mirror of
https://github.com/torvalds/linux.git
synced 2024-11-08 21:21:47 +00:00
2fe0ae78c6
This patch fixes typos in various Documentation txts. The patch addresses some words starting with the letters 'H'-'M'. Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Adrian Bunk <bunk@stusta.de>
71 lines
3.0 KiB
Plaintext
71 lines
3.0 KiB
Plaintext
Notes on Management Module
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Overview:
|
|
--------
|
|
|
|
Different classes of controllers from LSI Logic accept and respond to the
|
|
user applications in a similar way. They understand the same firmware control
|
|
commands. Furthermore, the applications also can treat different classes of
|
|
the controllers uniformly. Hence it is logical to have a single module that
|
|
interfaces with the applications on one side and all the low level drivers
|
|
on the other.
|
|
|
|
The advantages, though obvious, are listed for completeness:
|
|
|
|
i. Avoid duplicate code from the low level drivers.
|
|
ii. Unburden the low level drivers from having to export the
|
|
character node device and related handling.
|
|
iii. Implement any policy mechanisms in one place.
|
|
iv. Applications have to interface with only module instead of
|
|
multiple low level drivers.
|
|
|
|
Currently this module (called Common Management Module) is used only to issue
|
|
ioctl commands. But this module is envisioned to handle all user space level
|
|
interactions. So any 'proc', 'sysfs' implementations will be localized in this
|
|
common module.
|
|
|
|
Credits:
|
|
-------
|
|
|
|
"Shared code in a third module, a "library module", is an acceptable
|
|
solution. modprobe automatically loads dependent modules, so users
|
|
running "modprobe driver1" or "modprobe driver2" would automatically
|
|
load the shared library module."
|
|
|
|
- Jeff Garzik (jgarzik@pobox.com), 02.25.2004 LKML
|
|
|
|
"As Jeff hinted, if your userspace<->driver API is consistent between
|
|
your new MPT-based RAID controllers and your existing megaraid driver,
|
|
then perhaps you need a single small helper module (lsiioctl or some
|
|
better name), loaded by both mptraid and megaraid automatically, which
|
|
handles registering the /dev/megaraid node dynamically. In this case,
|
|
both mptraid and megaraid would register with lsiioctl for each
|
|
adapter discovered, and lsiioctl would essentially be a switch,
|
|
redirecting userspace tool ioctls to the appropriate driver."
|
|
|
|
- Matt Domsch, (Matt_Domsch@dell.com), 02.25.2004 LKML
|
|
|
|
Design:
|
|
------
|
|
|
|
The Common Management Module is implemented in megaraid_mm.[ch] files. This
|
|
module acts as a registry for low level hba drivers. The low level drivers
|
|
(currently only megaraid) register each controller with the common module.
|
|
|
|
The applications interface with the common module via the character device
|
|
node exported by the module.
|
|
|
|
The lower level drivers now understand only a new improved ioctl packet called
|
|
uioc_t. The management module converts the older ioctl packets from the older
|
|
applications into uioc_t. After driver handles the uioc_t, the common module
|
|
will convert that back into the old format before returning to applications.
|
|
|
|
As new applications evolve and replace the old ones, the old packet format
|
|
will be retired.
|
|
|
|
Common module dedicates one uioc_t packet to each controller registered. This
|
|
can easily be more than one. But since megaraid is the only low level driver
|
|
today, and it can handle only one ioctl, there is no reason to have more. But
|
|
as new controller classes get added, this will be tuned appropriately.
|