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>

Add Real Time Clock (RTC) support for UFS device. This enhancement is
crucial for the internal maintenance operations of the UFS device. The
patch enables the device to handle both absolute and relative time
information. Furthermore, it includes periodic task to update the RTC in
accordance with the UFS Spec, ensuring the accuracy of RTC information for
the device's internal processes.

RTC and qTimestamp serve distinct purposes. The RTC provides a coarse level
of granularity with, at best, approximate single-second resolution. This
makes the RTC well-suited for the device to determine the approximate age
of programmed blocks after being updated by the host. On the other hand,
qTimestamp offers nanosecond granularity and is specifically designed for
synchronizing Device Error Log entries with corresponding host-side logs.

Given that the RTC has been a standard feature since UFS Spec 2.0, and
qTimestamp was introduced in UFS Spec 4.0, the majority of UFS devices
currently on the market rely on RTC. Therefore, it is advisable to continue
supporting RTC in the Linux kernel. This ensures compatibility with the
prevailing UFS device implementations and facilitates seamless integration
with existing hardware.  By maintaining support for RTC, we ensure broad
compatibility and avoid potential issues arising from deviations in device
specifications across different UFS versions.

Signed-off-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Mike Bi <mikebi@micron.com>
Signed-off-by: Luca Porzio <lporzio@micron.com>
Link: https://lore.kernel.org/r/20231212220825.85255-3-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>

Make the UFS device execute realtime (RT) requests before other requests.
This will be used in Android to reduce the I/O latency of the foreground
app.

Note: UFS devices do not support CDL so using CDL is not a viable
alternative.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230921192335.676924-5-bvanassche@acm.org
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Make the code that parses UTP transfer request headers easier to read by
using u8 instead of __be32 where appropriate.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230727194457.3152309-13-bvanassche@acm.org
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Make the code that initializes UTP transfer request headers easier to read
by using bitfields instead of __le32 where appropriate.

Cc: "Bao D. Nguyen" <quic_nguyenb@quicinc.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Avri Altman <avri.altman@wdc.com>
Cc: Bean Huo <beanhuo@micron.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230727194457.3152309-12-bvanassche@acm.org
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Remove the 'response' member variable because no code reads its value.
Additionally, move the ufs_query_req and ufs_query_res data structure
definitions into include/ufs/ufshcd.h because these data structures are
related to the UFS host controller driver.

Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230727194457.3152309-11-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Assign names to the enumeration types for UPIU types. Use these enumeration
types where appropriate.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230727194457.3152309-8-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Only #include those header files that are needed.

Note: include/ufs/ufshcd.h needs <scsi/scsi_host.h> because of SG_ALL.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230727194457.3152309-6-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Only call scsi_set_resid() in case of an underflow. Do not call
scsi_set_resid() in case of an overflow.

Cc: Avri Altman <avri.altman@wdc.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Fixes: cb38845d90fc ("scsi: ufs: core: Set the residual byte count")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230724200843.3376570-2-bvanassche@acm.org
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>