Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: [PATCH 2/2] iommu/amd: Add basic debugfs infrastructure for AMD
 IOMMU
From:   Gary R Hook <gary.hook@amd.com>
To:     iommu@lists.linux-foundation.org
Cc:     joro@8bytes.org, jacob.jun.pan@linux.intel.com,
        linux-kernel@vger.kernel.org
Date:   Thu, 29 Mar 2018 17:54:54 -0500
Message-ID: <152236409481.3266.6464716993249076762.stgit@taos>
In-Reply-To: <152236384612.3266.1451709369164076985.stgit@taos>
References: <152236384612.3266.1451709369164076985.stgit@taos>
User-Agent: StGit/0.17.1-dirty
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Received-SPF: None (protection.outlook.com: amd.com does not designate
 permitted sender hosts)
SpamDiagnosticOutput: 1:99
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Mar 2018 22:54:59.6153 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 7e970eb1-99e6-4b53-ef88-08d595c81a1f
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BLUPR12MB0691
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

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


Signed-off-by: Gary R Hook <gary.hook@amd.com>
---
 drivers/iommu/Kconfig             |    6 ++---
 drivers/iommu/Makefile            |    2 +-
 drivers/iommu/amd_iommu_debugfs.c |   47 +++++++++++++++++++++++++++++++++++++
 drivers/iommu/amd_iommu_init.c    |    9 ++++---
 drivers/iommu/amd_iommu_proto.h   |    6 +++++
 drivers/iommu/amd_iommu_types.h   |    3 ++
 include/linux/iommu.h             |    8 +++---
 7 files changed, 69 insertions(+), 12 deletions(-)
 create mode 100644 drivers/iommu/amd_iommu_debugfs.c

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index d40248446214..8d50151d5bf4 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -65,9 +65,9 @@ config IOMMU_DEBUG
 	depends on DEBUG_FS
 	default n
 	help
-	  Base enablement for access to any IOMMU device. Allows individual
-	  drivers to populate debugfs for access to IOMMU registers and
-	  data structures.
+	  Enable exposure of IOMMU device internals. Allow devices to
+	  populate debugfs for access to IOMMU registers and data
+	  structures.
 
 config IOMMU_IOVA
 	tristate
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 5e5c3339681d..0ca250f626d9 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -11,7 +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-$(CONFIG_AMD_IOMMU_DEBUG) += amd_iommu_debugfs.o
+obj-$(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..3547ad3339c1
--- /dev/null
+++ b/drivers/iommu/amd_iommu_debugfs.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD IOMMU driver
+ *
+ * Copyright (C) 2018 Advanced Micro Devices, Inc.
+ *
+ * Author: Gary R Hook <gary.hook@amd.com>
+ */
+
+#ifdef	CONFIG_IOMMU_DEBUG
+
+#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 *iommu_debugfs_dir;
+static DEFINE_RWLOCK(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;
+	unsigned long flags;
+
+	if (!debugfs_initialized())
+		return;
+
+	write_lock_irqsave(&iommu_debugfs_lock, flags);
+	if (!iommu_debugfs_dir && (d_top = iommu_debugfs_setup()))
+		iommu_debugfs_dir = debugfs_create_dir("amd", d_top);
+	write_unlock_irqrestore(&iommu_debugfs_lock, flags);
+	if (iommu_debugfs_dir) {
+		snprintf(name, MAX_NAME_LEN, "iommu%02d", iommu->index);
+		iommu->debugfs_instance = debugfs_create_dir(name,
+							     iommu_debugfs_dir);
+		if (!iommu->debugfs_instance)
+			debugfs_remove_recursive(iommu_debugfs_dir);
+	}
+
+	return;
+}
+
+#endif
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 99d48c42a12f..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;
 }
 
@@ -2783,8 +2786,6 @@ int __init amd_iommu_detect(void)
 	iommu_detected = 1;
 	x86_init.iommu.iommu_init = amd_iommu_init;
 
-dump_stack();
-
 	return 1;
 }
 
diff --git a/drivers/iommu/amd_iommu_proto.h b/drivers/iommu/amd_iommu_proto.h
index 640c286a0ab9..e19cebc5c740 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
+extern 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);
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index f6b24c7d8b70..6dca9fe38518 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_instance;
 };
 
 static inline struct amd_iommu *dev_to_amd_iommu(struct device *dev)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 98527f9b473b..dbfff811aa25 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -412,6 +412,10 @@ void iommu_fwspec_free(struct device *dev);
 int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids);
 const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode);
 
+#ifdef	CONFIG_IOMMU_DEBUG
+extern struct dentry *iommu_debugfs_setup(void);
+#endif
+
 #else /* CONFIG_IOMMU_API */
 
 struct iommu_ops {};
@@ -696,10 +700,6 @@ const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode)
 	return NULL;
 }
 
-#ifdef	CONFIG_IOMMU_DEBUG
-extern struct dentry *iommu_debugfs_setup(void);
-#endif
-
 #endif /* CONFIG_IOMMU_API */
 
 #endif /* __LINUX_IOMMU_H */