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 <jim.cromie at gmail.com> ---
