scsi: ufs: core: Add sysfs node for UFS RTC update

Introduce a sysfs node named 'rtc_update_ms' within the kernel, enabling
user to adjust the RTC periodic update frequency to suit the specific
requirements of the system and UFS. Also, this patch allows the user to
disable/enable periodic update RTC in the UFS idle time.

Signed-off-by: Bean Huo <beanhuo@micron.com>
Link: https://lore.kernel.org/r/20231212220825.85255-4-beanhuo@iokpp.de
Acked-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs
index 0c7efaf62de0c00b5f481b27e547fd24a022959f..ef1e27584fff303e0f05b9440155e36fa68ecf1c 100644 (file)
--- a/Documentation/ABI/testing/sysfs-driver-ufs
+++ b/Documentation/ABI/testing/sysfs-driver-ufs
@@ -1474,3 +1474,10 @@ Description:     Indicates status of Write Booster.
 
                The file is read only.
 
+What:          /sys/bus/platform/drivers/ufshcd/*/rtc_update_ms
+What:          /sys/bus/platform/devices/*.ufs/rtc_update_ms
+Date:          November 2023
+Contact:       Bean Huo <beanhuo@micron.com>
+Description:
+               rtc_update_ms indicates how often the host should synchronize or update the
+               UFS RTC. If set to 0, this will disable UFS RTC periodic update.

diff --git a/drivers/ufs/core/ufs-sysfs.c b/drivers/ufs/core/ufs-sysfs.c
index c95906443d5f9d5548ec6c03ec5b051fbbf6531e..4ead1e3bdb12cb27902ec4aae298342562af1d7d 100644 (file)
--- a/drivers/ufs/core/ufs-sysfs.c
+++ b/drivers/ufs/core/ufs-sysfs.c
@@ -255,6 +255,35 @@ out:
        return res < 0 ? res : count;
 }
 
+static ssize_t rtc_update_ms_show(struct device *dev, struct device_attribute *attr,
+                                 char *buf)
+{
+       struct ufs_hba *hba = dev_get_drvdata(dev);
+
+       return sysfs_emit(buf, "%d\n", hba->dev_info.rtc_update_period);
+}
+
+static ssize_t rtc_update_ms_store(struct device *dev, struct device_attribute *attr,
+                                  const char *buf, size_t count)
+{
+       struct ufs_hba *hba = dev_get_drvdata(dev);
+       unsigned int ms;
+       bool resume_period_update = false;
+
+       if (kstrtouint(buf, 0, &ms))
+               return -EINVAL;
+
+       if (!hba->dev_info.rtc_update_period && ms > 0)
+               resume_period_update =  true;
+       /* Minimum and maximum update frequency should be synchronized with all UFS vendors */
+       hba->dev_info.rtc_update_period = ms;
+
+       if (resume_period_update)
+               schedule_delayed_work(&hba->ufs_rtc_update_work,
+                                     msecs_to_jiffies(hba->dev_info.rtc_update_period));
+       return count;
+}
+
 static ssize_t enable_wb_buf_flush_show(struct device *dev,
                                    struct device_attribute *attr,
                                    char *buf)
@@ -339,6 +368,7 @@ static DEVICE_ATTR_RW(auto_hibern8);
 static DEVICE_ATTR_RW(wb_on);
 static DEVICE_ATTR_RW(enable_wb_buf_flush);
 static DEVICE_ATTR_RW(wb_flush_threshold);
+static DEVICE_ATTR_RW(rtc_update_ms);
 
 static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
        &dev_attr_rpm_lvl.attr,
@@ -351,6 +381,7 @@ static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
        &dev_attr_wb_on.attr,
        &dev_attr_enable_wb_buf_flush.attr,
        &dev_attr_wb_flush_threshold.attr,
+       &dev_attr_rtc_update_ms.attr,
        NULL
 };
 

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 99ad9b76904897e01caad0369475c83917429055..5c4ef4b072c387738ec4a8bbe3822e323a6050ab 100644 (file)
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -8233,9 +8233,9 @@ static void ufshcd_rtc_work(struct work_struct *work)
        if (!ufshcd_is_ufs_dev_busy(hba) && hba->ufshcd_state == UFSHCD_STATE_OPERATIONAL)
                ufshcd_update_rtc(hba);
 
-       if (ufshcd_is_ufs_dev_active(hba))
+       if (ufshcd_is_ufs_dev_active(hba) && hba->dev_info.rtc_update_period)
                schedule_delayed_work(&hba->ufs_rtc_update_work,
-                                     msecs_to_jiffies(UFS_RTC_UPDATE_INTERVAL_MS));
+                                     msecs_to_jiffies(hba->dev_info.rtc_update_period));
 }
 
 static void ufs_init_rtc(struct ufs_hba *hba, u8 *desc_buf)
@@ -8257,6 +8257,13 @@ static void ufs_init_rtc(struct ufs_hba *hba, u8 *desc_buf)
                dev_info->rtc_type = UFS_RTC_RELATIVE;
                dev_info->rtc_time_baseline = 0;
        }
+
+       /*
+        * We ignore TIME_PERIOD defined in wPeriodicRTCUpdate because Spec does not clearly state
+        * how to calculate the specific update period for each time unit. And we disable periodic
+        * RTC update work, let user configure by sysfs node according to specific circumstance.
+        */
+       dev_info->rtc_update_period = 0;
 }
 
 static int ufs_get_device_desc(struct ufs_hba *hba)

diff --git a/include/ufs/ufs.h b/include/ufs/ufs.h
index 7e7169d94596390c8d627adc57b3780f56f17029..b6003749bc83a2cf582df7681052f0bdd630efc0 100644 (file)
--- a/include/ufs/ufs.h
+++ b/include/ufs/ufs.h
@@ -591,6 +591,7 @@ struct ufs_dev_info {
        /* UFS RTC */
        enum ufs_rtc_time rtc_type;
        time64_t rtc_time_baseline;
+       u32 rtc_update_period;
 };
 
 /*