This change enables Linux to enumerate UFS devices that have been configured to start in an initial power mode (bInitPowerMode) of sleep. The UFS spec indicates that for devices in sleep mode, a START_STOP_UNIT SCSI command must be sent to them to wake them up before doing other initialization tasks like getting the device or geometry descriptors. This is not trivial to do in the UFS driver, since it assumes that SCSI commands are only needed once low level initialization of the device is complete. These patches 1) Enable sending SCSI commands before the actual SCSI targets are created, and 2) Sends the needed commands for devices in sleep mode. This can be tested locally by setting byte 5 of the Configuration Descriptor (bInitPowerMode) to zero, and rebooting. I discovered this bug by accidentally zeroing out too many fields while I was testing provisioning functionality. Note: This series is unrelated to (and independent of) the competing UFS provisioning patches that have been floating around the list lately. Changes since v1: * Split into two patches for easier comprehension. Can recombine to one if this split is too contrived. * Fixed a leftover raw printk. Evan Green (2): scsi: ufs: Allow SCSI commands early during init scsi: ufs: Execute START_STOP_UNIT during init drivers/scsi/ufs/ufshcd.c | 208 +++++++++++++++++++++++++++++++++++++++++++--- drivers/scsi/ufs/ufshcd.h | 11 +++ 2 files changed, 206 insertions(+), 13 deletions(-) -- 2.16.4
