[PATCH v5 3/3] dmaengine: ptdma: Add debugfs entries for PTDMA information

[Sanjay R Mehta <Sanju.Mehta@amd.com>]

From: Sanjay R Mehta <sanju.mehta@amd.com>

Expose data about the configuration and operation of the
PTDMA through debugfs entries: device name, capabilities,
configuration, statistics.

Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
---
 drivers/dma/ptdma/Makefile        |   3 +-
 drivers/dma/ptdma/ptdma-debugfs.c | 130 ++++++++++++++++++++++++++++++++++++++
 drivers/dma/ptdma/ptdma-dev.c     |   8 +++
 drivers/dma/ptdma/ptdma.h         |   9 +++
 4 files changed, 149 insertions(+), 1 deletion(-)
 create mode 100644 drivers/dma/ptdma/ptdma-debugfs.c

diff --git a/drivers/dma/ptdma/Makefile b/drivers/dma/ptdma/Makefile
index 6fcb4ad..60e7c10 100644
--- a/drivers/dma/ptdma/Makefile
+++ b/drivers/dma/ptdma/Makefile
@@ -6,6 +6,7 @@
 obj-$(CONFIG_AMD_PTDMA) += ptdma.o
 
 ptdma-objs := ptdma-dev.o \
-	      ptdma-dmaengine.o
+	      ptdma-dmaengine.o \
+	      ptdma-debugfs.o
 
 ptdma-$(CONFIG_PCI) += ptdma-pci.o
diff --git a/drivers/dma/ptdma/ptdma-debugfs.c b/drivers/dma/ptdma/ptdma-debugfs.c
new file mode 100644
index 0000000..506c148b
--- /dev/null
+++ b/drivers/dma/ptdma/ptdma-debugfs.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD Passthrough DMA device driver
+ * -- Based on the CCP driver
+ *
+ * Copyright (C) 2016,2020 Advanced Micro Devices, Inc.
+ *
+ * Author: Sanjay R Mehta <sanju.mehta@amd.com>
+ * Author: Gary R Hook <gary.hook@amd.com>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+#include "ptdma.h"
+
+/* DebugFS helpers */
+#define	MAX_NAME_LEN	20
+#define	RI_VERSION_NUM	0x0000003F
+
+#define	RI_NUM_VQM	0x00078000
+#define	RI_NVQM_SHIFT	15
+
+static struct dentry *pt_debugfs_dir;
+static DEFINE_MUTEX(pt_debugfs_lock);
+
+static int pt_debugfs_info_show(struct seq_file *s, void *p)
+{
+	struct pt_device *pt = s->private;
+	unsigned int regval;
+
+	if (!pt)
+		return 0;
+
+	seq_printf(s, "Device name: %s\n", pt->name);
+	seq_printf(s, "   # Queues: %d\n", 1);
+	seq_printf(s, "     # Cmds: %d\n", pt->cmd_count);
+
+	regval = ioread32(pt->io_regs + CMD_PT_VERSION);
+
+	seq_printf(s, "    Version: %d\n", regval & RI_VERSION_NUM);
+	seq_puts(s, "    Engines:");
+	seq_puts(s, "\n");
+	seq_printf(s, "     Queues: %d\n", (regval & RI_NUM_VQM) >> RI_NVQM_SHIFT);
+
+	return 0;
+}
+
+/*
+ * Return a formatted buffer containing the current
+ * statistics of queue for PTDMA
+ */
+static int pt_debugfs_stats_show(struct seq_file *s, void *p)
+{
+	struct pt_device *pt = s->private;
+
+	seq_printf(s, "Total Interrupts Handled: %ld\n", pt->total_interrupts);
+
+	return 0;
+}
+
+static int pt_debugfs_queue_show(struct seq_file *s, void *p)
+
+{
+	struct pt_cmd_queue *cmd_q = s->private;
+	unsigned int regval;
+
+	if (!cmd_q)
+		return 0;
+
+	seq_printf(s, "               Pass-Thru: %ld\n", cmd_q->total_pt_ops);
+
+	regval = ioread32(cmd_q->reg_int_enable);
+
+	seq_puts(s, "      Enabled Interrupts:");
+	if (regval & INT_EMPTY_QUEUE)
+		seq_puts(s, " EMPTY");
+	if (regval & INT_QUEUE_STOPPED)
+		seq_puts(s, " STOPPED");
+	if (regval & INT_ERROR)
+		seq_puts(s, " ERROR");
+	if (regval & INT_COMPLETION)
+		seq_puts(s, " COMPLETION");
+	seq_puts(s, "\n");
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(pt_debugfs_info);
+DEFINE_SHOW_ATTRIBUTE(pt_debugfs_queue);
+DEFINE_SHOW_ATTRIBUTE(pt_debugfs_stats);
+
+void ptdma_debugfs_setup(struct pt_device *pt)
+{
+	struct pt_cmd_queue *cmd_q;
+	char name[MAX_NAME_LEN + 1];
+	struct dentry *debugfs_q_instance;
+
+	if (!debugfs_initialized())
+		return;
+
+	mutex_lock(&pt_debugfs_lock);
+	if (!pt_debugfs_dir)
+		pt_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
+	mutex_unlock(&pt_debugfs_lock);
+
+	pt->dma_dev.dbg_dev_root = debugfs_create_dir(pt->name, pt_debugfs_dir);
+
+	debugfs_create_file("info", 0400, pt->dma_dev.dbg_dev_root, pt,
+			    &pt_debugfs_info_fops);
+
+	debugfs_create_file("stats", 0600, pt->dma_dev.dbg_dev_root, pt,
+			    &pt_debugfs_stats_fops);
+
+	cmd_q = &pt->cmd_q;
+
+	snprintf(name, MAX_NAME_LEN - 1, "q");
+
+	debugfs_q_instance =
+		debugfs_create_dir(name, pt->dma_dev.dbg_dev_root);
+
+	debugfs_create_file("stats", 0600, debugfs_q_instance, cmd_q,
+			    &pt_debugfs_queue_fops);
+}
+
+void ptdma_debugfs_destroy(struct dma_device *dma_dev)
+{
+	debugfs_remove_recursive(dma_dev->dbg_dev_root);
+	dma_dev->dbg_dev_root = NULL;
+}
diff --git a/drivers/dma/ptdma/ptdma-dev.c b/drivers/dma/ptdma/ptdma-dev.c
index ef10be5..8b13208 100644
--- a/drivers/dma/ptdma/ptdma-dev.c
+++ b/drivers/dma/ptdma/ptdma-dev.c
@@ -14,6 +14,7 @@
 #include <linux/pci.h>
 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
+#include <linux/debugfs.h>
 
 #include "ptdma.h"
 
@@ -107,6 +108,7 @@ int pt_core_perform_passthru(struct pt_cmd_queue *cmd_q,
 
 	cmd_q->cmd_error = 0;
 
+	cmd_q->total_pt_ops++;
 	memset(&desc, 0, Q_DESC_SIZE);
 
 	desc.dw0.val = CMD_DESC_DW0_VAL;
@@ -159,6 +161,7 @@ static irqreturn_t pt_core_irq_handler(int irq, void *data)
 	u32 status;
 
 	pt_core_disable_queue_interrupts(pt);
+	pt->total_interrupts++;
 
 	status = ioread32(cmd_q->reg_interrupt_status);
 	if (status) {
@@ -290,6 +293,9 @@ int pt_core_init(struct pt_device *pt)
 	if (ret)
 		goto e_dmaengine;
 
+	/* Set up debugfs entries */
+	ptdma_debugfs_setup(pt);
+
 	return 0;
 
 e_dmaengine:
@@ -310,6 +316,8 @@ void pt_core_destroy(struct pt_device *pt)
 	struct pt_cmd_queue *cmd_q = &pt->cmd_q;
 	struct pt_cmd *cmd;
 
+	ptdma_debugfs_destroy(&pt->dma_dev);
+
 	/* Unregister the DMA engine */
 	pt_dmaengine_unregister(pt);
 
diff --git a/drivers/dma/ptdma/ptdma.h b/drivers/dma/ptdma/ptdma.h
index 661be6b..db39a4a 100644
--- a/drivers/dma/ptdma/ptdma.h
+++ b/drivers/dma/ptdma/ptdma.h
@@ -239,6 +239,9 @@ struct pt_cmd_queue {
 	u32 q_status;
 	u32 q_int_status;
 	u32 cmd_error;
+
+	/* queue Statistics */
+	unsigned long total_pt_ops;
 } ____cacheline_aligned;
 
 struct pt_device {
@@ -277,6 +280,9 @@ struct pt_device {
 
 	wait_queue_head_t lsb_queue;
 
+	/* Device Statistics */
+	unsigned long total_interrupts;
+
 	struct pt_tasklet_data tdata;
 };
 
@@ -343,6 +349,9 @@ struct pt_dev_vdata {
 int pt_dmaengine_register(struct pt_device *pt);
 void pt_dmaengine_unregister(struct pt_device *pt);
 
+void ptdma_debugfs_setup(struct pt_device *pt);
+void ptdma_debugfs_destroy(struct dma_device *dma_dev);
+
 int pt_core_init(struct pt_device *pt);
 void pt_core_destroy(struct pt_device *pt);
 
-- 
2.7.4