When a serial port is configured for RTS/CTS flow control, serial core
will disable the transmitter if it observes CTS is de-asserted. This is
perfectly reasonable and appropriate when the UART lacks the ability to
automatically perform CTS flow control.

However, if the UART hardware can manage flow control automatically, it
is important that software not get involved.  When the DesignWare UART
enables 16C750 style auto-RTS/CTS it stops generating interrupts for
changes in CTS state so software mostly stays out of the way.  However,
it does report the true state of CTS in the MSR so software may notice
it is de-asserted and respond by improperly disabling the transmitter.
Once this happens the transmitter will be blocked forever.

To avoid this situation, we simply lie to the 8250 and serial core by
reporting that CTS is asserted whenever auto-RTS/CTS mode is enabled.
Signed-off-by: NTim Kryger <tim.kryger@linaro.org>
Reviewed-by: NMatt Porter <matt.porter@linaro.org>
Reviewed-by: NMarkus Mayer <markus.mayer@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The recent patch to add RS485 contained a bug whereby the IER
interrupt was cleared down incorrectly.

This patch fixes the problem.
Signed-off-by: NMark Jackson <mpfj@newflow.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Function wait_for_xmitr is invoked only on functions that either depend
on CONFIG_CONSOLE_POLL or CONFIG_SERIAL_PCH_UART_CONSOLE.

This patch fixes the following warning:

drivers/tty/serial/pch_uart.c:1504:13: warning: ‘wait_for_xmitr’ defined but not used [-Wunused-function]
Signed-off-by: NLuis Henriques <luis.henriques@canonical.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

we defined some special properties for hardware flow control, document them
for DT-binding.
Signed-off-by: NQipan Li <Qipan.Li@csr.com>
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

for USP-based UART, we use two gpios as RTS and CST pins.
Signed-off-by: NQipan Li <Qipan.Li@csr.com>
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

pinctrl core will get default pinmux, so drop it in the sirfsoc serial driver.

Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch adds RS485 support to the OMAP serial driver, as
defined in:-

Documentation/devicetree/bindings/serial/rs485.txt

When a UART transmitter is connected to (eg) a RS485 driver, it is
necessary to turn the driver on/off as quickly as possible.  This is
best achieved in the serial driver itself (rather than in userspace
where the latency can be quite large).

This patch allows a GPIO pin to be defined (via DT) that controls
the enabling of the driver at the start of a message, and disables
the driver when the message has been completed.

When RS485 is disabled, the RTS pin is set to on.
Signed-off-by: NMark Jackson <mpfj@newflow.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove unneeded error handling on the result of a call to
platform_get_resource when the value is passed to devm_ioremap_resource.

Move the call to platform_get_resource adjacent to the call to
devm_ioremap_resource to make the connection between them more clear.

A simplified version of the semantic patch that makes this change is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression pdev,res,n,e,e1;
expression ret != 0;
identifier l;
@@

- res = platform_get_resource(pdev, IORESOURCE_MEM, n);
  ... when != res
- if (res == NULL) { ... \(goto l;\|return ret;\) }
  ... when != res
+ res = platform_get_resource(pdev, IORESOURCE_MEM, n);
  e = devm_ioremap_resource(e1, res);
// </smpl>
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix the following sparse warnings:

drivers/tty/serial/amba-pl011.c:687:20: warning: context imbalance in 'pl011_dma_flush_buffer' - unexpected unlock
drivers/tty/serial/amba-pl011.c:1200:13: warning: context imbalance in 'pl011_rx_chars' - unexpected unlock
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The clock should be checked with the proper IS_ERR() api before using it.
Signed-off-by: NJohn Crispin <blogic@openwrt.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Enable the clock if one is present when setting up the console.
Signed-off-by: NThomas Langer <thomas.langer@lantiq.com>
Acked-by: NJohn Crispin <blogic@openwrt.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

__initdata should be placed between the variable name and equal
sign for the variable to be placed in the intended section.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

__initdata should be placed between the variable name and equal
sign for the variable to be placed in the intended section.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Acked-by: NSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

'cons' is a pointer; thus NULL should be used instead of 0.
Also, local symbols are staticized.
Fix the following sparse warnings:

drivers/tty/serial/serial-tegra.c:1209:27: warning: Using plain integer as NULL pointer
drivers/tty/serial/serial-tegra.c:1240:29: warning: symbol 'tegra20_uart_chip_data' was not declared. Should it be static?
drivers/tty/serial/serial-tegra.c:1246:29: warning: symbol 'tegra30_uart_chip_data' was not declared. Should it be static?
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix the following sparse warning:

drivers/tty/serial/msm_serial.c:237:37: error: incompatible types in comparison expression (different type sizes)
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

ioc4_serial_attach_one() is used only in this file.
Also, ioc4_serial is not used; it can be removed.
Fix the following sparse warnings:

drivers/tty/serial/ioc4_serial.c:300:3: warning: symbol 'ioc4_serial' was not declared. Should it be static?
drivers/tty/serial/ioc4_serial.c:2771:1: warning: symbol 'ioc4_serial_attach_one' was not declared. Should it be static?
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Acked-by: NPatrick Gefre <pfg@sgi.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

icom_port->uart_port.membase is (unsigned char __iomem *); thus,
casting (unsigned char __iomem *) is necessary to fix the
following warning. Also, local symbols are staticized.

drivers/tty/serial/icom.c:108:26: warning: symbol 'start_proc' was not declared. Should it be static?
drivers/tty/serial/icom.c:116:26: warning: symbol 'stop_proc' was not declared. Should it be static?
drivers/tty/serial/icom.c:123:25: warning: symbol 'int_mask_tbl' was not declared. Should it be static?
drivers/tty/serial/icom.c:1569:54: warning: incorrect type in assignment (different address spaces)
drivers/tty/serial/icom.c:1569:54:    expected unsigned char [noderef] <asn:2>*membase
drivers/tty/serial/icom.c:1569:54:    got char *<noident>
drivers/tty/serial/icom.c:1090:9: warning: cast truncates bits from constant value (ffffff7f becomes 7f)
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These local symbols are used only in this file.
Fix the following sparse warnings:

drivers/tty/serial/timbuart.c:165:6: warning: symbol 'timbuart_handle_rx_port' was not declared. Should it be static?
drivers/tty/serial/timbuart.c:187:6: warning: symbol 'timbuart_tasklet' was not declared. Should it be static?
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

max->port.membase is (unsigned char __iomem *); thus,
casting (unsigned char __iomem *) is necessary to fix
the following warning. Also, serial_m3110_ops() is staticized.

drivers/tty/serial/mrst_max3110.c:716:17: warning: symbol 'serial_m3110_ops' was not declared. Should it be static?
drivers/tty/serial/mrst_max3110.c:847:27: warning: incorrect type in assignment (different address spaces)
drivers/tty/serial/mrst_max3110.c:847:27:    expected unsigned char [noderef] <asn:2>*membase
drivers/tty/serial/mrst_max3110.c:847:27:    got void *<noident>
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix the following sparse warning:

drivers/tty/serial/8250/8250_early.c:196:26: error: incompatible types in comparison expression (different type sizes)
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

port->membase is (unsigned char __iomem *), not (unsigned long *)
__set_bit() uses (unsigned long *) as the second argument.
Thus, casting (unsigned long *)(unsigned long) is necessary
to fix the following sparse warnings.

drivers/tty/serial/samsung.c:142:33: warning: cast removes address space of expression
drivers/tty/serial/samsung.c:161:33: warning: cast removes address space of expression
drivers/tty/serial/samsung.c:176:33: warning: cast removes address space of expression
drivers/tty/serial/samsung.c:526:40: warning: cast removes address space of expression
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These local symbols are used only in this file.
Fix the following sparse warnings:

drivers/tty/serial/sirfsoc_uart.c:147:6: warning: symbol 'sirfsoc_uart_start_tx' was not declared. Should it be static?
drivers/tty/serial/sirfsoc_uart.c:636:5: warning: symbol 'sirfsoc_uart_probe' was not declared. Should it be static?
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Acked-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Universal Serial Ports (USP) can be used as PCM, UART, SPI,
I2S etc. this makes the USP work as UART. the basic work
flow is same with UART controller, the main difference will
be offset of registers and bits.

this patch makes the old sirfsoc uart driver support both
sirf UART and USP-based UART by making their differences
become private data.
Signed-off-by: NQipan Li <Qipan.Li@csr.com>
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

the marco and coming new CSR multiple SoCs have SET/CLR pair for
INTEN registers to avoid some read-modify-write.

this patch adds support for this and make the driver support current
up and coming mp SoCs.
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

devicetrees may have the linux,stdout-path property to specify the
console. This patch adds support to the i.MX serial driver for this.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

devicetrees may have a linux,stdout-path property in the chosen
node describing the console device. This adds a helper function
to match a device against this property so a driver can call
add_preferred_console for a matching device.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Acked-by: NRob Herring <rob.herring@calxeda.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use devm_* functions in order to simplify cleanup
paths.
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Lockdep reports a circular lock dependency between
atomic_read_lock and termios_rwsem [1]. However, a lock
order deadlock is not possible since CPU1 only holds a
read lock which cannot prevent CPU0 from also acquiring
a read lock on the same r/w semaphore.

Unfortunately, lockdep cannot currently distinguish whether
the locks are read or write for any particular lock graph,
merely that the locks _were_ previously read and/or write.

Until lockdep is fixed, re-order atomic_read_lock so
termios_rwsem can be dropped and reacquired without
triggering lockdep.

Patch based on original posted here https://lkml.org/lkml/2013/8/1/510
by Sergey Senozhatsky <sergey.senozhatsky@gmail.com>

[1] Initial lockdep report from Artem Savkov <artem.savkov@gmail.com>

 ======================================================
 [ INFO: possible circular locking dependency detected ]
 3.11.0-rc3-next-20130730+ #140 Tainted: G        W
 -------------------------------------------------------
 bash/1198 is trying to acquire lock:
  (&tty->termios_rwsem){++++..}, at: [<ffffffff816aa3bb>] n_tty_read+0x49b/0x660

 but task is already holding lock:
  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff816aa0f0>] n_tty_read+0x1d0/0x660

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (&ldata->atomic_read_lock){+.+...}:
        [<ffffffff811111cc>] validate_chain+0x73c/0x850
        [<ffffffff811117e0>] __lock_acquire+0x500/0x5d0
        [<ffffffff81111a29>] lock_acquire+0x179/0x1d0
        [<ffffffff81d34b9c>] mutex_lock_interruptible_nested+0x7c/0x540
        [<ffffffff816aa0f0>] n_tty_read+0x1d0/0x660
        [<ffffffff816a3bb6>] tty_read+0x86/0xf0
        [<ffffffff811f21d3>] vfs_read+0xc3/0x130
        [<ffffffff811f2702>] SyS_read+0x62/0xa0
        [<ffffffff81d45259>] system_call_fastpath+0x16/0x1b

 -> #0 (&tty->termios_rwsem){++++..}:
        [<ffffffff8111064f>] check_prev_add+0x14f/0x590
        [<ffffffff811111cc>] validate_chain+0x73c/0x850
        [<ffffffff811117e0>] __lock_acquire+0x500/0x5d0
        [<ffffffff81111a29>] lock_acquire+0x179/0x1d0
        [<ffffffff81d372c1>] down_read+0x51/0xa0
        [<ffffffff816aa3bb>] n_tty_read+0x49b/0x660
        [<ffffffff816a3bb6>] tty_read+0x86/0xf0
        [<ffffffff811f21d3>] vfs_read+0xc3/0x130
        [<ffffffff811f2702>] SyS_read+0x62/0xa0
        [<ffffffff81d45259>] system_call_fastpath+0x16/0x1b

 other info that might help us debug this:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&ldata->atomic_read_lock);
                                lock(&tty->termios_rwsem);
                                lock(&ldata->atomic_read_lock);
   lock(&tty->termios_rwsem);

  *** DEADLOCK ***

 2 locks held by bash/1198:
  #0:  (&tty->ldisc_sem){.+.+.+}, at: [<ffffffff816ade04>] tty_ldisc_ref_wait+0x24/0x60
  #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff816aa0f0>] n_tty_read+0x1d0/0x660

 stack backtrace:
 CPU: 1 PID: 1198 Comm: bash Tainted: G        W    3.11.0-rc3-next-20130730+ #140
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
  0000000000000000 ffff880019acdb28 ffffffff81d34074 0000000000000002
  0000000000000000 ffff880019acdb78 ffffffff8110ed75 ffff880019acdb98
  ffff880019fd0000 ffff880019acdb78 ffff880019fd0638 ffff880019fd0670
 Call Trace:
  [<ffffffff81d34074>] dump_stack+0x59/0x7d
  [<ffffffff8110ed75>] print_circular_bug+0x105/0x120
  [<ffffffff8111064f>] check_prev_add+0x14f/0x590
  [<ffffffff81d3ab5f>] ? _raw_spin_unlock_irq+0x4f/0x70
  [<ffffffff811111cc>] validate_chain+0x73c/0x850
  [<ffffffff8110ae0f>] ? trace_hardirqs_off_caller+0x1f/0x190
  [<ffffffff811117e0>] __lock_acquire+0x500/0x5d0
  [<ffffffff81111a29>] lock_acquire+0x179/0x1d0
  [<ffffffff816aa3bb>] ? n_tty_read+0x49b/0x660
  [<ffffffff81d372c1>] down_read+0x51/0xa0
  [<ffffffff816aa3bb>] ? n_tty_read+0x49b/0x660
  [<ffffffff816aa3bb>] n_tty_read+0x49b/0x660
  [<ffffffff810e4130>] ? try_to_wake_up+0x210/0x210
  [<ffffffff816a3bb6>] tty_read+0x86/0xf0
  [<ffffffff811f21d3>] vfs_read+0xc3/0x130
  [<ffffffff811f2702>] SyS_read+0x62/0xa0
  [<ffffffff815e24ee>] ? trace_hardirqs_on_thunk+0x3a/0x3f
  [<ffffffff81d45259>] system_call_fastpath+0x16/0x1b
Reported-by: NArtem Savkov <artem.savkov@gmail.com>
Reported-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These local symbols are used only in this file.
Fix the following sparse warnings:

drivers/tty/serial/pxa.c:793:17: warning: symbol 'serial_pxa_pops' was not declared. Should it be static?
drivers/tty/serial/pxa.c:971:12: warning: symbol 'serial_pxa_init' was not declared. Should it be static?
drivers/tty/serial/pxa.c:986:13: warning: symbol 'serial_pxa_exit' was not declared. Should it be static?
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This #if-0'd block wouldn't compile, so let's dispose it.
Signed-off-by: NDaniel Mack <zonque@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch guards the console_drivers list to be corrupted. The
for_each_console() macro insist on a strictly forward list ended by NULL:

 con0->next->con1->next->NULL

Without this patch it may happen easily to destroy this list for example by
adding 'earlyprintk' twice, especially on embedded devices where the early
console is often a single static instance.  This will result in the following
list:

 con0->next->con0

This in turn will result in an endless loop in console_unlock() later on by
printing the first __log_buf line endlessly.
Signed-off-by: NAndreas Bießmann <andreas@biessmann.de>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The virtual console has (undocumented) module parameters to set the
colors for italic and underlined text, but the default text color was
hardcoded for some reason.  This made it impossible to change the color
for startup messages, or to set the default for new virtual consoles.
Add a module parameter for that, and document the entire bunch.

Any hacker who thinks that a command prompt on a "black screen with
white font" is not supicious enough can now use the kernel parameter
vt.color=10 to get a nice, evil green.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add the RTS/CTS property for auart0 which means we enable the
DMA support for it.
Signed-off-by: NHuang Shijie <b32955@freescale.com>
Acked-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The MXS_AUART_DMA_CONFIG is originally used to check if the DT node
is configured with the DMA property.

But now, the MXS_AUART_DMA_CONFIG is set unconditionally in the
serial_mxs_probe_dt(), so the check in the mxs_auart_settermios() is
not necessary anymore. This patch removes this macro.
Signed-off-by: NHuang Shijie <shijie8@gmail.com>
Acked-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The original DMA support works only when RTS/CTS is enabled.
(see the "e8001632 serial: mxs-auart: add the DMA support for mx28")
But after several patches, DMA support has lost this limit.
(see the "bcc20f9e serial: mxs-auart: move to use generic DMA helper")

So an UART without the RTS/CTS lines may also enables the DMA support,
in which case the UART may gets unpredictable results.

This patch adds an optional property for the UART DT node
which indicates the UART has RTS and CTS lines, and it also means you
enable the DMA support for this UART.

This patch also adds a macro MXS_AUART_RTSCTS, and uses it to check
RTS/CTS before we enable the DMA for the UART.
Signed-off-by: NHuang Shijie <b32955@freescale.com>
Signed-off-by: NHuang Shijie <shijie8@gmail.com>
Acked-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We want the tty fixes in here as well.
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull dmaengine fixes from Vinod Koul:
 "Two fixes for slave dmaengine.  The first fixes cyclic dma transfers
  for pl330 and the second one makes us return the correct error code on
  probe"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dma: pl330: Fix cyclic transfers
  pch_dma: fix error return code in pch_dma_probe()

Pull drm fix from Dave Airlie:
 "Just a quick fix that a few people have reported, be nice to have in
  asap"

The drm tree seems to be very confused about 64-bit divides.  Here it
uses a slow 64-by-64 bit divide to divide by a small constant.  Oh well.
Doesn't look performance-critical, just stupid.

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/radeon: fix 64 bit divide in SI spm code

Commit 46a1c2c7 ("vfs: export lseek_execute() to modules") broke the
tmpfs SEEK_DATA/SEEK_HOLE implementation, because vfs_setpos() converts
the carefully prepared -ENXIO to -EINVAL.  Other filesystems avoid it in
error cases: do the same in tmpfs.
Signed-off-by: NHugh Dickins <hughd@google.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>