Re: [PATCH] iommu/arm: Expose ARM SMMUv3 related registers via sysfs
From: Robin Murphy
Date: Wed Mar 23 2022 - 09:40:57 EST
On 2022-03-23 12:54, Miguel Luis wrote:
Allows userspace to check for SMMUv3 features.
What will userspace do with that information?
It hardly matters what fancy new features might be present, if the
kernel and/or the abstracted interfaces available to userspace aren't
using them. Any functionality which is supported by a usable interface
should ideally be represented via that interface itself.
Furthermore many of the raw SMMU features depend on other system
components and/or firmware, so the ID registers alone don't tell the
full story anyway.
Expose the following RO registers related to ARM SMMUv3 via sysfs:
SMMU_IDR0
SMMU_IDR1
SMMU_IDR2
SMMU_IDR3
SMMU_IDR4
SMMU_IDR5
SMMU_IDR6
SMMU_IIDR
SMMU_AIDR
# find /sys | grep arm-iommu
/sys/devices/platform/9050000.smmuv3/iommu/smmu3.0x0000000009050000/arm-iommu
Nit: my main comment above notwithstanding, is this level of hierarchcy
meaningful or useful? "arm-iommu" isn't an established name for anything
as far as I'm aware.
Robin.
/sys/devices/platform/9050000.smmuv3/iommu/smmu3.0x0000000009050000/arm-iommu/smmu_idr5
/sys/devices/platform/9050000.smmuv3/iommu/smmu3.0x0000000009050000/arm-iommu/smmu_idr3
/sys/devices/platform/9050000.smmuv3/iommu/smmu3.0x0000000009050000/arm-iommu/smmu_idr1
/sys/devices/platform/9050000.smmuv3/iommu/smmu3.0x0000000009050000/arm-iommu/smmu_aidr
/sys/devices/platform/9050000.smmuv3/iommu/smmu3.0x0000000009050000/arm-iommu/smmu_idr6
/sys/devices/platform/9050000.smmuv3/iommu/smmu3.0x0000000009050000/arm-iommu/smmu_idr4
/sys/devices/platform/9050000.smmuv3/iommu/smmu3.0x0000000009050000/arm-iommu/smmu_iidr
/sys/devices/platform/9050000.smmuv3/iommu/smmu3.0x0000000009050000/arm-iommu/smmu_idr2
/sys/devices/platform/9050000.smmuv3/iommu/smmu3.0x0000000009050000/arm-iommu/smmu_idr0
Signed-off-by: Miguel Luis <miguel.luis@xxxxxxxxxx>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 199 ++++++++++++++++----
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 27 +++
2 files changed, 191 insertions(+), 35 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 6dc6d8b6b368..7f779d3f88f2 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3424,17 +3424,16 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
{
- u32 reg;
bool coherent = smmu->features & ARM_SMMU_FEAT_COHERENCY;
/* IDR0 */
- reg = readl_relaxed(smmu->base + ARM_SMMU_IDR0);
+ smmu->idr0 = readl_relaxed(smmu->base + ARM_SMMU_IDR0);
/* 2-level structures */
- if (FIELD_GET(IDR0_ST_LVL, reg) == IDR0_ST_LVL_2LVL)
+ if (FIELD_GET(IDR0_ST_LVL, smmu->idr0) == IDR0_ST_LVL_2LVL)
smmu->features |= ARM_SMMU_FEAT_2_LVL_STRTAB;
- if (reg & IDR0_CD2L)
+ if (smmu->idr0 & IDR0_CD2L)
smmu->features |= ARM_SMMU_FEAT_2_LVL_CDTAB;
/*
@@ -3442,7 +3441,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
* We currently require the same endianness as the CPU, but this
* could be changed later by adding a new IO_PGTABLE_QUIRK.
*/
- switch (FIELD_GET(IDR0_TTENDIAN, reg)) {
+ switch (FIELD_GET(IDR0_TTENDIAN, smmu->idr0)) {
case IDR0_TTENDIAN_MIXED:
smmu->features |= ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE;
break;
@@ -3461,22 +3460,22 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
}
/* Boolean feature flags */
- if (IS_ENABLED(CONFIG_PCI_PRI) && reg & IDR0_PRI)
+ if (IS_ENABLED(CONFIG_PCI_PRI) && smmu->idr0 & IDR0_PRI)
smmu->features |= ARM_SMMU_FEAT_PRI;
- if (IS_ENABLED(CONFIG_PCI_ATS) && reg & IDR0_ATS)
+ if (IS_ENABLED(CONFIG_PCI_ATS) && smmu->idr0 & IDR0_ATS)
smmu->features |= ARM_SMMU_FEAT_ATS;
- if (reg & IDR0_SEV)
+ if (smmu->idr0 & IDR0_SEV)
smmu->features |= ARM_SMMU_FEAT_SEV;
- if (reg & IDR0_MSI) {
+ if (smmu->idr0 & IDR0_MSI) {
smmu->features |= ARM_SMMU_FEAT_MSI;
if (coherent && !disable_msipolling)
smmu->options |= ARM_SMMU_OPT_MSIPOLL;
}
- if (reg & IDR0_HYP) {
+ if (smmu->idr0 & IDR0_HYP) {
smmu->features |= ARM_SMMU_FEAT_HYP;
if (cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN))
smmu->features |= ARM_SMMU_FEAT_E2H;
@@ -3486,11 +3485,11 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
* The coherency feature as set by FW is used in preference to the ID
* register, but warn on mismatch.
*/
- if (!!(reg & IDR0_COHACC) != coherent)
+ if (!!(smmu->idr0 & IDR0_COHACC) != coherent)
dev_warn(smmu->dev, "IDR0.COHACC overridden by FW configuration (%s)\n",
coherent ? "true" : "false");
- switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
+ switch (FIELD_GET(IDR0_STALL_MODEL, smmu->idr0)) {
case IDR0_STALL_MODEL_FORCE:
smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;
fallthrough;
@@ -3498,19 +3497,19 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
smmu->features |= ARM_SMMU_FEAT_STALLS;
}
- if (reg & IDR0_S1P)
+ if (smmu->idr0 & IDR0_S1P)
smmu->features |= ARM_SMMU_FEAT_TRANS_S1;
- if (reg & IDR0_S2P)
+ if (smmu->idr0 & IDR0_S2P)
smmu->features |= ARM_SMMU_FEAT_TRANS_S2;
- if (!(reg & (IDR0_S1P | IDR0_S2P))) {
+ if (!(smmu->idr0 & (IDR0_S1P | IDR0_S2P))) {
dev_err(smmu->dev, "no translation support!\n");
return -ENXIO;
}
/* We only support the AArch64 table format at present */
- switch (FIELD_GET(IDR0_TTF, reg)) {
+ switch (FIELD_GET(IDR0_TTF, smmu->idr0)) {
case IDR0_TTF_AARCH32_64:
smmu->ias = 40;
fallthrough;
@@ -3522,19 +3521,20 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
}
/* ASID/VMID sizes */
- smmu->asid_bits = reg & IDR0_ASID16 ? 16 : 8;
- smmu->vmid_bits = reg & IDR0_VMID16 ? 16 : 8;
+ smmu->asid_bits = smmu->idr0 & IDR0_ASID16 ? 16 : 8;
+ smmu->vmid_bits = smmu->idr0 & IDR0_VMID16 ? 16 : 8;
/* IDR1 */
- reg = readl_relaxed(smmu->base + ARM_SMMU_IDR1);
- if (reg & (IDR1_TABLES_PRESET | IDR1_QUEUES_PRESET | IDR1_REL)) {
+ smmu->idr1 = readl_relaxed(smmu->base + ARM_SMMU_IDR1);
+
+ if (smmu->idr1 & (IDR1_TABLES_PRESET | IDR1_QUEUES_PRESET | IDR1_REL)) {
dev_err(smmu->dev, "embedded implementation not supported\n");
return -ENXIO;
}
/* Queue sizes, capped to ensure natural alignment */
smmu->cmdq.q.llq.max_n_shift = min_t(u32, CMDQ_MAX_SZ_SHIFT,
- FIELD_GET(IDR1_CMDQS, reg));
+ FIELD_GET(IDR1_CMDQS, smmu->idr1));
if (smmu->cmdq.q.llq.max_n_shift <= ilog2(CMDQ_BATCH_ENTRIES)) {
/*
* We don't support splitting up batches, so one batch of
@@ -3548,13 +3548,13 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
}
smmu->evtq.q.llq.max_n_shift = min_t(u32, EVTQ_MAX_SZ_SHIFT,
- FIELD_GET(IDR1_EVTQS, reg));
+ FIELD_GET(IDR1_EVTQS, smmu->idr1));
smmu->priq.q.llq.max_n_shift = min_t(u32, PRIQ_MAX_SZ_SHIFT,
- FIELD_GET(IDR1_PRIQS, reg));
+ FIELD_GET(IDR1_PRIQS, smmu->idr1));
/* SID/SSID sizes */
- smmu->ssid_bits = FIELD_GET(IDR1_SSIDSIZE, reg);
- smmu->sid_bits = FIELD_GET(IDR1_SIDSIZE, reg);
+ smmu->ssid_bits = FIELD_GET(IDR1_SSIDSIZE, smmu->idr1);
+ smmu->sid_bits = FIELD_GET(IDR1_SIDSIZE, smmu->idr1);
/*
* If the SMMU supports fewer bits than would fill a single L2 stream
@@ -3563,31 +3563,37 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
if (smmu->sid_bits <= STRTAB_SPLIT)
smmu->features &= ~ARM_SMMU_FEAT_2_LVL_STRTAB;
+ /* IDR2 */
+ smmu->idr2 = readl_relaxed(smmu->base + ARM_SMMU_IDR2);
+
/* IDR3 */
- reg = readl_relaxed(smmu->base + ARM_SMMU_IDR3);
- if (FIELD_GET(IDR3_RIL, reg))
+ smmu->idr3 = readl_relaxed(smmu->base + ARM_SMMU_IDR3);
+ if (FIELD_GET(IDR3_RIL, smmu->idr3))
smmu->features |= ARM_SMMU_FEAT_RANGE_INV;
+ /* IDR4 */
+ smmu->idr4 = readl_relaxed(smmu->base + ARM_SMMU_IDR4);
+
/* IDR5 */
- reg = readl_relaxed(smmu->base + ARM_SMMU_IDR5);
+ smmu->idr5 = readl_relaxed(smmu->base + ARM_SMMU_IDR5);
/* Maximum number of outstanding stalls */
- smmu->evtq.max_stalls = FIELD_GET(IDR5_STALL_MAX, reg);
+ smmu->evtq.max_stalls = FIELD_GET(IDR5_STALL_MAX, smmu->idr5);
/* Page sizes */
- if (reg & IDR5_GRAN64K)
+ if (smmu->idr5 & IDR5_GRAN64K)
smmu->pgsize_bitmap |= SZ_64K | SZ_512M;
- if (reg & IDR5_GRAN16K)
+ if (smmu->idr5 & IDR5_GRAN16K)
smmu->pgsize_bitmap |= SZ_16K | SZ_32M;
- if (reg & IDR5_GRAN4K)
+ if (smmu->idr5 & IDR5_GRAN4K)
smmu->pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
/* Input address size */
- if (FIELD_GET(IDR5_VAX, reg) == IDR5_VAX_52_BIT)
+ if (FIELD_GET(IDR5_VAX, smmu->idr5) == IDR5_VAX_52_BIT)
smmu->features |= ARM_SMMU_FEAT_VAX;
/* Output address size */
- switch (FIELD_GET(IDR5_OAS, reg)) {
+ switch (FIELD_GET(IDR5_OAS, smmu->idr5)) {
case IDR5_OAS_32_BIT:
smmu->oas = 32;
break;
@@ -3632,6 +3638,16 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
dev_info(smmu->dev, "ias %lu-bit, oas %lu-bit (features 0x%08x)\n",
smmu->ias, smmu->oas, smmu->features);
+
+ /* IDR6 */
+ smmu->idr6 = readl_relaxed(smmu->base + ARM_SMMU_IDR6);
+
+ /* IIDR */
+ smmu->iidr = readl_relaxed(smmu->base + ARM_SMMU_IIDR);
+
+ /* AIDR */
+ smmu->aidr = readl_relaxed(smmu->base + ARM_SMMU_AIDR);
+
return 0;
}
@@ -3752,6 +3768,119 @@ static void __iomem *arm_smmu_ioremap(struct device *dev, resource_size_t start,
return devm_ioremap_resource(dev, &res);
}
+static ssize_t smmu_idr0_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct arm_smmu_device *smmu = dev_to_arm_smmu_device(dev);
+
+ return sprintf(buf, "%x\n", smmu->idr0);
+}
+static DEVICE_ATTR_RO(smmu_idr0);
+
+static ssize_t smmu_idr1_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct arm_smmu_device *smmu = dev_to_arm_smmu_device(dev);
+
+ return sprintf(buf, "%x\n", smmu->idr1);
+}
+static DEVICE_ATTR_RO(smmu_idr1);
+
+static ssize_t smmu_idr2_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct arm_smmu_device *smmu = dev_to_arm_smmu_device(dev);
+
+ return sprintf(buf, "%x\n", smmu->idr2);
+}
+static DEVICE_ATTR_RO(smmu_idr2);
+
+static ssize_t smmu_idr3_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct arm_smmu_device *smmu = dev_to_arm_smmu_device(dev);
+
+ return sprintf(buf, "%x\n", smmu->idr3);
+}
+static DEVICE_ATTR_RO(smmu_idr3);
+
+static ssize_t smmu_idr4_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct arm_smmu_device *smmu = dev_to_arm_smmu_device(dev);
+
+ return sprintf(buf, "%x\n", smmu->idr4);
+}
+static DEVICE_ATTR_RO(smmu_idr4);
+
+static ssize_t smmu_idr5_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct arm_smmu_device *smmu = dev_to_arm_smmu_device(dev);
+
+ return sprintf(buf, "%x\n", smmu->idr5);
+}
+static DEVICE_ATTR_RO(smmu_idr5);
+
+static ssize_t smmu_idr6_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct arm_smmu_device *smmu = dev_to_arm_smmu_device(dev);
+
+ return sprintf(buf, "%x\n", smmu->idr6);
+}
+static DEVICE_ATTR_RO(smmu_idr6);
+
+static ssize_t smmu_iidr_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct arm_smmu_device *smmu = dev_to_arm_smmu_device(dev);
+
+ return sprintf(buf, "%x\n", smmu->iidr);
+}
+static DEVICE_ATTR_RO(smmu_iidr);
+
+static ssize_t smmu_aidr_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct arm_smmu_device *smmu = dev_to_arm_smmu_device(dev);
+
+ return sprintf(buf, "%x\n", smmu->aidr);
+}
+static DEVICE_ATTR_RO(smmu_aidr);
+
+static struct attribute *arm_iommu_attrs[] = {
+ &dev_attr_smmu_idr0.attr,
+ &dev_attr_smmu_idr1.attr,
+ &dev_attr_smmu_idr2.attr,
+ &dev_attr_smmu_idr3.attr,
+ &dev_attr_smmu_idr4.attr,
+ &dev_attr_smmu_idr5.attr,
+ &dev_attr_smmu_idr6.attr,
+ &dev_attr_smmu_iidr.attr,
+ &dev_attr_smmu_aidr.attr,
+ NULL,
+};
+
+static struct attribute_group arm_iommu_group = {
+ .name = "arm-iommu",
+ .attrs = arm_iommu_attrs,
+};
+
+static const struct attribute_group *arm_iommu_groups[] = {
+ &arm_iommu_group,
+ NULL,
+};
+
static int arm_smmu_device_probe(struct platform_device *pdev)
{
int irq, ret;
@@ -3839,7 +3968,7 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
return ret;
/* And we're up. Go go go! */
- ret = iommu_device_sysfs_add(&smmu->iommu, dev, NULL,
+ ret = iommu_device_sysfs_add(&smmu->iommu, dev, arm_iommu_groups,
"smmu3.%pa", &ioaddr);
if (ret)
return ret;
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index cd48590ada30..ffa1123bf37c 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -50,9 +50,13 @@
#define IDR1_SSIDSIZE GENMASK(10, 6)
#define IDR1_SIDSIZE GENMASK(5, 0)
+#define ARM_SMMU_IDR2 0x8
+
#define ARM_SMMU_IDR3 0xc
#define IDR3_RIL (1 << 10)
+#define ARM_SMMU_IDR4 0x10
+
#define ARM_SMMU_IDR5 0x14
#define IDR5_STALL_MAX GENMASK(31, 16)
#define IDR5_GRAN64K (1 << 6)
@@ -69,6 +73,9 @@
#define IDR5_VAX GENMASK(11, 10)
#define IDR5_VAX_52_BIT 1
+#define ARM_SMMU_IIDR 0x18
+#define ARM_SMMU_AIDR 0x1C
+
#define ARM_SMMU_CR0 0x20
#define CR0_ATSCHK (1 << 4)
#define CR0_CMDQEN (1 << 3)
@@ -154,6 +161,8 @@
#define ARM_SMMU_REG_SZ 0xe00
+#define ARM_SMMU_IDR6 0x0190
+
/* Common MSI config fields */
#define MSI_CFG0_ADDR_MASK GENMASK_ULL(51, 2)
#define MSI_CFG2_SH GENMASK(5, 4)
@@ -669,6 +678,17 @@ struct arm_smmu_device {
struct arm_smmu_strtab_cfg strtab_cfg;
+ /* SMMU feature registers */
+ u32 idr0;
+ u32 idr1;
+ u32 idr2;
+ u32 idr3;
+ u32 idr4;
+ u32 idr5;
+ u32 idr6;
+ u32 iidr;
+ u32 aidr;
+
/* IOMMU core code handle */
struct iommu_device iommu;
@@ -676,6 +696,13 @@ struct arm_smmu_device {
struct mutex streams_mutex;
};
+static inline struct arm_smmu_device *dev_to_arm_smmu_device(struct device *dev)
+{
+ struct iommu_device *iommu = dev_to_iommu_device(dev);
+
+ return container_of(iommu, struct arm_smmu_device, iommu);
+}
+
struct arm_smmu_stream {
u32 id;
struct arm_smmu_master *master;