[PATCH] RFC: ARM: dts: Proposed Goramo MultiLink device tree

[Krzysztof Hałasa]

Hi Linus,

First, thanks for your continued work on those old platforms.

I'm not exactly sure how to proceed.

> It requires writing a new 74hc4094 GPIO driver and moving a bunch
> of the boardfile code into the HSS driver as it is anyways the only
> user of this facility. If there are other boards supporting HSS they
> can be added too.

I'm not aware of any other supported hw using HSS.

The 74HC4094... I appears it's used mostly for HSS (optional signals
depending on the hardware port version), but one of it's outputs drives
PCI reset as well. There is also /write-protect for a couple of serial
EEPROMs (one of them usually not installed). AFAIR the EEPROMs were
never used for anything, but were available for some custom sw etc.
Also, the EEPROM(s) should be functional without driving 74HC4094, they
would only be unprotected (the protection wouldn't be needed in
practically all cases anyway).

> To proceed with this I need to be sure someone is willing to test
> and help develop this and has interest in supporting the Goramo
> MultiLink with recent kernels on e.g. OpenWrt.

TBH, the last time I was running such a device it was using a kernel
within something like 3.1x range. I *think* I still have some of the
hardware (definitely not all types, but perhaps one of the later
versions). Also, I think I should have some serial sync hardware, so in
theory both the DTS conversion and the HSS operation could be tested.

OTOH I don't know if it's worth the effort. But, since you already wrote
the DTS file, perhaps it's better to just leave it in place (knowing
that certain functionality of certain versions will be unavailable). If
I can test and possibly fix something here, I will try to.

The following is:
Acked-by: Krzysztof Hałasa <khalasa at piap.pl>

Some notes:

> +++ b/arch/arm/boot/dts/intel-ixp42x-goramo-multilink.dts
> @@ -0,0 +1,201 @@
> +// SPDX-License-Identifier: ISC
> +/*
> + * Device Tree file for the Goramo MultiLink Router
> + * There are two variants:
> + * - MultiLink Basic (a box)
> + * - MultiLink Max (19" rack mount)

The Max was usually not 19" rack version, it's the same circa 10" plastic
box as the basic (base?). The 19" case was available independently of
the router hw version (well, not for "micro" version).

As I remember it:
- there was MultiLink Micro: a small router module mounted inside
  a DSL-class modem. At least 2 versions, with small differences (maybe
  number of Ethernet ports or something like this). 32 MB of RAM, the
  latter were using (I think) 64 MB. HSS V.35 connector, the other HSS
  was used by the modem. No PCI, no USB.

- Basic: it had 64 MB of RAM. Standalone plastic box. 2 10/100 Ethernets
  (built-in, using LXT971 phy - in newer versions (v. 2.x) 2 additional
  optional Intel PCI 10/100 Mbps Ethernets). 2 HSS ports (usually V.35
  but could be configured, in hardware, as - I imagine - X.21, and even
  as T1 or E1 with additional PHY).

- Max: Basic on steroids. 128 MB of RAM (optionally 256 MB), mini PCI
  slot (mostly for WiFi).
  Original version: NEC USB 2.0 host controller (2 ports).
  Newer versions: IDE (PATA) connector, 4 USB 2.0 ports, all provided by
  a CS5536 ("Geode compation chip"). I *think* Basic version lacked this
  CS5536 (and Basic v. 1.0 lacked NEC USB). Also 2 Intel PCI Gigabit
  Ethernets.

All of those hw details were described in a config record in the flash.

> + * This device tree supports MultiLink Basic.
> + * This machine is based on IXP425.
> + * This is one of the few devices supporting the IXP4xx High-Speed Serial
> + * (HSS) link for a V.35 WAN interface.
> + * The hardware seems to originate in Poland.

s/seems to originate/originated/ :-)

> +		/*
> +		 * The Goramo MultiLink Router uses different txready queues than any other router,
> +		 * which makes it likely that it uses non-default firmware for the NPE units.
> +		 */

It used standard firmware, the txready queue # was configurable in
software. I guess it was different from other boards to avoid some
conflict with HSS.
IIRC the queue numbers changed at some point with firmware version.
But all those boards (not only Goramo MultiLinks but generally all
IXP4xx) were supposed to use the last firmware available.
-- 
Krzysztof "Chris" Hałasa

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