dmanegine: idxd: add debugfs for event log dump

Add debugfs entry to dump the content of the event log for debugging. The
function will dump all non-zero entries in the event log. It will note
which entries are processed and which entries are still pending processing
at the time of the dump. The entries may not always be in chronological
order due to the log is a circular buffer.

Tested-by: Tony Zhu <tony.zhu@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20230407203143.2189681-6-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

4 files changed, 160 insertions, 1 deletions

diff --git a/drivers/dma/idxd/Makefile b/drivers/dma/idxd/Makefile
index a1e9f2b3a37c..dc096839ac63 100644
--- a/drivers/dma/idxd/Makefile
+++ b/drivers/dma/idxd/Makefile
@@ -1,7 +1,7 @@
 ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=IDXD
 
 obj-$(CONFIG_INTEL_IDXD) += idxd.o
-idxd-y := init.o irq.o device.o sysfs.o submit.o dma.o cdev.o
+idxd-y := init.o irq.o device.o sysfs.o submit.o dma.o cdev.o debugfs.o
 
 idxd-$(CONFIG_INTEL_IDXD_PERFMON) += perfmon.o
 
diff --git a/drivers/dma/idxd/debugfs.c b/drivers/dma/idxd/debugfs.c
new file mode 100644
index 000000000000..9cfbd9b14c4c
--- /dev/null
+++ b/drivers/dma/idxd/debugfs.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2021 Intel Corporation. All rights rsvd. */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/debugfs.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <uapi/linux/idxd.h>
+#include "idxd.h"
+#include "registers.h"
+
+static struct dentry *idxd_debugfs_dir;
+
+static void dump_event_entry(struct idxd_device *idxd, struct seq_file *s,
+			     u16 index, int *count, bool processed)
+{
+	struct idxd_evl *evl = idxd->evl;
+	struct dsa_evl_entry *entry;
+	struct dsa_completion_record *cr;
+	u64 *raw;
+	int i;
+	int evl_strides = evl_ent_size(idxd) / sizeof(u64);
+
+	entry = (struct dsa_evl_entry *)evl->log + index;
+
+	if (!entry->e.desc_valid)
+		return;
+
+	seq_printf(s, "Event Log entry %d (real index %u) processed: %u\n",
+		   *count, index, processed);
+
+	seq_printf(s, "desc valid %u wq idx valid %u\n"
+		   "batch %u fault rw %u priv %u error 0x%x\n"
+		   "wq idx %u op %#x pasid %u batch idx %u\n"
+		   "fault addr %#llx\n",
+		   entry->e.desc_valid, entry->e.wq_idx_valid,
+		   entry->e.batch, entry->e.fault_rw, entry->e.priv,
+		   entry->e.error, entry->e.wq_idx, entry->e.operation,
+		   entry->e.pasid, entry->e.batch_idx, entry->e.fault_addr);
+
+	cr = &entry->cr;
+	seq_printf(s, "status %#x result %#x fault_info %#x bytes_completed %u\n"
+		   "fault addr %#llx inv flags %#x\n\n",
+		   cr->status, cr->result, cr->fault_info, cr->bytes_completed,
+		   cr->fault_addr, cr->invalid_flags);
+
+	raw = (u64 *)entry;
+
+	for (i = 0; i < evl_strides; i++)
+		seq_printf(s, "entry[%d] = %#llx\n", i, raw[i]);
+
+	seq_puts(s, "\n");
+	*count += 1;
+}
+
+static int debugfs_evl_show(struct seq_file *s, void *d)
+{
+	struct idxd_device *idxd = s->private;
+	struct idxd_evl *evl = idxd->evl;
+	union evl_status_reg evl_status;
+	u16 h, t, evl_size, i;
+	int count = 0;
+	bool processed = true;
+
+	if (!evl || !evl->log)
+		return 0;
+
+	spin_lock(&evl->lock);
+
+	h = evl->head;
+	evl_status.bits = ioread64(idxd->reg_base + IDXD_EVLSTATUS_OFFSET);
+	t = evl_status.tail;
+	evl_size = evl->size;
+
+	seq_printf(s, "Event Log head %u tail %u interrupt pending %u\n\n",
+		   evl_status.head, evl_status.tail, evl_status.int_pending);
+
+	i = t;
+	while (1) {
+		i = (i + 1) % evl_size;
+		if (i == t)
+			break;
+
+		if (processed && i == h)
+			processed = false;
+		dump_event_entry(idxd, s, i, &count, processed);
+	}
+
+	spin_unlock(&evl->lock);
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(debugfs_evl);
+
+int idxd_device_init_debugfs(struct idxd_device *idxd)
+{
+	if (IS_ERR_OR_NULL(idxd_debugfs_dir))
+		return 0;
+
+	idxd->dbgfs_dir = debugfs_create_dir(dev_name(idxd_confdev(idxd)), idxd_debugfs_dir);
+	if (IS_ERR(idxd->dbgfs_dir))
+		return PTR_ERR(idxd->dbgfs_dir);
+
+	if (idxd->evl) {
+		idxd->dbgfs_evl_file = debugfs_create_file("event_log", 0400,
+							   idxd->dbgfs_dir, idxd,
+							   &debugfs_evl_fops);
+		if (IS_ERR(idxd->dbgfs_evl_file)) {
+			debugfs_remove_recursive(idxd->dbgfs_dir);
+			idxd->dbgfs_dir = NULL;
+			return PTR_ERR(idxd->dbgfs_evl_file);
+		}
+	}
+
+	return 0;
+}
+
+void idxd_device_remove_debugfs(struct idxd_device *idxd)
+{
+	debugfs_remove_recursive(idxd->dbgfs_dir);
+}
+
+int idxd_init_debugfs(void)
+{
+	if (!debugfs_initialized())
+		return 0;
+
+	idxd_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
+	if (IS_ERR(idxd_debugfs_dir))
+		return  PTR_ERR(idxd_debugfs_dir);
+	return 0;
+}
+
+void idxd_remove_debugfs(void)
+{
+	debugfs_remove_recursive(idxd_debugfs_dir);
+}
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index c74681f02b18..b923b90b7299 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -330,6 +330,9 @@ struct idxd_device {
 
 	unsigned long *opcap_bmap;
 	struct idxd_evl *evl;
+
+	struct dentry *dbgfs_dir;
+	struct dentry *dbgfs_evl_file;
 };
 
 static inline unsigned int evl_ent_size(struct idxd_device *idxd)
@@ -704,4 +707,10 @@ static inline void perfmon_init(void) {}
 static inline void perfmon_exit(void) {}
 #endif
 
+/* debugfs */
+int idxd_device_init_debugfs(struct idxd_device *idxd);
+void idxd_device_remove_debugfs(struct idxd_device *idxd);
+int idxd_init_debugfs(void);
+void idxd_remove_debugfs(void);
+
 #endif
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index f44719a11c95..e21c4b7a1d32 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -669,6 +669,10 @@ static int idxd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		goto err_dev_register;
 	}
 
+	rc = idxd_device_init_debugfs(idxd);
+	if (rc)
+		dev_warn(dev, "IDXD debugfs failed to setup\n");
+
 	dev_info(&pdev->dev, "Intel(R) Accelerator Device (v%x)\n",
 		 idxd->hw.version);
 
@@ -731,6 +735,7 @@ static void idxd_remove(struct pci_dev *pdev)
 	idxd_shutdown(pdev);
 	if (device_pasid_enabled(idxd))
 		idxd_disable_system_pasid(idxd);
+	idxd_device_remove_debugfs(idxd);
 
 	irq_entry = idxd_get_ie(idxd, 0);
 	free_irq(irq_entry->vector, irq_entry);
@@ -788,6 +793,10 @@ static int __init idxd_init_module(void)
 	if (err)
 		goto err_cdev_register;
 
+	err = idxd_init_debugfs();
+	if (err)
+		goto err_debugfs;
+
 	err = pci_register_driver(&idxd_pci_driver);
 	if (err)
 		goto err_pci_register;
@@ -795,6 +804,8 @@ static int __init idxd_init_module(void)
 	return 0;
 
 err_pci_register:
+	idxd_remove_debugfs();
+err_debugfs:
 	idxd_cdev_remove();
 err_cdev_register:
 	idxd_driver_unregister(&idxd_user_drv);
@@ -815,5 +826,6 @@ static void __exit idxd_exit_module(void)
 	pci_unregister_driver(&idxd_pci_driver);
 	idxd_cdev_remove();
 	perfmon_exit();
+	idxd_remove_debugfs();
 }
 module_exit(idxd_exit_module);