because it sets the floppy controller parameters, which requires O_RDWR.
Specifically, the FD_SOPTS ioctl requires this, and the code errors out
and aborts if it can't do it. Among other things, it is changing the
FDOPT_NOERRLOG flag. Broken in 6.0 as well.
fdcontrol/fdcontrol.c:
- Add const constraint to an intermediate value
which is not supposed to be changed elsewhere.
fdread/fdread.c:
- Use _devname in favor of devname to avoid name
conflicit.
- -1 is less than any positive number so in order
to get the block to function, we should get the
block a little earlier.
- Cast to remove signed when we are sure that a
return value is positive, or is compared with
an positive number (tracknumber of a floppy
disk is not likely to have UINT_MAX/2 anyway)
fdread/fdutil.c:
- Use more specific initializer
fdwrite/fdwrite.c:
- Use static on format_track since it's not
referenced in other places.
- Use const char* to represent string constant.
Bump WARNS accordingly.
Centralize the fdctl_wr() function by adding the offset in
the resource to the softc structure.
Bugfix: Read the drive-change signal from the correct place:
same place as the ctl register.
Remove the cdevsw{} related code and implement a GEOM class.
Ditch the state-engine and park a thread on each controller
to service the queue.
Make the interrupt FAST & MPSAFE since it is just a simple
wakeup(9) call.
Rely on a per controller mutex to protect the bioqueues.
Grab GEOMs topology lock when we have to and Giant when
ISADMA needs it. Since all access to the hardware is
isolated in the per controller thread, the rest of the
driver is lock & Giant free.
Create a per-drive queue where requests are parked while
the motor spins up. When the motor is running the requests
are purged to the per controller queue. This allows
requests to other drives to be serviced during spin-up.
Only setup the motor-off timeout when we finish the last
request on the queue and cancel it when a new request
arrives. This fixes the bug in the old code where the motor
turned off while we were still retrying a request.
Make the "drive-change" work reliably. Probe the drive on
first opens. Probe with a recal and a seek to cyl=1 to
reset the drive change line and check again to see if we
have a media.
When we see the media disappear we destroy the geom provider,
create a new one, and flag that autodetection should happen
next time we see a media (unless a specific format is configured).
Add sysctl tunables for a lot of drive related parameters.
If you spend a lot of time waiting for floppies you can
grab the i82078 pdf from Intels web-page and try tuning
these.
Add sysctl debug.fdc.debugflags which will enable various
kinds of debugging printfs.
Add central definitions of our well known floppy formats.
Simplify datastructures for autoselection of format and
call the code at the right times.
Bugfix: Remove at least one piece of code which would have
made 2.88M floppies not work.
Use implied seeks on enhanced controllers.
Use multisector transfers on all controllers. Increase
ISADMA bounce buffers accordingly.
Fall back to single sector when retrying. Reset retry count
on every successful transaction.
Sort functions in a more sensible order and generally tidy
up a fair bit here and there.
Assorted related fixes and adjustments in userland utilities.
WORKAROUNDS:
Do allow r/w opens of r/o media but refuse actual write
operations. This is necessary until the p4::phk_bufwork
branch gets integrated (This problem relates to remounting
not reopening devices, see sys/*/*/${fs}_vfsops.c for details).
Keep PC98's private copy of the old floppy driver compiling
and presumably working (see below).
TODO (planned)
Move probing of drives until after interrupts/timeouts work
(like for ATA/SCSI drives).
TODO (unplanned)
This driver should be made to work on PC98 as well.
Test on YE-DATA PCMCIA floppy drive.
Fix 2.88M media.
This is a MT5 candidate (depends on the bioq_takefirst() addition).
. The main device node now supports automatic density selection for
commonly used media densities. So you can stuff your 1.44 MB and
720 KB media into your drive and just access /dev/fd0, no questions
asked. It's all that easy, isn't it? :)
. Device density handling has been completely overhauled. The old way
of hardwired kernel density knowledge is no longer there. Instead,
the kernel now implements 16 subdevices per drive. The first
subdevice uses automatic density selection, while the remaining 15
devices are freely programmable. They can be assigned an arbitrary
name of the form /dev/fd[:digit]+.[:digit:]{1,4}, where the second
number is meant to either implement device names that are mnemonic
for their raw capacity (as it used to be), or they can alternatively
be created as "anonymous" devices like fd0.1 through fd0.15,
depending on the taste of the administrator. After creating a
subdevice, it is initialized to the maximal native density of the
respective drive type, so it needs to be customized for other
densities by using fdcontrol(8). Pseudo-partition devices (fd0a
through fd0h) are still supported as symlinks.
. The old hack to use flags 0x1 to always assume drive 0 were there is
no longer supported; this is now supposed to be done by wiring the
devices down from the loader via device flags. On IA32
architectures, the first two drives are looked up in the CMOS
configuration records though. On PCMCIA (i. e., the Y-E Data
controller of the Toshiba Libretto), a single drive is always
assumed.
. Other specialities like disabling the FIFO and not probing the drive
at boot-time are selected by per-controller or per-drive flags, too.
. Unit attentions (media has been changed) are supposed to be detected
now; density autoselection only occurs after a unit attention. (Can
be turned off by a per-drive flag, this will cause each Fdopen() to
perform the autoselection.)
. FM floppies can be handled now (on controllers that actually support
it -- not all do these days).
. Fdopen() can be told to avoid density selection by setting
O_NONBLOCK; this leaves the descriptor in a half-opened state where
only a few ioctls are accepted. This is necessary to run fdformat
on a device that uses automatic density selection (since you cannot
autoselect on an unformatted medium, obviously).
. Just differentiate between a plain old NE765 and the enhanced chips,
but don't try more; the existing code was wrong and only misdetected
the chips anyway.
BUGS and TODOs:
. All documentation update still needs to be done.
. Formatting not-so-standard format yields unpredictable results; i
have yet to figure out why this happens. "Standard" formats like
720 and 1440 KB do work, however.
. rc scripts are needed to setup device nodes with nonstandard
densities (like the old /dev/fdN.MMM we used to have).
. Obtaining device flags from the kernel environment doesn't work yet,
thus currently only drives that are present in (IA32) CMOS are
really detected. Someone who knows the odds and ends about device
flags is needed here, i can't figure out what i'm doing wrong.
. 2.88 MB still needs to be done.
Its main purpose is to adapt automatically to the floppy parameters
(in particular the track size for efficient reading), and to allow a
simple error recovery for CRC-errored sectors. Requires the newly
added fdc(4) options.
