linux-kernel - Re: [PATCH v5 3/3] dmaengine: ptdma: Add debugfs entries for PTDMA information

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Date:   Fri, 3 Jul 2020 13:12:00 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     Sanjay R Mehta <Sanju.Mehta@....com>
Cc:     gregkh@...uxfoundation.org, dan.j.williams@...el.com,
        Thomas.Lendacky@....com, Shyam-sundar.S-k@....com,
        Nehal-bakulchandra.Shah@....com, robh@...nel.org,
        mchehab+samsung@...nel.org, davem@...emloft.net,
        linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org
Subject: Re: [PATCH v5 3/3] dmaengine: ptdma: Add debugfs entries for PTDMA
 information

On 16-06-20, 20:11, Sanjay R Mehta wrote:
> From: Sanjay R Mehta <sanju.mehta@....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@....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@....com>
> + * Author: Gary R Hook <gary.hook@....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);

please do not create your own, you already have one under
/sys/kernel/debug/dmaengine/<>/ use that :)

> +	mutex_unlock(&pt_debugfs_lock);
> +
> +	pt->dma_dev.dbg_dev_root = debugfs_create_dir(pt->name, pt_debugfs_dir);

argh, this is already created by core and you leaked that one and added
your own!

-- 
~Vinod