linux-stable.git/drivers/tty, branch v4.9.22

serial: 8250_omap: Add OMAP_DMA_TX_KICK quirk for AM437x

2017-04-12T10:41:19+00:00

[ Upstream commit b6ffcf21082300519bc4f9c3d24f61207cc9eae4 ]

UART uses as EDMA as dma engine on AM437x SoC and therefore, requires
OMAP_DMA_TX_KICK quirk just like AM33xx. So, enable OMAP_DMA_TX_KICK
quirk for AM437x platform as well. While at that, drop use of
of_machine_is_compatible() and instead pass quirks via device data.

Signed-off-by: Vignesh R 
Acked-by: Tony Lindgren 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

serial: mxs-auart: Fix baudrate calculation

2017-04-08T07:30:34+00:00

commit a6040bc610554c66088fda3608ae5d6307c548e4 upstream.

The reference manual for the i.MX28 recommends to calculate the divisor
as

	divisor = (UARTCLK * 32) / baud rate, rounded to the nearest integer

, so let's do this. For a typical setup of UARTCLK = 24 MHz and baud
rate = 115200 this changes the divisor from 6666 to 6667 and so the
actual baud rate improves from 115211.521 Bd (error ≅ 0.01 %) to
115194.240 Bd (error ≅ 0.005 %).

Signed-off-by: Uwe Kleine-König 
Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: fix TX path in atmel_console_write()

2017-04-08T07:30:34+00:00

commit 497e1e16f45c70574dc9922c7f75c642c2162119 upstream.

A side effect of 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA
from transmitting in stop_tx") is that the console can be called with
TX path disabled. Then the system would hang trying to push charecters
out in atmel_console_putchar().

Signed-off-by: Nicolas Ferre 
Fixes: 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx")
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: fix race condition (TX+DMA)

2017-04-08T07:30:34+00:00

commit 31ca2c63fdc0aee725cbd4f207c1256f5deaabde upstream.

If uart_flush_buffer() is called between atmel_tx_dma() and
atmel_complete_tx_dma(), the circular buffer has been cleared, but not
atmel_port->tx_len.
That leads to a circular buffer overflow (dumping (UART_XMIT_SIZE -
atmel_port->tx_len) bytes).

Tested-by: Nicolas Ferre 
Signed-off-by: Richard Genoud 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Detach low-level driver during PCI error recovery

2017-03-22T11:43:39+00:00

[ Upstream commit f209fa03fc9d131b3108c2e4936181eabab87416 ]

During a PCI error recovery, like the ones provoked by EEH in the ppc64
platform, all IO to the device must be blocked while the recovery is
completed.  Current 8250_pci implementation only suspends the port
instead of detaching it, which doesn't prevent incoming accesses like
TIOCMGET and TIOCMSET calls from reaching the device.  Those end up
racing with the EEH recovery, crashing it.  Similar races were also
observed when opening the device and when shutting it down during
recovery.

This patch implements a more robust IO blockage for the 8250_pci
recovery by unregistering the port at the beginning of the procedure and
re-adding it afterwards.  Since the port is detached from the uart
layer, we can be sure that no request will make through to the device
during recovery.  This is similar to the solution used by the JSM serial
driver.

I thank Peter Hurley  for valuable input on
this one over one year ago.

Signed-off-by: Gabriel Krisman Bertazi 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

serial: samsung: Continue to work if DMA request fails

2017-03-18T11:14:33+00:00

commit f98c7bce570bdbe344b74ff5daa7dfeef3f22929 upstream.

If DMA is not available (even when configured in DeviceTree), the driver
will fail the startup procedure thus making serial console not
available.

For example this causes boot failure on QEMU ARMv7 (Exynos4210, SMDKC210):
    [    1.302575] OF: amba_device_add() failed (-19) for /amba/pdma@12680000
    ...
    [   11.435732] samsung-uart 13800000.serial: DMA request failed
    [   72.963893] samsung-uart 13800000.serial: DMA request failed
    [   73.143361] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000

DMA is not necessary for serial to work, so continue with UART startup
after emitting a warning.

Fixes: 62c37eedb74c ("serial: samsung: add dma reqest/release functions")
Signed-off-by: Krzysztof Kozlowski 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Add MKS Tenta SCOM-0800 and SCOM-0801 cards

2017-03-15T02:02:40+00:00

commit 1c9c858e2ff8ae8024a3d75d2ed080063af43754 upstream.

The MKS Instruments SCOM-0800 and SCOM-0801 cards (originally by Tenta
Technologies) are 3U CompactPCI serial cards with 4 and 8 serial ports,
respectively.  The first 4 ports are implemented by an OX16PCI954 chip,
and the second 4 ports are implemented by an OX16C954 chip on a local
bus, bridged by the second PCI function of the OX16PCI954.  The ports
are jumper-selectable as RS-232 and RS-422/485, and the UARTs use a
non-standard oscillator frequency of 20 MHz (base_baud = 1250000).

Signed-off-by: Ian Abbott 
Signed-off-by: Greg Kroah-Hartman

tty: n_hdlc: get rid of racy n_hdlc.tbuf

2017-03-15T02:02:40+00:00

commit 82f2341c94d270421f383641b7cd670e474db56b upstream.

Currently N_HDLC line discipline uses a self-made singly linked list for
data buffers and has n_hdlc.tbuf pointer for buffer retransmitting after
an error.

The commit be10eb7589337e5defbe214dae038a53dd21add8
("tty: n_hdlc add buffer flushing") introduced racy access to n_hdlc.tbuf.
After tx error concurrent flush_tx_queue() and n_hdlc_send_frames() can put
one data buffer to tx_free_buf_list twice. That causes double free in
n_hdlc_release().

Let's use standard kernel linked list and get rid of n_hdlc.tbuf:
in case of tx error put current data buffer after the head of tx_buf_list.

Signed-off-by: Alexander Popov 
Signed-off-by: Greg Kroah-Hartman

tty: serial: msm: Fix module autoload

2017-02-26T10:10:51+00:00

commit abe81f3b8ed2996e1712d26d38ff6b73f582c616 upstream.

If the driver is built as a module, autoload won't work because the module
alias information is not filled. So user-space can't match the registered
device with the corresponding module.

Export the module alias information using the MODULE_DEVICE_TABLE() macro.

Before this patch:

$ modinfo drivers/tty/serial/msm_serial.ko | grep alias
$

After this patch:

$ modinfo drivers/tty/serial/msm_serial.ko | grep alias
alias:          of:N*T*Cqcom,msm-uartdmC*
alias:          of:N*T*Cqcom,msm-uartdm
alias:          of:N*T*Cqcom,msm-uartC*
alias:          of:N*T*Cqcom,msm-uart

Signed-off-by: Javier Martinez Canillas 
Acked-by: Bjorn Andersson 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

Clearing FIFOs in RS485 emulation mode causes subsequent transmits to break

2017-01-19T19:18:03+00:00

commit 2bed8a8e70729f996af92042d3ad0f11870acc1f upstream.

When in RS485 emulation mode, __do_stop_tx_rs485() calls
serial8250_clear_fifos().  This not only clears the FIFOs, but also sets
all bits in their control register (UART_FCR) to 0.

One of the effects of this is the disabling of the FIFOs, which turns
them into single-byte holding registers.  The rest of the driver doesn't
know this, which results in the lions share of characters passed into a
write call to be dropped.

(I can supply logic analyzer screenshots if necessary)

This fix replaces the serial8250_clear_fifos() call to
serial8250_clear_and_reinit_fifos() - this prevents the "dropped
characters" issue from manifesting again while retaining the requirement
of clearing the RX FIFO after transmission if the SER_RS485_RX_DURING_TX
flag is disabled.

Signed-off-by: Daniel Jedrychowski 
Signed-off-by: Greg Kroah-Hartman