From: geert@linux-m68k.org (Geert Uytterhoeven)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 0/5] minitty: a minimal TTY layer alternative for embedded systems
Date: Mon, 3 Apr 2017 21:46:08 +0200 [thread overview]
Message-ID: <CAMuHMdVowagRdRVN8eNcbb2WKCQewNxRMGd02s2YMmX0drwQGQ@mail.gmail.com> (raw)
In-Reply-To: <CAL_JsqJh-X_5Dq81vwNWo5txZSC8uQETPTAPS4DPeTh2bDKkwg@mail.gmail.com>
On Mon, Apr 3, 2017 at 8:57 PM, Rob Herring <robh@kernel.org> wrote:
> On Mon, Apr 3, 2017 at 1:14 PM, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>> On Mon, Apr 3, 2017 at 12:44 AM, Stuart Longland
>> <stuartl@longlandclan.id.au> wrote:
>>> On 03/04/17 07:41, Nicolas Pitre wrote:
>>>>> No PTYs seems like a big limitation. This means no sshd?
>>>> Again, my ultimate system target is in the sub-megabyte of RAM. I
>>>> really doubt you'll be able to fit an SSH server in there even if PTYs
>>>> were supported, unless sshd (or dropbear) can be made really tiny.
>>>> Otherwise you most probably have sufficient resources to run the regular
>>>> TTY code.
>>>
>>> Are we talking small microcontrollers here? The smallest machine in
>>> terms of RAM I ever recall running Linux on was a 386SX/25 MHz with 4MB
>>> RAM, and that had a MMU.
>>
>> Let's halve that. I once tried and ran Linux in 2 MiB, incl. X, twm, and xterm.
>> Of course with swap enabled. And swapping like hell.
>
> These are different target uses. We're talking about fixed function,
> statically linked user space at the minimum (some may want no
> userspace even). Applications that could use an RTOS instead but
> benefit from the Linux hardware support, features and ecosystem. It's
> not a whole new code base or environment to learn. Maybe Zephyr will
> have traction and improve things, but projects I've been involved with
> using RTOSs generally have discussions around needing to re-write the
> crappy RTOS.
Sure. I just wanted to point out that there was a time you could have
_more_ than you need for small fixed function embedded systems in
2 MiB of RAM.
> The absolute amount of RAM target is not so important. What's
> important is getting to a size feasible for onchip RAM. That's always
> moving (up), but has generally been out of reach for Linux.
DigiKey shows 39 ARM SoCs with 1 MiB or more of RAM.
But once you want 3 MiB or more, the lone winner is Renesas' RZ/A1 (up to
10 MiB).
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2017-04-03 19:46 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-01 22:21 [PATCH v2 0/5] minitty: a minimal TTY layer alternative for embedded systems Nicolas Pitre
2017-04-01 22:21 ` [PATCH v2 1/5] console: move console_init() out of tty_io.c Nicolas Pitre
2017-04-01 22:21 ` [PATCH v2 2/5] tty: move baudrate handling code to a file of its own Nicolas Pitre
2017-04-01 22:21 ` [PATCH v2 3/5] serial: small Makefile reordering Nicolas Pitre
2017-04-02 12:55 ` Andy Shevchenko
2017-04-02 15:49 ` Nicolas Pitre
2017-04-01 22:21 ` [PATCH v2 4/5] serial: split generic UART driver helper functions into a separate file Nicolas Pitre
2017-04-02 13:16 ` Andy Shevchenko
2017-04-02 15:44 ` Nicolas Pitre
2017-04-03 7:35 ` kbuild test robot
2017-04-01 22:21 ` [PATCH v2 5/5] minitty: minimal TTY support alternative for serial ports Nicolas Pitre
2017-04-02 13:22 ` [PATCH v2 0/5] minitty: a minimal TTY layer alternative for embedded systems Andy Shevchenko
2017-04-02 15:55 ` Nicolas Pitre
2017-04-03 12:56 ` Alan Cox
2017-04-03 16:06 ` Nicolas Pitre
2017-04-03 18:05 ` Alan Cox
2017-04-03 19:50 ` Nicolas Pitre
2017-04-04 13:40 ` Alan Cox
2017-04-04 19:26 ` Nicolas Pitre
2017-04-02 20:47 ` Andi Kleen
2017-04-02 21:41 ` Nicolas Pitre
2017-04-02 22:44 ` Stuart Longland
2017-04-03 1:01 ` Nicolas Pitre
2017-04-04 0:39 ` Stuart Longland
2017-04-03 18:14 ` Geert Uytterhoeven
2017-04-03 18:57 ` Rob Herring
2017-04-03 19:46 ` Geert Uytterhoeven [this message]
2017-04-03 21:05 ` Andy Shevchenko
2017-04-04 16:59 ` Tom Zanussi
2017-04-04 17:08 ` Andy Shevchenko
2017-04-04 17:59 ` Tom Zanussi
2017-04-04 18:04 ` Andy Shevchenko
2017-04-04 18:31 ` Nicolas Pitre
2017-04-04 19:58 ` Tom Zanussi
2017-04-04 20:27 ` Nicolas Pitre
2017-04-04 18:53 ` Nicolas Pitre
2017-04-03 7:54 ` Andy Shevchenko
2017-04-03 15:31 ` Andi Kleen
2017-04-03 17:27 ` Nicolas Pitre
2017-04-03 19:57 ` Adam Borowski
2017-04-03 20:09 ` Nicolas Pitre
2017-04-03 20:32 ` Adam Borowski
2017-04-03 16:40 ` Nicolas Pitre
2017-04-03 7:44 ` Greg Kroah-Hartman
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