[PATCH 7/7] iommu/arm-smmu: Allow building as a module
Will Deacon
will at kernel.org
Wed Oct 30 14:51:12 UTC 2019
By conditionally dropping support for the legacy binding and exporting
the newly introduced 'arm_smmu_impl_init()' function we can allow the
ARM SMMU driver to be built as a module.
Signed-off-by: Will Deacon <will at kernel.org>
---
drivers/iommu/Kconfig | 14 ++++++++-
drivers/iommu/arm-smmu-impl.c | 6 ++++
drivers/iommu/arm-smmu.c | 54 +++++++++++++++++++++--------------
3 files changed, 51 insertions(+), 23 deletions(-)
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 7583d47fc4d5..02703f51e533 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -350,7 +350,7 @@ config SPAPR_TCE_IOMMU
# ARM IOMMU support
config ARM_SMMU
- bool "ARM Ltd. System MMU (SMMU) Support"
+ tristate "ARM Ltd. System MMU (SMMU) Support"
depends on (ARM64 || ARM) && MMU
select IOMMU_API
select IOMMU_IO_PGTABLE_LPAE
@@ -362,6 +362,18 @@ config ARM_SMMU
Say Y here if your SoC includes an IOMMU device implementing
the ARM SMMU architecture.
+config ARM_SMMU_LEGACY_DT_BINDINGS
+ bool "Support the legacy \"mmu-masters\" devicetree bindings"
+ depends on ARM_SMMU=y && OF
+ help
+ Support for the badly designed and deprecated \"mmu-masters\"
+ devicetree bindings. This allows some DMA masters to attach
+ to the SMMU but does not provide any support via the DMA API.
+ If you're lucky, you might be able to get VFIO up and running.
+
+ If you say Y here then you'll make me very sad. Instead, say N
+ and move your firmware to the utopian future that was 2016.
+
config ARM_SMMU_DISABLE_BYPASS_BY_DEFAULT
bool "Default to disabling bypass on ARM SMMU v1 and v2"
depends on ARM_SMMU
diff --git a/drivers/iommu/arm-smmu-impl.c b/drivers/iommu/arm-smmu-impl.c
index 5c87a38620c4..2f82d40317d6 100644
--- a/drivers/iommu/arm-smmu-impl.c
+++ b/drivers/iommu/arm-smmu-impl.c
@@ -5,6 +5,7 @@
#define pr_fmt(fmt) "arm-smmu: " fmt
#include <linux/bitfield.h>
+#include <linux/module.h>
#include <linux/of.h>
#include "arm-smmu.h"
@@ -172,3 +173,8 @@ struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu)
return smmu;
}
+EXPORT_SYMBOL_GPL(arm_smmu_impl_init);
+
+MODULE_DESCRIPTION("IOMMU quirks for ARM architected SMMU implementations");
+MODULE_AUTHOR("Robin Murphy <robin.murphy at arm.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 53bbe0663b9e..9ef14830546d 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -125,6 +125,12 @@ static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
return container_of(dom, struct arm_smmu_domain, domain);
}
+static struct platform_driver arm_smmu_driver;
+static struct iommu_ops arm_smmu_ops;
+
+#ifdef CONFIG_ARM_SMMU_LEGACY_DT_BINDINGS
+static void arm_smmu_bus_init(void);
+
static struct device_node *dev_get_dev_node(struct device *dev)
{
if (dev_is_pci(dev)) {
@@ -160,9 +166,6 @@ static int __find_legacy_master_phandle(struct device *dev, void *data)
return err == -ENOENT ? 0 : err;
}
-static struct platform_driver arm_smmu_driver;
-static struct iommu_ops arm_smmu_ops;
-
static int arm_smmu_register_legacy_master(struct device *dev,
struct arm_smmu_device **smmu)
{
@@ -214,6 +217,27 @@ static int arm_smmu_register_legacy_master(struct device *dev,
return err;
}
+/*
+ * With the legacy DT binding in play, we have no guarantees about
+ * probe order, but then we're also not doing default domains, so we can
+ * delay setting bus ops until we're sure every possible SMMU is ready,
+ * and that way ensure that no add_device() calls get missed.
+ */
+static int arm_smmu_legacy_bus_init(void)
+{
+ if (using_legacy_binding)
+ arm_smmu_bus_init();
+ return 0;
+}
+device_initcall_sync(arm_smmu_legacy_bus_init);
+#else
+static int arm_smmu_register_legacy_master(struct device *dev,
+ struct arm_smmu_device **smmu)
+{
+ return -ENODEV;
+}
+#endif /* CONFIG_ARM_SMMU_LEGACY_DT_BINDINGS */
+
static int __arm_smmu_alloc_bitmap(unsigned long *map, int start, int end)
{
int idx;
@@ -1960,8 +1984,10 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev,
legacy_binding = of_find_property(dev->of_node, "mmu-masters", NULL);
if (legacy_binding && !using_generic_binding) {
- if (!using_legacy_binding)
- pr_notice("deprecated \"mmu-masters\" DT property in use; DMA API support unavailable\n");
+ if (!using_legacy_binding) {
+ pr_notice("deprecated \"mmu-masters\" DT property in use; %s support unavailable\n",
+ IS_ENABLED(CONFIG_ARM_SMMU_LEGACY_DT_BINDINGS) ? "DMA API" : "SMMU");
+ }
using_legacy_binding = true;
} else if (!legacy_binding && !using_legacy_binding) {
using_generic_binding = true;
@@ -1986,10 +2012,8 @@ static void arm_smmu_bus_init(void)
bus_set_iommu(&amba_bustype, &arm_smmu_ops);
#endif
#ifdef CONFIG_PCI
- if (!iommu_present(&pci_bus_type)) {
- pci_request_acs();
+ if (!iommu_present(&pci_bus_type))
bus_set_iommu(&pci_bus_type, &arm_smmu_ops);
- }
#endif
#ifdef CONFIG_FSL_MC_BUS
if (!iommu_present(&fsl_mc_bus_type))
@@ -2147,20 +2171,6 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
return 0;
}
-/*
- * With the legacy DT binding in play, though, we have no guarantees about
- * probe order, but then we're also not doing default domains, so we can
- * delay setting bus ops until we're sure every possible SMMU is ready,
- * and that way ensure that no add_device() calls get missed.
- */
-static int arm_smmu_legacy_bus_init(void)
-{
- if (using_legacy_binding)
- arm_smmu_bus_init();
- return 0;
-}
-device_initcall_sync(arm_smmu_legacy_bus_init);
-
static int arm_smmu_device_remove(struct platform_device *pdev)
{
struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
--
2.24.0.rc0.303.g954a862665-goog
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