diff mbox series

[v4,3/3] scsi: ufs: sysfs: Make max_number_of_rtt read-write

Message ID 20240516055124.24490-4-avri.altman@wdc.com
State Superseded
Headers show
Series scsi: ufs: Allow RTT negotiation | expand

Commit Message

Avri Altman May 16, 2024, 5:51 a.m. UTC 
Given the importance of the RTT parameter, we want to be able to
configure it via sysfs. This is because UFS users should be discouraged
from change UFS device parameters without the UFSHCI driver being aware
of these changes.

Signed-off-by: Avri Altman <avri.altman@wdc.com>
---
 Documentation/ABI/testing/sysfs-driver-ufs | 14 +++---
 drivers/ufs/core/ufs-sysfs.c               | 58 +++++++++++++++++++++-
 2 files changed, 65 insertions(+), 7 deletions(-)

Comments

Avri Altman May 16, 2024, 3:31 p.m. UTC | #1 
> On 5/15/24 23:51, Avri Altman wrote:
> > +static ssize_t max_number_of_rtt_store(struct device *dev,
> > +                                  struct device_attribute *attr,
> > +                                  const char *buf, size_t count)
> > +{
> > +     struct ufs_hba *hba = dev_get_drvdata(dev);
> > +     unsigned int rtt;
> > +     int ret;
> > +
> > +     if (kstrtouint(buf, 0, &rtt))
> > +             return -EINVAL;
> > +
> > +     down(&hba->host_sem);
> > +     if (!ufshcd_is_user_access_allowed(hba)) {
> > +             ret = -EBUSY;
> > +             goto out;
> > +     }
> > +
> > +     ufshcd_rpm_get_sync(hba);
> > +     ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
> > +             QUERY_ATTR_IDN_MAX_NUM_OF_RTT, 0, 0, &rtt);
> > +     ufshcd_rpm_put_sync(hba);
> > +
> > +out:
> > +     up(&hba->host_sem);
> > +     return ret < 0 ? ret : count;
> > +}
> 
> Since modifying RTT is only allowed while no commands are in progress,
> shouldn't max_number_of_rtt_store() freeze and unfreeze all request
> queues of all logical units?
Done.

Thanks,
Avri

> 
> Thanks,
> 
> Bart.
diff mbox series

Patch

diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs
index 5bf7073b4f75..fe943ce76c60 100644
--- a/Documentation/ABI/testing/sysfs-driver-ufs
+++ b/Documentation/ABI/testing/sysfs-driver-ufs
@@ -920,14 +920,16 @@  Description:	This file shows whether the configuration descriptor is locked.
 
 What:		/sys/bus/platform/drivers/ufshcd/*/attributes/max_number_of_rtt
 What:		/sys/bus/platform/devices/*.ufs/attributes/max_number_of_rtt
-Date:		February 2018
-Contact:	Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
+Date:		May 2024
+Contact:	Avri Altman <avri.altman@wdc.com>
 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.
+		outstanding RTTs in device that is allowed. bMaxNumOfRTT is a
+		read-write persistent attribute and is equal to two after device
+		manufacturing. It shall not be set to a value greater than
+		bDeviceRTTCap value, and it may be set only when the hw queues are
+		empty.
 
-		The file is read only.
+		The file is read write.
 
 What:		/sys/bus/platform/drivers/ufshcd/*/attributes/exception_event_control
 What:		/sys/bus/platform/devices/*.ufs/attributes/exception_event_control
diff --git a/drivers/ufs/core/ufs-sysfs.c b/drivers/ufs/core/ufs-sysfs.c
index 3d049967f6bc..8c6aeb836407 100644
--- a/drivers/ufs/core/ufs-sysfs.c
+++ b/drivers/ufs/core/ufs-sysfs.c
@@ -1340,6 +1340,63 @@  static const struct attribute_group ufs_sysfs_flags_group = {
 	.attrs = ufs_sysfs_device_flags,
 };
 
+static ssize_t max_number_of_rtt_show(struct device *dev,
+				      struct device_attribute *attr, char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+	u32 rtt;
+	int ret;
+
+	down(&hba->host_sem);
+	if (!ufshcd_is_user_access_allowed(hba)) {
+		up(&hba->host_sem);
+		return -EBUSY;
+	}
+
+	ufshcd_rpm_get_sync(hba);
+	ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,
+		QUERY_ATTR_IDN_MAX_NUM_OF_RTT, 0, 0, &rtt);
+	ufshcd_rpm_put_sync(hba);
+
+	if (ret)
+		goto out;
+
+	ret = sysfs_emit(buf, "0x%08X\n", rtt);
+
+out:
+	up(&hba->host_sem);
+	return ret;
+}
+
+static ssize_t max_number_of_rtt_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+	unsigned int rtt;
+	int ret;
+
+	if (kstrtouint(buf, 0, &rtt))
+		return -EINVAL;
+
+	down(&hba->host_sem);
+	if (!ufshcd_is_user_access_allowed(hba)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	ufshcd_rpm_get_sync(hba);
+	ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
+		QUERY_ATTR_IDN_MAX_NUM_OF_RTT, 0, 0, &rtt);
+	ufshcd_rpm_put_sync(hba);
+
+out:
+	up(&hba->host_sem);
+	return ret < 0 ? ret : count;
+}
+
+static DEVICE_ATTR_RW(max_number_of_rtt);
+
 static inline bool ufshcd_is_wb_attrs(enum attr_idn idn)
 {
 	return idn >= QUERY_ATTR_IDN_WB_FLUSH_STATUS &&
@@ -1387,7 +1444,6 @@  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);