Hi Sayali, On Mon, Jul 16, 2018 at 1:10 AM Sayali Lokhande <sayalil@xxxxxxxxxxxxxx> wrote: > > Hi Evan, > > > On 7/9/2018 11:18 PM, Evan Green wrote: > > Hi Sayali, > > Thanks for the prompt spin. > > > > On Thu, Jul 5, 2018 at 11:21 PM Sayali Lokhande <sayalil@xxxxxxxxxxxxxx> wrote: > >> This patch adds configfs support to provision ufs device at > > s/ufs/UFS/ > Will update. > >> runtime. This feature can be primarily useful in factory or > >> assembly line as some devices may be required to be configured > >> multiple times during initial system development phase. > >> Configuration Descriptors can be written multiple times until > >> bConfigDescrLock attribute is zero. > >> > >> Configuration descriptor buffer consists of Device and Unit > >> descriptor configurable parameters which are parsed from vendor > >> specific provisioning file and then passed via configfs node at > >> runtime to provision ufs device. > >> CONFIG_CONFIGFS_FS needs to be enabled for using this feature. > >> > >> Usage: > >> 1) To read current configuration descriptor : > >> cat /config/ufshcd/ufs_provision > >> 2) To provision ufs device: > >> echo <config_desc_buf> > /config/ufshcd/ufs_provision > >> > >> Signed-off-by: Sayali Lokhande <sayalil@xxxxxxxxxxxxxx> > >> --- > >> Documentation/ABI/testing/configfs-driver-ufs | 18 +++ > >> drivers/scsi/ufs/Makefile | 1 + > >> drivers/scsi/ufs/ufs-configfs.c | 172 ++++++++++++++++++++++++++ > >> drivers/scsi/ufs/ufshcd.c | 2 + > >> drivers/scsi/ufs/ufshcd.h | 19 +++ > >> 5 files changed, 212 insertions(+) > >> create mode 100644 Documentation/ABI/testing/configfs-driver-ufs > >> create mode 100644 drivers/scsi/ufs/ufs-configfs.c > >> > >> diff --git a/Documentation/ABI/testing/configfs-driver-ufs b/Documentation/ABI/testing/configfs-driver-ufs > >> new file mode 100644 > >> index 0000000..dd16842 > >> --- /dev/null > >> +++ b/Documentation/ABI/testing/configfs-driver-ufs > >> @@ -0,0 +1,18 @@ > >> +What: /config/ufshcd/ufs_provision > >> +Date: Jun 2018 > >> +KernelVersion: 4.14 > >> +Description: > >> + This file shows the current ufs configuration descriptor set in device. > >> + This can be used to provision ufs device if bConfigDescrLock is 0. > >> + For more details, refer 14.1.6.3 Configuration Descriptor and > >> + Table 14-12 — Unit Descriptor configurable parameters from specs for > > Can this be a regular dash, rather than some sort of exotic 0xE2 byte. > > > >> + description of each configuration descriptor parameter. > >> + Configuration descriptor buffer needs to be passed in space separated > >> + format specificied as below: > >> + echo <bLength> <bDescriptorIDN> <bConfDescContinue> <bBootEnable> > >> + <bDescrAccessEn> <bInitPowerMode> <bHighPriorityLUN> > >> + <bSecureRemovalType> <bInitActiveICCLevel> <wPeriodicRTCUpdate> > >> + <0Bh:0Fh_ReservedAs_0> <bLUEnable> <bBootLunID> <bLUWriteProtect> > >> + <bMemoryType> <dNumAllocUnits> <bDataReliability> <bLogicalBlockSize> > >> + <bProvisioningType> <wContextCapabilities> <0Dh:0Fh_ReservedAs_0> > > I wonder if at this point we should be using a binary attribute rather > > than a text one. Since now you're basically just converting text to > > bytes, it's not very human anymore. > Use of binary attr was ruled out before. Pasting previous comments from > Greg : > "binary attributes are meant for hardware value pass-through" type stuff. > Unless this is "raw" data straight from the hardware, binary does not work. But now that we've removed the software parameters like lun_to_grow, and all the calculations, this is exactly a hardware value pass-through, isn't it? I even see you have things like <0Bh:0Fh_ReservedAs_0> done in order to match the hardware format. I see Bart has chimed in on the next series with a suggestion to break out each field into individual files within configfs. Bart, what are your feelings about converting to a binary attribute? I remember when I did my sysfs equivalent of this patch, somebody chimed in indicating a "commit" file might be needed so that the new configuration could be written in one fell swoop. One advantage of the binary attribute is that it writes the configuration atomically. -Evan
