[PATCH 4/4] dmaengine: Add debugfs entries for PTDMA information

[PATCH 4/4] dmaengine: Add debugfs entries for PTDMA information

[Mehta, Sanju]

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>
Reviewed-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Reviewed-by: Rajesh Kumar <Rajesh1.Kumar@amd.com>
---
 drivers/dma/ptdma/Makefile        |   3 +-
 drivers/dma/ptdma/ptdma-debugfs.c | 249 ++++++++++++++++++++++++++++++++++++++
 drivers/dma/ptdma/ptdma-dev.c     |  15 +++
 drivers/dma/ptdma/ptdma.h         |  14 +++
 4 files changed, 280 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 5fc174a..0c8ee97 100644
--- a/drivers/dma/ptdma/Makefile
+++ b/drivers/dma/ptdma/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_AMD_PTDMA) += ptdma.o
 
 ptdma-objs := ptdma-ops.o \
 	      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..ec5d3d3
--- /dev/null
+++ b/drivers/dma/ptdma/ptdma-debugfs.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD Passthrough DMA device driver
+ *
+ * Copyright (C) 2019 Advanced Micro Devices, Inc.
+ *
+ * Author: Sanjay R Mehta <sanju.mehta@amd.com>
+ *
+ * Based on CCP driver
+ *	Original copyright message:
+ *
+ *  Copyright (C) 2017 Advanced Micro Devices, Inc.
+ *
+ *  Author: Gary R Hook <gary.hook@amd.com>
+ */
+
+#include <linux/debugfs.h>
+
+#include "ptdma.h"
+
+/* DebugFS helpers */
+#define	OBUFP		(obuf + oboff)
+#define	OBUFLEN		512
+#define	OBUFSPC		(OBUFLEN - oboff)
+#define	OSCNPRINTF(fmt, ...) \
+		scnprintf(OBUFP, OBUFSPC, fmt, ## __VA_ARGS__)
+
+#define	MAX_NAME_LEN	20
+#define	BUFLEN	63
+#define	RI_VERSION_NUM	0x0000003F
+
+#define	RI_NUM_VQM	0x00078000
+#define	RI_NVQM_SHIFT	15
+#define	RI_NVQM(r)	(((r) * RI_NUM_VQM) >> RI_NVQM_SHIFT)
+#define	RI_LSB_ENTRIES	0x0FF80000
+#define	RI_NLSB_SHIFT	19
+#define	RI_NLSB(r)	(((r) * RI_LSB_ENTRIES) >> RI_NLSB_SHIFT)
+
+static struct dentry *pt_debugfs_dir;
+static DEFINE_MUTEX(pt_debugfs_lock);
+
+static ssize_t ptdma_debugfs_info_read(struct file *filp, char __user *ubuf,
+				      size_t count, loff_t *offp)
+{
+	struct pt_device *pt = filp->private_data;
+	unsigned int oboff = 0;
+	unsigned int regval;
+	ssize_t ret;
+	char *obuf;
+
+	if (!pt)
+		return 0;
+
+	obuf = kmalloc(OBUFLEN, GFP_KERNEL);
+	if (!obuf)
+		return -ENOMEM;
+
+	oboff += OSCNPRINTF("Device name: %s\n", pt->name);
+	oboff += OSCNPRINTF("   # Queues: %d\n", 1);
+	oboff += OSCNPRINTF("     # Cmds: %d\n", pt->cmd_count);
+
+	regval = ioread32(pt->io_regs + CMD_PT_VERSION);
+
+	oboff += OSCNPRINTF("    Version: %d\n", regval & RI_VERSION_NUM);
+	oboff += OSCNPRINTF("    Engines:");
+	oboff += OSCNPRINTF("\n");
+	oboff += OSCNPRINTF("     Queues: %d\n",
+		   (regval & RI_NUM_VQM) >> RI_NVQM_SHIFT);
+	oboff += OSCNPRINTF("LSB Entries: %d\n",
+		   (regval & RI_LSB_ENTRIES) >> RI_NLSB_SHIFT);
+
+	ret = simple_read_from_buffer(ubuf, count, offp, obuf, oboff);
+	kfree(obuf);
+
+	return ret;
+}
+
+/* Return a formatted buffer containing the current
+ * statistics of queue for PTDMA
+ */
+static ssize_t ptdma_debugfs_stats_read(struct file *filp, char __user *ubuf,
+				       size_t count, loff_t *offp)
+{
+	struct pt_device *pt = filp->private_data;
+	unsigned long total_pt_ops = 0;
+	unsigned long total_ops = 0;
+	unsigned int oboff = 0;
+	ssize_t ret = 0;
+	char *obuf;
+	struct pt_cmd_queue *cmd_q = &pt->cmd_q;
+
+	total_ops += cmd_q->total_ops;
+	total_pt_ops += cmd_q->total_pt_ops;
+
+	obuf = kmalloc(OBUFLEN, GFP_KERNEL);
+	if (!obuf)
+		return -ENOMEM;
+
+	oboff += OSCNPRINTF("Total Interrupts Handled: %ld\n",
+			    pt->total_interrupts);
+	oboff += OSCNPRINTF("        Total Operations: %ld\n",
+			    total_ops);
+	oboff += OSCNPRINTF("               Pass-Thru: %ld\n",
+			    total_pt_ops);
+
+	ret = simple_read_from_buffer(ubuf, count, offp, obuf, oboff);
+	kfree(obuf);
+
+	return ret;
+}
+
+/* Reset the counters in a queue
+ */
+static void ptdma_debugfs_reset_queue_stats(struct pt_cmd_queue *cmd_q)
+{
+	cmd_q->total_ops = 0L;
+	cmd_q->total_pt_ops = 0L;
+}
+
+/* A value was written to the stats variable, which
+ * should be used to reset the queue counters across
+ * that device.
+ */
+static ssize_t ptdma_debugfs_stats_write(struct file *filp,
+					const char __user *ubuf,
+					size_t count, loff_t *offp)
+{
+	struct pt_device *pt = filp->private_data;
+
+	ptdma_debugfs_reset_queue_stats(&pt->cmd_q);
+	pt->total_interrupts = 0L;
+
+	return count;
+}
+
+/* Return a formatted buffer containing the current information
+ * for that queue
+ */
+static ssize_t ptdma_debugfs_queue_read(struct file *filp, char __user *ubuf,
+				       size_t count, loff_t *offp)
+{
+	struct pt_cmd_queue *cmd_q = filp->private_data;
+	unsigned int oboff = 0;
+	unsigned int regval;
+	ssize_t ret;
+	char *obuf;
+
+	if (!cmd_q)
+		return 0;
+
+	obuf = kmalloc(OBUFLEN, GFP_KERNEL);
+	if (!obuf)
+		return -ENOMEM;
+
+	oboff += OSCNPRINTF("  Total Queue Operations: %ld\n",
+			    cmd_q->total_ops);
+	oboff += OSCNPRINTF("               Pass-Thru: %ld\n",
+			    cmd_q->total_pt_ops);
+
+	regval = ioread32(cmd_q->reg_int_enable);
+	oboff += OSCNPRINTF("      Enabled Interrupts:");
+	if (regval & INT_EMPTY_QUEUE)
+		oboff += OSCNPRINTF(" EMPTY");
+	if (regval & INT_QUEUE_STOPPED)
+		oboff += OSCNPRINTF(" STOPPED");
+	if (regval & INT_ERROR)
+		oboff += OSCNPRINTF(" ERROR");
+	if (regval & INT_COMPLETION)
+		oboff += OSCNPRINTF(" COMPLETION");
+	oboff += OSCNPRINTF("\n");
+
+	ret = simple_read_from_buffer(ubuf, count, offp, obuf, oboff);
+	kfree(obuf);
+
+	return ret;
+}
+
+/* A value was written to the stats variable for a
+ * queue. Reset the queue counters to this value.
+ */
+static ssize_t ptdma_debugfs_queue_write(struct file *filp,
+					const char __user *ubuf,
+					size_t count, loff_t *offp)
+{
+	struct pt_cmd_queue *cmd_q = filp->private_data;
+
+	ptdma_debugfs_reset_queue_stats(cmd_q);
+
+	return count;
+}
+
+static const struct file_operations pt_debugfs_info_ops = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read = ptdma_debugfs_info_read,
+	.write = NULL,
+};
+
+static const struct file_operations pt_debugfs_queue_ops = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read = ptdma_debugfs_queue_read,
+	.write = ptdma_debugfs_queue_write,
+};
+
+static const struct file_operations pt_debugfs_stats_ops = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read = ptdma_debugfs_stats_read,
+	.write = ptdma_debugfs_stats_write,
+};
+
+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->debugfs_instance = debugfs_create_dir(pt->name, pt_debugfs_dir);
+
+	debugfs_create_file("info", 0400, pt->debugfs_instance, pt,
+			    &pt_debugfs_info_ops);
+
+	debugfs_create_file("stats", 0600, pt->debugfs_instance, pt,
+			    &pt_debugfs_stats_ops);
+
+	cmd_q = &pt->cmd_q;
+
+	snprintf(name, MAX_NAME_LEN - 1, "q");
+
+	debugfs_q_instance =
+		debugfs_create_dir(name, pt->debugfs_instance);
+
+	debugfs_create_file("stats", 0600, debugfs_q_instance, cmd_q,
+			    &pt_debugfs_queue_ops);
+}
+
+void ptdma_debugfs_destroy(void)
+{
+	debugfs_remove_recursive(pt_debugfs_dir);
+}
diff --git a/drivers/dma/ptdma/ptdma-dev.c b/drivers/dma/ptdma/ptdma-dev.c
index 1a7a982..29a8c40 100644
--- a/drivers/dma/ptdma/ptdma-dev.c
+++ b/drivers/dma/ptdma/ptdma-dev.c
@@ -18,6 +18,7 @@
 #include <linux/kernel.h>
 #include <linux/pci.h>
 #include <linux/kthread.h>
+#include <linux/debugfs.h>
 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
 
@@ -102,6 +103,8 @@ static int pt_core_execute_cmd(struct ptdma_desc *desc,
 	int	i;
 	int ret = 0;
 
+	cmd_q->total_ops++;
+
 	if (PT_CMD_SOC(desc)) {
 		PT_CMD_IOC(desc) = 1;
 		PT_CMD_SOC(desc) = 0;
@@ -153,6 +156,8 @@ int pt_core_perform_passthru(struct pt_op *op)
 	union pt_function function;
 	struct pt_dma_info *saddr = &op->src.u.dma;
 
+	op->cmd_q->total_pt_ops++;
+
 	memset(&desc, 0, Q_DESC_SIZE);
 
 	PT_CMD_ENGINE(&desc) = PT_ENGINE_PASSTHRU;
@@ -222,6 +227,7 @@ static irqreturn_t pt_core_irq_handler(int irq, void *data)
 	struct pt_device *pt = (struct pt_device *)data;
 
 	pt_core_disable_queue_interrupts(pt);
+	pt->total_interrupts++;
 	tasklet_schedule(&pt->irq_tasklet);
 
 	return IRQ_HANDLED;
@@ -362,6 +368,9 @@ int pt_core_init(struct pt_device *pt)
 	if (ret)
 		goto e_kthread;
 
+	/* Set up debugfs entries */
+	ptdma_debugfs_setup(pt);
+
 	return 0;
 
 
@@ -393,6 +402,12 @@ void pt_core_destroy(struct pt_device *pt)
 	/* Remove this device from the list of available units first */
 	pt_del_device(pt);
 
+	/* We're in the process of tearing down the entire driver;
+	 * when all the devices are gone clean up debugfs
+	 */
+	if (pt_present())
+		ptdma_debugfs_destroy();
+
 	/* Disable and clear interrupts */
 	pt_core_disable_queue_interrupts(pt);
 
diff --git a/drivers/dma/ptdma/ptdma.h b/drivers/dma/ptdma/ptdma.h
index e8bb4e7..ba23d50 100644
--- a/drivers/dma/ptdma/ptdma.h
+++ b/drivers/dma/ptdma/ptdma.h
@@ -53,6 +53,7 @@
 #define	CMD_QUEUE_PRIO_OFFSET		0x00
 #define	CMD_REQID_CONFIG_OFFSET		0x04
 #define	CMD_TIMEOUT_OFFSET		0x08
+#define	CMD_PT_VERSION			0x10
 
 #define CMD_Q_CONTROL_BASE		0x0000
 #define CMD_Q_TAIL_LO_BASE		0x0004
@@ -312,6 +313,10 @@ struct pt_cmd_queue {
 	/* Interrupt wait queue */
 	wait_queue_head_t int_queue;
 	unsigned int int_rcvd;
+
+	/* Per-queue Statistics */
+	unsigned long total_ops;
+	unsigned long total_pt_ops;
 } ____cacheline_aligned;
 
 struct pt_device {
@@ -357,6 +362,12 @@ struct pt_device {
 	/* Suspend support */
 	unsigned int suspending;
 	wait_queue_head_t suspend_queue;
+
+	/* Device Statistics */
+	unsigned long total_interrupts;
+
+	/* DebugFS info */
+	struct dentry *debugfs_instance;
 };
 
 struct pt_dma_info {
@@ -503,6 +514,9 @@ int pt_run_cmd(struct pt_cmd_queue *cmd_q, struct pt_cmd *cmd);
 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(void);
+
 int pt_core_init(struct pt_device *pt);
 void pt_core_destroy(struct pt_device *pt);
 
-- 
2.7.4

Re: [PATCH 4/4] dmaengine: Add debugfs entries for PTDMA information

[gregkh]

On Tue, Sep 24, 2019 at 07:33:02AM +0000, Mehta, Sanju wrote:
> +static const struct file_operations pt_debugfs_info_ops = {
> +	.owner = THIS_MODULE,
> +	.open = simple_open,
> +	.read = ptdma_debugfs_info_read,
> +	.write = NULL,
> +};
> +
> +static const struct file_operations pt_debugfs_queue_ops = {
> +	.owner = THIS_MODULE,
> +	.open = simple_open,
> +	.read = ptdma_debugfs_queue_read,
> +	.write = ptdma_debugfs_queue_write,
> +};
> +
> +static const struct file_operations pt_debugfs_stats_ops = {
> +	.owner = THIS_MODULE,
> +	.open = simple_open,
> +	.read = ptdma_debugfs_stats_read,
> +	.write = ptdma_debugfs_stats_write,
> +};

Can you use DEFINE_SIMPLE_ATTRIBUTE() here intead of these?

thanks,

greg k-h

Re: [PATCH 4/4] dmaengine: Add debugfs entries for PTDMA information

[Sanjay R Mehta]

On 9/24/2019 1:35 PM, gregkh@linuxfoundation.org wrote:
> [CAUTION: External Email]
>
> On Tue, Sep 24, 2019 at 07:33:02AM +0000, Mehta, Sanju wrote:
>> +static const struct file_operations pt_debugfs_info_ops = {
>> +     .owner = THIS_MODULE,
>> +     .open = simple_open,
>> +     .read = ptdma_debugfs_info_read,
>> +     .write = NULL,
>> +};
>> +
>> +static const struct file_operations pt_debugfs_queue_ops = {
>> +     .owner = THIS_MODULE,
>> +     .open = simple_open,
>> +     .read = ptdma_debugfs_queue_read,
>> +     .write = ptdma_debugfs_queue_write,
>> +};
>> +
>> +static const struct file_operations pt_debugfs_stats_ops = {
>> +     .owner = THIS_MODULE,
>> +     .open = simple_open,
>> +     .read = ptdma_debugfs_stats_read,
>> +     .write = ptdma_debugfs_stats_write,
>> +};
> Can you use DEFINE_SIMPLE_ATTRIBUTE() here intead of these?
Okay Greg, noted. This will be resolved in next set of patches.
>
> thanks,
>
> greg k-h

Re: [PATCH 4/4] dmaengine: Add debugfs entries for PTDMA information

[Sanjay R Mehta]

On 9/24/2019 1:35 PM, gregkh@linuxfoundation.org wrote:
> [CAUTION: External Email]
>
> On Tue, Sep 24, 2019 at 07:33:02AM +0000, Mehta, Sanju wrote:
>> +static const struct file_operations pt_debugfs_info_ops = {
>> +     .owner = THIS_MODULE,
>> +     .open = simple_open,
>> +     .read = ptdma_debugfs_info_read,
>> +     .write = NULL,
>> +};
>> +
>> +static const struct file_operations pt_debugfs_queue_ops = {
>> +     .owner = THIS_MODULE,
>> +     .open = simple_open,
>> +     .read = ptdma_debugfs_queue_read,
>> +     .write = ptdma_debugfs_queue_write,
>> +};
>> +
>> +static const struct file_operations pt_debugfs_stats_ops = {
>> +     .owner = THIS_MODULE,
>> +     .open = simple_open,
>> +     .read = ptdma_debugfs_stats_read,
>> +     .write = ptdma_debugfs_stats_write,
>> +};
> Can you use DEFINE_SIMPLE_ATTRIBUTE() here intead of these?


Okay Greg, noted. This will be resolved in next set of patches.

>
> thanks,
>
> greg k-h