Message-ID: <8bc77a68-ec04-863e-0c46-1ea442e392ee@schinagl.nl>
Date:   Sun, 19 Feb 2023 17:07:34 +0100
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Subject: Re: [PATCH] mips: Realtek RTL: select NO_EXCEPT_FILL
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To:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc:     Sander Vanheule <sander@svanheule.net>, linux-mips@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20230115121922.6359-1-sander@svanheule.net>
 <20230127162755.GB6090@alpha.franken.de>
 <46724036-fabf-7bae-41f8-1e95c5f1db5c@schinagl.nl>
 <20230205161929.GD4459@alpha.franken.de>
 <f9c1be9c-478e-55e8-ad34-370641181015@schinagl.nl>
 <20230217173708.GA14134@alpha.franken.de>
 <af2cdad5-ee32-7956-cd77-2a18777a3857@schinagl.nl>
 <20230219090248.GE2924@alpha.franken.de>
 <54238ab7-b7c0-a3a3-38e9-f7879866fb3c@schinagl.nl>
 <20230219103112.GA4095@alpha.franken.de>
From:   Olliver Schinagl <oliver@schinagl.nl>
In-Reply-To: <20230219103112.GA4095@alpha.franken.de>
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Hey Thomas,

On 19-02-2023 11:31, Thomas Bogendoerfer wrote:
> On Sun, Feb 19, 2023 at 10:27:17AM +0100, Olliver Schinagl wrote:
>> It's still odd though; as we do not have _anything_ PCI, but it
>> SWAP_IO_SPACE causes the crash.
> 
> but something uses readX/write() calls. If you aren't using any driver
> existing driver but only newly written dedicated for that SOC
> you could use raw_read/raw_writeX() instead. These type of functions
> are always using native endianess.

Ok that is valueable information. I think currently the only driver 
(that I can think of right now) that we use 'off the shelf' is the uart 
driver, so I hope that's written cleanly :)

As for readX/writeX, for sure that is being used, and I intended to 
refactor that while going to proper and clean drivers (the realtek 
support in openwrt is a big mess right now).

So you say raw_readX, but what about ioread32 which I thought was preferred?

I'll meanwhile read into what readX vs raw_readX to learn more with 
regards to endianess.

Thank you so mcuh so far!

> 
>> What makes SWAP_IO_SPACE generic then? :)
> 
> als long as hardware presents memory used with readX/writeX is
> seen as little endian independant from CPU endianess it's generic.

'little endian independent'? What does that mean, that the register maps 
follow the CPU endianess?

> 
> Thomas.
>