diff mbox series

[PATCHv2] iommu/arm-smmu-qcom: Add debug support for TLB sync timeouts

Message ID 20220526041403.9984-1-quic_saipraka@quicinc.com (mailing list archive)
State New, archived
Headers show
Series [PATCHv2] iommu/arm-smmu-qcom: Add debug support for TLB sync timeouts | expand

Commit Message

Sai Prakash Ranjan May 26, 2022, 4:14 a.m. UTC
TLB sync timeouts can be due to various reasons such as TBU power down
or pending TCU/TBU invalidation/sync and so on. Debugging these often
require dumping of some implementation defined registers to know the
status of TBU/TCU operations and some of these registers are not
accessible in non-secure world such as from kernel and requires SMC
calls to read them in the secure world. So, add this debug support
to dump implementation defined registers for TLB sync timeout issues.

Signed-off-by: Sai Prakash Ranjan <quic_saipraka@quicinc.com>
---

Changes in v2:
 * Use scm call consistently so that it works on older chipsets where
   some of these regs are secure registers.
 * Add device specific data to get the implementation defined register
   offsets.

---
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 161 ++++++++++++++++++---
 drivers/iommu/arm/arm-smmu/arm-smmu.c      |   2 +
 drivers/iommu/arm/arm-smmu/arm-smmu.h      |   1 +
 3 files changed, 146 insertions(+), 18 deletions(-)

Comments

Vincent Knecht June 8, 2022, 9:22 p.m. UTC | #1
Le jeudi 26 mai 2022 à 09:44 +0530, Sai Prakash Ranjan a écrit :
> TLB sync timeouts can be due to various reasons such as TBU power down
> or pending TCU/TBU invalidation/sync and so on. Debugging these often
> require dumping of some implementation defined registers to know the
> status of TBU/TCU operations and some of these registers are not
> accessible in non-secure world such as from kernel and requires SMC
> calls to read them in the secure world. So, add this debug support
> to dump implementation defined registers for TLB sync timeout issues.
> 
> Signed-off-by: Sai Prakash Ranjan <quic_saipraka@quicinc.com>
> ---
> 
> Changes in v2:
>  * Use scm call consistently so that it works on older chipsets where
>    some of these regs are secure registers.
>  * Add device specific data to get the implementation defined register
>    offsets.
> 
> ---
>  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 161 ++++++++++++++++++---
>  drivers/iommu/arm/arm-smmu/arm-smmu.c      |   2 +
>  drivers/iommu/arm/arm-smmu/arm-smmu.h      |   1 +
>  3 files changed, 146 insertions(+), 18 deletions(-)

Hi Sai, and thanks for this patch !

I've encountered TLB sync timeouts with msm8939 SoC recently.
What would be needed to add to this patch so this SoC is supported ?
Like, where could one check the values to be used in an equivalent
of qcom_smmu_impl0_reg_offset values for this SoC (if any change needed) ?
Current values are not found by simply greping in downstream/vendor dtsi/dts files...
Sai Prakash Ranjan June 9, 2022, 8 a.m. UTC | #2
Hi Vincent,

On 6/9/2022 2:52 AM, Vincent Knecht wrote:
> Le jeudi 26 mai 2022 à 09:44 +0530, Sai Prakash Ranjan a écrit :
>> TLB sync timeouts can be due to various reasons such as TBU power down
>> or pending TCU/TBU invalidation/sync and so on. Debugging these often
>> require dumping of some implementation defined registers to know the
>> status of TBU/TCU operations and some of these registers are not
>> accessible in non-secure world such as from kernel and requires SMC
>> calls to read them in the secure world. So, add this debug support
>> to dump implementation defined registers for TLB sync timeout issues.
>>
>> Signed-off-by: Sai Prakash Ranjan <quic_saipraka@quicinc.com>
>> ---
>>
>> Changes in v2:
>>   * Use scm call consistently so that it works on older chipsets where
>>     some of these regs are secure registers.
>>   * Add device specific data to get the implementation defined register
>>     offsets.
>>
>> ---
>>   drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 161 ++++++++++++++++++---
>>   drivers/iommu/arm/arm-smmu/arm-smmu.c      |   2 +
>>   drivers/iommu/arm/arm-smmu/arm-smmu.h      |   1 +
>>   3 files changed, 146 insertions(+), 18 deletions(-)
> Hi Sai, and thanks for this patch !
>
> I've encountered TLB sync timeouts with msm8939 SoC recently.
> What would be needed to add to this patch so this SoC is supported ?
> Like, where could one check the values to be used in an equivalent
> of qcom_smmu_impl0_reg_offset values for this SoC (if any change needed) ?
> Current values are not found by simply greping in downstream/vendor dtsi/dts files...

These are implementation defined registers and some might not be present on older SoCs
and sometimes they don't add this support in downstream kernels even if the registers
are present.

I looked up the IP doc for msm8939 and I could find only TBU_PWR_STATUS register and
you can use the same offset for it as given in this patch.

Thanks,
Sai
Sai Prakash Ranjan June 23, 2022, 6:02 a.m. UTC | #3
On 5/26/2022 9:44 AM, Sai Prakash Ranjan wrote:
> TLB sync timeouts can be due to various reasons such as TBU power down
> or pending TCU/TBU invalidation/sync and so on. Debugging these often
> require dumping of some implementation defined registers to know the
> status of TBU/TCU operations and some of these registers are not
> accessible in non-secure world such as from kernel and requires SMC
> calls to read them in the secure world. So, add this debug support
> to dump implementation defined registers for TLB sync timeout issues.
>
> Signed-off-by: Sai Prakash Ranjan <quic_saipraka@quicinc.com>
> ---
>
> Changes in v2:
>   * Use scm call consistently so that it works on older chipsets where
>     some of these regs are secure registers.
>   * Add device specific data to get the implementation defined register
>     offsets.
>
> ---
>   drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 161 ++++++++++++++++++---
>   drivers/iommu/arm/arm-smmu/arm-smmu.c      |   2 +
>   drivers/iommu/arm/arm-smmu/arm-smmu.h      |   1 +
>   3 files changed, 146 insertions(+), 18 deletions(-)

Any comments on this patch?

Thanks,
Sai
diff mbox series

Patch

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 7820711c4560..bb68aa85b28b 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -5,13 +5,27 @@ 
 
 #include <linux/acpi.h>
 #include <linux/adreno-smmu-priv.h>
+#include <linux/delay.h>
 #include <linux/of_device.h>
 #include <linux/qcom_scm.h>
 
 #include "arm-smmu.h"
 
+#define QCOM_DUMMY_VAL	-1
+
+enum qcom_smmu_impl_reg_offset {
+	QCOM_SMMU_TBU_PWR_STATUS,
+	QCOM_SMMU_STATS_SYNC_INV_TBU_ACK,
+	QCOM_SMMU_MMU2QSS_AND_SAFE_WAIT_CNTR,
+};
+
+struct qcom_smmu_config {
+	const u32 *reg_offset;
+};
+
 struct qcom_smmu {
 	struct arm_smmu_device smmu;
+	const struct qcom_smmu_config *cfg;
 	bool bypass_quirk;
 	u8 bypass_cbndx;
 	u32 stall_enabled;
@@ -22,6 +36,56 @@  static struct qcom_smmu *to_qcom_smmu(struct arm_smmu_device *smmu)
 	return container_of(smmu, struct qcom_smmu, smmu);
 }
 
+static void qcom_smmu_tlb_sync(struct arm_smmu_device *smmu, int page,
+				int sync, int status)
+{
+	int ret;
+	unsigned int spin_cnt, delay;
+	u32 reg, tbu_pwr_status, sync_inv_ack, sync_inv_progress;
+	struct qcom_smmu *qsmmu = to_qcom_smmu(smmu);
+	const struct qcom_smmu_config *cfg;
+
+	arm_smmu_writel(smmu, page, sync, QCOM_DUMMY_VAL);
+	for (delay = 1; delay < TLB_LOOP_TIMEOUT; delay *= 2) {
+		for (spin_cnt = TLB_SPIN_COUNT; spin_cnt > 0; spin_cnt--) {
+			reg = arm_smmu_readl(smmu, page, status);
+			if (!(reg & ARM_SMMU_sTLBGSTATUS_GSACTIVE))
+				return;
+			cpu_relax();
+		}
+		udelay(delay);
+	}
+
+	dev_err_ratelimited(smmu->dev,
+			    "TLB sync timed out -- SMMU may be deadlocked\n");
+
+	cfg = qsmmu->cfg;
+	if (!cfg)
+		return;
+
+	ret = qcom_scm_io_readl(smmu->ioaddr + cfg->reg_offset[QCOM_SMMU_TBU_PWR_STATUS],
+				&tbu_pwr_status);
+	if (ret)
+		dev_err_ratelimited(smmu->dev,
+				    "Failed to read TBU power status: %d\n", ret);
+
+	ret = qcom_scm_io_readl(smmu->ioaddr + cfg->reg_offset[QCOM_SMMU_STATS_SYNC_INV_TBU_ACK],
+				&sync_inv_ack);
+	if (ret)
+		dev_err_ratelimited(smmu->dev,
+				    "Failed to read TBU sync/inv ack status: %d\n", ret);
+
+	ret = qcom_scm_io_readl(smmu->ioaddr + cfg->reg_offset[QCOM_SMMU_MMU2QSS_AND_SAFE_WAIT_CNTR],
+				&sync_inv_progress);
+	if (ret)
+		dev_err_ratelimited(smmu->dev,
+				    "Failed to read TCU syn/inv progress: %d\n", ret);
+
+	dev_err_ratelimited(smmu->dev,
+			    "TBU: power_status %#x sync_inv_ack %#x sync_inv_progress %#x\n",
+			    tbu_pwr_status, sync_inv_ack, sync_inv_progress);
+}
+
 static void qcom_adreno_smmu_write_sctlr(struct arm_smmu_device *smmu, int idx,
 		u32 reg)
 {
@@ -374,6 +438,7 @@  static const struct arm_smmu_impl qcom_smmu_impl = {
 	.def_domain_type = qcom_smmu_def_domain_type,
 	.reset = qcom_smmu500_reset,
 	.write_s2cr = qcom_smmu_write_s2cr,
+	.tlb_sync = qcom_smmu_tlb_sync,
 };
 
 static const struct arm_smmu_impl qcom_adreno_smmu_impl = {
@@ -382,12 +447,84 @@  static const struct arm_smmu_impl qcom_adreno_smmu_impl = {
 	.reset = qcom_smmu500_reset,
 	.alloc_context_bank = qcom_adreno_smmu_alloc_context_bank,
 	.write_sctlr = qcom_adreno_smmu_write_sctlr,
+	.tlb_sync = qcom_smmu_tlb_sync,
+};
+
+/* Implementation Defined Register Space 0 register offsets */
+static const u32 qcom_smmu_impl0_reg_offset[] = {
+	[QCOM_SMMU_TBU_PWR_STATUS]		= 0x2204,
+	[QCOM_SMMU_STATS_SYNC_INV_TBU_ACK]	= 0x25dc,
+	[QCOM_SMMU_MMU2QSS_AND_SAFE_WAIT_CNTR]	= 0x2670,
+};
+
+static const struct qcom_smmu_config qcm2290_smmu_cfg = {
+	.reg_offset = qcom_smmu_impl0_reg_offset,
+};
+
+static const struct qcom_smmu_config sc7180_smmu_cfg = {
+	.reg_offset = qcom_smmu_impl0_reg_offset,
+};
+
+static const struct qcom_smmu_config sc7280_smmu_cfg = {
+	.reg_offset = qcom_smmu_impl0_reg_offset,
+};
+
+static const struct qcom_smmu_config sc8180x_smmu_cfg = {
+	.reg_offset = qcom_smmu_impl0_reg_offset,
+};
+
+static const struct qcom_smmu_config sc8280xp_smmu_cfg = {
+	.reg_offset = qcom_smmu_impl0_reg_offset,
+};
+
+static const struct qcom_smmu_config sm6125_smmu_cfg = {
+	.reg_offset = qcom_smmu_impl0_reg_offset,
+};
+
+static const struct qcom_smmu_config sm6350_smmu_cfg = {
+	.reg_offset = qcom_smmu_impl0_reg_offset,
+};
+
+static const struct qcom_smmu_config sm8150_smmu_cfg = {
+	.reg_offset = qcom_smmu_impl0_reg_offset,
+};
+
+static const struct qcom_smmu_config sm8250_smmu_cfg = {
+	.reg_offset = qcom_smmu_impl0_reg_offset,
+};
+
+static const struct qcom_smmu_config sm8350_smmu_cfg = {
+	.reg_offset = qcom_smmu_impl0_reg_offset,
+};
+
+static const struct qcom_smmu_config sm8450_smmu_cfg = {
+	.reg_offset = qcom_smmu_impl0_reg_offset,
+};
+
+static const struct of_device_id __maybe_unused qcom_smmu_impl_of_match[] = {
+	{ .compatible = "qcom,msm8998-smmu-v2" },
+	{ .compatible = "qcom,qcm2290-smmu-500", .data = &qcm2290_smmu_cfg },
+	{ .compatible = "qcom,sc7180-smmu-500", .data = &sc7180_smmu_cfg },
+	{ .compatible = "qcom,sc7280-smmu-500", .data = &sc7280_smmu_cfg},
+	{ .compatible = "qcom,sc8180x-smmu-500", .data = &sc8180x_smmu_cfg },
+	{ .compatible = "qcom,sc8280xp-smmu-500", .data = &sc8280xp_smmu_cfg },
+	{ .compatible = "qcom,sdm630-smmu-v2" },
+	{ .compatible = "qcom,sdm845-smmu-500" },
+	{ .compatible = "qcom,sm6125-smmu-500", .data = &sm6125_smmu_cfg},
+	{ .compatible = "qcom,sm6350-smmu-500", .data = &sm6350_smmu_cfg},
+	{ .compatible = "qcom,sm8150-smmu-500", .data = &sm8150_smmu_cfg },
+	{ .compatible = "qcom,sm8250-smmu-500", .data = &sm8250_smmu_cfg },
+	{ .compatible = "qcom,sm8350-smmu-500", .data = &sm8350_smmu_cfg },
+	{ .compatible = "qcom,sm8450-smmu-500", .data = &sm8450_smmu_cfg },
+	{ }
 };
 
 static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,
 		const struct arm_smmu_impl *impl)
 {
 	struct qcom_smmu *qsmmu;
+	const struct of_device_id *match;
+	const struct device_node *np = smmu->dev->of_node;
 
 	/* Check to make sure qcom_scm has finished probing */
 	if (!qcom_scm_is_available())
@@ -398,28 +535,16 @@  static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,
 		return ERR_PTR(-ENOMEM);
 
 	qsmmu->smmu.impl = impl;
+	match = of_match_node(qcom_smmu_impl_of_match, np);
+	if (!match)
+		goto out;
+
+	qsmmu->cfg = match->data;
 
+out:
 	return &qsmmu->smmu;
 }
 
-static const struct of_device_id __maybe_unused qcom_smmu_impl_of_match[] = {
-	{ .compatible = "qcom,msm8998-smmu-v2" },
-	{ .compatible = "qcom,qcm2290-smmu-500" },
-	{ .compatible = "qcom,sc7180-smmu-500" },
-	{ .compatible = "qcom,sc7280-smmu-500" },
-	{ .compatible = "qcom,sc8180x-smmu-500" },
-	{ .compatible = "qcom,sc8280xp-smmu-500" },
-	{ .compatible = "qcom,sdm630-smmu-v2" },
-	{ .compatible = "qcom,sdm845-smmu-500" },
-	{ .compatible = "qcom,sm6125-smmu-500" },
-	{ .compatible = "qcom,sm6350-smmu-500" },
-	{ .compatible = "qcom,sm8150-smmu-500" },
-	{ .compatible = "qcom,sm8250-smmu-500" },
-	{ .compatible = "qcom,sm8350-smmu-500" },
-	{ .compatible = "qcom,sm8450-smmu-500" },
-	{ }
-};
-
 #ifdef CONFIG_ACPI
 static struct acpi_platform_list qcom_acpi_platlist[] = {
 	{ "LENOVO", "CB-01   ", 0x8180, ACPI_SIG_IORT, equal, "QCOM SMMU" },
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 2ed3594f384e..4c5b51109835 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -2099,6 +2099,8 @@  static int arm_smmu_device_probe(struct platform_device *pdev)
 	if (IS_ERR(smmu->base))
 		return PTR_ERR(smmu->base);
 	ioaddr = res->start;
+	smmu->ioaddr = ioaddr;
+
 	/*
 	 * The resource size should effectively match the value of SMMU_TOP;
 	 * stash that temporarily until we know PAGESIZE to validate it with.
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h
index 2b9b42fb6f30..703fd5817ec1 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
@@ -278,6 +278,7 @@  struct arm_smmu_device {
 	struct device			*dev;
 
 	void __iomem			*base;
+	phys_addr_t			ioaddr;
 	unsigned int			numpage;
 	unsigned int			pgshift;