On Thu, 2013-05-02 at 17:25 +0530, Santosh Y wrote: > From: Dolev Raviv <draviv@xxxxxxxxxxxxxx> > > Add support for sending UFS query requests through tagged command > queuing. This design allows queuing query requests in any open slot > along with other SCSI commands. In this way there is no need to > save a slot in the requests queue and decrease its size. > > A query request is posing to a SCSI command to use native flow. But > unlike normal SCSI command flow, the data and response fields are > filled in UFS host data structure instead of passing as arguments > while queuing into SCSI mlqueue (mid-layer SCSI queue, the requests > from this queue are submitted to the device queue). As per specification > only one query request is allowed to be processed by device. Hence a > mutex lock for protecting data and response fields (hba->query.request and > hba->query.response) needs to be held while query request is in > progress. > > The API for submitting a query request is ufs_query_request() in > ufshcd.c. This function is responsible for: > 1. Obtaining the SCSI device from the host > 2. Keeping the query mutex to prevent multiple queries > 3. Storing the required data for sending a query request in ufs_hba > 4. Queuing a SCSI vendor specific command to trigger a query request > in the UFS driver. > > The callers of ufs_query_request() are expected to fill the query > command data fields and are to provide an allocated response field > for the driver to fill response fields after request completion. > > The request and response upiu is extended in a union to enable using the > same data structure, both for command upiu and query request upiu. > > The query request flow is separated from the scsi command flow in: > 1. Preparing the request > 2. Validating response (error) codes > 3. Copying data (only used for descriptor read/write query requests) > 4. Copying response/sense > > Data error can't be handled in the scsi command native flow. Hence, > we pass the code as without a change back to the submitting layer. > > UPIU (UFS Protocol Information Unit) size is increased to 512 bytes > from 128. The UPIU header and the transaction specific fields (SCSI > command or Query Request OSF - Op-code Specific Fields) are 32 bytes > together, the rest is used to transfer extra request data (such as > descriptor in query requests). In order to accommodate the largest > descriptor in the UFS spec (256 bytes) we need to increase the UPIU > size. > > Signed-off-by: Dolev Raviv <draviv@xxxxxxxxxxxxxx> > Signed-off-by: Santosh Y <santoshsy@xxxxxxxxx> > > diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig > index 35faf24..82417d6 100644 > --- a/drivers/scsi/ufs/Kconfig > +++ b/drivers/scsi/ufs/Kconfig > @@ -35,6 +35,7 @@ > config SCSI_UFSHCD > tristate "Universal Flash Storage Controller Driver Core" > depends on SCSI > + default y > ---help--- > This selects the support for UFS devices in Linux, say Y and make > sure that you know the name of your UFS host adapter (the card I don't think you want to force this on in every configuration since it's only appropriate to non server/desktop. I stripped this hunk. James -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
