Enable the Extended Stream ID feature when available.

This patch on top of series "[PATCH v7 00/19] KVM PCIe/MSI passthrough
on ARM/ARM64 and IOVA reserved regions" by Eric Auger allows
to passthrough an external PCIe network card on a ThunderX server
successfully.

Without this patch that card caused a warning like

        pci 0006:90:00.0: stream ID 0x9000 out of range for SMMU (0x7fff)

during boot.

Signed-off-by: Aleksey Makarov <aleksey.maka...@linaro.org>
---
 drivers/iommu/arm-smmu.c | 53 +++++++++++++++++++++++++++++++++---------------
 1 file changed, 37 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 13d26009b8e0..d160c12828f4 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -24,6 +24,7 @@
  *     - v7/v8 long-descriptor format
  *     - Non-secure access to the SMMU
  *     - Context fault reporting
+ *     - Extended Stream ID (16 bit)
  */
 
 #define pr_fmt(fmt) "arm-smmu: " fmt
@@ -87,6 +88,7 @@
 #define sCR0_CLIENTPD                  (1 << 0)
 #define sCR0_GFRE                      (1 << 1)
 #define sCR0_GFIE                      (1 << 2)
+#define sCR0_EXIDENABLE                        (1 << 3)
 #define sCR0_GCFGFRE                   (1 << 4)
 #define sCR0_GCFGFIE                   (1 << 5)
 #define sCR0_USFCFG                    (1 << 10)
@@ -126,6 +128,7 @@
 #define ID0_NUMIRPT_MASK               0xff
 #define ID0_NUMSIDB_SHIFT              9
 #define ID0_NUMSIDB_MASK               0xf
+#define ID0_EXIDS                      (1 << 8)
 #define ID0_NUMSMRG_SHIFT              0
 #define ID0_NUMSMRG_MASK               0xff
 
@@ -169,6 +172,7 @@
 #define ARM_SMMU_GR0_S2CR(n)           (0xc00 + ((n) << 2))
 #define S2CR_CBNDX_SHIFT               0
 #define S2CR_CBNDX_MASK                        0xff
+#define S2CR_EXIDVALID                 (1 << 10)
 #define S2CR_TYPE_SHIFT                        16
 #define S2CR_TYPE_MASK                 0x3
 enum arm_smmu_s2cr_type {
@@ -354,6 +358,7 @@ struct arm_smmu_device {
 #define ARM_SMMU_FEAT_FMT_AARCH64_64K  (1 << 9)
 #define ARM_SMMU_FEAT_FMT_AARCH32_L    (1 << 10)
 #define ARM_SMMU_FEAT_FMT_AARCH32_S    (1 << 11)
+#define ARM_SMMU_FEAT_EXIDS            (1 << 12)
        u32                             features;
 
 #define ARM_SMMU_OPT_SECURE_CFG_ACCESS (1 << 0)
@@ -1051,7 +1056,7 @@ static void arm_smmu_write_smr(struct arm_smmu_device 
*smmu, int idx)
        struct arm_smmu_smr *smr = smmu->smrs + idx;
        u32 reg = smr->id << SMR_ID_SHIFT | smr->mask << SMR_MASK_SHIFT;
 
-       if (smr->valid)
+       if (!(smmu->features & ARM_SMMU_FEAT_EXIDS) && smr->valid)
                reg |= SMR_VALID;
        writel_relaxed(reg, ARM_SMMU_GR0(smmu) + ARM_SMMU_GR0_SMR(idx));
 }
@@ -1063,6 +1068,9 @@ static void arm_smmu_write_s2cr(struct arm_smmu_device 
*smmu, int idx)
                  (s2cr->cbndx & S2CR_CBNDX_MASK) << S2CR_CBNDX_SHIFT |
                  (s2cr->privcfg & S2CR_PRIVCFG_MASK) << S2CR_PRIVCFG_SHIFT;
 
+       if (smmu->features & ARM_SMMU_FEAT_EXIDS && smmu->smrs &&
+           smmu->smrs[idx].valid)
+               reg |= S2CR_EXIDVALID;
        writel_relaxed(reg, ARM_SMMU_GR0(smmu) + ARM_SMMU_GR0_S2CR(idx));
 }
 
@@ -1674,6 +1682,9 @@ static void arm_smmu_device_reset(struct arm_smmu_device 
*smmu)
        if (smmu->features & ARM_SMMU_FEAT_VMID16)
                reg |= sCR0_VMID16EN;
 
+       if (smmu->features & ARM_SMMU_FEAT_EXIDS)
+               reg |= sCR0_EXIDENABLE;
+
        /* Push the button */
        __arm_smmu_tlb_sync(smmu);
        writel(reg, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0);
@@ -1761,7 +1772,12 @@ static int arm_smmu_device_cfg_probe(struct 
arm_smmu_device *smmu)
                           "\t(IDR0.CTTW overridden by FW configuration)\n");
 
        /* Max. number of entries we have for stream matching/indexing */
-       size = 1 << ((id >> ID0_NUMSIDB_SHIFT) & ID0_NUMSIDB_MASK);
+       if (smmu->version == ARM_SMMU_V2 && id & ID0_EXIDS) {
+               smmu->features |= ARM_SMMU_FEAT_EXIDS;
+               size = (1 << 16);
+       } else {
+               size = 1 << ((id >> ID0_NUMSIDB_SHIFT) & ID0_NUMSIDB_MASK);
+       }
        smmu->streamid_mask = size - 1;
        if (id & ID0_SMS) {
                u32 smr;
@@ -1774,20 +1790,25 @@ static int arm_smmu_device_cfg_probe(struct 
arm_smmu_device *smmu)
                        return -ENODEV;
                }
 
-               /*
-                * SMR.ID bits may not be preserved if the corresponding MASK
-                * bits are set, so check each one separately. We can reject
-                * masters later if they try to claim IDs outside these masks.
-                */
-               smr = smmu->streamid_mask << SMR_ID_SHIFT;
-               writel_relaxed(smr, gr0_base + ARM_SMMU_GR0_SMR(0));
-               smr = readl_relaxed(gr0_base + ARM_SMMU_GR0_SMR(0));
-               smmu->streamid_mask = smr >> SMR_ID_SHIFT;
-
-               smr = smmu->streamid_mask << SMR_MASK_SHIFT;
-               writel_relaxed(smr, gr0_base + ARM_SMMU_GR0_SMR(0));
-               smr = readl_relaxed(gr0_base + ARM_SMMU_GR0_SMR(0));
-               smmu->smr_mask_mask = smr >> SMR_MASK_SHIFT;
+               if (smmu->features & ARM_SMMU_FEAT_EXIDS) {
+                       smmu->smr_mask_mask = smmu->streamid_mask;
+               } else {
+                       /*
+                        * SMR.ID bits may not be preserved if the corresponding
+                        * MASK bits are set, so check each one separately.
+                        * We can reject masters later if they try to claim IDs
+                        * outside these masks.
+                        */
+                       smr = smmu->streamid_mask << SMR_ID_SHIFT;
+                       writel_relaxed(smr, gr0_base + ARM_SMMU_GR0_SMR(0));
+                       smr = readl_relaxed(gr0_base + ARM_SMMU_GR0_SMR(0));
+                       smmu->streamid_mask = smr >> SMR_ID_SHIFT;
+
+                       smr = smmu->streamid_mask << SMR_MASK_SHIFT;
+                       writel_relaxed(smr, gr0_base + ARM_SMMU_GR0_SMR(0));
+                       smr = readl_relaxed(gr0_base + ARM_SMMU_GR0_SMR(0));
+                       smmu->smr_mask_mask = smr >> SMR_MASK_SHIFT;
+               }
 
                /* Zero-initialised to mark as invalid */
                smmu->smrs = devm_kcalloc(smmu->dev, size, sizeof(*smmu->smrs),
-- 
2.11.0

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