[lkml]   [2000]   [Sep]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: Russell King forks ARM Linux.
On Wed, Sep 27, 2000 at 02:30:13PM -0700, H. Peter Anvin wrote:
> For what it's worth, the SA1100 serial driver has been registered with
> me on the Low-Density Serial Ports major (204) as /dev/ttySA0-2 (minor
> 5-7).
> Russ is 100% correct that different drivers shouldn't use the
> same device numbers, unless they are:
> a) mutually exclusive,
> b) interface compatible, *AND*
> c) handle all arbitration necessary.
> If (a), (b) and (c) are all satisfied, it is often justified to share
> device numbers and device nodes.

I jumped into this discussion on linux-arm-kernel before realizing
it had wandered here.

I don't see the major 204 allocation in devices.txt, so I'm not sure if
this has already been covered, but it would be nice to have an allocation
for "on-chip UARTs" in system-on-chip type configurations. I recently
worked on a port to the Cirrus Logic EP7211, which is an ARM-based
system-on-chip (CPU, UARTs, LCD controller, DRAM controller, etc.)
It seems hoggish to ask for an allocation for such a non-general-purpose
piece of hardware.

If we had (say) 4 or 8 on-chip UART device numbers for regular serial,
plus a corresponding 4 or 8 for serial IR using the same UARTs, that
would cover things nicely (EP7211 has only 2 UARTs but I figure it'll be
good to leave some room). And on-chip UARTs are by definition mutually
exclusive (unless you start talking about sharing /dev via NFS between
heterogeneous embedded systems).


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
Please read the FAQ at

 \ /
  Last update: 2005-03-22 12:38    [W:0.098 / U:2.760 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site