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Subject[v5 3/4] iommu/arm-smmu-v3: Add workaround for Cavium ThunderX2 erratum #74
Date
From: Linu Cherian <linu.cherian@cavium.com>

Cavium ThunderX2 SMMU implementation doesn't support page 1 register space
and PAGE0_REGS_ONLY option is enabled as an errata workaround.
This option when turned on, replaces all page 1 offsets used for
EVTQ_PROD/CONS, PRIQ_PROD/CONS register access with page 0 offsets.

SMMU resource size checks are now based on SMMU option PAGE0_REGS_ONLY,
since resource size can be either 64k/128k.
For this, arm_smmu_device_dt_probe/acpi_probe has been moved before
platform_get_resource call, so that SMMU options are set beforehand.

Signed-off-by: Linu Cherian <linu.cherian@cavium.com>
Signed-off-by: Geetha Sowjanya <geethasowjanya.akula@cavium.com>
---
Documentation/arm64/silicon-errata.txt | 1 +
.../devicetree/bindings/iommu/arm,smmu-v3.txt | 6 ++
drivers/iommu/arm-smmu-v3.c | 64 +++++++++++++++++-----
3 files changed, 56 insertions(+), 15 deletions(-)

diff --git a/Documentation/arm64/silicon-errata.txt b/Documentation/arm64/silicon-errata.txt
index 10f2ddd..4693a32 100644
--- a/Documentation/arm64/silicon-errata.txt
+++ b/Documentation/arm64/silicon-errata.txt
@@ -62,6 +62,7 @@ stable kernels.
| Cavium | ThunderX GICv3 | #23154 | CAVIUM_ERRATUM_23154 |
| Cavium | ThunderX Core | #27456 | CAVIUM_ERRATUM_27456 |
| Cavium | ThunderX SMMUv2 | #27704 | N/A |
+| Cavium | ThunderX2 SMMUv3| #74 | N/A |
| | | | |
| Freescale/NXP | LS2080A/LS1043A | A-008585 | FSL_ERRATUM_A008585 |
| | | | |
diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
index be57550..e6da62b 100644
--- a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
+++ b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
@@ -49,6 +49,12 @@ the PCIe specification.
- hisilicon,broken-prefetch-cmd
: Avoid sending CMD_PREFETCH_* commands to the SMMU.

+- cavium-cn99xx,broken-page1-regspace
+ : Replaces all page 1 offsets used for EVTQ_PROD/CONS,
+ PRIQ_PROD/CONS register access with page 0 offsets.
+ Set for Caviun ThunderX2 silicon that doesn't support
+ SMMU page1 register space.
+
** Example

smmu@2b400000 {
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 380969a..5836b72 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -412,6 +412,9 @@
#define MSI_IOVA_BASE 0x8000000
#define MSI_IOVA_LENGTH 0x100000

+#define ARM_SMMU_PAGE0_REGS_ONLY(smmu) \
+ ((smmu)->options & ARM_SMMU_OPT_PAGE0_REGS_ONLY)
+
static bool disable_bypass;
module_param_named(disable_bypass, disable_bypass, bool, S_IRUGO);
MODULE_PARM_DESC(disable_bypass,
@@ -597,6 +600,7 @@ struct arm_smmu_device {
u32 features;

#define ARM_SMMU_OPT_SKIP_PREFETCH (1 << 0)
+#define ARM_SMMU_OPT_PAGE0_REGS_ONLY (1 << 1)
u32 options;

struct arm_smmu_cmdq cmdq;
@@ -663,9 +667,19 @@ struct arm_smmu_option_prop {

static struct arm_smmu_option_prop arm_smmu_options[] = {
{ ARM_SMMU_OPT_SKIP_PREFETCH, "hisilicon,broken-prefetch-cmd" },
+ { ARM_SMMU_OPT_PAGE0_REGS_ONLY, "cavium-cn99xx,broken-page1-regspace"},
{ 0, NULL},
};

+static inline void __iomem *arm_smmu_page1_fixup(unsigned long offset,
+ struct arm_smmu_device *smmu)
+{
+ if (offset > SZ_64K && ARM_SMMU_PAGE0_REGS_ONLY(smmu))
+ offset -= SZ_64K;
+
+ return smmu->base + offset;
+}
+
static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
{
return container_of(dom, struct arm_smmu_domain, domain);
@@ -1961,8 +1975,8 @@ static int arm_smmu_init_one_queue(struct arm_smmu_device *smmu,
return -ENOMEM;
}

- q->prod_reg = smmu->base + prod_off;
- q->cons_reg = smmu->base + cons_off;
+ q->prod_reg = arm_smmu_page1_fixup(prod_off, smmu);
+ q->cons_reg = arm_smmu_page1_fixup(cons_off, smmu);
q->ent_dwords = dwords;

q->q_base = Q_BASE_RWA;
@@ -2363,8 +2377,10 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)

/* Event queue */
writeq_relaxed(smmu->evtq.q.q_base, smmu->base + ARM_SMMU_EVTQ_BASE);
- writel_relaxed(smmu->evtq.q.prod, smmu->base + ARM_SMMU_EVTQ_PROD);
- writel_relaxed(smmu->evtq.q.cons, smmu->base + ARM_SMMU_EVTQ_CONS);
+ writel_relaxed(smmu->evtq.q.prod,
+ arm_smmu_page1_fixup(ARM_SMMU_EVTQ_PROD, smmu));
+ writel_relaxed(smmu->evtq.q.cons,
+ arm_smmu_page1_fixup(ARM_SMMU_EVTQ_CONS, smmu));

enables |= CR0_EVTQEN;
ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0,
@@ -2379,9 +2395,9 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
writeq_relaxed(smmu->priq.q.q_base,
smmu->base + ARM_SMMU_PRIQ_BASE);
writel_relaxed(smmu->priq.q.prod,
- smmu->base + ARM_SMMU_PRIQ_PROD);
+ arm_smmu_page1_fixup(ARM_SMMU_PRIQ_PROD, smmu));
writel_relaxed(smmu->priq.q.cons,
- smmu->base + ARM_SMMU_PRIQ_CONS);
+ arm_smmu_page1_fixup(ARM_SMMU_PRIQ_CONS, smmu));

enables |= CR0_PRIQEN;
ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0,
@@ -2605,6 +2621,14 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
}

#ifdef CONFIG_ACPI
+static void acpi_smmu_get_options(u32 model, struct arm_smmu_device *smmu)
+{
+ if (model == ACPI_IORT_SMMU_V3_CAVIUM_CN99XX)
+ smmu->options |= ARM_SMMU_OPT_PAGE0_REGS_ONLY;
+
+ dev_notice(smmu->dev, "option mask 0x%x\n", smmu->options);
+}
+
static int arm_smmu_device_acpi_probe(struct platform_device *pdev,
struct arm_smmu_device *smmu)
{
@@ -2617,6 +2641,8 @@ static int arm_smmu_device_acpi_probe(struct platform_device *pdev,
/* Retrieve SMMUv3 specific data */
iort_smmu = (struct acpi_iort_smmu_v3 *)node->node_data;

+ acpi_smmu_get_options(iort_smmu->model, smmu);
+
if (iort_smmu->flags & ACPI_IORT_SMMU_V3_COHACC_OVERRIDE)
smmu->features |= ARM_SMMU_FEAT_COHERENCY;

@@ -2652,6 +2678,14 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev,
return ret;
}

+static unsigned long arm_smmu_resource_size(struct arm_smmu_device *smmu)
+{
+ if (ARM_SMMU_PAGE0_REGS_ONLY(smmu))
+ return SZ_64K;
+ else
+ return SZ_128K;
+}
+
static int arm_smmu_device_probe(struct platform_device *pdev)
{
int irq, ret;
@@ -2668,9 +2702,17 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
}
smmu->dev = dev;

+ if (dev->of_node) {
+ ret = arm_smmu_device_dt_probe(pdev, smmu);
+ } else {
+ ret = arm_smmu_device_acpi_probe(pdev, smmu);
+ if (ret == -ENODEV)
+ return ret;
+ }
+
/* Base address */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (resource_size(res) + 1 < SZ_128K) {
+ if (resource_size(res) + 1 < arm_smmu_resource_size(smmu)) {
dev_err(dev, "MMIO region too small (%pr)\n", res);
return -EINVAL;
}
@@ -2697,14 +2739,6 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
if (irq > 0)
smmu->gerr_irq = irq;

- if (dev->of_node) {
- ret = arm_smmu_device_dt_probe(pdev, smmu);
- } else {
- ret = arm_smmu_device_acpi_probe(pdev, smmu);
- if (ret == -ENODEV)
- return ret;
- }
-
/* Set bypass mode according to firmware probing result */
bypass = !!ret;

--
1.8.3.1
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