2009-04-29 Sebastian Huber <sebastian.huber@embedded-brains.de>

        * sapi/include/confdefs.h, libblock/include/rtems/bdbuf.h: Changed
        type of rtems_bdbuf_pool_configuration_size to size_t.

        * libblock/include/rtems/bdbuf.h, libblock/include/rtems/blkdev.h,
        libblock/include/rtems/diskdevs.h, libblock/src/bdbuf.c,
        libblock/src/blkdev.c, libblock/src/diskdevs.c: Buffer pool
        allocation is now cache aligned.  The cache functions are
        currently not available on all platforms so the cache line size is
        fixed to 32 bytes for now.  Changed various integer types which
        refer to block sizes, numbers and indexes.  Fixed logical block
        indexes in buffer get and read function.  It is now possible to
        delete logical disks.  Modified documentation

1 files changed, 178 insertions, 162 deletions

diff --git a/cpukit/libblock/include/rtems/diskdevs.h b/cpukit/libblock/include/rtems/diskdevs.h
index af56f720a0..da5c32ec13 100644
--- a/cpukit/libblock/include/rtems/diskdevs.h
+++ b/cpukit/libblock/include/rtems/diskdevs.h
@@ -1,6 +1,7 @@
 /**
- * @file rtems/diskdevs.h
- * Physical and logical block devices (disks) support
+ * @file
+ *
+ * Block device disk management.
  */
  
 /*
@@ -13,197 +14,212 @@
 #ifndef _RTEMS_DISKDEVS_H
 #define _RTEMS_DISKDEVS_H
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 #include <rtems.h>
 #include <rtems/libio.h>
 #include <stdlib.h>
 
-/* Buffer pool identifier */
+/**
+ * @ingroup rtems_bdbuf
+ *
+ * Buffer pool identifier.
+ */
 typedef int rtems_bdpool_id;
 
 #include <rtems/blkdev.h>
 
-/* Driver capabilities. */
+#ifdef __cplusplus
+extern "C" {
+#endif
 
-/* Block device ioctl handler */
-typedef int (* rtems_block_device_ioctl) (dev_t dev, uint32_t req, void *argp);
+/**
+ * @defgroup rtems_disk Block Device Disk Management
+ *
+ * @ingroup rtems_libblock
+ *
+ * This module provides functions to manage disk devices.  The disk devices are
+ * accessed via the RTEMS block device library.  A disk is a set of blocks
+ * which are identified by a consecutive set of non-negative integers starting
+ * at zero.  There are also logical disks which contain a subset of consecutive
+ * disk blocks.  The logical disks are used to represent the partitions of a
+ * disk.
+ *
+ * @{
+ */
 
-/* rtems_disk_device: Entry of this type created for every disk device
- * (both for logical and physical disks).
- * Array of arrays of pointers to disk_device structures maintained. First
- * table indexed by major number and second table indexed by minor number.
- * Such data organization allow quick lookup using data structure of
- * moderated size.
+/**
+ * Block device IO control handler type.
+ */
+typedef int (*rtems_block_device_ioctl)( dev_t dev, uint32_t req, void *argp);
+
+/**
+ * Description of a disk device (logical and physical disks).
+ *
+ * An array of pointer tables to rtems_disk_device structures is maintained.
+ * The first table will be indexed by the major number and the second table
+ * will be indexed by the minor number.  This allows quick lookup using a data
+ * structure of moderated size.
  */
 typedef struct rtems_disk_device {
-    dev_t                     dev;          /* Device ID (major + minor) */
-    struct rtems_disk_device *phys_dev;     /* Physical device ID (the same
-                                               as dev if this entry specifies
-                                               the physical device) */
-    uint32_t                  capabilities; /* Driver capabilities. */
-    char                     *name;         /* Disk device name */
-    int                       uses;         /* Use counter. Device couldn't be
-                                               removed if it is in use. */
-    uint32_t                  start;        /* Starting block number (0 for
-                                               physical devices, block offset
-                                               on the related physical device
-                                               for logical device) */
-    uint32_t                  size;         /* Size of physical or logical disk
-                                               in disk blocks */
-    uint32_t                  block_size;   /* Size of device block (minimum
-                                               transfer unit) in bytes
-                                               (must be power of 2) */
-    uint32_t            block_size_log2;    /* log2 of block_size */
-    rtems_bdpool_id     pool;               /* Buffer pool assigned to this
-                                               device */
-    rtems_block_device_ioctl  ioctl;        /* ioctl handler for this block
-                                               device */
+  /**
+   * Device identifier (concatenation of major and minor number).
+   */
+  dev_t dev;
+
+  /**
+   * Physical device identifier (equals the @c dev entry if it specifies a
+   * physical device).
+   */
+  struct rtems_disk_device *phys_dev;
+
+  /**
+   * Driver capabilities.
+   */
+  uint32_t capabilities;
+
+  /**
+   * Disk device name.
+   */
+  char *name;
+
+  /**
+   * Usage counter.
+   *
+   * Devices cannot be removed if they are in use.
+   */
+  unsigned uses;
+
+  /**
+   * Start block number.
+   *
+   * Equals zero for physical devices.  It is a block offset to the related
+   * physical device for logical device.
+   */
+  rtems_blkdev_bnum start;
+
+  /**
+   * Size of the physical or logical disk in blocks.
+   */
+  rtems_blkdev_bnum size;
+
+  /**
+   * Device block size in bytes.
+   *
+   * This is the minimum transfer unit and must be power of two.
+   */
+  uint32_t block_size;
+
+  /**
+   * Binary logarithm of the block size.
+   */
+  uint32_t block_size_log2;
+
+  /**
+   * Buffer pool assigned to this disk.
+   */
+  rtems_bdpool_id pool;
+
+  /**
+   * IO control handler for this disk.
+   */
+  rtems_block_device_ioctl ioctl;
 } rtems_disk_device;
 
-/* rtems_disk_create_phys --
- *     Create physical disk entry. This function usually invoked from
- *     block device driver initialization code when physical device
- *     detected in the system. Device driver should provide ioctl handler
- *     to allow block device access operations. This primitive will register
- *     device in rtems (invoke rtems_io_register_name).
- *
- * PARAMETERS:
- *     dev        - device identifier (major, minor numbers)
- *     block_size - size of disk block (minimum data transfer unit); must be
- *                  power of 2
- *     disk_size  - number of blocks on device
- *     handler    - IOCTL handler (function providing basic block input/output
- *                  request handling BIOREQUEST and other device management
- *                  operations)
- *     name       - character name of device (e.g. /dev/hda)
- *
- * RETURNS:
- *     RTEMS_SUCCESSFUL if information about new physical disk added, or
- *     error code if error occured (device already registered, wrong block
- *     size value, no memory available).
- */
-rtems_status_code
-rtems_disk_create_phys(dev_t dev, int block_size, int disk_size,
-                       rtems_block_device_ioctl handler,
-                       const char *name);
-
-/* rtems_disk_create_log --
- *     Create logical disk entry. Logical disk is contiguous area on physical
- *     disk. Disk may be splitted to several logical disks in several ways:
- *     manually or using information stored in blocks on physical disk
- *     (DOS-like partition table, BSD disk label, etc). This function usually
- *     invoked from application when application-specific splitting are in use,
- *     or from generic code which handle different logical disk organizations.
- *     This primitive will register device in rtems (invoke
- *     rtems_io_register_name).
- *
- * PARAMETERS:
- *     dev   - logical device identifier (major, minor numbers)
- *     phys  - physical device (block device which holds this logical disk)
- *             identifier
- *     start - starting block number on the physical device
- *     size  - logical disk size in blocks
- *     name  - logical disk name
- *
- * RETURNS:
- *     RTEMS_SUCCESSFUL if logical device successfully added, or error code
- *     if error occured (device already registered, no physical device
- *     exists, logical disk is out of physical disk boundaries, no memory
- *     available).
+/**
+ * Creates a physical disk with device identifier @a dev.
+ *
+ * The block size @a block_size must be a power of two.  The disk size @a
+ * disk_size is the number of blocks provided by this disk.  The block index
+ * starts with zero.  The associated disk device driver will be invoked via the
+ * IO control handler @a handler.  A device node will be registered in the file
+ * system with absolute path @a name.  This function is usually invoked from a
+ * block device driver during initialization when a physical device is detected
+ * in the system.  The device driver provides an IO control handler to allow
+ * block device operations.
  */
-rtems_status_code
-rtems_disk_create_log(dev_t dev, dev_t phys, int start, int size, char *name);
-
-/* rtems_disk_delete --
- *     Delete physical or logical disk device. Device may be deleted if its
- *     use counter (and use counters of all logical devices - if it is
- *     physical device) equal to 0. When physical device deleted,
- *     all logical devices deleted inherently. Appropriate devices removed
- *     from "/dev" filesystem.
- *
- * PARAMETERS:
- *     dev - device identifier (major, minor numbers)
- *
- * RETURNS:
- *     RTEMS_SUCCESSFUL if block device successfully deleted, or error code
- *     if error occured (device is not defined, device is in use).
+rtems_status_code rtems_disk_create_phys(
+  dev_t dev,
+  uint32_t block_size,
+  rtems_blkdev_bnum disk_size,
+  rtems_block_device_ioctl handler,
+  const char *name
+);
+
+/**
+ * Creates a logical disk with device identifier @a dev.
+ *
+ * A logical disk manages a subset of consecutive blocks containd in the
+ * physical disk with identifier @a phys.  The start block index of the logical
+ * disk device is @a start.  The block number of the logcal disk will be @a
+ * size.  The blocks must be within the range of blocks managed by the
+ * associated physical disk device.  A device node will be registered in the
+ * file system with absolute path @a name.  The block size and IO control
+ * handler are inherited by the physical disk.
  */
-rtems_status_code
-rtems_disk_delete(dev_t dev);
+rtems_status_code rtems_disk_create_log(
+  dev_t dev,
+  dev_t phys,
+  rtems_blkdev_bnum start,
+  rtems_blkdev_bnum size,
+  const char *name
+);
 
-/* rtems_disk_obtain --
- *     Find block device descriptor by its device identifier. This function
- *     increment usage counter to 1. User should release disk_device structure
- *     by invoking rtems_disk_release primitive.
- *
- * PARAMETERS:
- *     dev - device identifier (major, minor numbers)
+/**
+ * Deletes a physical or logical disk device with identifier @a dev.
  *
- * RETURNS:
- *     pointer to the block device descriptor, or NULL if no such device
- *     exists.
+ * Disk devices may be deleted if there usage counter (and the usage counters
+ * of all contained logical disks devices) equals zero.  When a physical disk
+ * device is deleted, all logical disk devices will deleted too.  The
+ * corresponding device nodes will be removed from the file system.
  */
-rtems_disk_device *
-rtems_disk_obtain(dev_t dev);
+rtems_status_code rtems_disk_delete(dev_t dev);
 
-/* rtems_disk_release --
- *     Release disk_device structure (decrement usage counter to 1).
- *
- * PARAMETERS:
- *     dd - pointer to disk device structure
- *
- * RETURNS:
- *     RTEMS_SUCCESSFUL
+/**
+ * Returns the disk device descriptor for the device identifier @a dev.
  *
- * NOTE:
- *     It should be implemented as inline function.
+ * Increments usage counter by one.  You should release the disk device
+ * descriptor with rtems_disk_release().  Returns @c NULL if no corresponding
+ * disk exists.
  */
-rtems_status_code
-rtems_disk_release(rtems_disk_device *dd);
+rtems_disk_device *rtems_disk_obtain(dev_t dev);
 
-/* rtems_disk_next --
- *     Disk device enumerator. Looking for device having device number larger
- *     than dev and return disk device descriptor for it. If there are no
- *     such device, NULL value returned.
- *
- * PARAMETERS:
- *     dev - device number (use -1 to start search)
+/**
+ * Releases the disk device description @a dd.
  *
- * RETURNS:
- *     Pointer to the disk descriptor for next disk device, or NULL if all
- *     devices enumerated. */
-rtems_disk_device *
-rtems_disk_next(dev_t dev);
+ * Decrements usage counter by one.
+ */
+rtems_status_code rtems_disk_release(rtems_disk_device *dd);
 
-/* rtems_diskio_initialize --
- *     Initialization of disk device library (initialize all data structures,
- *     etc.)
+/**
+ * Disk device iterator.
  *
- * PARAMETERS:
- *     none
+ * Returns the next disk device descriptor with a device identifier larger than
+ * @a dev.  If there is no such device, @c NULL will be returned.  Use minus
+ * one to start the search.
  *
- * RETURNS:
- *     RTEMS_SUCCESSFUL if library initialized, or error code if error
- *     occured.
+ * @code
+ * rtems_disk_device *dd = rtems_disk_next((dev_t) -1);
+ *
+ * while (dd != NULL) {
+ *   dd = rtems_disk_next(dd->dev);
+ * }
+ * @endcode
  */
-rtems_status_code
-rtems_disk_io_initialize(void);
+rtems_disk_device *rtems_disk_next(dev_t dev);
 
-/* rtems_diskio_done --
- *     Release all resources allocated for disk device interface.
- *
- * PARAMETERS:
- *     none
+/**
+ * Initializes the disk device management.
  *
- * RETURNS:
- *     RTEMS_SUCCESSFUL if all resources released, or error code if error
- *     occured.
+ * This functions returns successful if the disk device management is already
+ * initialized.  There is no protection against concurrent access.
  */
-rtems_status_code
-rtems_disk_io_done(void);
+rtems_status_code rtems_disk_io_initialize(void);
+
+/**
+ * Releases all resources allocated for disk device management.
+ */
+rtems_status_code rtems_disk_io_done(void);
+
+/** @} */
 
 #ifdef __cplusplus
 }