linux-stable.git/drivers/tty/serial, branch linux-3.14.y

serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios()

2016-06-01T19:12:48+00:00

commit b8995f527aac143e83d3900ff39357651ea4e0f6 upstream.

This patch fixes the broken serial log when changing the clock source
of uart device. Before disabling the original clock source, this patch
enables the new clock source to protect the clock off state for a split second.

Signed-off-by: Chanwoo Choi 
Reviewed-by: Marek Szyprowski 
Signed-off-by: Greg Kroah-Hartman 
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Krzysztof Kozlowski

serial: sh-sci: Remove cpufreq notifier to fix crash/deadlock

2016-05-04T21:51:25+00:00

commit ff1cab374ad98f4b9f408525ca9c08992b4ed784 upstream.

The BSP team noticed that there is spin/mutex lock issue on sh-sci when
CPUFREQ is used.  The issue is that the notifier function may call
mutex_lock() while the spinlock is held, which can lead to a BUG().
This may happen if CPUFREQ is changed while another CPU calls
clk_get_rate().

Taking the spinlock was added to the notifier function in commit
e552de2413edad1a ("sh-sci: add platform device private data"), to
protect the list of serial ports against modification during traversal.
At that time the Common Clock Framework didn't exist yet, and
clk_get_rate() just returned clk->rate without taking a mutex.
Note that since commit d535a2305facf9b4 ("serial: sh-sci: Require a
device per port mapping."), there's no longer a list of serial ports to
traverse, and taking the spinlock became superfluous.

To fix the issue, just remove the cpufreq notifier:
  1. The notifier doesn't work correctly: all it does is update stored
     clock rates; it does not update the divider in the hardware.
     The divider will only be updated when calling sci_set_termios().
     I believe this was broken back in 2004, when the old
     drivers/char/sh-sci.c driver (where the notifier did update the
     divider) was replaced by drivers/serial/sh-sci.c (where the
     notifier just updated port->uartclk).
     Cfr. full-history-linux commits 6f8deaef2e9675d9 ("[PATCH] sh: port
     sh-sci driver to the new API") and 3f73fe878dc9210a ("[PATCH]
     Remove old sh-sci driver").
  2. On modern SoCs, the sh-sci parent clock rate is no longer related
     to the CPU clock rate anyway, so using a cpufreq notifier is
     futile.

Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Greg Kroah-Hartman

8250: use callbacks to access UART_DLL/UART_DLM

2016-04-12T16:12:44+00:00

commit 0b41ce991052022c030fd868e03877700220b090 upstream.

Some UART HW has a single register combining UART_DLL/UART_DLM
(this was probably forgotten in the change that introduced the
callbacks, commit b32b19b8ffc05cbd3bf91c65e205f6a912ca15d9)

Fixes: b32b19b8ffc0 ("[SERIAL] 8250: set divisor register correctly ...")

Signed-off-by: Sebastian Frias 
Reviewed-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Correct uartclk for xr17v35x expansion chips

2016-02-25T19:58:52+00:00

commit 899f0c1c7dbcc487fdc8756a49ff70b1d5d75f89 upstream.

The internal clock of the master chip, which is usually 125MHz, is only half
(62.5MHz) for the slave chips. So we have to adjust the uartclk for all the
slave ports. Therefor we add a new function to determine if a slave chip is
present and update pci_xr17v35x_setup accordingly.

Signed-off-by: Soeren Grunewald 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Add support for 12 port Exar boards

2015-11-09T20:50:26+00:00

commit be32c0cf0462c36f482b5ddcff1d8371be1e183c upstream.

The Exar XR17V358 can also be combined with a XR17V354 chip to act as a
single 12 port chip. This works the same way as the combining two XR17V358
chips. But the reported device id then is 0x4358.

Signed-off-by: Soeren Grunewald 
Signed-off-by: Greg Kroah-Hartman

serial: 8250_pci: Add support for 16 port Exar boards

2015-11-09T20:50:26+00:00

commit 96a5d18bc1338786fecac73599f1681f59a59a8e upstream.

The Exar XR17V358 chip usually provides only 8 ports. But two chips can be
combined to act as a single 16 port chip. Therefor one chip is configured
as master the second as slave by connecting the mode pin to VCC (master)
or GND (slave).

Then the master chip is reporting a different device-id depending on
whether a slave is detected or not. The UARTs 8-15 are addressed from
0x2000-0x3fff. So the offset of 0x400 from UART to UART can be used to
address all 16 ports as before.

See: https://www.exar.com/common/content/document.ashx?id=1587 page 11

Signed-off-by: Soeren Grunewald 
Signed-off-by: Greg Kroah-Hartman

serial: 8250: don't bind to SMSC IrCC IR port

2015-09-21T17:02:18+00:00

commit ffa34de03bcfbfa88d8352942bc238bb48e94e2d upstream.

SMSC IrCC SIR/FIR port should not be bound to by
(legacy) serial driver so its own driver (smsc-ircc2)
can bind to it.

Signed-off-by: Maciej Szmigiero 
Signed-off-by: Greg Kroah-Hartman

serial: imx: Fix DMA handling for IDLE condition aborts

2015-06-23T00:01:23+00:00

commit 392bceedb107a3dc1d4287e63d7670d08f702feb upstream.

The driver configures the IDLE condition to interrupt the SDMA engine.
Since the SDMA UART ROM script doesn't clear the IDLE bit itself, this
caused repeated 1-byte DMA transfers, regardless of available data in the
RX FIFO. Also, when returning due to the IDLE condition, the UART ROM
script already increased its counter, causing residue to be off by one.

This patch clears the IDLE condition to avoid repeated 1-byte DMA transfers
and decreases count by when the DMA transfer was aborted due to the IDLE
condition, fixing serial transfers using DMA on i.MX6Q.

Reported-by: Peter Seiderer 
Signed-off-by: Philipp Zabel 
Tested-by: Fabio Estevam 
Signed-off-by: Greg Kroah-Hartman

tty/serial: at91: maxburst was missing for dma transfers

2015-05-13T12:16:57+00:00

commit a8d4e01637902311c5643b69a5c80e2805f04054 upstream.

Maxburst was not set when doing the dma slave configuration. This value
is checked by the recently introduced xdmac. It causes an error when
doing the slave configuration and so prevents from using dma.

Signed-off-by: Ludovic Desroches 
Acked-by: Nicolas Ferre 
Signed-off-by: Greg Kroah-Hartman

serial: of-serial: Remove device_type = "serial" registration

2015-05-13T12:16:56+00:00

commit 6befa9d883385c580369a2cc9e53fbf329771f6d upstream.

Do not probe all serial drivers by of_serial.c which are using
device_type = "serial"; property. Only drivers which have valid
compatible strings listed in the driver should be probed.

When PORT_UNKNOWN is setup probe will fail anyway.

Arnd quotation about driver historical background:
"when I wrote that driver initially, the idea was that it would
get used as a stub to hook up all other serial drivers but after
that, the common code learned to create platform devices from DT"

This patch fix the problem with on the system with xilinx_uartps and
16550a where of_serial failed to register for xilinx_uartps and because
of irq_dispose_mapping() removed irq_desc. Then when xilinx_uartps was asking
for irq with request_irq() EINVAL is returned.

Signed-off-by: Michal Simek 
Acked-by: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman