[PATCH v9 09/11] iommu/arm-smmu-v3: Refactor arm_smmu_init_bypass_stes() to force bypass

Shameer Kolothum
2022-04-04T12:44:31Z

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 a follow-up patch to install bypass
for IORT RMR SIDs.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
---
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 61558fdabbe3..57f831c44155 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1380,12 +1380,21 @@ 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;
}
}
@@ -1413,7 +1422,7 @@ 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;
}
@@ -3051,7 +3060,7 @@ 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;
}

--
2.25.1