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Tue, 14 Apr 2026 02:45:33 -0700 (PDT) X-Received: by 2002:a17:902:cf0d:b0:2b0:5cb3:e4bc with SMTP id d9443c01a7336-2b2d59ae7cemr166707295ad.16.1776159932546; Tue, 14 Apr 2026 02:45:32 -0700 (PDT) Received: from [10.217.219.169] ([202.46.22.19]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b2d4f2f8e7sm134928975ad.65.2026.04.14.02.45.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 14 Apr 2026 02:45:32 -0700 (PDT) Message-ID: <5a2fa53c-a895-4c39-9670-c6d383ca17a6@oss.qualcomm.com> Date: Tue, 14 Apr 2026 15:15:27 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 2/9] bus: mhi: Move sahara protocol driver under drivers/bus/mhi To: Manivannan Sadhasivam , Jeff Hugo Cc: Jonathan Corbet , Shuah Khan , Carl Vanderlip , Oded Gabbay , andersson@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, mhi@lists.linux.dev References: <20260319-sahara_protocol_new_v2-v4-0-47ad79308762@oss.qualcomm.com> <20260319-sahara_protocol_new_v2-v4-2-47ad79308762@oss.qualcomm.com> <0a2af0d1-27da-4f60-952a-409a5abc5647@oss.qualcomm.com> Content-Language: en-US From: Kishore Batta In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Authority-Analysis: v=2.4 cv=C9vZDwP+ c=1 sm=1 tr=0 ts=69de0cbd cx=c_pps a=MTSHoo12Qbhz2p7MsH1ifg==:117 a=fChuTYTh2wq5r3m49p7fHw==:17 a=IkcTkHD0fZMA:10 a=A5OVakUREuEA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=_K5XuSEh1TEqbUxoQ0s3:22 a=W_4NKV7oC5Mk2jKmMQsA:9 a=QEXdDO2ut3YA:10 a=GvdueXVYPmCkWapjIL-Q:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNDE0MDA5MSBTYWx0ZWRfXw5/WTo0dk0CU Ius8D4VZ5lFVmSwfj9A21GUMK+E850ii+6dOSrOh2eipJ3GwzamjF6jg/lIbBrZVNfZoLbR0fPm bW/T+vh5aJDfxyQSEVhmwZwRSGS5nIccYCuf9r4+IOhDRZUKpTnlSQrGZ1k/lVIOc8ASXzOg4Ac JrpQblWQRL1f9UZxBzQsd0a5W4iliW4kyzqq99MFwGUEENrqDf90y0TADjP6z8yvtgFn4Lzdi4W LtifyMBRbnsJM6FIGtMZpOwtPQY+4/vh/GX82zO/15F+EJdvpHNZcrqZrXK5xO6vTQCoothfftf 55j8yBiLYizvKtt0MESirLqXTdGImQQay7jKInXFJAgAjy1HG8hcOb3z1y//XtLmc0wyqO5u9Cl nnY7ClLblcto9GtQdv7a7J4m5Vgk5LRL2TzB6xTFzCENnXSAWU04sYYKDss1EglQfp9xNQKEWEe Rg8v/D0ESnr7oH8D9Qg== X-Proofpoint-GUID: iqOlsgR6mWSpevn_C1wJXmOoy8veqPOM X-Proofpoint-ORIG-GUID: iqOlsgR6mWSpevn_C1wJXmOoy8veqPOM 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=2026-04-14_02,2026-04-13_04,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 suspectscore=0 clxscore=1015 malwarescore=0 lowpriorityscore=0 phishscore=0 bulkscore=0 spamscore=0 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604070000 definitions=main-2604140091 On 4/13/2026 4:34 PM, Manivannan Sadhasivam wrote: > On Thu, Apr 09, 2026 at 02:20:02PM -0600, Jeff Hugo wrote: >> On 3/19/2026 12:31 AM, Kishore Batta wrote: >>> The Sahara protocol driver is currently located under the QAIC >>> accelerator subsystem even though protocol itself is transported over the >>> MHI bus and is used by multiple Qualcomm flashless devices. >>> >>> Relocate the Sahara protocol driver to drivers/bus/mhi and register it as >>> an independent MHI protocol driver. This avoids treating Sahara as QAIC >>> specific and makes it available for reuse by other MHI based devices. >>> >>> As part of this move, introduce a dedicated Kconfig and Makefile under the >>> MHI subsystem and expose the sahara interface via a common header. >> I don't think this belongs under MHI. Mani needs to confirm that he agrees >> with the concept of moving this there. >> >> The Sahara protocol as defined by the spec does not require MHI. We know >> that there are Sahara implementations over USB. I don't see a dependency or >> relationship to MHI other than the current in-kernel implementation uses >> MHI, but there are plenty of things that use MHI (qaic, mhi-net, ath12k, >> etc) which are not a part of the MHI bus. >> > Since Sahara is a MHI client driver, it is OK with me to place it under > drivers/bus/mhi/host/. We do tend to host the client/controller drivers if they > also bind to separate top level subsystems like Net, WWAN... but for the pure > protocol drivers like Sahara, MHI can provide asylum. > > - Mani Thanks for the confirmation Mani. I will keep the Sahara driver under driver/bus/mhi/host/ and also move the Sahara documentation under Documentation/mhi/ directory.