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 Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 627D4C433F5 for ; Sun, 15 May 2022 11:10:45 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id E280E409EF; Sun, 15 May 2022 11:10:44 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id R2BqO_mdX-Tt; Sun, 15 May 2022 11:10:43 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp4.osuosl.org (Postfix) with ESMTPS id 4E56E409EE; Sun, 15 May 2022 11:10:43 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 2FFEFC0039; Sun, 15 May 2022 11:10:43 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id E7CC8C002D for ; Sun, 15 May 2022 11:10:41 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id C756B404F4 for ; Sun, 15 May 2022 11:10:41 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id E2UW34-fQMDN for ; Sun, 15 May 2022 11:10:41 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from soltyk.jannau.net (soltyk.jannau.net [144.76.91.90]) by smtp2.osuosl.org (Postfix) with ESMTPS id F177240112 for ; Sun, 15 May 2022 11:10:40 +0000 (UTC) Received: by soltyk.jannau.net (Postfix, from userid 1000) id E1D0026EA99; Sun, 15 May 2022 13:10:38 +0200 (CEST) Date: Sun, 15 May 2022 13:10:38 +0200 From: Janne Grunau To: Thierry Reding Subject: Re: [PATCH v5 2/5] iommu: Implement of_iommu_get_resv_regions() Message-ID: <20220515111038.GE26732@jannau.net> References: <20220512190052.1152377-1-thierry.reding@gmail.com> <20220512190052.1152377-3-thierry.reding@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220512190052.1152377-3-thierry.reding@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Cc: devicetree@vger.kernel.org, Will Deacon , iommu@lists.linux-foundation.org, Rob Herring , Alyssa Rosenzweig , Dmitry Osipenko , linux-tegra@vger.kernel.org, Robin Murphy , Sameer Pujar , asahi@lists.linux.dev X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 2022-05-12 21:00:49 +0200, Thierry Reding wrote: > From: Thierry Reding > > This is an implementation that IOMMU drivers can use to obtain reserved > memory regions from a device tree node. It uses the reserved-memory DT > bindings to find the regions associated with a given device. If these > regions are marked accordingly, identity mappings will be created for > them in the IOMMU domain that the devices will be attached to. > > Signed-off-by: Thierry Reding > --- > Changes in v5: > - update for new "iommu-addresses" device tree bindings > > Changes in v4: > - fix build failure on !CONFIG_OF_ADDRESS > > Changes in v3: > - change "active" property to identity mapping flag that is part of the > memory region specifier (as defined by #memory-region-cells) to allow > per-reference flags to be used > > Changes in v2: > - use "active" property to determine whether direct mappings are needed > > drivers/iommu/of_iommu.c | 90 ++++++++++++++++++++++++++++++++++++++++ > include/linux/of_iommu.h | 8 ++++ > 2 files changed, 98 insertions(+) > > diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c > index 5696314ae69e..9e341b5e307f 100644 > --- a/drivers/iommu/of_iommu.c > +++ b/drivers/iommu/of_iommu.c > @@ -11,12 +11,15 @@ > #include > #include > #include > +#include > #include > #include > #include > #include > #include > > +#include > + > #define NO_IOMMU 1 > > static int of_iommu_xlate(struct device *dev, > @@ -172,3 +175,90 @@ const struct iommu_ops *of_iommu_configure(struct device *dev, > > return ops; > } > + > +/** > + * of_iommu_get_resv_regions - reserved region driver helper for device tree > + * @dev: device for which to get reserved regions > + * @list: reserved region list > + * > + * IOMMU drivers can use this to implement their .get_resv_regions() callback > + * for memory regions attached to a device tree node. See the reserved-memory > + * device tree bindings on how to use these: > + * > + * Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt > + */ > +void of_iommu_get_resv_regions(struct device *dev, struct list_head *list) > +{ > +#if IS_ENABLED(CONFIG_OF_ADDRESS) > + struct of_phandle_iterator it; > + int err; > + > + of_for_each_phandle(&it, err, dev->of_node, "memory-region", NULL, 0) { > + struct iommu_resv_region *region; > + struct resource res; > + const __be32 *maps; > + int size; Adding 'if (!of_device_is_available(it.node)) continue;' here would help backwards compatibility. My plan was to add the reserved regions with "iommu-addresses" with all zero adresses and sizes with status = "disabled" to the devicetree. A bootloader update is required to fill those. > + > + memset(&res, 0, sizeof(res)); > + > + /* > + * The "reg" property is optional and can be omitted by reserved-memory regions > + * that represent reservations in the IOVA space, which are regions that should > + * not be mapped. > + */ > + if (of_find_property(it.node, "reg", NULL)) { > + err = of_address_to_resource(it.node, 0, &res); > + if (err < 0) { > + dev_err(dev, "failed to parse memory region %pOF: %d\n", > + it.node, err); > + continue; > + } > + } > + > + maps = of_get_property(it.node, "iommu-addresses", &size); > + if (maps) { > + const __be32 *end = maps + size / sizeof(__be32); > + struct device_node *np; > + unsigned int index = 0; > + u32 phandle; > + int na, ns; > + > + while (maps < end) { > + phys_addr_t start, end; > + size_t length; > + > + phandle = be32_to_cpup(maps++); > + np = of_find_node_by_phandle(phandle); > + na = of_n_addr_cells(np); > + ns = of_n_size_cells(np); > + > + start = of_translate_dma_address(np, maps); > + length = of_read_number(maps + na, ns); alternatively we could handle mappings/reservations with length 0 as error and skip them. > + end = start + length - 1; > + > + if (np == dev->of_node) { > + int prot = IOMMU_READ | IOMMU_WRITE; > + enum iommu_resv_type type; > + > + /* > + * IOMMU regions without an associated physical region > + * cannot be mapped and are simply reservations. > + */ > + if (res.end > res.start) > + type = IOMMU_RESV_DIRECT_RELAXABLE; > + else > + type = IOMMU_RESV_RESERVED; > + > + region = iommu_alloc_resv_region(start, length, prot, type); > + if (region) > + list_add_tail(®ion->list, list); > + } > + > + maps += na + ns; > + index++; > + } > + } > + } > +#endif > +} > +EXPORT_SYMBOL(of_iommu_get_resv_regions); > diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h > index 55c1eb300a86..9a5e6b410dd2 100644 > --- a/include/linux/of_iommu.h > +++ b/include/linux/of_iommu.h > @@ -12,6 +12,9 @@ extern const struct iommu_ops *of_iommu_configure(struct device *dev, > struct device_node *master_np, > const u32 *id); > > +extern void of_iommu_get_resv_regions(struct device *dev, > + struct list_head *list); > + > #else > > static inline const struct iommu_ops *of_iommu_configure(struct device *dev, > @@ -21,6 +24,11 @@ static inline const struct iommu_ops *of_iommu_configure(struct device *dev, > return NULL; > } > > +static inline void of_iommu_get_resv_regions(struct device *dev, > + struct list_head *list) > +{ > +} > + > #endif /* CONFIG_OF_IOMMU */ > > #endif /* __OF_IOMMU_H */ > -- > 2.36.1 > Janne _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu