[PATCH v2 2/2] iommu/amd: Add basic debugfs infrastructure for AMD IOMMU

[Gary R Hook]

Implement a skeleton framework for debugfs support in the
AMD IOMMU.

Signed-off-by: Gary R Hook <gary.h...@amd.com>
---
 drivers/iommu/Makefile            |    1 +
 drivers/iommu/amd_iommu_debugfs.c |   45 +++++++++++++++++++++++++++++++++++++
 drivers/iommu/amd_iommu_init.c    |    7 ++++--
 drivers/iommu/amd_iommu_proto.h   |    8 ++++++-
 drivers/iommu/amd_iommu_types.h   |    3 ++
 5 files changed, 61 insertions(+), 3 deletions(-)
 create mode 100644 drivers/iommu/amd_iommu_debugfs.c

diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 5eb1121d54b9..0ca250f626d9 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_IOMMU_IOVA) += iova.o
 obj-$(CONFIG_OF_IOMMU) += of_iommu.o
 obj-$(CONFIG_MSM_IOMMU) += msm_iommu.o
 obj-$(CONFIG_AMD_IOMMU) += amd_iommu.o amd_iommu_init.o
+obj-$(CONFIG_IOMMU_DEBUG) += amd_iommu_debugfs.o
 obj-$(CONFIG_AMD_IOMMU_V2) += amd_iommu_v2.o
 obj-$(CONFIG_ARM_SMMU) += arm-smmu.o
 obj-$(CONFIG_ARM_SMMU_V3) += arm-smmu-v3.o
diff --git a/drivers/iommu/amd_iommu_debugfs.c 
b/drivers/iommu/amd_iommu_debugfs.c
new file mode 100644
index 000000000000..282100a655b3
--- /dev/null
+++ b/drivers/iommu/amd_iommu_debugfs.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD IOMMU driver
+ *
+ * Copyright (C) 2018 Advanced Micro Devices, Inc.
+ *
+ * Author: Gary R Hook <gary.h...@amd.com>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/iommu.h>
+#include <linux/pci.h>
+#include "amd_iommu_proto.h"
+#include "amd_iommu_types.h"
+
+static struct dentry *amd_iommu_debugfs;
+static DEFINE_MUTEX(amd_iommu_debugfs_lock);
+
+#define        MAX_NAME_LEN    20
+
+void amd_iommu_debugfs_setup(struct amd_iommu *iommu)
+{
+       char name[MAX_NAME_LEN + 1];
+       struct dentry *d_top;
+
+       if (!debugfs_initialized())
+               return;
+
+       mutex_lock(&amd_iommu_debugfs_lock);
+       if (!amd_iommu_debugfs) {
+               d_top = iommu_debugfs_setup();
+               if (d_top)
+                       amd_iommu_debugfs = debugfs_create_dir("amd", d_top);
+       }
+       mutex_unlock(&amd_iommu_debugfs_lock);
+       if (amd_iommu_debugfs) {
+               snprintf(name, MAX_NAME_LEN, "iommu%02d", iommu->index);
+               iommu->debugfs = debugfs_create_dir(name,
+                                                   amd_iommu_debugfs);
+               if (!iommu->debugfs) {
+                       debugfs_remove_recursive(amd_iommu_debugfs);
+                       amd_iommu_debugfs = NULL;
+               }
+       }
+}
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 6fe2d0346073..43856c7f4ea1 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -89,6 +89,7 @@
 #define ACPI_DEVFLAG_ATSDIS             0x10000000
 
 #define LOOP_TIMEOUT   100000
+
 /*
  * ACPI table definitions
  *
@@ -2720,6 +2721,7 @@ int __init amd_iommu_enable_faulting(void)
  */
 static int __init amd_iommu_init(void)
 {
+       struct amd_iommu *iommu;
        int ret;
 
        ret = iommu_go_to_state(IOMMU_INITIALIZED);
@@ -2729,14 +2731,15 @@ static int __init amd_iommu_init(void)
                        disable_iommus();
                        free_iommu_resources();
                } else {
-                       struct amd_iommu *iommu;
-
                        uninit_device_table_dma();
                        for_each_iommu(iommu)
                                iommu_flush_all_caches(iommu);
                }
        }
 
+       for_each_iommu(iommu)
+               amd_iommu_debugfs_setup(iommu);
+
        return ret;
 }
 
diff --git a/drivers/iommu/amd_iommu_proto.h b/drivers/iommu/amd_iommu_proto.h
index 640c286a0ab9..1cfaae28c2cd 100644
--- a/drivers/iommu/amd_iommu_proto.h
+++ b/drivers/iommu/amd_iommu_proto.h
@@ -33,6 +33,12 @@ extern void amd_iommu_uninit_devices(void);
 extern void amd_iommu_init_notifier(void);
 extern int amd_iommu_init_api(void);
 
+#ifdef CONFIG_IOMMU_DEBUG
+void amd_iommu_debugfs_setup(struct amd_iommu *iommu);
+#else
+static inline void amd_iommu_debugfs_setup(struct amd_iommu *iommu) {}
+#endif
+
 /* Needed for interrupt remapping */
 extern int amd_iommu_prepare(void);
 extern int amd_iommu_enable(void);
@@ -58,7 +64,7 @@ extern int amd_iommu_domain_clear_gcr3(struct iommu_domain 
*dom, int pasid);
 extern struct iommu_domain *amd_iommu_get_v2_domain(struct pci_dev *pdev);
 
 #ifdef CONFIG_IRQ_REMAP
-extern int amd_iommu_create_irq_domain(struct amd_iommu *iommu);
+int amd_iommu_create_irq_domain(struct amd_iommu *iommu);
 #else
 static inline int amd_iommu_create_irq_domain(struct amd_iommu *iommu)
 {
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index f6b24c7d8b70..43c52797810e 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -591,6 +591,9 @@ struct amd_iommu {
 
        u32 flags;
        volatile u64 __aligned(8) cmd_sem;
+
+       /* DebugFS Info */
+       struct dentry *debugfs;
 };
 
 static inline struct amd_iommu *dev_to_amd_iommu(struct device *dev)

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