From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FAKE_REPLY_C,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41818C32792 for ; Mon, 30 Sep 2019 21:40:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 086A62190F for ; Mon, 30 Sep 2019 21:40:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569879651; bh=s26f+4Qrh8dEz5mtj+K68gZUPj8yMT5f75zQIdkTK9k=; h=Date:From:To:Cc:Subject:In-Reply-To:List-ID:From; b=fldnjKfgccLjv0OzkUubRJxnig3tPqMioGcJ1eQv+4e47xQMlNAEnwsZMqpk7Vsuw fN6LatNbJ9Xzn1ChhSIJK2f7vIeFP6em8o3ZHkkPtBQE5hFHTdnFEZIavBTHtQ1nuy qNbgOGXTey+S6Wv1MTg0LELIhbsAFhD4OZImrQFk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726314AbfI3Vku (ORCPT ); Mon, 30 Sep 2019 17:40:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:53584 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731036AbfI3Vku (ORCPT ); Mon, 30 Sep 2019 17:40:50 -0400 Received: from localhost (unknown [69.71.4.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 208D720815; Mon, 30 Sep 2019 21:40:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569879649; bh=s26f+4Qrh8dEz5mtj+K68gZUPj8yMT5f75zQIdkTK9k=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=vhQ02bfNHRsNR5IftQPMp2GRllZIMFl/wC8F6tpAOMMYTPagJkaVmrLb64NYZUYj8 kdQuNOExxiO36eIv3FzjzfiVgwdCAl3mTjR8voUK/do+0gCDIOFMs1BACnfBIxS3Y3 r5QHkRM2lo0zJaFZPlIQ1Zg4yfMiBBMI1NpO+bIg= Date: Mon, 30 Sep 2019 16:40:46 -0500 From: Bjorn Helgaas To: marek.vasut@gmail.com Cc: linux-pci@vger.kernel.org, Oza Pawandeep , Marek Vasut , Arnd Bergmann , Geert Uytterhoeven , Lorenzo Pieralisi , Robin Murphy , Simon Horman , Wolfram Sang , linux-renesas-soc@vger.kernel.org Subject: Re: [PATCH 1/2] OF/PCI: Export inbound memory interface to PCI RC drivers. Message-ID: <20190930214046.GA201622@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190809173449.20126-1-marek.vasut@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org This would follow the convention for subject lines: PCI: OF: Add of_pci_get_dma_ranges() for inbound DMA restrictions On Fri, Aug 09, 2019 at 07:34:48PM +0200, marek.vasut@gmail.com wrote: > From: Oza Pawandeep > > The patch exports interface to PCIe RC drivers so that, > Drivers can get their inbound memory configuration. IIUC this interface (of_pci_get_dma_ranges()) is not used directly by *drivers*; it is used by of_bus_pci_get_dma_ranges() in the next patch, and it's called by the driver core via this path: really_probe pci_dma_configure # pci_bus_type.dma_configure of_dma_configure of_dma_get_range bus->get_dma_ranges of_bus_pci_get_dma_ranges # of_busses[0].get_dma_ranges of_pci_get_dma_ranges > It provides basis for IOVA reservations for inbound memory > holes, if RC is not capable of addressing all the host memory, > Specifically when IOMMU is enabled and on ARMv8 where 64bit IOVA > could be allocated. > > It handles multiple inbound windows, and returns resources, > and is left to the caller, how it wants to use them. This should say exactly what the problem is, maybe even with a link to a problem report. I assume it is something like "RC cannot address all of host memory, and if we happen to allocate a buffer that's not addressable, DMA to the buffer fails". It'd be nice to know what the failure looks like (SERR# asserted, panic, reboot, etc). > Signed-off-by: Oza Pawandeep > Signed-off-by: Marek Vasut > Cc: Arnd Bergmann > Cc: Geert Uytterhoeven > Cc: Lorenzo Pieralisi > Cc: Robin Murphy > Cc: Simon Horman > Cc: Wolfram Sang > Cc: linux-renesas-soc@vger.kernel.org > To: linux-pci@vger.kernel.org > --- > drivers/pci/of.c | 96 ++++++++++++++++++++++++++++++++++++++++++ > include/linux/of_pci.h | 7 +++ > 2 files changed, 103 insertions(+) > > diff --git a/drivers/pci/of.c b/drivers/pci/of.c > index bc7b27a28795..4018f1a26f6f 100644 > --- a/drivers/pci/of.c > +++ b/drivers/pci/of.c > @@ -347,6 +347,102 @@ int devm_of_pci_get_host_bridge_resources(struct device *dev, > return err; > } > EXPORT_SYMBOL_GPL(devm_of_pci_get_host_bridge_resources); > + > +/** > + * of_pci_get_dma_ranges - Parse PCI host bridge inbound resources from DT > + * @np: device node of the host bridge having the dma-ranges property > + * @resources: list where the range of resources will be added after DT parsing > + * > + * It is the caller's job to free the @resources list. > + * > + * This function will parse the "dma-ranges" property of a > + * PCI host bridge device node and setup the resource mapping based > + * on its content. Rewrap this so it uses the whole width (75-78 columns). > + * It returns zero if the range parsing has been successful or a standard error > + * value if it failed. > + */ > + > +int of_pci_get_dma_ranges(struct device_node *dn, struct list_head *resources) > +{ > + struct device_node *node = of_node_get(dn); > + int rlen; > + int pna = of_n_addr_cells(node); > + const int na = 3, ns = 2; > + int np = pna + na + ns; > + int ret = 0; > + struct resource *res; > + const u32 *dma_ranges; > + struct of_pci_range range; > + > + if (!node) > + return -EINVAL; > + > + while (1) { > + dma_ranges = of_get_property(node, "dma-ranges", &rlen); > + > + /* Ignore empty ranges, they imply no translation required. */ > + if (dma_ranges && rlen > 0) > + break; > + > + /* no dma-ranges, they imply no translation required. */ Capitalize as you do other comments (s/no/No/). > + if (!dma_ranges) > + break; > + > + node = of_get_next_parent(node); > + > + if (!node) > + break; > + } > + > + if (!dma_ranges) { > + pr_debug("pcie device has no dma-ranges defined for node(%s)\n", This isn't PCIe-specific, so it should say "PCI". > + dn->full_name); > + ret = -EINVAL; > + goto out; > + } > + > + while ((rlen -= np * 4) >= 0) { > + range.pci_space = be32_to_cpup((const __be32 *) &dma_ranges[0]); > + range.pci_addr = of_read_number(dma_ranges + 1, ns); > + range.cpu_addr = of_translate_dma_address(node, > + dma_ranges + na); > + range.size = of_read_number(dma_ranges + pna + na, ns); > + range.flags = IORESOURCE_MEM; > + > + dma_ranges += np; > + > + /* > + * If we failed translation or got a zero-sized region > + * then skip this range. > + */ > + if (range.cpu_addr == OF_BAD_ADDR || range.size == 0) > + continue; > + > + res = kzalloc(sizeof(struct resource), GFP_KERNEL); > + if (!res) { > + ret = -ENOMEM; > + goto parse_failed; > + } > + > + ret = of_pci_range_to_resource(&range, dn, res); > + if (ret) { > + kfree(res); > + continue; > + } > + > + pci_add_resource_offset(resources, res, > + res->start - range.pci_addr); > + } > + return ret; > + > +parse_failed: > + pci_free_resource_list(resources); > +out: > + of_node_put(node); > + return ret; > +} > +EXPORT_SYMBOL_GPL(of_pci_get_dma_ranges); I don't think this needs to be exported, does it? The only caller I see (of_bus_pci_get_dma_ranges()) cannot be in a module. > #endif /* CONFIG_OF_ADDRESS */ > > #if IS_ENABLED(CONFIG_OF_IRQ) > diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h > index 21a89c4880fa..02bff0587dd2 100644 > --- a/include/linux/of_pci.h > +++ b/include/linux/of_pci.h > @@ -13,6 +13,7 @@ struct device_node; > struct device_node *of_pci_find_child_device(struct device_node *parent, > unsigned int devfn); > int of_pci_get_devfn(struct device_node *np); > +int of_pci_get_dma_ranges(struct device_node *np, struct list_head *resources); > void of_pci_check_probe_only(void); > #else > static inline struct device_node *of_pci_find_child_device(struct device_node *parent, > @@ -26,6 +27,12 @@ static inline int of_pci_get_devfn(struct device_node *np) > return -EINVAL; > } > > +static inline int of_pci_get_dma_ranges(struct device_node *np, > + struct list_head *resources) > +{ > + return -EINVAL; > +} > + > static inline void of_pci_check_probe_only(void) { } > #endif > > -- > 2.20.1 >