linux-toradex.git/drivers/tty/serial, branch v3.0.16

pch_uart: Support new device LAPIS Semiconductor ML7831 IOH

2011-11-26T17:09:57+00:00

commit 8249f743f732ccbc3056428945ab1d9bd36d46bf upstream.

ML7831 is companion chip for Intel Atom E6xx series.

Signed-off-by: Tomoya MORINAGA 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

pch_uart: Fix DMA resource leak issue

2011-11-26T17:09:57+00:00

commit 90f04c2926cfb5bf74533b0a7766bc896f6a0c0e upstream.

Changing UART mode PIO->DMA->PIO->DMA like below, pch_uart driver can't get
DMA channel resource.

setserial /dev/ttyPCH0 ^low_latency
setserial /dev/ttyPCH0 low_latency

CAUSE:
Changing mode using setserial command, ".startup" function which gets DMA
channel is called before ".verify_port" function which sets
dma-flag(use_dma/use_dma_flag) as 1.

PIO->DMA
  .startup: Since dma-flag is 0, DMA channel is not requested.
  .verify_port: dma-flag is set as 1.
  .shutdown: N/A

DMA->PIO
  .startup: Since dma-flag is 1, DMA channel is requested.
  .verify_port: dma-flag is set as 0.
  .shutdown: Since dma-flag is 0, DMA channel is not released.

This means DMA channel resource leak occurs.
Next time, this driver can't get DMA channel resource forever.

MODIFICATION:
  Currently, when release DMA channel resource, this driver checks dma-flag.
  However, this specification occurs the above issue.
  This driver must check whether dma_request_channel is executed or not.
  The values are saved in private data variable "chan_tx/chan_tx".
  These variables mean if the value is NULL, DMA channel is not requested,
  if not NULL, DMA channel is requested.

This patch fixes the issue.

Signed-off-by: Tomoya MORINAGA 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

pch_uart: Fix hw-flow control issue

2011-11-26T17:09:57+00:00

commit a1d7cfe29f13cf45f8094929864b9c66bf0cd91b upstream.

Using hardware flow control,
currently, register of the control-bit(AFE) is not set.
This patch fixes the issue.

Signed-off-by: Tomoya MORINAGA 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

jsm: remove buggy write queue

2011-11-11T17:36:24+00:00

commit 9d898966c4a07e4a5092215b5a2829d0ef02baa2 upstream.

jsm uses a write queue that copies from uart_core circular buffer. This
copying however has some bugs, like not wrapping the head counter. Since
this write queue is also a circular buffer, the consumer function is
ready to use the uart_core circular buffer directly.

This buggy copying function was making some bytes be dropped when
transmitting to a raw tty, doing something like this.

[root@hostname ~]$ cat /dev/ttyn1 > cascardo/dump &
[1] 2658
[root@hostname ~]$ cat /proc/tty/drivers > /dev/ttyn0
[root@hostname ~]$ cat /proc/tty/drivers
/dev/tty             /dev/tty        5       0 system:/dev/tty
/dev/console         /dev/console    5       1 system:console
/dev/ptmx            /dev/ptmx       5       2 system
/dev/vc/0            /dev/vc/0       4       0 system:vtmaster
jsm                  /dev/ttyn     250 0-31 serial
serial               /dev/ttyS       4 64-95 serial
hvc                  /dev/hvc      229 0-7 system
pty_slave            /dev/pts      136 0-1048575 pty:slave
pty_master           /dev/ptm      128 0-1048575 pty:master
unknown              /dev/tty        4 1-63 console
[root@hostname ~]$ cat cascardo/dump
/dev/tty             /dev/tty        5       0 system:/dev/tty
/dev/console         /dev/console    5       1 system:console
/dev/ptmx            /dev/ptmx       5       2 system
/dev/vc/0            /dev/vc/0       4       0 system:vtmaste[root@hostname ~]$

This patch drops the driver write queue entirely, using the circular
buffer from uart_core only.

Signed-off-by: Thadeu Lima de Souza Cascardo 
Signed-off-by: Greg Kroah-Hartman

serial-core: power up uart port early before we do set_termios when resuming

2011-11-11T17:35:15+00:00

commit 94abc56f4d90f289ea32a0a11d3577fcd8cb28fb upstream.

The following patch removed uart_change_pm() in uart_resume_port():

commit 5933a161abcb8d83a2c145177f48027c3c0a8995
Author: Yin Kangkai 
    serial-core: reset the console speed on resume

It will break the pxa serial driver when the system resumes from suspend mode
as it will try to set baud rate divider register in set_termios but with
clock off. The register value can not be set correctly on some platform if
the clock is disabled. The pxa driver will check the value and report the
following warning:

------------[ cut here ]------------
WARNING: at drivers/tty/serial/pxa.c:545 serial_pxa_set_termios+0x1dc/0x250()
Modules linked in:
[] (unwind_backtrace+0x0/0xf0) from [] (warn_slowpath_common+0x4c/0x64)
[] (warn_slowpath_common+0x4c/0x64) from [] (warn_slowpath_null+0x18/0x1c)
[] (warn_slowpath_null+0x18/0x1c) from [] (serial_pxa_set_termios+0x1dc/0x250)
[] (serial_pxa_set_termios+0x1dc/0x250) from [] (uart_resume_port+0x128/0x2dc)
[] (uart_resume_port+0x128/0x2dc) from [] (serial_pxa_resume+0x18/0x24)
[] (serial_pxa_resume+0x18/0x24) from [] (platform_pm_resume+0x40/0x4c)
[] (platform_pm_resume+0x40/0x4c) from [] (pm_op+0x68/0xb4)
[] (pm_op+0x68/0xb4) from [] (device_resume+0xb0/0xec)
[] (device_resume+0xb0/0xec) from [] (dpm_resume+0xe0/0x194)
[] (dpm_resume+0xe0/0x194) from [] (dpm_resume_end+0xc/0x18)
[] (dpm_resume_end+0xc/0x18) from [] (suspend_devices_and_enter+0x16c/0x1ac)
[] (suspend_devices_and_enter+0x16c/0x1ac) from [] (enter_state+0xac/0xdc)
[] (enter_state+0xac/0xdc) from [] (state_store+0xa0/0xbc)
[] (state_store+0xa0/0xbc) from [] (kobj_attr_store+0x18/0x1c)
[] (kobj_attr_store+0x18/0x1c) from [] (sysfs_write_file+0x108/0x140)
[] (sysfs_write_file+0x108/0x140) from [] (vfs_write+0xac/0x134)
[] (vfs_write+0xac/0x134) from [] (sys_write+0x3c/0x68)
[] (sys_write+0x3c/0x68) from [] (ret_fast_syscall+0x0/0x2c)
---[ end trace 88289eceb4675b04 ]---

This patch fix the problem by adding the power on opertion back for uart
console when console_suspend_enabled is true.

Signed-off-by: Ning Jiang 
Tested-by: Mayank Rana 
Signed-off-by: Greg Kroah-Hartman

serial: pxa: work around for errata #20

2011-11-11T17:35:15+00:00

commit e44aabd649c80e8be16ede3ed3cbff6fb2561ca9 upstream.

Errata E20: UART: Character Timeout interrupt remains set under certain
software conditions.

Implication: The software servicing the UART can be trapped in an infinite loop.

Signed-off-by: Marcus Folkesson 
Signed-off-by: Greg Kroah-Hartman

cris: fix a build error in drivers/tty/serial/crisv10.c

2011-11-11T17:35:11+00:00

commit 2f7861de111bb8e33e6ab9f9607583c6fbc00132 upstream.

This patch fixes the following build error:

drivers/tty/serial/crisv10.c:4453: error: 'if_ser0' undeclared (first use in this function): 2 errors in 2 logs
        v3.1-rc4/cris/cris-allmodconfig v3.1-rc4/cris/cris-allyesconfig
drivers/tty/serial/crisv10.c:4453: error: (Each undeclared identifier is reported only once: 2 errors in 2 logs
        v3.1-rc4/cris/cris-allmodconfig v3.1-rc4/cris/cris-allyesconfig
drivers/tty/serial/crisv10.c:4453: error: for each function it appears in.): 2 errors in 2 logs
        v3.1-rc4/cris/cris-allmodconfig v3.1-rc4/cris/cris-allyesconfig

"if_ser0" is a typo, it should be "if_serial_0".

Cc: Mikael Starvik 
Cc: Jesper Nilsson 
Signed-off-by: WANG Cong 
Signed-off-by: Greg Kroah-Hartman

tty: Add "spi:" prefix for spi modalias

2011-10-03T18:39:49+00:00

commit 8c4074cd2254606aeb788d518ccc27c9f97129e1 upstream.

Since commit e0626e38 (spi: prefix modalias with "spi:"),
the spi modalias is prefixed with "spi:".

This patch adds "spi:" prefix and removes "-spi" suffix in the modalias.

Signed-off-by: Axel Lin 
Signed-off-by: Greg Kroah-Hartman

8250: Fix race condition in serial8250_backup_timeout().

2011-10-03T18:39:48+00:00

commit dbb3b1ca5609d1f3848cd387d06cc60aaacf7f98 upstream.

This is to fix an issue where output will suddenly become very slow.
The problem occurs on 8250 UARTS with the hardware bug UART_BUG_THRE.

BACKGROUND
For normal UARTs (without UART_BUG_THRE): When the serial core layer
gets new transmit data and the transmitter is idle, it buffers the
data and calls the 8250s' serial8250_start_tx() routine which will
simply enable the TX interrupt in the IER register and return. This
should immediately fire a THRE interrupt and begin transmitting the
data.
For buggy UARTs (with UART_BUG_THRE): merely enabling the TX interrupt
in IER does not necessarily generate a new THRE interrupt.
Therefore, a background timer periodically checks to see if there is
pending data, and starts transmission if that is the case.

The bug happens on SMP systems when the system has nothing to transmit,
the transmit interrupt is disabled and the following sequence occurs:
- CPU0: The background timer routine serial8250_backup_timeout()
  starts and saves the state of the interrupt enable register (IER)
  and then disables all interrupts in IER. NOTE: The transmit interrupt
  (TI) bit is saved as disabled.
- CPU1: The serial core gets data to transmit, grabs the port lock and
  calls serial8250_start_tx() which enables the TI in IER.
- CPU0: serial8250_backup_timeout() waits for the port lock.
- CPU1: finishes (with TI enabled) and releases the port lock.
- CPU0: serial8250_backup_timeout() calls the interrupt routine which
  will transmit the next fifo's worth of data and then restores the
  IER from the previously saved value (TI disabled).
At this point, as long as the serial core has more transmit data
buffered, it will not call serial8250_start_tx() again and the
background timer routine will slowly transmit the data.

The fix is to have serial8250_start_tx() get the port lock before
it saves the IER state and release it after restoring IER. This will
prevent serial8250_start_tx() from running in parallel.

Signed-off-by: Al Cooper 
Signed-off-by: Greg Kroah-Hartman

8250_pci: add support for Rosewill RC-305 4x serial port card

2011-10-03T18:39:48+00:00

commit 44178176ecc55ad370b837dd2c4b4b8bed1e3823 upstream.

This patch adds support for the Rosewill RC-305 four-port PCI serial
card, and probably any other four-port serial cards based on the
Moschip MCS9865 chip, assuming that the EEPROM on the card was
programmed in accordance with Table 6 of the MCS9865 EEPROM
Application Note version 0.3 dated 16-May-2008, available from the
Moschip web site (registration required).

This patch is based on an earlier patch [1] for the SYBA 6x serial
port card by Ira W. Snyder.

[1]: http://www.gossamer-threads.com/lists/linux/kernel/1162435

Signed-off-by: Eric Smith 
Signed-off-by: Greg Kroah-Hartman