[GitHub/mt8127/android_kernel_alcatel_ttab.git] / Documentation / cciss.txt

This driver is for Compaq's SMART Array Controllers.

Supported Cards:
----------------

This driver is known to work with the following cards:

	* SA 5300
	* SA 5i 
	* SA 532
	* SA 5312
	* SA 641
	* SA 642
	* SA 6400
	* SA 6400 U320 Expansion Module
	* SA 6i
	* SA P600
	* SA P800
	* SA E400
	* SA E300

If nodes are not already created in the /dev/cciss directory, run as root:

# cd /dev
# ./MAKEDEV cciss

Device Naming:
--------------

You need some entries in /dev for the cciss device.  The MAKEDEV script
can make device nodes for you automatically.  Currently the device setup
is as follows:

Major numbers:
	104	cciss0	
	105	cciss1	
	106	cciss2
	105	cciss3
	108	cciss4
	109	cciss5
	110	cciss6
	111	cciss7

Minor numbers:
        b7 b6 b5 b4 b3 b2 b1 b0
        |----+----| |----+----|
             |           |
             |           +-------- Partition ID (0=wholedev, 1-15 partition)
             |
             +-------------------- Logical Volume number

The device naming scheme is:
/dev/cciss/c0d0			Controller 0, disk 0, whole device
/dev/cciss/c0d0p1		Controller 0, disk 0, partition 1
/dev/cciss/c0d0p2		Controller 0, disk 0, partition 2
/dev/cciss/c0d0p3		Controller 0, disk 0, partition 3

/dev/cciss/c1d1			Controller 1, disk 1, whole device
/dev/cciss/c1d1p1		Controller 1, disk 1, partition 1
/dev/cciss/c1d1p2		Controller 1, disk 1, partition 2
/dev/cciss/c1d1p3		Controller 1, disk 1, partition 3

SCSI tape drive and medium changer support
------------------------------------------

SCSI sequential access devices and medium changer devices are supported and 
appropriate device nodes are automatically created.  (e.g.  
/dev/st0, /dev/st1, etc.  See the "st" man page for more details.) 
You must enable "SCSI tape drive support for Smart Array 5xxx" and 
"SCSI support" in your kernel configuration to be able to use SCSI
tape drives with your Smart Array 5xxx controller.

Additionally, note that the driver will not engage the SCSI core at init 
time.  The driver must be directed to dynamically engage the SCSI core via 
the /proc filesystem entry which the "block" side of the driver creates as 
/proc/driver/cciss/cciss* at runtime.  This is because at driver init time, 
the SCSI core may not yet be initialized (because the driver is a block 
driver) and attempting to register it with the SCSI core in such a case 
would cause a hang.  This is best done via an initialization script 
(typically in /etc/init.d, but could vary depending on distibution). 
For example:

	for x in /proc/driver/cciss/cciss[0-9]*
	do
		echo "engage scsi" > $x
	done

Once the SCSI core is engaged by the driver, it cannot be disengaged 
(except by unloading the driver, if it happens to be linked as a module.)

Note also that if no sequential access devices or medium changers are
detected, the SCSI core will not be engaged by the action of the above
script.

Hot plug support for SCSI tape drives
-------------------------------------

Hot plugging of SCSI tape drives is supported, with some caveats.
The cciss driver must be informed that changes to the SCSI bus
have been made, in addition to and prior to informing the SCSI 
mid layer.  This may be done via the /proc filesystem.  For example:

	echo "rescan" > /proc/scsi/cciss0/1

This causes the adapter to query the adapter about changes to the 
physical SCSI buses and/or fibre channel arbitrated loop and the 
driver to make note of any new or removed sequential access devices
or medium changers.  The driver will output messages indicating what 
devices have been added or removed and the controller, bus, target and 
lun used to address the device.  Once this is done, the SCSI mid layer 
can be informed of changes to the virtual SCSI bus which the driver 
presents to it in the usual way. For example: 

	echo scsi add-single-device 3 2 1 0 > /proc/scsi/scsi
 
to add a device on controller 3, bus 2, target 1, lun 0.   Note that
the driver makes an effort to preserve the devices positions
in the virtual SCSI bus, so if you are only moving tape drives 
around on the same adapter and not adding or removing tape drives 
from the adapter, informing the SCSI mid layer may not be necessary.

Note that the naming convention of the /proc filesystem entries 
contains a number in addition to the driver name.  (E.g. "cciss0" 
instead of just "cciss" which you might expect.)

Note: ONLY sequential access devices and medium changers are presented 
as SCSI devices to the SCSI mid layer by the cciss driver.  Specifically, 
physical SCSI disk drives are NOT presented to the SCSI mid layer.  The 
physical SCSI disk drives are controlled directly by the array controller 
hardware and it is important to prevent the kernel from attempting to directly
access these devices too, as if the array controller were merely a SCSI 
controller in the same way that we are allowing it to access SCSI tape drives.
Commit	Line	Data
1da177e4 LT	1	This driver is for Compaq's SMART Array Controllers.
	2
	3	Supported Cards:
	4	----------------
	5
	6	This driver is known to work with the following cards:
	7
	8	* SA 5300
	9	* SA 5i
	10	* SA 532
	11	* SA 5312
	12	* SA 641
	13	* SA 642
	14	* SA 6400
	15	* SA 6400 U320 Expansion Module
	16	* SA 6i
	17	* SA P600
	18	* SA P800
	19	* SA E400
3de0a70b	20	* SA E300
1da177e4 LT	21
	22	If nodes are not already created in the /dev/cciss directory, run as root:
	23
	24	# cd /dev
	25	# ./MAKEDEV cciss
	26
	27	Device Naming:
	28	--------------
	29
	30	You need some entries in /dev for the cciss device. The MAKEDEV script
	31	can make device nodes for you automatically. Currently the device setup
	32	is as follows:
	33
	34	Major numbers:
	35	104 cciss0
	36	105 cciss1
	37	106 cciss2
	38	105 cciss3
	39	108 cciss4
	40	109 cciss5
	41	110 cciss6
	42	111 cciss7
	43
	44	Minor numbers:
	45	b7 b6 b5 b4 b3 b2 b1 b0
	46	\|----+----\| \|----+----\|
	47	\| \|
	48	\| +-------- Partition ID (0=wholedev, 1-15 partition)
	49	\|
	50	+-------------------- Logical Volume number
	51
	52	The device naming scheme is:
	53	/dev/cciss/c0d0 Controller 0, disk 0, whole device
	54	/dev/cciss/c0d0p1 Controller 0, disk 0, partition 1
	55	/dev/cciss/c0d0p2 Controller 0, disk 0, partition 2
	56	/dev/cciss/c0d0p3 Controller 0, disk 0, partition 3
	57
	58	/dev/cciss/c1d1 Controller 1, disk 1, whole device
	59	/dev/cciss/c1d1p1 Controller 1, disk 1, partition 1
	60	/dev/cciss/c1d1p2 Controller 1, disk 1, partition 2
	61	/dev/cciss/c1d1p3 Controller 1, disk 1, partition 3
	62
	63	SCSI tape drive and medium changer support
	64	------------------------------------------
	65
	66	SCSI sequential access devices and medium changer devices are supported and
	67	appropriate device nodes are automatically created. (e.g.
	68	/dev/st0, /dev/st1, etc. See the "st" man page for more details.)
	69	You must enable "SCSI tape drive support for Smart Array 5xxx" and
	70	"SCSI support" in your kernel configuration to be able to use SCSI
	71	tape drives with your Smart Array 5xxx controller.
	72
	73	Additionally, note that the driver will not engage the SCSI core at init
	74	time. The driver must be directed to dynamically engage the SCSI core via
	75	the /proc filesystem entry which the "block" side of the driver creates as
	76	/proc/driver/cciss/cciss* at runtime. This is because at driver init time,
	77	the SCSI core may not yet be initialized (because the driver is a block
	78	driver) and attempting to register it with the SCSI core in such a case
	79	would cause a hang. This is best done via an initialization script
	80	(typically in /etc/init.d, but could vary depending on distibution).
	81	For example:
	82
	83	for x in /proc/driver/cciss/cciss[0-9]*
	84	do
85	echo "engage scsi" > $x
86	done
87
88	Once the SCSI core is engaged by the driver, it cannot be disengaged
89	(except by unloading the driver, if it happens to be linked as a module.)
90
91	Note also that if no sequential access devices or medium changers are
92	detected, the SCSI core will not be engaged by the action of the above
93	script.
94
95	Hot plug support for SCSI tape drives
96	-------------------------------------
97
98	Hot plugging of SCSI tape drives is supported, with some caveats.
99	The cciss driver must be informed that changes to the SCSI bus
100	have been made, in addition to and prior to informing the SCSI
101	mid layer. This may be done via the /proc filesystem. For example:
102
103	echo "rescan" > /proc/scsi/cciss0/1
104
105	This causes the adapter to query the adapter about changes to the
106	physical SCSI buses and/or fibre channel arbitrated loop and the
107	driver to make note of any new or removed sequential access devices
108	or medium changers. The driver will output messages indicating what
109	devices have been added or removed and the controller, bus, target and
110	lun used to address the device. Once this is done, the SCSI mid layer
111	can be informed of changes to the virtual SCSI bus which the driver
112	presents to it in the usual way. For example:
113
114	echo scsi add-single-device 3 2 1 0 > /proc/scsi/scsi
115
116	to add a device on controller 3, bus 2, target 1, lun 0. Note that
117	the driver makes an effort to preserve the devices positions
118	in the virtual SCSI bus, so if you are only moving tape drives
119	around on the same adapter and not adding or removing tape drives
120	from the adapter, informing the SCSI mid layer may not be necessary.
121
122	Note that the naming convention of the /proc filesystem entries
123	contains a number in addition to the driver name. (E.g. "cciss0"
124	instead of just "cciss" which you might expect.)
125
126	Note: ONLY sequential access devices and medium changers are presented
127	as SCSI devices to the SCSI mid layer by the cciss driver. Specifically,
128	physical SCSI disk drives are NOT presented to the SCSI mid layer. The
129	physical SCSI disk drives are controlled directly by the array controller
130	hardware and it is important to prevent the kernel from attempting to directly
131	access these devices too, as if the array controller were merely a SCSI
132	controller in the same way that we are allowing it to access SCSI tape drives.
133