diff options
author | Ralf Baechle <ralf@linux-mips.org> | 1997-12-16 06:06:25 +0000 |
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committer | Ralf Baechle <ralf@linux-mips.org> | 1997-12-16 06:06:25 +0000 |
commit | aa944aa3453e47706685bc562711a9e87375941e (patch) | |
tree | 8fb37a65f205a90412917ca2b91c429263ef1790 /Documentation | |
parent | 967c65a99059fd459b956c1588ce0ba227912c4e (diff) |
Merge with Linux 2.1.72, part 2.
The new signal code with exception of the code for the rt signals.
The definitions in <asm/siginfo.h> and <asm/ucontext.h> are currently
just stolen from the Alpha and will need to be overhauled.
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/cdrom/Makefile | 21 | ||||
-rw-r--r-- | Documentation/filesystems/coda.txt | 1427 | ||||
-rw-r--r-- | Documentation/specialix.txt | 334 |
3 files changed, 1782 insertions, 0 deletions
diff --git a/Documentation/cdrom/Makefile b/Documentation/cdrom/Makefile new file mode 100644 index 000000000..a19e32192 --- /dev/null +++ b/Documentation/cdrom/Makefile @@ -0,0 +1,21 @@ +LATEXFILE = cdrom-standard + +all: + make clean + latex $(LATEXFILE) + latex $(LATEXFILE) + @if [ -x `which gv` ]; then \ + `dvips -q -t letter -o $(LATEXFILE).ps $(LATEXFILE).dvi` ;\ + `gv -antialias -media letter -nocenter $(LATEXFILE).ps` ;\ + else \ + `xdvi $(LATEXFILE).dvi &` ;\ + fi + make sortofclean + +clean: + rm -f $(LATEXFILE).ps $(LATEXFILE).dvi $(LATEXFILE).aux $(LATEXFILE).log + +sortofclean: + rm -f $(LATEXFILE).aux $(LATEXFILE).log + + diff --git a/Documentation/filesystems/coda.txt b/Documentation/filesystems/coda.txt new file mode 100644 index 000000000..829fd2d20 --- /dev/null +++ b/Documentation/filesystems/coda.txt @@ -0,0 +1,1427 @@ + The Venus kernel interface + Peter J. Braam + v1.0, Nov 9, 1997 + + This document describes the communication between Venus and kernel + level file system code needed for the operation of the Coda filesys- + tem. This version document is meant to describe the current interface + (version 1.0) as well as improvements we envisage. + ______________________________________________________________________ + + Table of Contents: + + 1. Introduction + + 2. Servicing Coda filesystem calls + + 3. The message layer + + 3.1. Implementation details + + 4. The interface at the call level + + 4.1. Data structures shared by the kernel and Venus + + 4.2. The pioctl interface + + 4.3. root + + 4.4. lookup + + 4.5. getattr + + 4.6. setattr + + 4.7. access + + 4.8. create + + 4.9. mkdir + + 4.10. link + + 4.11. synlink + + 4.12. remove + + 4.13. rmdir + + 4.14. readlink + + 4.15. open + + 4.16. close + + 4.17. ioctl + + 4.18. rename + + 4.19. readdir + + 4.20. vget + + 4.21. fsync + + 4.22. inactive + + 4.23. rdwr + + 4.24. odymount + + 4.25. ody_lookup + + 4.26. ody_expand + + 4.27. prefetch + + 4.28. signal + + 5. The minicache and downcalls + + 5.1. INVALIDATE + + 5.2. FLUSH + + 5.3. PURGEUSER + + 5.4. ZAPFILE + + 5.5. ZAPDIR + + 5.6. ZAPVNODE + + 5.7. PURGEFID + + 5.8. REPLACE + + 6. Initialization and cleanup + + 6.1. Requirements + ______________________________________________________________________ + 0wpage + + 11.. IInnttrroodduuccttiioonn + + A key component in the Coda Distributed File System is the cache + manager, _V_e_n_u_s. + + When processes on a Coda enabled system access files in the Coda + filesystem, requests are directed at the filesystem layer in the + operating system. The operating system will communicate with Venus to + service the request for the process. Venus manages a persistent + client cache and makes remote procedure calls to Coda file servers and + related servers (such as authentication servers) to service these + requests it receives from the operating system. When Venus has + serviced a request it replies to the operating system with appropiate + return codes, and other data related to the request. Optionally the + kernel support for Coda may maintain a minicache of recently processed + requests to limit the number of interactions with Venus. Venus + possesses the facility to inform the kernel when elements from its + minicache are no longer valid. + + This document describes precisely this communication between the + kernel and Venus. The definitions of so called upcalls and downcalls + will be given with the format of the data they handle. We shall also + describe the semantic invariants resulting from the calls. + + Historically Coda was implemented in a BSD file system in Mach 2.6. + The interface between the kernel and Venus is very similar to the BSD + VFS interface. Similar functionality is provided, and the format of + the parameters and returned data is very similar to the BSD VFS. This + leads to an almost natural environment for implementing a kernel level + filesystem driver for Coda in a BSD system. However, other operating + systems such as Linux and Windows 95 and NT have virtual filesystem + with different interfaces. + + To implement Coda on these systems some reverse engineering of the + Venus/Kernel protocol is necessary. Also it came to light that other + systems could profit significantly from certain small optimizations + and modifications to the protocol. To facilitate this work as well as + to make future ports easier, communication between Venus and the + kernel should be documented in great detail. This is the aim of this + document. + + 0wpage + + 22.. SSeerrvviicciinngg CCooddaa ffiilleessyysstteemm ccaallllss + + The service of a request for a Coda file system service originates in + a process PP which accessing a Coda file. It makes a system call which + traps to the OS kernel. Examples of such calls trapping to the kernel + are _r_e_a_d_, _w_r_i_t_e_, _o_p_e_n_, _c_l_o_s_e_, _c_r_e_a_t_e_, _m_k_d_i_r_, _r_m_d_i_r_, _c_h_m_o_d in a Unix + context. Similar calls exist in the Win32 environment, and are named + _C_r_e_a_t_e_F_i_l_e_, . + + Generally the operating system handles the request in a virtual + filesystem (VFS) layer, which is named I/O Manager in NT and IFS + manager in Windows 95. The VFS is responsible for partial processing + of the request and for locating the specific filesystem(s) which will + service parts of the request. Usually the information in the path + assists in locating the correct FS drivers. Sometimes after extensive + pre-processing, the VFS starts invoking exported routines in the FS + driver. This is the point where the FS specific processing of the + request starts, and here the Coda specific kernel code comes into + play. + + The FS layer for Coda must expose and implement several interfaces. + First and foremost the VFS must be able to make all necessary calls to + the Coda FS layer, so the Coda FS driver must expose the VFS interface + as applicable in the operating system. These differ very significantly + among operating systems, but share features such as facilities to + read/write and create and remove object. The Coda FS layer services + such VFS requests in by invoking on or more well defined services + offered by the cache manager Venus. When the replies from Venus have + come back to the FS driver, servicing of the VFS call continues and + finishes with a reply to the kernels VFS. Finally the VFS layer + returns to the process. + + As a result of this design a basic interface exposed by the FS driver + must allow Venus to handle manage message traffic. In particular + Venus must be able to retrieve and place messages and to be notified + of the arrival of a new message. The notification must be through a + mechanism which does not block Venus since Venus must attend to other + tasks even when no messages are waiting or being processed. + + Interfaces of Coda FS Driver + + Furthermore the FS layer provides for a special path of communication + between a user process and Venus, called the pioctl interface. The + pioctl interface is used for Coda specific services, such as + requesting detailed information about the persistent cache managed by + Venus. Here the involvement of the kernel is minimal. It identifies + the calling process and passes the information on to Venus. When + Venus replies the response is passed back to the caller in unmodified + form. + + Finally Venus allows the kernel FS driver to cache the results from + certain services. This is done to avoid excessive context switches + and results in an efficient system. However, Venus may acquire + information, for example from the network which implies that cached + information must be flushed or replaced. Venus then makes a downcall + to the Coda FS layer to request flushes or updates in the cache. The + kernel FS driver handles such requests synchronously. + + Among these interfaces the VFS interface and the facility to place, + receive and be notified of messages are platform specific. We will + not go into the calls exported to the VFS layer but we will state the + requirements of the message exchange mechanism. + + 0wpage + + 33.. TThhee mmeessssaaggee llaayyeerr + + At the lowest level the communication between Venus and the FS driver + proceeds through messages. The synchronization of between processes + requesting Coda file service and Venus relies on blocking and waking + up processes. The Coda FS driver processes VFS- and pioctl-requests + on behalf of a process P, creates messages for Venus, awaits replies + and finally returns to the caller. The implementation of the exchange + of messages is platform specific, but the semantics have (so far) + appeared to be generally applicable. Data buffers are created by the + FS Driver in kernel memory on behalf of P and copied to user memory in + Venus. + + The FS Driver while servicing P makes upcall's to Venus. Such an + upcall is dispatched to Venus by creating a message structure. The + structure contains the identification of P, the message sequence + number, the size of the request and a pointer to the data in kernel + memory for the request. Since the data buffer is re-used to hold the + reply from Venus, there is a field for the size of the reply. A flags + field is used in the message to precisely record the status of the + message. Additional platform dependent structures involve pointers to + determine the position of the message on queues and pointers to + synchronization objects. In the upcall routine the message structure + is filled in, flags are set to 0, and it is placed on the _p_e_n_d_i_n_g + queue. The routine calling upcall is responsible for allocating the + data buffer; it's structure will be described in the next section. + + A facility must exist to notify Venus that the message has been + created, and implemented using available synchronization objects in + the OS. This notification is done in the upcall context of the process + P. When the message is on the pending queue, process P cannot proceed + in upcall. The (kernel mode) processing of P in the filesystem + request routine must be suspended until Venus has replied. Therefore + the calling thread in P is blocked in upcall. A pointer in the + message structure will locate the synchronization object on which P is + sleeping. + + Venus detects the notification that a message has arrived, and the FS + driver allow Venus to retrieve the message with a getmsg_from_kernel + call. This action finishes in the kernel by putting the message on the + queue of processing messages and setting flags to READ. Venus is + passed the contents of the data buffer. The getmsg_from_kernel call + now returns and Venus processes the request. + + At some later point the FS driver receives a message from Venus, + namely when Venus calls sendmsg_to_kernel. At this moment the Coda FS + driver looks at the contents of the message and decides if: + + +o the message is a reply for a suspended thread P. If so it removes + the message from the processing queue and marks the message as + WRITTEN. Finally, the FS driver unblocks P (still in the kernel + mode context of Venus) and the sendmsg_to_kernel call returns to + Venus. The process P will be scheduled at some point and continues + processing its upcall with the data buffer replaced with the reply + from Venus. + + +o The message is a _d_o_w_n_c_a_l_l. A downcall is a request from Venus to + the FS Driver. The FS driver processes the request immediately + (usually a cach eviction or replacement) and when finishes + sendmsg_to_kernel returns. + + Now P awakes and continues processing upcall. There are some + subtleties to take account off. First P will determine if it was woken + up in upcall by a signal from some other source (for example an + attempt to terminate P) or as is normally the case by Venus in its + sendmsg_to_kernel call. In the normal case, the upcall routine will + deallocate message structure and return. The FS routine can proceed + with its processing. + + Sleeping and IPC arrangements + + In case P is woken up by a signal and not by Venus, it will first look + at the flags field. If the message is not yet READ, the process P can + handle it's signal without notifying Venus. If Venus has READ, and + the request should not be processed, P can send Venus a signal message + to indicate that it should disregard the previous message. Such + signals are put in the queue at the head, and read first by Venus. If + the message is already marked as WRITTEN it is too late to stop the + processing. The VFS routine will now continue. (-- If a VFS request + involves more than one upcall, this can lead to complicated state, an + extra field "handle_signals" could be added in the message structure + to indicate points of no return have been passed.--) + + 33..11.. IImmpplleemmeennttaattiioonn ddeettaaiillss + + The Unix implementation of this mechanism has been through the + implemenation of a character device associated with Coda. Venus + retrieves messages by doing a read on the device, replies are sent + with a write and notification is through the select system call on the + file descriptor for the device. The process P is kept waiting on an + interruptible wait queue object. + + In Windows NT and the DPMI Windows 95 implementation a DeviceIoControl + call is used. The DeviceIoControl call is designed to copy buffers + from user memory to kernel memory with OPCODES. The sendmsg_to_kernel + is issued as a synchronous call, while the getmsg_from_kernel call is + asynchrounous. Windows EventObjects are used for notification of + message arrival. The process P is kept waiting on a KernelEvent + object in NT and a semaphore in Windows 95. + + 0wpage + + 44.. TThhee iinntteerrffaaccee aatt tthhee ccaallll lleevveell + + This section describes the upcalls a Coda FS driver can make to Venus. + Each of these upcalls make use of two structures: inputArgs and + outputArgs. In pseudo BNF form the structures take the following + form: + + struct inputArgs { + u_long opcode; + u_long unique; /* Keep multiple outstanding msgs distinct */ + u_short pid; /* Common to all */ + u_short pgid; /* Common to all */ + struct CodaCred cred; /* Common to all */ + + <union "in" of call dependent parts of inputArgs> + }; + + struct outputArgs { + u_long opcode; + u_long unique; /* Keep multiple outstanding msgs distinct */ + u_long result; + + <union "out" of call dependent parts of inputArgs> + }; + + Before going on let us elucidate the role of the various fields. The + inputArgs start with the opcode which defines the type of service + requested from Venus. There are approximately 30 upcalls at present + which we will discuss. The unique field labels the inputArg with + unique number which will identify the message uniquely. A process and + process group id are passed. Finally the credentials of the caller + are included. + + Before delving into the specific calls we need to discuss a variety of + data structures shared by the kernel and Venus. + + 44..11.. DDaattaa ssttrruuccttuurreess sshhaarreedd bbyy tthhee kkeerrnneell aanndd VVeennuuss + + The CodaCred structure defines a variety of user and group id's as + they are set for the calling process. The vuid_t and guid_t are 32 bit + unsigned integers. It also defines group member ship in an array. On + Unix the CodaCred has proven sufficient to implement good security + semantics for Coda but the structure may have to undergo modification + for the Windows environment when these mature. + + struct CodaCred { + vuid_t cr_uid, cr_euid, cr_suid, cr_fsuid; /* Real, efftve, set, fs uid*/ + vgid_t cr_gid, cr_egid, cr_sgid, cr_fsgid; /* same for groups */ + vgid_t cr_groups[NGROUPS]; /* Group membership for caller */ + }; + + NNOOTTEE It is questionable if we need CodaCreds in Venus. Finally Venus + doesn't know about groups, although it does create files with the + default uid/gid. Perhaps the list of group membership is superfluous. + + The next item is the fundamental identifier used to identify Coda + files, the ViceFid. A fid of a file uniquely defines a file or + directory in the Coda filesystem within a _c_e_l_l. (-- A _c_e_l_l is a + group of Coda servers acting under the aegis of a single system + control machine or SCM. See the Coda Administration manual for a + detailed description of the role of the SCM.--) + + typedef struct ViceFid { + VolumeId Volume; + VnodeId Vnode; + Unique_t Unique; + } ViceFid; + + Each of the constituent fields: VolumeId, VnodeId and Unique_t are + unsigned 32 bit integers. We envisage that a further field will need + to be prefixed to identify the Coda cell; this will probably take the + form of a Ipv6 size IP address naming the Coda cell through DNS. + + The next important structure shared between Venus and the kernel are + the attributes of the file. The following structure is used to + exchange information. It has room for future extensions such as + support for device files (currently not present in Coda). + + struct coda_vattr { + enum coda_vtype va_type; /* vnode type (for create) */ + u_short va_mode; /* files access mode and type */ + short va_nlink; /* number of references to file */ + vuid_t va_uid; /* owner user id */ + vgid_t va_gid; /* owner group id */ + long va_fsid; /* file system id (dev for now) */ + long va_fileid; /* file id */ + u_quad_t va_size; /* file size in bytes */ + long va_blocksize; /* blocksize preferred for i/o */ + struct timespec va_atime; /* time of last access */ + struct timespec va_mtime; /* time of last modification */ + struct timespec va_ctime; /* time file changed */ + u_long va_gen; /* generation number of file */ + u_long va_flags; /* flags defined for file */ + dev_t va_rdev; /* device special file represents */ + u_quad_t va_bytes; /* bytes of disk space held by file */ + u_quad_t va_filerev; /* file modification number */ + u_int va_vaflags; /* operations flags, see below */ + long va_spare; /* remain quad aligned */ + }; + + 44..22.. TThhee ppiiooccttll iinntteerrffaaccee + + Coda specific requests can be made by application through a pioctl + interface. The pioctl is implemented as an ordinary ioctl on a + ficticious file /coda/.CONTROL. The piocl call opens this file, gets + a file handle and makes the ioctl call. Finally it closes the file. + + The kernel involvement in this is limited to providing the facility to + open and close and pass the ioctl message _a_n_d to verify that a path in + the pioctl data buffers is a file in a Coda filesystem. + + The kernel is handed a data packet of the form: + + struct { + const char *path; + struct ViceIoctl vidata; + int follow; + } data; + + where + + struct ViceIoctl { + caddr_t in, out; /* Data to be transferred in, or out */ + short in_size; /* Size of input buffer <= 2K */ + short out_size; /* Maximum size of output buffer, <= 2K */ + }; + + The path must be a Coda file, otherwise the ioctl upcall will not be + made. + + NNOOTTEE The data structures and code are a mess. We need to clean this + up. + + We now proceed to document the individual calls: + + 0wpage + + 44..33.. rroooott + + AArrgguummeennttss + + iinn empty + + oouutt + + struct cfs_root_out { + ViceFid VFid; + } cfs_root; + + DDeessccrriippttiioonn This call is made to Venus during the initialization of + the Coda filesystem. If the result is zero, the cfs_root structure + contains the ViceFid of the root of the Coda filesystem. If a non-zero + result is generated, its value is a platform dependent error code + indicating the difficulty Venus encountered in locating the root of + the Coda filesystem. + + 0wpage + + 44..44.. llooookkuupp + + SSuummmmaarryy Find the ViceFid and type of an object in a directory if it + exists. + + AArrgguummeennttss + + iinn + + struct cfs_lookup_in { + ViceFid VFid; + char *name; /* Place holder for data. */ + } cfs_lookup; + + oouutt + + struct cfs_lookup_out { + ViceFid VFid; + int vtype; + } cfs_lookup; + + DDeessccrriippttiioonn This call is made to determine the ViceFid and filetype of + a directory entry. The directory entry requested carries name name + and Venus will search the directory identified by cfs_lookup_in.VFid. + The result may indicate that the name does not exist, or that + difficulty was encountered in finding it (e.g. due to disconnection). + If the result is zero, the field cfs_lookup_out.VFid contains the + targets ViceFid and cfs_lookup_out.vtype the coda_vtype giving the + type of object the name designates. + + The name of the object is an 8 bit character string of maximum length + CFS_MAXNAMLEN, currently set to 256 (including a 0 terminator.) + + It is extremely important to realize that Venus bitwise or's the field + cfs_lookup.vtype with CFS_NOCACHE to indicate that the object should + not be put in the kernel name cache. + + NNOOTTEE The type of the vtype is currently wrong. It should be + coda_vtype. Linux does not take note of CFS_NOCACHE. It should. + + 0wpage + + 44..55.. ggeettaattttrr + + SSuummmmaarryy Get the attributes of a file. + + AArrgguummeennttss + + iinn + + struct cfs_getattr_in { + ViceFid VFid; + struct coda_vattr attr; /* XXXXX */ + } cfs_getattr; + + oouutt + + struct cfs_getattr_out { + struct coda_vattr attr; + } cfs_getattr; + + DDeessccrriippttiioonn This call returns the attributes of the file identified by + fid. + + EErrrroorrss Errors can occur if the object with fid does not exist, are + unaccessible or if the caller does not have permission to fetch + attributes. + + NNoottee Many kernel FS drivers (Linux, NT and Windows 95 need to acquire + the attributes as well as the Fid for the instantiation of an internal + "inode" or "FileHandle". A significant improvement in performance on + such systems could be made by combining the _l_o_o_k_u_p and _g_e_t_a_t_t_r calls + both at the Venus/kernel interaction level and at the RPC level. + + The vattr structure included in the input arguments is superfluous and + should be removed. + + 0wpage + + 44..66.. sseettaattttrr + + SSuummmmaarryy Set the attributes of a file. + + AArrgguummeennttss + + iinn + + struct cfs_setattr_in { + ViceFid VFid; + struct coda_vattr attr; + } cfs_setattr; + + oouutt + empty + + DDeessccrriippttiioonn The structure attr is filled with attributes to be changed + in BSD style. Attributes not to be changed are set to -1, apart from + vtype which is set to VNON. Other are set to the value to be assigned. + The only attributes which the FS driver may request to change are the + mode, ownner, groupid, atime, mtime and ctime. The return value + indicates success or failure. + + EErrrroorrss A variety of errors can occur. The object may not exist, may + be inaccessible, or permission may not be granted by Venus. + + 0wpage + + 44..77.. aacccceessss + + SSuummmmaarryy + + AArrgguummeennttss + + iinn + + struct cfs_access_in { + ViceFid VFid; + int flags; + } cfs_access; + + oouutt + empty + + DDeessccrriippttiioonn Verify if access to the object identified by VFid for + operetions described by flags is permitted. The result indicates if + access will be granted. It is important to remember that Coda uses + ACL's to enforce protection and that ultimately the servers, not the + clients enforce the security of the system. The result of this call + will depend on wether a _t_o_k_e_n is held by the user. + + EErrrroorrss The object may not exist, or the ACL describing the protection + may not be accessible. + + 0wpage + + 44..88.. ccrreeaattee + + SSuummmmaarryy Invoked to create a file + + AArrgguummeennttss + + iinn + + struct cfs_create_in { + ViceFid VFid; + struct coda_vattr attr; + int excl; + int mode; + char *name; /* Place holder for data. */ + } cfs_create; + + oouutt + + struct cfs_create_out { + ViceFid VFid; + struct coda_vattr attr; + } cfs_create; + + DDeessccrriippttiioonn This upcall is invoked to request creation of a file. + The file will be created in the directory identified by VFid, its name + will be name, and the mode will be mode. If excl is set an error will + be returned if the file already exists. If the size field in attr is + set to zero the file will be truncated. The uid and gid of the file + are set by converting the CodaCred to a uid using a macro CRTOUID + (this macro is platform dependent). Upon success the VFid and + attributes of the file are returned. The Coda FS Driver will normally + instantiate a vnode, inode or filehandle at kernel level for the new + object. + + EErrrroorrss A variety of errors can occur. Permissions may be insufficient. + If the object exists and is not a file the error EISDIR is returned + under Unix. + + NNOOTTEE The packing of parameters is very inefficient and appears to + indicate confusion between the system call creat and the VFS operation + create. The VFS operation create is only called to create new objects. + This create call differs from the Unix one in that it is not invoked + to return a file descriptor. The trunctate and exclusive options, + together with the mode, could simply be part of the mode as it is + under Unix. There should be no flags argument; this is used in open + (2) to return a filedescriptor for READ or WRITE mode. + + The attributes of the directory should be returned too, since the size + and mtime changed. + + 0wpage + + 44..99.. mmkkddiirr + + SSuummmmaarryy Create a new directory. + + AArrgguummeennttss + + iinn + + struct cfs_mkdir_in { + ViceFid VFid; + struct coda_vattr attr; + char *name; /* Place holder for data. */ + } cfs_mkdir; + + oouutt + + struct cfs_mkdir_out { + ViceFid VFid; + struct coda_vattr attr; + } cfs_mkdir; + + DDeessccrriippttiioonn This call is similar to create but creates a directory. + Only the mode field in the input parameters is used for creation. + Upon successful creation, the attr returned contains the attributes of + the new directory. + + EErrrroorrss As for create. + + NNOOTTEE The input parameter should be changed to mode instead of + attributes. + + The attributes of the parent should be returned since the size and + mtime changes. + + 0wpage + + 44..1100.. lliinnkk + + SSuummmmaarryy Create a link to an existing file. + + AArrgguummeennttss + + iinn + + struct cfs_link_in { + ViceFid sourceFid; /* cnode to link *to* */ + ViceFid destFid; /* Directory in which to place link */ + char *tname; /* Place holder for data. */ + } cfs_link; + + oouutt + empty + + DDeessccrriippttiioonn This call creates a link to the sourceFid in the directory + identified by destFid with name tname. The source must reside in the + targets parent, i.e. the source must be have parent destFid, i.e. Coda + does not support cross directory hard links. Only the return value is + relevant. It indicates success or the type of failure. + + EErrrroorrss The usual errors can occur.0wpage + + 44..1111.. ssyynnlliinnkk + + SSuummmmaarryy create a symbolic link + + AArrgguummeennttss + + iinn + + struct cfs_symlink_in { + ViceFid VFid; /* Directory to put symlink in */ + char *srcname; + struct coda_vattr attr; + char *tname; + } cfs_symlink; + + oouutt + none + + DDeessccrriippttiioonn Create a symbolic link. The link is to be placed in the + directory identified by VFid and named tname. It should point to the + pathname srcname. The attributes of the newly creaeted object are to + be set to attr. + + EErrrroorrss + + NNOOTTEE The attributes of the target directory should be returned since + its size changed. + + 0wpage + + 44..1122.. rreemmoovvee + + SSuummmmaarryy Remove a file + + AArrgguummeennttss + + iinn + + struct cfs_remove_in { + ViceFid VFid; + char *name; /* Place holder for data. */ + } cfs_remove; + + oouutt + none + + DDeessccrriippttiioonn Remove file named cfs_remove_in.name in directory + identified by VFid. + + EErrrroorrss + + NNOOTTEE The attributes of the directory should be returned since its + mtime and size may change. + + 0wpage + + 44..1133.. rrmmddiirr + + SSuummmmaarryy Remove a directory + + AArrgguummeennttss + + iinn + + struct cfs_rmdir_in { + ViceFid VFid; + char *name; /* Place holder for data. */ + } cfs_rmdir; + + oouutt + none + + DDeessccrriippttiioonn Remove the directory with name name from the directory + identified by VFid. + + EErrrroorrss + + NNOOTTEE The attributes of the parent directory should be returned since + its mtime and size may change. + + 0wpage + + 44..1144.. rreeaaddlliinnkk + + SSuummmmaarryy Read the value of a symbolic link. + + AArrgguummeennttss + + iinn + + struct cfs_readlink_in { + ViceFid VFid; + } cfs_readlink; + + oouutt + + struct cfs_readlink_out { + int count; + caddr_t data; /* Place holder for data. */ + } cfs_readlink; + + DDeessccrriippttiioonn This routine reads the contents of symbolic link + identified by VFid into the buffer data. The buffer data must be able + to hold any name up to CFS_MAXNAMLEN (PATH or NAM??). + + EErrrroorrss No unusual errors. + + 0wpage + + 44..1155.. ooppeenn + + SSuummmmaarryy Open a file. + + AArrgguummeennttss + + iinn + + struct cfs_open_in { + ViceFid VFid; + int flags; + } cfs_open; + + oouutt + + struct cfs_open_out { + dev_t dev; + ino_t inode; + } cfs_open; + + DDeessccrriippttiioonn This request asks Venus to place the file identified by + VFid in its cache and to note that the calling process wishes to open + it with flags as in open(2). The return value to the kernel differs + for Unix and Windows systems. For Unix systems the Coda FS Driver is + informed of the device and inode number of the container file in the + fields dev and inode. For Windows the path of the container file is + returned to the kernel. + + EErrrroorrss + + NNOOTTEE Currently the cfs_open_out structure is not properly adapted to + deal with the windows case. It might be best to implement two + upcalls, one to open aiming at a container file name, the other at a + container file inode. + + 0wpage + + 44..1166.. cclloossee + + SSuummmmaarryy Close a file, update it on the servers. + + AArrgguummeennttss + + iinn + + struct cfs_close_in { + ViceFid VFid; + int flags; + } cfs_close; + + oouutt + none + + DDeessccrriippttiioonn Close the file identified by VFid. + + EErrrroorrss + + NNOOTTEE The flags argument is bogus and not used. However, Venus' code + has room to deal with an execp input field, probably this field should + be used to inform Venus that the file was closed but is still memory + mapped for execution. There are comments about fetching versus not + fetching the data in Venus vproc_vfscalls. This seems silly. If a + file is being closed, the data in the container file is to be the new + data. Here again the execp flag might be in play to create confusion: + presently Venus might think a file can be flushed from the cache when + it is still memory mapped. This needs to be understood. + + 0wpage + + 44..1177.. iiooccttll + + SSuummmmaarryy Do an ioctl on a file. This includes the piocl interface. + + AArrgguummeennttss + + iinn + + struct cfs_ioctl_in { + ViceFid VFid; + int cmd; + int len; + int rwflag; + char *data; /* Place holder for data. */ + } cfs_ioctl; + + oouutt + + struct cfs_ioctl_out { + int len; + caddr_t data; /* Place holder for data. */ + } cfs_ioctl; + + DDeessccrriippttiioonn Do an ioctl operation on a file. The command, len and + data arguments are filled as usual. flags is not used by Venus. + + EErrrroorrss + + NNOOTTEE Another bogus parameter. flags is not used. What is the + business about PREFETCHING in the Venus' code? + + 0wpage + + 44..1188.. rreennaammee + + SSuummmmaarryy Rename a fid. + + AArrgguummeennttss + + iinn + + struct cfs_rename_in { + ViceFid sourceFid; + char *srcname; + ViceFid destFid; + char *destname; + } cfs_rename; + + oouutt + none + + DDeessccrriippttiioonn Rename the object with name srcname in directory + sourceFid to destname in destFid. It is important that the names + srcname and destname are 0 terminated strings. Strings in Unix + kernels are not always null terminated. + + EErrrroorrss + + 0wpage + + 44..1199.. rreeaaddddiirr + + SSuummmmaarryy Read directory entries. + + AArrgguummeennttss + + iinn + + struct cfs_readdir_in { + ViceFid VFid; + int count; + int offset; + } cfs_readdir; + + oouutt + + struct cfs_readdir_out { + int size; + caddr_t data; /* Place holder for data. */ + } cfs_readdir; + + DDeessccrriippttiioonn Read directory entries from VFid starting at offset and + read at most count bytes. Returns the data into data and indicates + the size returned size. + + EErrrroorrss + + NNOOTTEE This call is not used. Readdir operations exploit container + files. We will re-evaluate this during the directory revamp which is + about to take place. + + 0wpage + + 44..2200.. vvggeett + + SSuummmmaarryy instructs Venus to do an FSDB->Get. + + AArrgguummeennttss + + iinn + + struct cfs_fsync_in { + ViceFid VFid; + } cfs_fsync; + + oouutt + + struct cfs_vget_out { + ViceFid VFid; + int vtype; + } cfs_vget; + + DDeessccrriippttiioonn This upcall asks Venus to do a get operation on an fsobj + labelled by VFid. + + EErrrroorrss + + NNOOTTEE This operation is not used. However, it is extremely useful + since it can be used to deal with read/write memory mapped files. + These can be "pinned" in the Venus cache using vget and release with + inactive. + + 0wpage + + 44..2211.. ffssyynncc + + SSuummmmaarryy Tell Venus to update the RVM attributes of a file. + + AArrgguummeennttss + + iinn + + struct cfs_fsync_in { + ViceFid VFid; + } cfs_fsync; + + oouutt + none + + DDeessccrriippttiioonn Ask Venus to update RVM attributes of object VFid. This + should be called as part of kernel level fsync type calls. The + result indicates if the synching was successful. + + EErrrroorrss + + NNOOTTEE Linux does not implement this call. It should. + + 0wpage + + 44..2222.. iinnaaccttiivvee + + SSuummmmaarryy Tell Venus a vnode is no longer in use. + + AArrgguummeennttss + + iinn + + struct cfs_inactive_in { + ViceFid VFid; + } cfs_inactive; + + oouutt + none + + DDeessccrriippttiioonn This operation returns EOPNOTSUPP. + + EErrrroorrss + + NNOOTTEE This should perhaps be removed. + + 0wpage + + 44..2233.. rrddwwrr + + SSuummmmaarryy Read or write from a file + + AArrgguummeennttss + + iinn + + struct cfs_rdwr_in { + ViceFid VFid; + int rwflag; + int count; + int offset; + int ioflag; + caddr_t data; /* Place holder for data. */ + } cfs_rdwr; + + oouutt + + struct cfs_rdwr_out { + int rwflag; + int count; + caddr_t data; /* Place holder for data. */ + } cfs_rdwr; + + DDeessccrriippttiioonn This upcall asks Venus to read or write from a file. + + EErrrroorrss + + NNOOTTEE It should be removed since it is against the Coda philosophy that + read/write operations never reach Venus. I have been told the + operation does not work. It is not currently used. + + 0wpage + + 44..2244.. ooddyymmoouunntt + + SSuummmmaarryy Allows mounting multiple Coda "filesystems" on one Unix mount + point. + + AArrgguummeennttss + + iinn + + struct ody_mount_in { + char *name; /* Place holder for data. */ + } ody_mount; + + oouutt + + struct ody_mount_out { + ViceFid VFid; + } ody_mount; + + DDeessccrriippttiioonn Asks Venus to return the rootfid of a Coda system named + name. The fid is returned in VFid. + + EErrrroorrss + + NNOOTTEE This call was used by David for dynamic sets. It should be + removed since it causes a jungle of pointers in the VFS mounting area. + It is not used by Coda proper. Call is not implemented by Venus. + + 0wpage + + 44..2255.. ooddyy__llooookkuupp + + SSuummmmaarryy Looks up something. + + AArrgguummeennttss + + iinn irrelevant + + oouutt + irrelevant + + DDeessccrriippttiioonn + + EErrrroorrss + + NNOOTTEE Gut it. Call is not implemented by Venus. + + 0wpage + + 44..2266.. ooddyy__eexxppaanndd + + SSuummmmaarryy expands something in a dynamic set. + + AArrgguummeennttss + + iinn irrelevant + + oouutt + irrelevant + + DDeessccrriippttiioonn + + EErrrroorrss + + NNOOTTEE Gut it. Call is not implemented by Venus. + + 0wpage + + 44..2277.. pprreeffeettcchh + + SSuummmmaarryy Prefetch a dynamic set. + + AArrgguummeennttss + + iinn Not documented. + + oouutt + Not documented. + + DDeessccrriippttiioonn Venus worker.cc has support for this call, although it is + noted that it doesn't work. Not surprising, since the kernel does not + have support for it. (ODY_PREFETCH is not a defined operation). + + EErrrroorrss + + NNOOTTEE Gut it. It isn't working and isn't used by Coda. + + 0wpage + + 44..2288.. ssiiggnnaall + + SSuummmmaarryy Send Venus a signal about an upcall. + + AArrgguummeennttss + + iinn none + + oouutt + not applicable. + + DDeessccrriippttiioonn This is an out-of-band upcall to Venus to inform Venus + that the calling process received a signal after Venus read the + message from the input queue. Venus is supposed to clean up the + operation. + + EErrrroorrss No reply is given. + + NNOOTTEE We need to better understand what Venus needs to clean up and if + it is doing this correctly. Also we need to handle multiple upcall + per system call situations correctly. It would be important to know + what state changes in Venus take place after an upcall for which the + kernel is responsible for notifying Venus to clean up (e.g. open + definitely is such a state change, but many others are maybe not). + + 0wpage + + 55.. TThhee mmiinniiccaacchhee aanndd ddoowwnnccaallllss + + The Coda FS Driver can cache results of lookup and access upcalls, to + limit the frequency of upcalls. Upcalls carry a price since a process + context switch needs to take place. The counterpart of caching the + information is that Venus will notify the FS Driver that cached + entries must be flushed or renamed. + + The kernel code generally has to maintain a structure which links the + internal file handles (called vnodes in BSD, inodes in Linux and + FileHandles in Windows) with the ViceFid's which Venus maintains. + Ther reason is that frequent translations back and forth are needed in + order to make upcalls and use the results of upcalls. Such linking + objects are called ccnnooddeess. + + The current minicache implementations have cache entries which record + the following: + + 1. the name of the file + + 2. the cnode of the directory containing the object + + 3. a list of CodaCred's for which the lookup is permitted. + + 4. the cnode of the object + + The lookup call in the Coda FS Driver may request the cnode of the + desired object from the cache, by passing it's name, directory and the + CodaCred's of the caller. The cache will return the cnode or indicate + and it cannot be found. The Coda FS Driver must be careful to + invalidate cache entries when it modifies or removes objects. + + When Venus obtains information that indicates that cache entries are + no longer valid, it will make a downcall to the kernel. Downcalls are + intercepted by the Coda FS Driver and lead to cache invalidations of + the kind described below. The Coda FS Driver does not return an error + unless the downcall data could not be read into kernel memory. + + 55..11.. IINNVVAALLIIDDAATTEE + + No information is available on this call. + + 55..22.. FFLLUUSSHH + + AArrgguummeennttss None + + SSuummmmaarryy Flush the name cache entirely. + + DDeessccrriippttiioonn Venus issues this call upon startup and when it dies. This + is to prevent stale cache information being held. Some operating + systems allow the kernel name cache to be switched off dynamically. + When this is done, this downcall is made. + + 55..33.. PPUURRGGEEUUSSEERR + + AArrgguummeennttss + + struct cfs_purgeuser_out {/* CFS_PURGEUSER is a venus->kernel call */ + struct CodaCred cred; + } cfs_purgeuser; + + DDeessccrriippttiioonn Remove all entries in the cache carrying the Cred. This + call is issued when tokes for a user expire or are flushed. + + 55..44.. ZZAAPPFFIILLEE + + AArrgguummeennttss + + struct cfs_zapfile_out { /* CFS_ZAPFILE is a venus->kernel call */ + ViceFid CodaFid; + } cfs_zapfile; + + DDeessccrriippttiioonn Remove all entries which have the (dir vnode, name) pair. + This is issued as a result of an invalidation of cached attributes of + a vnode. + + NNOOTTEE Call is not named correctly in NetBSD and Mach. The minicache + zapfile routine takes different arguments. Linux does not implement + the invalidation of attributes correctly. + + 55..55.. ZZAAPPDDIIRR + + AArrgguummeennttss + + struct cfs_zapdir_out { /* CFS_ZAPDIR is a venus->kernel call */ + ViceFid CodaFid; + } cfs_zapdir; + + DDeessccrriippttiioonn Remove all entries in the cache lying in a directory + CodaFid, and all children of this directory. This call is issed when + Venus receives a callback on the this directory. + + 55..66.. ZZAAPPVVNNOODDEE + + AArrgguummeennttss + + struct cfs_zapvnode_out { /* CFS_ZAPVNODE is a venus->kernel call */ + struct CodaCred cred; + ViceFid VFid; + } cfs_zapvnode; + + DDeessccrriippttiioonn Remove all entries in the cache carrying the cred and VFid + as in the arguments. This downcall is probably never issued. + + 55..77.. PPUURRGGEEFFIIDD + + SSuummmmaarryy + + AArrgguummeennttss + + struct cfs_purgefid_out { /* CFS_PURGEFID is a venus->kernel call */ + ViceFid CodaFid; + } cfs_purgefid; + + DDeessccrriippttiioonn Flush the attribute for the file. If it is a dir (odd + vnode), purge its children from the namecache remove the file from the + namecache. + + 55..88.. RREEPPLLAACCEE + + SSuummmmaarryy Replace the Fid's for a collection of names. + + AArrgguummeennttss + + struct cfs_replace_out { /* cfs_replace is a venus->kernel call */ + ViceFid NewFid; + ViceFid OldFid; + } cfs_replace; + + DDeessccrriippttiioonn This routine replaces a ViceFid in the name cache with + another. It is added to allow Venus during reintegration to replace + locally allocated temp fids while disconnected with global fids even + when the reference count on those fids are not zero. + + 0wpage + + 66.. IInniittiiaalliizzaattiioonn aanndd cclleeaannuupp + + This section gives brief hints as to desirable features for the Coda + FS Driver at startup and upon shutdown or Venus failures. Before + entering the discussion it is useful to repeat that the Coda FS Driver + maintains the following data: + + 1. message queues + + 2. cnodes + + 3. name cache entries + + The name cache entries are entirely private to the driver, so they + can easily be manipulated. The message queues will generally have + clear points of initialization and destruction. The cnodes are + much more delicate. User processes hold reference counts in Coda + filesystems and it can be difficult to clean up the cnodes. + + It can expect requests through: + + 1. the message subsystem + + 2. the VFS layer + + 3. pioctl interface + + Currently the _p_i_o_c_t_l passes through the VFS for Coda so we can + treat these similarly. + + 66..11.. RReeqquuiirreemmeennttss + + The following requirements should be accomodated: + + 1. The message queueus should have open and close routines. On Unix + the opening of the character devices are such routines. + + +o Before opening, no messages can be placed. + + +o Opening will remove any old messages still pending. + + +o Close will notify any sleeping processes that their upcall cannot + be completed. + + +o Close will free all memory allocated by the message queues. + + 2. At open the namecache shall be initialized to empty state. + + 3. Before the message queues are open, all VFS operations will fail. + Fortunately this can be achieved by making sure than mounting the + Coda filesystem cannot succeed before opening. + + 4. After closing of the queues, no VFS operations can succeed. Here + one needs to be careful, since a few operations (lookup, + read/write, readdir) can proceed without upcalls. These must be + explicitly blocked. + + 5. Upon closing the namecache shall be flushed and disabled. + + 6. All memory held by cnodes can be freed without relying on upcalls. + + 7. Unmounting the file system can be done without relying on upcalss. + + 8. Mounting the Coda filesystem should fail gracefully if Venus cannot + get the rootfid or the attributes of the rootfid. The latter is + best implemented by Venus fetching these objects before attempting + to mount. + + NNOOTTEE NetBSD in particular but also Linux have not implemented the + above requirements fully. For smooth operation this needs to be + corrected. + diff --git a/Documentation/specialix.txt b/Documentation/specialix.txt new file mode 100644 index 000000000..cb4eeb7cb --- /dev/null +++ b/Documentation/specialix.txt @@ -0,0 +1,334 @@ + + specialix.txt -- specialix IO8+ multiport serial driver readme. + + + + Copyright (C) 1997 Roger Wolff (R.E.Wolff@BitWizard.nl) + + Specialix pays for the development and support of this driver. + Please DO contact io8-linux@specialix.co.uk if you require + support. + + This driver was developed in the BitWizard linux device + driver service. If you require a linux device driver for your + product, please contact devices@BitWizard.nl for a quote. + + This code is firmly based on the riscom/8 serial driver, + written by Dmitry Gorodchanin. The specialix IO8+ card + programming information was obtained from the CL-CD1865 Data + Book, and Specialix document number 6200059: IO8+ Hardware + Functional Specification. + + This program 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; either version 2 of + the License, or (at your option) any later version. + + This program 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 this program; if not, write to the Free + Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, + USA. + + +Intro +===== + + +This file contains some random information, that I like to have online +instead of in a manual that can get lost. Ever misplace your Linux +kernel sources? And the manual of one of the boards in your computer? + + +Adresses and interrupts +======================= + +Addres dip switch settings: +The dip switch sets bits 2-9 of the IO address. + + 9 8 7 6 5 4 3 2 + +-----------------+ + 0 | X X X X X X X | + | | = IoBase = 0x100 + 1 | X | + +-----------------+ ------ RS232 connectors ----> + + | | | + edge connector + | | | + V V V + +Base address 0x100 caused a conflict in one of my computers once. I +haven't the foggiest why. My Specialix card is now at 0x180. My +other computer runs just fine with the Specialix card at 0x100.... +The card occupies 4 addresses, but actually only two are really used. + +The driver now still autoprobes at 0x100, 0x180, 0x250 and 0x260. If +that causes trouble for you, please report that. I'll remove +autoprobing then. + +The driver will tell the card what IRQ to use, so you don't have to +change any jumpers to change the IRQ. Just use a command line +argument (irq=xx) to the insmod program to set the interrupt. + +If your specialix cards are not at the default locations, you can use +the kernel command line argument "specialix=io0,irq0,io1,irq1...". +Here "io0" is the io address for the first card, and "irq0" is the +irq line that the first card should use. And so on. + +Examples. + +You use the driver as a module and have three cards at 0x100, 0x250 +and 0x180. And some way or another you want them detected in that +order. Moreover irq 12 is taken (e.g. by your PS/2 mouse). + + insmod specialix.o iobase=0x100,0x250,0x180 irq=9,11,15 + +The same three cards, but now in the kernel would require you to +add + + specialix=0x100,9,0x250,11,0x180,15 + +to the command line. This would become + + append="specialix=0x100,9,0x250,11,0x180,15" + +in your /etc/lilo.conf file if you use lilo. + + +Baud rates +========== + +The rev 1.2 and below boards use a CL-CD1864. These chips can only +do 64kbit. The rev 1.3 and newer boards use a CL-CD1865. These chips +are officially capable of 115k2. + +The Specialix card uses a 25MHz crystal (in times two mode, which in +fact is a divided by two mode). This is not enough to reach the rated +115k2 on all ports at the same time. With this clock rate you can only +do 37% of this rate. This means that at 115k2 on all ports you are +going to loose characters (The chip cannot handle that many incoming +bits at this clock rate.) (Yes, you read that correctly: there is a +limit to the number of -=bits=- per second that the chip can handle.) + +If you near the "limit" you will first start to see a graceful +degradation in that the chip cannot keep the transmitter busy at all +times. However with a central clock this slow, you can also get it to +miss incoming characters. + +The specialix card cannot reliably do 115k2. If you use it, you have +to do "extensive testing" (*) to verify if it actually works. + +When "mgetty" communicates with my modem at 115k2 it reports: +got: +++[0d]ATQ0V1H0[0d][0d][8a]O[cb][0d][8a] + ^^^^ ^^^^ ^^^^ + +The three characters that have the "^^^" under them have suffered a +bit error in the highest bit. In conclusion: I've tested it, and found +that it simply DOESN"T work for me. I also suspect that this is also +caused by the baud rate being just a little bit out of tune. + + +(*) Cirrus logic CD1864 databook, page 40. + + +Cables for the Specialix IO8+ +============================= + +The pinout of the connectors on the IO8+ is: + + pin short direction long name + name + Pin 1 DCD input Data Carrier Detect + Pin 2 RXD input Receive + Pin 3 DTR/RTS output Data Terminal Ready/Ready To Send + Pin 4 GND - Ground + Pin 5 TXD output Transmit + Pin 6 CTS input Clear To Send + + + -- 6 5 4 3 2 1 -- + | | + | | + | | + | | + +----- -----+ + |__________| + clip + + Front view of an RJ12 connector. Cable moves "into" the paper. + (the plug is ready to plug into your mouth this way...) + + + NULL cable. I don't know who is going to use these except for + testing purposes, but I tested the cards with this cable. (It + took quite a while to figure out, so I'm not going to delete + it. So there! :-) + + + This end goes This end needs + straight into the some twists in + RJ12 plug. the wiring. + IO8+ RJ12 IO8+ RJ12 + 1 DCD white - + - - 1 DCD + 2 RXD black 5 TXD + 3 DTR/RTS red 6 CTS + 4 GND green 4 GND + 5 TXD yellow 2 RXD + 6 CTS blue 3 DTR/RTS + + + Same NULL cable, but now sorted on the second column. + + 1 DCD white - + - - 1 DCD + 5 TXD yellow 2 RXD + 6 CTS blue 3 DTR/RTS + 4 GND green 4 GND + 2 RXD black 5 TXD + 3 DTR/RTS red 6 CTS + + + + This is a modem cable usable for hardware handshaking: + RJ12 DB25 DB9 + 1 DCD white 8 DCD 1 DCD + 2 RXD black 3 RXD 2 RXD + 3 DTR/RTS red 4 RTS 7 RTS + 4 GND green 7 GND 5 GND + 5 TXD yellow 2 TXD 3 TXD + 6 CTS blue 5 CTS 8 CTS + +---- 6 DSR 6 DSR + +---- 20 DTR 4 DTR + + This is a modem cable usable for software handshaking: + It allows you to reset the modem using the DTR ioctls. + I (REW) have never tested this, "but xxxxxxxxxxxxx + says that it works." If you test this, please + tell me and I'll fill in your name on the xxx's. + + RJ12 DB25 DB9 + 1 DCD white 8 DCD 1 DCD + 2 RXD black 3 RXD 2 RXD + 3 DTR/RTS red 20 DTR 4 DTR + 4 GND green 7 GND 5 GND + 5 TXD yellow 2 TXD 3 TXD + 6 CTS blue 5 CTS 8 CTS + +---- 6 DSR 6 DSR + +---- 4 RTS 7 RTS + + I bought a 6 wire flat cable. It was colored as indicated. + Check that yours is the same before you trust me on this. + + +Hardware handshaking issues. +============================ + +The driver can be compiled in two different ways. The default +("Specialix DTR/RTS pin is RTS" is off) the pin behaves as DTR when +hardware handshaking is off. It behaves as the RTS hardware +handshaking signal when hardware handshaking is selected. + +When you use this, you have to use the appropriate cable. The +cable will either be compatible with hardware handshaking or with +software handshaking. So switching on the fly is not really an +option. + +I actually prefer to use the "Specialix DTR/RTS pin is RTS" option. +This makes the DTR/RTS pin always an RTS pin, and ioctls to +change DTR are always ignored. I have a cable that is configured +for this. + + +Ports and devices +================= + +Port 0 is the one furthest from the ISA connector. + +Devices: + +You should make the devices as follows: + +bash +cd /dev +for i in 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 \ + 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 +do + echo -n "$i " + mknod /dev/ttyW$i c 75 $i + mknod /dev/cuw$i c 76 $i +done +echo "" + + +You cannot have more than 4 boards in one computer. The card only +supports 4 different interrupts. If you really want this, contact me +about this and I'll give you a few tips (requires soldering iron).... + + +------------------------------------------------------------------------ + + + Fixed bugs and restrictions: + - During intialization, interrupts are blindly turned on. + Having a shadow variable would cause an extra memory + access on every IO instruction. + - The interrupt (on the card) should be disabled when we + don't allocate the Linux end of the interrupt. This allows + a different driver/card to use it while all ports are not in + use..... (a la standard serial port) + == An extra _off variant of the sx_in and sx_out macros are + now available. They don't set the interrupt enable bit. + These are used during initialization. Normal operation uses + the old variant which enables the interrupt line. + - RTS/DTR issue needs to be implemented according to + specialix' spec. + I kind of like the "determinism" of the current + implementation. Compile time flag? + == Ok. Compile time flag! Default is how Specialix likes it. + == Now a config time flag! Gets saved in your config file. Neat! + - Can you set the IO address from the lilo command line? + If you need this, bug me about it, I'll make it. + == Hah! No bugging needed. Fixed! :-) + - Cirrus logic hasn't gotten back to me yet why the CD1865 can + and the CD1864 can't do 115k2. I suspect that this is + because the CD1864 is not rated for 33MHz operation. + Therefore the CD1864 versions of the card can't do 115k2 on + all ports just like the CD1865 versions. The driver does + not block 115k2 on CD1864 cards. + == I called the Cirrus Logic representative here in Holland. + The CD1864 databook is identical to the CD1865 databook, + except for an extra warning at the end. Similar Bit errors + have been observed in testing at 115k2 on both an 1865 and + a 1864 chip. I see no reason why I would prohibit 115k2 on + 1864 chips and not do it on 1865 chips. Actually there is + reason to prohibit it on BOTH chips. I print a warning. + If you use 115k2, you're on your own. + - A spiky CD may send spurious HUPs. Also in CLOCAL??? + -- A fix for this turned out to be counter productive. + Different fix? Current behaviour is acceptable? + -- Maybe the current implementation is correct. If anybody + gets bitten by this, please report, and it will get fixed. + + -- Testing revealed that when in CLOCAL, the problem doesn't + occur. As warned for in the CD1865 manual, the chip may + send modem intr's on a spike. We could filter those out, + but that would be a cludge anyway (You'd still risk getting + a spurious HUP when two spikes occur.)..... + + + + Bugs & restrictions: + - This is a difficult card to autoprobe. + You have to WRITE to the address register to even + read-probe a CD186x register. Disable autodetection? + -- Specialix: any suggestions? + - Arbitrary baud rates are not implemented yet. + If you need this, bug me about it. + + |