linux-toradex.git/drivers/usb/core/message.c, branch v4.11

usb: core: update comments for send message functions

2017-01-19T09:34:40+00:00

The commonly use of bottom halves are tasklet and workqueue. The big
difference between tasklet and workqueue is that the tasklet runs in
an interrupt context and the workqueue runs in a process context,
which means it can sleep if need be.

The comment for usb_control/interrupt/bulk_msg() functions note that do
not use this function within an interrupt context, like a 'bottom half'
handler. With this comment, it makes confuse about usage of these
functions.

To more clarify, remove 'bottom half' comment.

Signed-off-by: Jaejoong Kim 
Signed-off-by: Greg Kroah-Hartman

USB: core: add missing license information to some files

2016-10-29T16:51:56+00:00

Some of the USB core files were missing explicit license information.
As all files in the kernel tree are implicitly licensed under the
GPLv2-only, be explicit in case someone get confused looking at
individual files by using the SPDX nomenclature.

Signed-off-by: Greg Kroah-Hartman

usb: core: setup dma_pfn_offset for USB devices and, interfaces

2016-09-13T15:25:35+00:00

If dma_pfn_offset is not inherited correctly from the host controller,
it might result in sub-optimal configuration as bounce
buffer limit might be set to less than optimal level.

Consider the mass storage device case.
USB storage driver creates a scsi host for the mass storage interface in
drivers/usb/storage/usb.c
The scsi host parent device is nothing but the the USB interface device.
Now, __scsi_init_queue() calls scsi_calculate_bounce_limit() to find out
and set the block layer bounce limit.
scsi_calculate_bounce_limit() uses dma_max_pfn(host_dev) to get the
bounce_limit. host_dev is nothing but the device representing the
mass storage interface.
If that device doesn't have the right dma_pfn_offset, then dma_max_pfn()
is messed up and the bounce buffer limit is wrong.

e.g. On Keystone 2 systems, dma_max_pfn() is 0x87FFFF and dma_mask_pfn
is 0xFFFFF. Consider a mass storage use case: Without this patch,
usb scsi host device (usb-storage) will get a dma_pfn_offset of 0 resulting
in a dma_max_pfn() of 0xFFFFF within the scsi layer
(scsi_calculate_bounce_limit()).
This will result in bounce buffers being unnecessarily used.

Hint: On 32-bit ARM platforms dma_max_pfn() = dma_mask_pfn + dma_pfn_offset

Signed-off-by: Roger Quadros 
Acked-by: Arnd Bergmann 
Acked-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

usb: core: message: don't print on ENOMEM

2016-08-30T17:17:36+00:00

All kmalloc-based functions print enough information on failures.

Signed-off-by: Wolfram Sang 
Signed-off-by: Greg Kroah-Hartman

usbnet: move the CDC parser into USB core

2016-07-18T15:46:57+00:00

The dependencies were impossible to handle preventing
drivers for CDC devices not which are not network drivers
from using the common parser.

Signed-off-by: Oliver Neukum 
Signed-off-by: Greg Kroah-Hartman

drivers: usb: core: Minimize irq disabling in usb_sg_cancel()

2016-04-26T22:21:41+00:00

Restructure usb_sg_cancel() so we don't have to disable interrupts
while cancelling the URBs.

Suggested-by: Alan Stern 
Signed-off-by: David Mosberger 
Signed-off-by: Greg Kroah-Hartman

drivers: usb: core: Don't disable irqs in usb_sg_wait() during URB submit.

2016-04-26T22:21:41+00:00

usb_submit_urb() may take quite long to execute.  For example, a
single sg list may have 30 or more entries, possibly leading to that
many calls to DMA-map pages.  This can cause interrupt latency of
several hundred micro-seconds.

Avoid the problem by releasing the io->lock spinlock and re-enabling
interrupts before calling usb_submit_urb().  This opens races with
usb_sg_cancel() and sg_complete().  Handle those races by using
usb_block_urb() to stop URBs from being submitted after
usb_sg_cancel() or sg_complete() with error.

Note that usb_unlink_urb() is guaranteed to return -ENODEV if
!io->urbs[i]->dev and since the -ENODEV case is already handled,
we don't have to check for !io->urbs[i]->dev explicitly.

Before this change, reading 512MB from an ext3 filesystem on a USB
memory stick showed a throughput of 12 MB/s with about 500 missed
deadlines.

With this change, reading the same file gave the same throughput but
only one or two missed deadlines.

Signed-off-by: David Mosberger 
Signed-off-by: Greg Kroah-Hartman

usb: message: remove redundant declaration

2015-10-04T09:45:11+00:00

Fix the Sparse warning:

message.c:1390:21: warning: symbol 'i' shadows an earlier one
message.c:1294:13: originally declared here

Signed-off-by: Kris Borer 
Signed-off-by: Greg Kroah-Hartman

usb: interface authorization: Introduces the USB interface authorization

2015-09-22T19:08:40+00:00

The kernel supports the device authorization because of wireless USB.
These is usable for wired USB devices, too.
These new interface authorization allows to enable or disable
individual interfaces instead a whole device.

If a deauthorized interface will be authorized so the driver probing must
be triggered manually by writing INTERFACE to /sys/bus/usb/drivers_probe

Signed-off-by: Stefan Koch 
Signed-off-by: Greg Kroah-Hartman

usb: interface authorization: Introduces the default interface authorization

2015-09-22T19:08:40+00:00

Interfaces are allowed per default.
This can disabled or enabled (again) by writing 0 or 1 to
/sys/bus/usb/devices/usbX/interface_authorized_default

Signed-off-by: Stefan Koch 
Signed-off-by: Greg Kroah-Hartman