[PATCH v3 1/5] iommu/arm-smmu: to support probe deferral
Zhen Lei
thunder.leizhen at huawei.com
Tue Jul 21 00:30:29 PDT 2015
For pci devices, only the root nodes have "iommus" property. So we
should traverse all of its sub nodes in of_xlate.
There exists two cases:
Case 1: .add_device(sub node) happened before .of_xlate(root node)
Case 2: .add_device(sub node) happened after .of_xlate(root node)
(1).add_device
if (!root->archdata.iommu)
return -ENODEV;
(2).of_xlate
root->archdata.iommu = smmu;
/*
* Probe the pci devices deferred in phase (1)
*/
(3).add_device
/*
* After phase (2), it's not NULL
*/
if (!root->archdata.iommu)
return -ENODEV;
__arm_smmu_add_pci_device(pdev, root->archdata.iommu);
Reviewed-by: Robin Murphy <robin.murphy at arm.com>
Signed-off-by: Zhen Lei <thunder.leizhen at huawei.com>
---
drivers/iommu/arm-smmu-v3.c | 147 +++++++++++++++++++++++++++++++++++---------
1 file changed, 117 insertions(+), 30 deletions(-)
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 4f09337..474eca4 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -30,6 +30,8 @@
#include <linux/of_address.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
+#include <linux/of_iommu.h>
+#include <linux/of_platform.h>
#include "io-pgtable.h"
@@ -1741,32 +1743,37 @@ static void __arm_smmu_release_pci_iommudata(void *data)
kfree(data);
}
-static struct arm_smmu_device *arm_smmu_get_for_pci_dev(struct pci_dev *pdev)
+static struct arm_smmu_device *find_smmu_by_device(struct device *dev)
+{
+ struct device_node *np = dev->of_node;
+
+ /* to ensure np is a smmu device node */
+ if (!of_iommu_get_ops(np))
+ return NULL;
+
+ return dev->archdata.iommu;
+}
+
+static struct arm_smmu_device *find_smmu_by_node(struct device_node *np)
+{
+ struct platform_device *pdev;
+
+ pdev = of_find_device_by_node(np);
+ if (!pdev)
+ return NULL;
+
+ return find_smmu_by_device(&pdev->dev);
+}
+
+static struct device *arm_smmu_get_pci_dev_root(struct pci_dev *pdev)
{
- struct device_node *of_node;
- struct arm_smmu_device *curr, *smmu = NULL;
struct pci_bus *bus = pdev->bus;
/* Walk up to the root bus */
while (!pci_is_root_bus(bus))
bus = bus->parent;
- /* Follow the "iommus" phandle from the host controller */
- of_node = of_parse_phandle(bus->bridge->parent->of_node, "iommus", 0);
- if (!of_node)
- return NULL;
-
- /* See if we can find an SMMU corresponding to the phandle */
- spin_lock(&arm_smmu_devices_lock);
- list_for_each_entry(curr, &arm_smmu_devices, list) {
- if (curr->dev->of_node == of_node) {
- smmu = curr;
- break;
- }
- }
- spin_unlock(&arm_smmu_devices_lock);
- of_node_put(of_node);
- return smmu;
+ return bus->bridge->parent;
}
static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
@@ -1779,27 +1786,21 @@ static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
return sid < limit;
}
-static int arm_smmu_add_device(struct device *dev)
+static int __arm_smmu_add_device(struct device *dev, u32 sid)
{
int i, ret;
- u32 sid, *sids;
- struct pci_dev *pdev;
+ u32 *sids;
struct iommu_group *group;
struct arm_smmu_group *smmu_group;
struct arm_smmu_device *smmu;
- /* We only support PCI, for now */
- if (!dev_is_pci(dev))
- return -ENODEV;
-
- pdev = to_pci_dev(dev);
group = iommu_group_get_for_dev(dev);
if (IS_ERR(group))
return PTR_ERR(group);
smmu_group = iommu_group_get_iommudata(group);
if (!smmu_group) {
- smmu = arm_smmu_get_for_pci_dev(pdev);
+ smmu = dev->archdata.iommu;
if (!smmu) {
ret = -ENOENT;
goto out_put_group;
@@ -1819,8 +1820,6 @@ static int arm_smmu_add_device(struct device *dev)
smmu = smmu_group->smmu;
}
- /* Assume SID == RID until firmware tells us otherwise */
- pci_for_each_dma_alias(pdev, __arm_smmu_get_pci_sid, &sid);
for (i = 0; i < smmu_group->num_sids; ++i) {
/* If we already know about this SID, then we're done */
if (smmu_group->sids[i] == sid)
@@ -1857,11 +1856,43 @@ static int arm_smmu_add_device(struct device *dev)
out_put_group:
iommu_group_put(group);
+ dev_err(dev, "failed to add into SMMU\n");
return ret;
}
+static int __arm_smmu_add_pci_device(struct pci_dev *pdev, void *smmu)
+{
+ u32 sid;
+ struct device *dev = &pdev->dev;
+
+ /* Assume SID == RID until firmware tells us otherwise */
+ pci_for_each_dma_alias(pdev, __arm_smmu_get_pci_sid, &sid);
+
+ dev->archdata.iommu = smmu;
+
+ return __arm_smmu_add_device(dev, sid);
+}
+
+static int arm_smmu_add_device(struct device *dev)
+{
+ struct pci_dev *pdev;
+ struct device *root;
+
+ /* only support pci devices hotplug */
+ if (!dev_is_pci(dev))
+ return -ENODEV;
+
+ pdev = to_pci_dev(dev);
+ root = arm_smmu_get_pci_dev_root(pdev);
+ if (!root->archdata.iommu)
+ return -ENODEV;
+
+ return __arm_smmu_add_pci_device(pdev, root->archdata.iommu);
+}
+
static void arm_smmu_remove_device(struct device *dev)
{
+ dev->archdata.iommu = NULL;
iommu_group_remove_device(dev);
}
@@ -1909,7 +1940,58 @@ out_unlock:
return ret;
}
+static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args)
+{
+ int ret;
+ struct arm_smmu_device *smmu;
+
+ /*
+ * We can sure that args->np is a smmu device node, because this
+ * function was called by of_xlate hook.
+ *
+ * And in arm_smmu_device_dt_probe:
+ * dev->archdata.iommu = smmu;
+ * of_iommu_set_ops(smmu->dev->of_node, &arm_smmu_ops);
+ *
+ * It seems impossible return NULL in normal times.
+ */
+ smmu = find_smmu_by_node(args->np);
+ if (!smmu) {
+ dev_err(dev, "unknown error caused smmu driver crashed\n");
+ return -ENODEV;
+ }
+
+ if (!dev->archdata.iommu)
+ dev->archdata.iommu = smmu;
+
+ if (dev->archdata.iommu != smmu) {
+ dev_err(dev, "behinds more than one smmu\n");
+ return -EINVAL;
+ }
+
+ /* We only support PCI, for now */
+ if (!dev_is_pci(dev)) {
+ return -ENODEV;
+ } else {
+ struct device *root;
+ struct pci_dev *pdev = NULL;
+
+ for_each_pci_dev(pdev) {
+ root = arm_smmu_get_pci_dev_root(pdev);
+ if (root->of_node != dev->of_node)
+ continue;
+
+ ret = __arm_smmu_add_pci_device(pdev, smmu);
+ if (ret)
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
static struct iommu_ops arm_smmu_ops = {
+ .of_xlate = arm_smmu_of_xlate,
.capable = arm_smmu_capable,
.domain_alloc = arm_smmu_domain_alloc,
.domain_free = arm_smmu_domain_free,
@@ -2635,6 +2717,9 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
spin_lock(&arm_smmu_devices_lock);
list_add(&smmu->list, &arm_smmu_devices);
spin_unlock(&arm_smmu_devices_lock);
+ dev->archdata.iommu = smmu;
+ of_iommu_set_ops(smmu->dev->of_node, &arm_smmu_ops);
+
return 0;
out_free_structures:
@@ -2706,6 +2791,8 @@ static void __exit arm_smmu_exit(void)
subsys_initcall(arm_smmu_init);
module_exit(arm_smmu_exit);
+IOMMU_OF_DECLARE(arm_smmu_v3, "arm,smmu-v3", NULL);
+
MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
MODULE_AUTHOR("Will Deacon <will.deacon at arm.com>");
MODULE_LICENSE("GPL v2");
--
1.8.0
More information about the linux-arm-kernel
mailing list