From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 90A1C1D7E54; Thu, 16 Jan 2025 22:49:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737067744; cv=none; b=eAW2wBKQGE4i0T9Ph+5SwwGnKRI5mRLhpNyp7lwnQMP2IenKdqYI98YgnVUU326XfuOEo9YRlUAYA0jmBYNQuk5l/tNC9P67y4QH8GbPk8lwnjMAYym1eZlprdnSNuyNEx8Hg7uloLbSy7+bvbAJ3p2eByfIram8tRprGil1H8g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737067744; c=relaxed/simple; bh=5aThHilBPblCgfz/BgJ0mgjfS1hGQLJWECyx+bt7Wt0=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=h4mrVO8gGyxzIQm6ac8BX6tQgQ4gk2AeVnDGLPOg6G++t3ZWtoauCAquNULUcPdKoHH+JfZAREALGRTv7UXNImyTZzAqc9Y/LDnQxX1/Bw2YEEUoxAZ5wKI0GqZRsw+mJtT2T6C+qVxMeIkbSWJN61tF1S/28msqK8+MAZ3SgSQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=szH71zQE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="szH71zQE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0CD02C4CED6; Thu, 16 Jan 2025 22:49:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737067744; bh=5aThHilBPblCgfz/BgJ0mgjfS1hGQLJWECyx+bt7Wt0=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=szH71zQEi99amVjmugt5JvwXVGZ+pHOC18l1Q3auVKFW/ZAPJDY42oap4KZ82aiY+ gjkfq/RF3lhECK8PSywzROXubYGQyzvw2tUXdzMc3GyHx18tWlc6MoSyxouoCuqslY F6wK7L7kbao7cwJg09R+JlwmmSVBswp8QDIL8JZRybxm62s5l+ZC1Iw5hll5y86Gtm HWoIoBjPagiX5tawGzfr3aQzJbXl94B6fySIbLUIIVcez2xiSB0ktxVQ5Pg2yqbpbx wXT/lV/5PjfbUkAIYeSiogqzX03X6RU14RyyGGA9soRDPKqUTTTi711X6fAtnCf0Zt c9FqqjDAf48AA== Date: Thu, 16 Jan 2025 16:49:02 -0600 From: Bjorn Helgaas To: Frank Li Cc: Rob Herring , Saravana Kannan , Jingoo Han , Manivannan Sadhasivam , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Bjorn Helgaas , Richard Zhu , Lucas Stach , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, imx@lists.linux.dev Subject: Re: [PATCH v8 3/7] PCI: dwc: ep: Add bus_addr_base for outbound window Message-ID: <20250116224902.GA614046@bhelgaas> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Jan 16, 2025 at 03:02:44PM -0500, Frank Li wrote: > On Thu, Jan 16, 2025 at 01:45:58PM -0600, Bjorn Helgaas wrote: > > On Thu, Jan 16, 2025 at 01:04:16PM -0500, Frank Li wrote: > > > On Thu, Jan 16, 2025 at 09:32:39AM -0600, Bjorn Helgaas wrote: > > > > On Tue, Nov 19, 2024 at 02:44:21PM -0500, Frank Li wrote: > > > > > Endpoint > > > > > ┌───────────────────────────────────────────────┐ > > > > > │ pcie-ep@5f010000 │ > > > > > │ ┌────────────────┐│ > > > > > │ │ Endpoint ││ > > > > > │ │ PCIe ││ > > > > > │ │ Controller ││ > > > > > │ bus@5f000000 │ ││ > > > > > │ ┌──────────┐ │ ││ > > > > > │ │ │ Outbound Transfer ││ > > > > > │┌─────┐ │ Bus ┼─────►│ ATU ──────────┬┬─────► > > > > > ││ │ │ Fabric │Bus │ ││PCI Addr > > > > > ││ CPU ├───►│ │Addr │ ││0xA000_0000 > > > > > ││ │CPU │ │0x8000_0000 ││ > > > > > │└─────┘Addr└──────────┘ │ ││ > > > > > │ 0x7000_0000 └────────────────┘│ > > > > > └───────────────────────────────────────────────┘ > > > > > > > > > > Use 'ranges' property in DT to configure the iATU outbound window address. > > > > > The bus fabric generally passes the same address to the PCIe EP controller, > > > > > but some bus fabrics map the address before sending it to the PCIe EP > > > > > controller. > > > > > > > > > > Above diagram, CPU write data to outbound windows address 0x7000_0000, Bus > > > > > fabric map it to 0x8000_0000. ATU should use bus address 0x8000_0000 as > > > > > input address and map to PCI address 0xA000_0000. > > > > > > > > > > Previously, 'cpu_addr_fixup()' was used to handle address conversion. Now, > > > > > the device tree provides this information, preferring a common method. > > > > > > > > > > bus@5f000000 { > > > > > compatible = "simple-bus"; > > > > > ranges = <0x80000000 0x0 0x70000000 0x10000000>; > > > > > > > > > > pcie-ep@5f010000 { > > > > > reg = <0x80000000 0x10000000>; > > > > > reg-names ="addr_space"; > > > > > ... > > > > > }; > > > > > ... > > > > > }; > > > > > > > > > > 'ranges' in bus@5f000000 descript how address map from CPU address to bus > > > > > address. > > > > > > > > Shouldn't there also be a pcie-ep@5f010000 'ranges' property to > > > > describe the translation for the window from bus addr 0x8000_0000 to > > > > PCI addr 0xA000_0000? > > > > > > Needn't 'ranges' under pcie-ep@5f010000 because history reason. DWC use > > > reg-names "addr_space" descript outbound windows space. > > > > If reg-name "addr_space" is used instead of 'ranges' for some > > historical reason, we should mention that in the commit log so people > > don't assume that this difference is the way it's *supposed* to be > > done. > > How about add comments after > > reg-names ="addr_space"; // Indicate EP outbound windows space instead use > ranges by histortical reason. OK, that seems reasonable. Where does the 0xA000_0000 PCI address come from? I assume that's in DT somewhere too? Is there a binding in the tree that would take advantage of this patch that I can look at? arch/arm64/boot/dts/freescale/imx8-ss-hsio.dtsi has bus@5f000000 that does this translation, but I don't see any endpoint mode that uses it. > > > All regs need call of_property_read_reg() to get untranslated address. > > > ranges: use "parent_bus_addr" in [1]. > > > > I think we should at least use the same name ("parent_bus_addr", not > > "bus_addr_base") and probably also figure out a wrapper or similar way > > to use 'ranges' for future endpoint drivers and fall back to > > "addr_space" for DWC. > > Okay for name parent_bus_addr. > Do you need me to respin it? Or you change it by yourself? I can do that. Bjorn > > > > [1] https://lore.kernel.org/r/20241119-pci_fixup_addr-v8-1-c4bfa5193288@nxp.com