FreeBSD/Linux Kernel Cross Reference
sys/dev/bhnd/nvram/bhnd_nvram_io.c

     /*-
      * Copyright (c) 2016 Landon Fuller <landonf@FreeBSD.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer,
     *    without modification.
     * 2. Redistributions in binary form must reproduce at minimum a disclaimer
     *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
     *    redistribution must be conditioned upon including a substantially
     *    similar Disclaimer requirement for further binary redistribution.
     *
     * NO WARRANTY
     * 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 NONINFRINGEMENT, MERCHANTIBILITY
     * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
     * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #ifdef _KERNEL
    #include <sys/param.h>
    #else /* !_KERNEL */
    #include <errno.h>
    #include <stdint.h>
    #include <stdlib.h>
    #endif /* _KERNEL */
    
    #include "bhnd_nvram_io.h"
    #include "bhnd_nvram_iovar.h"
    
    /**
     * Read exactly @p nbytes from @p io at @p offset.
     *
     * @param io NVRAM I/O context.
     * @param offset The offset within @p io at which to perform the read.
     * @param[out] buffer Output buffer to which @p nbytes from @p io will be
     * written.
     * @param nbytes The maximum number of bytes to be read from @p io.
     *
     * @retval 0 success
     * @retval EIO if an input error occurred reading @p io.
     * @retval ENXIO if the request for @p offset or @p nbytes exceeds the size
     * of @p io.
     * @retval EFAULT if @p io requires I/O request alignment and @p offset is
     * misaligned.
     * @retval EFAULT if @p io requires I/O request alignment and @p nbytes is
     * misaligned and cannot be rounded down to an aligned non-zero value.
     */
    int
    bhnd_nvram_io_read(struct bhnd_nvram_io *io, size_t offset, void *buffer,
        size_t nbytes)
    {
            return (io->iops->read(io, offset, buffer, nbytes));
    }
    
    /**
     * Attempt to fetch a pointer to @p io's internal read buffer, if
     * supported by @p io.
     *
     * The returned pointer is only gauranteed to be valid until the next I/O
     * operation performed on @p io; concrete implementations of bhnd_nvram_io
     * may provide stronger gaurantees.
     *
     * @param io NVRAM I/O context.
     * @param offset The offset within @p io for which to return a buffer pointer.
     * @param[out] ptr On success, will be initialized with a pointer to @p io's
     * internal read buffer.
     * @param nbytes The minimum number of bytes that must be readable at @p offset.
     * @param[out] navail The actual number of readable bytes, which may be greater
     * than @p nbytes. If this value is not required, a NULL pointer may be
     * provided.
     *
     * @retval 0 success
     * @retval EIO if an input error occurred reading @p io.
     * @retval ENODEV if @p io does not support direct access to its backing read
     * buffer.
     * @retval ENXIO if the request exceeds the size of @p io.
     * @retval EFAULT if @p io requires I/O request alignment and @p offset or
     * @p nbytes are misaligned.
     */
    int
    bhnd_nvram_io_read_ptr(struct bhnd_nvram_io *io, size_t offset,
        const void **ptr, size_t nbytes, size_t *navail)
    {
            return (io->iops->read_ptr(io, offset, ptr, nbytes, navail));
    }
   
   /**
    * Write @p nbytes to @p io at @p offset.
    *
    * @param io NVRAM I/O context.
    * @param offset The offset within @p io at which to perform the write.
    * @param buffer Data to be written to @p io.
    * @param nbytes The number of bytes to be written from @p buffer.
    * 
    * @retval 0 success
    * @retval EIO if an output error occurs writing to @p io.
    * @retval ENODEV if @p io does not support writing.
    * @retval ENXIO if @p io does not support writes beyond the existing
    * end-of-file, and a write at @p offset would exceed the size of the @p io
    * backing data store.
    * @retval EFAULT if @p io requires I/O request alignment and @p offset or
    * @p nbytes are misaligned.
    */
   int
   bhnd_nvram_io_write(struct bhnd_nvram_io *io, size_t offset, void *buffer,
       size_t nbytes)
   {
           return (io->iops->write(io, offset, buffer, nbytes));
   }
   
   /**
    * Attempt to fetch a writable pointer to @p io's internal write buffer, if
    * supported by @p io.
    *
    * The returned pointer is only gauranteed to be valid until the next I/O
    * operation performed on @p io; concrete implementations of bhnd_nvram_io
    * may provide stronger gaurantees.
    * 
    * @param io NVRAM I/O context.
    * @param offset The offset within @p io for which to return a buffer pointer.
    * @param[in,out] ptr On success, will be initialized with a pointer to @p io's
    * internal buffer at which up to @p nbytes may be written.
    * @param nbytes The minimum number of bytes that must be writable at @p offset.
    * @param[out] navail The actual number of writable bytes, which may be greater
    * than @p nbytes. If this value is not required, a NULL pointer may be
    * provided.
    * 
    * @retval 0 success
    * @retval EIO if an output error occurs preparing @p io's write buffer.
    * @retval ENODEV if @p io does not support direct access to its backing write
    * buffer.
    * @retval ENXIO if @p io does not support writes beyond the existing
    * end-of-file, and a write at @p offset of @p nbytes would exceed the size of
    * the @p io backing data store.
    * @retval EFAULT if @p io requires I/O request alignment and @p offset or
    * @p nbytes are misaligned.
    */
   int
   bhnd_nvram_io_write_ptr(struct bhnd_nvram_io *io, size_t offset, void **ptr,
       size_t nbytes, size_t *navail)
   {
           return (io->iops->write_ptr(io, offset, ptr, nbytes, navail));
   }
   
   /**
    * Return the total number of bytes readable via @p io.
    * 
    * @param io NVRAM I/O context.
    */
   size_t
   bhnd_nvram_io_getsize(struct bhnd_nvram_io *io)
   {
           return (io->iops->getsize(io));
   }
   
   /**
    * Attempt to set the size of @p io to @p size.
    *
    * If the total size of @p io is increased, the contents of the newly mapped
    * bytes are undefined; concrete implementations of bhnd_nvram_io may
    * provide stronger gaurantees.
    *
    * @param io NVRAM I/O context.
    * @param size The new size.
    *
    * @retval 0 success
    * @retval EIO if an I/O error occurs resizing @p io.
    * @retval ENODEV if @p io does not support resizing.
    * @retval ENXIO if @p size exceeds the capacity or other limits of @p io.
    * @retval EFAULT if @p io requires I/O request alignment and @p size is
    * misaligned.
    */
   int
   bhnd_nvram_io_setsize(struct bhnd_nvram_io *io, size_t size)
   {
           return (io->iops->setsize(io, size));
   }
   
   /**
    * Free a previously allocated I/O context, releasing all associated
    * resources.
    *
    * @param io The I/O context to be freed.
    */
   void
   bhnd_nvram_io_free(struct bhnd_nvram_io *io)
   {
           return (io->iops->free(io));
   }

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