1 =========================
2 Mellanox watchdog drivers
3 =========================
4
5 for x86 based system switches
6 =============================
7
8 This driver provides watchdog functionality fo
9 Ethernet and Infiniband switch systems.
10
11 Mellanox watchdog device is implemented in a p
12
13 There are 2 types of HW watchdog implementatio
14
15 Type 1:
16 Actual HW timeout can be defined as a power
17 e.g. timeout 20 sec will be rounded up to 32
18 The maximum timeout period is 32 sec (32768
19 Get time-left isn't supported
20
21 Type 2:
22 Actual HW timeout is defined in sec. and it'
23 a user-defined timeout.
24 Maximum timeout is 255 sec.
25 Get time-left is supported.
26
27 Type 3:
28 Same as Type 2 with extended maximum timeout
29 Maximum timeout is 65535 sec.
30
31 Type 1 HW watchdog implementation exist in old
32 all new systems have type 2 HW watchdog.
33 Two types of HW implementation have also diffe
34
35 Type 3 HW watchdog implementation can exist on
36 with new programmer logic device.
37 It's differentiated by WD capability bit.
38 Old systems still have only one main watchdog.
39
40 Mellanox system can have 2 watchdogs: main and
41 Main and auxiliary watchdog devices can be ena
42 on the same system.
43 There are several actions that can be defined
44 system reset, start fans on full speed and inc
45 The last 2 actions are performed without a sys
46 Actions without reset are provided for auxilia
47 which is optional.
48 Watchdog can be started during a probe, in thi
49 pinged by watchdog core before watchdog device
50 user space application.
51 Watchdog can be initialised in nowayout way, i
52 it can't be stopped.
53
54 This mlx-wdt driver supports both HW watchdog
55
56 Watchdog driver is probed from the common mlx_
57 Mlx_platform driver provides an appropriate se
58 Mellanox watchdog device, identity name (mlx-w
59 initial timeout, performed action in expiratio
60 watchdog configuration flags: nowayout and sta
61 version - type1 or type2.
62 The driver checks during initialization if the
63 was done by the watchdog. If yes, it makes a n
64
65 Access to HW registers is performed through a
66 Programmable logic device registers have littl
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