/* * devfs.h - DEVFS File System API definition * * Authors Mohamed Lamine Karaoui (2014,2015) * Alain Greiner (2016,2017) * * Copyright (c) 2011,2012 UPMC Sorbonne Universites * * This file is part of ALMOS-MKH. * * ALMOS-MKH is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2.0 of the License. * * ALMOS-MKH is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with ALMOS-MKH; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef _DEVFS_H_ #define _DEVFS_H_ ////////////////////////////////////////////////////////////////////////////////////////// // The DEVFS File System contains inodes and dentries associated to all chdev descriptors // availables in the architecture. // // It is structured as a three levels tree structure : // - The "dev" directory inode is stored in cluster_IO. It is the root of the DEVFS // file system. The parent inode is the "/" VFS root. // - There is one "internal_cxy" directory inode per cluster, that is the parent of // the local children inodes associated to the local, internal chdev descriptors. // The parent dentry is stored in cluster_IO. // - The I/O cluster contains one "external" directory inode, that is the parent of // the remote children inodes associated to the remote external chdev descriptors. // The parent dentry is stored in cluster_IO. // // The DEVFS extensions to the generic VFS are the following: // 1) The vfs_ctx_t "extend" void* field is pointing on the devfs_ctx_t structure. // This structure contains two extended pointers on the DEVFS "dev" directory inode, // and on the "external" directory inode. // 2) The vfs_inode_t "extend" void* field is pointing on the chdev descriptor. ////////////////////////////////////////////////////////////////////////////////////////// /***************************************************************************************** * This structure defines the DEVFS context extension. ****************************************************************************************/ typedef struct devfs_ctx_s { xptr_t dev_inode_xp; /*! extended pointer on DEVFS root inode */ xptr_t external_inode_xp; /*! extended pointer on DEVFS external inode */ } devfs_ctx_t; /***************************************************************************************** * This fuction allocates memory from local cluster for a DEVFS context descriptor. ***************************************************************************************** * @ return a pointer on the created context / return NULL if failure. ****************************************************************************************/ devfs_ctx_t * devfs_ctx_alloc(); /***************************************************************************************** * This function initialises the DEVFS context from arguments values, and link it * to the relevant VFS context in the local cluster. ***************************************************************************************** * @ devfs_ctx : local pointer on DEVFS context. * @ devfs_dev_inode_xp : [out] extended pointer on inode. * @ devfs_external_inode_xp : [out] extended pointer on inode. ****************************************************************************************/ void devfs_ctx_init( devfs_ctx_t * devfs_ctx, xptr_t devfs_dev_inode_xp, xptr_t devfs_external_inode_xp ); /***************************************************************************************** * This function releases memory dynamically allocated for the DEVFS context. ***************************************************************************************** * @ devfs_ctx : local pointer on DEVFS context. ****************************************************************************************/ void devfs_ctx_destroy( devfs_ctx_t * devfs_ctx ); /***************************************************************************************** * This function start to create the DEVFS subtree. * This function should be called once in the cluster containing the VFS parent inode. * More precisely, it creates in cluster IO the "dev" and "external" DEVFS directories. * For each one, it creates the inode and link the associated dentry to parent inode. * The DEVFS root inode is linked to the VFS parent inode identified by . ***************************************************************************************** * @ parent_inode_xp : extended pointer on the parent VFS inode. * @ devfs_dev_inode_xp : [out] extended pointer on created inode. * @ devfs_external_inode_xp : [out] extended pointer on created inode. ****************************************************************************************/ void devfs_global_init( xptr_t parent_inode_xp, xptr_t * devfs_dev_inode_xp, xptr_t * devfs_external_inode_xp ); /***************************************************************************************** * This function completes the initialisation of the DEVFS subtree. * It should be called once in each cluster. * 1. In each cluster (i), it creates the "internal" directory, * linked to the DEVFS "dev" parent directory. * 2. In each cluster (i), it creates - for each external chdev in cluster (i) - * a pseudo-file, linked to the DEVFS "external" parent directory. * 3. In each cluster (i), it creates - for each internal chdev in cluster (i) - * a pseudo-file, linked to the DEVFS "internal" parent directory. ***************************************************************************************** * @ devfs_dev_inode_xp : extended pointer on DEVFS root inode. * @ devfs_external_inode_xp : extended pointer on DEVFS external inode. * @ devfs_internal_inode_xp : [out] extended pointer on created inode. ****************************************************************************************/ void devfs_local_init( xptr_t devfs_dev_inode_xp, xptr_t devfs_external_inode_xp, xptr_t * devfs_internal_inode_xp ); /****************************************************************************************** * This function moves bytes between a device, and a - possibly distributed - * user space . It uses the and arguments, to call the * relevant device access function. * It is called by the sys_read() and sys_write() functions. * The argument cannot be larger than the CONFIG_TXT_KBUF_SIZE configuration * parameter, as this function makes a copy between the user space buffer, and a local * kernel buffer allocated in the kernel stack. ****************************************************************************************** * @ to_buffer : device -> buffer if true / buffer -> device if false. * @ file_xp : extended pointer on the remote file descriptor. * @ u_buf : user space buffer (virtual address). * @ size : requested number of bytes from offset. * @ returns number of bytes actually moved if success / -1 if error. *****************************************************************************************/ int devfs_user_move( bool_t to_buffer, xptr_t file_xp, void * u_buf, uint32_t size ); #endif /* _DEVFS_H_ */