[PATCH v4] scsi: ufs: Make sysfs attributes writable

From: Evan Green
Date: Wed Aug 08 2018 - 18:45:08 EST

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This change makes the UFS controller's sysfs attributes writable, which
will enable users to provision unprovisioned UFS devices, or
re-provision unlocked UFS devices.

Signed-off-by: Evan Green <evgreen@xxxxxxxxxxxx>
---
Changes since v3:
- Added static to UFS_ATTRIBUTE_RO [Stanislav]
- Fixed read-only exception_event_status [Stanislav]
- Added warnings in documentation for write-once
attributes [Stanislav]

Configfs was determined to be the preferred mechanism for writing the
config descriptor, but attributes also need to be written during setup,
and are already present in sysfs. Making these attributes writable is
also helpful for debugging and experimentation.

Changes since v2:
- Removed the configuration descriptor changes from the series,
since configfs was the preferred way to write to that, leaving only
this change.

Changes since v1:
- Reworked the interface to show each unit of the config
descriptor as a separate directory, rather than the previous method I
had of a file for selecting the unit, and then a common set of files
that interacted with whichever unit was selected. I did some kobject
magic to accomplish this. I noticed from Greg KH's reply to Sayali's
patches [1] that configfs might be the preferred method. Let me know
if I should abandon this series in favor of Sayali's, with the
possible exception of "Make sysfs attributes writable".
- Squashed documentation changes into their respective code
changes.
- I decided to keep the config descriptor attributes as their
own files, rather than hiding writes behind device descriptor and unit
descriptor, as I think that's more future proof and true to the UFS spec.

[1] https://lkml.org/lkml/2018/6/8/210

Documentation/ABI/testing/sysfs-driver-ufs | 29 +++++++---------
drivers/scsi/ufs/ufs-sysfs.c | 56 ++++++++++++++++++++----------
2 files changed, 51 insertions(+), 34 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs
index 016724ec26d5..3ed8aaac2faf 100644
--- a/Documentation/ABI/testing/sysfs-driver-ufs
+++ b/Documentation/ABI/testing/sysfs-driver-ufs
@@ -685,7 +685,6 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file provides the boot lun enabled UFS device attribute.
The full information about the attribute could be found at
UFS specifications 2.1.
- The file is read only.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/current_power_mode
Date: February 2018
@@ -693,7 +692,6 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file provides the current power mode UFS device attribute.
The full information about the attribute could be found at
UFS specifications 2.1.
- The file is read only.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/active_icc_level
Date: February 2018
@@ -701,7 +699,6 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file provides the active icc level UFS device attribute.
The full information about the attribute could be found at
UFS specifications 2.1.
- The file is read only.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/ooo_data_enabled
Date: February 2018
@@ -709,7 +706,9 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file provides the out of order data transfer enabled UFS
device attribute. The full information about the attribute
could be found at UFS specifications 2.1.
- The file is read only.
+ Warning: This attribute can only be written one time
+ within the lifetime of the device. Once written, it cannot be
+ changed.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/bkops_status
Date: February 2018
@@ -717,7 +716,6 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file provides the background operations status UFS device
attribute. The full information about the attribute could
be found at UFS specifications 2.1.
- The file is read only.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/purge_status
Date: February 2018
@@ -725,7 +723,9 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file provides the purge operation status UFS device
attribute. The full information about the attribute could
be found at UFS specifications 2.1.
- The file is read only.
+ Warning: This attribute can only be written one time
+ within the lifetime of the device. Once written, it cannot be
+ changed.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/max_data_in_size
Date: February 2018
@@ -733,7 +733,6 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file shows the maximum data size in a DATA IN
UPIU. The full information about the attribute could
be found at UFS specifications 2.1.
- The file is read only.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/max_data_out_size
Date: February 2018
@@ -741,7 +740,6 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file shows the maximum number of bytes that can be
requested with a READY TO TRANSFER UPIU. The full information
about the attribute could be found at UFS specifications 2.1.
- The file is read only.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/reference_clock_frequency
Date: February 2018
@@ -749,14 +747,19 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file provides the reference clock frequency UFS device
attribute. The full information about the attribute could
be found at UFS specifications 2.1.
- The file is read only.
+ Warning: This attribute can only be written one time
+ within the lifetime of the device. Once written, it cannot be
+ changed.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/configuration_descriptor_lock
Date: February 2018
Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file shows whether the configuration descriptor is locked.
The full information about the attribute could be found at
- UFS specifications 2.1. The file is read only.
+ UFS specifications 2.1.
+ Warning: This attribute can only be written one time
+ within the lifetime of the device. Once written, it cannot be
+ changed.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/max_number_of_rtt
Date: February 2018
@@ -765,7 +768,6 @@ Description: This file provides the maximum current number of
outstanding RTTs in device that is allowed. The full
information about the attribute could be found at
UFS specifications 2.1.
- The file is read only.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/exception_event_control
Date: February 2018
@@ -773,7 +775,6 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file provides the exception event control UFS device
attribute. The full information about the attribute could
be found at UFS specifications 2.1.
- The file is read only.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/exception_event_status
Date: February 2018
@@ -781,7 +782,6 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file provides the exception event status UFS device
attribute. The full information about the attribute could
be found at UFS specifications 2.1.
- The file is read only.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/ffu_status
Date: February 2018
@@ -789,14 +789,12 @@ Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file provides the ffu status UFS device attribute.
The full information about the attribute could be found at
UFS specifications 2.1.
- The file is read only.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/psa_state
Date: February 2018
Contact: Stanislav Nijnikov <stanislav.nijnikov@xxxxxxx>
Description: This file show the PSA feature status. The full information
about the attribute could be found at UFS specifications 2.1.
- The file is read only.

What: /sys/bus/platform/drivers/ufshcd/*/attributes/psa_data_size
Date: February 2018
@@ -805,7 +803,6 @@ Description: This file shows the amount of data that the host plans to
load to all logical units in pre-soldering state.
The full information about the attribute could be found at
UFS specifications 2.1.
- The file is read only.

What: /sys/class/scsi_device/*/device/dyn_cap_needed
diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index 8d9332bb7d0c..344f5025bc36 100644
--- a/drivers/scsi/ufs/ufs-sysfs.c
+++ b/drivers/scsi/ufs/ufs-sysfs.c
@@ -655,7 +655,7 @@ static const struct attribute_group ufs_sysfs_flags_group = {
.attrs = ufs_sysfs_device_flags,
};

-#define UFS_ATTRIBUTE(_name, _uname) \
+#define UFS_ATTRIBUTE_SHOW(_name, _uname) \
static ssize_t _name##_show(struct device *dev, \
struct device_attribute *attr, char *buf) \
{ \
@@ -665,25 +665,45 @@ static ssize_t _name##_show(struct device *dev, \
QUERY_ATTR_IDN##_uname, 0, 0, &value)) \
return -EINVAL; \
return sprintf(buf, "0x%08X\n", value); \
-} \
+}
+
+#define UFS_ATTRIBUTE_RO(_name, _uname) \
+UFS_ATTRIBUTE_SHOW(_name, _uname) \
static DEVICE_ATTR_RO(_name)

-UFS_ATTRIBUTE(boot_lun_enabled, _BOOT_LU_EN);
-UFS_ATTRIBUTE(current_power_mode, _POWER_MODE);
-UFS_ATTRIBUTE(active_icc_level, _ACTIVE_ICC_LVL);
-UFS_ATTRIBUTE(ooo_data_enabled, _OOO_DATA_EN);
-UFS_ATTRIBUTE(bkops_status, _BKOPS_STATUS);
-UFS_ATTRIBUTE(purge_status, _PURGE_STATUS);
-UFS_ATTRIBUTE(max_data_in_size, _MAX_DATA_IN);
-UFS_ATTRIBUTE(max_data_out_size, _MAX_DATA_OUT);
-UFS_ATTRIBUTE(reference_clock_frequency, _REF_CLK_FREQ);
-UFS_ATTRIBUTE(configuration_descriptor_lock, _CONF_DESC_LOCK);
-UFS_ATTRIBUTE(max_number_of_rtt, _MAX_NUM_OF_RTT);
-UFS_ATTRIBUTE(exception_event_control, _EE_CONTROL);
-UFS_ATTRIBUTE(exception_event_status, _EE_STATUS);
-UFS_ATTRIBUTE(ffu_status, _FFU_STATUS);
-UFS_ATTRIBUTE(psa_state, _PSA_STATE);
-UFS_ATTRIBUTE(psa_data_size, _PSA_DATA_SIZE);
+#define UFS_ATTRIBUTE_RW(_name, _uname) \
+UFS_ATTRIBUTE_SHOW(_name, _uname) \
+static ssize_t _name##_store(struct device *dev, \
+ struct device_attribute *attr, const char *buf, \
+ size_t count) \
+{ \
+ struct ufs_hba *hba = dev_get_drvdata(dev); \
+ u32 value; \
+ if (kstrtou32(buf, 0, &value)) \
+ return -EINVAL; \
+ if (ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_WRITE_ATTR, \
+ QUERY_ATTR_IDN##_uname, 0, 0, &value)) \
+ return -EINVAL; \
+ return count; \
+} \
+static DEVICE_ATTR_RW(_name)
+
+UFS_ATTRIBUTE_RW(boot_lun_enabled, _BOOT_LU_EN);
+UFS_ATTRIBUTE_RO(current_power_mode, _POWER_MODE);
+UFS_ATTRIBUTE_RW(active_icc_level, _ACTIVE_ICC_LVL);
+UFS_ATTRIBUTE_RW(ooo_data_enabled, _OOO_DATA_EN);
+UFS_ATTRIBUTE_RO(bkops_status, _BKOPS_STATUS);
+UFS_ATTRIBUTE_RO(purge_status, _PURGE_STATUS);
+UFS_ATTRIBUTE_RW(max_data_in_size, _MAX_DATA_IN);
+UFS_ATTRIBUTE_RW(max_data_out_size, _MAX_DATA_OUT);
+UFS_ATTRIBUTE_RW(reference_clock_frequency, _REF_CLK_FREQ);
+UFS_ATTRIBUTE_RW(configuration_descriptor_lock, _CONF_DESC_LOCK);
+UFS_ATTRIBUTE_RW(max_number_of_rtt, _MAX_NUM_OF_RTT);
+UFS_ATTRIBUTE_RW(exception_event_control, _EE_CONTROL);
+UFS_ATTRIBUTE_RO(exception_event_status, _EE_STATUS);
+UFS_ATTRIBUTE_RO(ffu_status, _FFU_STATUS);
+UFS_ATTRIBUTE_RO(psa_state, _PSA_STATE);
+UFS_ATTRIBUTE_RO(psa_data_size, _PSA_DATA_SIZE);

static struct attribute *ufs_sysfs_attributes[] = {
&dev_attr_boot_lun_enabled.attr,
--
2.16.4

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