this patchset (on hwmon-git) re-introduces superio_locks module,
previously RFC'd here, where I 'borrowed' another thread..
http://marc.info/?l=linux-kernel&m=115821759424601&w=2
The module shares out slots/shared-reservations containing
a mutex, so that multiple modules can coordinate access to
the sio-port.
Im crossposting - LKML for more reviewers, lm-sensors for
folks with the hardware and (perhaps) more interest.
If its not too late, please consider for 2.6.24-rc0
01 - adds superio_locks module
User-drivers specify the sio-port characteristics they can support
device-ids, sio-port-addrs, enter & exit sequences, etc in
a struct superio_search (in __devinit, preferably).
superio_find() then searches existing slots/shared-reservations
for a matching sio-port, and returns it if found.
Otherwize it probes port-addrs, specified by find() user,
and makes and returns a new reservation.
superio_find() finds and reserves the slot,
returned as ptr or null
superio_release() relinguishes the slot (ref-counted)
Once theyve got the reservation in struct superio * gate
(as named in patches 2-5) they *may* use
superio_lock(gate)
superio_enter/exit(gate)
superio_inb/w(gate, regaddr),
superio_outb/w(gate, regaddr, val)
or they can do it themselves with inb/outb, by using gate->sioaddr, etc.
The API names (superio_find etc) were chosen to fit the idiom
used in hwmon/*.c, patches 2-5 remove the per-user-driver
copies of the superio_*() fns.
I added the module to /drivers/hwmon, mostly cuz thats where
Ive used it - perhaps drivers/isa is better ?
02 - use superio-locks in drivers/hwmon/w83627hf.c
tested on an AMD-Barton mobo.
03 - use superio-locks in drivers/hwmon/pc87360
this driver keeps the slot for only during __init, since it
only needs the sio-port to read the ISA addresses of the
Logical Devices in the chip, which are then used exclusively.
04 - use superio-locks in drivers/char/pc8736x_gpio
this driver keeps the slot for the lifetime of the driver
( __init til __exit ), since the driver needs the sio-port
to change pin configurations.
patches 03,04 were tested on a soekris 4801 a year ago,
the box is currently busy. Together they sanity-test
the sharing of a reservation with 2 different life-cycles.
05 - use superio-locks in rest of drivers/hwmon/*.c
this patch is compile-tested only, please review for sanity before you
try running them. Things to look for - missing superio_release(),
opportunities to use superio_devid(), superio_inw(), etc.
Driver sizes:
without/with DEBUG
2364 664 96 3124 c34 drivers/hwmon/superio_locks.ko
2938 664 96 3698 e72 drivers/hwmon/superio_locks.ko
effect on user-driver sizes:
before/after
12209 4004 36 16249 3f79 drivers/hwmon/pc87360.ko
12434 4068 36 16538 409a drivers/hwmon/pc87360.ko
I hope this is small enough; per the link, there apparently are
actual problems (not just theoretical) that this should help with.
OPERATION
The previous thread includes cut-paste from dmesg, from when
I tested on the soekris. No point in repasting here..
RANDOM POINTS/CAVEATS
- Ive not tested the 16-bit device-id check (no hardware)
- superio_(enter|exit) and superio(un)?lock are nearly redundant.
The former also sends the active/idle command sequences, with a tiny
overhead when none are needed (forex the pc87360 chip). One driver
in patch 5 needed a my_superio_enter() due to an odd unlock sequence.
- uses request_region - this might detect a 'rogue' sio-port user
(which requests region, but doesnt use this module).
It did detect a missing superio_release(), which I hacked around
with the paranoid mod-option (easier than rebooting)
- superio-locks.h has static-inline fns, probably not enough
code to do an export for, since >2 sio-ports is probably rare.
- superio_locks may be relevant elsewhere (ACPI ?)
but I havent thought about them, hwmon seemed like a good testcase.
- implements several defaults (byte-sized devid, ldn-addr=7,
devid-addr=20). Perhaps more are possible, as long as theres
an override. I avoided setting the defaults into struct superio_search,
so that it could be const'd.
Please identify those that are standard enough.
This could include #define LPC_* constants, for use in
superio_inb(gate, LPC_LDN), superio_inw(gate, LPC_ISA_ADDR)
then user drivers could just #define SIO_* for non-standard registers.
- Hans, I think Ive added all your suggestions, thanks.
Signed-off-by: Jim Cromie <[email protected]>
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