[PATCH v9 3/3] dmaengine: ptdma: Add debugfs entries for PTDMA

Sanjay R Mehta
2021-06-02T17:23:10Z

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 | 2 +-
drivers/dma/ptdma/ptdma-debugfs.c | 115 ++++++++++++++++++++++++++++++++++++++
drivers/dma/ptdma/ptdma-dev.c | 5 ++
drivers/dma/ptdma/ptdma.h | 6 ++
4 files changed, 127 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 a528cb0..ce54102 100644
--- a/drivers/dma/ptdma/Makefile
+++ b/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
diff --git a/drivers/dma/ptdma/ptdma-debugfs.c b/drivers/dma/ptdma/ptdma-debugfs.c
new file mode 100644
index 0000000..1f69159
--- /dev/null
+++ b/drivers/dma/ptdma/ptdma-debugfs.c
@@ -0,0 +1,115 @@
+// 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 <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 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;
+
+ 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);
+}
diff --git a/drivers/dma/ptdma/ptdma-dev.c b/drivers/dma/ptdma/ptdma-dev.c
index 7122933..ba37b81 100644
--- a/drivers/dma/ptdma/ptdma-dev.c
+++ b/drivers/dma/ptdma/ptdma-dev.c
@@ -103,6 +103,7 @@ 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;
@@ -151,6 +152,7 @@ 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) {
@@ -272,6 +274,9 @@ 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:
diff --git a/drivers/dma/ptdma/ptdma.h b/drivers/dma/ptdma/ptdma.h
index bc6676d..a02f47a 100644
--- a/drivers/dma/ptdma/ptdma.h
+++ b/drivers/dma/ptdma/ptdma.h
@@ -233,6 +233,8 @@ 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 {
@@ -271,6 +273,9 @@ struct pt_device {

wait_queue_head_t lsb_queue;

+ /* Device Statistics */
+ unsigned long total_interrupts;
+
struct pt_tasklet_data tdata;
};

@@ -324,6 +329,7 @@ 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);

--
2.7.4