From: Sricharan R <sricharan@codeaurora.org>
To: robin.murphy@arm.com, will.deacon@arm.com, joro@8bytes.org,
lorenzo.pieralisi@arm.com, iommu@lists.linux-foundation.org,
linux-arm-kernel@lists.infradead.org,
linux-arm-msm@vger.kernel.org, m.szyprowski@samsung.com,
bhelgaas@google.com, linux-pci@vger.kernel.org,
linux-acpi@vger.kernel.org, tn@semihalf.com,
hanjun.guo@linaro.org, okaya@codeaurora.org
Cc: sricharan@codeaurora.org
Subject: [PATCH V8 02/11] iommu/of: Prepare for deferred IOMMU configuration
Date: Fri, 3 Feb 2017 21:18:44 +0530 [thread overview]
Message-ID: <1486136933-20328-3-git-send-email-sricharan@codeaurora.org> (raw)
In-Reply-To: <1486136933-20328-1-git-send-email-sricharan@codeaurora.org>
From: Robin Murphy <robin.murphy@arm.com>
IOMMU configuration represents unchanging properties of the hardware,
and as such should only need happen once in a device's lifetime, but
the necessary interaction with the IOMMU device and driver complicates
exactly when that point should be.
Since the only reasonable tool available for handling the inter-device
dependency is probe deferral, we need to prepare of_iommu_configure()
to run later than it is currently called (i.e. at driver probe rather
than device creation), to handle being retried, and to tell whether a
not-yet present IOMMU should be waited for or skipped (by virtue of
having declared a built-in driver or not).
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
drivers/iommu/of_iommu.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 42 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index ee49081..1f92d98 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -96,6 +96,19 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
}
EXPORT_SYMBOL_GPL(of_get_dma_window);
+static bool of_iommu_driver_present(struct device_node *np)
+{
+ /*
+ * If the IOMMU still isn't ready by the time we reach init, assume
+ * it never will be. We don't want to defer indefinitely, nor attempt
+ * to dereference __iommu_of_table after it's been freed.
+ */
+ if (system_state > SYSTEM_BOOTING)
+ return false;
+
+ return of_match_node(&__iommu_of_table, np);
+}
+
static const struct iommu_ops
*of_iommu_xlate(struct device *dev, struct of_phandle_args *iommu_spec)
{
@@ -104,12 +117,20 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
int err;
ops = iommu_get_instance(fwnode);
- if (!ops || !ops->of_xlate)
+ if ((ops && !ops->of_xlate) ||
+ (!ops && !of_iommu_driver_present(iommu_spec->np)))
return NULL;
err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
if (err)
return ERR_PTR(err);
+ /*
+ * The otherwise-empty fwspec handily serves to indicate the specific
+ * IOMMU device we're waiting for, which will be useful if we ever get
+ * a proper probe-ordering dependency mechanism in future.
+ */
+ if (!ops)
+ return ERR_PTR(-EPROBE_DEFER);
err = ops->of_xlate(dev, iommu_spec);
if (err)
@@ -186,14 +207,34 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
struct device_node *master_np)
{
const struct iommu_ops *ops;
+ struct iommu_fwspec *fwspec = dev->iommu_fwspec;
if (!master_np)
return NULL;
+ if (fwspec) {
+ if (fwspec->ops)
+ return fwspec->ops;
+
+ /* In the deferred case, start again from scratch */
+ iommu_fwspec_free(dev);
+ }
+
if (dev_is_pci(dev))
ops = of_pci_iommu_init(to_pci_dev(dev), master_np);
else
ops = of_platform_iommu_init(dev, master_np);
+ /*
+ * If we have reason to believe the IOMMU driver missed the initial
+ * add_device callback for dev, replay it to get things in order.
+ */
+ if (!IS_ERR_OR_NULL(ops) && ops->add_device &&
+ dev->bus && !dev->iommu_group) {
+ int err = ops->add_device(dev);
+
+ if (err)
+ ops = ERR_PTR(err);
+ }
return IS_ERR(ops) ? NULL : ops;
}
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
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next prev parent reply other threads:[~2017-02-03 15:48 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-03 15:48 [PATCH V8 00/11] IOMMU probe deferral support Sricharan R
2017-02-03 15:48 ` [PATCH V8 01/11] iommu/of: Refactor of_iommu_configure() for error handling Sricharan R
2017-03-08 18:58 ` Jean-Philippe Brucker
2017-03-08 19:28 ` Robin Murphy
2017-03-09 9:52 ` sricharan
2017-03-09 11:21 ` Robin Murphy
2017-02-03 15:48 ` Sricharan R [this message]
2017-02-03 15:48 ` [PATCH V8 03/11] of: dma: Move range size workaround to of_dma_get_range() Sricharan R
2017-02-03 15:48 ` [PATCH V8 04/11] of: dma: Make of_dma_deconfigure() public Sricharan R
2017-02-03 15:48 ` [PATCH V8 05/11] ACPI/IORT: Add function to check SMMUs drivers presence Sricharan R
2017-02-03 15:48 ` [PATCH V8 06/11] of/acpi: Configure dma operations at probe time for platform/amba/pci bus devices Sricharan R
2017-02-03 15:48 ` [PATCH V8 07/11] iommu: of: Handle IOMMU lookup failure with deferred probing or error Sricharan R
2017-05-02 18:35 ` Geert Uytterhoeven
2017-05-03 9:54 ` Robin Murphy
2017-05-03 10:24 ` Sricharan R
2017-05-03 11:13 ` Sricharan R
2017-05-05 13:23 ` Geert Uytterhoeven
2017-05-17 9:22 ` Magnus Damm
2017-05-17 10:28 ` Sricharan R
2017-05-15 14:22 ` Will Deacon
2017-05-16 2:26 ` sricharan
2017-05-15 20:37 ` Laurent Pinchart
2017-05-15 21:34 ` Laurent Pinchart
2017-05-16 2:23 ` sricharan
2017-05-16 7:17 ` Laurent Pinchart
2017-05-16 9:47 ` Sakari Ailus
2017-05-16 13:40 ` sricharan
2017-05-16 14:06 ` Laurent Pinchart
2017-05-16 14:04 ` Robin Murphy
2017-05-16 14:10 ` Laurent Pinchart
2017-05-16 14:29 ` sricharan
2017-05-16 14:46 ` Laurent Pinchart
2017-05-16 14:52 ` Robin Murphy
2017-02-03 15:48 ` [PATCH V8 08/11] drivers: acpi: " Sricharan R
2017-02-03 16:15 ` Sricharan
2017-02-03 17:39 ` Robin Murphy
2017-02-05 6:51 ` Sricharan
2017-02-03 15:48 ` [PATCH V8 09/11] arm64: dma-mapping: Remove the notifier trick to handle early setting of dma_ops Sricharan R
2017-02-03 15:48 ` [PATCH V8 10/11] iommu/arm-smmu: Clean up early-probing workarounds Sricharan R
2017-02-03 15:48 ` [PATCH V8 11/11] ACPI/IORT: Remove linker section for IORT entries probing Sricharan R
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