[PATCH 3/3] dmaengine: ae4dma: Add debugfs entries for AE4DMA

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

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

Expose data about the configuration and operation of the
AE4DMA through debugfs entries: device name, capabilities,
configuration, statistics.

Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
---
 drivers/dma/ae4dma/Makefile         |  2 +-
 drivers/dma/ae4dma/ae4dma-debugfs.c | 98 +++++++++++++++++++++++++++++++++++++
 drivers/dma/ae4dma/ae4dma-dev.c     | 16 ++++++
 drivers/dma/ae4dma/ae4dma.h         |  8 +++
 4 files changed, 123 insertions(+), 1 deletion(-)
 create mode 100644 drivers/dma/ae4dma/ae4dma-debugfs.c

diff --git a/drivers/dma/ae4dma/Makefile b/drivers/dma/ae4dma/Makefile
index b1e4318..4082fec 100644
--- a/drivers/dma/ae4dma/Makefile
+++ b/drivers/dma/ae4dma/Makefile
@@ -5,6 +5,6 @@
 
 obj-$(CONFIG_AMD_AE4DMA) += ae4dma.o
 
-ae4dma-objs := ae4dma-dev.o ae4dma-dmaengine.o
+ae4dma-objs := ae4dma-dev.o ae4dma-dmaengine.o ae4dma-debugfs.o
 
 ae4dma-$(CONFIG_PCI) += ae4dma-pci.o
diff --git a/drivers/dma/ae4dma/ae4dma-debugfs.c b/drivers/dma/ae4dma/ae4dma-debugfs.c
new file mode 100644
index 0000000..ae6ec7d
--- /dev/null
+++ b/drivers/dma/ae4dma/ae4dma-debugfs.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD AE4DMA device driver
+ * -- Based on the PTDMA driver
+ *
+ * Copyright (C) 2023 Advanced Micro Devices, Inc.
+ *
+ * Author: Sanjay R Mehta <sanju.mehta@amd.com>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+#include "ae4dma.h"
+
+/* DebugFS helpers */
+#define	RI_VERSION_NUM	0x0000003F
+
+#define	RI_NUM_VQM	0x00078000
+#define	RI_NVQM_SHIFT	15
+
+static int ae4_debugfs_info_show(struct seq_file *s, void *p)
+{
+	struct ae4_device *ae4 = s->private;
+	unsigned int regval;
+
+	seq_printf(s, "Device name: %s\n", dev_name(ae4->dev));
+	seq_printf(s, "   # Queues: %d\n", 1);
+	seq_printf(s, "     # Cmds: %d\n", ae4->cmd_count);
+
+	regval = ioread32(ae4->io_regs + CMD_AE4_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 AE4DMA
+ */
+static int ae4_debugfs_stats_show(struct seq_file *s, void *p)
+{
+	struct ae4_device *ae4 = s->private;
+
+	seq_printf(s, "Total Interrupts Handled: %ld\n", ae4->total_interrupts);
+
+	return 0;
+}
+
+static int ae4_debugfs_queue_show(struct seq_file *s, void *p)
+{
+	struct ae4_cmd_queue *cmd_q = s->private;
+
+	if (!cmd_q)
+		return 0;
+
+	seq_printf(s, "        Total CMDs submitted: %ld\n", cmd_q->total_ae4_ops);
+	seq_printf(s, "        Total CMDs in q%d: %ld\n", cmd_q->id, cmd_q->q_cmd_count);
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(ae4_debugfs_info);
+DEFINE_SHOW_ATTRIBUTE(ae4_debugfs_queue);
+DEFINE_SHOW_ATTRIBUTE(ae4_debugfs_stats);
+
+void ae4dma_debugfs_setup(struct ae4_device *ae4)
+{
+	struct ae4_cmd_queue *cmd_q;
+	struct dentry *debugfs_q_instance;
+	unsigned int i;
+	char name[30];
+
+	if (!debugfs_initialized())
+		return;
+
+	debugfs_create_file("info", 0400, ae4->dma_dev.dbg_dev_root, ae4,
+			    &ae4_debugfs_info_fops);
+
+	debugfs_create_file("stats", 0400, ae4->dma_dev.dbg_dev_root, ae4,
+			    &ae4_debugfs_stats_fops);
+
+	for (i = 0; i < ae4->cmd_q_count; i++) {
+		cmd_q = &ae4->cmd_q[i];
+
+		snprintf(name, 29, "q%d", cmd_q->id);
+
+		debugfs_q_instance =
+			debugfs_create_dir(name, ae4->dma_dev.dbg_dev_root);
+
+		debugfs_create_file("stats", 0400, debugfs_q_instance, cmd_q,
+				    &ae4_debugfs_queue_fops);
+	}
+}
diff --git a/drivers/dma/ae4dma/ae4dma-dev.c b/drivers/dma/ae4dma/ae4dma-dev.c
index af7e510..fe5af0c0 100644
--- a/drivers/dma/ae4dma/ae4dma-dev.c
+++ b/drivers/dma/ae4dma/ae4dma-dev.c
@@ -74,6 +74,7 @@ static int ae4_core_execute_cmd(struct ae4dma_desc *desc, struct ae4_cmd_queue *
 {
 	bool soc = FIELD_GET(DWORD0_SOC, desc->dw0);
 	u8 *q_desc = (u8 *)&cmd_q->qbase[0];
+	unsigned long flags;
 	u32 tail_wi;
 
 	cmd_q->int_rcvd = 0;
@@ -99,6 +100,10 @@ static int ae4_core_execute_cmd(struct ae4dma_desc *desc, struct ae4_cmd_queue *
 	tail_wi = (tail_wi + 1) % CMD_Q_LEN;
 	iowrite32(tail_wi, cmd_q->reg_control + 0x10);
 
+	spin_lock_irqsave(&cmd_q->cmd_lock, flags);
+	cmd_q->q_cmd_count++;
+	spin_unlock_irqrestore(&cmd_q->cmd_lock, flags);
+
 	mutex_unlock(&cmd_q->q_mutex);
 
 	return 0;
@@ -110,6 +115,7 @@ int ae4_core_perform_passthru(struct ae4_cmd_queue *cmd_q, struct ae4_passthru_e
 	struct ae4_device *ae4 = cmd_q->ae4;
 
 	cmd_q->cmd_error = 0;
+	cmd_q->total_ae4_ops++;
 	memset(&desc, 0, sizeof(desc));
 	desc.dw0 = CMD_DESC_DW0_VAL;
 	desc.dw1.status = 0;
@@ -173,9 +179,12 @@ static irqreturn_t ae4_core_irq_handler(int irq, void *data)
 {
 	struct ae4_cmd_queue *cmd_q = data;
 	struct ae4_device *ae4 = cmd_q->ae4;
+	unsigned long flags;
 	u32 status = ioread32(cmd_q->reg_control + 0x4);
 	u8 q_intr_type = (status >> 24) & 0xf;
 
+	ae4->total_interrupts++;
+
 	if (q_intr_type ==  0x4)
 		dev_info(ae4->dev, "AE4DMA INTR: %s (0x%x)\n", "queue desc error", q_intr_type);
 	else if (q_intr_type ==  0x2)
@@ -187,6 +196,10 @@ static irqreturn_t ae4_core_irq_handler(int irq, void *data)
 
 	ae4_check_status_trans(ae4, cmd_q);
 
+	spin_lock_irqsave(&cmd_q->cmd_lock, flags);
+	cmd_q->q_cmd_count--;
+	spin_unlock_irqrestore(&cmd_q->cmd_lock, flags);
+
 	tasklet_schedule(&cmd_q->irq_tasklet);
 
 	return IRQ_HANDLED;
@@ -283,6 +296,9 @@ int ae4_core_init(struct ae4_device *ae4)
 	if (ret)
 		goto e_free_irq;
 
+	/* Set up debugfs entries */
+	ae4dma_debugfs_setup(ae4);
+
 	return 0;
 
 e_free_irq:
diff --git a/drivers/dma/ae4dma/ae4dma.h b/drivers/dma/ae4dma/ae4dma.h
index d341c35..ae31b26 100644
--- a/drivers/dma/ae4dma/ae4dma.h
+++ b/drivers/dma/ae4dma/ae4dma.h
@@ -231,6 +231,10 @@ struct ae4_cmd_queue {
 	wait_queue_head_t q_space;
 	unsigned int q_space_available;
 
+	/* Queue Statistics */
+	unsigned long total_ae4_ops;
+	unsigned long q_cmd_count;
+
 	struct ae4_tasklet_data tdata;
 	struct tasklet_struct irq_tasklet;
 
@@ -274,6 +278,9 @@ struct ae4_device {
 	struct kmem_cache *dma_desc_cache;
 
 	wait_queue_head_t lsb_queue;
+
+	/* Device Statistics */
+	unsigned long total_interrupts;
 };
 
 /*
@@ -326,6 +333,7 @@ struct ae4_dev_vdata {
 int ae4_dmaengine_register(struct ae4_device *ae4);
 void ae4_dmaengine_unregister(struct ae4_device *ae4);
 
+void ae4dma_debugfs_setup(struct ae4_device *ae4);
 int ae4_core_init(struct ae4_device *ae4);
 void ae4_core_destroy(struct ae4_device *ae4);
 
-- 
2.7.4