Add support for 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 | 5 +++++
drivers/usb/storage/usb.c | 5 ++++-
include/linux/usb_usual.h | 4 +++-
3 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c[...]
index a324a5d..fe42547 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -529,6 +529,9 @@ static void adjust_quirks(struct us_data *us)
case 'o':
f |= US_FL_CAPACITY_OK;
break;
+ case 'p':
+ f |= US_FL_WRITE_CACHE;
+ break;
case 'r':
f |= US_FL_IGNORE_RESIDUE;
break;
diff --git a/include/linux/usb_usual.h b/include/linux/usb_usual.h
index 17df360..96fc152 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) \
+ /* Write Cache status is not available */
#define US_FLAG(name, value) US_FL_##name = value ,
enum { US_DO_ALL_FLAGS };