scsi: mpt3sas: Capture IOC data for debugging purposes

Information needed to debug driver problems and firmware faults is stored
in the IOC’s MPT3SAS_ADAPTER data structure. Parameters such as IOCFacts,
IOC flags (related to sge, MSI-X, error recovery etc.), performance mode
type, TMs, internal commands reply status, etc. are present.

For debugging purposes, it is therefore helpful to be able to capture this
information so that the fault can be analyzed. Export the MPT3SAS_ADAPTER
data structure in debugfs. The data is available in:

	 /sys/kernel/debug/mpt3sas/scsi_hostX/ioc_dump

Link: https://lore.kernel.org/r/1588056322-29227-1-git-send-email-suganath-prabu.subramani@broadcom.com
Signed-off-by: Suganath Prabu <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 158 insertions, 0 deletions

diff --git a/drivers/scsi/mpt3sas/mpt3sas_debugfs.c b/drivers/scsi/mpt3sas/mpt3sas_debugfs.c
new file mode 100644
index 000000000000..48095d8aef95
--- /dev/null
+++ b/drivers/scsi/mpt3sas/mpt3sas_debugfs.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Debugfs interface Support for MPT (Message Passing Technology) based
+ * controllers.
+ *
+ * Copyright (C) 2020  Broadcom Inc.
+ *
+ * Authors: Broadcom Inc.
+ * Sreekanth Reddy  <sreekanth.reddy@broadcom.com>
+ * Suganath Prabu <suganath-prabu.subramani@broadcom.com>
+ *
+ * Send feedback to : MPT-FusionLinux.pdl@broadcom.com)
+ *
+ **/
+
+#include <linux/version.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <linux/compat.h>
+#include <linux/uio.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_host.h>
+#include "mpt3sas_base.h"
+#include <linux/debugfs.h>
+
+static struct dentry *mpt3sas_debugfs_root;
+
+/*
+ * _debugfs_iocdump_read - copy ioc dump from debugfs buffer
+ * @filep:	File Pointer
+ * @ubuf:	Buffer to fill data
+ * @cnt:	Length of the buffer
+ * @ppos:	Offset in the file
+ */
+
+static ssize_t
+_debugfs_iocdump_read(struct file *filp, char __user *ubuf, size_t cnt,
+	loff_t *ppos)
+
+{
+	struct mpt3sas_debugfs_buffer *debug = filp->private_data;
+
+	if (!debug || !debug->buf)
+		return 0;
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, debug->buf, debug->len);
+}
+
+/*
+ * _debugfs_iocdump_open :	open the ioc_dump debugfs attribute file
+ */
+static int
+_debugfs_iocdump_open(struct inode *inode, struct file *file)
+{
+	struct MPT3SAS_ADAPTER *ioc = inode->i_private;
+	struct mpt3sas_debugfs_buffer *debug;
+
+	debug = kzalloc(sizeof(struct mpt3sas_debugfs_buffer), GFP_KERNEL);
+	if (!debug)
+		return -ENOMEM;
+
+	debug->buf = (void *)ioc;
+	debug->len = sizeof(struct MPT3SAS_ADAPTER);
+	file->private_data = debug;
+	return 0;
+}
+
+/*
+ * _debugfs_iocdump_release :	release the ioc_dump debugfs attribute
+ * @inode: inode structure to the corresponds device
+ * @file: File pointer
+ */
+static int
+_debugfs_iocdump_release(struct inode *inode, struct file *file)
+{
+	struct mpt3sas_debugfs_buffer *debug = file->private_data;
+
+	if (!debug)
+		return 0;
+
+	file->private_data = NULL;
+	kfree(debug);
+	return 0;
+}
+
+static const struct file_operations mpt3sas_debugfs_iocdump_fops = {
+	.owner		= THIS_MODULE,
+	.open           = _debugfs_iocdump_open,
+	.read           = _debugfs_iocdump_read,
+	.release        = _debugfs_iocdump_release,
+};
+
+/*
+ * mpt3sas_init_debugfs :	Create debugfs root for mpt3sas driver
+ */
+void mpt3sas_init_debugfs(void)
+{
+	mpt3sas_debugfs_root = debugfs_create_dir("mpt3sas", NULL);
+	if (!mpt3sas_debugfs_root)
+		pr_info("mpt3sas: Cannot create debugfs root\n");
+}
+
+/*
+ * mpt3sas_exit_debugfs :	Remove debugfs root for mpt3sas driver
+ */
+void mpt3sas_exit_debugfs(void)
+{
+	debugfs_remove_recursive(mpt3sas_debugfs_root);
+}
+
+/*
+ * mpt3sas_setup_debugfs :	Setup debugfs per HBA adapter
+ * ioc:				MPT3SAS_ADAPTER object
+ */
+void
+mpt3sas_setup_debugfs(struct MPT3SAS_ADAPTER *ioc)
+{
+	char name[64];
+
+	snprintf(name, sizeof(name), "scsi_host%d", ioc->shost->host_no);
+	if (!ioc->debugfs_root) {
+		ioc->debugfs_root =
+		    debugfs_create_dir(name, mpt3sas_debugfs_root);
+		if (!ioc->debugfs_root) {
+			dev_err(&ioc->pdev->dev,
+			    "Cannot create per adapter debugfs directory\n");
+			return;
+		}
+	}
+
+	snprintf(name, sizeof(name), "ioc_dump");
+	ioc->ioc_dump =	debugfs_create_file(name, 0444,
+	    ioc->debugfs_root, ioc, &mpt3sas_debugfs_iocdump_fops);
+	if (!ioc->ioc_dump) {
+		dev_err(&ioc->pdev->dev,
+		    "Cannot create ioc_dump debugfs file\n");
+		debugfs_remove(ioc->debugfs_root);
+		return;
+	}
+
+	snprintf(name, sizeof(name), "host_recovery");
+	debugfs_create_u8(name, 0444, ioc->debugfs_root, &ioc->shost_recovery);
+
+}
+
+/*
+ * mpt3sas_destroy_debugfs :	Destroy debugfs per HBA adapter
+ * @ioc:	MPT3SAS_ADAPTER object
+ */
+void mpt3sas_destroy_debugfs(struct MPT3SAS_ADAPTER *ioc)
+{
+	debugfs_remove_recursive(ioc->debugfs_root);
+}
+