7528 Commits

Author SHA1 Message Date
Ilpo Järvinen
0ef5ffe116 serial: 8250_dma: Fix DMA Rx rearm race
commit 57e9af7831dcf211c5c689c2a6f209f4abdf0bce upstream.

As DMA Rx can be completed from two places, it is possible that DMA Rx
completes before DMA completion callback had a chance to complete it.
Once the previous DMA Rx has been completed, a new one can be started
on the next UART interrupt. The following race is possible
(uart_unlock_and_check_sysrq_irqrestore() replaced with
spin_unlock_irqrestore() for simplicity/clarity):

CPU0					CPU1
					dma_rx_complete()
serial8250_handle_irq()
  spin_lock_irqsave(&port->lock)
  handle_rx_dma()
    serial8250_rx_dma_flush()
      __dma_rx_complete()
        dma->rx_running = 0
        // Complete DMA Rx
  spin_unlock_irqrestore(&port->lock)

serial8250_handle_irq()
  spin_lock_irqsave(&port->lock)
  handle_rx_dma()
    serial8250_rx_dma()
      dma->rx_running = 1
      // Setup a new DMA Rx
  spin_unlock_irqrestore(&port->lock)

					  spin_lock_irqsave(&port->lock)
					  // sees dma->rx_running = 1
					  __dma_rx_complete()
					    dma->rx_running = 0
					    // Incorrectly complete
					    // running DMA Rx

This race seems somewhat theoretical to occur for real but handle it
correctly regardless. Check what is the DMA status before complething
anything in __dma_rx_complete().

Reported-by: Gilles BULOZ <gilles.buloz@kontron.com>
Tested-by: Gilles BULOZ <gilles.buloz@kontron.com>
Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine")
Cc: stable@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230130114841.25749-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09 11:26:46 +01:00
Ilpo Järvinen
e30328f599 serial: 8250_dma: Fix DMA Rx completion race
commit 31352811e13dc2313f101b890fd4b1ce760b5fe7 upstream.

__dma_rx_complete() is called from two places:
  - Through the DMA completion callback dma_rx_complete()
  - From serial8250_rx_dma_flush() after IIR_RLSI or IIR_RX_TIMEOUT
The former does not hold port's lock during __dma_rx_complete() which
allows these two to race and potentially insert the same data twice.

Extend port's lock coverage in dma_rx_complete() to prevent the race
and check if the DMA Rx is still pending completion before calling
into __dma_rx_complete().

Reported-by: Gilles BULOZ <gilles.buloz@kontron.com>
Tested-by: Gilles BULOZ <gilles.buloz@kontron.com>
Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine")
Cc: stable@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230130114841.25749-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-09 11:26:45 +01:00
George Kennedy
fc9e27f3ba vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF
[ Upstream commit 226fae124b2dac217ea5436060d623ff3385bc34 ]

After a call to console_unlock() in vcs_read() the vc_data struct can be
freed by vc_deallocate(). Because of that, the struct vc_data pointer
load must be done at the top of while loop in vcs_read() to avoid a UAF
when vcs_size() is called.

Syzkaller reported a UAF in vcs_size().

BUG: KASAN: use-after-free in vcs_size (drivers/tty/vt/vc_screen.c:215)
Read of size 4 at addr ffff8881137479a8 by task 4a005ed81e27e65/1537

CPU: 0 PID: 1537 Comm: 4a005ed81e27e65 Not tainted 6.2.0-rc5 #1
Hardware name: Red Hat KVM, BIOS 1.15.0-2.module
Call Trace:
  <TASK>
__asan_report_load4_noabort (mm/kasan/report_generic.c:350)
vcs_size (drivers/tty/vt/vc_screen.c:215)
vcs_read (drivers/tty/vt/vc_screen.c:415)
vfs_read (fs/read_write.c:468 fs/read_write.c:450)
...
  </TASK>

Allocated by task 1191:
...
kmalloc_trace (mm/slab_common.c:1069)
vc_allocate (./include/linux/slab.h:580 ./include/linux/slab.h:720
     drivers/tty/vt/vt.c:1128 drivers/tty/vt/vt.c:1108)
con_install (drivers/tty/vt/vt.c:3383)
tty_init_dev (drivers/tty/tty_io.c:1301 drivers/tty/tty_io.c:1413
     drivers/tty/tty_io.c:1390)
tty_open (drivers/tty/tty_io.c:2080 drivers/tty/tty_io.c:2126)
chrdev_open (fs/char_dev.c:415)
do_dentry_open (fs/open.c:883)
vfs_open (fs/open.c:1014)
...

Freed by task 1548:
...
kfree (mm/slab_common.c:1021)
vc_port_destruct (drivers/tty/vt/vt.c:1094)
tty_port_destructor (drivers/tty/tty_port.c:296)
tty_port_put (drivers/tty/tty_port.c:312)
vt_disallocate_all (drivers/tty/vt/vt_ioctl.c:662 (discriminator 2))
vt_ioctl (drivers/tty/vt/vt_ioctl.c:903)
tty_ioctl (drivers/tty/tty_io.c:2776)
...

The buggy address belongs to the object at ffff888113747800
  which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 424 bytes inside of
  1024-byte region [ffff888113747800, ffff888113747c00)

The buggy address belongs to the physical page:
page:00000000b3fe6c7c refcount:1 mapcount:0 mapping:0000000000000000
     index:0x0 pfn:0x113740
head:00000000b3fe6c7c order:3 compound_mapcount:0 subpages_mapcount:0
     compound_pincount:0
anon flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff)
raw: 0017ffffc0010200 ffff888100042dc0 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff888113747880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff888113747900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff888113747980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                   ^
  ffff888113747a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff888113747a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Disabling lock debugging due to kernel taint

Fixes: ac751efa6a0d ("console: rename acquire/release_console_sem() to console_lock/unlock()")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: George Kennedy <george.kennedy@oracle.com>
Link: https://lore.kernel.org/r/1674577014-12374-1-git-send-email-george.kennedy@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-09 11:26:40 +01:00
Tobias Schramm
b8d99cda52 serial: atmel: fix incorrect baudrate setup
commit 5bfdd3c654bd879bff50c2e85e42f85ae698b42f upstream.

Commit ba47f97a18f2 ("serial: core: remove baud_rates when serial console
setup") changed uart_set_options to select the correct baudrate
configuration based on the absolute error between requested baudrate and
available standard baudrate settings.
Prior to that commit the baudrate was selected based on which predefined
standard baudrate did not exceed the requested baudrate.
This change of selection logic was never reflected in the atmel serial
driver. Thus the comment left in the atmel serial driver is no longer
accurate.
Additionally the manual rounding up described in that comment and applied
via (quot - 1) requests an incorrect baudrate. Since uart_set_options uses
tty_termios_encode_baud_rate to determine the appropriate baudrate flags
this can cause baudrate selection to fail entirely because
tty_termios_encode_baud_rate will only select a baudrate if relative error
between requested and selected baudrate does not exceed +/-2%.
Fix that by requesting actual, exact baudrate used by the serial.

Fixes: ba47f97a18f2 ("serial: core: remove baud_rates when serial console setup")
Cc: stable <stable@kernel.org>
Signed-off-by: Tobias Schramm <t.schramm@manjaro.org>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Link: https://lore.kernel.org/r/20230109072940.202936-1-t.schramm@manjaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:22:47 +01:00
Lino Sanfilippo
b85498385a serial: amba-pl011: fix high priority character transmission in rs486 mode
commit 4f39aca2360c82dccd2f5179d77e94aab665bea6 upstream.

In RS485 mode the transmission of a high priority character fails since it
is written to the data register before the transmitter is enabled. Fix this
in pl011_tx_chars() by enabling RS485 transmission before writing the
character.

Fixes: 8d479237727c ("serial: amba-pl011: add RS485 support")
Cc: stable@vger.kernel.org
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20230108181735.10937-1-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:22:47 +01:00
Ilpo Järvinen
73337724cb serial: pch_uart: Pass correct sg to dma_unmap_sg()
commit e8914b52e5b024e4af3d810a935fe0805eee8a36 upstream.

A local variable sg is used to store scatterlist pointer in
pch_dma_tx_complete(). The for loop doing Tx byte accounting before
dma_unmap_sg() alters sg in its increment statement. Therefore, the
pointer passed into dma_unmap_sg() won't match to the one given to
dma_map_sg().

To fix the problem, use priv->sg_tx_p directly in dma_unmap_sg()
instead of the local variable.

Fixes: da3564ee027e ("pch_uart: add multi-scatter processing")
Cc: stable@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230103093435.4396-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:22:47 +01:00
Krzysztof Kozlowski
cb53a3366e tty: serial: qcom-geni-serial: fix slab-out-of-bounds on RX FIFO buffer
commit b8caf69a6946e18ffebad49847e258f5b6d52ac2 upstream.

Driver's probe allocates memory for RX FIFO (port->rx_fifo) based on
default RX FIFO depth, e.g. 16.  Later during serial startup the
qcom_geni_serial_port_setup() updates the RX FIFO depth
(port->rx_fifo_depth) to match real device capabilities, e.g. to 32.

The RX UART handle code will read "port->rx_fifo_depth" number of words
into "port->rx_fifo" buffer, thus exceeding the bounds.  This can be
observed in certain configurations with Qualcomm Bluetooth HCI UART
device and KASAN:

  Bluetooth: hci0: QCA Product ID   :0x00000010
  Bluetooth: hci0: QCA SOC Version  :0x400a0200
  Bluetooth: hci0: QCA ROM Version  :0x00000200
  Bluetooth: hci0: QCA Patch Version:0x00000d2b
  Bluetooth: hci0: QCA controller version 0x02000200
  Bluetooth: hci0: QCA Downloading qca/htbtfw20.tlv
  bluetooth hci0: Direct firmware load for qca/htbtfw20.tlv failed with error -2
  Bluetooth: hci0: QCA Failed to request file: qca/htbtfw20.tlv (-2)
  Bluetooth: hci0: QCA Failed to download patch (-2)
  ==================================================================
  BUG: KASAN: slab-out-of-bounds in handle_rx_uart+0xa8/0x18c
  Write of size 4 at addr ffff279347d578c0 by task swapper/0/0

  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.0-rt5-00350-gb2450b7e00be-dirty #26
  Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT)
  Call trace:
   dump_backtrace.part.0+0xe0/0xf0
   show_stack+0x18/0x40
   dump_stack_lvl+0x8c/0xb8
   print_report+0x188/0x488
   kasan_report+0xb4/0x100
   __asan_store4+0x80/0xa4
   handle_rx_uart+0xa8/0x18c
   qcom_geni_serial_handle_rx+0x84/0x9c
   qcom_geni_serial_isr+0x24c/0x760
   __handle_irq_event_percpu+0x108/0x500
   handle_irq_event+0x6c/0x110
   handle_fasteoi_irq+0x138/0x2cc
   generic_handle_domain_irq+0x48/0x64

If the RX FIFO depth changes after probe, be sure to resize the buffer.

Fixes: f9d690b6ece7 ("tty: serial: qcom_geni_serial: Allocate port->rx_fifo buffer in probe")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20221221164022.1087814-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:22:46 +01:00
Roger Pau Monne
f6003784b1 hvc/xen: lock console list traversal
[ Upstream commit c0dccad87cf68fc6012aec7567e354353097ec1a ]

The currently lockless access to the xen console list in
vtermno_to_xencons() is incorrect, as additions and removals from the
list can happen anytime, and as such the traversal of the list to get
the private console data for a given termno needs to happen with the
lock held.  Note users that modify the list already do so with the
lock taken.

Adjust current lock takers to use the _irq{save,restore} helpers,
since the context in which vtermno_to_xencons() is called can have
interrupts disabled.  Use the _irq{save,restore} set of helpers to
switch the current callers to disable interrupts in the locked region.
I haven't checked if existing users could instead use the _irq
variant, as I think it's safer to use _irq{save,restore} upfront.

While there switch from using list_for_each_entry_safe to
list_for_each_entry: the current entry cursor won't be removed as
part of the code in the loop body, so using the _safe variant is
pointless.

Fixes: 02e19f9c7cac ('hvc_xen: implement multiconsole support')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20221130163611.14686-1-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-18 11:48:54 +01:00
Rasmus Villemoes
068b512193 serial: fixup backport of "serial: Deassert Transmit Enable on probe in driver-specific way"
When 7c7f9bc986e6 ("serial: Deassert Transmit Enable on probe in
driver-specific way") got backported to 5.15.y, there known as
b079d3775237, some hunks were accidentally left out.

In fsl_lpuart.c, this amounts to uart_remove_one_port() being called
in an error path despite uart_add_one_port() not having been called.

In serial_core.c, it is possible that the omission in
uart_suspend_port() is harmless, but the backport did have the
corresponding hunk in uart_resume_port(), it runs counter to the
original commit's intention of

  Skip any invocation of ->set_mctrl() if RS485 is enabled.

and it's certainly better to be aligned with upstream.

Fixes: b079d3775237 ("serial: Deassert Transmit Enable on probe in driver-specific way")
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Dominique MARTINET <dominique.martinet@atmark-techno.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-14 10:23:28 +01:00
Yuan Can
07d547d742 serial: sunsab: Fix error handling in sunsab_init()
[ Upstream commit 1a6ec673fb627c26e2267ca0a03849f91dbd9b40 ]

The sunsab_init() returns the platform_driver_register() directly without
checking its return value, if platform_driver_register() failed, the
allocated sunsab_ports is leaked.
Fix by free sunsab_ports and set it to NULL when platform_driver_register()
failed.

Fixes: c4d37215a824 ("[SERIAL] sunsab: Convert to of_driver framework.")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Link: https://lore.kernel.org/r/20221123061212.52593-1-yuancan@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:14:28 +01:00
Gabriel Somlo
919e745fdd serial: altera_uart: fix locking in polling mode
[ Upstream commit 1307c5d33cce8a41dd77c2571e4df65a5b627feb ]

Since altera_uart_interrupt() may also be called from
a poll timer in "serving_softirq" context, use
spin_[lock_irqsave|unlock_irqrestore] variants, which
are appropriate for both softirq and hardware interrupt
contexts.

Fixes: 2f8b9c15cd88 ("altera_uart: Add support for polling mode (IRQ-less)")
Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
Link: https://lore.kernel.org/r/20221122200426.888349-1-gsomlo@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:14:28 +01:00
Jiri Slaby
e1c4f18214 tty: serial: altera_uart_{r,t}x_chars() need only uart_port
[ Upstream commit 3af44d9bb0539d5fa27d6159d696fda5f3747bff ]

Both altera_uart_{r,t}x_chars() need only uart_port, not altera_uart. So
pass the former from altera_uart_interrupt() directly.

Apart it maybe saves a dereference, this makes the transition of
altera_uart_tx_chars() easier to follow in the next patch.

Cc: Tobias Klauser <tklauser@distanz.ch>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220920052049.20507-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 1307c5d33cce ("serial: altera_uart: fix locking in polling mode")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:14:28 +01:00
Jiri Slaby
b133b45ba6 tty: serial: clean up stop-tx part in altera_uart_tx_chars()
[ Upstream commit d9c128117da41cf4cb0e80ae565b5d3ac79dffac ]

The "stop TX" path in altera_uart_tx_chars() is open-coded, so:
* use uart_circ_empty() to check if the buffer is empty, and
* when true, call altera_uart_stop_tx().

Cc: Tobias Klauser <tklauser@distanz.ch>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220920052049.20507-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 1307c5d33cce ("serial: altera_uart: fix locking in polling mode")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:14:28 +01:00
Xiongfeng Wang
6f7d82380f serial: pch: Fix PCI device refcount leak in pch_request_dma()
[ Upstream commit 8be3a7bf773700534a6e8f87f6ed2ed111254be5 ]

As comment of pci_get_slot() says, it returns a pci_device with its
refcount increased. The caller must decrement the reference count by
calling pci_dev_put().

Since 'dma_dev' is only used to filter the channel in filter(), we can
call pci_dev_put() before exiting from pch_request_dma(). Add the
missing pci_dev_put() for the normal and error path.

Fixes: 3c6a483275f4 ("Serial: EG20T: add PCH_UART driver")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Link: https://lore.kernel.org/r/20221122114559.27692-1-wangxiongfeng2@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:14:28 +01:00
Valentin Caron
0dfc7dfe5b serial: stm32: move dma_request_chan() before clk_prepare_enable()
[ Upstream commit 0d114e9ff940ebad8e88267013bf96c605a6b336 ]

If dma_request_chan() returns a PROBE_DEFER error, clk_disable_unprepare()
will be called and USART clock will be disabled. But early console can be
still active on the same USART.

While moving dma_request_chan() before clk_prepare_enable(), the clock
won't be taken in case of a DMA PROBE_DEFER error, and so it doesn't need
to be disabled. Then USART is still clocked for early console.

Fixes: a7770a4bfcf4 ("serial: stm32: defer probe for dma devices")
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20221118170602.1057863-1-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:14:28 +01:00
delisun
926b0967f7 serial: pl011: Do not clear RX FIFO & RX interrupt in unthrottle.
[ Upstream commit 032d5a71ed378ffc6a2d41a187d8488a4f9fe415 ]

Clearing the RX FIFO will cause data loss.
Copy the pl011_enabl_interrupts implementation, and remove the clear
interrupt and FIFO part of the code.

Fixes: 211565b10099 ("serial: pl011: UPSTAT_AUTORTS requires .throttle/unthrottle")
Signed-off-by: delisun <delisun@pateo.com.cn>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20221110020108.7700-1-delisun@pateo.com.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:14:28 +01:00
Jiamei Xie
d71a611fca serial: amba-pl011: avoid SBSA UART accessing DMACR register
[ Upstream commit 94cdb9f33698478b0e7062586633c42c6158a786 ]

Chapter "B Generic UART" in "ARM Server Base System Architecture" [1]
documentation describes a generic UART interface. Such generic UART
does not support DMA. In current code, sbsa_uart_pops and
amba_pl011_pops share the same stop_rx operation, which will invoke
pl011_dma_rx_stop, leading to an access of the DMACR register. This
commit adds a using_rx_dma check in pl011_dma_rx_stop to avoid the
access to DMACR register for SBSA UARTs which does not support DMA.

When the kernel enables DMA engine with "CONFIG_DMA_ENGINE=y", Linux
SBSA PL011 driver will access PL011 DMACR register in some functions.
For most real SBSA Pl011 hardware implementations, the DMACR write
behaviour will be ignored. So these DMACR operations will not cause
obvious problems. But for some virtual SBSA PL011 hardware, like Xen
virtual SBSA PL011 (vpl011) device, the behaviour might be different.
Xen vpl011 emulation will inject a data abort to guest, when guest is
accessing an unimplemented UART register. As Xen VPL011 is SBSA
compatible, it will not implement DMACR register. So when Linux SBSA
PL011 driver access DMACR register, it will get an unhandled data abort
fault and the application will get a segmentation fault:
Unhandled fault at 0xffffffc00944d048
Mem abort info:
  ESR = 0x96000000
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x00: ttbr address size fault
Data abort info:
  ISV = 0, ISS = 0x00000000
  CM = 0, WnR = 0
swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000020e2e000
[ffffffc00944d048] pgd=100000003ffff803, p4d=100000003ffff803, pud=100000003ffff803, pmd=100000003fffa803, pte=006800009c090f13
Internal error: ttbr address size fault: 96000000 [#1] PREEMPT SMP
...
Call trace:
 pl011_stop_rx+0x70/0x80
 tty_port_shutdown+0x7c/0xb4
 tty_port_close+0x60/0xcc
 uart_close+0x34/0x8c
 tty_release+0x144/0x4c0
 __fput+0x78/0x220
 ____fput+0x1c/0x30
 task_work_run+0x88/0xc0
 do_notify_resume+0x8d0/0x123c
 el0_svc+0xa8/0xc0
 el0t_64_sync_handler+0xa4/0x130
 el0t_64_sync+0x1a0/0x1a4
Code: b9000083 b901f001 794038a0 8b000042 (b9000041)
---[ end trace 83dd93df15c3216f ]---
note: bootlogd[132] exited with preempt_count 1
/etc/rcS.d/S07bootlogd: line 47: 132 Segmentation fault start-stop-daemon

This has been discussed in the Xen community, and we think it should fix
this in Linux. See [2] for more information.

[1] https://developer.arm.com/documentation/den0094/c/?lang=en
[2] https://lists.xenproject.org/archives/html/xen-devel/2022-11/msg00543.html

Fixes: 0dd1e247fd39 (drivers: PL011: add support for the ARM SBSA generic UART)
Signed-off-by: Jiamei Xie <jiamei.xie@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20221117103237.86856-1-jiamei.xie@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:14:28 +01:00
Yuan Can
f76824ab2b serial: 8250_bcm7271: Fix error handling in brcmuart_init()
[ Upstream commit 6a3ff858915fa8ca36c7eb02c87c9181ae2fc333 ]

A problem about 8250_bcm7271 create debugfs failed is triggered with the
following log given:

 [  324.516635] debugfs: Directory 'bcm7271-uart' with parent '/' already present!

The reason is that brcmuart_init() returns platform_driver_register()
directly without checking its return value, if platform_driver_register()
failed, it returns without destroy the newly created debugfs, resulting
the debugfs of 8250_bcm7271 can never be created later.

 brcmuart_init()
   debugfs_create_dir() # create debugfs directory
   platform_driver_register()
     driver_register()
       bus_add_driver()
         priv = kzalloc(...) # OOM happened
   # return without destroy debugfs directory

Fix by removing debugfs when platform_driver_register() returns error.

Fixes: 41a469482de2 ("serial: 8250: Add new 8250-core based Broadcom STB driver")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Link: https://lore.kernel.org/r/20221109072110.117291-2-yuancan@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:14:27 +01:00
Kartik
6b4424efcf serial: tegra: Read DMA status before terminating
[ Upstream commit 109a951a9f1fd8a34ebd1896cbbd5d5cede880a7 ]

Read the DMA status before terminating the DMA, as doing so deletes
the DMA desc.

Also, to get the correct transfer status information, pause the DMA
using dmaengine_pause() before reading the DMA status.

Fixes: e9ea096dd225 ("serial: tegra: add serial driver")
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Signed-off-by: Kartik <kkartik@nvidia.com>
Link: https://lore.kernel.org/r/1666105086-17326-1-git-send-email-kkartik@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:14:27 +01:00
Lukas Wunner
db3f8da033 serial: stm32: Deassert Transmit Enable on ->rs485_config()
[ Upstream commit adafbbf6895eb0ce41a313c6ee68870ab9aa93cd ]

The STM32 USART can control RS-485 Transmit Enable in hardware.  Since
commit 7df5081cbf5e ("serial: stm32: Add RS485 RTS GPIO control"),
it can alternatively be controlled in software.  That was done to allow
RS-485 even if the RTS pin is unavailable because it's pinmuxed to a
different function.

However the commit neglected to deassert Transmit Enable upon invocation
of the ->rs485_config() callback.  Fix it.

Avoid forward declarations by moving stm32_usart_tx_empty(),
stm32_usart_rs485_rts_enable() and stm32_usart_rs485_rts_disable()
further up in the driver.

Fixes: 7df5081cbf5e ("serial: stm32: Add RS485 RTS GPIO control")
Cc: stable@vger.kernel.org # v5.9+
Cc: Marek Vasut <marex@denx.de>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/6059eab35dba394468335ef640df8b0050fd9dbd.1662886616.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-08 11:28:45 +01:00
Marek Vasut
45f628f4fd serial: stm32: Use TC interrupt to deassert GPIO RTS in RS485 mode
[ Upstream commit d7c76716169ddc37cf6316ff381d34ea807fbfd7 ]

In case the RS485 mode is emulated using GPIO RTS, use the TC interrupt
to deassert the GPIO RTS, otherwise the GPIO RTS stays asserted after a
transmission ended and the RS485 cannot work.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Erwan Le Ray <erwan.leray@foss.st.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jean Philippe Romain <jean-philippe.romain@foss.st.com>
Cc: Valentin Caron <valentin.caron@foss.st.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-serial@vger.kernel.org
Link: https://lore.kernel.org/r/20220430162845.244655-2-marex@denx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-08 11:28:45 +01:00
Marek Vasut
c60eae5b1d serial: stm32: Factor out GPIO RTS toggling into separate function
[ Upstream commit 3bcea529b295a993b1b05db63f245ae8030c5acf ]

Pull out the GPIO RTS enable and disable handling into separate function.
Limit the scope of GPIO RTS toggling only to GPIO emulated RS485 too.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Erwan Le Ray <erwan.leray@foss.st.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jean Philippe Romain <jean-philippe.romain@foss.st.com>
Cc: Valentin Caron <valentin.caron@foss.st.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-serial@vger.kernel.org
Link: https://lore.kernel.org/r/20220430162845.244655-1-marex@denx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-08 11:28:45 +01:00
Lukas Wunner
e2223f5fbb serial: 8250: 8250_omap: Avoid RS485 RTS glitch on ->set_termios()
[ Upstream commit 038ee49fef18710bedd38b531d173ccd746b2d8d ]

RS485-enabled UART ports on TI Sitara SoCs with active-low polarity
exhibit a Transmit Enable glitch on ->set_termios():

omap8250_restore_regs(), which is called from omap_8250_set_termios(),
sets the TCRTLR bit in the MCR register and clears all other bits,
including RTS.  If RTS uses active-low polarity, it is now asserted
for no reason.

The TCRTLR bit is subsequently cleared by writing up->mcr to the MCR
register.  That variable is always zero, so the RTS bit is still cleared
(incorrectly so if RTS is active-high).

(up->mcr is not, as one might think, a cache of the MCR register's
current value.  Rather, it only caches a single bit of that register,
the AFE bit.  And it only does so if the UART supports the AFE bit,
which OMAP does not.  For details see serial8250_do_set_termios() and
serial8250_do_set_mctrl().)

Finally at the end of omap8250_restore_regs(), the MCR register is
restored (and RTS deasserted) by a call to up->port.ops->set_mctrl()
(which equals serial8250_set_mctrl()) and serial8250_em485_stop_tx().

So there's an RTS glitch between setting TCRTLR and calling
serial8250_em485_stop_tx().  Avoid by using a read-modify-write
when setting TCRTLR.

While at it, drop a redundant initialization of up->mcr.  As explained
above, the variable isn't used by the driver and it is already
initialized to zero because it is part of the static struct
serial8250_ports[] declared in 8250_core.c.  (Static structs are
initialized to zero per section 6.7.8 nr. 10 of the C99 standard.)

Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Su Bao Cheng <baocheng.su@siemens.com>
Tested-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/6554b0241a2c7fd50f32576fdbafed96709e11e8.1664278942.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-02 17:41:10 +01:00
Sherry Sun
e8915faa9f tty: serial: fsl_lpuart: don't break the on-going transfer when global reset
[ Upstream commit 76bad3f88750f8cc465c489e6846249e0bc3d8f5 ]

lpuart_global_reset() shouldn't break the on-going transmit engine, need
to recover the on-going data transfer after reset.

This can help earlycon here, since commit 60f361722ad2 ("serial:
fsl_lpuart: Reset prior to registration") moved lpuart_global_reset()
before uart_add_one_port(), earlycon is writing during global reset,
as global reset will disable the TX and clear the baud rate register,
which caused the earlycon cannot work any more after reset, needs to
restore the baud rate and re-enable the transmitter to recover the
earlycon write.

Also move the lpuart_global_reset() down, then we can reuse the
lpuart32_tx_empty() without declaration.

Fixes: bd5305dcabbc ("tty: serial: fsl_lpuart: do software reset for imx7ulp and imx8qxp")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221024085844.22786-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-02 17:40:59 +01:00
Ilpo Järvinen
bd19013935 serial: fsl_lpuart: Fill in rs485_supported
[ Upstream commit 07481f448b635d7cebb92d5940f5bea5c4395a26 ]

Add information on supported serial_rs485 features.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-16-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 76bad3f88750 ("tty: serial: fsl_lpuart: don't break the on-going transfer when global reset")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-02 17:40:59 +01:00
Ilpo Järvinen
87c81c19cd serial: Add rs485_supported to uart_port
[ Upstream commit 8925c31c1ac2f1e05da988581f2a70a2a8c4d638 ]

Preparing to move serial_rs485 struct sanitization into serial core,
each driver has to provide what fields/flags it supports. This
information is pointed into by rs485_supported.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 76bad3f88750 ("tty: serial: fsl_lpuart: don't break the on-going transfer when global reset")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-02 17:40:59 +01:00
Ilpo Järvinen
2ac6276864 serial: 8250_lpss: Use 16B DMA burst with Elkhart Lake
commit 7090abd6ad0610a144523ce4ffcb8560909bf2a8 upstream.

Configure DMA to use 16B burst size with Elkhart Lake. This makes the
bus use more efficient and works around an issue which occurs with the
previously used 1B.

The fix was initially developed by Srikanth Thokala and Aman Kumar.
This together with the previous config change is the cleaned up version
of the original fix.

Fixes: 0a9410b981e9 ("serial: 8250_lpss: Enable DMA on Intel Elkhart Lake")
Cc: <stable@vger.kernel.org> # serial: 8250_lpss: Configure DMA also w/o DMA filter
Reported-by: Wentong Wu <wentong.wu@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221108121952.5497-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-26 09:24:49 +01:00
Ilpo Järvinen
0cafb719be serial: 8250_lpss: Configure DMA also w/o DMA filter
commit 1bfcbe5805d0cfc83c3544dcd01e0a282c1f6790 upstream.

If the platform doesn't use DMA device filter (as is the case with
Elkhart Lake), whole lpss8250_dma_setup() setup is skipped. This
results in skipping also *_maxburst setup which is undesirable.
Refactor lpss8250_dma_setup() to configure DMA even if filter is not
setup.

Cc: stable <stable@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221108121952.5497-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-26 09:24:47 +01:00
Ilpo Järvinen
59f6596697 serial: 8250: Flush DMA Rx on RLSI
commit 1980860e0c8299316cddaf0992dd9e1258ec9d88 upstream.

Returning true from handle_rx_dma() without flushing DMA first creates
a data ordering hazard. If DMA Rx has handled any character at the
point when RLSI occurs, the non-DMA path handles any pending characters
jumping them ahead of those characters that are pending under DMA.

Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221108121952.5497-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-26 09:24:47 +01:00
Ilpo Järvinen
118b52c2ae serial: 8250: Fall back to non-DMA Rx if IIR_RDI occurs
commit a931237cbea256aff13bb403da13a97b2d1605d9 upstream.

DW UART sometimes triggers IIR_RDI during DMA Rx when IIR_RX_TIMEOUT
should have been triggered instead. Since IIR_RDI has higher priority
than IIR_RX_TIMEOUT, this causes the Rx to hang into interrupt loop.
The problem seems to occur at least with some combinations of
small-sized transfers (I've reproduced the problem on Elkhart Lake PSE
UARTs).

If there's already an on-going Rx DMA and IIR_RDI triggers, fall
graciously back to non-DMA Rx. That is, behave as if IIR_RX_TIMEOUT had
occurred.

8250_omap already considers IIR_RDI similar to this change so its
nothing unheard of.

Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling")
Cc: <stable@vger.kernel.org>
Co-developed-by: Srikanth Thokala <srikanth.thokala@intel.com>
Signed-off-by: Srikanth Thokala <srikanth.thokala@intel.com>
Co-developed-by: Aman Kumar <aman.kumar@intel.com>
Signed-off-by: Aman Kumar <aman.kumar@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221108121952.5497-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-26 09:24:46 +01:00
Duoming Zhou
33cabe04d2 tty: n_gsm: fix sleep-in-atomic-context bug in gsm_control_send
[ Upstream commit 7b7dfe4833c70a11cdfa51b38705103bd31eddaa ]

The function gsm_dlci_t1() is a timer handler that runs in an
atomic context, but it calls "kzalloc(..., GFP_KERNEL)" that
may sleep. As a result, the sleep-in-atomic-context bug will
happen. The process is shown below:

gsm_dlci_t1()
 gsm_dlci_open()
  gsm_modem_update()
   gsm_modem_upd_via_msc()
    gsm_control_send()
     kzalloc(sizeof(.., GFP_KERNEL) //may sleep

This patch changes the gfp_t parameter of kzalloc() from GFP_KERNEL to
GFP_ATOMIC in order to mitigate the bug.

Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20221002040709.27849-1-duoming@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-26 09:24:35 +01:00
Shawn Guo
ae22294e21 serial: imx: Add missing .thaw_noirq hook
[ Upstream commit 4561d8008a467cb05ac632a215391d6b787f40aa ]

The following warning is seen with non-console UART instance when
system hibernates.

[   37.371969] ------------[ cut here ]------------
[   37.376599] uart3_root_clk already disabled
[   37.380810] WARNING: CPU: 0 PID: 296 at drivers/clk/clk.c:952 clk_core_disable+0xa4/0xb0
...
[   37.506986] Call trace:
[   37.509432]  clk_core_disable+0xa4/0xb0
[   37.513270]  clk_disable+0x34/0x50
[   37.516672]  imx_uart_thaw+0x38/0x5c
[   37.520250]  platform_pm_thaw+0x30/0x6c
[   37.524089]  dpm_run_callback.constprop.0+0x3c/0xd4
[   37.528972]  device_resume+0x7c/0x160
[   37.532633]  dpm_resume+0xe8/0x230
[   37.536036]  hibernation_snapshot+0x288/0x430
[   37.540397]  hibernate+0x10c/0x2e0
[   37.543798]  state_store+0xc4/0xd0
[   37.547203]  kobj_attr_store+0x1c/0x30
[   37.550953]  sysfs_kf_write+0x48/0x60
[   37.554619]  kernfs_fop_write_iter+0x118/0x1ac
[   37.559063]  new_sync_write+0xe8/0x184
[   37.562812]  vfs_write+0x230/0x290
[   37.566214]  ksys_write+0x68/0xf4
[   37.569529]  __arm64_sys_write+0x20/0x2c
[   37.573452]  invoke_syscall.constprop.0+0x50/0xf0
[   37.578156]  do_el0_svc+0x11c/0x150
[   37.581648]  el0_svc+0x30/0x140
[   37.584792]  el0t_64_sync_handler+0xe8/0xf0
[   37.588976]  el0t_64_sync+0x1a0/0x1a4
[   37.592639] ---[ end trace 56e22eec54676d75 ]---

On hibernating, pm core calls into related hooks in sequence like:

    .freeze
    .freeze_noirq
    .thaw_noirq
    .thaw

With .thaw_noirq hook being absent, the clock will be disabled in a
unbalanced call which results the warning above.

    imx_uart_freeze()
        clk_prepare_enable()
    imx_uart_suspend_noirq()
        clk_disable()
    imx_uart_thaw
        clk_disable_unprepare()

Adding the missing .thaw_noirq hook as imx_uart_resume_noirq() will have
the call sequence corrected as below and thus fix the warning.

    imx_uart_freeze()
        clk_prepare_enable()
    imx_uart_suspend_noirq()
        clk_disable()
    imx_uart_resume_noirq()
        clk_enable()
    imx_uart_thaw
        clk_disable_unprepare()

Fixes: 09df0b3464e5 ("serial: imx: fix endless loop during suspend")
Reviewed-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Link: https://lore.kernel.org/r/20221012121353.2346280-1-shawn.guo@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-26 09:24:35 +01:00
Tony Lindgren
26db1cd519 serial: 8250: omap: Flush PM QOS work on remove
[ Upstream commit d0b68629bd2fb61e0171a62f2e8da3db322f5cf6 ]

Rebinding 8250_omap in a loop will at some point produce a warning for
kernel/power/qos.c:296 cpu_latency_qos_update_request() with error
"cpu_latency_qos_update_request called for unknown object". Let's flush
the possibly pending PM QOS work scheduled from omap8250_runtime_suspend()
before we disable runtime PM.

Fixes: 61929cf0169d ("tty: serial: Add 8250-core based omap driver")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20221028110044.54719-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-26 09:24:35 +01:00
Tony Lindgren
e0db709a58 serial: 8250: omap: Fix unpaired pm_runtime_put_sync() in omap8250_remove()
[ Upstream commit e3f0c638f428fd66b5871154b62706772045f91a ]

On remove, we get an error for "Runtime PM usage count underflow!". I guess
this driver is mostly built-in, and this issue has gone unnoticed for a
while. Somehow I did not catch this issue with my earlier fix done with
commit 4e0f5cc65098 ("serial: 8250_omap: Fix probe and remove for PM
runtime").

Fixes: 4e0f5cc65098 ("serial: 8250_omap: Fix probe and remove for PM runtime")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Depends-on: dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
Link: https://lore.kernel.org/r/20221028105813.54290-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-26 09:24:34 +01:00
Matthias Schiffer
83b6d4d6da serial: 8250_omap: remove wait loop from Errata i202 workaround
[ Upstream commit e828e56684d61b17317e0cfdef83791fa61cb76b ]

We were occasionally seeing the "Errata i202: timedout" on an AM335x
board when repeatedly opening and closing a UART connected to an active
sender. As new input may arrive at any time, it is possible to miss the
"RX FIFO empty" condition, forcing the loop to wait until it times out.

Nothing in the i202 Advisory states that such a wait is even necessary;
other FIFO clear functions like serial8250_clear_fifos() do not wait
either. For this reason, it seems safe to remove the wait, fixing the
mentioned issue.

Fixes: 61929cf0169d ("tty: serial: Add 8250-core based omap driver")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Link: https://lore.kernel.org/r/20221013112339.2540767-1-matthias.schiffer@ew.tq-group.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-26 09:24:34 +01:00
Tony Lindgren
76db05ab70 serial: 8250: omap: Fix missing PM runtime calls for omap8250_set_mctrl()
[ Upstream commit 93810191f5d23652c0b8a1a9b3a4a89d6fd5063e ]

There are cases where omap8250_set_mctrl() may get called after the
UART has already autoidled causing an asynchronous external abort.

This can happen on ttyport_open():

mem_serial_in from omap8250_set_mctrl+0x38/0xa0
omap8250_set_mctrl from uart_update_mctrl+0x4c/0x58
uart_update_mctrl from uart_dtr_rts+0x60/0xa8
uart_dtr_rts from tty_port_block_til_ready+0xd0/0x2a8
tty_port_block_til_ready from uart_open+0x14/0x1c
uart_open from ttyport_open+0x64/0x148

And on ttyport_close():

omap8250_set_mctrl from uart_update_mctrl+0x3c/0x48
uart_update_mctrl from uart_dtr_rts+0x54/0x9c
uart_dtr_rts from tty_port_shutdown+0x78/0x9c
tty_port_shutdown from tty_port_close+0x3c/0x74
tty_port_close from ttyport_close+0x40/0x58

It can also happen on disassociate_ctty() calling uart_shutdown()
that ends up calling omap8250_set_mctrl().

Let's fix the issue by adding missing PM runtime calls to
omap8250_set_mctrl(). To do this, we need to add __omap8250_set_mctrl()
that can be called from both omap8250_set_mctrl(), and from runtime PM
resume path when restoring the registers.

Fixes: 61929cf0169d ("tty: serial: Add 8250-core based omap driver")
Reported-by: Merlijn Wajer <merlijn@wizzup.org>
Reported-by: Romain Naour <romain.naour@smile.fr>
Reported-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Tested-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Depends-on: dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
Link: https://lore.kernel.org/r/20221024063613.25943-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-26 09:24:34 +01:00
Helge Deller
5daf985dd0 parisc: Make 8250_gsc driver dependend on CONFIG_PARISC
commit e8a18e3f00f3ee8d07c17ab1ea3ad4df4a3b6fe0 upstream.

Although the name of the driver 8250_gsc.c suggests that it handles
only serial ports on the GSC bus, it does handle serial ports listed
in the parisc machine inventory as well, e.g. the serial ports in a
C8000 PCI-only workstation.

Change the dependency to CONFIG_PARISC, so that the driver gets included
in the kernel even if CONFIG_GSC isn't set.

Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-10 18:15:40 +01:00
Lukas Wunner
0c9c1306d6 serial: ar933x: Deassert Transmit Enable on ->rs485_config()
commit 3a939433ddc1bab98be028903aaa286e5e7461d7 upstream.

The ar933x_uart driver neglects to deassert Transmit Enable when
->rs485_config() is invoked.  Fix it.

Fixes: 9be1064fe524 ("serial: ar933x_uart: add RS485 support")
Cc: stable@vger.kernel.org # v5.7+
Cc: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Ilpo JÀrvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-10 18:15:24 +01:00
Lukas Wunner
b079d37752 serial: Deassert Transmit Enable on probe in driver-specific way
commit 7c7f9bc986e698873b489c371a08f206979d06b7 upstream.

When a UART port is newly registered, uart_configure_port() seeks to
deassert RS485 Transmit Enable by setting the RTS bit in port->mctrl.
However a number of UART drivers interpret a set RTS bit as *assertion*
instead of deassertion:  Affected drivers include those using
serial8250_em485_config() (except 8250_bcm2835aux.c) and some using
mctrl_gpio (e.g. imx.c).

Since the interpretation of the RTS bit is driver-specific, it is not
suitable as a means to centrally deassert Transmit Enable in the serial
core.  Instead, the serial core must call on drivers to deassert it in
their driver-specific way.  One way to achieve that is to call
->rs485_config().  It implicitly deasserts Transmit Enable.

So amend uart_configure_port() and uart_resume_port() to invoke
uart_rs485_config().  That allows removing calls to uart_rs485_config()
from drivers' ->probe() hooks and declaring the function static.

Skip any invocation of ->set_mctrl() if RS485 is enabled.  RS485 has no
hardware flow control, so the modem control lines are irrelevant and
need not be touched.  When leaving RS485 mode, reset the modem control
lines to the state stored in port->mctrl.  That way, UARTs which are
muxed between RS485 and RS232 transceivers drive the lines correctly
when switched to RS232.  (serial8250_do_startup() historically raises
the OUT1 modem signal because otherwise interrupts are not signaled on
ancient PC UARTs, but I believe that no longer applies to modern,
RS485-capable UARTs and is thus safe to be skipped.)

imx.c modifies port->mctrl whenever Transmit Enable is asserted and
deasserted.  Stop it from doing that so port->mctrl reflects the RS232
line state.

8250_omap.c deasserts Transmit Enable on ->runtime_resume() by calling
->set_mctrl().  Because that is now a no-op in RS485 mode, amend the
function to call serial8250_em485_stop_tx().

fsl_lpuart.c retrieves and applies the RS485 device tree properties
after registering the UART port.  Because applying now happens on
registration in uart_configure_port(), move retrieval of the properties
ahead of uart_add_one_port().

Link: https://lore.kernel.org/all/20220329085050.311408-1-matthias.schiffer@ew.tq-group.com/
Link: https://lore.kernel.org/all/8f538a8903795f22f9acc94a9a31b03c9c4ccacb.camel@ginzinger.com/
Fixes: d3b3404df318 ("serial: Fix incorrect rs485 polarity on uart open")
Cc: stable@vger.kernel.org # v4.14+
Reported-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reported-by: Roosen Henri <Henri.Roosen@ginzinger.com>
Tested-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/2de36eba3fbe11278d5002e4e501afe0ceaca039.1663863805.git.lukas@wunner.de
Signed-off-by: Daisuke Mizobuchi <mizo@atmark-techno.com>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-03 23:59:20 +09:00
Lino Sanfilippo
63f75fea3a serial: core: move RS485 configuration tasks from drivers into core
commit 0ed12afa5655512ee418047fb3546d229df20aa1 upstream.

Several drivers that support setting the RS485 configuration via userspace
implement one or more of the following tasks:

- in case of an invalid RTS configuration (both RTS after send and RTS on
  send set or both unset) fall back to enable RTS on send and disable RTS
  after send

- nullify the padding field of the returned serial_rs485 struct

- copy the configuration into the uart port struct

- limit RTS delays to 100 ms

Move these tasks into the serial core to make them generic and to provide
a consistent behaviour among all drivers.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Link: https://lore.kernel.org/r/20220410104642.32195-2-LinoSanfilippo@gmx.de
Signed-off-by: Daisuke Mizobuchi <mizo@atmark-techno.com>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-03 23:59:20 +09:00
Pali Rohár
6a54f76974 serial: 8250: Fix restoring termios speed after suspend
[ Upstream commit 379a33786d489ab81885ff0b3935cfeb36137fea ]

Since commit edc6afc54968 ("tty: switch to ktermios and new framework")
termios speed is no longer stored only in c_cflag member but also in new
additional c_ispeed and c_ospeed members. If BOTHER flag is set in c_cflag
then termios speed is stored only in these new members.

Since commit 027b57170bf8 ("serial: core: Fix initializing and restoring
termios speed") termios speed is available also in struct console.

So properly restore also c_ispeed and c_ospeed members after suspend to fix
restoring termios speed which is not represented by Bnnn constant.

Fixes: 4516d50aabed ("serial: 8250: Use canary to restart console after suspend")
Signed-off-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/20220924104324.4035-1-pali@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-10-26 12:35:15 +02:00
Sherry Sun
c4293def88 tty: serial: fsl_lpuart: disable dma rx/tx use flags in lpuart_dma_shutdown
[ Upstream commit 316ae95c175a7d770d1bfe4c011192712f57aa4a ]

lpuart_dma_shutdown tears down lpuart dma, but lpuart_flush_buffer can
still occur which in turn tries to access dma apis if lpuart_dma_tx_use
flag is true. At this point since dma is torn down, these dma apis can
abort. Set lpuart_dma_tx_use and the corresponding rx flag
lpuart_dma_rx_use to false in lpuart_dma_shutdown so that dmas are not
accessed after they are relinquished.

Otherwise, when try to kill btattach, kernel may panic. This patch may
fix this issue.
root@imx8ulpevk:~# btattach -B /dev/ttyLP2 -S 115200
^C[   90.182296] Internal error: synchronous external abort: 96000210 [#1] PREEMPT SMP
[   90.189806] Modules linked in: moal(O) mlan(O)
[   90.194258] CPU: 0 PID: 503 Comm: btattach Tainted: G           O      5.15.32-06136-g34eecdf2f9e4 #37
[   90.203554] Hardware name: NXP i.MX8ULP 9X9 EVK (DT)
[   90.208513] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[   90.215470] pc : fsl_edma3_disable_request+0x8/0x60
[   90.220358] lr : fsl_edma3_terminate_all+0x34/0x20c
[   90.225237] sp : ffff800013f0bac0
[   90.228548] x29: ffff800013f0bac0 x28: 0000000000000001 x27: ffff000008404800
[   90.235681] x26: ffff000008404960 x25: ffff000008404a08 x24: ffff000008404a00
[   90.242813] x23: ffff000008404a60 x22: 0000000000000002 x21: 0000000000000000
[   90.249946] x20: ffff800013f0baf8 x19: ffff00000559c800 x18: 0000000000000000
[   90.257078] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[   90.264211] x14: 0000000000000003 x13: 0000000000000000 x12: 0000000000000040
[   90.271344] x11: ffff00000600c248 x10: ffff800013f0bb10 x9 : ffff000057bcb090
[   90.278477] x8 : fffffc0000241a08 x7 : ffff00000534ee00 x6 : ffff000008404804
[   90.285609] x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff0000055b3480
[   90.292742] x2 : ffff8000135c0000 x1 : ffff00000534ee00 x0 : ffff00000559c800
[   90.299876] Call trace:
[   90.302321]  fsl_edma3_disable_request+0x8/0x60
[   90.306851]  lpuart_flush_buffer+0x40/0x160
[   90.311037]  uart_flush_buffer+0x88/0x120
[   90.315050]  tty_driver_flush_buffer+0x20/0x30
[   90.319496]  hci_uart_flush+0x44/0x90
[   90.323162]  +0x34/0x12c
[   90.327253]  tty_ldisc_close+0x38/0x70
[   90.331005]  tty_ldisc_release+0xa8/0x190
[   90.335018]  tty_release_struct+0x24/0x8c
[   90.339022]  tty_release+0x3ec/0x4c0
[   90.342593]  __fput+0x70/0x234
[   90.345652]  ____fput+0x14/0x20
[   90.348790]  task_work_run+0x84/0x17c
[   90.352455]  do_exit+0x310/0x96c
[   90.355688]  do_group_exit+0x3c/0xa0
[   90.359259]  __arm64_sys_exit_group+0x1c/0x20
[   90.363609]  invoke_syscall+0x48/0x114
[   90.367362]  el0_svc_common.constprop.0+0xd4/0xfc
[   90.372068]  do_el0_svc+0x2c/0x94
[   90.375379]  el0_svc+0x28/0x80
[   90.378438]  el0t_64_sync_handler+0xa8/0x130
[   90.382711]  el0t_64_sync+0x1a0/0x1a4
[   90.386376] Code: 17ffffda d503201f d503233f f9409802 (b9400041)
[   90.392467] ---[ end trace 2f60524b4a43f1f6 ]---
[   90.397073] note: btattach[503] exited with preempt_count 1
[   90.402636] Fixing recursive fault but reboot is needed!

Fixes: 6250cc30c4c4 ("tty: serial: fsl_lpuart: Use scatter/gather DMA for Tx")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Thara Gopinath <tgopinath@microsoft.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20220920111703.1532-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-10-26 12:35:14 +02:00
Ilpo Järvinen
a91a3c2d8d serial: 8250: Toggle IER bits on only after irq has been set up
[ Upstream commit 039d4926379b1d1c17b51cf21c500a5eed86899e ]

Invoking TIOCVHANGUP on 8250_mid port on Ice Lake-D and then reopening
the port triggers these faults during serial8250_do_startup():

  DMAR: DRHD: handling fault status reg 3
  DMAR: [DMA Write NO_PASID] Request device [00:1a.0] fault addr 0x0 [fault reason 0x05] PTE Write access is not set

If the IRQ hasn't been set up yet, the UART will have zeroes in its MSI
address/data registers. Disabling the IRQ at the interrupt controller
won't stop the UART from performing a DMA write to the address programmed
in its MSI address register (zero) when it wants to signal an interrupt.

The UARTs (in Ice Lake-D) implement PCI 2.1 style MSI without masking
capability, so there is no way to mask the interrupt at the source PCI
function level, except disabling the MSI capability entirely, but that
would cause it to fall back to INTx# assertion, and the PCI specification
prohibits disabling the MSI capability as a way to mask a function's
interrupt service request.

The MSI address register is zeroed by the hangup as the irq is freed.
The interrupt is signalled during serial8250_do_startup() performing a
THRE test that temporarily toggles THRI in IER. The THRE test currently
occurs before UART's irq (and MSI address) is properly set up.

Refactor serial8250_do_startup() such that irq is set up before the
THRE test. The current irq setup code is intermixed with the timer
setup code. As THRE test must be performed prior to the timer setup,
extract it into own function and call it only after the THRE test.

The ->setup_timer() needs to be part of the struct uart_8250_ops in
order to not create circular dependency between 8250 and 8250_base
modules.

Fixes: 40b36daad0ac ("[PATCH] 8250 UART backup timer")
Reported-by: Lennert Buytenhek <buytenh@arista.com>
Tested-by: Lennert Buytenhek <buytenh@arista.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220922070005.2965-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-10-26 12:35:14 +02:00
Dan Carpenter
6be8e565a4 drivers: serial: jsm: fix some leaks in probe
[ Upstream commit 1d5859ef229e381f4db38dce8ed58e4bf862006b ]

This error path needs to unwind instead of just returning directly.

Fixes: 03a8482c17dd ("drivers: serial: jsm: Enable support for Digi Classic adapters")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YyxFh1+lOeZ9WfKO@kili
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-10-26 12:35:13 +02:00
Shubhrajyoti Datta
aeffca4344 tty: xilinx_uartps: Fix the ignore_status
[ Upstream commit b8a6c3b3d4654fba19881cc77da61eac29f57cae ]

Currently the ignore_status is not considered in the isr.
Add a check to add the ignore_status.

Fixes: 61ec9016988f ("tty/serial: add support for Xilinx PS UART")
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Link: https://lore.kernel.org/r/20220729114748.18332-5-shubhrajyoti.datta@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-10-26 12:35:05 +02:00
Maciej W. Rozycki
209a94c519 serial: 8250: Request full 16550A feature probing for OxSemi PCIe devices
commit 00b7a4d4ee42be1c515e56cb1e8ba0f25e271d8e upstream.

Oxford Semiconductor PCIe (Tornado) 950 serial port devices need to
operate in the enhanced mode via the EFR register for the Divide-by-M
N/8 baud rate generator prescaler to be used in their native UART mode.
Otherwise the prescaler is fixed at 1 causing grossly incorrect baud
rates to be programmed.

Accessing the EFR register requires 16550A features to have been probed
for, so request this to happen regardless of SERIAL_8250_16550A_VARIANTS
by setting UPF_FULL_PROBE in port flags.

Fixes: 366f6c955d4d ("serial: 8250: Add proper clock handling for OxSemi PCIe devices")
Cc: stable@vger.kernel.org # v5.19+
Reported-by: Anders Blomdell <anders.blomdell@control.lth.se>
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2209210005040.41633@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-10-26 12:34:25 +02:00
Maciej W. Rozycki
63a3d75cf1 serial: 8250: Let drivers request full 16550A feature probing
commit 9906890c89e4dbd900ed87ad3040080339a7f411 upstream.

A SERIAL_8250_16550A_VARIANTS configuration option has been recently
defined that lets one request the 8250 driver not to probe for 16550A
device features so as to reduce the driver's device startup time in
virtual machines.

Some actual hardware devices require these features to have been fully
determined however for their driver to work correctly, so define a flag
to let drivers request full 16550A feature probing on a device-by-device
basis if required regardless of the SERIAL_8250_16550A_VARIANTS option
setting chosen.

Fixes: dc56ecb81a0a ("serial: 8250: Support disabling mdelay-filled probes of 16550A variants")
Cc: stable@vger.kernel.org # v5.6+
Reported-by: Anders Blomdell <anders.blomdell@control.lth.se>
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2209202357520.41633@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-10-26 12:34:24 +02:00
Ilpo Järvinen
faf0e1b5d8 serial: tegra-tcu: Use uart_xmit_advance(), fixes icount.tx accounting
commit 1d10cd4da593bc0196a239dcc54dac24b6b0a74e upstream.

Tx'ing does not correctly account Tx'ed characters into icount.tx.
Using uart_xmit_advance() fixes the problem.

Fixes: 2d908b38d409 ("serial: Add Tegra Combined UART driver")
Cc: <stable@vger.kernel.org> # serial: Create uart_xmit_advance()
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220901143934.8850-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-28 11:11:54 +02:00
Ilpo Järvinen
0aada772fd serial: tegra: Use uart_xmit_advance(), fixes icount.tx accounting
commit 754f68044c7dd6c52534ba3e0f664830285c4b15 upstream.

DMA complete & stop paths did not correctly account Tx'ed characters
into icount.tx. Using uart_xmit_advance() fixes the problem.

Fixes: e9ea096dd225 ("serial: tegra: add serial driver")
Cc: <stable@vger.kernel.org> # serial: Create uart_xmit_advance()
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220901143934.8850-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-28 11:11:54 +02:00
Lukas Wunner
4199425b11 serial: fsl_lpuart: Reset prior to registration
commit 60f361722ad2ae5ee667d0b0545d40c42f754daf upstream.

Since commit bd5305dcabbc ("tty: serial: fsl_lpuart: do software reset
for imx7ulp and imx8qxp"), certain i.MX UARTs are reset after they've
already been registered.  Register state may thus be clobbered after
user space has begun to open and access the UART.

Avoid by performing the reset prior to registration.

Fixes: bd5305dcabbc ("tty: serial: fsl_lpuart: do software reset for imx7ulp and imx8qxp")
Cc: stable@vger.kernel.org # v5.15+
Cc: Fugang Duan <fugang.duan@nxp.com>
Cc: Sherry Sun <sherry.sun@nxp.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/72fb646c1b0b11c989850c55f52f9ff343d1b2fa.1662884345.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-28 11:11:54 +02:00