linux-stable.git/drivers/tty/serial/8250, branch linux-5.16.y

serial: 8250: fix XOFF/XON sending when DMA is used

2022-04-08T12:06:27+00:00

[ Upstream commit f58c252e30cf74f68b0054293adc03b5923b9f0e ]

When 8250 UART is using DMA, x_char (XON/XOFF) is never sent
to the wire. After this change, x_char is injected correctly.

Create uart_xchar_out() helper for sending the x_char out and
accounting related to it. It seems that almost every driver
does these same steps with x_char. Except for 8250, however,
almost all currently lack .serial_out so they cannot immediately
take advantage of this new helper.

The downside of this patch is that it might reintroduce
the problems some devices faced with mixed DMA/non-DMA transfer
which caused revert f967fc8f165f (Revert "serial: 8250_dma:
don't bother DMA with small transfers"). However, the impact
should be limited to cases with XON/XOFF (that didn't work
with DMA capable devices to begin with so this problem is not
very likely to cause a major issue, if any at all).

Fixes: 9ee4b83e51f74 ("serial: 8250: Add support for dmaengine")
Reported-by: Gilles Buloz 
Tested-by: Gilles Buloz 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20220314091432.4288-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250: Fix race condition in RTS-after-send handling

2022-04-08T12:06:23+00:00

[ Upstream commit dedab69fd650ea74710b2e626e63fd35584ef773 ]

Set em485->active_timer = NULL isn't always enough to take out the stop
timer. While there is a check that it acts in the right state (i.e.
waiting for RTS-after-send to pass after sending some chars) but the
following might happen:

 - CPU1: some chars send, shifter becomes empty, stop tx timer armed
 - CPU0: more chars send before RTS-after-send expired
 - CPU0: shifter empty irq, port lock taken
 - CPU1: tx timer triggers, waits for port lock
 - CPU0: em485->active_timer = &em485->stop_tx_timer, hrtimer_start(),
   releases lock()
 - CPU1: get lock, see em485->active_timer == &em485->stop_tx_timer,
   tear down RTS too early

This fix bases on research done by Steffen Trumtrar.

Fixes: b86f86e8e7c5 ("serial: 8250: fix potential deadlock in rs485-mode")
Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20220215160236.344236-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_lpss: Balance reference count for PCI DMA device

2022-04-08T12:06:23+00:00

[ Upstream commit 5318f70da7e82649d794fc27d8a127c22aa3566e ]

The pci_get_slot() increases its reference count, the caller
must decrement the reference count by calling pci_dev_put().

Fixes: 9a1870ce812e ("serial: 8250: don't use slave_id of dma_slave_config")
Depends-on: a13e19cf3dc1 ("serial: 8250_lpss: split LPSS driver to separate module")
Reported-by: Qing Wang 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20220223151240.70248-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_mid: Balance reference count for PCI DMA device

2022-04-08T12:06:23+00:00

[ Upstream commit 67ec6dd0b257bd81b4e9fcac89b29da72f6265e5 ]

The pci_get_slot() increases its reference count, the caller
must decrement the reference count by calling pci_dev_put().

Fixes: 90b9aacf912a ("serial: 8250_pci: add Intel Tangier support")
Fixes: f549e94effa1 ("serial: 8250_pci: add Intel Penwell ports")
Reported-by: Qing Wang 
Signed-off-by: Andy Shevchenko 
Depends-on: d9eda9bab237 ("serial: 8250_pci: Intel MID UART support to its own driver")
Link: https://lore.kernel.org/r/20220215100920.41984-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_aspeed_vuart: add PORT_ASPEED_VUART port type

2022-04-08T12:06:22+00:00

[ Upstream commit a603ca60cebff8589882427a67f870ed946b3fc8 ]

Commit 54da3e381c2b ("serial: 8250_aspeed_vuart: use UPF_IOREMAP to
set up register mapping") fixed a bug that had, as a side-effect,
prevented the 8250_aspeed_vuart driver from enabling the VUART's
FIFOs.  However, fixing that (and hence enabling the FIFOs) has in
turn revealed what appears to be a hardware bug in the ASPEED VUART in
which the host-side THRE bit doesn't get if the BMC-side receive FIFO
trigger level is set to anything but one byte.  This causes problems
for polled-mode writes from the host -- for example, Linux kernel
console writes proceed at a glacial pace (less than 100 bytes per
second) because the write path waits for a 10ms timeout to expire
after every character instead of being able to continue on to the next
character upon seeing THRE asserted.  (GRUB behaves similarly.)

As a workaround, introduce a new port type for the ASPEED VUART that's
identical to PORT_16550A as it had previously been using, but with
UART_FCR_R_TRIG_00 instead to set the receive FIFO trigger level to
one byte, which (experimentally) seems to avoid the problematic THRE
behavior.

Fixes: 54da3e381c2b ("serial: 8250_aspeed_vuart: use UPF_IOREMAP to set up register mapping")
Tested-by: Konstantin Aladyshev 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Zev Weiss 
Link: https://lore.kernel.org/r/20220211004203.14915-1-zev@bewilderbeest.net
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: parisc: GSC: fix build when IOSAPIC is not set

2022-02-23T11:05:46+00:00

commit 6e8793674bb0d1135ca0e5c9f7e16fecbf815926 upstream.

There is a build error when using a kernel .config file from
'kernel test robot' for a different build problem:

hppa64-linux-ld: drivers/tty/serial/8250/8250_gsc.o: in function `.LC3':
(.data.rel.ro+0x18): undefined reference to `iosapic_serial_irq'

when:
  CONFIG_GSC=y
  CONFIG_SERIO_GSCPS2=y
  CONFIG_SERIAL_8250_GSC=y
  CONFIG_PCI is not set
    and hence PCI_LBA is not set.
  IOSAPIC depends on PCI_LBA, so IOSAPIC is not set/enabled.

Make the use of iosapic_serial_irq() conditional to fix the build error.

Signed-off-by: Randy Dunlap 
Reported-by: kernel test robot 
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: linux-parisc@vger.kernel.org
Cc: Greg Kroah-Hartman 
Cc: linux-serial@vger.kernel.org
Cc: Jiri Slaby 
Cc: Johan Hovold 
Suggested-by: Helge Deller 
Signed-off-by: Helge Deller 
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller 
Signed-off-by: Greg Kroah-Hartman

tty: Add support for Brainboxes UC cards.

2022-02-01T16:29:07+00:00

commit 152d1afa834c84530828ee031cf07a00e0fc0b8c upstream.

This commit adds support for the some of the Brainboxes PCI range of
cards, including the UC-101, UC-235/246, UC-257, UC-268, UC-275/279,
UC-302, UC-310, UC-313, UC-320/324, UC-346, UC-357, UC-368
and UC-420/431.

Signed-off-by: Cameron Williams 
Cc: stable 
Link: https://lore.kernel.org/r/AM5PR0202MB2564688493F7DD9B9C610827C45E9@AM5PR0202MB2564.eurprd02.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman

serial: 8250: of: Fix mapped region size when using reg-offset property

2022-02-01T16:29:06+00:00

commit d06b1cf28297e27127d3da54753a3a01a2fa2f28 upstream.

8250_of supports a reg-offset property which is intended to handle
cases where the device registers start at an offset inside the region
of memory allocated to the device. The Xilinx 16550 UART, for which this
support was initially added, requires this. However, the code did not
adjust the overall size of the mapped region accordingly, causing the
driver to request an area of memory past the end of the device's
allocation. For example, if the UART was allocated an address of
0xb0130000, size of 0x10000 and reg-offset of 0x1000 in the device
tree, the region of memory reserved was b0131000-b0140fff, which caused
the driver for the region starting at b0140000 to fail to probe.

Fix this by subtracting reg-offset from the mapped region size.

Fixes: b912b5e2cfb3 ([POWERPC] Xilinx: of_serial support for Xilinx uart 16550.)
Cc: stable 
Signed-off-by: Robert Hancock 
Link: https://lore.kernel.org/r/20220112194214.881844-1-robert.hancock@calian.com
Signed-off-by: Greg Kroah-Hartman

serial: 8250_dw: Add StarFive JH7100 quirk

2022-01-27T11:02:17+00:00

[ Upstream commit 57dcb6ec85d59e04285b7dcf10924bb819c8e46f ]

On the StarFive JH7100 RISC-V SoC the UART core clocks can't be set to
exactly 16 * 115200Hz and many other common bitrates. Trying this will
only result in a higher input clock, but low enough that the UART's
internal divisor can't come close enough to the baud rate target.
So rather than try to set the input clock it's better to skip the
clk_set_rate call and rely solely on the UART's internal divisor.

Signed-off-by: Emil Renner Berthing 
Reviewed-by: Andy Shevchenko 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/r/20211116150119.2171-15-kernel@esmil.dk
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

serial: 8250_bcm7271: Propagate error codes from brcmuart_probe()

2022-01-27T11:01:53+00:00

[ Upstream commit c195438f1e84de8fa46b4f5264d12379bee6e9a1 ]

In case of failures brcmuart_probe() always returned -ENODEV, this
isn't correct for example platform_get_irq_byname() may return
-EPROBE_DEFER to handle such cases propagate error codes in
brcmuart_probe() in case of failures.

Fixes: 41a469482de25 ("serial: 8250: Add new 8250-core based Broadcom STB driver")
Acked-by: Florian Fainelli 
Signed-off-by: Lad Prabhakar 
Link: https://lore.kernel.org/r/20211224142917.6966-4-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin