Re: [PATCH RESEND v2 4/5] iommu/tegra-smmu: Rework tegra_smmu_probe_device()

[Nicolin Chen <nicoleotsuka@gmail.com>]

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Hi Guillaume,

On Thu, Feb 04, 2021 at 09:24:23PM -0800, Nicolin Chen wrote:
> > Please let us know if you need any help debugging this issue or
> > to try a fix on this platform.
> 
> Yes, I don't have any Tegra124 platform to run. It'd be very nice
> if you can run some debugging patch (I can provide you) and a fix
> after I root cause the issue.

Would it be possible for you to run with the given debugging patch?

It'd be nicer if I can get both logs of the vanilla kernel (failing)
and the commit-reverted version (passing), each applying this patch.

Thanks in advance!
Nicolin

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From 80f288d7101101fca0412c5c200cea7e203a675d Mon Sep 17 00:00:00 2001
From: Nicolin Chen <nicoleotsuka@gmail.com>
Date: Fri, 5 Feb 2021 01:41:07 -0800
Subject: [PATCH] iommu: debug tegra-smmu

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
 drivers/iommu/tegra-smmu.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 4a3f095a1c26..796b7df54b8f 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -363,6 +363,7 @@ static void tegra_smmu_enable(struct tegra_smmu *smmu, unsigned int swgroup,
 		value |= SMMU_ASID_VALUE(asid);
 		value |= SMMU_ASID_ENABLE;
 		smmu_writel(smmu, value, group->reg);
+		pr_alert("--------%s, swgroup %d: writing %x to reg1 %x\n", __func__, swgroup, value, group->reg);
 	} else {
 		pr_warn("%s group from swgroup %u not found\n", __func__,
 				swgroup);
@@ -379,6 +380,7 @@ static void tegra_smmu_enable(struct tegra_smmu *smmu, unsigned int swgroup,
 		value = smmu_readl(smmu, client->smmu.reg);
 		value |= BIT(client->smmu.bit);
 		smmu_writel(smmu, value, client->smmu.reg);
+		pr_alert("--------%s, swgroup %d: writing %x to reg2 %x\n", __func__, swgroup, value, client->smmu.reg);
 	}
 }
 
@@ -491,13 +493,19 @@ static int tegra_smmu_attach_dev(struct iommu_domain *domain,
 	unsigned int index;
 	int err;
 
+	dev_alert(dev, "-------%s: smmu %s\n", __func__, smmu ? "valid" : "NULL");
+	dump_stack();
 	if (!fwspec)
 		return -ENOENT;
 
+	dev_alert(dev, "-------%s: fwspec->num_ids %d\n", __func__, fwspec->num_ids);
 	for (index = 0; index < fwspec->num_ids; index++) {
 		err = tegra_smmu_as_prepare(smmu, as);
-		if (err)
+		if (err) {
+			dev_err(dev, "failed to prepare as(%d) for fwspec %d",
+				as->id, fwspec->ids[index]);
 			goto disable;
+		}
 
 		tegra_smmu_enable(smmu, fwspec->ids[index], as->id);
 	}
@@ -805,6 +813,8 @@ static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
 	if (!smmu)
 		return ERR_PTR(-ENODEV);
 
+	dev_alert(dev, "--------%s, %d\n", __func__, __LINE__);
+	dump_stack();
 	return &smmu->iommu;
 }
 
@@ -904,6 +914,8 @@ static int tegra_smmu_of_xlate(struct device *dev,
 
 	dev_iommu_priv_set(dev, mc->smmu);
 
+	dev_alert(dev, "-------%s: id %d", __func__, id);
+	dump_stack();
 	return iommu_fwspec_add_ids(dev, &id, 1);
 }
 
-- 
2.17.1