[PATCH 2/3] usb: storage: add support write cache quirk on usb hdd

From: Namjae Jeon
Date: Wed Jun 06 2012 - 08:20:59 EST


Add support write cache quirk on usb hdd. scsi driver will be set to wce by detecting write cache quirk in quirk list when plugging usb hdd.

Signed-off-by: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
Signed-off-by: Pankaj Kumar <pankaj.km@xxxxxxxxxxx>
Signed-off-by: Amit Sahrawat <a.sahrawat@xxxxxxxxxxx>
---
drivers/usb/storage/scsiglue.c | 6 ++++++
drivers/usb/storage/usb.c | 5 ++++-
include/linux/usb/quirks.h | 3 +++
include/linux/usb_usual.h | 4 +++-
4 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index a324a5d..f7d0ea5 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -51,6 +51,7 @@
#include <scsi/scsi_devinfo.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
+#include <linux/usb/quirks.h>

#include "usb.h"
#include "scsiglue.h"
@@ -230,6 +231,11 @@ static int slave_configure(struct scsi_device *sdev)
US_FL_SCM_MULT_TARG)) &&
us->protocol == USB_PR_BULK)
us->use_last_sector_hacks = 1;
+
+ /* Check for the cache quirk present or not */
+ if (us->pusb_dev->quirks & USB_QUIRK_WRITE_CACHE ||
+ us->fflags & US_FL_WRITE_CACHE)
+ sdev->wce_quirk = 1;
} else {

/* Non-disk-type devices don't need to blacklist any pages
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index e23c30a..062d7d5 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -473,7 +473,7 @@ static void adjust_quirks(struct us_data *us)
US_FL_CAPACITY_OK | US_FL_IGNORE_RESIDUE |
US_FL_SINGLE_LUN | US_FL_NO_WP_DETECT |
US_FL_NO_READ_DISC_INFO | US_FL_NO_READ_CAPACITY_16 |
- US_FL_INITIAL_READ10);
+ US_FL_INITIAL_READ10 | US_FL_WRITE_CACHE);

p = quirks;
while (*p) {
@@ -538,6 +538,9 @@ static void adjust_quirks(struct us_data *us)
case 'w':
f |= US_FL_NO_WP_DETECT;
break;
+ case 'p':
+ f |= US_FL_WRITE_CACHE;
+ break;
/* Ignore unrecognized flag characters */
}
}
diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h
index 3e93de7..9a3c8ab 100644
--- a/include/linux/usb/quirks.h
+++ b/include/linux/usb/quirks.h
@@ -30,4 +30,7 @@
descriptor */
#define USB_QUIRK_DELAY_INIT 0x00000040

+/* Device can't handle cache status request */
+#define USB_QUIRK_WRITE_CACHE 0x00000080
+
#endif /* __LINUX_USB_QUIRKS_H */
diff --git a/include/linux/usb_usual.h b/include/linux/usb_usual.h
index 17df360..f8fdcbf 100644
--- a/include/linux/usb_usual.h
+++ b/include/linux/usb_usual.h
@@ -64,7 +64,9 @@
US_FLAG(NO_READ_CAPACITY_16, 0x00080000) \
/* cannot handle READ_CAPACITY_16 */ \
US_FLAG(INITIAL_READ10, 0x00100000) \
- /* Initial READ(10) (and others) must be retried */
+ /* Initial READ(10) (and others) must be retried */ \
+ US_FLAG(WRITE_CACHE, 0x00200000) \
+ /* Cache read status is not correct */

#define US_FLAG(name, value) US_FL_##name = value ,
enum { US_DO_ALL_FLAGS };
--
1.7.9.5

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