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Diffstat (limited to 'share')
-rw-r--r-- | share/man/man4/fdc.4 | 227 |
1 files changed, 131 insertions, 96 deletions
diff --git a/share/man/man4/fdc.4 b/share/man/man4/fdc.4 index 94b1cfd..fd2e5ad 100644 --- a/share/man/man4/fdc.4 +++ b/share/man/man4/fdc.4 @@ -32,7 +32,7 @@ .Os .Sh NAME .Nm fdc -.Nd PC architecture floppy disk controller driver +.Nd "PC architecture floppy disk controller driver" .Sh SYNOPSIS .Cd device fdc .Cd device fd @@ -52,21 +52,26 @@ In .Cd hint.fd.1.flags="0x0" .Sh DESCRIPTION .Ss Device Usage -This driver provides access to floppy disk drives. Floppy disks using +This driver provides access to floppy disk drives. +Floppy disks using either FM (single-density) or MFM (double or high-density) recording can be handled. .Pp -Floppy disk controllers can connect up to four drives each. The +Floppy disk controllers can connect up to four drives each. +The .Nm -driver can currently handle up to two drives per controller. Upon +driver can currently handle up to two drives per controller. +Upon driver initialization, an attempt is made to find out the type of the -floppy controller in use. The known controller types are either the +floppy controller in use. +The known controller types are either the original NE765 or i8272 chips, or alternatively .Em enhanced controllers that are compatible with the NE72065 or i82077 chips. These enhanced controllers (among other enhancements) implement a FIFO for floppy data transfers that will automatically be enabled once an -enhanced chip has been detected. This FIFO activation can be disabled +enhanced chip has been detected. +This FIFO activation can be disabled using the per-controller flags value of .Ar 0x1 . .Pp @@ -83,14 +88,18 @@ can also be accessed, which will be implemented as symbolic links to the main device node. .Pp Accessing the main device node will attempt to autodetect the density -of the available medium for multi-density devices. Thus it is +of the available medium for multi-density devices. +Thus it is possible to use either a 720 KB medium or a 1440 KB medium in a -high-density 3.5 inch standard floppy drive. Normally, this +high-density 3.5 inch standard floppy drive. +Normally, this autodetection will only happen once at the first call to .Xr open 2 -for the device after inserting the medium. This assumes the drive +for the device after inserting the medium. +This assumes the drive offers proper changeline support so media changes can be detected by -the driver. To indicate a drive that doesn't have changeline support, +the driver. +To indicate a drive that does not have the changeline support, this can be overridden using the per-drive device flags value of .Ar 0x10 (causing each call to @@ -105,21 +114,25 @@ where is the drive number, and .Ar MMMM is a number between one and four digits describing the device density. -Up to 15 additional subdevices per drive can be created that way. The +Up to 15 additional subdevices per drive can be created that way. +The administrator is free to decide on a policy how to assign these -numbers. The two common policies are to either implement subdevices +numbers. +The two common policies are to either implement subdevices numbered 1 through 15, or to use a number that describes the medium -density in kilobytes. Initially, each of those devices will be +density in kilobytes. +Initially, each of those devices will be configured to the maximal density that is possible for the drive type (like 1200 KB for 5.25 inch HD drives or 1440 KB for 3.5 inch HD -drives). The desired density to be used on that subdevice needs to be +drives). +The desired density to be used on that subdevice needs to be configured using .Xr fdcontrol 8 . .Pp Drive types are configured using the lower four bits of the per-drive -device flags. The following values can be specified: -.Pp -.Bl -tag -width NN -offset indent +device flags. +The following values can be specified: +.Bl -tag -width 2n -offset indent .It Ar 1 5.25 inch double-density device with 40 cylinders (360 KB native capacity) @@ -140,16 +153,20 @@ Same as type 5, available for compatibility with some BIOSes .El .Pp On IA32 architectures, the drive type can be specified as 0 for the -first two drives. In that case, the CMOS configuration memory will be +first two drives. +In that case, the CMOS configuration memory will be consulted to obtain the value for that drive. .Pp Normally, each configured drive will be probed at initialization -time, using a short seek sequence. This is intended to find out about -about drives that have been configured but are actually missing or -otherwise not responding. In some environments (like laptops with +time, using a short seek sequence. +This is intended to find out about +drives that have been configured but are actually missing or +otherwise not responding. +In some environments (like laptops with detachable drives), it might be desirable to bypass this drive probe, and pretend a drive to be there so the driver autoconfiguration will -work even if the drive is currently not present. For that purpose, a +work even if the drive is currently not present. +For that purpose, a per-drive device flags value of .Ar 0x20 needs to be specified. @@ -161,145 +178,163 @@ driver offers a number of configurable options using .Xr ioctl 2 . In order to access any of this functionality, programmers need to include the header file -.Pp -.In sys/fdcio.h -.Pp -into their programs. The call to +.Aq Pa sys/fdcio.h +into their programs. +The call to .Xr open 2 -can be performed in two possible ways. When opening the device +can be performed in two possible ways. +When opening the device without the -.Li O_NONBLOCK +.Dv O_NONBLOCK flag set, the device is opened in a normal way, which would cause the main device nodes to perform automatic media density selection, and which -will yield a file descriptor that is fully available for any IO operation +will yield a file descriptor that is fully available for any I/O operation or any of the following .Xr ioctl 2 commands. .Pp Whe opening the device with -.Li O_NONBLOCK +.Dv O_NONBLOCK set, automatic media density selection will be bypassed, and the device -remains in a half-opened state. No actual IO operations are possible, but +remains in a half-opened state. +No actual I/O operations are possible, but many of the .Xr ioctl 2 -commands described below can be performed. This mode is intended for +commands described below can be performed. +This mode is intended for access to the device without the requirement to have an accessible media present, like for status inquiries to the drive, or in order to format a medium. -.Li O_NONBLOCK -needs to be cleared before IO operations are possible on the descriptor, +.Dv O_NONBLOCK +needs to be cleared before I/O operations are possible on the descriptor, which requires a prior specification of the density using the -.Li FD_STYPE -command (see below). Operations that are not allowed on the half-opened +.Dv FD_STYPE +command (see below). +Operations that are not allowed on the half-opened descriptor will cause an error value of -.Ev EAGAIN . +.Er EAGAIN . .Pp The following .Xr ioctl 2 commands are currently available: -.Pp -.Bl -tag -width FD_READID -offset indent -.It Li FD_FORM -Used to format a floppy disk medium. Third argument is a pointer to a -.Li struct fd_formb +.Bl -tag -width ".Dv FD_READID" +.It Dv FD_FORM +Used to format a floppy disk medium. +Third argument is a pointer to a +.Vt "struct fd_formb" specifying which track to format, and which parameters to fill into the ID fields of the floppy disk medium. -.It Li FD_GTYPE +.It Dv FD_GTYPE Returns the current density definition record for the selected device. Third argument is a pointer to -.Li struct fd_type . -.It Li FD_STYPE -Adjusts the density definition of the selected device. Third argument +.Vt "struct fd_type" . +.It Dv FD_STYPE +Adjusts the density definition of the selected device. +Third argument is a pointer to -.Li struct fd_type . +.Vt "struct fd_type" . For the fixed-density subdevices (1 through 15 per drive), this -operation is restricted to a process with superuser privileges. For +operation is restricted to a process with superuser privileges. +For the auto-selecting subdevice 0, the operation is temporarily allowed to any process, but this setting will be lost again upon the next -autoselection. This can be used when formatting a new medium (which +autoselection. +This can be used when formatting a new medium (which will require to open the device using -.Li O_NONBLOCK , +.Dv O_NONBLOCK , and thus to later adjust the density using -.Li FD_STYPE ) . -.It Li FD_GOPTS -Obtain the current drive options. Third argument is a pointer to -.Li int , +.Dv FD_STYPE ) . +.It Dv FD_GOPTS +Obtain the current drive options. +Third argument is a pointer to +.Vt int , containing a bitwise union of the following possible flag values: -.Bl -tag -width FDOPT_NOERRLOG -offset indent -.It Li FDOPT_NORETRY +.Bl -tag -width ".Dv FDOPT_NOERRLOG" +.It Dv FDOPT_NORETRY Do not automatically retry operations upon failure. -.It Li FDOPT_NOERRLOG +.It Dv FDOPT_NOERRLOG Do not cause -.Dq hard error -kernel logs for failed IO operations. -.It Li FDOPT_NOERROR -Do not indicate IO errors when returning from +.Dq "hard error" +kernel logs for failed I/O operations. +.It Dv FDOPT_NOERROR +Do not indicate I/O errors when returning from .Xr read 2 or .Xr write 2 -system calls. The caller is assumed to use -.Li FD_GSTAT -calls in order to inquire about the success of each operation. This +system calls. +The caller is assumed to use +.Dv FD_GSTAT +calls in order to inquire about the success of each operation. +This is intented to allow even erroneous data from bad blocks to be -retrieved using normal IO operations. -.It Li FDOPT_AUTOSEL -Device performs automatic density selection. Unlike the above flags, +retrieved using normal I/O operations. +.It Dv FDOPT_AUTOSEL +Device performs automatic density selection. +Unlike the above flags, this one is read-only. .El -.It Li FD_SOPTS -Set device options, see above for their meaning. Third argument is a +.It Dv FD_SOPTS +Set device options, see above for their meaning. +Third argument is a pointer to -.Li int . +.Vt int . Drive options will always be cleared when closing the descriptor. -.It Li FD_DEBUG -Set the driver debug level. Third argument is a pointer to -.Li int , -level 0 turns off all debugging. Only applicable if the driver has +.It Dv FD_DEBUG +Set the driver debug level. +Third argument is a pointer to +.Vt int , +level 0 turns off all debugging. +Only applicable if the driver has been configured with -.Pp -.Cd options FDC_DEBUG -.It Li FD_CLRERR -Clear the internal low-level error counter. Normally, controller-level -IO errors are only logged up to -.Li FDC_ERRMAX -errors (currently defined to 100). This command resets the counter. +.Cd "options FDC_DEBUG" . +.It Dv FD_CLRERR +Clear the internal low-level error counter. +Normally, controller-level +I/O errors are only logged up to +.Dv FDC_ERRMAX +errors (currently defined to 100). +This command resets the counter. Requires superuser privileges. -.It Li FD_READID -Read one sector ID field from the floppy disk medium. Third argument is +.It Dv FD_READID +Read one sector ID field from the floppy disk medium. +Third argument is a pointer to -.Li struct fdc_readid , -where the read data will be returned. Can be used to analyze a floppy +.Vt "struct fdc_readid" , +where the read data will be returned. +Can be used to analyze a floppy disk medium. -.It Li FD_GSTAT -Return the recent floppy disk controller status, if available. Third +.It Dv FD_GSTAT +Return the recent floppy disk controller status, if available. +Third argument is a pointer to -.Li struct fdc_status , +.Vt "struct fdc_status" , where the status registers (ST0, ST1, ST2, C, H, R, and N) are being returned. -.Ev EINVAL +.Er EINVAL will be caused if no recent status is available. -.It Li FD_GDTYPE -Returns the floppy disk drive type. Third argument is a pointer to -.Li enum fd_drivetype . +.It Dv FD_GDTYPE +Returns the floppy disk drive type. +Third argument is a pointer to +.Vt "enum fd_drivetype" . This type is the same as being used in the per-drive configuration flags, or in the CMOS configuration data on IA32 systems. .El -.Pp .Sh FILES -.Bl -tag -width Pa -compact +.Bl -tag -width ".Pa /dev/fd*" -compact .It Pa /dev/fd* floppy disk device nodes .El .Sh SEE ALSO -.Xr fdcontrol 8 , .Xr fdformat 1 , .Xr fdread 1 , .Xr fdwrite 1 , .Xr ioctl 2 , .Xr open 2 , .Xr read 2 , -.Xr write 2 +.Xr write 2 , +.Xr fdcontrol 8 .Sh AUTHORS +.An -nosplit This man page was initially written by .An Wilko Bulte , and later vastly rewritten by |