[PATCH v3 0/3] Debugfs and Sysfs entries for MHI

[PATCH v3 0/3] Debugfs and Sysfs entries for MHI

[Bhaumik Bhatt]

Introduce debugfs and sysfs entries for MHI.
Fixes to allow building MHI as a module without warnings/errors.

This set of patches was tested on arm64 and x86_64 architectures.

v3:
-Fix typo in commit text and add a minor update to it

v2:
-Remove the patch for removal of MODULE_LICENSE() warnings
-Add fixes to adhere to the Kconfig coding style

Bhaumik Bhatt (3):
  bus: mhi: Fix entries based on Kconfig coding style
  bus: mhi: core: Introduce debugfs entries for MHI
  bus: mhi: core: Introduce sysfs entries for MHI

 Documentation/ABI/stable/sysfs-bus-mhi |  21 ++
 MAINTAINERS                            |   1 +
 drivers/bus/mhi/Kconfig                |  20 +-
 drivers/bus/mhi/core/Makefile          |   1 +
 drivers/bus/mhi/core/debugfs.c         | 410 +++++++++++++++++++++++++++++++++
 drivers/bus/mhi/core/init.c            |  60 +++++
 drivers/bus/mhi/core/internal.h        |  24 ++
 include/linux/mhi.h                    |   2 +
 8 files changed, 533 insertions(+), 6 deletions(-)
 create mode 100644 Documentation/ABI/stable/sysfs-bus-mhi
 create mode 100644 drivers/bus/mhi/core/debugfs.c

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v3 1/3] bus: mhi: Fix entries based on Kconfig coding style

[Bhaumik Bhatt]

Kconfig coding style mandates use of tabs for the configuration
definition and an additional two spaces for the help text. Make the
required changes to the MHI Kconfig adhering to those guidelines.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
---
 drivers/bus/mhi/Kconfig | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index a8bd9bd..6677ccc 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -6,9 +6,9 @@
 #
 
 config MHI_BUS
-       tristate "Modem Host Interface (MHI) bus"
-       help
-	 Bus driver for MHI protocol. Modem Host Interface (MHI) is a
-	 communication protocol used by the host processors to control
-	 and communicate with modem devices over a high speed peripheral
-	 bus or shared memory.
+	tristate "Modem Host Interface (MHI) bus"
+	help
+	  Bus driver for MHI protocol. Modem Host Interface (MHI) is a
+	  communication protocol used by the host processors to control
+	  and communicate with modem devices over a high speed peripheral
+	  bus or shared memory.
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v3 1/3] bus: mhi: Fix entries based on Kconfig coding style

[Randy Dunlap]

On 9/18/20 12:39 PM, Bhaumik Bhatt wrote:
> Kconfig coding style mandates use of tabs for the configuration
> definition and an additional two spaces for the help text. Make the
> required changes to the MHI Kconfig adhering to those guidelines.
> 
> Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>

Acked-by: Randy Dunlap <rdunlap@infradead.org>

Thanks.

> ---
>  drivers/bus/mhi/Kconfig | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
> index a8bd9bd..6677ccc 100644
> --- a/drivers/bus/mhi/Kconfig
> +++ b/drivers/bus/mhi/Kconfig
> @@ -6,9 +6,9 @@
>  #
>  
>  config MHI_BUS
> -       tristate "Modem Host Interface (MHI) bus"
> -       help
> -	 Bus driver for MHI protocol. Modem Host Interface (MHI) is a
> -	 communication protocol used by the host processors to control
> -	 and communicate with modem devices over a high speed peripheral
> -	 bus or shared memory.
> +	tristate "Modem Host Interface (MHI) bus"
> +	help
> +	  Bus driver for MHI protocol. Modem Host Interface (MHI) is a
> +	  communication protocol used by the host processors to control
> +	  and communicate with modem devices over a high speed peripheral
> +	  bus or shared memory.
> 


-- 
~Randy

Re: [PATCH v3 1/3] bus: mhi: Fix entries based on Kconfig coding style

[Manivannan Sadhasivam]

On Fri, Sep 18, 2020 at 12:39:50PM -0700, Bhaumik Bhatt wrote:
> Kconfig coding style mandates use of tabs for the configuration
> definition and an additional two spaces for the help text. Make the
> required changes to the MHI Kconfig adhering to those guidelines.
> 
> Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Thanks,
Mani

> ---
>  drivers/bus/mhi/Kconfig | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
> index a8bd9bd..6677ccc 100644
> --- a/drivers/bus/mhi/Kconfig
> +++ b/drivers/bus/mhi/Kconfig
> @@ -6,9 +6,9 @@
>  #
>  
>  config MHI_BUS
> -       tristate "Modem Host Interface (MHI) bus"
> -       help
> -	 Bus driver for MHI protocol. Modem Host Interface (MHI) is a
> -	 communication protocol used by the host processors to control
> -	 and communicate with modem devices over a high speed peripheral
> -	 bus or shared memory.
> +	tristate "Modem Host Interface (MHI) bus"
> +	help
> +	  Bus driver for MHI protocol. Modem Host Interface (MHI) is a
> +	  communication protocol used by the host processors to control
> +	  and communicate with modem devices over a high speed peripheral
> +	  bus or shared memory.
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 

[PATCH v3 2/3] bus: mhi: core: Introduce debugfs entries for MHI

[Bhaumik Bhatt]

Introduce debugfs entries to show state, register, channel, device,
and event rings information. Allow the host to dump registers,
issue device wake, and change the MHI timeout to help in debug.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
---
 drivers/bus/mhi/Kconfig         |   8 +
 drivers/bus/mhi/core/Makefile   |   1 +
 drivers/bus/mhi/core/debugfs.c  | 410 ++++++++++++++++++++++++++++++++++++++++
 drivers/bus/mhi/core/init.c     |   7 +
 drivers/bus/mhi/core/internal.h |  24 +++
 include/linux/mhi.h             |   2 +
 6 files changed, 452 insertions(+)
 create mode 100644 drivers/bus/mhi/core/debugfs.c

diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index 6677ccc..e841c10 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..12c57ab3 100644
--- a/drivers/bus/mhi/core/Makefile
+++ b/drivers/bus/mhi/core/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_MHI_BUS) := mhi.o
 
 mhi-y := init.o main.o pm.o boot.o
+mhi-$(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..53d05a8
--- /dev/null
+++ b/drivers/bus/mhi/core/debugfs.c
@@ -0,0 +1,410 @@
+// 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 <linux/module.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");
+
+	/* counters */
+	seq_printf(m, "M0: %u M2: %u M3: %u", mhi_cntrl->M0, mhi_cntrl->M2,
+		   mhi_cntrl->M3);
+
+	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", er_ctxt->rp,
+			   er_ctxt->wp);
+
+		seq_printf(m, " local rp: 0x%llx db: 0x%llx\n", (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_info_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: type: %s dev_wake: %u",
+		   mhi_dev->name, mhi_dev->dev_type ? "Controller" : "Transfer",
+		   mhi_dev->dev_wake);
+
+	/* for transfer device types only */
+	if (mhi_dev->dev_type == MHI_DEVICE_XFER)
+		seq_printf((struct seq_file *)data, " channels: %u(UL)/%u(DL)",
+			   mhi_dev->ul_chan_id, mhi_dev->dl_chan_id);
+
+	seq_puts((struct seq_file *)data, "\n");
+
+	return 0;
+}
+
+static int mhi_debugfs_devices_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_info_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;
+	} regs[] = {
+		{ "MHI_REGLEN", MHIREGLEN, mhi_base},
+		{ "MHI_VER", MHIVER, mhi_base},
+		{ "MHI_CFG", MHICFG, mhi_base},
+		{ "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; regs[i].name; i++) {
+		if (!regs[i].base)
+			continue;
+		ret = mhi_read_reg(mhi_cntrl, regs[i].base, regs[i].offset,
+				   &val);
+		if (ret)
+			continue;
+
+		seq_printf(m, "%s: 0x%x\n", regs[i].name, val);
+	}
+
+	return 0;
+}
+
+static int mhi_debugfs_device_wake_show(struct seq_file *m, void *d)
+{
+	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,
+		   "Wake count: %d\n%s\n", mhi_dev->dev_wake,
+		   "Usage: echo get/put > device_wake to vote/unvote for M0");
+
+	return 0;
+}
+
+static ssize_t mhi_debugfs_device_wake_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[16];
+	int ret = -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+		return -EFAULT;
+
+	if (!strncmp(buf, "get", 3)) {
+		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_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_devices_open(struct inode *inode, struct file *fp)
+{
+	return single_open(fp, mhi_debugfs_devices_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_wake_open(struct inode *inode, struct file *fp)
+{
+	return single_open(fp, mhi_debugfs_device_wake_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_devices_fops = {
+	.open = mhi_debugfs_devices_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_wake_fops = {
+	.open = mhi_debugfs_device_wake_open,
+	.write = mhi_debugfs_device_wake_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,
+};
+
+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("devices", 0444, mhi_cntrl->debugfs_dentry,
+			    mhi_cntrl, &debugfs_devices_fops);
+	debugfs_create_file("regdump", 0444, mhi_cntrl->debugfs_dentry,
+			    mhi_cntrl, &debugfs_regdump_fops);
+	debugfs_create_file("device_wake", 0644, mhi_cntrl->debugfs_dentry,
+			    mhi_cntrl, &debugfs_device_wake_fops);
+	debugfs_create_file("timeout_ms", 0644, mhi_cntrl->debugfs_dentry,
+			    mhi_cntrl, &debugfs_timeout_ms_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 d232938..61e5885 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);
 
@@ -1300,11 +1305,13 @@ 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 5a81a42..7989269 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/include/linux/mhi.h b/include/linux/mhi.h
index 008b8f6..fb45a0f 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -291,6 +291,7 @@ 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
@@ -370,6 +371,7 @@ 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;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v3 2/3] bus: mhi: core: Introduce debugfs entries for MHI

[Manivannan Sadhasivam]

On Fri, Sep 18, 2020 at 12:39:51PM -0700, Bhaumik Bhatt wrote:
> Introduce debugfs entries to show state, register, channel, device,
> and event rings information. Allow the host to dump registers,
> issue device wake, and change the MHI timeout to help in debug.
> 
> Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

PS: I've reviewed this and the debugfs patch before. Please keep the tags
while posting incremental patchset.

Thanks,
Mani

> ---
>  drivers/bus/mhi/Kconfig         |   8 +
>  drivers/bus/mhi/core/Makefile   |   1 +
>  drivers/bus/mhi/core/debugfs.c  | 410 ++++++++++++++++++++++++++++++++++++++++
>  drivers/bus/mhi/core/init.c     |   7 +
>  drivers/bus/mhi/core/internal.h |  24 +++
>  include/linux/mhi.h             |   2 +
>  6 files changed, 452 insertions(+)
>  create mode 100644 drivers/bus/mhi/core/debugfs.c
> 
> diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
> index 6677ccc..e841c10 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..12c57ab3 100644
> --- a/drivers/bus/mhi/core/Makefile
> +++ b/drivers/bus/mhi/core/Makefile
> @@ -1,3 +1,4 @@
>  obj-$(CONFIG_MHI_BUS) := mhi.o
>  
>  mhi-y := init.o main.o pm.o boot.o
> +mhi-$(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..53d05a8
> --- /dev/null
> +++ b/drivers/bus/mhi/core/debugfs.c
> @@ -0,0 +1,410 @@
> +// 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 <linux/module.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");
> +
> +	/* counters */
> +	seq_printf(m, "M0: %u M2: %u M3: %u", mhi_cntrl->M0, mhi_cntrl->M2,
> +		   mhi_cntrl->M3);
> +
> +	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", er_ctxt->rp,
> +			   er_ctxt->wp);
> +
> +		seq_printf(m, " local rp: 0x%llx db: 0x%llx\n", (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_info_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: type: %s dev_wake: %u",
> +		   mhi_dev->name, mhi_dev->dev_type ? "Controller" : "Transfer",
> +		   mhi_dev->dev_wake);
> +
> +	/* for transfer device types only */
> +	if (mhi_dev->dev_type == MHI_DEVICE_XFER)
> +		seq_printf((struct seq_file *)data, " channels: %u(UL)/%u(DL)",
> +			   mhi_dev->ul_chan_id, mhi_dev->dl_chan_id);
> +
> +	seq_puts((struct seq_file *)data, "\n");
> +
> +	return 0;
> +}
> +
> +static int mhi_debugfs_devices_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_info_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;
> +	} regs[] = {
> +		{ "MHI_REGLEN", MHIREGLEN, mhi_base},
> +		{ "MHI_VER", MHIVER, mhi_base},
> +		{ "MHI_CFG", MHICFG, mhi_base},
> +		{ "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; regs[i].name; i++) {
> +		if (!regs[i].base)
> +			continue;
> +		ret = mhi_read_reg(mhi_cntrl, regs[i].base, regs[i].offset,
> +				   &val);
> +		if (ret)
> +			continue;
> +
> +		seq_printf(m, "%s: 0x%x\n", regs[i].name, val);
> +	}
> +
> +	return 0;
> +}
> +
> +static int mhi_debugfs_device_wake_show(struct seq_file *m, void *d)
> +{
> +	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,
> +		   "Wake count: %d\n%s\n", mhi_dev->dev_wake,
> +		   "Usage: echo get/put > device_wake to vote/unvote for M0");
> +
> +	return 0;
> +}
> +
> +static ssize_t mhi_debugfs_device_wake_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[16];
> +	int ret = -EINVAL;
> +
> +	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
> +		return -EFAULT;
> +
> +	if (!strncmp(buf, "get", 3)) {
> +		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_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_devices_open(struct inode *inode, struct file *fp)
> +{
> +	return single_open(fp, mhi_debugfs_devices_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_wake_open(struct inode *inode, struct file *fp)
> +{
> +	return single_open(fp, mhi_debugfs_device_wake_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_devices_fops = {
> +	.open = mhi_debugfs_devices_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_wake_fops = {
> +	.open = mhi_debugfs_device_wake_open,
> +	.write = mhi_debugfs_device_wake_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,
> +};
> +
> +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("devices", 0444, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_devices_fops);
> +	debugfs_create_file("regdump", 0444, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_regdump_fops);
> +	debugfs_create_file("device_wake", 0644, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_device_wake_fops);
> +	debugfs_create_file("timeout_ms", 0644, mhi_cntrl->debugfs_dentry,
> +			    mhi_cntrl, &debugfs_timeout_ms_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 d232938..61e5885 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);
>  
> @@ -1300,11 +1305,13 @@ 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 5a81a42..7989269 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/include/linux/mhi.h b/include/linux/mhi.h
> index 008b8f6..fb45a0f 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -291,6 +291,7 @@ 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
> @@ -370,6 +371,7 @@ 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;
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 

[PATCH v3 3/3] bus: mhi: core: Introduce sysfs entries for MHI

[Bhaumik Bhatt]

Introduce sysfs entries to enable userspace clients the ability to read
the serial number and the OEM PK Hash values obtained from BHI. OEMs
need to read these device-specific hardware information values through
userspace for factory testing purposes and cannot be exposed via degbufs
as it may remain disabled for performance reasons. Also, update the
documentation for ABI to include these entries.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
---
 Documentation/ABI/stable/sysfs-bus-mhi | 21 ++++++++++++++
 MAINTAINERS                            |  1 +
 drivers/bus/mhi/core/init.c            | 53 ++++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+)
 create mode 100644 Documentation/ABI/stable/sysfs-bus-mhi

diff --git a/Documentation/ABI/stable/sysfs-bus-mhi b/Documentation/ABI/stable/sysfs-bus-mhi
new file mode 100644
index 0000000..ecfe766
--- /dev/null
+++ b/Documentation/ABI/stable/sysfs-bus-mhi
@@ -0,0 +1,21 @@
+What:		/sys/bus/mhi/devices/.../serialnumber
+Date:		Sept 2020
+KernelVersion:	5.10
+Contact:	Bhaumik Bhatt <bbhatt@codeaurora.org>
+Description:	The file holds the serial number of the client device obtained
+		using a BHI (Boot Host Interface) register read after at least
+		one attempt to power up the device has been done. If read
+		without having the device power on at least once, the file will
+		read all 0's.
+Users:		Any userspace application or clients interested in device info.
+
+What:		/sys/bus/mhi/devices/.../oem_pk_hash
+Date:		Sept 2020
+KernelVersion:	5.10
+Contact:	Bhaumik Bhatt <bbhatt@codeaurora.org>
+Description:	The file holds the OEM PK Hash value of the endpoint device
+		obtained using a BHI (Boot Host Interface) register read after
+		at least one attempt to power up the device has been done. If
+		read without having the device power on at least once, the file
+		will read all 0's.
+Users:		Any userspace application or clients interested in device info.
diff --git a/MAINTAINERS b/MAINTAINERS
index deaafb6..11e7be9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11323,6 +11323,7 @@ M:	Hemant Kumar <hemantk@codeaurora.org>
 L:	linux-arm-msm@vger.kernel.org
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mani/mhi.git
+F:	Documentation/ABI/stable/sysfs-bus-mhi
 F:	Documentation/mhi/
 F:	drivers/bus/mhi/
 F:	include/linux/mhi.h
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 61e5885..1b4161e 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -76,6 +76,56 @@ const char *to_mhi_pm_state_str(enum mhi_pm_state state)
 	return mhi_pm_state_str[index];
 }
 
+static ssize_t serial_number_show(struct device *dev,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	struct mhi_device *mhi_dev = to_mhi_device(dev);
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+
+	return snprintf(buf, PAGE_SIZE, "Serial Number: %u\n",
+			mhi_cntrl->serial_number);
+}
+static DEVICE_ATTR_RO(serial_number);
+
+static ssize_t oem_pk_hash_show(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	struct mhi_device *mhi_dev = to_mhi_device(dev);
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+	int i, cnt = 0;
+
+	for (i = 0; i < ARRAY_SIZE(mhi_cntrl->oem_pk_hash); i++)
+		cnt += snprintf(buf + cnt, PAGE_SIZE - cnt,
+				"OEMPKHASH[%d]: 0x%x\n", i,
+				mhi_cntrl->oem_pk_hash[i]);
+
+	return cnt;
+}
+static DEVICE_ATTR_RO(oem_pk_hash);
+
+static struct attribute *mhi_sysfs_attrs[] = {
+	&dev_attr_serial_number.attr,
+	&dev_attr_oem_pk_hash.attr,
+	NULL,
+};
+
+static const struct attribute_group mhi_sysfs_group = {
+	.attrs = mhi_sysfs_attrs,
+};
+
+static int mhi_create_sysfs(struct mhi_controller *mhi_cntrl)
+{
+	return sysfs_create_group(&mhi_cntrl->mhi_dev->dev.kobj,
+				  &mhi_sysfs_group);
+}
+
+static void mhi_destroy_sysfs(struct mhi_controller *mhi_cntrl)
+{
+	sysfs_remove_group(&mhi_cntrl->mhi_dev->dev.kobj, &mhi_sysfs_group);
+}
+
 /* MHI protocol requires the transfer ring to be aligned with ring length */
 static int mhi_alloc_aligned_ring(struct mhi_controller *mhi_cntrl,
 				  struct mhi_ring *ring,
@@ -917,6 +967,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 	mhi_cntrl->mhi_dev = mhi_dev;
 
 	mhi_create_debugfs(mhi_cntrl);
+	if (mhi_create_sysfs(mhi_cntrl))
+		dev_err(mhi_cntrl->cntrl_dev, "Failed to create sysfs entries\n");
 
 	return 0;
 
@@ -940,6 +992,7 @@ void mhi_unregister_controller(struct mhi_controller *mhi_cntrl)
 	struct mhi_chan *mhi_chan = mhi_cntrl->mhi_chan;
 	unsigned int i;
 
+	mhi_destroy_sysfs(mhi_cntrl);
 	mhi_destroy_debugfs(mhi_cntrl);
 
 	kfree(mhi_cntrl->mhi_cmd);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v3 3/3] bus: mhi: core: Introduce sysfs entries for MHI

[Manivannan Sadhasivam]

On Fri, Sep 18, 2020 at 12:39:52PM -0700, Bhaumik Bhatt wrote:
> Introduce sysfs entries to enable userspace clients the ability to read
> the serial number and the OEM PK Hash values obtained from BHI. OEMs
> need to read these device-specific hardware information values through
> userspace for factory testing purposes and cannot be exposed via degbufs
> as it may remain disabled for performance reasons. Also, update the
> documentation for ABI to include these entries.
> 
> Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Thanks,
Mani

> ---
>  Documentation/ABI/stable/sysfs-bus-mhi | 21 ++++++++++++++
>  MAINTAINERS                            |  1 +
>  drivers/bus/mhi/core/init.c            | 53 ++++++++++++++++++++++++++++++++++
>  3 files changed, 75 insertions(+)
>  create mode 100644 Documentation/ABI/stable/sysfs-bus-mhi
> 
> diff --git a/Documentation/ABI/stable/sysfs-bus-mhi b/Documentation/ABI/stable/sysfs-bus-mhi
> new file mode 100644
> index 0000000..ecfe766
> --- /dev/null
> +++ b/Documentation/ABI/stable/sysfs-bus-mhi
> @@ -0,0 +1,21 @@
> +What:		/sys/bus/mhi/devices/.../serialnumber
> +Date:		Sept 2020
> +KernelVersion:	5.10
> +Contact:	Bhaumik Bhatt <bbhatt@codeaurora.org>
> +Description:	The file holds the serial number of the client device obtained
> +		using a BHI (Boot Host Interface) register read after at least
> +		one attempt to power up the device has been done. If read
> +		without having the device power on at least once, the file will
> +		read all 0's.
> +Users:		Any userspace application or clients interested in device info.
> +
> +What:		/sys/bus/mhi/devices/.../oem_pk_hash
> +Date:		Sept 2020
> +KernelVersion:	5.10
> +Contact:	Bhaumik Bhatt <bbhatt@codeaurora.org>
> +Description:	The file holds the OEM PK Hash value of the endpoint device
> +		obtained using a BHI (Boot Host Interface) register read after
> +		at least one attempt to power up the device has been done. If
> +		read without having the device power on at least once, the file
> +		will read all 0's.
> +Users:		Any userspace application or clients interested in device info.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index deaafb6..11e7be9 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11323,6 +11323,7 @@ M:	Hemant Kumar <hemantk@codeaurora.org>
>  L:	linux-arm-msm@vger.kernel.org
>  S:	Maintained
>  T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mani/mhi.git
> +F:	Documentation/ABI/stable/sysfs-bus-mhi
>  F:	Documentation/mhi/
>  F:	drivers/bus/mhi/
>  F:	include/linux/mhi.h
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index 61e5885..1b4161e 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -76,6 +76,56 @@ const char *to_mhi_pm_state_str(enum mhi_pm_state state)
>  	return mhi_pm_state_str[index];
>  }
>  
> +static ssize_t serial_number_show(struct device *dev,
> +				  struct device_attribute *attr,
> +				  char *buf)
> +{
> +	struct mhi_device *mhi_dev = to_mhi_device(dev);
> +	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
> +
> +	return snprintf(buf, PAGE_SIZE, "Serial Number: %u\n",
> +			mhi_cntrl->serial_number);
> +}
> +static DEVICE_ATTR_RO(serial_number);
> +
> +static ssize_t oem_pk_hash_show(struct device *dev,
> +				struct device_attribute *attr,
> +				char *buf)
> +{
> +	struct mhi_device *mhi_dev = to_mhi_device(dev);
> +	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
> +	int i, cnt = 0;
> +
> +	for (i = 0; i < ARRAY_SIZE(mhi_cntrl->oem_pk_hash); i++)
> +		cnt += snprintf(buf + cnt, PAGE_SIZE - cnt,
> +				"OEMPKHASH[%d]: 0x%x\n", i,
> +				mhi_cntrl->oem_pk_hash[i]);
> +
> +	return cnt;
> +}
> +static DEVICE_ATTR_RO(oem_pk_hash);
> +
> +static struct attribute *mhi_sysfs_attrs[] = {
> +	&dev_attr_serial_number.attr,
> +	&dev_attr_oem_pk_hash.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group mhi_sysfs_group = {
> +	.attrs = mhi_sysfs_attrs,
> +};
> +
> +static int mhi_create_sysfs(struct mhi_controller *mhi_cntrl)
> +{
> +	return sysfs_create_group(&mhi_cntrl->mhi_dev->dev.kobj,
> +				  &mhi_sysfs_group);
> +}
> +
> +static void mhi_destroy_sysfs(struct mhi_controller *mhi_cntrl)
> +{
> +	sysfs_remove_group(&mhi_cntrl->mhi_dev->dev.kobj, &mhi_sysfs_group);
> +}
> +
>  /* MHI protocol requires the transfer ring to be aligned with ring length */
>  static int mhi_alloc_aligned_ring(struct mhi_controller *mhi_cntrl,
>  				  struct mhi_ring *ring,
> @@ -917,6 +967,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
>  	mhi_cntrl->mhi_dev = mhi_dev;
>  
>  	mhi_create_debugfs(mhi_cntrl);
> +	if (mhi_create_sysfs(mhi_cntrl))
> +		dev_err(mhi_cntrl->cntrl_dev, "Failed to create sysfs entries\n");
>  
>  	return 0;
>  
> @@ -940,6 +992,7 @@ void mhi_unregister_controller(struct mhi_controller *mhi_cntrl)
>  	struct mhi_chan *mhi_chan = mhi_cntrl->mhi_chan;
>  	unsigned int i;
>  
> +	mhi_destroy_sysfs(mhi_cntrl);
>  	mhi_destroy_debugfs(mhi_cntrl);
>  
>  	kfree(mhi_cntrl->mhi_cmd);
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 

Re: [PATCH v3 0/3] Debugfs and Sysfs entries for MHI

[Manivannan Sadhasivam]

On Fri, Sep 18, 2020 at 12:39:49PM -0700, Bhaumik Bhatt wrote:
> Introduce debugfs and sysfs entries for MHI.
> Fixes to allow building MHI as a module without warnings/errors.
> 
> This set of patches was tested on arm64 and x86_64 architectures.
> 
> v3:
> -Fix typo in commit text and add a minor update to it
> 

Series applied to mhi-next!

Thanks,
Mani

> v2:
> -Remove the patch for removal of MODULE_LICENSE() warnings
> -Add fixes to adhere to the Kconfig coding style
> 
> Bhaumik Bhatt (3):
>   bus: mhi: Fix entries based on Kconfig coding style
>   bus: mhi: core: Introduce debugfs entries for MHI
>   bus: mhi: core: Introduce sysfs entries for MHI
> 
>  Documentation/ABI/stable/sysfs-bus-mhi |  21 ++
>  MAINTAINERS                            |   1 +
>  drivers/bus/mhi/Kconfig                |  20 +-
>  drivers/bus/mhi/core/Makefile          |   1 +
>  drivers/bus/mhi/core/debugfs.c         | 410 +++++++++++++++++++++++++++++++++
>  drivers/bus/mhi/core/init.c            |  60 +++++
>  drivers/bus/mhi/core/internal.h        |  24 ++
>  include/linux/mhi.h                    |   2 +
>  8 files changed, 533 insertions(+), 6 deletions(-)
>  create mode 100644 Documentation/ABI/stable/sysfs-bus-mhi
>  create mode 100644 drivers/bus/mhi/core/debugfs.c
> 
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>