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Diffstat (limited to 'Documentation/scsi')
| -rw-r--r-- | Documentation/scsi/ufs.txt | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/scsi/ufs.txt b/Documentation/scsi/ufs.txt index 41a6164592aa..520b5b033256 100644 --- a/Documentation/scsi/ufs.txt +++ b/Documentation/scsi/ufs.txt @@ -128,6 +128,26 @@ The current UFSHCD implementation supports following functionality, In this version of UFSHCD Query requests and power management functionality are not implemented. +4. BSG Support +------------------ + +This transport driver supports exchanging UFS protocol information units +(UPIUs) with a UFS device. Typically, user space will allocate +struct ufs_bsg_request and struct ufs_bsg_reply (see ufs_bsg.h) as +request_upiu and reply_upiu respectively. Filling those UPIUs should +be done in accordance with JEDEC spec UFS2.1 paragraph 10.7. +*Caveat emptor*: The driver makes no further input validations and sends the +UPIU to the device as it is. Open the bsg device in /dev/ufs-bsg and +send SG_IO with the applicable sg_io_v4: + + io_hdr_v4.guard = 'Q'; + io_hdr_v4.protocol = BSG_PROTOCOL_SCSI; + io_hdr_v4.subprotocol = BSG_SUB_PROTOCOL_SCSI_TRANSPORT; + io_hdr_v4.response = (__u64)reply_upiu; + io_hdr_v4.max_response_len = reply_len; + io_hdr_v4.request_len = request_len; + io_hdr_v4.request = (__u64)request_upiu; + UFS Specifications can be found at, UFS - http://www.jedec.org/sites/default/files/docs/JESD220.pdf UFSHCI - http://www.jedec.org/sites/default/files/docs/JESD223.pdf |