Status provides sop_revision. Process it, and set it using the new
setter in the typec class.
Signed-off-by: Benson Leung <bleung@chromium.org>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Prashant Malani <pmalani@chomium.org>
Link: https://lore.kernel.org/r/20210129061406.2680146-6-bleung@chromium.orgSigned-off-by: Benson Leung <bleung@chromium.org>

cros_typec_handle_sop_prime_disc now takes the PD revision provided
by the EC_CMD_TYPEC_STATUS command response for the SOP'.

Attach the properly formatted pd_revision to the cable desc before
registering the cable.
Signed-off-by: Benson Leung <bleung@chromium.org>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Prashant Malani <pmalani@chromium.org>
Link: https://lore.kernel.org/r/20210129061406.2680146-5-bleung@chromium.orgSigned-off-by: Benson Leung <bleung@chromium.org>

Merge remote-tracking branch 'origin/cros-ec-typec-for-5.12' into ib-usb-typec-chrome-platform-cros-ec-typec-changes-for-5.12

The partner's PD revision may be resolved later than the port partner
registration since the port partner creation may take place once
Type-C detects the port has changed state, but before PD communication is
completed.

Add a setter so that the partner's PD revision can be attached to it once
it becomes available.

If the revision is set to a valid version (not 0), the setter will also
refresh the partner's usb_pd flag and notify on "supports_usb_power_delivery"
sysfs property as well.
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Benson Leung <bleung@chromium.org>
Link: https://lore.kernel.org/r/20210129061406.2680146-4-bleung@chromium.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The USB Power Delivery specification Section 6.2.1.1.5 outlines
revision backward compatibility requirements starting from Revision 3.0.

The Port, the Cable Plug, and the Port Partner may support either
revision 2 or revision 3 independently, and communication between ports,
partners, and cables of different revisions are allowed under rules
that the parties agree to communicate between each other using the
lowest common operating revision.

This may mean that Port-to-Partner operating revision comms may be
different than Port-to-CablePlug operating revision comms. For example,
it is possible for a R3.0 port to communicate with a R3.0 partner
using R3.0 messages, while the R3.0 port (in the same session) must
communicate with the R2.0 cable using R2.0 messages only.

Introduce individual revision number properties for cable
and port partner so that the port can track them independently.
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Benson Leung <bleung@chromium.org>
Link: https://lore.kernel.org/r/20210129061406.2680146-3-bleung@chromium.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The Type-C Revision was in a specific BCD format "0120H" for 1.2.
USB PD revision numbers follow a similar pattern with "0300H" for 3.0.

Standardizes the sysfs format for usb_power_delivery_revision
to align with the BCD format used for usb_typec_revision.

Example values:
- "2.0": USB Power Delivery Release 2.0
- "3.0": USB Power Delivery Release 3.0
- "3.1": USB Power Delivery Release 3.1
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Benson Leung <bleung@chromium.org>
Link: https://lore.kernel.org/r/20210129061406.2680146-2-bleung@chromium.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

If we receive a transfer event indicating that an endpoint should be
halted, but current endpoint state doesn't match it, then the halt might
be just resolved by the stop endpoint completion handler that detects the
halted endpoint due to a context state error.

In this case the TD we halted on is already moved to the cancelled TD list,
and should not be successfully completed and given back anymore.
Let the stop endpoint completion handler reset the endpoint, and then let
the reset endpoint handler give back the cancelled TD among all other
ones on the cancelled TD list
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-28-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

A halted endpoint can be detected both when transfer events complete, and
in stop endpoint command completion. Both these handlers will start
clearing up the halted endpoint and queue a reset endpoint command.

It's possible to get both events for the same halted endpoint if right
after a URB cancel queues a stop endpoint command the endpoint stalls.
Use the EP_HALTED flag to prevent resetting the endpoint twice.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-27-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

xhci_find_new_dequeue_state() and xhci_queue_new_dequeue_state() are no
longer used afer introducing the move_dequeue_past_td() function.

also remove struct xhci_dequeue_state as its no longer used.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-26-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace xhci_find_new_dequeue_state() and xhci_queue_new_dequeue_state()
functions with one combined function.
These function were always called after each other, and had a lot of extra
code just to pass the newly found dequeue state from the first function
to the other.

The new function also returns error in case there is a failure to
queue the new dequeue state. This way the caller can decide on
recovery measures to handle it.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-25-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Handle race where a stop endpoint command fails with "context state error"
as hardware hasn't actually started the ring yet after a previous urb
cancellation completed and restarted the endpoint.
Flushing the doorbell write that restart the endpoint reduced these cases,
but didn't completely resolve them.

Check if the ring is running in the stop endpoint completion handler, and
issue a new stop endpoint command in this case.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-24-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

xhci 4.6.9: "A busy endpoint may asynchronously transition from the
Running to the Halted or Error state due to error conditions detected
while processing TRBs. A possible race condition may occur if software,
thinking an endpoint is in the running state, issues a Stop Endpoint
Command, however at the same time the xHC asynchronously transitions
the endpoint to the Halted or Error state. In this case, a Context
State Error may be generated for the command completion. Software
may verify that this case occurred by inspecting the EP State for
Halted or Error when a Stop Endpoint Command results in a Context
State Error."

Halted endpoints were not detected or handled at all in the stop endpoint
completion handler. A set TR Deq ptr command was bluntly queued instead
of resetting the endpoint first. The set TR Deq command would fail with
a context state error.

Fix this case by resetting the halted endpoint first to get it to a
stopped state instead of the halted (error) state.
Handle cancelled TDs once endpoint reset completes,
invalidating cancelled TDs on ring either by turning them to no-op,
or in case ring stopped on cancelled TD then move hardware dequeue pointer
past it, which will clear the cancelled TD from hw cache, and make sure
HW does not process it
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-23-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Don't queue both a reset endpoint command and a
set TR deq command at once when handling a halted endpoint.

split this into two steps.
Initially only queue a reset endpoint command, and then if needed queue a
set TR deq command in the reset endpoint handler.

Note: This removes the RESET_EP_QUIRK handling which was added in
commit ac9d8fe7 ("USB: xhci: Add quirk for Fresco Logic xHCI hardware.")

This quirk was added in 2009 for prototype xHCI hardware meant for
evaluation purposes only, and should not reach consumers.
This hardware could not handle two commands queued at once, and had
bad data in the output context after a reset endpoint command.

After this patch two command are no longer queued at once, so that
part is solved  in this rewrite, but the workaround for bad data in the
output context solved by issuing an extra configure endpoint command is
bluntly removed.

Adding this workaround to the new rewrite just adds complexity, and I
think it's time to let this quirk go.
Print a debug message instead.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-22-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Halted endpoints can be discoverd both when handling transfer events and
command completion events. Move code that handles halted endpoints before
both of those event handlers.

Rename the function to xhci_handle_halted_ep() to better describe
what it does. Try to reserve "cleanup" word in function names for last
stage cleanup activities.

No functional changes
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-21-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Refactor handler for stop endpoint command completion. Yank out the part
that invalidates cancelled TDs and turn it into a separate function.

Invalidating cancelled TDs should be done while the ring is stopped,
but not exclusively in the stop endpoint command completeion handler.

We will need to invalidate TDs after resetting endpoints as well.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-20-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In cases where the TD can't be given back in current handler we want
to be able to store it until its time to return the TD.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-19-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

use the existing xhci_td_cleanup() to give back cancelled TDs when a
ring is stopped.

A minor change to make sure we don't try to remove an already removed
td from the list is needed as cancelled TDs are already removed from the
td_list immediatelty when it's cancelled.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-18-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

No funtional changes
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-17-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Create a separate helper function to issue reset endpont commands
to clear halted endpoints.

This is useful for cases where a halted endpoint is discovered while
completing another command, and the endpoint halt needs to be cleared
with a endpoint reset first.

No functional changes
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-16-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Stop endpoint command fails with "context state error" if the endpoint is
already stopped.

This case was observed when a previous URB cancel had just completed and
rang the doorbell to restart the ring, when a new URB cancel queued a stop
endpoint command.
>From xHC hardware pov the endpoint had not yet started, so the stop
endpoint command failed with context state error.
Right after this the doorbell ring took effect and ring was restarted.

Interrupt handler saw a stop endpoint command completion event with
"context state error" and discovered that the ring was back up in
running state.

flushing the write reduces these cases in stress testing, but does not
completely remove the issue.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-15-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

xhci driver relies on link TRBs existing in the correct places in TRB
ring buffers shared with the host controller.
The controller should not modify these link TRBs, but in theory a faulty
xHC could do it.

Add some basic sanity checks to avoid infinite loops in interrupt handler,
or accessing unallocated memory outside a ring segment due to missing or
misplaced link TRBs.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-14-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of re-reading, masking and endianness correcting the same trb
several times to get the trb type from an event, just do it once and
store it in a local variable.

Also pass the trb_type directly to the vendor specific event handler,
avoiding one more similar read.

In addition to the security benefit this also cleans up the code
and helps readability.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-13-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When finishing a TD we walk the endpoint dequeue trb pointer
until it matches the last TRB of the TD.

TDs can contain over 100 TRBs, meaning we call a function 100 times,
do a few comparisons and increase a couple values for each of these calls,
all in interrupt context.

This can all be avoided by adding a pointer to the last TRB segment, and
a number of TRBs in the TD. So instead of walking through each TRB just
set the new dequeue segment, pointer, and number of free TRBs directly.

Getting rid of the while loop also reduces the risk of getting stuck in a
infinite loop in the interrupt handler. Loop relied on valid matching
dequeue and last_trb values to break.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-12-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Check that the slot_id that we dug out from command completion event
TRB, is valid before using it to identify the slot associated with the
command that generated the event.
Signed-off-by: Lalithambika Krishna Kumar <lalithambika.krishnakumar@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-11-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

xhci driver links together segments in a ring buffer by turning the last
TRB of a segment into a link TRB, pointing to the beginning of
the next segment.

If the first TRB of every segment for some unknown reason is a link TRB
pointing to the next segment, then prepare_ring() loops indefinitely.
This isn't something the xhci driver would do.
xHC hardware has access to these rings, it sholdn't be writing link
TRBs either, but with broken xHC hardware this could in theory be
possible.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-10-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The one case that used this function can use the
xhci_triad_to_transfer_ring() helper instead.

Avoid having several functions doing basically the same thing.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-9-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Two existing ring helpers, xhci_triad_to_transfer_ring() and
xhci_stream_id_to_ring() have partially similar functionality.
Both have some limitation, especieally with boundary checking.

Add a new xhci_virt_ep_to_ring() helper with proper boundary checking
that can replace parts of one helper, and later will completely
replace the other helper.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-8-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Check that the xhci_virt_dev structure that we dug out based
on a slot_id value from a command completion is valid before
dereferencing it.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-7-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In several event handlers we need to find the right endpoint
structure from slot_id and ep_index in the event.

Add a helper for this, check that slot_id and ep_index are valid.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-6-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

several command completion handlers are passed the event trb
as a paramtere even if it't not used.
Remove it.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-5-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of passing slot id and endpoint index to
cleanup_halted_endpoint() pass the endpoint structure pointer
as it's already known.

Avoids again digging out the endpoint structure based on
slot id and endpoint index, and passing them along the
call chain for this purpose only.

Add slot_id to the virt_dev structure so that it
can easily be found from a virt_dev, or its child, the
virt_ep endpoint structure.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-4-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

isochronous endpoints do not support streams, meaning that
there is only one ring per endpoint.

Avoid double-fetching the transfer event DMA to get the
ring. Also makes passing the event to skip_isoc_td() uncecessary.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-3-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When handling transfer events the event is passed along the handling
callpath and parsed again in several occasions.

The event contains slot_id and endpoint index, from which the driver
endpoint structure can be found. There wasn't however a way to get the
endpoint index or parent usb device from this endpoint structure.

A lot of extra event parsing, and thus some DMA doublefetch cases,
and excess variables and code can be avoided by adding endpoint index
and parent usb virt device pointer to the endpoint structure.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-2-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

With some USB network adapters, such as DM96xx, the following message
is seen for each maximum size receive packet.

dwc2 ff540000.usb: dwc2_update_urb_state(): trimming xfer length

This happens because the packet size requested by the driver is 1522
bytes, wMaxPacketSize is 64, the dwc2 driver configures the chip to
receive 24*64 = 1536 bytes, and the chip does indeed send more than
1522 bytes of data. Since the event does not indicate an error condition,
the message is just noise. Demote it to debug level.

Fixes: 7359d482 ("staging: HCD files for the DWC2 driver")
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20210113112052.17063-4-nsaenzjulienne@suse.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In some situations, the following error messages are reported.

dwc2 ff540000.usb: dwc2_hc_chhltd_intr_dma: Channel 1 - ChHltd set, but reason is unknown
dwc2 ff540000.usb: hcint 0x00000002, intsts 0x04000021

This is sometimes followed by:

dwc2 ff540000.usb: dwc2_update_urb_state_abn(): trimming xfer length

and then:

WARNING: CPU: 0 PID: 0 at kernel/v4.19/drivers/usb/dwc2/hcd.c:2913
			dwc2_assign_and_init_hc+0x98c/0x990

The warning suggests that an odd buffer address is to be used for DMA.

After an error is observed, the receive buffer may be full
(urb->actual_length >= urb->length). However, the urb is still left in
the queue unless three errors were observed in a row. When it is queued
again, the dwc2 hcd code translates this into a 1-block transfer.
If urb->actual_length (ie the total expected receive length) is not
DMA-aligned, the buffer pointer programmed into the chip will be
unaligned. This results in the observed warning.

To solve the problem, abort input transactions after an error with
unknown cause if the entire packet was already received. This may be
a bit drastic, but we don't really know why the transfer was aborted
even though the entire packet was received. Aborting the transfer in
this situation is less risky than accepting a potentially corrupted
packet.

With this patch in place, the 'ChHltd set' and 'trimming xfer length'
messages are still observed, but there are no more transfer attempts
with odd buffer addresses.

Fixes: 151d0cbd ("usb: dwc2: make the scheduler handle excessive NAKs better")
Cc: Boris ARZUR <boris@konbu.org>
Cc: Douglas Anderson <dianders@chromium.org>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20210113112052.17063-3-nsaenzjulienne@suse.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The DWC2 documentation states that transfers with zero data length should
set the number of packets to 1 and the transfer length to 0. This is not
currently the case for inbound transfers: the transfer length is set to
the maximum packet length. This can have adverse effects if the chip
actually does transfer data as it is programmed to do. Follow chip
documentation and keep the transfer length set to 0 in that situation.

Fixes: 56f5b1cf ("staging: Core files for the DWC2 driver")
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20210113112052.17063-2-nsaenzjulienne@suse.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Trivial example fix.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/8fa5edcaa6b93859cfda97d080aad378e89c1b44.1611232967.git.michal.simek@xilinx.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Update Raw Gadget documentation and Kconfig. Make the description more
precise and clear, fix typos and grammar mistakes, and do other cleanups.
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Link: https://lore.kernel.org/r/f4c650c94ae2b910e38819d51109cd5f0b251a2a.1611429174.git.andreyknvl@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add copyright to drivers/usb/gadget/legacy/raw_gadget.c.
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Link: https://lore.kernel.org/r/c8937266c4a5da073ac81cd471b18d869c984dfe.1611429174.git.andreyknvl@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Tasklets have long been deprecated as being too heavy on the system
by running in irq context - and this is not a performance critical
path. If a higher priority process wants to run, it must wait for
the tasklet to finish before doing so.

c67x00_do_work() will now run in process context and have further
concurrency (tasklets being serialized among themselves), but this
is done holding the c67x00->lock, so it should be fine. Furthermore,
this patch fixes the usage of the lock in the callback as otherwise
it would need to be irq-safe.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20210113031537.79859-1-dave@stgolabs.netSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>