From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 43F473D649D for ; Wed, 15 Apr 2026 17:34:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.168.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776274480; cv=none; b=csje1DN993Cf34InxIPO1x10A+MR7wMO9noBXnT2hCw1E8kSiQCpIz8CSs8D2621yLLGwjCxMSQkwjA/TBLHYBlUlkdWhpaVmEpv0SJL+zDzXU+6+XYhmEOcViFtxABHmLM/F0LfUOt/BUOWibEY1Dt+PcZYjK8BUZdxO9rkxcU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776274480; c=relaxed/simple; bh=PTd4B5uhCcPDIe5w9NIhHzaDs9hz6KZ6USjgaGgCaFQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=IY6Tpt2Jx1p4EE8/Zzq8EI9uCbJIjOQDPqQMeYkDbhEPEaYfdyjvDAf/4+6eIEqswGoQsL//ehVqA2dLqkxTjY53FRIKDPqY33dd0taHWHB4ZIBovvG+FFm9Nwu9iTU9bkLXbe8EiQ0bBkAKMWuTENIhN2vj0b8YoiqB7xx1LQo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com; spf=pass smtp.mailfrom=oss.qualcomm.com; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b=gIzZLNQr; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b=gJZ4Bkep; arc=none smtp.client-ip=205.220.168.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b="gIzZLNQr"; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b="gJZ4Bkep" Received: from pps.filterd (m0279864.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 63FFIXeO4053191 for ; Wed, 15 Apr 2026 17:34:36 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qualcomm.com; h= cc:content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=qcppdkim1; bh= vbR6uymC69o6Z8rsQWYUozstbIH9JlydsnIlYMif8rU=; b=gIzZLNQr3c5GZpCJ DAvLsiqk4yCnL+T32P+6t65uFnVeGd2BAl53FHVbbg2nXX57DxzV55EGKRtYNG69 tUKwuIUPSddrCy95Aofs1v1BEhC+BJiX/rdMX06n+/4vv7GlsdJH2bQVycq62kKi 0osILBVmxC4qNHfKWVjpniLeU+MiN18L25ako0u7QF+P0P9p16DBY0IJs8441zT9 ADJ7dUgvDlK3Qh52UJGE3buGYoT9tMgzv/ugXRs4Tk5EJhrkXGfMXEEJVfMRojvZ 2zezmIw0SvNZr69FLxes7jKlICbPW+dOc1xewDhjWlLgnjTJFMvMmuRnmjUqLb59 K42vQw== Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 4dj7s5st0m-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Wed, 15 Apr 2026 17:34:36 +0000 (GMT) Received: by mail-pl1-f200.google.com with SMTP id d9443c01a7336-2b249975139so143798545ad.0 for ; Wed, 15 Apr 2026 10:34:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oss.qualcomm.com; s=google; t=1776274476; x=1776879276; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=vbR6uymC69o6Z8rsQWYUozstbIH9JlydsnIlYMif8rU=; b=gJZ4BkepBM9+RmfE+zrOBT+xEZ3akPjpEkxLq+HGDoR0J+6kzUerJxPx+HUonn59Dn wH32HfI8wROIiDfPKbUejy9Vbdako5sVwAeJxuQNowZFF4URitcR1a01Ura5/E+CCXgM Ig09Avfw7eGYel5Ts+WDji2NzMaCc0OLbXc6dRPxk86owJuiClYDBLuARizWFQjjpwHb TAQExnh3RZEA+rA/lNLnPS1LQ+LbM19Pf5N7QlFpC7MWXCBxp1+usuNS+E+lVLRsAj7V 71kL+XRsLKbLfb5KFdGSv79yUrjgO2DCjq3+QfpgDTHmGuULuqq67rNQq+CBO1l5wlQ+ 7U2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776274476; x=1776879276; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=vbR6uymC69o6Z8rsQWYUozstbIH9JlydsnIlYMif8rU=; b=EnnSXS8JGMlZmuf5xKkiwp5KBEpdTWySajCgmBJcKxdsFa/fsuWARaWjORcJctZJww GVpPxaa+XVz2iyIHduCNOyK2wJZpaXp1MvkpxUfERxXk+UNBoyhy6vAcxT1aepi3YHGb 2mST+XyUTh5XE0BbzBc9YiBqspQAh1kVKX7+Q9ijzYx4XzNwub/Oz9x+yfPYYvPZIUSw beQd+5mHItOCEyvuE3G5vN0MyX5oDdp01NbjY3KtsFsOMKzQtXiTrGTz/UCmXoiYRhLt nSSK8S0gy8BAn+aeSB8uiBvc0GxI6MmHKwZPLPF42GMeeesS4v34A4OXYfjDvS5vL9ab j3Ng== X-Forwarded-Encrypted: i=1; AFNElJ/PsIQkqQa51+UY6bdkS28x/z1ZYiOHSea3zJTADt5fkopnL/jjV9s0jH+BJqMeuV1vL+qhKRXykvUuZg==@vger.kernel.org X-Gm-Message-State: AOJu0YwI8UWq8xAfuZOthvBQI8/FpLGqfu1YrCmvWadlX2yiC2eTjusP gToLAb6o5pUaaM3NZ6mTsLeJr31sSDo1q6OcKM3FFbBrnTYzzJczBT8/bqrkgbaBekW1J038bw2 j7lDAgbDRQY2Okk7n4EjkhB6tEZp6cgHv5+Tkq9yf6lcvFd/Pb9gWabwENDQaOT0FDQ== X-Gm-Gg: AeBDiesBoW2IRZpnq0yBVTYYGMFRlR/md6jCC5kil3HoMtBWOA+AnyquAC5GT9xbRYD +AGFTrPhkRUfcwD4Nh5p4cx+9QHkSvlJr91sKSLygXHpPolMlqX2oCIwfGthH7hDBL7cACR4vza TBsdXDs4XIFSvodDDj7p4THIInPKc76Bo4TASd4IWDnwvk0NOcFGhs2wHkOjoJziXPLrwIzThuN LTGo7MRcYpw8BAH6JI9ab0VB0rKX8/F75AOUl+p3FYh4YxxRWvBrQ+WMzHxa1pqf8fWzTmECFW4 U3QF7z1hxQtQ0O8yVj3lteimi2dyejMtgBmIRAgyR+sjAC6IEmZGzOWLwTd8IFstWI5bdj8GFL/ CL23RL2CYtN9jJeFeABGRLCV+WMsNDNURkZj9zeM4D4j+Cn9s8YaDaw== X-Received: by 2002:a17:902:6949:b0:2b2:b117:1e16 with SMTP id d9443c01a7336-2b2d5a459ffmr160044675ad.20.1776274475846; Wed, 15 Apr 2026 10:34:35 -0700 (PDT) X-Received: by 2002:a17:902:6949:b0:2b2:b117:1e16 with SMTP id d9443c01a7336-2b2d5a459ffmr160044375ad.20.1776274475300; Wed, 15 Apr 2026 10:34:35 -0700 (PDT) Received: from [10.206.105.200] ([202.46.23.25]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b47810b70csm25397215ad.23.2026.04.15.10.34.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 15 Apr 2026 10:34:34 -0700 (PDT) Message-ID: Date: Wed, 15 Apr 2026 23:04:26 +0530 Precedence: bulk X-Mailing-List: linux-tegra@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH 1/3] drivers: base: Add generic context device bus Content-Language: en-US To: Greg Kroah-Hartman , ekansh.gupta@oss.qualcomm.com Cc: "Rafael J. Wysocki" , Danilo Krummrich , Thierry Reding , Mikko Perttunen , David Airlie , Simona Vetter , Joerg Roedel , Will Deacon , Robin Murphy , Arnd Bergmann , Srinivas Kandagatla , Dmitry Baryshkov , Bharath Kumar , Chenna Kesava Raju , linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, dri-devel@lists.freedesktop.org, linux-tegra@vger.kernel.org, iommu@lists.linux.dev, linux-arm-msm@vger.kernel.org, Vikash Garodia References: <20260414-computebus-v1-0-4d904d40926a@oss.qualcomm.com> <20260414-computebus-v1-1-4d904d40926a@oss.qualcomm.com> <2026041418-volley-composer-6363@gregkh> From: Vishnu Reddy In-Reply-To: <2026041418-volley-composer-6363@gregkh> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Authority-Analysis: v=2.4 cv=A7Zc+aWG c=1 sm=1 tr=0 ts=69dfcc2c cx=c_pps a=IZJwPbhc+fLeJZngyXXI0A==:117 a=ZePRamnt/+rB5gQjfz0u9A==:17 a=IkcTkHD0fZMA:10 a=A5OVakUREuEA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=DJpcGTmdVt4CTyJn9g5Z:22 a=EUspDBNiAAAA:8 a=xRG3GzwA0ZaNjhFdG0MA:9 a=QEXdDO2ut3YA:10 a=uG9DUKGECoFWVXl0Dc02:22 X-Proofpoint-ORIG-GUID: HP1c2lv75NayljpM_qx-CFBSe6XsotHF X-Proofpoint-GUID: HP1c2lv75NayljpM_qx-CFBSe6XsotHF X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNDE1MDE2MyBTYWx0ZWRfX0q/Pov9xnVbM GiQZ5RvOI708QPMCZOMO/My10da9yieROs5w5n/ETDVb2CDZAwSigO+f0OyFs2+/4cCP3rCVJ/A BY23GuWT/oxdZ+KOwb6px0ySzSFZ6oGgObtRcoLeWoQ95NdJNBNJKx5oDWG3qqOCxEML/nEzwu3 Fbjqr/uKdUfND+s2OXm3Ta4LAYvYD+LEzaMA1ze/L4k4PtzH2+ztiMfdnoQ83cg12lZdh94Rl7w hiUtVbWxfNELyskq9xTn0oHQ/LEnxI9voYRq/sKr30YjMqE0b8mMN7bSMMnsQ7IIJpQSdCjyofx 4fndRAAHpP94YwDm8rujPlgkTHUzdKo0uxV3wt2y18YQbZtu2qAA8cLNnKMKtxIKqdAqBsFWXc1 kcgXTbwJCMJJzkU34zWbeqVkKu5StCNw7KahXzlxmeB5Q17UEWeq7l/nOoPg9OzH3/n9ZUk2bax H3MGf3/3Arje8XeoUGg== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-04-15_01,2026-04-13_04,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 spamscore=0 adultscore=0 bulkscore=0 priorityscore=1501 phishscore=0 impostorscore=0 lowpriorityscore=0 suspectscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604070000 definitions=main-2604150163 On 4/14/2026 10:19 PM, Greg Kroah-Hartman wrote: > On Tue, Apr 14, 2026 at 10:01:15PM +0530, Ekansh Gupta via B4 Relay wrote: >> From: Ekansh Gupta >> >> Introduce a new generic bus type for synthetic context bank devices >> that require IOMMU context isolation. This bus provides a shared >> infrastructure for accelerator and GPU drivers that create virtual >> devices representing IOMMU context banks. >> >> Currently, drivers like host1x implement their own bus types for >> context devices. This generic implementation allows multiple drivers >> to share the same bus infrastructure, simplifying the IOMMU subsystem >> integration and reducing code duplication. >> >> Signed-off-by: Ekansh Gupta >> --- >> drivers/base/Kconfig | 3 +++ >> drivers/base/Makefile | 1 + >> drivers/base/context_bus.c | 24 ++++++++++++++++++++++++ >> include/linux/context_bus.h | 15 +++++++++++++++ >> 4 files changed, 43 insertions(+) >> >> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig >> index f7d385cbd3ba..479bc4bb442b 100644 >> --- a/drivers/base/Kconfig >> +++ b/drivers/base/Kconfig >> @@ -4,6 +4,9 @@ menu "Generic Driver Options" >> config AUXILIARY_BUS >> bool >> >> +config CONTEXT_DEVICE_BUS >> + bool > > So this is a context-free bus? I.e. no documentation? > > :) > > This feels really odd, this "bus" isn't doing anything at all. So why > do you need it and can't use auxbus or faux? Looks like the device have specific iommu configuration (via of_dma_configure()), then using the auxbus or faux bus types does not have the bus notifier calls to iommu_release_device(). Please correct me if I misunderstood? > > You say something about an iommu, but yet this has no information about > an iommu at all, so why are they somehow special? > > You need to provide a lot more information here, sorry. > > greg k-h > >