From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 50EC839C63E; Mon, 25 May 2026 20:32:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779741131; cv=none; b=DloYS/3KG5hl13BLHLQX37gwO8ppMIBfl06WUFk10ClyudSc804XKpSa8MstzRHKwXuLAe5DiRFan6utsYdCFtJ+BqeSiDEIGV+8XrxMRdmfpsr6KcQxlVpFcqpif3j2iD9VvLKDK0rIoI6zQMo431uWNvdUPjus1Yxbh+eKFCc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779741131; c=relaxed/simple; bh=h3kNNf9bQmpIEMHsGOEF4OitjEbuQUeFi9LDNYzBmc4=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=nzfyQqddWShi0Ds/Y0Rby2pRA1kIOgu9BBt+54OqEkgXKwI4YuDJts3KVyLr/5/EKZqWQ7Xd7UpsKmKybUJcf7ZQIWLxA7TKWvdgiKMoIVlM2w9Zolc7kXs7Sm4n0PleqIykSvOGTJ4o9Zj7abYE3DhBrzGhMXLUK7A2aYswPgw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OQXg9+0g; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OQXg9+0g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 339801F00A3A; Mon, 25 May 2026 20:32:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779741130; bh=h3kNNf9bQmpIEMHsGOEF4OitjEbuQUeFi9LDNYzBmc4=; h=Date:From:To:CC:Subject:In-Reply-To:References; b=OQXg9+0gBgVvIfqDGCcwOipVvzHltjs1bqpls3vPAz8N44CvRFNDtNwIu9hXODWgr k7vkypfYfp0ftClTxflM7Xl3RmPknAACAwXkRPXpzN9hgYQ9XWWxo8GkTQI3lvu76D kB4K7UxIvXuEAMZc0hC7zird+pw4vlZ92t9txln80Wi5NfjXZh6Edg34Z7QDv+Gh/r Ro+97wk90VkdyixHl01L4LGYTuErJXaBbJJ1Du0NJCseYZ8qu0gukwI0/79VdCUkm3 TD0oWz8vnd7XC4N7wX8xDwuClwCG/2aNISAwHgz/P9BIuPI4khVX9nEWhxuWDStH7S R3DCHRFBh0rgA== Date: Mon, 25 May 2026 22:32:06 +0200 From: Niklas Cassel To: Koichiro Den CC: Manivannan Sadhasivam , Frank Li , =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , Kishon Vijay Abraham I , Bjorn Helgaas , Jonathan Corbet , Shuah Khan , Vinod Koul , Arnd Bergmann , Damien Le Moal , Marek Vasut , Yoshihiro Shimoda , linux-pci@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org Subject: =?US-ASCII?Q?Re=3A_=5BPATCH_v2_0/3=5D_PCI=3A_endpoint=3A_Add?= =?US-ASCII?Q?_PCI_DMA_endpoint_function_=28part_3/3=29?= User-Agent: Thunderbird for Android In-Reply-To: <3dkicfydmrlm2i6ks34kwjdmlvb22ryftkfw2yj62o4rtj5xvl@f4gby5vlwtdf> References: <20260525063456.3317509-1-den@valinux.co.jp> <3dkicfydmrlm2i6ks34kwjdmlvb22ryftkfw2yj62o4rtj5xvl@f4gby5vlwtdf> Message-ID: Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 25 May 2026 16:03:35 CEST, Koichiro Den wrote: >On Mon, May 25, 2026 at 10:35:46AM +0200, Niklas Cassel wrote: >> On Mon, May 25, 2026 at 04:05:02PM +0900, Koichiro Den wrote: >>=20 >> If so, but do really all endpoint controllers / endpoint controller dri= vers >> support binding to multiple EPFs? > >No=2E For example, R-Car S4's PCIe controller supports multi-functions, w= hile >RK3588's PCIe controller seems not=2E So with this scheme, RK3588 would n= ot >support the NTB transport backed by PCI EP DMA=2E I guess it depends on 'max-functions' being set in device tree or not: https://github=2Ecom/torvalds/linux/blob/master/drivers/pci/controller/dwc= /pcie-designware-ep=2Ec#L1365-L1367 AFAICT, this value depends on how the DWC PCI controller hardware configur= ation=2E > >That restriction should be documented with the new NTB transport, which I= will >submit if the direction taken by this series is acceptable=2E This is easy for me to say, since I am not the NTB maintainer, but it woul= d be nice if we could somehow come up with a design where we don't only sup= port EPCs that have 'max-functions' !=3D 1, because IIRC, most PCI EPCs hav= e 'max-functions' =3D=3D 1=2E Kind regards, Nikla