From: David Daney <ddaney.cavm@gmail.com>
To: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Paul Martin <paul.martin@codethink.co.uk>, linux-mips@linux-mips.org
Subject: Re: [PATCH 0/6] MIPS: OCTEON: Patches to enable Little Endian
Date: Mon, 16 Mar 2015 12:44:50 -0700 [thread overview]
Message-ID: <550732B2.6020104@gmail.com> (raw)
In-Reply-To: <20150316192704.GC586@fuloong-minipc.musicnaut.iki.fi>
On 03/16/2015 12:27 PM, Aaro Koskinen wrote:
> Hi,
>
> On Mon, Mar 16, 2015 at 10:39:40AM +0000, Paul Martin wrote:
>> On Fri, Mar 13, 2015 at 08:52:58PM +0200, Aaro Koskinen wrote:
>>> Hi,
>>>
>>> On Fri, Mar 13, 2015 at 05:34:52PM +0000, Paul Martin wrote:
>>>> Octeon II CPUs can switch from Big Endian to Little Endian freely
>>>> even in kernel/supervisor mode.
>>>
>>> You are enabling it on all OCTEONS. Is that valid? At least octeon-usb
>>> still needs to be fixed for little-endian mode.
>>
>> The USB works perfectly with the patches that were posted to this list
>> over the last couple of months.
>
> I was referring to driver for OCTEON+ USB controller in staging.
> ERPro uses EHCI, so it's different. Anyway, I can try to fix the most
> obvious issues myself e.g. bitfields.
>
OCTEON Plus CPUs (i.e. those with afore mentioned USB controller) don't
really support Little-Endian operation, so it may not be worth doing
anything with that driver.
There are several problems:
1) The system bootloader (u-boot) must have support for booting
Little-Endian. EdgeRouter LITE doesn't have the proper support. In
theory you could write a LE booting shim, but I am too lazy to explain
what it must do...
2) The bootbus controller doesn't work in LittleEndian mode on OCTEON-Plus.
3) It has never been tested due to #2 being somewhat of a show stopper.
David Daney
> A.
>
>
>
next prev parent reply other threads:[~2015-03-16 19:44 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-13 17:34 [PATCH 0/6] MIPS: OCTEON: Patches to enable Little Endian Paul Martin
2015-03-13 17:34 ` [PATCH 1/6] MIPS: OCTEON: Tell the kernel build system we can do " Paul Martin
2015-03-13 17:48 ` Sergei Shtylyov
2015-03-13 18:37 ` Aaro Koskinen
2015-03-13 17:34 ` [PATCH 2/6] MIPS: OCTEON: Ensure CPUs come up little endian Paul Martin
2015-03-13 18:44 ` Aaro Koskinen
2015-03-13 17:34 ` [PATCH 3/6] MIPS: OCTEON: Turn hardware bitfields and structures inside out Paul Martin
2015-03-13 17:34 ` [PATCH 4/6] MIPS: OCTEON: Set appropriate endianness in L2C registers Paul Martin
2015-03-13 17:34 ` [PATCH 5/6] MIPS: OCTEON: Reverse the order of register accesses to the FAU Paul Martin
2015-03-13 17:34 ` [PATCH 6/6] MIPS: OCTEON: Set up ethernet hardware for little endian Paul Martin
2015-03-13 18:52 ` [PATCH 0/6] MIPS: OCTEON: Patches to enable Little Endian Aaro Koskinen
2015-03-16 10:39 ` Paul Martin
2015-03-16 19:27 ` Aaro Koskinen
2015-03-16 19:44 ` David Daney [this message]
2015-03-16 21:10 ` Aaro Koskinen
2015-03-16 22:02 ` David Daney
2015-03-16 14:57 ` Paul Martin
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