xref: /linux/Documentation/arch/arm/sa1100/serial_uart.rst (revision cdd5b5a9761fd66d17586e4f4ba6588c70e640ea)
1*e790a4ceSJonathan Corbet==================
2*e790a4ceSJonathan CorbetSA1100 serial port
3*e790a4ceSJonathan Corbet==================
4*e790a4ceSJonathan Corbet
5*e790a4ceSJonathan CorbetThe SA1100 serial port had its major/minor numbers officially assigned::
6*e790a4ceSJonathan Corbet
7*e790a4ceSJonathan Corbet  > Date: Sun, 24 Sep 2000 21:40:27 -0700
8*e790a4ceSJonathan Corbet  > From: H. Peter Anvin <hpa@transmeta.com>
9*e790a4ceSJonathan Corbet  > To: Nicolas Pitre <nico@CAM.ORG>
10*e790a4ceSJonathan Corbet  > Cc: Device List Maintainer <device@lanana.org>
11*e790a4ceSJonathan Corbet  > Subject: Re: device
12*e790a4ceSJonathan Corbet  >
13*e790a4ceSJonathan Corbet  > Okay.  Note that device numbers 204 and 205 are used for "low density
14*e790a4ceSJonathan Corbet  > serial devices", so you will have a range of minors on those majors (the
15*e790a4ceSJonathan Corbet  > tty device layer handles this just fine, so you don't have to worry about
16*e790a4ceSJonathan Corbet  > doing anything special.)
17*e790a4ceSJonathan Corbet  >
18*e790a4ceSJonathan Corbet  > So your assignments are:
19*e790a4ceSJonathan Corbet  >
20*e790a4ceSJonathan Corbet  > 204 char        Low-density serial ports
21*e790a4ceSJonathan Corbet  >                   5 = /dev/ttySA0               SA1100 builtin serial port 0
22*e790a4ceSJonathan Corbet  >                   6 = /dev/ttySA1               SA1100 builtin serial port 1
23*e790a4ceSJonathan Corbet  >                   7 = /dev/ttySA2               SA1100 builtin serial port 2
24*e790a4ceSJonathan Corbet  >
25*e790a4ceSJonathan Corbet  > 205 char        Low-density serial ports (alternate device)
26*e790a4ceSJonathan Corbet  >                   5 = /dev/cusa0                Callout device for ttySA0
27*e790a4ceSJonathan Corbet  >                   6 = /dev/cusa1                Callout device for ttySA1
28*e790a4ceSJonathan Corbet  >                   7 = /dev/cusa2                Callout device for ttySA2
29*e790a4ceSJonathan Corbet  >
30*e790a4ceSJonathan Corbet
31*e790a4ceSJonathan CorbetYou must create those inodes in /dev on the root filesystem used
32*e790a4ceSJonathan Corbetby your SA1100-based device::
33*e790a4ceSJonathan Corbet
34*e790a4ceSJonathan Corbet	mknod ttySA0 c 204 5
35*e790a4ceSJonathan Corbet	mknod ttySA1 c 204 6
36*e790a4ceSJonathan Corbet	mknod ttySA2 c 204 7
37*e790a4ceSJonathan Corbet	mknod cusa0 c 205 5
38*e790a4ceSJonathan Corbet	mknod cusa1 c 205 6
39*e790a4ceSJonathan Corbet	mknod cusa2 c 205 7
40*e790a4ceSJonathan Corbet
41*e790a4ceSJonathan CorbetIn addition to the creation of the appropriate device nodes above, you
42*e790a4ceSJonathan Corbetmust ensure your user space applications make use of the correct device
43*e790a4ceSJonathan Corbetname. The classic example is the content of the /etc/inittab file where
44*e790a4ceSJonathan Corbetyou might have a getty process started on ttyS0.
45*e790a4ceSJonathan Corbet
46*e790a4ceSJonathan CorbetIn this case:
47*e790a4ceSJonathan Corbet
48*e790a4ceSJonathan Corbet- replace occurrences of ttyS0 with ttySA0, ttyS1 with ttySA1, etc.
49*e790a4ceSJonathan Corbet
50*e790a4ceSJonathan Corbet- don't forget to add 'ttySA0', 'console', or the appropriate tty name
51*e790a4ceSJonathan Corbet  in /etc/securetty for root to be allowed to login as well.
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