USB: mass storage: emulation of sat scsi_pass_thru with ATACB

I have got a cypress usb-ide bridge and I would like to tune or monitor
my disk with tools like hdparm, hddtemp or smartctl.

My controller support a way to send raw ATA command to the disk with
something call atacb (see
http://download.cypress.com.edgesuite.net/design_resources/datasheets/contents/cy7c68300c_8.pdf).

Atacb support can be added for each application, but there is some disadvantages :
- all application need to be patched
- A race is possible if there other accesses, because the emulation can
be split in 2 atacb scsi transactions. One for sending the command, one
for reading the register (if ck_cond is set). 

I have implemented the emulation in usb-storage with a special proto_handler,
and an unsual entry.

Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
index bdd4334bed5a7..4628f03b13bff 100644
--- a/drivers/usb/storage/transport.c
+++ b/drivers/usb/storage/transport.c
@@ -603,7 +603,8 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
 		scsi_eh_prep_cmnd(srb, &ses, NULL, 0, US_SENSE_SIZE);
 
 		/* FIXME: we must do the protocol translation here */
-		if (us->subclass == US_SC_RBC || us->subclass == US_SC_SCSI)
+		if (us->subclass == US_SC_RBC || us->subclass == US_SC_SCSI ||
+				us->subclass == US_SC_CYP_ATACB)
 			srb->cmd_len = 6;
 		else
 			srb->cmd_len = 12;