The callback is used to initialize the hardware, nothing else should be
done, i.e. we should not request interrupts (but we can and do unmask
some of them, as they might be useful for NMI entry).

As a side-effect, the patch also fixes a division by zero[1] when booting
with kgdboc options specified (e.g. kgdboc=ttyAMA0,115200n8). The issue
happens because serial core calls set_termios callback, but the driver
doesn't know clock frequency, and thus cannot calculate proper baud rate
values.

[1]
WARNING: at drivers/tty/serial/serial_core.c:400 uart_get_baud_rate+0xe8/0x14c()
Modules linked in:
[<c0018e50>] (unwind_backtrace+0x0/0xf0) from [<c0020ae8>] (warn_slowpath_common+0x4c/0x64)
[<c0020ae8>] (warn_slowpath_common+0x4c/0x64) from [<c0020b1c>] (warn_slowpath_null+0x1c/0x24)
[<c0020b1c>] (warn_slowpath_null+0x1c/0x24) from [<c0185ed8>] (uart_get_baud_rate+0xe8/0x14c)
[<c0185ed8>] (uart_get_baud_rate+0xe8/0x14c) from [<c0187078>] (pl011_set_termios+0x48/0x278)
[<c0187078>] (pl011_set_termios+0x48/0x278) from [<c01850b0>] (uart_set_options+0xe8/0x114)
[<c01850b0>] (uart_set_options+0xe8/0x114) from [<c0185de4>] (uart_poll_init+0xd4/0xe0)
[<c0185de4>] (uart_poll_init+0xd4/0xe0) from [<c016da8c>] (tty_find_polling_driver+0x100/0x17c)
[<c016da8c>] (tty_find_polling_driver+0x100/0x17c) from [<c0188538>] (configure_kgdboc+0xc8/0x1b8)
[<c0188538>] (configure_kgdboc+0xc8/0x1b8) from [<c00088a4>] (do_one_initcall+0x30/0x168)
[<c00088a4>] (do_one_initcall+0x30/0x168) from [<c033784c>] (do_basic_setup+0x94/0xc8)
[<c033784c>] (do_basic_setup+0x94/0xc8) from [<c03378e0>] (kernel_init+0x60/0xf4)
[<c03378e0>] (kernel_init+0x60/0xf4) from [<c00144a0>] (kernel_thread_exit+0x0/0x8)
---[ end trace 7d41c9186f342c40 ]---
Division by zero in kernel.
[<c0018e50>] (unwind_backtrace+0x0/0xf0) from [<c014546c>] (Ldiv0+0x8/0x10)
[<c014546c>] (Ldiv0+0x8/0x10) from [<c0187098>] (pl011_set_termios+0x68/0x278)
[<c0187098>] (pl011_set_termios+0x68/0x278) from [<c01850b0>] (uart_set_options+0xe8/0x114)
[<c01850b0>] (uart_set_options+0xe8/0x114) from [<c0185de4>] (uart_poll_init+0xd4/0xe0)
[<c0185de4>] (uart_poll_init+0xd4/0xe0) from [<c016da8c>] (tty_find_polling_driver+0x100/0x17c)
[<c016da8c>] (tty_find_polling_driver+0x100/0x17c) from [<c0188538>] (configure_kgdboc+0xc8/0x1b8)
[<c0188538>] (configure_kgdboc+0xc8/0x1b8) from [<c00088a4>] (do_one_initcall+0x30/0x168)
[<c00088a4>] (do_one_initcall+0x30/0x168) from [<c033784c>] (do_basic_setup+0x94/0xc8)
[<c033784c>] (do_basic_setup+0x94/0xc8) from [<c03378e0>] (kernel_init+0x60/0xf4)
[<c03378e0>] (kernel_init+0x60/0xf4) from [<c00144a0>] (kernel_thread_exit+0x0/0x8)
Division by zero in kernel.
[<c0018e50>] (unwind_backtrace+0x0/0xf0) from [<c014546c>] (Ldiv0+0x8/0x10)
[<c014546c>] (Ldiv0+0x8/0x10) from [<c0183a98>] (uart_update_timeout+0x4c/0x5c)
[<c0183a98>] (uart_update_timeout+0x4c/0x5c) from [<c01870f8>] (pl011_set_termios+0xc8/0x278)
[<c01870f8>] (pl011_set_termios+0xc8/0x278) from [<c01850b0>] (uart_set_options+0xe8/0x114)
[<c01850b0>] (uart_set_options+0xe8/0x114) from [<c0185de4>] (uart_poll_init+0xd4/0xe0)
[<c0185de4>] (uart_poll_init+0xd4/0xe0) from [<c016da8c>] (tty_find_polling_driver+0x100/0x17c)
[<c016da8c>] (tty_find_polling_driver+0x100/0x17c) from [<c0188538>] (configure_kgdboc+0xc8/0x1b8)
[<c0188538>] (configure_kgdboc+0xc8/0x1b8) from [<c00088a4>] (do_one_initcall+0x30/0x168)
[<c00088a4>] (do_one_initcall+0x30/0x168) from [<c033784c>] (do_basic_setup+0x94/0xc8)
[<c033784c>] (do_basic_setup+0x94/0xc8) from [<c03378e0>] (kernel_init+0x60/0xf4)
[<c03378e0>] (kernel_init+0x60/0xf4) from [<c00144a0>] (kernel_thread_exit+0x0/0x8)
Signed-off-by: NAnton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

It was noticed that polling drivers (like KGDB) are not able to use
serial ports if the ports were not previously initialized via console.
I.e.  when booting with console=ttyAMA0 kgdboc=ttyAMA0, everything works
fine, but with console=ttyFOO kgdboc=ttyAMA0, the kgdboc doesn't work.

This is because we don't initialize the hardware. Calling ->startup() is
not an option, because drivers request interrupts there, and drivers
fail to handle situations when tty isn't opened with interrupts enabled.

So, we have to implement a new callback (actually, tty_ops already have
a similar callback), which does everything needed to initialize just the
hardware.
Signed-off-by: NAnton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This works around a few glitches in the ST version of the PL011
serial driver when using very high baud rates, as we do in the
Ux500: 3, 3.25, 4 and 4.05 Mbps.

Problem Observed/rootcause:

When using high baud-rates, and the baudrate*8 is getting close to
the provided clock frequency (so a division factor close to 1), when
using bursts of characters (so they are abutted), then it seems as if
there is not enough time to detect the beginning of the start-bit which
is a timing reference for the entire character, and thus the sampling
moment of character bits is moving towards the end of each bit, instead
of the middle.

Fix:
Increase slightly the RX baud rate of the UART above the theoretical
baudrate by 5%. This will definitely give more margin time to the
UART_RX to correctly sample the data at the middle of the bit period.

Also fix the ages old copy-paste error in the very stressed comment,
it's referencing the registers used in the PL010 driver rather than
the PL011 ones.
Signed-off-by: NGuillaume Jaunet <guillaume.jaunet@stericsson.com>
Signed-off-by: NChristophe Arnal <christophe.arnal@stericsson.com>
Signed-off-by: NMatthias Locher <matthias.locher@stericsson.com>
Signed-off-by: NRajanikanth HV <rajanikanth.hv@stericsson.com>
Cc: stable <stable@vger.kernel.org>
Cc: Bibek Basu <bibek.basu@stericsson.com>
Cc: Par-Gunnar Hjalmdahl <par-gunnar.hjalmdahl@stericsson.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NAlexander Shiyan <shc_work@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The kernel will handle IXON/IXOFF/IXANY in software if the hardware
doesn't do it.
Signed-off-by: NAlexander Shiyan <shc_work@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NAlexander Shiyan <shc_work@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The following patch allows users to use KGDB over serial console on
board based on Samsung SOC. It has been tested on a board using
exynos5.

[dianders: changed poll to return NO_POLL_CHAR, which appears to
fix 'help' in kgdb; also updated commit message]
Signed-off-by: NJulien Pichon <pichon.jln@gmail.com>
Signed-off-by: NDoug Anderson <dianders@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

MAXIDL is the timeout after which a receive buffer is closed when not full if
no more characters are received. We calculate it from the baudrate so that the
duration is always the same at standard rates: about 4ms. At 9600 bauds it gives
a timeout of 4 characters, which is the timeout on the 8250 UART.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

maxidl register was set to fifo size. There is no reason to set this
register to same value as fifo size. Setting it now to 0x10 by default
as in the UCC UART driver.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Setting the fifo to only 1 byte generates one interrupt every 1ms at 9600 bauds.
This is too much. This patch reduces the threshold to speeds below 2400 bauds
like in the 8250 UART driver.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch fixes a desynchronisation problem with CPM UART driver on
Powerpc MPC8xx. The problem happens if data is received before the device
is open by the user application.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Apparently the same card model has two IDs, so this patch
complements the commit 39aced68
adding the missing one.
Signed-off-by: NFlavio Leitner <fbl@redhat.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch does the following
- In case of errors if there least one data character in the RX FIFO
read it otherwise it may stall the receiver.

This is recommended in the interrupt reset method in the table 23-246 of
the omap4 TRM.
Signed-off-by: NShubhrajyoti D <shubhrajyoti@ti.com>
Reviewed-by: NFelipe Balbi <balbi@ti.com>
Tested-by: NKevin Hilman <khilman@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The legacy serial driver will detect the Winbond CIR device as a serial
port, since it looks exactly like a serial port unless you know what
it is from the PNP ID.

Here we track this port as a special PORT_8250_CIR type, preventing the
legacy serial driver from probing it.
Signed-off-by: NSean Young <sean@mess.org>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We first probe the legacy serial ports and then check pnp. If there
is a non-standard configuration then this might not work, also this
change is needed so we can blacklist Winbond CIR based on PNP ID.

For this to work the 8250_pnp driver must be merged into the 8250
module.
Signed-off-by: NSean Young <sean@mess.org>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Drop the check for "up" being valid on suspend/resume callbacks.
It should be valid always. Get rid of the "pdata" check also as
serial_omap_get_context_loss_count() checks for it.

Tested on omap4 panda and 3630 based Beagle board.
Signed-off-by: NSourav Poddar <sourav.poddar@ti.com>
Reviewed-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

platform_get_drvdata always retrun a valid value after probe succeed.

It also fixed smatch warnings:
drivers/tty/serial/imx.c:1376 serial_imx_suspend() warn: variable dereferenced before check 'sport' (see line 1372)
drivers/tty/serial/imx.c:1392 serial_imx_resume() warn: variable dereferenced before check 'sport' (see line 1388)
Signed-off-by: NRichard Zhao <richard.zhao@freescale.com>
Acked-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NRichard Zhao <richard.zhao@freescale.com>
Acked-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The autoconfig prints messages while holding the
port's spinlock and that causes a deadlock when
using serial console.
Signed-off-by: NFlavio Leitner <fbl@redhat.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We end up dropping the mutex twice on some errors. We don't want to do
that.
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If a serial driver is called post hangup with a second DCD event then we
will attempt to get the ldisc of NULL. Check we have a tty before trying to
do anything with it.

This is still only safe within the uart layer if the caller holds the
relevant uart locks. We could do with a version where the tty is passed for
more general use.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Alan says these are not production ready, and users should be told this,
so put the "(EXPERIMENTAL)" marking back in the Kconfig entry string.
Reported-by: NAlan Cox <alan@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As discussed at the kernel summit this year, CONFIG_EXPERIMENTAL means
nothing, so let's get rid of it.

Cc: Kees Cook <keescook@chromium.org>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Return the value returned by the failing function instead
of -1 (which does not convey the right error information).

Fixes the following smatch warning:
drivers/tty/serial/samsung.c:1687 s3c24xx_serial_modinit() info:
why not propagate 'ret' from uart_register_driver() instead of -1?
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In the trace we print the wrong values for N(R) on an I frame.
Correct the mask.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Otherwise we start trying to use a bogus channel - ungood.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We don't want to free a random address if the entry is wrong, cover
this and WARN if it ever happens.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

HVC returns a size of -1 bytes for the write room in some cases.
This is bogus and not handled by the tty layer at all.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The mxs_auart_probe() gets the device by the get_device().
So we should put the device in the error path to balance the
device's reference counter.
Signed-off-by: NHuang Shijie <b32955@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These workarounds do not apply for CONFIG_ARCH_OMAP2PLUS at all,
so let's make it just CONFIG_ARCH_OMAP1.

This is needed to for ARM common zImage changes for
omap2+ to avoid including plat and mach headers.
Signed-off-by: NTony Lindgren <tony@atomide.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

On some machines using a specific hardware for console screen output,
the update of the pixel frame buffer does not work correctly when
using command line edition. This may be due to a memory cache bug
in the machine on which the problem has been found, but an other
solution is possible.

This patch proposes to avoid touching directly the pixel frame buffer
and to rebuild each character using the standard putc() function
on command line edition.

The resulting code is smaller and not obviously slower (no read
access to the pixel frame buffer).

Tested on a Cubox (ARM Marvell Dove 88AP510 SoC).
Signed-off-by: NJean-François Moine <moinejf@free.fr>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The driver explicitly requests a clock rate for the UART, but it is
off by a factor of four from the dividers that it programs into the
UART.  Fix this by setting the rate to 1/4 of the current value.
Signed-off-by: NDavid Brown <davidb@codeaurora.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The bug flag .interrupt_may_hang is not used since commit
4fd0690b
"serial: pl011: implement workaround for CTS clear event issue"
so delete it.

Cc: Rajanikanth H.V <rajanikanth.hv@stericsson.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The dereference should be moved below the NULL test.

spatch with a semantic match is used to found this.
(http://coccinelle.lip6.fr/)
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Request pins using pinctrl framework. Only show a warning
on error as some boards set the pins in the bootloader
even if CONFIG_PINCTRL is enabled.
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

OMAP Architecture code, passes a few function
pointers for UART driver to use in order to
properly implement Power Management and Wakeup
capabilities.

The problem is that those function pointers,
which are passed (ab)using platform_data on
non-DT kernels, can't be passed down to drivers
through DT.

commit e5b57c03 (serial: omap: define helpers
for pdata function pointers) failed to take DT
kernels into consideration and caused a regression
to DT kernel boot.

Fix that by (re-)adding a check for valid pdata
pointer together with valid pdata->$FUNCTION
pointer.
Reported-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Tested-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

when rebasing patches on top of Greg's tty-next,
it looks like automerge broke a few things which
I didn't catch (for whatever reason I didn't
have OMAP Serial enabled on .config) so I ended
up breaking the build on Greg's tty-next branch.

Fix the breakage by re-adding the three missing
members on struct uart_omap_port.
Reported-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Added tty_device_create_release() and bound to dev->release in
tty_register_device_attr().
Added tty_port_register_device_attr() and used in uart_add_one_port()
instead of tty_register_device_attr().
Signed-off-by: NTomas Hlavacek <tmshlvck@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Added file /sys/devices/.../tty/ttySX/uartclk to allow reading
uartclk value in struct uart_port in serial_core via sysfs.

tty_register_device() has been generalized and refactored in order
to add support for setting drvdata and attribute_group to the device.
Signed-off-by: NTomas Hlavacek <tmshlvck@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fixes these build errors:

In file included from drivers/tty/serial/sccnxp.c:20:0:
include/linux/serial_core.h: In function 'uart_handle_break':
include/linux/serial_core.h:543:30: error: dereferencing pointer to incomplete type
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>