[PATCH v11 8/9] iommu/arm-smmu-v3: Get associated RMR info and install bypass STE

Shameer Kolothum
2022-04-22T16:30:54Z

Check if there is any RMR info associated with the devices behind
the SMMUv3 and if any, install bypass STEs for them. This is to
keep any ongoing traffic associated with these devices alive
when we enable/reset SMMUv3 during probe().

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 33 +++++++++++++++++++++
1 file changed, 33 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index a939d9e0f747..8a5dfd078e95 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3754,6 +3754,36 @@ static void __iomem *arm_smmu_ioremap(struct device *dev, resource_size_t start,
return devm_ioremap_resource(dev, &res);
}

+static void arm_smmu_rmr_install_bypass_ste(struct arm_smmu_device *smmu)
+{
+ struct list_head rmr_list;
+ struct iommu_resv_region *e;
+
+ INIT_LIST_HEAD(&rmr_list);
+ iort_get_rmr_sids(dev_fwnode(smmu->dev), &rmr_list);
+
+ list_for_each_entry(e, &rmr_list, list) {
+ __le64 *step;
+ struct iommu_iort_rmr_data *rmr;
+ int ret, i;
+
+ rmr = container_of(e, struct iommu_iort_rmr_data, rr);
+ for (i = 0; i < rmr->num_sids; i++) {
+ ret = arm_smmu_init_sid_strtab(smmu, rmr->sids[i]);
+ if (ret) {
+ dev_err(smmu->dev, "RMR SID(0x%x) bypass failed\n",
+ rmr->sids[i]);
+ continue;
+ }
+
+ step = arm_smmu_get_step_for_sid(smmu, rmr->sids[i]);
+ arm_smmu_init_bypass_stes(step, 1, true);
+ }
+ }
+
+ iort_put_rmr_sids(dev_fwnode(smmu->dev), &rmr_list);
+}
+
static int arm_smmu_device_probe(struct platform_device *pdev)
{
int irq, ret;
@@ -3835,6 +3865,9 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
/* Record our private device structure */
platform_set_drvdata(pdev, smmu);

+ /* Check for RMRs and install bypass STEs if any */
+ arm_smmu_rmr_install_bypass_ste(smmu);
+
/* Reset the device */
ret = arm_smmu_device_reset(smmu, bypass);
if (ret)
--
2.17.1