_entity(io_entity_t **entity)
+{
+	int result = -ENOMEM;
+	assert(entity != NULL);
+
+	if (entity_count < MAX_IO_HANDLES) {
+		unsigned int index = 0;
+		result = find_first_entity(NULL, &index);
+		assert(result == 0);
+		*entity = &entity_pool[index];
+		entity_map[index] = &entity_pool[index];
+		++entity_count;
+	}
+
+	return result;
+}
+
+
+/* Release an entity back to the pool */
+static int free_entity(const io_entity_t *entity)
+{
+	int result;
+	unsigned int index = 0;
+	assert(entity != NULL);
+
+	result = find_first_entity(entity, &index);
+	if (result ==  0) {
+		entity_map[index] = NULL;
+		--entity_count;
+	}
+
+	return result;
+}
+
+
+/* Exported API */
+
+/* Register a device driver */
+int io_register_device(const io_dev_info_t *dev_info)
+{
+	int result = -ENOMEM;
+	assert(dev_info != NULL);
+
+	if (dev_count < MAX_IO_DEVICES) {
+		devices[dev_count] = dev_info;
+		dev_count++;
+		result = 0;
+	}
+
+	return result;
+}
+
+
+/* Open a connection to an IO device */
+int io_dev_open(const io_dev_connector_t *dev_con, const uintptr_t dev_spec,
+		uintptr_t *handle)
+{
+	assert(handle != NULL);
+	return io_storage_dev_open(dev_con, dev_spec, (io_dev_info_t **)handle);
+}
+
+
+/* Initialise an IO device explicitly - to permit lazy initialisation or
+ * re-initialisation */
+int io_dev_init(uintptr_t dev_handle, const uintptr_t init_params)
+{
+	int result = 0;
+	assert(dev_handle != (uintptr_t)NULL);
+	assert(is_valid_dev(dev_handle));
+
+	io_dev_info_t *dev = (io_dev_info_t *)dev_handle;
+
+	/* Absence of registered function implies NOP here */
+	if (dev->funcs->dev_init != NULL) {
+		result = dev->funcs->dev_init(dev, init_params);
+	}
+
+	return result;
+}
+
+/* Close a connection to a device */
+int io_dev_close(uintptr_t dev_handle)
+{
+	int result = 0;
+	assert(dev_handle != (uintptr_t)NULL);
+	assert(is_valid_dev(dev_handle));
+
+	io_dev_info_t *dev = (io_dev_info_t *)dev_handle;
+
+	/* Absence of registered function implies NOP here */
+	if (dev->funcs->dev_close != NULL) {
+		result = dev->funcs->dev_close(dev);
+	}
+
+	return result;
+}
+
+
+/* Synchronous operations */
+
+
+/* Open an IO entity */
+int io_open(uintptr_t dev_handle, const uintptr_t spec, uintptr_t *handle)
+{
+	int result;
+	assert((spec != (uintptr_t)NULL) && (handle != NULL));
+	assert(is_valid_dev(dev_handle));
+
+	io_dev_info_t *dev = (io_dev_info_t *)dev_handle;
+	io_entity_t *entity;
+
+	result = allocate_entity(&entity);
+
+	if (result == 0) {
+		assert(dev->funcs->open != NULL);
+		result = dev->funcs->open(dev, spec, entity);
+
+		if (result == 0) {
+			entity->dev_handle = dev;
+			set_handle(handle, entity);
+		} else
+			free_entity(entity);
+	}
+	return result;
+}
+
+
+/* Seek to a specific position in an IO entity */
+int io_seek(uintptr_t handle, io_seek_mode_t mode, signed long long offset)
+{
+	int result = -ENODEV;
+	assert(is_valid_entity(handle) && is_valid_seek_mode(mode));
+
+	io_entity_t *entity = (io_entity_t *)handle;
+
+	io_dev_info_t *dev = entity->dev_handle;
+
+	if (dev->funcs->seek != NULL)
+		result = dev->funcs->seek(entity, mode, offset);
+
+	return result;
+}
+
+
+/* Determine the length of an IO entity */
+int io_size(uintptr_t handle, size_t *length)
+{
+	int result = -ENODEV;
+	assert(is_valid_entity(handle) && (length != NULL));
+
+	io_entity_t *entity = (io_entity_t *)handle;
+
+	io_dev_info_t *dev = entity->dev_handle;
+
+	if (dev->funcs->size != NULL)
+		result = dev->funcs->size(entity, length);
+
+	return result;
+}
+
+
+/* Read data from an IO entity */
+int io_read(uintptr_t handle,
+		uintptr_t buffer,
+		size_t length,
+		size_t *length_read)
+{
+	int result = -ENODEV;
+	assert(is_valid_entity(handle));
+
+	io_entity_t *entity = (io_entity_t *)handle;
+
+	io_dev_info_t *dev = entity->dev_handle;
+
+	if (dev->funcs->read != NULL)
+		result = dev->funcs->read(entity, buffer, length, length_read);
+
+	return result;
+}
+
+
+/* Write data to an IO entity */
+int io_write(uintptr_t handle,
+		const uintptr_t buffer,
+		size_t length,
+		size_t *length_written)
+{
+	int result = -ENODEV;
+	assert(is_valid_entity(handle));
+
+	io_entity_t *entity = (io_entity_t *)handle;
+
+	io_dev_info_t *dev = entity->dev_handle;
+
+	if (dev->funcs->write != NULL) {
+		result = dev->funcs->write(entity, buffer, length,
+				length_written);
+	}
+
+	return result;
+}
+
+
+/* Close an IO entity */
+int io_close(uintptr_t handle)
+{
+	int result = 0;
+	assert(is_valid_entity(handle));
+
+	io_entity_t *entity = (io_entity_t *)handle;
+
+	io_dev_info_t *dev = entity->dev_handle;
+
+	/* Absence of registered function implies NOP here */
+	if (dev->funcs->close != NULL)
+		result = dev->funcs->close(entity);
+
+	/* Ignore improbable free_entity failure */
+	(void)free_entity(entity);
+
+	return result;
+}