Commit 21cb9b18 authored by Bhaumik Bhatt's avatar Bhaumik Bhatt Committed by Greg Kroah-Hartman
Browse files

bus: mhi: core: Introduce sysfs entries for MHI 



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.

Reviewed-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
[mani: used dev_groups to manage sysfs attributes]
Signed-off-by: default avatarBhaumik Bhatt <bbhatt@codeaurora.org>
Signed-off-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200929175218.8178-16-manivannan.sadhasivam@linaro.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c7bd825e

Documentation/ABI/stable/sysfs-bus-mhi

0 → 100644
+21 −0
Original line number Diff line number Diff line 
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.

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -11364,6 +11364,7 @@ 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

drivers/bus/mhi/core/init.c

+37 −0
Original line number Diff line number Diff line
@@ -76,6 +76,42 @@ 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_dev_attrs[] = {

	&dev_attr_serial_number.attr,

	&dev_attr_oem_pk_hash.attr,

	NULL,

};

ATTRIBUTE_GROUPS(mhi_dev);



/* 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,
@@ -1301,6 +1337,7 @@ struct bus_type mhi_bus_type = { 
	.dev_name = "mhi",

	.match = mhi_match,

	.uevent = mhi_uevent,

	.dev_groups = mhi_dev_groups,

};



static int __init mhi_init(void)

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