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From: "Arnd Bergmann" <arnd@arndb.de>
To: "Maciej W. Rozycki" <macro@orcam.me.uk>,
	"Paul Walmsley" <paul.walmsley@sifive.com>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Albert Ou" <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] RISC-V: Make port I/O string accessors actually work
Date: Fri, 23 Sep 2022 12:31:39 +0200	[thread overview]
Message-ID: <c4ee195a-cf1f-44f6-b3b6-241d04e01fb9@www.fastmail.com> (raw)
In-Reply-To: <alpine.DEB.2.21.2209220223080.29493@angie.orcam.me.uk>

On Thu, Sep 22, 2022, at 11:56 PM, Maciej W. Rozycki wrote:
> Fix port I/O string accessors such as `insb', `outsb', etc. which use 
> the physical PCI port I/O address rather than the corresponding memory 
> mapping to get at the requested location, which in turn breaks at least 
> accesses made by our parport driver to a PCIe parallel port such as:
>
> PCI parallel port detected: 1415:c118, I/O at 0x1000(0x1008), IRQ 20
> parport0: PC-style at 0x1000 (0x1008), irq 20, using FIFO 
> [PCSPP,TRISTATE,COMPAT,EPP,ECP]

The patch looks correct to me, but I'm curious: Are you actually
using a parport device on your system, or just testing it to
make it work?

> +#define outsb(addr, buffer, count) __outsb(PCI_IOBASE + (addr), 
> buffer, count)
> +#define outsw(addr, buffer, count) __outsw(PCI_IOBASE + (addr), 
> buffer, count)
> +#define outsl(addr, buffer, count) __outsl(PCI_IOBASE + (addr), 
> buffer, count)
> 

I don't see anything actually risc-v specific in these definitions,
and it would be great to make the asm-generic version do the
right thing here. As far as I can tell, the only difference is
the barriers in the risc-v version, and we should really have the
same in the generic code anyway.

     Arnd

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  reply	other threads:[~2022-09-23 10:32 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-22 21:56 [PATCH] RISC-V: Make port I/O string accessors actually work Maciej W. Rozycki
2022-09-23 10:31 ` Arnd Bergmann [this message]
2022-09-23 11:38   ` Maciej W. Rozycki
2022-10-10 15:41     ` Björn Töpel
2022-10-10 17:53       ` Arnd Bergmann

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