commit 677fe555cbfb188af58cce105f4dae9505e58c31 upstream.

commit 9ec1882df2 (tty: serial: imx: console write routing is unsafe
on SMP) introduced a recursive locking bug in imx_console_write().

The callchain is:

imx_rxint()
  spin_lock_irqsave(&sport->port.lock,flags);
  ...
  uart_handle_sysrq_char();
    sysrq_function();
      printk();
        imx_console_write();
          spin_lock_irqsave(&sport->port.lock,flags); <--- DEAD

The bad news is that the kernel debugging facilities can dectect the
problem, but the printks never surface on the serial console for
obvious reasons.

There is a similar issue with oops_in_progress. If the kernel crashes
we really don't want to be stuck on the lock and unable to tell what
happened.

In general most UP originated drivers miss these checks and nobody
ever notices because CONFIG_PROVE_LOCKING seems to be still ignored by
a large number of developers.

The solution is to avoid locking in the sysrq case and trylock in the
oops_in_progress case.

This scheme is used in other drivers as well and it would be nice if
we could move this to a common place, so the usual copy/paste/modify
bugs can be avoided.

Now there is another issue with this scheme:

CPU0 	    	     	 CPU1
printk()
			 rxint()
			   sysrq_detection() -> sets port->sysrq
			 return from interrupt
  console_write()
     if (port->sysrq)
     	avoid locking

port->sysrq is reset with the next receive character. So as long as
the port->sysrq is not reset and this can take an endless amount of
time if after the break no futher receive character follows, all
console writes happen unlocked.

While the current writer is protected against other console writers by
the console sem, it's unprotected against open/close or other
operations which fiddle with the port. That's what the above mentioned
commit tried to solve.

That's an issue in all drivers which use that scheme and unfortunately
there is no easy workaround. The only solution is to have a separate
indicator port->sysrq_cpu. uart_handle_sysrq_char() then sets it to
smp_processor_id() before calling into handle_sysrq() and resets it to
-1 after that. Then change the locking check to:

     if (port->sysrq_cpu == smp_processor_id())
     	 locked = 0;
     else if (oops_in_progress)
         locked = spin_trylock_irqsave(port->lock, flags);
     else
  	 spin_lock_irqsave(port->lock, flags);

That would force all other cpus into the spin_lock path. Problem
solved, but that's way beyond the scope of this fix and really wants
to be implemented in a common function which calls the uart specific
write function to avoid another gazillion of hard to debug
copy/paste/modify bugs.

Reported-and-tested-by: Tim Sander <tim@krieglstein.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit a6833214cfc6fa8a7c59426af77794cc190c6cfc upstream.

With the patch "serial: mxs-auart: fix the wrong RTS hardware flow control" the
mainline mxs-uart driver now sets RTSEN only when hardware flow control is
enabled via software. It is not possible any longer to set RTS manually via
software. However, the manual modification is a valid operation.
Regain the possibility to set RTS via software and only set RTSEN when hardware
flow control is explicitly enabled via settermios cflag CRTSCTS.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Reviewed-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ebebd49a8eab5e9aa1b1f8f1614ccc3c2120f886 upstream.

Add support for the UART device present in Broadcom TruManage capable
NetXtreme chips (ie: 5761m 5762, and 5725).

This implementation has a hidden transmit FIFO, so running in single-byte
interrupt mode results in too many interrupts.  The UART_CAP_HFIFO
capability was added to track this.  It continues to reload the THR as long
as the THRE and TSRE bits are set in the LSR up to a specified limit (1024
is used here).

Signed-off-by: Stephen Hurd <shurd@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 68e56cb3a068f9c30971c6117fbbd1e32918e49e upstream.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit a6dd114e16cbc4410049a90a8a67b967333d108d upstream.

In case of error, function of_clk_get() returns ERR_PTR()
and never returns NULL. The NULL test in the return value
check should be replaced with IS_ERR().

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 014b9b4ce84281ccb3d723c792bed19815f3571a upstream.

When shut down SPI port, it's possible that MRDY has been asserted and a SPI
timer was activated waiting for SRDY assert, in the case, it needs to delete
this timer.

Signed-off-by: Chen Jun <jun.d.chen@intel.com>
Signed-off-by: channing <chao.bi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The spi_device_id table is supposed to be zero-terminated.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 957ee7270d632245b43f6feb0e70d9a5e9ea6cf6
(serial: omap: fix software flow control).

As Russell has pointed out, that commit isn't fixing
Software Flow Control at all, and it actually makes
it even more broken.

It was agreed to revert this commit and use Russell's
latest UART patches instead.

Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull TTY fixes from Greg Kroah-Hartman:
 "Here are some tty and serial driver fixes for your 3.7-rc1 tree.

  Again, the UABI header file fixes, and a number of build and runtime
  serial driver bugfixes that solve problems people have been reporting
  (the staging driver is a tty driver, hence the fixes coming in through
  this tree.)

  All of these have been in the linux-next tree for a while.

  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"

* tag 'tty-3.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  staging: dgrp: check return value of alloc_tty_driver
  staging: dgrp: check for NULL pointer in (un)register_proc_table
  serial/8250_hp300: Missing 8250 register interface conversion bits
  UAPI: (Scripted) Disintegrate include/linux/hsi
  tty: serial: sccnxp: Fix bug with unterminated platform_id list
  staging: serial: dgrp: Add missing #include <linux/uaccess.h>
  serial: sccnxp: Allows the driver to be compiled as a module
  tty: Fix bogus "callbacks suppressed" messages
  net, TTY: initialize tty->driver_data before usage

commit 2655a2c76f80d91da34faa8f4e114d1793435ed3 ("8250: use the 8250
register interface not the legacy one") forgot to fully switch one
instance of struct uart_port to struct uart_8250_port, causing the
following compile failure:

drivers/tty/serial/8250/8250_hp300.c: In function ‘hpdca_init_one’:
drivers/tty/serial/8250/8250_hp300.c:174: error: ‘uart’ undeclared (first use in this function)
drivers/tty/serial/8250/8250_hp300.c:174: error: (Each undeclared identifier is reported only once
drivers/tty/serial/8250/8250_hp300.c:174: error: for each function it appears in.)

This went unnoticed in -next, as CONFIG_HPDCA is not set to y by
allmodconfig.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Philip Blundell <philb@gnu.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>