dmaengine: ptdma: Add debugfs entries for PTDMA

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

Signed-off-by: Sanjay R Mehta <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vinod Koul <[email protected]>

Author: Sanjay R Mehta

drivers/dma/ptdma/Makefile

@@ -5,6 +5,6 @@
 
 obj-$(CONFIG_AMD_PTDMA) += ptdma.o
 
-ptdma-objs := ptdma-dev.o ptdma-dmaengine.o
+ptdma-objs := ptdma-dev.o ptdma-dmaengine.o ptdma-debugfs.o
 
 ptdma-$(CONFIG_PCI) += ptdma-pci.o

drivers/dma/ptdma/ptdma-debugfs.c

@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD Passthrough DMA device driver
+ * -- Based on the CCP driver
+ *
+ * Copyright (C) 2016,2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Sanjay R Mehta <[email protected]>
+ * Author: Gary R Hook <[email protected]>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+#include "ptdma.h"
+
+/* DebugFS helpers */
+#define	RI_VERSION_NUM	0x0000003F
+
+#define	RI_NUM_VQM	0x00078000
+#define	RI_NVQM_SHIFT	15
+
+static int pt_debugfs_info_show(struct seq_file *s, void *p)
+{
+	struct pt_device *pt = s->private;
+	unsigned int regval;
+
+	seq_printf(s, "Device name: %s\n", dev_name(pt->dev));
+	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_control + 0x000C);
+
+	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;
+	struct dentry *debugfs_q_instance;
+
+	if (!debugfs_initialized())
+		return;
+
+	debugfs_create_file("info", 0400, pt->dma_dev.dbg_dev_root, pt,
+			    &pt_debugfs_info_fops);
+
+	debugfs_create_file("stats", 0400, pt->dma_dev.dbg_dev_root, pt,
+			    &pt_debugfs_stats_fops);
+
+	cmd_q = &pt->cmd_q;
+
+	debugfs_q_instance =
+		debugfs_create_dir("q", pt->dma_dev.dbg_dev_root);
+
+	debugfs_create_file("stats", 0400, debugfs_q_instance, cmd_q,
+			    &pt_debugfs_queue_fops);
+}

drivers/dma/ptdma/ptdma-dev.c

@@ -102,6 +102,7 @@ int pt_core_perform_passthru(struct pt_cmd_queue *cmd_q,
 	struct ptdma_desc desc;
 
 	cmd_q->cmd_error = 0;
+	cmd_q->total_pt_ops++;
 	memset(&desc, 0, sizeof(desc));
 	desc.dw0 = CMD_DESC_DW0_VAL;
 	desc.length = pt_engine->src_len;
@@ -150,6 +151,7 @@ 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_control + 0x0010);
 	if (status) {
 		cmd_q->int_status = status;
@@ -250,6 +252,9 @@ 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:

drivers/dma/ptdma/ptdma.h

@@ -216,6 +216,8 @@ 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 {
@@ -254,6 +256,9 @@ struct pt_device {
 
 	wait_queue_head_t lsb_queue;
 
+	/* Device Statistics */
+	unsigned long total_interrupts;
+
 	struct pt_tasklet_data tdata;
 };
 
@@ -307,6 +312,7 @@ 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);
 int pt_core_init(struct pt_device *pt);
 void pt_core_destroy(struct pt_device *pt);