usb: mtu3: fix kernel panic at qmu transfer done irq handler

When handle qmu transfer irq, it will unlock @mtu->lock before give back
request, if another thread handle disconnect event at the same time, and
try to disable ep, it may lock @mtu->lock and free qmu ring, then qmu
irq hanlder may get a NULL gpd, avoid the KE by checking gpd's value before
handling it.

e.g.
qmu done irq on cpu0 thread running on cpu1

qmu_done_tx()
handle gpd [0]
mtu3_requ_complete() mtu3_gadget_ep_disable()
unlock @mtu->lock
give back request lock @mtu->lock
mtu3_ep_disable()
mtu3_gpd_ring_free()
unlock @mtu->lock
lock @mtu->lock
get next gpd [1]

[1]: goto [0] to handle next gpd, and next gpd may be NULL.

Fixes: 48e0d3735aa5 ("usb: mtu3: supports new QMU format")
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20230417025203.18097-3-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: use boolean return value

Prefer to use boolean value due to gpd_ring_empty() return true or false.
See "16) Function return values and names" in coding-style.rst

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20230417025203.18097-2-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: give back request when rx error happens

When the Rx enconnter errors, currently, only print error logs, that
may cause class driver's RX halt, shall give back the request with
error status meanwhile.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20230417025203.18097-1-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: fix the failure of qmu stop

This happens when do stress test of uvc stream on/off which will
enable/disable endpoints. uvc has four tx requests, and may disable
endpoint between queue tx requests as following:
enable ep --> start qmu
queue tx request0
queue tx request1
queue tx request2 --> resume qmu
disable ep --> stop qmu may fail [1]
queue tx request3 --> will resume qmu, may cause qmu can't work
when enable ep next time [2]

[1]: when the tx fifo has some data to transmit, and
try to stop qmu (stop ep) meanwhile resume qmu (queue tx request),
it may cause stop qmu timeout, then can be fixed by flushing fifo
when stop qmu.
[2]: it resumes qmu again, shall stop qmu again.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reported-by: Min Guo <min.guo@mediatek.com>
Link: https://lore.kernel.org/r/20230119033322.21426-1-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: add memory barrier before set GPD's HWO

There is a seldom issue that the controller access invalid address
and trigger devapc or emimpu violation. That is due to memory access
is out of order and cause gpd data is not correct.
Add mb() to prohibit compiler or cpu from reordering to make sure GPD
is fully written before setting its HWO.

Fixes: 48e0d3735aa5 ("usb: mtu3: supports new QMU format")
Cc: stable@vger.kernel.org
Reported-by: Eddie Hung <eddie.hung@mediatek.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20211218095749.6250-2-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: add tracepoints to help debug

This patch implements a few initial tracepoints for the
mtu3 driver. More traces can be added as necessary in order
to ease the task of debugging.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: supports new QMU format

In order to support U3gen2 ISOC transfer upto 96DPs, extend
the data buffer length.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: rebuild qmu_gpd struct to prepare to support new QMU format

To support USB3 Gen2 ISOC, the data buffer length need be extended,
it's hard to make the current qmu_gpd struct compatible, so here
rebuild qmu_gpd struct and make easy to support new QMU format

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: remove unnecessary local variable @req

The local variable @req is unnecessary in qmu_tx_zlp_error_handler,
so remove it.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: fix dbginfo in qmu_tx_zlp_error_handler

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/usb/mtu3/mtu3_qmu.c: In function 'qmu_tx_zlp_error_handler':
drivers/usb/mtu3/mtu3_qmu.c:385:22: warning:
variable 'req' set but not used [-Wunused-but-set-variable]

It seems dbginfo original intention is print 'req' other than 'mreq'

Acked-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

usb: mtu3: remove QMU checksum

The QMU checksum calculation is redundant, mostly used by debug,
so remove it here.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: remove QMU checksum

The QMU checksum calculation is redundant, mostly used by debug,
so remove it here.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

USB: mtu3: Remove redundant license text

Now that the SPDX tag is in all USB files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Acked-by: Chunfeng Yun <chunfeng.yun@mediatek.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: mtu3: fix dma_addr_t printk output again

The support for 36-bit addresses originally came with an incorrect
printk format for dma addresses. Felipe changed the format string it
while applying, but the result was still incorrect, since we now have
to pass a pointer to the address instead of the integer value:

drivers/usb/mtu3/mtu3_qmu.c: In function 'mtu3_prepare_tx_gpd':
drivers/usb/mtu3/mtu3_qmu.c:261:25: error: format '%p' expects argument of type 'void *', but argument 7 has type 'dma_addr_t {aka unsigned int}' [-Werror=format=]
drivers/usb/mtu3/mtu3_qmu.c: In function 'mtu3_prepare_rx_gpd':
drivers/usb/mtu3/mtu3_qmu.c:300:25: error: format '%p' expects argument of type 'void *', but argument 7 has type 'dma_addr_t {aka unsigned int}' [-Werror=format=]

This fixes the printk argument accordingly.

Fixes: 1a46dfea0841 ("usb: mtu3: support 36-bit DMA address")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: mtu3: support 36-bit DMA address

add support for 36-bit DMA address

[ Felipe Balbi: fix printk format for dma_addr_t ]

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

usb: mtu3: declare functions static

The only user of the functions mtu3_irq() and gpd_ring_empty() are in
the same file. They can be declared as static.

Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Acked-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: Add MediaTek USB3 DRD driver

This patch adds support for the MediaTek USB3 controller
integrated into MT8173. It currently supports High-Speed
Peripheral Only mode.

Super-Speed Peripheral, Dual-Role Device and Host Only (xHCI)
modes will be added in the next patchs.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>