usb: musb: cppi41: Switch to use dev_err_probe() helper

In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs. It's more simple in error path.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220927072616.913672-4-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb/musb: fix repeated words in comments

Delete the redundant word 'mode'.
Delete the redundant word 'than'.

Signed-off-by: Jilin Yuan <yuanjilin@cdjrlc.com>
Link: https://lore.kernel.org/r/20220716134457.46535-1-yuanjilin@cdjrlc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: remove duplicated quirks flag

Both musb_io and musb_platform_ops in struct musb define a quirks flag
for the same purpose. Let's remove the one in struct musb_io, and use
that in struct musb_platform_ops instead.

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: add SPDX identifiers to all remaining files in drivers/usb/

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/usb/ and include/linux/usb* files with the correct
SPDX license identifier based on the license text in the file itself.
The SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: musb_cppi41: Configure the number of channels for DA8xx

Currently, the number of channels is set to 15 but in the case of DA8xx,
the number of channels is 4.
Update the driver to configure the number of channels at runtime.

Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Tested-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: musb_cppi41: Fix cppi41_set_dma_mode() for DA8xx

The way to configure the DMA mode on DA8xx is different from DSPS.
Add a new function to configure DMA mode on DA8xx and use a callback
to call the right function based on the platform.

Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Tested-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: musb_cppi41: Fix the address of teardown and autoreq registers

The DA8xx and DSPS platforms don't use the same address for few registers.
On Da8xx, this is causing some issues (e.g. teardown that doesn't work).
Configure the address of the register during the init and use them instead
of constants.

Cc: stable@vger.kernel.org # v4.12+
Reported-by: nsekhar@ti.com
Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Tested-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: musb_cppi41: Defer probe only if DMA is not ready

If dma_request_slave_channel() failed to return a channel,
then the driver will print an error and request to defer probe,
regardless of the cause of the failure.
Defer if the DMA is not ready yet otherwise print an error.

Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: musb_cppi41: Workaround DMA stall issue during teardown

The DMA may hang up if a teardown is initiated while an endpoint is still
active (Advisory 2.3.27 of DA8xx errata).
To workaround this issue, add a delay before to initiate the teardown.

Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: cppi41: don't check early-TX-interrupt for Isoch transfer

The CPPI 4.1 driver polls register to workaround the premature TX
interrupt issue, but it causes audio playback underrun when triggered in
Isoch transfers.

Isoch doesn't do back-to-back transfers, the TX should be done by the
time the next transfer is scheduled. So skip this polling workaround for
Isoch transfer.

Fixes: a655f481d83d6 ("usb: musb: musb_cppi41: handle pre-mature TX complete interrupt")
Cc: <stable@vger.kernel.org> #4.1+
Reported-by: Alexandre Bailon <abailon@baylibre.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Alexandre Bailon <abailon@baylibre.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: cppi_dma: Clean up cppi41_dma_controller structure

A pointer to musb is now present in the dma_controller structure.
Remove the one present in cppi41_dma_controller structure.

Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: cppi41: Detect aborted transfers in cppi41_dma_callback()

Update cppi41_dma_callback() to detect an aborted transfer.
This was not required before because cppi41_dma_callback() was only
invoked on transfer completion.
In order to make CPPI 4.1 driver more generic, cppi41_dma_callback()
will be invoked after a transfer abort in order to let the MUSB driver
perform some action such as acknowledge the interrupt that may be fired
during a teardown.

Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: dma: Add a DMA completion platform callback

Currently, the CPPI 4.1 driver is not completely generic and
only works on DSPS. This is because of IRQ management.
Add a callback to dma_controller that could be invoked on DMA completion
to acknowledge the IRQ.

Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ktime: Cleanup ktime_set() usage

ktime_set(S,N) was required for the timespec storage type and is still
useful for situations where a Seconds and Nanoseconds part of a time value
needs to be converted. For anything where the Seconds argument is 0, this
is pointless and can be replaced with a simple assignment.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

usb: musb: cppi41: add dma channel tracepoints

Add tracepoints for cppi41 dma channels.

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: cppi41: move struct cppi41_dma_channel to header

Move struct cppi41_dma_channel to the header file so other modules can
use it.

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: switch dev_dbg to tracepoints

Switch dev_dbg() to tracepoint debug musb_dbg().

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: fix cppi channel teardown for isoch transfer

After a few iterations of start/stop UVC camera streaming, the streaming
stops.

This patch adds 250us delay in the cppi channel abort path to let cppi
drain properly.

Using 50us delay seems to be too aggressive, some webcams are still
broken. 250us is the original value used in TI 3.2 kernel.

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: allow it to work again

since commit 33c300cb90a6 ("usb: musb: dsps:
don't fake of_node to musb core") we have been
preventing CPPI 4.1 from probing due to NULL
of_node. We can't revert said commit otherwise
a different regression would show up, so the fix
is to look for the parent device's (glue layer's)
of_node instead, since that's the thing which
is actually described in DTS.

Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: Set up function pointers for DMA

Set up function pointers for DMA so get closer to
being able to build in all the DMA engines.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: fix condition to call cppi41_trans_done().

connect AR9271(USB wifi) to AM335x, and send a flood ping from Mac OSX,
AR9271 is stopped.

on USB bus, the following occurs.

- OUT transaction is ACKed (NYET).
- IN transaction is ACKed (512bytes).
- PING-NAK transaction is continued for about 2 seconds (AR9271 timeout?).

In current imprementation, IN-transaction is not completed because it
checks the empty of TX-FIFO in cppi41_dma_callback().
As a result, communication to AR9271 stops.

This patch modified to check the empty of TX-FIFO only when OUT-transaction.

Signed-off-by: Takeyoshi Kikuchi <kikuchi@centurysys.co.jp>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: do not call udelay()

according to comment in code, HS completion
will happen pretty fast, instead of using
udelay(), let's just busy loop and drop a
cpu_relax() where udelay() was.

Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: exit early when tx fifo is empty

as soon as we find out tx fifo is empty, there's
no need to break out of the loop just to have another
branch to complete the transfer. We can just complete
transfer and exit early.

Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: decrease indentation level

no functional changes, clean up only.

Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: improve rx channel abort routine

1. set AUTOREQ to NONE at the beginning of teardown;

2. add delay for dma pipeline to drain;

3. Do not set USB_TDOWN bit for RX teardown.

The CPPI hw has an issue that when tearing down a RX channel, if
another RX channel is receiving data, the CPPI will lockup.

To workaround the issue, do not set the CPPI TD bit. The steps before
this point ensures the CPPI channel will be torn down properly.

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: correct the macro name EP_MODE_AUTOREG_*

The macro EP_MODE_AUTOREG_* should be called EP_MODE_AUTOREQ_*, as they
are used for register AUTOREQ.

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: Fix a few off-by-one lengths

!strncmp(buf, "force host", 9) is true if and only if buf starts with
"force hos". This was obviously not what was intended. The same error
exists for "force full-speed", "force high-speed" and "test
packet". Using strstarts avoids the error-prone hardcoding of the
prefix length.

For consistency, also change the other occurences of the !strncmp
idiom.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: musb_cppi41: recognize HS devices in hostmode

There is a poll loop for max 25us for HS devices. Now guess what, I
tested it in gadget mode and forgot about the little detail. Nobody seem
to have it noticed…
This patch adds the missing logic for hostmode so it is recognized in
host and device mode properly.

Fixes: 50aea6fca771 ("usb: musb: cppi41: fire hrtimer according to
programmed channel length")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: restart hrtimer only if not yet done

commit c58d80f52 ("usb: musb: Ensure that cppi41 timer gets armed on
premature DMA TX irq") fixed hrtimer scheduling bug. There is one left
which does not trigger that often.
The following scenario is still possible:

lock(&x->lock);
hrtimer_start(&x->t);
unlock(&x->lock);

expires:
t->function();
lock(&x->lock);
lock(&x->lock); if (!hrtimer_queued(&x->t))
hrtimer_start(&x->t);
unlock(&x->lock);

if (!list_empty(x->early_tx_list))
ret = HRTIMER_RESTART;
-> hrtimer_forward_now(...)
} else
ret = HRTIMER_NORESTART;

unlock(&x->lock);

and the timer callback returns HRTIMER_RESTART for an armed timer. This
is wrong and we run into the BUG_ON() in __run_hrtimer().
This can happens on SMP or PREEMPT-RT.
The patch fixes the problem by only starting the timer if the timer is
not yet queued.

Cc: stable@vger.kernel.org
Reported-by: Torben Hohn <torbenh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bigeasy: collected information and created a patch + description based
on it]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: tweak hrtimer values

Intensive tests with USB audio devices connected to a musb host port
have shown reproducible pops and clicks in both the playback and the
capture stream.

These are related to how the early_tx hrtimer is set up, and it turns
out they can be fixed by reducing the timer's slack value from 40 to
25 us. Also, when the callback is ran without taking action, it should
be rescheduled 20 us later instead of 50 us.

Reported-and-tested-by: Sven Neumann <neumann@teufel.de>
Signed-off-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: fix not transmitting zero length packet issue

CPPI TX does not transmit ZLP for TX transfers which
- transfer size is multiple of EP packet size,
- and URB_ZERO_PACKET is set in urb->transfer_flags.

The fix is transmitting the ZLP using PIO mode after the CPPI TX is
done.

Validated using the following usbtest write case in MUSB host mode.

# testusb -t1 -c1

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: fire hrtimer according to programmed channel length

The musb/cppi41 code installs a hrtimer to work around DMA completion
interrupts that have fired too early on AM335x hardware. This timer
is currently programmed to first fire 140 microseconds after the DMA
completion callback. According to the commit which introduced it
(a655f481d83, "usb: musb: musb_cppi41: handle pre-mature TX complete
interrupt"), that value is is considered a 'rule of thumb' that worked
well with the test case described in the commit log.

Test show, however, that for USB audio devices and much smaller packet
sizes, the timer has to fire earlier in order to correctly handle the audio
stream. The original test case had output transfer sizes of 1514 bytes, and
a delay of 140 microseconds. For audio devices with 24 bytes channel size, 3
microseconds seem to work well.

Hence, let's assume that the time it takes to clear the bit correlates with
the number of bytes transferred. The referenced commit log mentions such a
suspicion as well. Let the timer fire in cppi41_channel->total_len/10
microseconds to correctly handle both cases.

Also, shorten the interval in which the timer fires again in case of
a non-empty early_tx list.

With these changes in place, both FS and HS audio devices appear to work
well on AM335x hardware.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Reported-by: Sebastian Reimers <sebastian.reimers@googlemail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Revert "usb: musb: musb_cppi41: Handle ISOCH differently and not use the hrtimer."

This reverts commit 1af54b7a4.

The commit tried to address cases in which isochronous transfers are 'not
reliable', most probably in the tests conducted, polling for the
MUSB_TXCSR_TXPKTRDY bit in MUSB_TXCSR is done too late.

Hence, it installs a work struct which basically busy-polls for the bit in a
rather agressive way by rescheduling the work if the FIFO is not empty. With
USB audio devices, tests have shown that it takes approximately 100
iterations of the asynchronous worker until the FIFO signals completion,
which leads to 100% CPU loads when streaming audio.

The issue the patch tried to address can be handled differently, which is
what the next patch does.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Reported-by: Sebastian Reimers <sebastian.reimers@googlemail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb/cppi41: call musb_ep_select() before accessing an endpoint's CSR

Before accessing any of an endpoint's CSR registers, make sure the
correct endpoint is selected. Otherwise, data read from or written to
the registers is likely to affect the wrong endpoint as long as the
connected device has more than one endpoint.

This, of course, leads to all sorts of strange effects such as stream
starvation and driver internal state machine confusion due to spurious
interrupts.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: introduce dma_channel.rx_packet_done

The musb/cppi41 glue layer is capable of handling transactions that span
over more than one USB packet by reloading the DMA descriptors
partially. An urb is considered completed when either its transfer
buffer has been filled entirely (actual_length ==
transfer_buffer_length) or if a packet in the stream has less bytes than
the endpoint's wMaxPacketSize.

Once one of the above conditions is met, musb_dma_completion() is called
from cppi41_trans_done(). However, the final decision whether or not to
return the urb to its owner is made by the core and its determination of
the variable 'done' in musb_host_rx(). This code has currently no way of
knowing what the size of the last packet was, and whether or not to
give back the urb due to a short read.

Fix this by introducing a new boolean flag in 'struct dma_channel', and
set it from musb_cppi41.c. If set, it will make the core do what the
DMA layer decided and complete the urb.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: Ensure that cppi41 timer gets armed on premature DMA TX irq

Some TI chips raise the DMA complete interrupt before the actual
transfer has been completed. The code tries to busy wait for a few
microseconds and if that fails it arms an hrtimer to recheck. So far
so good, but that has the following issue:

CPU 0 CPU1

start_next_transfer(RQ1);

DMA interrupt
if (premature_irq(RQ1))
if (!hrtimer_active(timer))
hrtimer_start(timer);

hrtimer expires
timer->state = CALLBACK_RUNNING;
timer->fn()
cppi41_recheck_tx_req()
complete_request(RQ1);
if (requests_pending())
start_next_transfer(RQ2);

DMA interrupt
if (premature_irq(RQ2))
if (!hrtimer_active(timer))
hrtimer_start(timer);
timer->state = INACTIVE;

The premature interrupt of request2 on CPU1 does not arm the timer and
therefor the request completion never happens because it checks for
!hrtimer_active(). hrtimer_active() evaluates:

timer->state != HRTIMER_STATE_INACTIVE

which of course evaluates to true in the above case as timer->state is
CALLBACK_RUNNING.

That's clearly documented:

* A timer is active, when it is enqueued into the rbtree or the
* callback function is running or it's in the state of being migrated
* to another cpu.

But that's not what the code wants to check. The code wants to check
whether the timer is queued, i.e. whether its armed and waiting for
expiry.

We have a helper function for this: hrtimer_is_queued(). This
evaluates:

timer->state & HRTIMER_STATE_QUEUED

So in the above case this evaluates to false and therefor forces the
DMA interrupt on CPU1 to call hrtimer_start().

Use hrtimer_is_queued() instead of hrtimer_active() and evrything is
good.

Reported-by: Torben Hohn <torbenh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: musb_cppi41: Dont reprogram DMA if tear down is initiated

Reprogramming the DMA after tear down is initiated leads to warning.
This is mainly seen with ISOCH since we do a delayed completion for
ISOCH transfers. In ISOCH transfers dma_completion should not reprogram
if the channel tear down is initiated.

Signed-off-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

usb: musb: musb_cppi41: Dont reprogram DMA if tear down is initiated

Reprogramming the DMA after tear down is initiated leads to warning.
This is mainly seen with ISOCH since we do a delayed completion for
ISOCH transfers. In ISOCH transfers dma_completion should not reprogram
if the channel tear down is initiated.

Signed-off-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: musb_cppi41: Handle ISOCH differently and not use the hrtimer.

In case of ISOCH transfers the hrtimer workaround for the hardware issue
is not very reliable. Instead of checking musb_is_tx_fifo_empty() in hrtimer
routine, schedule a completion work and check the same in completion work.

Signed-off-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: musb_cppi41: Make CPPI aware of high bandwidth transfers

Enable CPPI to handle high bandwidth transfers, especially to support
webcam captures. Use a single bd to get the whole of the data in case of
high bandwidth transfers.

Signed-off-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

USB: musb: correct spelling mistakes in comment and error string

Signed-off-by: Rahul Bedarkar <rahulbedarkar89@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: musb: musb_cppi41: handle pre-mature TX complete interrupt

The TX-complete interrupt of the CPPI41 on AM335x fires too early.
Adding a loop and counting how long it takes until the
MUSB_TXCSR_TXPKTRDY bit is cleared I see
FS:
|musb-hdrc musb-hdrc.0.auto: configure ep1/80 packet_sz=64, mode=0, dma_addr=0xadc54002, len=1514 is_tx=1
|cppi41_dma_callback() 74 loops
|musb-hdrc musb-hdrc.0.auto: configure ep1/80 packet_sz=64, mode=0, dma_addr=0xadcd8802, len=1514 is_tx=1
|cppi41_dma_callback() 66 loops
|musb-hdrc musb-hdrc.0.auto: configure ep1/80 packet_sz=64, mode=0, dma_addr=0xadcd8002, len=1514 is_tx=1
|cppi41_dma_callback() 136 loops
|musb-hdrc musb-hdrc.0.auto: configure ep1/80 packet_sz=64, mode=0, dma_addr=0xadf55802, len=1514 is_tx=1
|cppi41_dma_callback() 136 loops

avg: 110 - 150us

HS:
|musb-hdrc musb-hdrc.0.auto: configure ep1/80 packet_sz=512, mode=0, dma_addr=0xaca6f002, len=1514 is_tx=1
|cppi41_dma_callback() 0 loops
|musb-hdrc musb-hdrc.0.auto: configure ep1/80 packet_sz=512, mode=0, dma_addr=0xadd6f802, len=1514 is_tx=1
|cppi41_dma_callback() 2 loops
|musb-hdrc musb-hdrc.0.auto: configure ep1/80 packet_sz=512, mode=0, dma_addr=0xadd6f002, len=1514 is_tx=1
|cppi41_dma_callback() 13 loops

avg: 2us

for the same test case. One loop means a udelay(1). The delay seems to
depend on the packet size. On HS the bit is always cleared for small
packet sizes while on FS it is never the case, it mostly around 110us.
This testing has been performed with g_ether (musb as device) and using BULK
transfers.

INTR transfers are way more fun: during init the gadget sends a INT
packet to the host and cppi41 says "transfer done" shortly after. The
MUSB_TXCSR_TXPKTRDY bit is set even seconds later. The reason is that the host
did not try to receive it, it does so after the interface (on host side) has
been configured. Until this happens, that packet remains in musb's FIFO.

To fix this, two things are done:
- No DMA transfers for INT based endpoints. These transfer are usually
very small and rare so it is likely better to skip the DMA engine and
stuff the four bytes directly into the FIFO
- on HS we poll up to 25us and hope that bit goes away. If not we setup
a hrtimer to poll for it. The 140us delay is a rule of thumb. In FS
the command
| ping 10.10.10.10 -c1 -s65130
creates about 44 1514bytes transfers. About 19 of them need a second
timer to complete.

Reported-by: Bin Liu <b-liu@ti.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: musb_cppi41: factor most of cppi41_dma_callback() into cppi41_trans_done()

This patch moves most of the logic in cppi41_dma_callback() into
cppi41_trans_done() where it can be called from another function.
Instead of computing "transferred" (the number of bytes transferred in
the last transaction) in cppi41_trans_done() the member
"cppi41_channel->prog_len" is now set to 0 if the transfer as a whole
can be considered as done. If it is != 0 then the next iteration is
assumed.
This is a preparation for a workaround.

Cc: stable@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: allow to defer probing if DMA isn't yet available

If everything (musb, cppi41, phy) is built-in then musb will start
without the dma engine printing only

|musb-hdrc musb-hdrc.0.auto: Falied to request rx1.

The reason for this is that the musb device structs are created & probed
before those of the cppi41 device. So the cppi41 device is probed too
late.
As a workaround for this allow the musb_cppi41 part to defer the probe
if everything is fine except for the missing DMA controller. In case of
another error we continue.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: fix missing unlock on error in cppi41_dma_callback()

Add the missing unlock before return from function cppi41_dma_callback()
in the error handling case.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb: cppi41: Enable in device-TX mode

Since the musb-gadget code now calls the dma engine properly it is
possible to enable it for the TX path in device mode.
AM335x Advisory 1.0.13 says that we may lose the toggle bit on multiple
RX transfers. There is a workaround in host mode but none in device mode
and therefore RX transfers are disabled.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

usb: musb dma: add cppi41 dma driver

This driver is currently used by musb' cppi41 couter part. I may merge
both dma engine user of musb at some point but not just yet.

The driver seems to work in RX/TX mode in host mode, tested on mass
storage. I increaed the size of the TX / RX transfers and waited for the
core code to cancel a transfers and it seems to recover.

v2..3:
- use mall transfers on RX side and check data toggle.
- use rndis mode on tx side so we haveon interrupt for 4096 transfers.
- remove custom "transferred" hack and use dmaengine_tx_status() to
compute the total amount of data that has been transferred.
- cancel transfers and reclaim descriptors

v1..v2:
- RX path added
- dma mode 0 & 1 is working
- device tree nodes re-created.

Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <djbw@fb.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>