linux-stable.git/drivers/tty, branch v4.4.196

tty/serial: atmel: reschedule TX after RX was started

2019-09-21T05:12:48+00:00

commit d2ace81bf902a9f11d52e59e5d232d2255a0e353 upstream.

When half-duplex RS485 communication is used, after RX is started, TX
tasklet still needs to be  scheduled tasklet. This avoids console freezing
when more data is to be transmitted, if the serial communication is not
closed.

Fixes: 69646d7a3689 ("tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped")
Signed-off-by: Razvan Stefanescu 
Cc: stable 
Link: https://lore.kernel.org/r/20190813074025.16218-1-razvan.stefanescu@microchip.com
Signed-off-by: Greg Kroah-Hartman

serial: sprd: correct the wrong sequence of arguments

2019-09-21T05:12:47+00:00

commit 9c801e313195addaf11c16e155f50789d6ebfd19 upstream.

The sequence of arguments which was passed to handle_lsr_errors() didn't
match the parameters defined in that function, &lsr was passed to flag
and &flag was passed to lsr, this patch fixed that.

Fixes: b7396a38fb28 ("tty/serial: Add Spreadtrum sc9836-uart driver support")
Signed-off-by: Chunyan Zhang 
Signed-off-by: Chunyan Zhang 
Cc: stable 
Link: https://lore.kernel.org/r/20190905074151.5268-1-zhang.lyra@gmail.com
Signed-off-by: Greg Kroah-Hartman

tty/ldsem, locking/rwsem: Add missing ACQUIRE to read_failed sleep loop

2019-08-25T08:52:51+00:00

[ Upstream commit 952041a8639a7a3a73a2b6573cb8aa8518bc39f8 ]

While reviewing rwsem down_slowpath, Will noticed ldsem had a copy of
a bug we just found for rwsem.

  X = 0;

  CPU0			CPU1

  rwsem_down_read()
    for (;;) {
      set_current_state(TASK_UNINTERRUPTIBLE);

                        X = 1;
                        rwsem_up_write();
                          rwsem_mark_wake()
                            atomic_long_add(adjustment, &sem->count);
                            smp_store_release(&waiter->task, NULL);

      if (!waiter.task)
        break;

      ...
    }

  r = X;

Allows 'r == 0'.

Reported-by: Will Deacon 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Will Deacon 
Cc: Linus Torvalds 
Cc: Peter Hurley 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: 4898e640caf0 ("tty: Add timed, writer-prioritized rw semaphore")
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

serial: sh-sci: Fix TX DMA buffer flushing and workqueue races

2019-08-04T07:34:58+00:00

[ Upstream commit 8493eab02608b0e82f67b892aa72882e510c31d0 ]

When uart_flush_buffer() is called, the .flush_buffer() callback zeroes
the tx_dma_len field.  This may race with the work queue function
handling transmit DMA requests:

  1. If the buffer is flushed before the first DMA API call,
     dmaengine_prep_slave_single() may be called with a zero length,
     causing the DMA request to never complete, leading to messages
     like:

        rcar-dmac e7300000.dma-controller: Channel Address Error happen

     and, with debug enabled:

	sh-sci e6e88000.serial: sci_dma_tx_work_fn: ffff800639b55000: 0...0, cookie 126

     and DMA timeouts.

  2. If the buffer is flushed after the first DMA API call, but before
     the second, dma_sync_single_for_device() may be called with a zero
     length, causing the transmit data not to be flushed to RAM, and
     leading to stale data being output.

Fix this by:
  1. Letting sci_dma_tx_work_fn() return immediately if the transmit
     buffer is empty,
  2. Extending the critical section to cover all DMA preparational work,
     so tx_dma_len stays consistent for all of it,
  3. Using local copies of circ_buf.head and circ_buf.tail, to make sure
     they match the actual operation above.

Reported-by: Eugeniu Rosca 
Suggested-by: Yoshihiro Shimoda 
Signed-off-by: Geert Uytterhoeven 
Reviewed-by: Eugeniu Rosca 
Tested-by: Eugeniu Rosca 
Link: https://lore.kernel.org/r/20190624123540.20629-2-geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: serial: msm_serial: avoid system lockup condition

2019-08-04T07:34:56+00:00

[ Upstream commit ba3684f99f1b25d2a30b6956d02d339d7acb9799 ]

The function msm_wait_for_xmitr can be taken with interrupts
disabled. In order to avoid a potential system lockup - demonstrated
under stress testing conditions on SoC QCS404/5 - make sure we wait
for a bounded amount of time.

Tested on SoC QCS404.

Signed-off-by: Jorge Ramirez-Ortiz 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty/serial: digicolor: Fix digicolor-usart already registered warning

2019-08-04T07:34:56+00:00

[ Upstream commit c7ad9ba0611c53cfe194223db02e3bca015f0674 ]

When modprobe/rmmod/modprobe module, if platform_driver_register() fails,
the kernel complained,

  proc_dir_entry 'driver/digicolor-usart' already registered
  WARNING: CPU: 1 PID: 5636 at fs/proc/generic.c:360 proc_register+0x19d/0x270

Fix this by adding uart_unregister_driver() when platform_driver_register() fails.

Reported-by: Hulk Robot 
Signed-off-by: Kefeng Wang 
Acked-by: Baruch Siach 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: serial: cpm_uart - fix init when SMC is relocated

2019-08-04T07:34:56+00:00

[ Upstream commit 06aaa3d066db87e8478522d910285141d44b1e58 ]

SMC relocation can also be activated earlier by the bootloader,
so the driver's behaviour cannot rely on selected kernel config.

When the SMC is relocated, CPM_CR_INIT_TRX cannot be used.

But the only thing CPM_CR_INIT_TRX does is to clear the
rstate and tstate registers, so this can be done manually,
even when SMC is not relocated.

Signed-off-by: Christophe Leroy 
Fixes: 9ab921201444 ("cpm_uart: fix non-console port startup bug")
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: max310x: Fix invalid baudrate divisors calculator

2019-08-04T07:34:56+00:00

[ Upstream commit 35240ba26a932b279a513f66fa4cabfd7af55221 ]

Current calculator doesn't do it' job quite correct. First of all the
max310x baud-rates generator supports the divisor being less than 16.
In this case the x2/x4 modes can be used to double or quadruple
the reference frequency. But the current baud-rate setter function
just filters all these modes out by the first condition and setups
these modes only if there is a clocks-baud division remainder. The former
doesn't seem right at all, since enabling the x2/x4 modes causes the line
noise tolerance reduction and should be only used as a last resort to
enable a requested too high baud-rate.

Finally the fraction is supposed to be calculated from D = Fref/(c*baud)
formulae, but not from D % 16, which causes the precision loss. So to speak
the current baud-rate calculator code works well only if the baud perfectly
fits to the uart reference input frequency.

Lets fix the calculator by implementing the algo fully compliant with
the fractional baud-rate generator described in the datasheet:
D = Fref / (c*baud), where c={16,8,4} is the x1/x2/x4 rate mode
respectively, Fref - reference input frequency. The divisor fraction is
calculated from the same formulae, but making sure it is found with a
resolution of 0.0625 (four bits).

Signed-off-by: Serge Semin 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: rocket: fix incorrect forward declaration of 'rp_init()'

2019-07-10T07:56:44+00:00

[ Upstream commit 423ea3255424b954947d167681b71ded1b8fca53 ]

Make the forward declaration actually match the real function
definition, something that previous versions of gcc had just ignored.

This is another patch to fix new warnings from gcc-9 before I start the
merge window pulls.  I don't want to miss legitimate new warnings just
because my system update brought a new compiler with new warnings.

Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

sunhv: Fix device naming inconsistency between sunhv_console and sunhv_reg

2019-06-22T06:18:25+00:00

[ Upstream commit 07a6d63eb1b54b5fb38092780fe618dfe1d96e23 ]

In d5a2aa24, the name in struct console sunhv_console was changed from "ttyS"
to "ttyHV" while the name in struct uart_ops sunhv_pops remained unchanged.

This results in the hypervisor console device to be listed as "ttyHV0" under
/proc/consoles while the device node is still named "ttyS0":

root@osaka:~# cat /proc/consoles
ttyHV0               -W- (EC p  )    4:64
tty0                 -WU (E     )    4:1
root@osaka:~# readlink /sys/dev/char/4:64
../../devices/root/f02836f0/f0285690/tty/ttyS0
root@osaka:~#

This means that any userland code which tries to determine the name of the
device file of the hypervisor console device can not rely on the information
provided by /proc/consoles. In particular, booting current versions of debian-
installer inside a SPARC LDOM will fail with the installer unable to determine
the console device.

After renaming the device in struct uart_ops sunhv_pops to "ttyHV" as well,
the inconsistency is fixed and it is possible again to determine the name
of the device file of the hypervisor console device by reading the contents
of /proc/console:

root@osaka:~# cat /proc/consoles
ttyHV0               -W- (EC p  )    4:64
tty0                 -WU (E     )    4:1
root@osaka:~# readlink /sys/dev/char/4:64
../../devices/root/f02836f0/f0285690/tty/ttyHV0
root@osaka:~#

With this change, debian-installer works correctly when installing inside
a SPARC LDOM.

Signed-off-by: John Paul Adrian Glaubitz 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman