From: Thierry Reding <thierry.reding@gmail.com>
To: Joerg Roedel <joro@8bytes.org>, Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org, Frank Rowand <frowand.list@gmail.com>,
Rob Herring <robh@kernel.org>, Will Deacon <will@kernel.org>,
iommu@lists.linux-foundation.org,
Nicolin Chen <nicolinc@nvidia.com>,
linux-tegra@vger.kernel.org, Dmitry Osipenko <digetx@gmail.com>,
Robin Murphy <robin.murphy@arm.com>
Subject: [PATCH v2 2/5] iommu: Implement of_iommu_get_resv_regions()
Date: Fri, 23 Apr 2021 18:32:31 +0200 [thread overview]
Message-ID: <20210423163234.3651547-3-thierry.reding@gmail.com> (raw)
In-Reply-To: <20210423163234.3651547-1-thierry.reding@gmail.com>
From: Thierry Reding <treding@nvidia.com>
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.
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: devicetree@vger.kernel.org
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
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 | 54 ++++++++++++++++++++++++++++++++++++++++
include/linux/of_iommu.h | 8 ++++++
2 files changed, 62 insertions(+)
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index a9d2df001149..321ebd5fdaba 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -11,12 +11,15 @@
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/of.h>
+#include <linux/of_address.h>
#include <linux/of_iommu.h>
#include <linux/of_pci.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/fsl/mc.h>
+#include <dt-bindings/reserved-memory.h>
+
#define NO_IOMMU 1
/**
@@ -240,3 +243,54 @@ 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)
+{
+ struct of_phandle_iterator it;
+ int err;
+
+ of_for_each_phandle(&it, err, dev->of_node, "memory-region", "#memory-region-cells", 0) {
+ struct iommu_resv_region *region;
+ struct of_phandle_args args;
+ struct resource res;
+
+ args.args_count = of_phandle_iterator_args(&it, args.args, MAX_PHANDLE_ARGS);
+
+ 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;
+ }
+
+ if (args.args_count > 0) {
+ /*
+ * Active memory regions are expected to be accessed by hardware during
+ * boot and must therefore have an identity mapping created prior to the
+ * driver taking control of the hardware. This ensures that non-quiescent
+ * hardware doesn't cause IOMMU faults during boot.
+ */
+ if (args.args[0] & MEMORY_REGION_IDENTITY_MAPPING) {
+ region = iommu_alloc_resv_region(res.start, resource_size(&res),
+ IOMMU_READ | IOMMU_WRITE,
+ IOMMU_RESV_DIRECT_RELAXABLE);
+ if (!region)
+ continue;
+
+ list_add_tail(®ion->list, list);
+ }
+ }
+ }
+}
+EXPORT_SYMBOL(of_iommu_get_resv_regions);
diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h
index 16f4b3e87f20..8412437acaac 100644
--- a/include/linux/of_iommu.h
+++ b/include/linux/of_iommu.h
@@ -16,6 +16,9 @@ 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 int of_get_dma_window(struct device_node *dn, const char *prefix,
@@ -32,6 +35,11 @@ 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 */
--
2.30.2
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-04-23 16:32 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-23 16:32 [PATCH v2 0/5] iommu: Support identity mappings of reserved-memory regions Thierry Reding
2021-04-23 16:32 ` [PATCH v2 1/5] dt-bindings: reserved-memory: Document memory region specifier Thierry Reding
2021-05-20 22:03 ` Rob Herring
2021-05-28 16:54 ` Thierry Reding
2021-06-08 16:51 ` Thierry Reding
2021-07-01 18:14 ` Thierry Reding
2021-07-02 14:16 ` Dmitry Osipenko
2021-09-01 14:13 ` Thierry Reding
2021-09-03 13:20 ` Rob Herring
2021-09-03 13:52 ` Thierry Reding
2021-09-03 14:36 ` Rob Herring
2021-09-03 15:35 ` Thierry Reding
2021-09-07 15:33 ` Rob Herring
2021-09-07 17:44 ` Thierry Reding
2021-09-15 15:19 ` Thierry Reding
2022-02-06 22:27 ` Janne Grunau
2022-02-09 16:31 ` Thierry Reding
2022-02-10 23:15 ` Janne Grunau
2022-03-31 16:25 ` Thierry Reding
2022-04-01 17:08 ` Janne Grunau
2021-04-23 16:32 ` Thierry Reding [this message]
2021-07-02 14:05 ` [PATCH v2 2/5] iommu: Implement of_iommu_get_resv_regions() Dmitry Osipenko
2021-07-16 14:41 ` Rob Herring
2021-07-17 11:07 ` Dmitry Osipenko
2021-07-30 12:18 ` Will Deacon
2021-04-23 16:32 ` [PATCH v2 3/5] iommu: dma: Use of_iommu_get_resv_regions() Thierry Reding
2021-04-23 16:32 ` [PATCH v2 4/5] iommu/tegra-smmu: Add support for reserved regions Thierry Reding
2021-04-23 16:32 ` [PATCH v2 5/5] iommu/tegra-smmu: Support managed domains Thierry Reding
2021-10-11 23:25 ` Dmitry Osipenko
2021-04-24 7:26 ` [PATCH v2 0/5] iommu: Support identity mappings of reserved-memory regions Dmitry Osipenko
2021-04-27 18:30 ` Krishna Reddy
2021-04-28 5:44 ` Dmitry Osipenko
2021-04-29 5:51 ` Krishna Reddy
2021-04-29 12:43 ` Dmitry Osipenko
2021-04-28 5:51 ` Dmitry Osipenko
2021-04-28 5:57 ` Mikko Perttunen
2021-04-28 7:55 ` Dmitry Osipenko
2021-04-28 5:59 ` Dmitry Osipenko
2021-10-03 1:09 ` Dmitry Osipenko
2021-10-04 19:23 ` Thierry Reding
2021-10-04 20:32 ` Dmitry Osipenko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210423163234.3651547-3-thierry.reding@gmail.com \
--to=thierry.reding@gmail.com \
--cc=devicetree@vger.kernel.org \
--cc=digetx@gmail.com \
--cc=frowand.list@gmail.com \
--cc=iommu@lists.linux-foundation.org \
--cc=joro@8bytes.org \
--cc=linux-tegra@vger.kernel.org \
--cc=nicolinc@nvidia.com \
--cc=robh+dt@kernel.org \
--cc=robh@kernel.org \
--cc=robin.murphy@arm.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).