The device has a highspeed register which influences the calcualtion
of the divisor. The chip lacks support for some baudrates. When requested,
we set the divisor to the next smaller baudrate and adjust the c_cflag
accordingly.
Signed-off-by: NMatthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The architectures supported by this driver, arm and sh, have expensive
implementations of writel(), reliant on spin locks and explicit L2 cache
management. These architectures provide a cheaper writel_relaxed() which
is much better suited to peripherals that do not perform DMA. The
situation with readl()/readl_relaxed()is similar although less acute.

This driver does not use DMA and will be more power efficient and more
robust (due to absence of spin locks during console I/O) if it uses the
relaxed variants.

The driver supports COMPILE_TEST and therefore falls back to writel()
when writel_relaxed() does not exist.
Signed-off-by: NDaniel Thompson <daniel.thompson@linaro.org>
Acked-by: NSrinivas Kandagatla <srinivas.kandagatla@gmail.com>
Cc: Maxime Coquelin <maxime.coquelin@st.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: kernel@stlinux.com
Cc: linux-serial@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The patch fixes the following build error of CLPS711X serial driver for
targets without GPIOLIB support:

>> drivers/tty/serial/serial_mctrl_gpio.c:44:6: error: redefinition of 'mctrl_gpio_set'
  void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
      ^
  In file included from drivers/tty/serial/serial_mctrl_gpio.c:23:0:
  drivers/tty/serial/serial_mctrl_gpio.h:80:6: note: previous definition of 'mctrl_gpio_set' was here
  void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
      ^
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NAlexander Shiyan <shc_work@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit: e676253b [3/21] serial/8250: Add
support for RS485 IOCTLs, adds a building error on arch m32r.

All error/warnings:

   drivers/tty/serial/8250/8250_core.c: In function 'serial8250_ioctl':
>> drivers/tty/serial/8250/8250_core.c:2859:3: error: implicit declaration of function 'copy_from_user' [-Werror=implicit-function-declaration]
      if (copy_from_user(&rs485_config, (void __user *)arg,
      ^
>> drivers/tty/serial/8250/8250_core.c:2871:3: error: implicit declaration of function 'copy_to_user' [-Werror=implicit-function-declaration]
      if (copy_to_user((void __user *)arg, &up->rs485,
      ^
   cc1: some warnings being treated as errors
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The OMAP version of the 8250 can actually use 1:1 serial8250_startup().
However it needs to be extended by a wake up irq which should to be
requested & enabled at ->startup() time and disabled at ->shutdown() time.

v2…v3: properly copy callbacks
v1…v2: add shutdown callback
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no way to access a struct uart_8250_port for a specific
line. This is only required outside of the 8250/uart callbacks like for
devices' suspend & remove callbacks. For those the 8250-core provides a
wrapper like serial8250_unregister_port() which passes the struct
to the proper function based on the line argument.

For run time suspend I need access to this struct not only to make
serial_out() work but also to properly restore up->ier and up->mcr.
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Current code relies on the UART clock pre-divisor to be already
configured in the baud rate register. Calculate it in the driver
and set explicitly instead, also return the "real" effective baud
rate, which is generally slightly different from the requested value.

While at this, also ensure that break signal timing is updated when
baud rate changes.
Signed-off-by: NAlexey Charkov <alchark@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This adds simple polling functions for single-character transmit
and receive, as used by kgdb.
Signed-off-by: NAlexey Charkov <alchark@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NAlexey Charkov <alchark@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Newer WonderMedia chips introduced another flag in the UART line control
register, which controls whether RTS/CTS signalling should be handled in
the driver or by the hardware itself.

This patch ensures that the kernel can control RTS/CTS (including
disabling it altogether) by forcing this flag to software mode on affected
chips (only WM8880 so far).

Also remove the redundant copy of the binding doc, while we are here.
Signed-off-by: NAlexey Charkov <alchark@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

At present this console is optionally registered by NULL checking
arch_kgdb_ops.enable_nmi. In practice this requires the architecture
dependant code to implement some kind of control (e.g. module arguments)
to enable/disable this feature.

The kernel already provides us the perfectly adequate console= argument
to enable/disable consoles. Let's use that instead!
Signed-off-by: NDaniel Thompson <daniel.thompson@linaro.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Universally adopt container_of() for all pointer conversion from
uart_port to uart_amba_port.
Signed-off-by: NDaniel Thompson <daniel.thompson@linaro.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Looking at the get_poll_char() function of the 8250.c serial driver,
we learn:

* poll_get_char() doesn't have to save/disable/restore the interrupt
  registers. No interrupt handling is needed in this function at all.
  Remove it.

* Don't block in case there is no data available. So instead blocking
  in the do {} while loop, just return with NO_POLL_CHAR, immediately .

Additionally, while the i.MX6 register URXD[7-0] contain the RX_DATA,
the upper bits of this register (URXD[15-10]) might contain some
control flags. To ensure that these are not returned with the data
read, just mask out URXD[7-0].

These changes fix the 'hang' working with kdb:

$ echo ttymxc3 > /sys/module/kgdboc/parameters/kgdboc
$ echo g >/proc/sysrq-trigger
[0]kdb> help
...
<hang>
Signed-off-by: NDirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: NDaniel Thompson <daniel.thompson@linaro.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare for spin lock assertion; move non-trivial assignment into
function body.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Existing callers of serial8250_modem_status() [1] hold the uart port
lock; document.

[1] In-tree callers of serial8250_modem_status()

drivers/tty/serial/8250/8250_fsl.c
  fsl8250_handle_irq()

drivers/tty/serial/8250/8250_core.c
  serial8250_handle_irq()
  serial8250_console_write()
  serial8250_get_mctrl() *

* Call graphs for callers of serial8250_get_mctrl() from the function
  which acquires the uart port lock

drivers/tty/serial/serial_core.c
  uart_port_startup()
  uart_tiocmget()
  uart_set_termios()
  uart_carrier_raised()
    ops->get_mctrl() ---> serial8250_get_mctrl()
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If CONFIG_SERIAL_BFIN_CTSRTS is set, compile fails because of missing
declarations for the gpio_* api. Include necessary header.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The serial core may call the UART driver's start_tx() even if
tx is stopped; the UART driver must verify tx should be enabled
before transmitting.
Reported-by: NSam Ravnborg <sam@ravnborg.org>
cc: David S. Miller <davem@davemloft.net>
cc: <sparclinux@vger.kernel.org>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

mpc52xx_uart_send_xchar() is _identical_ to the default serial core
x_char handling behavior in uart_send_xchar().

Remove mpc52xx_uart_send_xchar().
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

START_CHAR() & STOP_CHAR() can be disabled if set to '\0'
(__DISABLED_CHAR).  UART drivers which define a send_xchar()
handler must not transmit __DISABLED_CHAR.

Document requirement.

Affected drivers:
sunsab
sunhv

cc: David S. Miller <davem@davemloft.net>
cc: <sparclinux@vger.kernel.org>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

uart_unthrottle() attempts to avoid sending START and the previous
x_char if the previous x_char has not yet been sent. However, this
optimization could leave the sender in a throttled state; for example,
if the sender is throttled and this unthrottle coincides with a manual
tcflow(TCION) from user-space, then neither START would be sent.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The UART driver is expected to clear port->x_char after
transmission while holding the port->lock. However, the serial
core fails to take the port->lock before assigning port->xchar.
This allows for the following race

CPU 0                         |  CPU 1
                              |
                              | serial8250_handle_irq
                              |   ...
                              |   serial8250_tx_chars
                              |     if (port->x_char)
                              |       serial_out(up, UART_TX, port->x_char)
uart_send_xchar               |
  port->x_char = ch           |
                              |       port->x_char = 0
  port->ops->start_tx()       |
                              |

The x_char on CPU 0 will never be sent.

Take the port->lock in uart_send_xchar() before assigning port->x_char.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The serial core expects the UART driver to transmit x_char
(START/STOP chars) even if tx is stopped and before data already
in the tx ring buffer if possible. Also, sending x_char must
not cause additional data in the tx ring buffer to transmit
if tx is stopped.

Cause x_char to be transmitted before any other data is sent.
Auto-stop tx if the tx ring buffer is empty or tx should be stopped.
Only perform one write wakeup if tx ring buffer space is below
threshold.

x_char handling in DMA mode is still broken; add FIXME.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Unwrap if() conditional; no functional change.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 06aa82e4.
This commit purports to enable auto CTS flow control for the 8250
UART driver. However, the 8250 UART driver already supports auto
CTS flow control via UART_CAP_AFE and UART_CAP_EFR. Indeed, this
patch introduces another DT attribute for which an existing firmware
flag already exists ("auto-flow-control"). Furthermore, the use of
UPF_HARD_FLOW requires the UART driver to define .throttle and
.unthrottle methods, neither of which are defined for the 8250 UART
driver (which will result in a NULL ptr dereference). Finally, this patch
supposes to fix existing bugs in the serial core for auto CTS-enabled
hardware, but does not include the class of hardware for which these
bugs exist.

CC: Murali Karicheri <m-karicheri2@ti.com>
CC: Rob Herring <robh+dt@kernel.org>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Allow Samsung serial driver to be usable on Exynos 64-bit SoC based
platforms.
Signed-off-by: NPankaj Dubey <pankaj.dubey@samsung.com>
Signed-off-by: NNaveen Krishna Chatradhi <ch.naveen@samsung.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Delete successive assignments to the same location.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression i;
@@

*i = ...;
 i = ...;
// </smpl>
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix build failure caused by missing header file:

drivers/tty/serial/nwpserial.c: In function 'wait_for_bits':
drivers/tty/serial/nwpserial.c:53:3: error: implicit declaration of function 'udelay' [-Werror=implicit-function-declaration]
Signed-off-by: NPranith Kumar <bobby.prani@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The SoC has four fully functional UARTs which use the same programming
model. They are named UART_A, UART_B, UART_C and UART_AO (Always-On)
which cannot be powered off.
Signed-off-by: NCarlo Caione <carlo@caione.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no need to init .owner field.

Based on the patch from Peter Griffin <peter.griffin@linaro.org>
"mmc: remove .owner field for drivers using module_platform_driver"

This patch removes the superflous .owner field for drivers which
use the module_platform_driver API, as this is overriden in
platform_driver_register anyway."
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Acked-by: NPeter Korsgaard <peter@korsgaard.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no need to init .owner field.

Based on the patch from Peter Griffin <peter.griffin@linaro.org>
"mmc: remove .owner field for drivers using module_platform_driver"

This patch removes the superflous .owner field for drivers which
use the module_platform_driver API, as this is overriden in
platform_driver_register anyway."
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The symbol is defined in drivers/tty/serial/8250/Kconfig as
"SERIAL_8250", not just "8250".
Signed-off-by: NDaniele Forsi <dforsi@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Frank reports that after continuing in kgdb the RX stale event
doesn't occur until after the RX fifo is filled up with exactly
the amount of characters programmed for the RX watermark (in this
case it's 48). To read a single character from the uartdm
hardware we force a stale event so that any characters in the RX
packing buffer are flushed into the RX fifo immediately instead
of waiting for a stale timeout or for the fifo to fill. Forcing
that stale event asserts the stale interrupt but we never clear
that interrupt via UART_CR_CMD_RESET_STALE_INT in the polling
functions. So when kgdb continues the stale interrupt is left
pending in the hardware and we don't timeout with a stale event,
like we usually would if a user typed one character on the
console, until the reset stale interrupt and stale event commands
are sent. Frank could get things working again by running
handle_rx_dm(). By putting enough characters into the fifo he
could trigger a watermark interrupt, and thus cause
handle_rx_dm() to run finally resetting the stale interrupt
and enabling the stale event so that single characters would
cause timeouts again.

The fix is to just do what the interrupt routine was doing all
along and clear the stale interrupt and enable the event again.
Doing this also smooths over any differences in the fifo behavior
between v1.3 and v1.4 hardware allowing us to skip forcing the
uart into single character mode.
Reviewed-by: NFrank Rowand <frank.rowand@sonymobile.com>
Tested-by: NFrank Rowand <frank.rowand@sonymobile.com>
Fixes: f7e54d7a "msm_serial: Add support for poll_{get,put}_char()"
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

CLPS711X serial driver uses the system wide registers to control the
modem signals. Now gpio-syscon driver can be used for this purposes.
mctrl_gpio helpers allow us to create GPIO bindings for any of modem/tty
control signals that extends the functionality of the driver.
This patch makes such change.

This change does not break any current DT bindings, since DT support
for this platform is not introduced yet.
Signed-off-by: NAlexander Shiyan <shc_work@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

printk replaced with corresponding dev_* .
fixed two broken user-visible strings used by the corresponding printk.
the null check for uport->dev and port->dev is removed as dev_* will check for
null while printing.
printing of dev_name(uport->dev) and dev_name(port->dev) also removed as those
are being printed by dev_* .
Signed-off-by: NSudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make the of_device_id arrays const, as it is handled as const by all OF
functions.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

fixed below checkpatch.pl warning:

WARNING: void function return statements are not generally useful
Signed-off-by: NKiran Padwal <kiran.padwal@smartplayin.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

fixed below checkpatch.pl warning:

WARNING: else is not generally useful after a break or return
Signed-off-by: NKiran Padwal <kiran.padwal@smartplayin.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

fixed below checkpatch.pl warning:

WARNING: Prefer [subsystem eg: netdev]_err([subsystem]dev, ... then dev_err(dev, ... then pr_err(...  to printk(KERN_ERR ...

WARNING: Prefer [subsystem eg: netdev]_info([subsystem]dev, ... then dev_info(dev, ... then pr_info(...  to printk(KERN_INFO ...
Signed-off-by: NKiran Padwal <kiran.padwal@smartplayin.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch fixes below checkpatch.pl warning and it remove extra blank lines:

WARNING: Missing a blank line after declarations
Signed-off-by: NKiran Padwal <kiran.padwal@smartplayin.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

fixed below checkpatch.pl warning:

WARNING: braces {} are not necessary for any arm of this statement
Signed-off-by: NKiran Padwal <kiran.padwal@smartplayin.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>