[v3,3/3] bus: mhi: core: Introduce sysfs entries for MHI
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Message ID 1600457992-18448-4-git-send-email-bbhatt@codeaurora.org
State In Next
Commit 1a5042b7edfd0b79f1036e1a4407b1ed229f8215
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Series
  • Debugfs and Sysfs entries for MHI
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Commit Message

Bhaumik Bhatt Sept. 18, 2020, 7:39 p.m. UTC
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

Comments

Manivannan Sadhasivam Sept. 21, 2020, 1:58 p.m. UTC | #1
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
>

Patch
diff mbox series

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);