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 45F279443; Fri, 27 Sep 2024 23:51:19 +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=1727481080; cv=none; b=MWqTYl6tPpNTAjE6ADC4ePU8j7up3B7891PzsO8TJT8brV3BnB46ED2Op+2IYpDIIuKwGRUzE/efONh6cdLjPmdVbgpD4ah8AEQ8s7SSScUW3qj7buN1EVpQ0ewU4MTe8dfeVU1oKVwQw6dTtSOYcUficBMYx3kPJ/mjFOfDzm4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727481080; c=relaxed/simple; bh=ewY/sv1t7nj53njmVivVzd//BFGp3FOUKqt7Okgo7NI=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=dGCq6Kt/tbc4JkR0/LN46Q74oDQEvbUgDpFObNfXOMBEMZEXtLaSLz44+ljk8BvIBZkvkEJl2M2btMFSfP4766ETLjWmpoQcwbwPFcYgmQK7PfOxt6wHDknz2lr91hpPoYe8isqCJqwdW2jtzBQi2i9PIZut9/Ty9tvQTtFlzQA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YrYKABT6; 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="YrYKABT6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7AC6FC4CEC6; Fri, 27 Sep 2024 23:51:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727481079; bh=ewY/sv1t7nj53njmVivVzd//BFGp3FOUKqt7Okgo7NI=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=YrYKABT6UQnYignz9+180E4GcxNgMeqQQyEgAHmmbf7Bh897jAsp8D8U1v1pYffw9 IZ4lRZ2CJyVCSo5WQh3gU6/AGXEEOpZqTTCi7ObWJYdcTqBwL8qD1wRV0f7qh4UGlb EE2TufiS4ABxVmTIQOGY93zl7Mj6eP9O2LL/C1bOos31Fn/K8MgoYrC1G68KyAsi4P N1UbrNlDlEdnf9jAQ738cJGWW0HRi8bIKBWp2hhxeR1sg62oXg8UF+qoP9eWhg4QMD 9sADzU5wBKz+MnpBvlaY/39tSvOAol46oIGrtTbjdFKleKOI1Ru8+Px7KgzcCsW+EZ QbEDrCh+r13vg== Date: Fri, 27 Sep 2024 18:51:17 -0500 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 v2 1/3] of: address: Add cpu_untranslate_addr to struct of_pci_range Message-ID: <20240927235117.GA98484@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: <20240926-pci_fixup_addr-v2-1-e4524541edf4@nxp.com> On Thu, Sep 26, 2024 at 12:47:13PM -0400, Frank Li wrote: > Introduce field 'cpu_untranslate_addr' in of_pci_range to retrieve > untranslated CPU address information. This is required for hardware like > i.MX8QXP to configure the PCIe controller ATU and eliminate the need for > workaround address fixups in drivers. Currently, many drivers use > hardcoded CPU addresses for fixups, but this information is already > described in the Device Tree. With correct hardware descriptions, such > fixups can be removed. Instead of saying "required for hardware like i.MX8QXP", can we say something specific about what this kind of hardware *does* that requires this? I *think* the point is that there's some address translation being done between the primary and secondary sides of some bridge. I think "many drivers use hardcoded CPU addresses for fixups" basically means the .cpu_addr_fixup() callback hardcodes that translation in the code, e.g., "cpu_addr & CDNS_PLAT_CPU_TO_BUS_ADDR", "cpu_addr + BUS_IATU_OFFSET", etc, even though those translations *should* be described via DT. > ┌─────────┐ ┌────────────┐ > ┌─────┐ │ │ IA: 0x8ff0_0000 │ │ > │ CPU ├───►│ BUS ├─────────────────┐ │ PCI │ > └─────┘ │ │ IA: 0x8ff8_0000 │ │ │ > CPU Addr │ Fabric ├─────────────┐ │ │ Controller │ > 0x7000_0000 │ │ │ │ │ │ > │ │ │ │ │ │ PCI Addr > │ │ │ └──► CfgSpace ─┼────────────► > │ ├─────────┐ │ │ │ 0 > │ │ │ │ │ │ > └─────────┘ │ └──────► IOSpace ─┼────────────► > │ │ │ 0 > │ │ │ > └──────────► MemSpace ─┼────────────► > IA: 0x8000_0000 │ │ 0x8000_0000 > └────────────┘ What does "IA" stand for? I don't quite understand the mapping done by the "BUS Fabric" block. It looks like you're saying the CPU Addr 0x7000_0000 is translated to all three of IA 0x8ff0_0000, IA 0x8ff8_0000, and IA 0x8000_0000, but that doesn't seem right. > bus@5f000000 { > compatible = "simple-bus"; > #address-cells = <1>; > #size-cells = <1>; > ranges = <0x5f000000 0x0 0x5f000000 0x21000000>, > <0x80000000 0x0 0x70000000 0x10000000>; > > pcieb: pcie@5f010000 { > compatible = "fsl,imx8q-pcie"; > reg = <0x5f010000 0x10000>, <0x8ff00000 0x80000>; > reg-names = "dbi", "config"; > #address-cells = <3>; > #size-cells = <2>; > device_type = "pci"; > bus-range = <0x00 0xff>; > ranges = <0x81000000 0 0x00000000 0x8ff80000 0 0x00010000>, > <0x82000000 0 0x80000000 0x80000000 0 0x0ff00000>; > ... > }; > }; > > 'cpu_untranslate_addr' in of_pci_range can indicate above diagram IA > address information. > > Signed-off-by: Frank Li > --- > Change from v1 to v2 > - add cpu_untranslate_addr in of_pci_range, instead adding new API. > --- > drivers/of/address.c | 2 ++ > include/linux/of_address.h | 1 + > 2 files changed, 3 insertions(+) > > diff --git a/drivers/of/address.c b/drivers/of/address.c > index 286f0c161e332..f4cb82f5313cf 100644 > --- a/drivers/of/address.c > +++ b/drivers/of/address.c > @@ -811,6 +811,8 @@ struct of_pci_range *of_pci_range_parser_one(struct of_pci_range_parser *parser, > else > range->cpu_addr = of_translate_address(parser->node, > parser->range + na); > + > + range->cpu_untranslate_addr = of_read_number(parser->range + na, parser->pna); > range->size = of_read_number(parser->range + parser->pna + na, ns); > > parser->range += np; > diff --git a/include/linux/of_address.h b/include/linux/of_address.h > index 26a19daf0d092..0683ce0c07f68 100644 > --- a/include/linux/of_address.h > +++ b/include/linux/of_address.h > @@ -26,6 +26,7 @@ struct of_pci_range { > u64 bus_addr; > }; > u64 cpu_addr; > + u64 cpu_untranslate_addr; > u64 size; > u32 flags; > }; > > -- > 2.34.1 >