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[83.42.66.34]) by smtp.gmail.com with ESMTPSA id g23sm14093585wmk.14.2019.12.14.05.19.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 14 Dec 2019 05:19:34 -0800 (PST) Subject: Re: [PATCH] mos6522: remove anh register To: Mark Cave-Ayland , Laurent Vivier , David Gibson References: <20191212194359.13508-1-laurent@vivier.eu> <20191213014419.GA207300@umbus.fritz.box> <68431265-fd33-89de-6a61-0c823beaa16e@vivier.eu> <9c731591-3180-d9f8-e5f9-d1b34356664b@ilande.co.uk> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Message-ID: <8de4d817-dacc-73d1-e20b-7b6c533c76d0@redhat.com> Date: Sat, 14 Dec 2019 14:19:33 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <9c731591-3180-d9f8-e5f9-d1b34356664b@ilande.co.uk> Content-Language: en-US X-MC-Unique: kkATIfZ-OHKQwgam24uxPw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org, "Dr . David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 12/14/19 11:47 AM, Mark Cave-Ayland wrote: > On 13/12/2019 08:45, Laurent Vivier wrote: >> Le 13/12/2019 =C3=A0 02:44, David Gibson a =C3=A9crit=C2=A0: >>> On Thu, Dec 12, 2019 at 08:43:59PM +0100, Laurent Vivier wrote: >>>> Register addr 1 is defined as buffer A with handshake (vBufAH), >>>> register addr 15 is also defined as buffer A without handshake (vBufA)= . >>>> >>>> Linux kernel has a big "DON'T USE!" next to the register 1 addr >>>> definition (vBufAH), and only uses register 15 (vBufA). >>>> >>>> So remove the definition of 'anh' and use only 'a' (with VIA_REG_ANH a= nd >>>> VIA_REG_A). >>> >>> I'm not actually following the rationale for removing the register. >>> Linux doesn't use it, but if it's part of the real hardware model we >>> should keep it, no? >> >> It's actually two methods to access the same register (with handshake, >> without handshake). >> >> In the datashit Register 15 is described as "Same as register 1 except >> no handshake". >=20 > Indeed, certainly my reading of the specification was that it was the sam= e register. > I'd be inclined to add qemu_log() at unimp for the handshake registers so= at least we > can easily spot if anything is using them. Agreed, clever than my review suggestion. case VIA_REG_A: + qemu_log_mask(LOG_UNIMP, ...); + /* fall through */ + case VIA_REG_ANH: val =3D s->a; break;