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Diffstat (limited to 'Documentation/scsi/megaraid.txt')
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diff --git a/Documentation/scsi/megaraid.txt b/Documentation/scsi/megaraid.txt deleted file mode 100644 index 3c7cea51e687..000000000000 --- a/Documentation/scsi/megaraid.txt +++ /dev/null @@ -1,70 +0,0 @@ - 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. |