Re: [PATCH] mass storage : emulation of sat scsi_pass_thru withATACB

From: matthieu castet
Date: Wed Mar 19 2008 - 16:22:06 EST

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Matthew Dharm wrote:

Matt --

I just noticed that it's been about a week since I sent this...

Any progress?

Sorry I was a bit busy.

Matt

On Thu, Mar 13, 2008 at 05:51:39PM -0700, Matthew Dharm wrote:
On Thu, Mar 13, 2008 at 10:22:09PM +0100, matthieu castet wrote:
Matthew Dharm wrote:
On Sun, Mar 09, 2008 at 10:42:50PM +0100, matthieu castet wrote:
Hi

here an update version of the patch
We're getting very close here.
+ unsigned char sk, asc, ascq;
+ sk = RECOVERED_ERROR;
+ asc = 0; /* ATA PASS THROUGH INFORMATION AVAILABLE */
+ ascq = 0x1D;
+ /* XXX we should generate sk, asc, ascq from status and error
+ * regs
+ * (see 11.1 Error translation ? ATA device error to SCSI error map)
+ * and ata_to_sense_error from libata.
+ */
+ sb[1] = sk;
+ sb[2] = asc;
+ sb[3] = ascq;

I may have missed this in an earlier patch, but why to you declare and use
these 3 variables like this? Seems odd and confusing to me....

I did that because in previous patch I was saving value from the first sense buffer if the first atacb command failed.
But after some test, I saw the returned values were always 0 and I always set the same value.
I think I can remove them now.

Patch with sk, asc, ascq removed attached.

Matthieu

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@xxxxxxx>

Index: linux-2.6/drivers/usb/storage/unusual_devs.h
===================================================================
--- linux-2.6.orig/drivers/usb/storage/unusual_devs.h 2008-02-28 11:21:20.000000000 +0100
+++ linux-2.6/drivers/usb/storage/unusual_devs.h 2008-03-13 21:19:21.000000000 +0100
@@ -1620,6 +1620,14 @@
US_SC_DEVICE, US_PR_DEVICE, NULL,
US_FL_CAPACITY_HEURISTICS),

+#ifdef CONFIG_USB_STORAGE_CYPRESS_ATACB
+UNUSUAL_DEV( 0x04b4, 0x6830, 0x0000, 0x9999,
+ "Cypress",
+ "Cypress AT2LP",
+ US_SC_CYP_ATACB, US_PR_BULK, NULL,
+ 0),
+#endif
+
/* Control/Bulk transport for all SubClass values */
USUAL_DEV(US_SC_RBC, US_PR_CB, USB_US_TYPE_STOR),
USUAL_DEV(US_SC_8020, US_PR_CB, USB_US_TYPE_STOR),
Index: linux-2.6/drivers/usb/storage/cypress_atacb.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6/drivers/usb/storage/cypress_atacb.c 2008-03-19 19:34:11.000000000 +0100
@@ -0,0 +1,200 @@
+/*
+ * Support for emulating SAT (ata pass through) on devices based
+ * on the Cypress USB/ATA bridge supporting ATACB.
+ *
+ * Copyright (c) 2008 Matthieu Castet (castet.matthieu@xxxxxxx)
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_eh.h>
+#include <linux/ata.h>
+
+#include "usb.h"
+#include "protocol.h"
+#include "scsiglue.h"
+#include "debug.h"
+
+/*
+ * ATACB is a protocol used on cypress usb<->ata bridge to
+ * send raw ATA command over mass storage
+ * There is a ATACB2 protocol that support LBA48 on newer chip.
+ * More info that be found on cy7c68310_8.pdf and cy7c68300c_8.pdf
+ * datasheet from cypress.com.
+ */
+void cypress_atacb_passthrough(struct scsi_cmnd *srb, struct us_data *us)
+{
+ unsigned char save_cmnd[MAX_COMMAND_SIZE];
+
+ if (likely(srb->cmnd[0] != ATA_16 && srb->cmnd[0] != ATA_12)) {
+ usb_stor_transparent_scsi_command(srb, us);
+ return;
+ }
+
+ memcpy(save_cmnd, srb->cmnd, sizeof(save_cmnd));
+ memset(srb->cmnd, 0, sizeof(srb->cmnd));
+
+ /* check if we support the command */
+ if (save_cmnd[1] >> 5) /* MULTIPLE_COUNT */
+ goto invalid_fld;
+ /* check protocol */
+ switch((save_cmnd[1] >> 1) & 0xf) {
+ case 3: /*no DATA */
+ case 4: /* PIO in */
+ case 5: /* PIO out */
+ break;
+ default:
+ goto invalid_fld;
+ }
+
+ /* first build the ATACB command */
+ srb->cmd_len = 16;
+
+ srb->cmnd[0] = 0x24; /* bVSCBSignature : vendor-specific command
+ this value can change, but most(all ?) manufacturers
+ keep the cypress default : 0x24 */
+ srb->cmnd[1] = 0x24; /* bVSCBSubCommand : 0x24 for ATACB */
+
+ srb->cmnd[3] = 0xff - 1; /* features, sector count, lba low, lba med
+ lba high, device, command are valid */
+ srb->cmnd[4] = 1; /* TransferBlockCount : 512 */
+
+ if (save_cmnd[0] == ATA_16) {
+ srb->cmnd[ 6] = save_cmnd[ 4]; /* features */
+ srb->cmnd[ 7] = save_cmnd[ 6]; /* sector count */
+ srb->cmnd[ 8] = save_cmnd[ 8]; /* lba low */
+ srb->cmnd[ 9] = save_cmnd[10]; /* lba med */
+ srb->cmnd[10] = save_cmnd[12]; /* lba high */
+ srb->cmnd[11] = save_cmnd[13]; /* device */
+ srb->cmnd[12] = save_cmnd[14]; /* command */
+
+ if (save_cmnd[1] & 0x01) {/* extended bit set for LBA48 */
+ /* this could be supported by atacb2 */
+ if (save_cmnd[3] || save_cmnd[5] || save_cmnd[7] || save_cmnd[9]
+ || save_cmnd[11])
+ goto invalid_fld;
+ }
+ }
+ else { /* ATA12 */
+ srb->cmnd[ 6] = save_cmnd[3]; /* features */
+ srb->cmnd[ 7] = save_cmnd[4]; /* sector count */
+ srb->cmnd[ 8] = save_cmnd[5]; /* lba low */
+ srb->cmnd[ 9] = save_cmnd[6]; /* lba med */
+ srb->cmnd[10] = save_cmnd[7]; /* lba high */
+ srb->cmnd[11] = save_cmnd[8]; /* device */
+ srb->cmnd[12] = save_cmnd[9]; /* command */
+
+ }
+ /* Filter SET_FEATURES - XFER MODE command */
+ if ((srb->cmnd[12] == ATA_CMD_SET_FEATURES)
+ && (srb->cmnd[6] == SETFEATURES_XFER))
+ goto invalid_fld;
+
+ if (srb->cmnd[12] == ATA_CMD_ID_ATA || srb->cmnd[12] == ATA_CMD_ID_ATAPI)
+ srb->cmnd[2] |= (1<<7); /* set IdentifyPacketDevice for these cmds */
+
+
+ usb_stor_transparent_scsi_command(srb, us);
+
+ /* if the device doesn't support ATACB
+ */
+ if (srb->result == SAM_STAT_CHECK_CONDITION &&
+ memcmp(srb->sense_buffer, usb_stor_sense_invalidCDB,
+ sizeof(usb_stor_sense_invalidCDB)) == 0) {
+ US_DEBUGP("cypress atacb not supported ???\n");
+ goto end;
+ }
+
+ /* if ck_cond flags is set, and there wasn't critical error,
+ * build the special sense
+ */
+ if ((srb->result != (DID_ERROR << 16) &&
+ srb->result != (DID_ABORT << 16)) &&
+ save_cmnd[2] & 0x20) {
+ struct scsi_eh_save ses;
+ unsigned char regs[8];
+ unsigned char *sb = srb->sense_buffer;
+ unsigned char *desc = sb + 8;
+ int tmp_result;
+
+ /* build the command for
+ * reading the ATA registers */
+ scsi_eh_prep_cmnd(srb, &ses, NULL, 0, 0);
+ srb->sdb.length = sizeof(regs);
+ sg_init_one(&ses.sense_sgl, regs, srb->sdb.length);
+ srb->sdb.table.sgl = &ses.sense_sgl;
+ srb->sc_data_direction = DMA_FROM_DEVICE;
+ srb->sdb.table.nents = 1;
+ /* we use the same command as before, but we set
+ * the read taskfile bit, for not executing atacb command,
+ * but reading register selected in srb->cmnd[4]
+ */
+ srb->cmnd[2] = 1;
+
+ usb_stor_transparent_scsi_command(srb, us);
+ tmp_result = srb->result;
+ scsi_eh_restore_cmnd(srb, &ses);
+ /* we fail to get registers, report invalid command */
+ if (tmp_result != SAM_STAT_GOOD)
+ goto invalid_fld;
+
+ /* build the sense */
+ memset(sb, 0, SCSI_SENSE_BUFFERSIZE);
+
+ /* set sk, asc for a good command */
+ sb[1] = RECOVERED_ERROR;
+ sb[2] = 0; /* ATA PASS THROUGH INFORMATION AVAILABLE */
+ sb[3] = 0x1D;
+
+ /* XXX we should generate sk, asc, ascq from status and error
+ * regs
+ * (see 11.1 Error translation ATA device error to SCSI error map)
+ * and ata_to_sense_error from libata.
+ */
+
+ /* Sense data is current and format is descriptor. */
+ sb[0] = 0x72;
+ desc[0] = 0x09; /* ATA_RETURN_DESCRIPTOR */
+
+ /* set length of additional sense data */
+ sb[7] = 14;
+ desc[1] = 12;
+
+ /* Copy registers into sense buffer. */
+ desc[ 2] = 0x00;
+ desc[ 3] = regs[1]; /* features */
+ desc[ 5] = regs[2]; /* sector count */
+ desc[ 7] = regs[3]; /* lba low */
+ desc[ 9] = regs[4]; /* lba med */
+ desc[11] = regs[5]; /* lba high */
+ desc[12] = regs[6]; /* device */
+ desc[13] = regs[7]; /* command */
+
+ srb->result = (DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;
+ }
+ goto end;
+invalid_fld:
+ srb->result = (DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;
+
+ memcpy(srb->sense_buffer,
+ usb_stor_sense_invalidCDB,
+ sizeof(usb_stor_sense_invalidCDB));
+end:
+ memcpy(srb->cmnd, save_cmnd, sizeof(save_cmnd));
+ if (srb->cmnd[0] == ATA_12)
+ srb->cmd_len = 12;
+}
Index: linux-2.6/drivers/usb/storage/cypress_atacb.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6/drivers/usb/storage/cypress_atacb.h 2008-03-13 21:19:21.000000000 +0100
@@ -0,0 +1,25 @@
+/*
+ * Support for emulating SAT (ata pass through) on devices based
+ * on the Cypress USB/ATA bridge supporting ATACB.
+ *
+ * Copyright (c) 2008 Matthieu Castet (castet.matthieu@xxxxxxx)
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef _CYPRESS_ATACB_H_
+#define _CYPRESS_ATACB_H_
+extern void cypress_atacb_passthrough(struct scsi_cmnd*, struct us_data*);
+#endif
Index: linux-2.6/drivers/usb/storage/Kconfig
===================================================================
--- linux-2.6.orig/drivers/usb/storage/Kconfig 2007-11-29 11:03:48.000000000 +0100
+++ linux-2.6/drivers/usb/storage/Kconfig 2008-03-13 21:19:21.000000000 +0100
@@ -145,6 +145,17 @@
on the resulting scsi device node returns the Karma to normal
operation.

+config USB_STORAGE_CYPRESS_ATACB
+ bool "SAT emulation on Cypress USB/ATA Bridge with ATACB"
+ depends on USB_STORAGE
+ ---help---
+ Say Y here if you want to use SAT (ata pass through) on devices based
+ on the Cypress USB/ATA bridge supporting ATACB. This will allow you
+ to use tools to tune and monitor your drive (like hdparm or smartctl).
+
+ If you say no here your device will still work with the standard usb
+ mass storage class.
+
config USB_LIBUSUAL
bool "The shared table of common (or usual) storage devices"
depends on USB
Index: linux-2.6/drivers/usb/storage/Makefile
===================================================================
--- linux-2.6.orig/drivers/usb/storage/Makefile 2007-06-08 14:22:39.000000000 +0200
+++ linux-2.6/drivers/usb/storage/Makefile 2008-03-13 21:19:21.000000000 +0100
@@ -21,6 +21,7 @@
usb-storage-obj-$(CONFIG_USB_STORAGE_ALAUDA) += alauda.o
usb-storage-obj-$(CONFIG_USB_STORAGE_ONETOUCH) += onetouch.o
usb-storage-obj-$(CONFIG_USB_STORAGE_KARMA) += karma.o
+usb-storage-obj-$(CONFIG_USB_STORAGE_CYPRESS_ATACB) += cypress_atacb.o

usb-storage-objs := scsiglue.o protocol.o transport.o usb.o \
initializers.o $(usb-storage-obj-y)
Index: linux-2.6/drivers/usb/storage/scsiglue.c
===================================================================
--- linux-2.6.orig/drivers/usb/storage/scsiglue.c 2008-02-05 09:42:21.000000000 +0100
+++ linux-2.6/drivers/usb/storage/scsiglue.c 2008-03-13 21:19:21.000000000 +0100
@@ -132,7 +132,7 @@
/* Disk-type devices use MODE SENSE(6) if the protocol
* (SubClass) is Transparent SCSI, otherwise they use
* MODE SENSE(10). */
- if (us->subclass != US_SC_SCSI)
+ if (us->subclass != US_SC_SCSI && us->subclass != US_SC_CYP_ATACB)
sdev->use_10_for_ms = 1;

/* Many disks only accept MODE SENSE transfer lengths of
Index: linux-2.6/drivers/usb/storage/transport.c
===================================================================
--- linux-2.6.orig/drivers/usb/storage/transport.c 2008-02-28 11:21:20.000000000 +0100
+++ linux-2.6/drivers/usb/storage/transport.c 2008-03-13 21:19:21.000000000 +0100
@@ -603,7 +603,8 @@
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;
Index: linux-2.6/drivers/usb/storage/usb.c
===================================================================
--- linux-2.6.orig/drivers/usb/storage/usb.c 2007-11-29 11:03:48.000000000 +0100
+++ linux-2.6/drivers/usb/storage/usb.c 2008-03-13 21:19:21.000000000 +0100
@@ -101,6 +101,9 @@
#ifdef CONFIG_USB_STORAGE_KARMA
#include "karma.h"
#endif
+#ifdef CONFIG_USB_STORAGE_CYPRESS_ATACB
+#include "cypress_atacb.h"
+#endif

/* Some informational data */
MODULE_AUTHOR("Matthew Dharm <mdharm-usb@xxxxxxxxxxxxxxxxxx>");
@@ -708,6 +711,13 @@
break;
#endif

+#ifdef CONFIG_USB_STORAGE_CYPRESS_ATACB
+ case US_SC_CYP_ATACB:
+ us->protocol_name = "Transparent SCSI with Cypress ATACB";
+ us->proto_handler = cypress_atacb_passthrough;
+ break;
+#endif
+
default:
return -EIO;
}
Index: linux-2.6/include/linux/usb_usual.h
===================================================================
--- linux-2.6.orig/include/linux/usb_usual.h 2008-02-05 09:42:23.000000000 +0100
+++ linux-2.6/include/linux/usb_usual.h 2008-03-13 21:20:33.000000000 +0100
@@ -83,6 +83,7 @@
#define US_SC_LOCKABLE 0x07 /* Password-protected */

#define US_SC_ISD200 0xf0 /* ISD200 ATA */
+#define US_SC_CYP_ATACB 0xf1 /* Cypress ATACB */
#define US_SC_DEVICE 0xff /* Use device's value */

/* Protocols */

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