Date:   Sat, 4 Jul 2020 21:11:40 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To:     Bhaumik Bhatt <bbhatt@...eaurora.org>
Cc:     linux-arm-msm@...r.kernel.org, hemantk@...eaurora.org,
        jhugo@...eaurora.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 7/9] bus: mhi: core: Introduce debugfs entries and
 counters for MHI

On Mon, Jun 29, 2020 at 09:39:40AM -0700, Bhaumik Bhatt wrote:
> Introduce debugfs entries to show state, register, channel, and event
> ring information. Add MHI state counters to keep track of the state
> changes on the device. Also, allow the host to trigger a device reset,
> issue votes, and change the MHI timeout to help in debug.
> 
> Signed-off-by: Bhaumik Bhatt <bbhatt@...eaurora.org>
> ---
>  drivers/bus/mhi/Kconfig         |   8 +
>  drivers/bus/mhi/core/Makefile   |   5 +-
>  drivers/bus/mhi/core/debugfs.c  | 444 ++++++++++++++++++++++++++++++++++++++++
>  drivers/bus/mhi/core/init.c     |   7 +
>  drivers/bus/mhi/core/internal.h |  24 +++
>  drivers/bus/mhi/core/pm.c       |   4 +
>  include/linux/mhi.h             |   4 +
>  7 files changed, 493 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/bus/mhi/core/debugfs.c
> 
> diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
> index a8bd9bd..6a217ff 100644
> --- a/drivers/bus/mhi/Kconfig
> +++ b/drivers/bus/mhi/Kconfig
> @@ -12,3 +12,11 @@ config MHI_BUS
>  	 communication protocol used by the host processors to control
>  	 and communicate with modem devices over a high speed peripheral
>  	 bus or shared memory.
> +
> +config MHI_BUS_DEBUG
> +	bool "Debugfs support for the MHI bus"
> +	depends on MHI_BUS && DEBUG_FS
> +	help
> +	 Enable debugfs support for use with the MHI transport. Allows
> +	 reading and/or modifying some values within the MHI controller
> +	 for debug and test purposes.
> diff --git a/drivers/bus/mhi/core/Makefile b/drivers/bus/mhi/core/Makefile
> index 66e2700..460a548 100644
> --- a/drivers/bus/mhi/core/Makefile
> +++ b/drivers/bus/mhi/core/Makefile
> @@ -1,3 +1,2 @@
> -obj-$(CONFIG_MHI_BUS) := mhi.o
> -
> -mhi-y := init.o main.o pm.o boot.o
> +obj-$(CONFIG_MHI_BUS) := init.o main.o pm.o boot.o
> +obj-$(CONFIG_MHI_BUS_DEBUG) += debugfs.o
> diff --git a/drivers/bus/mhi/core/debugfs.c b/drivers/bus/mhi/core/debugfs.c
> new file mode 100644
> index 0000000..266cbf0
> --- /dev/null
> +++ b/drivers/bus/mhi/core/debugfs.c
> @@ -0,0 +1,444 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2020, The Linux Foundation. All rights reserved.
> + *
> + */
> +
> +#include <linux/debugfs.h>
> +#include <linux/device.h>
> +#include <linux/interrupt.h>
> +#include <linux/list.h>
> +#include <linux/mhi.h>
> +#include "internal.h"
> +
> +static int mhi_debugfs_states_show(struct seq_file *m, void *d)
> +{
> +	struct mhi_controller *mhi_cntrl = m->private;
> +
> +	/* states */
> +	seq_printf(m, "PM state:%s Device:%s MHI state:%s EE:%s wake:%s\n",
> +		   to_mhi_pm_state_str(mhi_cntrl->pm_state),
> +		   mhi_is_active(mhi_cntrl) ? "Active" : "Inactive",
> +		   TO_MHI_STATE_STR(mhi_cntrl->dev_state),
> +		   TO_MHI_EXEC_STR(mhi_cntrl->ee),
> +		   mhi_cntrl->wake_set ? "true" : "false");

Nit: Always use a space after ":".

> +
> +	/* counters */
> +	seq_printf(m, "M0:%u M2:%u M3:%u M3_Fast:%u", mhi_cntrl->M0,
> +		   mhi_cntrl->M2, mhi_cntrl->M3, mhi_cntrl->M3_fast);
> +
> +	seq_printf(m, " device wake:%u pending packets:%u\n",
> +		   atomic_read(&mhi_cntrl->dev_wake),
> +		   atomic_read(&mhi_cntrl->pending_pkts));
> +
> +	return 0;
> +}
> +
> +static int mhi_debugfs_events_show(struct seq_file *m, void *d)
> +{
> +	struct mhi_controller *mhi_cntrl = m->private;
> +	struct mhi_event *mhi_event;
> +	struct mhi_event_ctxt *er_ctxt;
> +	int i;
> +
> +	if (!mhi_is_active(mhi_cntrl)) {
> +		seq_puts(m, "Device not ready\n");
> +		return -ENODEV;
> +	}
> +
> +	er_ctxt = mhi_cntrl->mhi_ctxt->er_ctxt;
> +	mhi_event = mhi_cntrl->mhi_event;
> +	for (i = 0; i < mhi_cntrl->total_ev_rings;
> +						i++, er_ctxt++, mhi_event++) {
> +		struct mhi_ring *ring = &mhi_event->ring;
> +
> +		if (mhi_event->offload_ev) {
> +			seq_printf(m, "Index:%d is an offload event ring\n", i);
> +			continue;
> +		}
> +
> +		seq_printf(m, "Index:%d intmod count:%lu time:%lu",
> +			   i, (er_ctxt->intmod & EV_CTX_INTMODC_MASK) >>
> +			   EV_CTX_INTMODC_SHIFT,
> +			   (er_ctxt->intmod & EV_CTX_INTMODT_MASK) >>
> +			   EV_CTX_INTMODT_SHIFT);
> +
> +		seq_printf(m, " base:0x%0llx len:0x%llx", er_ctxt->rbase,
> +			   er_ctxt->rlen);
> +
> +		seq_printf(m,
> +			   " rp:0x%llx wp:0x%llx local rp:0x%llx db:0x%llx\n",
> +			   er_ctxt->rp, er_ctxt->wp, (u64)ring->rp,
> +			   mhi_event->db_cfg.db_val);
> +	}
> +
> +	return 0;
> +}
> +
> +static int mhi_debugfs_channels_show(struct seq_file *m, void *d)
> +{
> +	struct mhi_controller *mhi_cntrl = m->private;
> +	struct mhi_chan *mhi_chan;
> +	struct mhi_chan_ctxt *chan_ctxt;
> +	int i;
> +
> +	if (!mhi_is_active(mhi_cntrl)) {
> +		seq_puts(m, "Device not ready\n");
> +		return -ENODEV;
> +	}
> +
> +	mhi_chan = mhi_cntrl->mhi_chan;
> +	chan_ctxt = mhi_cntrl->mhi_ctxt->chan_ctxt;
> +	for (i = 0; i < mhi_cntrl->max_chan; i++, chan_ctxt++, mhi_chan++) {
> +		struct mhi_ring *ring = &mhi_chan->tre_ring;
> +
> +		if (mhi_chan->offload_ch) {
> +			seq_printf(m, "%s(%u) is an offload channel\n",
> +				   mhi_chan->name, mhi_chan->chan);
> +			continue;
> +		}
> +
> +		if (!mhi_chan->mhi_dev)
> +			continue;
> +
> +		seq_printf(m,
> +			   "%s(%u) state:0x%lx brstmode:0x%lx pollcfg:0x%lx",
> +			   mhi_chan->name, mhi_chan->chan, (chan_ctxt->chcfg &
> +			   CHAN_CTX_CHSTATE_MASK) >> CHAN_CTX_CHSTATE_SHIFT,
> +			   (chan_ctxt->chcfg & CHAN_CTX_BRSTMODE_MASK) >>
> +			   CHAN_CTX_BRSTMODE_SHIFT, (chan_ctxt->chcfg &
> +			   CHAN_CTX_POLLCFG_MASK) >> CHAN_CTX_POLLCFG_SHIFT);
> +
> +		seq_printf(m, " type:0x%x event ring:%u", chan_ctxt->chtype,
> +			   chan_ctxt->erindex);
> +
> +		seq_printf(m, " base:0x%llx len:0x%llx wp:0x%llx",
> +			   chan_ctxt->rbase, chan_ctxt->rlen, chan_ctxt->wp);
> +
> +		seq_printf(m, " local rp:0x%llx local wp:0x%llx db:0x%llx\n",
> +			   (u64)ring->rp, (u64)ring->wp,
> +			   mhi_chan->db_cfg.db_val);
> +	}
> +
> +	return 0;
> +}
> +
> +static int mhi_device_votes_show(struct device *dev, void *data)
> +{
> +	struct mhi_device *mhi_dev;
> +
> +	if (dev->bus != &mhi_bus_type)
> +		return 0;
> +
> +	mhi_dev = to_mhi_device(dev);
> +
> +	seq_printf((struct seq_file *)data, "%s: %u\n",
> +		   mhi_dev->name, mhi_dev->dev_wake);
> +
> +	return 0;
> +}
> +
> +static int mhi_debugfs_votes_show(struct seq_file *m, void *d)
> +{
> +	struct mhi_controller *mhi_cntrl = m->private;
> +
> +	if (!mhi_is_active(mhi_cntrl)) {
> +		seq_puts(m, "Device not ready\n");
> +		return -ENODEV;
> +	}
> +
> +	device_for_each_child(mhi_cntrl->cntrl_dev, m, mhi_device_votes_show);
> +
> +	return 0;
> +}
> +
> +static int mhi_debugfs_regdump_show(struct seq_file *m, void *d)
> +{
> +	struct mhi_controller *mhi_cntrl = m->private;
> +	enum mhi_state state;
> +	enum mhi_ee_type ee;
> +	int i, ret = -EIO;
> +	u32 val;
> +	void __iomem *mhi_base = mhi_cntrl->regs;
> +	void __iomem *bhi_base = mhi_cntrl->bhi;
> +	void __iomem *bhie_base = mhi_cntrl->bhie;
> +	void __iomem *wake_db = mhi_cntrl->wake_db;
> +	struct {
> +		const char *name;
> +		int offset;
> +		void __iomem *base;
> +	} debug_regs[] = {
> +		{ "MHI_CTRL", MHICTRL, mhi_base},
> +		{ "MHI_STATUS", MHISTATUS, mhi_base},
> +		{ "MHI_WAKE_DB", 0, wake_db},
> +		{ "BHI_EXECENV", BHI_EXECENV, bhi_base},
> +		{ "BHI_STATUS", BHI_STATUS, bhi_base},
> +		{ "BHI_ERRCODE", BHI_ERRCODE, bhi_base},
> +		{ "BHI_ERRDBG1", BHI_ERRDBG1, bhi_base},
> +		{ "BHI_ERRDBG2", BHI_ERRDBG2, bhi_base},
> +		{ "BHI_ERRDBG3", BHI_ERRDBG3, bhi_base},
> +		{ "BHIE_TXVEC_DB", BHIE_TXVECDB_OFFS, bhie_base},
> +		{ "BHIE_TXVEC_STATUS", BHIE_TXVECSTATUS_OFFS, bhie_base},
> +		{ "BHIE_RXVEC_DB", BHIE_RXVECDB_OFFS, bhie_base},
> +		{ "BHIE_RXVEC_STATUS", BHIE_RXVECSTATUS_OFFS, bhie_base},
> +		{ NULL },
> +	};
> +
> +	if (!MHI_REG_ACCESS_VALID(mhi_cntrl->pm_state))
> +		return ret;
> +
> +	seq_printf(m, "Host PM state:%s Device state:%s EE:%s\n",
> +		   to_mhi_pm_state_str(mhi_cntrl->pm_state),
> +		   TO_MHI_STATE_STR(mhi_cntrl->dev_state),
> +		   TO_MHI_EXEC_STR(mhi_cntrl->ee));
> +
> +	state = mhi_get_mhi_state(mhi_cntrl);
> +	ee = mhi_get_exec_env(mhi_cntrl);
> +	seq_printf(m, "Device EE:%s state:%s\n", TO_MHI_EXEC_STR(ee),
> +		   TO_MHI_STATE_STR(state));
> +
> +	for (i = 0; debug_regs[i].name; i++) {
> +		if (!debug_regs[i].base)
> +			continue;
> +		ret = mhi_read_reg(mhi_cntrl, debug_regs[i].base,
> +				   debug_regs[i].offset, &val);
> +		if (ret)
> +			continue;
> +
> +		seq_printf(m, "%s:0x%x\n", debug_regs[i].name, val);
> +	}
> +
> +	return 0;
> +}
> +
> +static int mhi_debugfs_device_vote_show(struct seq_file *m, void *d)
> +{

The term 'vote' is confusing here. Can you come up with something which portrays
device power mode here?

> +	struct mhi_controller *mhi_cntrl = m->private;
> +	struct mhi_device *mhi_dev = mhi_cntrl->mhi_dev;
> +
> +	if (!mhi_is_active(mhi_cntrl)) {
> +		seq_puts(m, "Device not ready\n");
> +		return -ENODEV;
> +	}
> +
> +	seq_printf(m,
> +		   "Votes: %d\n%s\n", mhi_dev->dev_wake,
> +		   "Usage: echo get/put > device_vote for vote/unvote");
> +
> +	return 0;
> +}
> +
> +static ssize_t mhi_debugfs_device_vote_write(struct file *file,
> +					     const char __user *ubuf,
> +					     size_t count, loff_t *ppos)
> +{
> +	struct seq_file	*m = file->private_data;
> +	struct mhi_controller *mhi_cntrl = m->private;
> +	struct mhi_device *mhi_dev = mhi_cntrl->mhi_dev;
> +	char buf[32];
> +	int ret = -EINVAL;
> +
> +	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
> +		return -EFAULT;
> +
> +	if (!strncmp(buf, "get", 3)) {

Hmm, but the buffer size is 32?

> +		ret = mhi_device_get_sync(mhi_dev);
> +	} else if (!strncmp(buf, "put", 3)) {
> +		mhi_device_put(mhi_dev);
> +		ret = 0;
> +	}
> +
> +	return ret ? ret : count;
> +}
> +
> +static int mhi_debugfs_timeout_ms_show(struct seq_file *m, void *d)
> +{
> +	struct mhi_controller *mhi_cntrl = m->private;
> +
> +	seq_printf(m, "%u ms\n", mhi_cntrl->timeout_ms);
> +
> +	return 0;
> +}
> +
> +static ssize_t mhi_debugfs_timeout_ms_write(struct file *file,
> +					    const char __user *ubuf,
> +					    size_t count, loff_t *ppos)
> +{
> +	struct seq_file	*m = file->private_data;
> +	struct mhi_controller *mhi_cntrl = m->private;
> +	u32 timeout_ms;
> +
> +	if (kstrtou32_from_user(ubuf, count, 0, &timeout_ms))
> +		return -EINVAL;
> +
> +	mhi_cntrl->timeout_ms = timeout_ms;
> +
> +	return count;
> +}
> +
> +static int mhi_debugfs_trigger_reset(void *data, u64 val)

Triggering reset on host or device?

> +{
> +	struct mhi_controller *mhi_cntrl = data;
> +	struct mhi_device *mhi_dev = mhi_cntrl->mhi_dev;
> +	struct device *dev = &mhi_dev->dev;
> +	enum mhi_pm_state cur_state;
> +	int ret = -EIO;
> +
> +	if (!mhi_is_active(mhi_cntrl))
> +		return -ENODEV;
> +
> +	if (!val)
> +		return -EINVAL;
> +
> +	ret = mhi_device_get_sync(mhi_dev);
> +	if (ret) {
> +		dev_err(dev, "Device did not enter M0 state, MHI:%s, PM:%s\n",
> +			TO_MHI_STATE_STR(mhi_cntrl->dev_state),
> +			to_mhi_pm_state_str(mhi_cntrl->pm_state));
> +		return ret;
> +	}
> +
> +	if (mhi_cntrl->rddm_image) {
> +		ret = mhi_force_rddm_mode(mhi_cntrl);
> +		goto exit_mhi_trigger_reset;
> +	}
> +
> +	write_lock_irq(&mhi_cntrl->pm_lock);
> +	cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_SYS_ERR_DETECT);

Looks like in host but how does this resets it?

> +	write_unlock_irq(&mhi_cntrl->pm_lock);
> +
> +	if (cur_state != MHI_PM_SYS_ERR_DETECT)
> +		goto exit_mhi_trigger_reset;

So this condition is also a success? PS: you're not setting ret here.

> +
> +	mhi_pm_sys_err_handler(mhi_cntrl);
> +	ret = 0;
> +
> +exit_mhi_trigger_reset:
> +	mhi_device_put(mhi_dev);
> +
> +	return ret;
> +}
> +
> +static int mhi_debugfs_states_open(struct inode *inode, struct file *fp)
> +{
> +	return single_open(fp, mhi_debugfs_states_show, inode->i_private);
> +}
> +
> +static int mhi_debugfs_events_open(struct inode *inode, struct file *fp)
> +{
> +	return single_open(fp, mhi_debugfs_events_show, inode->i_private);
> +}
> +
> +static int mhi_debugfs_channels_open(struct inode *inode, struct file *fp)
> +{
> +	return single_open(fp, mhi_debugfs_channels_show, inode->i_private);
> +}
> +
> +static int mhi_debugfs_votes_open(struct inode *inode, struct file *fp)
> +{
> +	return single_open(fp, mhi_debugfs_votes_show, inode->i_private);
> +}
> +
> +static int mhi_debugfs_regdump_open(struct inode *inode, struct file *fp)
> +{
> +	return single_open(fp, mhi_debugfs_regdump_show, inode->i_private);
> +}
> +
> +static int mhi_debugfs_device_vote_open(struct inode *inode, struct file *fp)
> +{
> +	return single_open(fp, mhi_debugfs_device_vote_show, inode->i_private);
> +}
> +
> +static int mhi_debugfs_timeout_ms_open(struct inode *inode, struct file *fp)
> +{
> +	return single_open(fp, mhi_debugfs_timeout_ms_show, inode->i_private);
> +}
> +
> +static const struct file_operations debugfs_states_fops = {
> +	.open = mhi_debugfs_states_open,
> +	.release = single_release,
> +	.read = seq_read,
> +};
> +
> +static const struct file_operations debugfs_events_fops = {
> +	.open = mhi_debugfs_events_open,
> +	.release = single_release,
> +	.read = seq_read,
> +};
> +
> +static const struct file_operations debugfs_channels_fops = {
> +	.open = mhi_debugfs_channels_open,
> +	.release = single_release,
> +	.read = seq_read,
> +};
> +
> +static const struct file_operations debugfs_votes_fops = {
> +	.open = mhi_debugfs_votes_open,
> +	.release = single_release,
> +	.read = seq_read,
> +};
> +
> +static const struct file_operations debugfs_regdump_fops = {
> +	.open = mhi_debugfs_regdump_open,
> +	.release = single_release,
> +	.read = seq_read,
> +};
> +
> +static const struct file_operations debugfs_device_vote_fops = {
> +	.open = mhi_debugfs_device_vote_open,
> +	.write = mhi_debugfs_device_vote_write,
> +	.release = single_release,
> +	.read = seq_read,
> +};
> +
> +static const struct file_operations debugfs_timeout_ms_fops = {
> +	.open = mhi_debugfs_timeout_ms_open,
> +	.write = mhi_debugfs_timeout_ms_write,
> +	.release = single_release,
> +	.read = seq_read,
> +};
> +
> +DEFINE_DEBUGFS_ATTRIBUTE(debugfs_reset_fops, NULL,
> +			 mhi_debugfs_trigger_reset, "%llu\n");
> +
> +static struct dentry *mhi_debugfs_root;
> +
> +void mhi_create_debugfs(struct mhi_controller *mhi_cntrl)
> +{
> +	mhi_cntrl->debugfs_dentry =
> +			debugfs_create_dir(dev_name(mhi_cntrl->cntrl_dev),
> +					   mhi_debugfs_root);
> +
> +	debugfs_create_file("states", 0444, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_states_fops);
> +	debugfs_create_file("events", 0444, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_events_fops);
> +	debugfs_create_file("channels", 0444, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_channels_fops);
> +	debugfs_create_file("votes", 0444, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_votes_fops);
> +	debugfs_create_file("regdump", 0444, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_regdump_fops);
> +	debugfs_create_file("device_vote", 0644, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_device_vote_fops);
> +	debugfs_create_file("timeout_ms", 0644, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_timeout_ms_fops);
> +	debugfs_create_file("reset", 0444, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_reset_fops);
> +}
> +
> +void mhi_destroy_debugfs(struct mhi_controller *mhi_cntrl)
> +{
> +	debugfs_remove_recursive(mhi_cntrl->debugfs_dentry);
> +	mhi_cntrl->debugfs_dentry = NULL;
> +}
> +
> +void mhi_debugfs_init(void)
> +{
> +	mhi_debugfs_root = debugfs_create_dir(mhi_bus_type.name, NULL);
> +}
> +
> +void mhi_debugfs_exit(void)
> +{
> +	debugfs_remove_recursive(mhi_debugfs_root);
> +}
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index e2011ec..d2c0f6e 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -4,6 +4,7 @@
>   *
>   */
>  
> +#include <linux/debugfs.h>
>  #include <linux/device.h>
>  #include <linux/dma-direction.h>
>  #include <linux/dma-mapping.h>
> @@ -915,6 +916,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
>  
>  	mhi_cntrl->mhi_dev = mhi_dev;
>  
> +	mhi_create_debugfs(mhi_cntrl);
> +
>  	return 0;
>  
>  error_add_dev:
> @@ -937,6 +940,8 @@ void mhi_unregister_controller(struct mhi_controller *mhi_cntrl)
>  	struct mhi_chan *mhi_chan = mhi_cntrl->mhi_chan;
>  	unsigned int i;
>  
> +	mhi_destroy_debugfs(mhi_cntrl);
> +
>  	kfree(mhi_cntrl->mhi_cmd);
>  	kfree(mhi_cntrl->mhi_event);
>  
> @@ -1284,11 +1289,13 @@ struct bus_type mhi_bus_type = {
>  
>  static int __init mhi_init(void)
>  {
> +	mhi_debugfs_init();
>  	return bus_register(&mhi_bus_type);
>  }
>  
>  static void __exit mhi_exit(void)
>  {
> +	mhi_debugfs_exit();
>  	bus_unregister(&mhi_bus_type);
>  }
>  
> diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
> index 997c6e9..368c442 100644
> --- a/drivers/bus/mhi/core/internal.h
> +++ b/drivers/bus/mhi/core/internal.h
> @@ -570,6 +570,30 @@ struct mhi_chan {
>  /* Default MHI timeout */
>  #define MHI_TIMEOUT_MS (1000)
>  
> +/* debugfs related functions */
> +#ifdef CONFIG_MHI_BUS_DEBUG
> +void mhi_create_debugfs(struct mhi_controller *mhi_cntrl);
> +void mhi_destroy_debugfs(struct mhi_controller *mhi_cntrl);
> +void mhi_debugfs_init(void);
> +void mhi_debugfs_exit(void);
> +#else
> +static inline void mhi_create_debugfs(struct mhi_controller *mhi_cntrl)
> +{
> +}
> +
> +static inline void mhi_destroy_debugfs(struct mhi_controller *mhi_cntrl)
> +{
> +}
> +
> +static inline void mhi_debugfs_init(void)
> +{
> +}
> +
> +static inline void mhi_debugfs_exit(void)
> +{
> +}
> +#endif
> +
>  struct mhi_device *mhi_alloc_device(struct mhi_controller *mhi_cntrl);
>  
>  int mhi_destroy_device(struct device *dev, void *data);
> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> index 74c5cb1..c80d3553 100644
> --- a/drivers/bus/mhi/core/pm.c
> +++ b/drivers/bus/mhi/core/pm.c
> @@ -256,6 +256,7 @@ int mhi_pm_m0_transition(struct mhi_controller *mhi_cntrl)
>  		dev_err(dev, "Unable to transition to M0 state\n");
>  		return -EIO;
>  	}
> +	mhi_cntrl->M0++;

This change shouldn't be part of this patch.

Thanks,
Mani

>  
>  	/* Wake up the device */
>  	read_lock_bh(&mhi_cntrl->pm_lock);
> @@ -326,6 +327,8 @@ void mhi_pm_m1_transition(struct mhi_controller *mhi_cntrl)
>  		mhi_cntrl->dev_state = MHI_STATE_M2;
>  
>  		write_unlock_irq(&mhi_cntrl->pm_lock);
> +
> +		mhi_cntrl->M2++;
>  		wake_up_all(&mhi_cntrl->state_event);
>  
>  		/* If there are any pending resources, exit M2 immediately */
> @@ -362,6 +365,7 @@ int mhi_pm_m3_transition(struct mhi_controller *mhi_cntrl)
>  		return -EIO;
>  	}
>  
> +	mhi_cntrl->M3++;
>  	wake_up_all(&mhi_cntrl->state_event);
>  
>  	return 0;
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index 7ed785e..b1e8b4f 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -288,6 +288,7 @@ struct mhi_controller_config {
>   * @cntrl_dev: Pointer to the struct device of physical bus acting as the MHI
>   *            controller (required)
>   * @mhi_dev: MHI device instance for the controller
> + * @debugfs_dentry: MHI controller debugfs directory
>   * @regs: Base address of MHI MMIO register space (required)
>   * @bhi: Points to base of MHI BHI register space
>   * @bhie: Points to base of MHI BHIe register space
> @@ -326,6 +327,7 @@ struct mhi_controller_config {
>   * @dev_state: MHI device state
>   * @dev_wake: Device wakeup count
>   * @pending_pkts: Pending packets for the controller
> + * @M0, M2, M3, M3_fast: Counters to track number of device MHI state changes
>   * @transition_list: List of MHI state transitions
>   * @transition_lock: Lock for protecting MHI state transition list
>   * @wlock: Lock for protecting device wakeup
> @@ -364,6 +366,7 @@ struct mhi_controller_config {
>  struct mhi_controller {
>  	struct device *cntrl_dev;
>  	struct mhi_device *mhi_dev;
> +	struct dentry *debugfs_dentry;
>  	void __iomem *regs;
>  	void __iomem *bhi;
>  	void __iomem *bhie;
> @@ -405,6 +408,7 @@ struct mhi_controller {
>  	enum mhi_state dev_state;
>  	atomic_t dev_wake;
>  	atomic_t pending_pkts;
> +	u32 M0, M2, M3, M3_fast;
>  	struct list_head transition_list;
>  	spinlock_t transition_lock;
>  	spinlock_t wlock;
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 

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