Ignore:
Timestamp:
Jul 12, 2017, 8:12:41 PM (7 years ago)
Author:
alain
Message:

Redefine the PIC device API.

File:
1 edited

Legend:

Unmodified
Added
Removed

  • trunk/kernel/vfs/devfs.h

    r23 r188  
    2626#define _DEVFS_H_
    2727
    28 ///////////////////////////////////////////////////////////////////////////////////////////
    29 // The DEVFS File System contains inodes associated to all chdev descriptors availables
    30 // in the target architecture.  It is a three levels tree structure:
    31 // - The "dev" directory inode is stored in cluster_0. It is the root of the devfs
    32 //   file system. The parent inode is the "/" global root.
     28//////////////////////////////////////////////////////////////////////////////////////////
     29// The DEVFS File System contains inodes and dentries associated to all chdev descriptors
     30// availables in the architecture. It is structured as a three levels tree structure :
     31// - The "dev" directory inode is stored in cluster_IO. It is the root of the DEVFS
     32//   file system. The parent inode is the "/" VFS root.
    3333// - There is one "internal_cxy" directory inode per cluster, that is the parent of
    34 //   the local children inodes associated to the local chdev descriptors.
    35 //   The parent inode and dentry are stored in cluster_0.
     34//   the local children inodes associated to the local, internal chdev descriptors.
     35//   The parent dentry is stored in cluster_IO.
    3636// - The I/O cluster contains one "external" directory inode, that is the parent of
    37 //   the remote children inodes associated to the remote external descriptors.
    38 //   The parent inode and dentry are stored in cluster_0.
     37//   the remote children inodes associated to the remote external chdev descriptors.
     38//   The parent dentry is stored in cluster_IO.
    3939//
    40 // The DEVFS File system does not require a context extension, but requires an inode
    41 // extension to store the pointer on the associated chdev descriptor.
    42 ///////////////////////////////////////////////////////////////////////////////////////////
     40// The DEVFS file system uses the DEVFS context extension to register an extended pointer
     41// on the DEVFS "dev" inode, and and another extended pointer on the "external" inode.
     42//
     43// The DEVFS file system uses the VFS inode extension to store the pointer
     44// on the associated chdev descriptor.
     45//////////////////////////////////////////////////////////////////////////////////////////
    4346
    44 /**************  Forward declarations     ************************************************/
     47/*****************************************************************************************
     48 * This structure defines the DEVFS context extension.
     49 ****************************************************************************************/
    4550
    46 struct chdev_s;
    47 
    48 /******************************************************************************************
    49  * This structure defines the DEVFS inode descriptor extension.
    50  *****************************************************************************************/
    51 
    52 typedef struct devfs_inode_ext_s
     51typedef struct devfs_ctx_s
    5352{
    54     struct chdev_s * chdev;       /* extended pointer on associated chdev                */
     53    xptr_t   root_inode_xp;              /*! extended pointer on DEVFS root inode       */
     54    xptr_t   external_inode_xp;          /*! extended pointer on DEVFS external inode   */
    5555}
    56 devfs_inode_t;
     56devfs_ctx_t;
    5757
    5858
    59 
    60 
    61 
    62 //////////////////////////////////////////////////////////////////////////////////////////
    63 //                 These functions are called by the VFS.
    64 //////////////////////////////////////////////////////////////////////////////////////////
    65 
    66 /******************************************************************************************
    67  * This function  does not exist for the DEVFS file system, as this File System
    68  * cannot be mounted as the root FS.
    69  *****************************************************************************************/
    70 xptr_t devfs_init();
    71 
    72 
    73 /******************************************************************************************
    74  * This function mount the DEVFS file system on the root FS.
    75  * It is executed cooperatively during kernel init by all CP0s in all clusters,
    76  * to create the DEVFS 3-levels tree structure.
    77  * This is a four phases procedure, and it uses the global barrier to synchronize
    78  * the cooperating kernel instances when required.
    79  * - phase 1 : In all clusters, it creates the local extension of the DEVFS context,
    80  *    and initialises it.
    81  * - phase 2 : In cluster_0 only, it creates the dentry and the associated inode for
    82  *   the DEVFS root directory.
    83  * - phase 3 : In all cluster(x,y), it creates the dentry and the associated inode for
    84  *   the "internal_cxy" directory. It also creates the dentry and associated inode
    85  *   for all local internal chdevs.
    86  * - phase 4 : In cluster_io only, it creates the dentry and the associated inode
    87  *   for the "external" directory. It also creates the dentry and associated inode
    88  *   for all external chdevs.
    89  ******************************************************************************************
    90  * @ parent_inode_xp   : extended pointer on the parent inode in root FS.
    91  * @ devfs_root_name   : DEVFS root directory name.
    92  *****************************************************************************************/
    93 error_t devfs_mount( xptr_t   parent_inode_xp,
    94                      char   * devfs_root_name );
     59/*****************************************************************************************
     60 * This fuction allocates memory from local cluster for a DEVFS context descriptor.
     61 *****************************************************************************************
     62 * @ return a pointer on the created context / return NULL if failure.
     63 ****************************************************************************************/
     64devfs_ctx_t * devfs_ctx_alloc();
    9565
    9666/*****************************************************************************************
    97  * This function initializes all fields of the VFS context.
    98  * No extra memory is allocated for a DEVFS context.
     67 * This function initialises the DEVFS context from arguments values, and link it
     68 * to the relevant VFS context in the local cluster.
    9969 *****************************************************************************************
    100  * @ vfs_ctx        : local pointer on VFS context for FATFS.
    101  * @ root_inode_xp  : extended pointer on the VFS root inode.
     70 * @ devfs_ctx               : local pointer on DEVFS context.
     71 * @ devfs_root_inode_xp     : [out] extended pointer on created <dev> inode.
     72 * @ devfs_external_inode_xp : [out] extended pointer on created <external> inode.
    10273 ****************************************************************************************/
    103 error_t devfs_ctx_init( struct vfs_ctx_s * vfs_ctx,
    104                         xptr_t             root_inode_xp );
     74void devfs_ctx_init( devfs_ctx_t * devfs_ctx,
     75                     xptr_t        devfs_root_inode_xp,
     76                     xptr_t        devfs_external_inode_xp );
    10577
    10678/*****************************************************************************************
    107  * This function does not exist for a DEVFS context, as there is no DEVFS context.
     79 * This function releases memory dynamically allocated for the DEVFS context.
     80 *****************************************************************************************
     81 * @ devfs_ctx   : local pointer on DEVFS context.
    10882 ****************************************************************************************/
    109 error_t devfs_ctx_destroy();
     83void devfs_ctx_destroy( devfs_ctx_t * devfs_ctx );
    11084
    11185/*****************************************************************************************
    112  * This function allocates memory for a DEVFS inode, initialise it,
    113  * and link it to the VFS inode.
     86 * This function start to create the DEVFS subtree.
     87 * This function should be called once in the cluster containing the VFS parent inode.
     88 * More precisely, it creates in cluster IO the "dev" and "external" DEVFS directories.
     89 * For each one, it creates the inode and link the associated dentry to parent inode.
     90 * The DEVFS root inode is linked to the VFS parent inode identified by <parent_inode_xp>.
    11491 *****************************************************************************************
    115  * @ inode          : local pointer on the VFS inode.
    116  * @ chdev          : local pointer on the chdev to be inserted in DEVFS.
     92 * @ parent_inode_xp         : extended pointer on the parent VFS inode.
     93 * @ devfs_root_inode_xp     : [out] extended pointer on created <dev> inode.
     94 * @ devfs_external_inode_xp : [out] extended pointer on created <external> inode.
    11795 ****************************************************************************************/
    118 error_t devfs_inode_create( struct vfs_inode_s * inode,
    119                             struct chdev_s     * chdev );
     96void devfs_global_init( xptr_t   parent_inode_xp,
     97                        xptr_t * devfs_root_inode_xp,
     98                        xptr_t * devfs_external_inode_xp );
    12099
    121100/*****************************************************************************************
    122  * This function releases memory allocated for a DEVFS inode.
     101 * This function completes the initialisation of the DEVFS subtree.
     102 * It should be called once in each cluster.
     103 * 1. In each cluster (i), it creates the "internal" directory,
     104 *    linked to the DEVFS "dev" parent directory.
     105 * 2. In each cluster (i), it creates - for each external chdev in cluster (i) -
     106 *    a pseudo-file, linked to the DEVFS "external" parent directory.
     107 * 3. In each cluster (i), it creates - for each internal chdev in cluster (i) -
     108 *    a pseudo-file, linked to the DEVFS "internal" parent directory.
    123109 *****************************************************************************************
    124  * @ inode   : local pointer on vfs_inode.
     110 * @ devfs_root_inode_xp     : extended pointer on DEVFS root inode.
     111 * @ devfs_external_inode_xp : extended pointer on DEVFS external inode.
    125112 ****************************************************************************************/
    126 void devfs_inode_destroy( struct vfs_inode_s * inode );
    127 
    128 /*****************************************************************************************
    129  * This function does not exist for the DEVFS File System.
    130  ****************************************************************************************/
    131 error_t devfs_write_page( struct page_s * page );
    132 
    133 /*****************************************************************************************
    134  * This function does not exist for the DEVFS File System.
    135  ****************************************************************************************/
    136 error_t devfs_read_page( struct page_s * page );
    137 
    138 
    139 
     113void devfs_local_init( xptr_t devfs_root_inode_xp,
     114                       xptr_t devfs_external_inode_xp );
     115                       
    140116#endif  /* _DEVFS_H_ */
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