Thread (16 messages) 16 messages, 6 authors, 2021-08-02
STALE1768d
Revisions (10)
  1. v2 [diff vs current]
  2. v3 [diff vs current]
  3. v5 [diff vs current]
  4. v6 current
  5. v7 [diff vs current]
  6. v8 [diff vs current]
  7. v10 [diff vs current]
  8. v11 [diff vs current]
  9. v12 [diff vs current]
  10. v13 [diff vs current]

[PATCH v6 6/9] iommu/arm-smmu-v3: Refactor arm_smmu_init_bypass_stes() to force bypass

From: Shameer Kolothum <hidden>
Date: 2021-07-16 08:39:00
Also in: linux-acpi, linux-iommu
Subsystem: arm smmu drivers, iommu subsystem, the rest · Maintainers: Will Deacon, Joerg Roedel, Linus Torvalds

By default, disable_bypass flag is set and any dev without
an iommu domain installs STE with CFG_ABORT during
arm_smmu_init_bypass_stes(). Introduce a "force" flag and
move the STE update logic to arm_smmu_init_bypass_stes()
so that we can force it to install CFG_BYPASS STE for specific
SIDs.

This will be useful in follow-up patch to install bypass
for IORT RMR SIDs.

Signed-off-by: Shameer Kolothum <redacted>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)
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 33f5556aefeb..34f84641dc6a 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1356,12 +1356,21 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 		arm_smmu_cmdq_issue_cmd(smmu, &prefetch_cmd);
 }
 
-static void arm_smmu_init_bypass_stes(__le64 *strtab, unsigned int nent)
+static void arm_smmu_init_bypass_stes(__le64 *strtab, unsigned int nent, bool force)
 {
 	unsigned int i;
+	u64 val = STRTAB_STE_0_V;
+
+	if (disable_bypass && !force)
+		val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_ABORT);
+	else
+		val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_BYPASS);
 
 	for (i = 0; i < nent; ++i) {
-		arm_smmu_write_strtab_ent(NULL, -1, strtab);
+		strtab[0] = cpu_to_le64(val);
+		strtab[1] = cpu_to_le64(FIELD_PREP(STRTAB_STE_1_SHCFG,
+						   STRTAB_STE_1_SHCFG_INCOMING));
+		strtab[2] = 0;
 		strtab += STRTAB_STE_DWORDS;
 	}
 }
@@ -1389,7 +1398,7 @@ static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid)
 		return -ENOMEM;
 	}
 
-	arm_smmu_init_bypass_stes(desc->l2ptr, 1 << STRTAB_SPLIT);
+	arm_smmu_init_bypass_stes(desc->l2ptr, 1 << STRTAB_SPLIT, false);
 	arm_smmu_write_strtab_l1_desc(strtab, desc);
 	return 0;
 }
@@ -3041,7 +3050,7 @@ static int arm_smmu_init_strtab_linear(struct arm_smmu_device *smmu)
 	reg |= FIELD_PREP(STRTAB_BASE_CFG_LOG2SIZE, smmu->sid_bits);
 	cfg->strtab_base_cfg = reg;
 
-	arm_smmu_init_bypass_stes(strtab, cfg->num_l1_ents);
+	arm_smmu_init_bypass_stes(strtab, cfg->num_l1_ents, false);
 	return 0;
 }
 
-- 
2.17.1


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