Re: [PATCH v4 3/3] dmaengine: ptdma: Add debugfs entries for PTDMA information

Vinod Koul
2020-05-04T06:20:08Z

On 28-04-20, 16:13, Sanjay R Mehta wrote:
> 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 | 3 +-
> drivers/dma/ptdma/ptdma-debugfs.c | 237 ++++++++++++++++++++++++++++++++++++++
> drivers/dma/ptdma/ptdma-dev.c | 26 +++++
> drivers/dma/ptdma/ptdma.h | 13 +++
> 4 files changed, 278 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..837c43c
> --- /dev/null
> +++ b/drivers/dma/ptdma/ptdma-debugfs.c
> @@ -0,0 +1,237 @@
> +// 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@amd.com>
> + * 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 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 += snprintf(OBUFP, OBUFSPC, "Device name: %s\n", pt->name);
> + oboff += snprintf(OBUFP, OBUFSPC, " # Queues: %d\n", 1);
> + oboff += snprintf(OBUFP, OBUFSPC, " # Cmds: %d\n", pt->cmd_count);
> +
> + regval = ioread32(pt->io_regs + CMD_PT_VERSION);
> +
> + oboff += snprintf(OBUFP, OBUFSPC, " Version: %d\n",
> + regval & RI_VERSION_NUM);
> + oboff += snprintf(OBUFP, OBUFSPC, " Engines:");
> + oboff += snprintf(OBUFP, OBUFSPC, "\n");
> + oboff += snprintf(OBUFP, OBUFSPC, " Queues: %d\n",
> + (regval & RI_NUM_VQM) >> RI_NVQM_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 int oboff = 0;
> + ssize_t ret = 0;
> + char *obuf;
> + struct pt_cmd_queue *cmd_q = &pt->cmd_q;
> +
> + total_pt_ops += cmd_q->total_pt_ops;
> +
> + obuf = kmalloc(OBUFLEN, GFP_KERNEL);
> + if (!obuf)
> + return -ENOMEM;
> +
> + oboff += snprintf(OBUFP, OBUFSPC, "Total Interrupts Handled: %ld\n",
> + pt->total_interrupts);
> +
> + 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_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 += snprintf(OBUFP, OBUFSPC, " Pass-Thru: %ld\n",
> + cmd_q->total_pt_ops);
> +
> + regval = ioread32(cmd_q->reg_int_enable);
> + oboff += snprintf(OBUFP, OBUFSPC, " Enabled Interrupts:");
> + if (regval & INT_EMPTY_QUEUE)
> + oboff += snprintf(OBUFP, OBUFSPC, " EMPTY");
> + if (regval & INT_QUEUE_STOPPED)
> + oboff += snprintf(OBUFP, OBUFSPC, " STOPPED");
> + if (regval & INT_ERROR)
> + oboff += snprintf(OBUFP, OBUFSPC, " ERROR");
> + if (regval & INT_COMPLETION)
> + oboff += snprintf(OBUFP, OBUFSPC, " COMPLETION");
> + oboff += snprintf(OBUFP, OBUFSPC, "\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,
> +};

pls convert to use DEFINE_SHOW_ATTRIBUTE()

> +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);

Pls use dbg_dev_root in struct dma_device as root for your own debugfs

Thanks
--
~Vinod