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>

1 files changed, 138 insertions, 0 deletions

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);
+}