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-rw-r--r--drivers/io/io_memmap.c240
1 files changed, 240 insertions, 0 deletions
diff --git a/drivers/io/io_memmap.c b/drivers/io/io_memmap.c
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+++ b/drivers/io/io_memmap.c
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+/*
+ * 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 <string.h>
+#include "io_storage.h"
+#include "io_driver.h"
+#include "debug.h"
+
+/* As we need to be able to keep state for seek, only one file can be open
+ * at a time. Make this a structure and point to the entity->info. When we
+ * can malloc memory we can change this to support more open files.
+ */
+typedef struct {
+ /* Use the 'in_use' flag as any value for base and file_pos could be
+ * valid.
+ */
+ int in_use;
+ size_t base;
+ size_t file_pos;
+} file_state;
+
+static file_state current_file = {0};
+
+/* Identify the device type as memmap */
+io_type device_type_memmap(void)
+{
+ return IO_TYPE_MEMMAP;
+}
+
+/* Memmap device functions */
+static int memmap_dev_open(void *spec, struct io_dev_info **dev_info);
+static int memmap_block_open(struct io_dev_info *dev_info, const void *spec,
+ struct io_entity *entity);
+static int memmap_block_seek(struct io_entity *entity, int mode,
+ ssize_t offset);
+static int memmap_block_read(struct io_entity *entity, void *buffer,
+ size_t length, size_t *length_read);
+static int memmap_block_write(struct io_entity *entity, const void *buffer,
+ size_t length, size_t *length_written);
+static int memmap_block_close(struct io_entity *entity);
+static int memmap_dev_close(struct io_dev_info *dev_info);
+
+
+static struct io_dev_connector memmap_dev_connector = {
+ .dev_open = memmap_dev_open
+};
+
+
+static struct io_dev_funcs memmap_dev_funcs = {
+ .type = device_type_memmap,
+ .open = memmap_block_open,
+ .seek = memmap_block_seek,
+ .size = NULL,
+ .read = memmap_block_read,
+ .write = memmap_block_write,
+ .close = memmap_block_close,
+ .dev_init = NULL,
+ .dev_close = memmap_dev_close,
+};
+
+
+static struct io_dev_info memmap_dev_info = {
+ .funcs = &memmap_dev_funcs,
+ .info = (uintptr_t)NULL
+};
+
+
+/* Open a connection to the memmap device */
+static int memmap_dev_open(void *spec __attribute__((unused)),
+ struct io_dev_info **dev_info)
+{
+ assert(dev_info != NULL);
+ *dev_info = &memmap_dev_info;
+
+ return IO_SUCCESS;
+}
+
+
+
+/* Close a connection to the memmap device */
+static int memmap_dev_close(struct io_dev_info *dev_info)
+{
+ /* NOP */
+ /* TODO: Consider tracking open files and cleaning them up here */
+ return IO_SUCCESS;
+}
+
+
+/* Open a file on the memmap device */
+/* TODO: Can we do any sensible limit checks on requested memory */
+static int memmap_block_open(struct io_dev_info *dev_info, const void *spec,
+ struct io_entity *entity)
+{
+ int result = IO_FAIL;
+ const io_block_spec *block_spec = (io_block_spec *)spec;
+
+ /* Since we need to track open state for seek() we only allow one open
+ * spec at a time. When we have dynamic memory we can malloc and set
+ * entity->info.
+ */
+ if (current_file.in_use == 0) {
+ assert(block_spec != NULL);
+ assert(entity != NULL);
+
+ current_file.in_use = 1;
+ current_file.base = block_spec->offset;
+ /* File cursor offset for seek and incremental reads etc. */
+ current_file.file_pos = 0;
+ entity->info = (uintptr_t)&current_file;
+ result = IO_SUCCESS;
+ } else {
+ ERROR("A Memmap device is already active. Close first.\n");
+ result = IO_RESOURCES_EXHAUSTED;
+ }
+
+ return result;
+}
+
+
+/* Seek to a particular file offset on the memmap device */
+static int memmap_block_seek(struct io_entity *entity, int mode, ssize_t offset)
+{
+ int result = IO_FAIL;
+
+ /* We only support IO_SEEK_SET for the moment. */
+ if (mode == IO_SEEK_SET) {
+ assert(entity != NULL);
+
+ /* TODO: can we do some basic limit checks on seek? */
+ ((file_state *)entity->info)->file_pos = offset;
+ result = IO_SUCCESS;
+ } else {
+ result = IO_FAIL;
+ }
+
+ return result;
+}
+
+
+/* Read data from a file on the memmap device */
+static int memmap_block_read(struct io_entity *entity, void *buffer,
+ size_t length, size_t *length_read)
+{
+ file_state *fp;
+
+ assert(entity != NULL);
+ assert(buffer != NULL);
+ assert(length_read != NULL);
+
+ fp = (file_state *)entity->info;
+
+ memcpy(buffer, (void *)(fp->base + fp->file_pos), length);
+
+ *length_read = length;
+ /* advance the file 'cursor' for incremental reads */
+ fp->file_pos += length;
+
+ return IO_SUCCESS;
+}
+
+
+/* Write data to a file on the memmap device */
+static int memmap_block_write(struct io_entity *entity, const void *buffer,
+ size_t length, size_t *length_written)
+{
+ file_state *fp;
+
+ assert(entity != NULL);
+ assert(buffer != NULL);
+ assert(length_written != NULL);
+
+ fp = (file_state *)entity->info;
+
+ memcpy((void *)(fp->base + fp->file_pos), buffer, length);
+
+ *length_written = length;
+
+ /* advance the file 'cursor' for incremental writes */
+ fp->file_pos += length;
+
+ return IO_SUCCESS;
+}
+
+
+/* Close a file on the memmap device */
+static int memmap_block_close(struct io_entity *entity)
+{
+ assert(entity != NULL);
+
+ entity->info = 0;
+
+ /* This would be a mem free() if we had malloc.*/
+ memset((void *)&current_file, 0, sizeof(current_file));
+
+ return IO_SUCCESS;
+}
+
+
+/* Exported functions */
+
+/* Register the memmap driver with the IO abstraction */
+int register_io_dev_memmap(struct io_dev_connector **dev_con)
+{
+ int result = IO_FAIL;
+ assert(dev_con != NULL);
+
+ result = io_register_device(&memmap_dev_info);
+ if (result == IO_SUCCESS)
+ *dev_con = &memmap_dev_connector;
+
+ return result;
+}