From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lj1-f178.google.com (mail-lj1-f178.google.com [209.85.208.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B5FD2BF016 for ; Fri, 12 Sep 2025 07:22:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757661765; cv=none; b=T0DcreZ11Ns91/SV46djqyRoen9tCW12x1SCIZfiGm4Rax3eeNwSPXCHIeoVEry31SFf0x5QtyQFCO4Dlf0ISym+gOKYZachiUr6L0TeDBoMcmOkPsZmaUIJ1kH8sEB2ltLDTrNUOjAlJYB+aZuACJlVfX7RRbHK0UycjcJeSL8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757661765; c=relaxed/simple; bh=LFFDItX69IfeFYupqtxi699PEVLId8z2psSqs6Xp7Bo=; h=MIME-Version:References:In-Reply-To:From:Date:Message-ID:Subject: To:Cc:Content-Type; b=K34p/DyZJ9nrx5PaL7gECR4P/7MAhduD/oH/qrNZihStwX+CFa4cheAiWc+EcZd8yRd5qjFKsl+PCJqY/H4TUPqmtzhKcDERLlyI8WmpxswuSM6j9WADrfiwO9jePyPLHzuNnz0N02E667trtlSG0PpVQZmDR91s5lNNzWKYRIw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org; spf=pass smtp.mailfrom=linaro.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b=npNBcVD9; arc=none smtp.client-ip=209.85.208.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linaro.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="npNBcVD9" Received: by mail-lj1-f178.google.com with SMTP id 38308e7fff4ca-33c9efd65eeso15279801fa.3 for ; Fri, 12 Sep 2025 00:22:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1757661761; x=1758266561; darn=lists.linux.dev; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=LFFDItX69IfeFYupqtxi699PEVLId8z2psSqs6Xp7Bo=; b=npNBcVD9yxTOQ4udDSJp9rCkqigg8YqmOvxbI2c2XlqGuyx06/aLSAsKoWjVwjMrhw ng4GNdD2L1k6bqYymhcutV69MckfNDzxvhrMl+ONCUq88FOeBw4L9aw7KrWt7nEoK9qV +VmvWI0OzCDTO/qami9/SZOGag6yU4e0Kgt7DeNDsocFsPqfuxu4T7e00J0231b8lIcn HA9OLuQ6p6e3mdgfMWnru6EkwvaPwZN6wbEMi4OOI66+uD5M7c+4PiBRqePyyhp2hfv1 mRirAcx98qJbO3sdtdd5PCk2aOLcQL60qKuE/kdwkTOFYbQBnyOBpB+kQS2ReE5U6LLK Mlxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757661761; x=1758266561; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=LFFDItX69IfeFYupqtxi699PEVLId8z2psSqs6Xp7Bo=; b=q2eE+yrZxZ80wQmO0H/SOwqG0MquL6mIeM/Bf5BiexmlLXQppEJ15wxlbKA6k8KG9P im0pIrBKtc8yMfOzd0bTmaNKU9nGygNUcc8W/8UuPPlMb6jPxea/nEjx1IniZI4SzLHG oDm+Pg+s/MAXYqJOJb1eCU9QnptoumXcc8TpMR5EtpWoTrhLtOPpCAmAc9er6JxM6Dd8 g9CVo64dO4nKcYRboAxvp/7T9+ACsOzVZjFcpcSYlGe4tsDbjmygyXvPZu/7xDw/n1cJ RnoR+I+7FQurBLuEwP4Q8nvn5LwmidcVnyUjXc+BCkLJkW+dseypUi6Havc5X0z245X8 OZ6Q== X-Gm-Message-State: AOJu0YxrnOQoOjyKT73xcv4Mf5QIBvZvsfAaZro3+yrSpuGHEkllH1Ti XMP7VG4Ufk1KdkMzt4ORB0ncB28HEH/Y6pA2p2cT02dgtbpZRJmStYS8CK3hUfY+1xogtTgZuBY ubaZg8zR52kNfzUPtH8eFFeLtsKQX3q2/ME315Un0IQ== X-Gm-Gg: ASbGncunwviA9L/ZxTH9ah8C+DsH49KpuQGBE2sBhc+18N2lwy112S7aRecQAWdNFpT oR0MhK65wilUArh6Kxw92h8xSBrE5JxWN1NecLYHb2oThqlOZ4qJu82/UUYyDmPoR9TEdBYC+iU Z7P4i4OQjBXpiM35HX9GyHQzG4TebM9x+3ricNZSkMoNs1DMWygsky//gn7rpcw93Q/o7gKXaQM rgPi3M= X-Google-Smtp-Source: AGHT+IEpb1Ksju8gX+f7hKclHLv2efeL5F+hA9m3pMOp6ExWKNkaF7ctx9xFmDCAFKq8FR+VV195BmgI4LkeHUUPEvg= X-Received: by 2002:a2e:a988:0:b0:352:46d5:e541 with SMTP id 38308e7fff4ca-35246d5e92amr1938961fa.0.1757661761059; Fri, 12 Sep 2025 00:22:41 -0700 (PDT) Precedence: bulk X-Mailing-List: ksummit@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: In-Reply-To: From: Linus Walleij Date: Fri, 12 Sep 2025 09:22:29 +0200 X-Gm-Features: Ac12FXy_V9Gfmv07XXCdNCSIHJU004gWL0IBTxoXeC4GDkF8qSxbjdkdNUb-s00 Message-ID: Subject: Re: [TECH TOPIC] UALink driver upstreaming To: Konstantin Sinyuk Cc: ksummit@lists.linux.dev, Konstantin Sinyuk Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, Sep 11, 2025 at 8:10=E2=80=AFPM Konstantin Sinyuk wrote: > On Thu, Sep 11, 2025 at 10:42:01AM +0200, Linus Walleij wrote: > > So this gives at hand that since this is no "ordinary" memory-mapped > > driver, it needs its own bus and therefore intuitively its own subsyste= m? > > > > What about drivers/accel/ual where other accelerators live? > > > > Or if that is somehow inappropriate, just drivers/ual, don't be shy. > > Hi Linus, > > For the initial RFC, I thought to start under drivers/misc/ just as a > lightweight entry point to get early review. But I agree with you that > UALink fits more naturally as its own subsystem, similar to how CXL is > handled, rather than being grouped under accel. The long-term plan > should definitely be drivers/ual/. If you want to "ease in" drivers the appropriate place is drivers/staging. But if you have a focused team and you are going to start small and work on this then just use drivers/accel/ual from day 1. Yours, Linus Walleij