xref: /openbmc/linux/Documentation/scsi/dc395x.rst (revision e15a5365)
1.. SPDX-License-Identifier: GPL-2.0
2
3======================================
4README file for the dc395x SCSI driver
5======================================
6
7Status
8------
9The driver has been tested with CD-R and CD-R/W drives. These should
10be safe to use. Testing with hard disks has not been done to any
11great degree and caution should be exercised if you want to attempt
12to use this driver with hard disks.
13
14This is a 2.5 only driver. For a 2.4 driver please see the original
15driver (which this driver started from) at
16http://www.garloff.de/kurt/linux/dc395/
17
18Problems, questions and patches should be submitted to the mailing
19list. Details on the list, including archives, are available at
20http://lists.twibble.org/mailman/listinfo/dc395x/
21
22Parameters
23----------
24The driver uses the settings from the EEPROM set in the SCSI BIOS
25setup. If there is no EEPROM, the driver uses default values.
26Both can be overridden by command line parameters (module or kernel
27parameters).
28
29The following parameters are available:
30
31safe
32   Default: 0, Acceptable values: 0 or 1
33
34   If safe is set to 1 then the adapter will use conservative
35   ("safe") default settings. This sets:
36
37		shortcut for dc395x=7,4,9,15,2,10
38
39adapter_id
40   Default: 7, Acceptable values: 0 to 15
41
42   Sets the host adapter SCSI ID.
43
44max_speed
45   Default: 1, Acceptable value: 0 to 7
46
47   ==  ========
48   0   20   Mhz
49   1   12.2 Mhz
50   2   10   Mhz
51   3   8    Mhz
52   4   6.7  Mhz
53   5   5.8  Hhz
54   6   5    Mhz
55   7   4    Mhz
56   ==  ========
57
58dev_mode
59   Bitmap for device configuration
60
61   DevMode bit definition:
62
63      === ======== ========  =========================================
64      Bit Val(hex) Val(dec)  Meaning
65      === ======== ========  =========================================
66       0    0x01       1     Parity check
67       1    0x02       2     Synchronous Negotiation
68       2    0x04       4     Disconnection
69       3    0x08       8     Send Start command on startup. (Not used)
70       4    0x10      16     Tagged Command Queueing
71       5    0x20      32     Wide Negotiation
72      === ======== ========  =========================================
73
74adapter_mode
75   Bitmap for adapter configuration
76
77   AdaptMode bit definition
78
79    ===== ======== ========  ====================================================
80      Bit Val(hex) Val(dec)  Meaning
81    ===== ======== ========  ====================================================
82       0    0x01       1     Support more than two drives. (Not used)
83       1    0x02       2     Use DOS compatible mapping for HDs greater than 1GB.
84       2    0x04       4     Reset SCSI Bus on startup.
85       3    0x08       8     Active Negation: Improves SCSI Bus noise immunity.
86       4    0x10      16     Immediate return on BIOS seek command. (Not used)
87    (*)5    0x20      32     Check for LUNs >= 1.
88    ===== ======== ========  ====================================================
89
90tags
91   Default: 3, Acceptable values: 0-5
92
93   The number of tags is 1<<x, if x has been specified
94
95reset_delay
96   Default: 1, Acceptable values: 0-180
97
98   The seconds to not accept commands after a SCSI Reset
99
100
101For the built  in driver the parameters should be prefixed with
102dc395x. (eg "dc395x.safe=1")
103
104
105Copyright
106---------
107The driver is free software. It is protected by the GNU General Public
108License (GPL). Please read it, before using this driver. It should be
109included in your kernel sources and with your distribution. It carries the
110filename COPYING. If you don't have it, please ask me to send you one by
111email.
112
113Note: The GNU GPL says also something about warranty and liability.
114Please be aware the following: While we do my best to provide a working and
115reliable driver, there is a chance, that it will kill your valuable data.
116We refuse to take any responsibility for that. The driver is provided as-is
117and YOU USE IT AT YOUR OWN RESPONSIBILITY.
118