For platform devices that support SubstreamID (SSID), firmware provides
the number of supported SSID bits. Restrict it to what the SMMU supports
and cache it into master->ssid_bits, which will also be used for PCI
PASID.
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
---
drivers/iommu/arm-smmu-v3.c | 13 +++++++++++++
drivers/iommu/of_iommu.c | 6 +++++-
include/linux/iommu.h | 2 ++
3 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index d4e8b7f8d9f4..837b4283b4dc 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -292,6 +292,12 @@
#define CTXDESC_CD_1_TTB0_MASK GENMASK_ULL(51, 4)
+/*
+ * When the SMMU only supports linear context descriptor tables, pick a
+ * reasonable size limit (64kB).
+ */
+#define CTXDESC_LINEAR_CDMAX ilog2(SZ_64K / (CTXDESC_CD_DWORDS << 3))
+
/* Convert between AArch64 (CPU) TCR format and SMMU CD format */
#define ARM_SMMU_TCR2CD(tcr, fld) FIELD_PREP(CTXDESC_CD_0_TCR_##fld, \
FIELD_GET(ARM64_TCR_##fld, tcr))
@@ -638,6 +644,7 @@ struct arm_smmu_master {
u32 *sids;
unsigned int num_sids;
bool ats_enabled;
+ unsigned int ssid_bits;
};
/* SMMU private data for an IOMMU domain */
@@ -2571,6 +2578,12 @@ static int arm_smmu_add_device(struct device *dev)
}
}
+ master->ssid_bits = min(smmu->ssid_bits, fwspec->num_pasid_bits);
+
+ if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_CDTAB))
+ master->ssid_bits = min_t(u8, master->ssid_bits,
+ CTXDESC_LINEAR_CDMAX);
+
group = iommu_group_get_for_dev(dev);
if (!IS_ERR(group)) {
iommu_group_put(group);
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 026ad2b29dcd..b3ccb2f7f1c7 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -196,8 +196,12 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
if (err)
break;
}
- }
+ fwspec = dev_iommu_fwspec_get(dev);
+ if (!err && fwspec)
+ of_property_read_u32(master_np, "pasid-num-bits",
+ &fwspec->num_pasid_bits);
+ }
/*
* Two success conditions can be represented by non-negative err here:
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index f2223cbb5fd5..956031eab3ef 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -570,6 +570,7 @@ struct iommu_group *fsl_mc_device_group(struct device *dev);
* @ops: ops for this device's IOMMU
* @iommu_fwnode: firmware handle for this device's IOMMU
* @iommu_priv: IOMMU driver private data for this device
+ * @num_pasid_bits: number of PASID bits supported by this device
* @num_ids: number of associated device IDs
* @ids: IDs which this device may present to the IOMMU
*/
@@ -578,6 +579,7 @@ struct iommu_fwspec {
struct fwnode_handle *iommu_fwnode;
void *iommu_priv;
u32 flags;
+ u32 num_pasid_bits;
unsigned int num_ids;
u32 ids[1];
};
--
2.24.1
