This patch reworks the way f_mass_storage.c handles memory barriers
and synchronization:
The driver now uses a wait_queue instead of doing its own
task-state manipulations (even though only one task will ever
use the wait_queue).
The thread_wakeup_needed variable is removed. It was only a
source of trouble; although it was what the driver tested to
see whether it should wake up, what we really wanted to see
was whether a USB transfer had completed.
All the explicit memory barriers scattered throughout the
driver are replaced by a few calls to smp_load_acquire() and
smp_store_release().
The inreq_busy and outreq_busy fields are removed. In their
place, the driver keeps track of the current I/O direction by
splitting BUF_STATE_BUSY into two states: BUF_STATE_SENDING
and BUF_STATE_RECEIVING.
The buffer states are no longer protected by a lock. Mutual
exclusion isn't needed; the state is changed only by the
driver's main thread when it owns the buffer, and only by the
request completion routine when the gadget core owns the buffer.
The do_write() and throw_away_data() routines were reorganized
to make efficient use of the new sleeping mechanism. This
resulted in the removal of one indentation level in those
routines, making the patch appear to be more more complicated
than it really is.
In a few places, the driver allowed itself to be frozen although
it really shouldn't have (in the middle of executing a SCSI
command). Those places have been fixed.
The logic in the exception handler for aborting transfers and
waiting for them to stop has been simplified.
Tested-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This patch makes several adjustments to the way f_mass_storage.c
handles its internal state and asynchronous notifications (AKA
exceptions):
A number of states weren't being used for anything.
They are removed.
The FSG_STATE_IDLE state was renamed to FSG_STATE_NORMAL,
because it now applies whenever the gadget is operating
normally, not just when the gadget is idle.
The FSG_STATE_RESET state was renamed to
FSG_STATE_PROTOCOL_RESET, indicating that it represents a
Bulk-Only Transport protocol reset and not a general USB
reset.
When a signal arrives, it's silly for the signal handler to
send itself another signal! Now it takes care of everything
inline.
Along with an assortment of other minor changes in the same category.
Tested-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Introduce an attribute "inquiry_string" to the lun.
In some environments, e. g. BIOS boot menus, the inquiry string
is the only information about devices presented to the user. The
default string depends on the "cdrom" bit of the first lun as
well as the kernel version and allows no further customization.
So without access to the client it is not obvious which gadget is
active at a given point and what any of the available luns might
contain.
If "inquiry_string" is ignored or set to the empty string, the
old behavior is preserved.
Signed-off-by: Philipp Gesang <philipp.gesang@intra2net.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Mass storage spec allows up to 16 LUNs, so let's not
add some more restrictive limits.
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
The drivers/usb/gadget directory contains many files.
Files which are related can be distributed into separate directories.
This patch moves the USB functions implementations into a separate directory.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
