[SCSI] isci: atapi support

Based on original implementation from Jiangbi Liu and Maciej Trela.

ATAPI transfers happen in two-to-three stages.  The two stage atapi
commands are those that include a dma data transfer.  The data transfer
portion of these operations is handled by the hardware packet-dma
acceleration.  The three-stage commands do not have a data transfer and
are handled without hardware assistance in raw frame mode.

stage1: transmit host-to-device fis to notify the device of an incoming
atapi cdb.  Upon reception of the pio-setup-fis repost the task_context
to perform the dma transfer of the cdb+data (go to stage3), or repost
the task_context to transmit the cdb as a raw frame (go to stage 2).

stage2: wait for hardware notification of the cdb transmission and then
go to stage 3.

stage3: wait for the arrival of the terminating device-to-host fis and
terminate the command.

To keep the implementation simple we only support ATAPI packet-dma
protocol (for commands with data) to avoid needing to handle the data
transfer manually (like we do for SATA-PIO).  This may affect
compatibility for a small number of devices (see
ATA_HORKAGE_ATAPI_MOD16_DMA).

If the data-transfer underruns, or encounters an error the
device-to-host fis is expected to arrive in the unsolicited frame queue
to pass to libata for disposition.  However, in the DONE_UNEXP_FIS (data
underrun) case it appears we need to craft a response.  In the
DONE_REG_ERR case we do receive the UF and propagate it to libsas.

Signed-off-by: Maciej Trela <maciej.trela@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 26 insertions, 2 deletions

diff --git a/drivers/scsi/isci/request.h b/drivers/scsi/isci/request.h
index 58d70b6606ef..f720b97b7bb5 100644
--- a/drivers/scsi/isci/request.h
+++ b/drivers/scsi/isci/request.h
@@ -96,7 +96,6 @@ enum sci_request_protocol {
  *	     to wait for another fis or if the transfer is complete.  Upon
  *           receipt of a d2h fis this will be the status field of that fis.
  * @sgl - track pio transfer progress as we iterate through the sgl
- * @device_cdb_len - atapi device advertises it's transfer constraints at setup
  */
 struct isci_stp_request {
 	u32 pio_len;
@@ -107,7 +106,6 @@ struct isci_stp_request {
 		u8 set;
 		u32 offset;
 	} sgl;
-	u32 device_cdb_len;
 };
 
 struct isci_request {
@@ -249,6 +247,32 @@ enum sci_base_request_states {
 	SCI_REQ_STP_PIO_DATA_OUT,
 
 	/*
+	 * While in this state the IO request object is waiting for the TC
+	 * completion notification for the H2D Register FIS
+	 */
+	SCI_REQ_ATAPI_WAIT_H2D,
+
+	/*
+	 * While in this state the IO request object is waiting for either a
+	 * PIO Setup.
+	 */
+	SCI_REQ_ATAPI_WAIT_PIO_SETUP,
+
+	/*
+	 * The non-data IO transit to this state in this state after receiving
+	 * TC completion. While in this state IO request object is waiting for
+	 * D2H status frame as UF.
+	 */
+	SCI_REQ_ATAPI_WAIT_D2H,
+
+	/*
+	 * When transmitting raw frames hardware reports task context completion
+	 * after every frame submission, so in the non-accelerated case we need
+	 * to expect the completion for the "cdb" frame.
+	 */
+	SCI_REQ_ATAPI_WAIT_TC_COMP,
+
+	/*
 	 * The AWAIT_TC_COMPLETION sub-state indicates that the started raw
 	 * task management request is waiting for the transmission of the
 	 * initial frame (i.e. command, task, etc.).