Age | Commit message (Collapse) | Author |
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When serial-transmit a file from host to target, an error "BUG: scheduling
while atomic: cat/998/0x00010002" occurs.
BUG: scheduling while atomic: cat/998/0x00010002 Modules linked in:
Pid: 998, comm: cat
CPU: 0 Not tainted (3.0.15 #1)
PC is at n_tty_write+0x260/0x43c
LR is at tty_write_room+0x20/0x2c
pc : <80204700> lr : <80206194> psr: 60000013
sp : 863b9e78 ip : 8038e378 fp : 863b9ec4
r10: 00000fff r9 : 863b6400 r8 : 86165d80
r7 : 863b8000 r6 : 86368b6c r5 : 86368800 r4 : 00000002
r3 : 00000010 r2 : 00000000 r1 : 00000040 r0 : 00000002
Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
Control: 10c53c7d Table: 863f8059 DAC: 00000015 <80031f5c>
(show_regs+0x0/0x54) from <803761f0>
(__schedule_bug+0x4c/0x60)
r4:863b9e30 r3:60000193
<803761a4> (__schedule_bug+0x0/0x60) from <8037941c>
(__schedule+0x35c/0x3c4)
Thanks to Tadayoshi Arai <ara@lineo.co.jp> for reporting this and submitting
this patch
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Add hardware flow control support,
Add transmit DMA support,
Add FIFO operation support,
Add MSB/LSB on data support,
Add 9-bits MARK/SPACE support.
Signed-off-by: Jingchang Lu <b35083@freescale.com>
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Signed-off-by: Jingchang Lu <b35083@freescale.com>
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Signed-off-by: Jingchang Lu <b35083@freescale.com>
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Add basic UART and console support for MVF.
Signed-off-by: Jason Jin <Jason.jin@freescale.com>
Signed-off-by: Jingchang Lu <b35083@freescale.com>
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add dma header to fix the compiling error.
Signed-off-by: Huang Shijie <b32955@freescale.com>
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Remove linux/mm.h inclusion from netdevice.h -- it's unused (I've checked manually).
To prevent mm.h inclusion via other channels also extract "enum dma_data_direction"
definition into separate header. This tiny piece is what gluing netdevice.h with mm.h
via "netdevice.h => dmaengine.h => dma-mapping.h => scatterlist.h => mm.h".
Removal of mm.h from scatterlist.h was tried and was found not feasible
on most archs, so the link was cutoff earlier.
Hope people are OK with tiny include file.
Note, that mm_types.h is still dragged in, but it is a separate story.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The DMA RX thread may run on another CPU, while the application
runs on one CPU.
The application will close the uart when it finishes the required reading.
But the DMA RX thread maybe still running in this situation.
So add a wait queue to synchronize the __TWO__ sides in the SMP.
Signed-off-by: Huang Shijie <b32955@freescale.com>
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This reverts commit 7e5181cd28ac3d786d0760f405fa5a1e3407a7a9.
Signed-off-by: Huang Shijie <b32955@freescale.com>
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Allow UART to be a source from wakeup from low power mode.
Tested on a mx6sabrelite (where ttymxc1 is the console) by doing:
echo enabled > /sys/devices/platform/imx-uart.1/tty/ttymxc1/power/wakeup
echo mem > /sys/power/state
and then pressing a key in the console will wakeup the system.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
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Enlarge the RX FIFO threthold from 1 to 16 when the DMA is enabled.
This will give us better performance.
Signed-off-by: Huang Shijie <b32955@freescale.com>
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This reverts commit 6565023ad182d3347972aad3f1a13ba57266e81a.
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Allow UART to be a source for wakeup from low power mode.
Tested on a mx6sabrelite (where ttymxc1 is the console) by doing:
echo enabled > /sys/devices/platform/imx-uart.1/tty/ttymxc1/power/wakeup
echo mem > /sys/power/state
and then pressing a key in the console will wakeup the sytem.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
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The origin code did not check the running situation.
It will cause a NULL pointer issue.
This patch fixes it.
Signed-off-by: Huang Shijie <b32955@freescale.com>
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The original code will copy the upper layer's data to its
own buffer. But this is not necessary.
Map the upper layer's buffer directly to DMA's scatterlist.
This will enhance the performance of UART TX.
Signed-off-by: Huang Shijie <b32955@freescale.com>
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use the platformdata to fix the compiling error.
We save the DMA RX/TX request numbers in the platformdata.
Signed-off-by: Huang Shijie <b32955@freescale.com>
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The console feature's write routing is unsafe on SMP with
the startup/shutdown call. It happend to cause Android bootup
without shell runnable.
Actually on Android boot, there's 3 consumers of the console
* the kernel printk
* the init process using /dev/kmsg to call printk to show log
* shell, which open /dev/console and write with sys_write()
The shell goes into the normal uart open/write routing,
but the other two go into the console operations.
The open routing calls imx serial startup, which will write USR1/2
register without any lock and critical with imx_console_write call.
Here add spin_lock for startup/shutdown/console_write routing.
Remove the imx_setup_ufcr() call on startup when CONSOLE enabled,
as this will cause clock reinit, and output garbage.
Signed-off-by: Xinyu Chen <xinyu.chen@freescale.com>
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add the DMA support for the uart driver.
Signed-off-by: Huang Shijie <b32955@freescale.com>
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Modify uart driver to support DCE/DTE mode
Signed-off-by: Lionel Xu <Lionel.Xu@freescale.com>
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UART hold the following locks in order of:
imx_set_termios():
--> spin_lock_irqsave(&sport->port.lock, flags)
del_timer_sync(&sport->timer);
--> spin_lock(timer->base->lock);
--> spin_unlock(timer->base->lock);
spin_unlock_irqrestore(&sport->port.lock);
while when imx_timeout() may invoked in following stack:
run_timer_softirq():
--> spin_lock_irqsave(timer->base->lock, flags);
imx_timeout();
--> spin_lock_irqsave(&sport->port.lock, flags);
...;
--> spin_unlock_irqrestore(&sport->port.lock, flags);
spin_unlock_irqrestore(timer->base->lock, flags);
the above two cases hold lock with revert order, may
deadlock in SMP platform.
Signed-off-by: Zeng Zhaoming <b32542@freescale.com>
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1. Enable wake up of uart;
Signed-off-by: Anson Huang <b20788@freescale.com>
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Enable suspend/resume for MX6, using debug
UART as wake up source due to hardware design
limitation.
Signed-off-by: Anson Huang <b20788@freescale.com>
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Early uart has more than one contributors.
Remove "all right reserve" declare in source code.
Signed-off-by: Zeng Zhaoming <b32542@freescale.com>
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Add early uart support for i.MX platforms
Signed-off-by: Anson Huang <b20788@freescale.com>
Signed-off-by: Zeng Zhaoming <b32542@freescale.com>
Reviewed-by: Robby Cai <r63905@freescale.com>
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commit 0c73c08ec73dbe080b9ec56696ee21d32754d918 upstream.
For /dev/console case, we do not kill all ldisc users. It's due to
redirected_tty_write test in __tty_hangup. In that case there still
might be a process waiting e.g. in n_tty_read for input.
We wait for such processes to disappear. The problem is that we use a
timeout. After this timeout, we continue closing the ldisc and start
freeing tty resources. It obviously leads to crashes when the other
process is woken.
So to fix this, we wait infinitely before reiniting the ldisc. (The
tiocsetd remains untouched -- times out after 5s.)
This is nicely reproducible with this run from shell:
exec 0<>/dev/console 1<>/dev/console 2<>/dev/console
and stopping a getty like:
systemctl stop serial-getty@ttyS0.service
The crash proper may be produced only under load or with constified
timing the same as for 92f6fa09b.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Dave Young <hidave.darkstar@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Dmitriy Matrosov <sgf.dma@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit 300420722e0734a4254f3b634e0f82664495d210 upstream.
It is the only place where reinit is called from. And we really need
to wait for the old ldisc to go once. Actually this is the place where
the waiting originally was (before removed and re-added later).
This will make the fix in the following patch easier to implement.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Dave Young <hidave.darkstar@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Dmitriy Matrosov <sgf.dma@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit df92d0561de364de53c42abc5d43e04ab6f326a5 upstream.
To fix a nasty bug in ldisc hup vs. reinit we need to wait infinitely
long for ldisc to be gone. So here we add a parameter to
tty_ldisc_wait_idle to allow that.
This is only a preparation for the real fix which is done in the
following patches.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Dave Young <hidave.darkstar@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Dmitriy Matrosov <sgf.dma@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit c2a3e84f950e7ddba1f3914b005861d46ae60359 upstream.
Reading from the DCC grabs a character from the buffer and
clears the status bit. Since this is a context-changing
operation, instructions following the character read that rely on
the status bit being accurate need to be synchronized with an
ISB.
In this case, the status bit check needs to execute after the
character read otherwise we run the risk of reading the character
and checking the status bit before the read can clear the status
bit in the first place. When this happens, the user will see the
same character they typed twice, instead of once.
Add an ISB after the read and the write, so that the status check
is synchronized with the read/write operations.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit 8249f743f732ccbc3056428945ab1d9bd36d46bf upstream.
ML7831 is companion chip for Intel Atom E6xx series.
Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.lapis-semi.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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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 <tomoya.rohm@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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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 <tomoya-linux@dsn.lapis-semi.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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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 <cascardo@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit 94abc56f4d90f289ea32a0a11d3577fcd8cb28fb upstream.
The following patch removed uart_change_pm() in uart_resume_port():
commit 5933a161abcb8d83a2c145177f48027c3c0a8995
Author: Yin Kangkai <kangkai.yin@linux.intel.com>
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:
[<c0281f30>] (unwind_backtrace+0x0/0xf0) from [<c029341c>] (warn_slowpath_common+0x4c/0x64)
[<c029341c>] (warn_slowpath_common+0x4c/0x64) from [<c029344c>] (warn_slowpath_null+0x18/0x1c)
[<c029344c>] (warn_slowpath_null+0x18/0x1c) from [<c044b1e4>] (serial_pxa_set_termios+0x1dc/0x250)
[<c044b1e4>] (serial_pxa_set_termios+0x1dc/0x250) from [<c044a840>] (uart_resume_port+0x128/0x2dc)
[<c044a840>] (uart_resume_port+0x128/0x2dc) from [<c044bbe0>] (serial_pxa_resume+0x18/0x24)
[<c044bbe0>] (serial_pxa_resume+0x18/0x24) from [<c0454d34>] (platform_pm_resume+0x40/0x4c)
[<c0454d34>] (platform_pm_resume+0x40/0x4c) from [<c0457ebc>] (pm_op+0x68/0xb4)
[<c0457ebc>] (pm_op+0x68/0xb4) from [<c0458368>] (device_resume+0xb0/0xec)
[<c0458368>] (device_resume+0xb0/0xec) from [<c04584c8>] (dpm_resume+0xe0/0x194)
[<c04584c8>] (dpm_resume+0xe0/0x194) from [<c0458588>] (dpm_resume_end+0xc/0x18)
[<c0458588>] (dpm_resume_end+0xc/0x18) from [<c02c518c>] (suspend_devices_and_enter+0x16c/0x1ac)
[<c02c518c>] (suspend_devices_and_enter+0x16c/0x1ac) from [<c02c5278>] (enter_state+0xac/0xdc)
[<c02c5278>] (enter_state+0xac/0xdc) from [<c02c48ec>] (state_store+0xa0/0xbc)
[<c02c48ec>] (state_store+0xa0/0xbc) from [<c0408f7c>] (kobj_attr_store+0x18/0x1c)
[<c0408f7c>] (kobj_attr_store+0x18/0x1c) from [<c034a6a4>] (sysfs_write_file+0x108/0x140)
[<c034a6a4>] (sysfs_write_file+0x108/0x140) from [<c02fb798>] (vfs_write+0xac/0x134)
[<c02fb798>] (vfs_write+0xac/0x134) from [<c02fb8cc>] (sys_write+0x3c/0x68)
[<c02fb8cc>] (sys_write+0x3c/0x68) from [<c027c700>] (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 <ning.jiang@marvell.com>
Tested-by: Mayank Rana <mrana@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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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 <marcus.folkesson@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit 1177c0efc04d032644895b8d757f55b433912596 upstream.
Mistakenly, commit 64ba3dc3143d (tty: never hold BTM while getting
tty_mutex) switched one fail path in ptmx_open to not free the newly
allocated tty.
Fix that by jumping to the appropriate place. And rename the labels so
that it's clear what is going on there.
Introduced-in: v2.6.36-rc2
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit fa90e1c935472281de314e6d7c9a37db9cbc2e4e upstream.
If tty_add_file fails at the point it is now, we have to revert all
the changes we did to the tty. It means either decrease all refcounts
if this was a tty reopen or delete the tty if it was newly allocated.
There was a try to fix this in v3.0-rc2 using tty_release in 0259894c7
(TTY: fix fail path in tty_open). But instead it introduced a NULL
dereference. It's because tty_release dereferences
filp->private_data, but that one is set even in our tty_add_file. And
when tty_add_file fails, it's still NULL/garbage. Hence tty_release
cannot be called there.
To circumvent the original leak (and the current NULL deref) we split
tty_add_file into two functions, making the latter non-failing. In
that case we may do the former early in open, where handling failures
is easy. The latter stays as it is now. So there is no change in
functionality.
The original bug (leak) was introduced by f573bd176 (tty: Remove
__GFP_NOFAIL from tty_add_file()). Thanks Dan for reporting this.
Later, we may split tty_release into more functions and call only some
of them in this fail path instead. (If at all possible.)
Introduced-in: v2.6.37-rc2
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit c290f8358acaeffd8e0c551ddcc24d1206143376 upstream.
When tty_driver_lookup_tty fails in tty_open, we forget to drop a
reference to the tty driver. This was added by commit 4a2b5fddd5 (Move
tty lookup/reopen to caller).
Fix that by adding tty_driver_kref_put to the fail path.
I will refactor the code later. This is for the ease of backporting to
stable.
Introduced-in: v2.6.28-rc2
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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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 <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit 24d406a6bf736f7aebdc8fa0f0ec86e0890c6d24 upstream.
tty_operations->remove is normally called like:
queue_release_one_tty
->tty_shutdown
->tty_driver_remove_tty
->tty_operations->remove
However tty_shutdown() is called from queue_release_one_tty() only if
tty_operations->shutdown is NULL. But for pty, it is not.
pty_unix98_shutdown() is used there as ->shutdown.
So tty_operations->remove of pty (i.e. pty_unix98_remove()) is never
called. This results in invalid pty_count. I.e. what can be seen in
/proc/sys/kernel/pty/nr.
I see this was already reported at:
https://lkml.org/lkml/2009/11/5/370
But it was not fixed since then.
This patch is kind of a hackish way. The problem lies in ->install. We
allocate there another tty (so-called tty->link). So ->install is
called once, but ->remove twice, for both tty and tty->link. The fix
here is to count both tty and tty->link and divide the count by 2 for
user.
And to have ->remove called, let's make tty_driver_remove_tty() global
and call that from pty_unix98_shutdown() (tty_operations->shutdown).
While at it, let's document that when ->shutdown is defined,
tty_shutdown() is not called.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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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 <axel.lin@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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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 <alcooperx@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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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 <eric@brouhaha.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit ab8ba3a2d2cba6a658ef596cd5b2e0905b6c8a9f upstream.
It would have been nice if Intermec had supplied a PNP0501 _CID for the
COM3 device, but they didn't, so we have to recognize it explicitly.
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=40612
CC: Jeff Chua <jeff.chua.linux@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit b280a97d1caf6fe1d38b51ebb31219391f5ad1a0 upstream.
Fixes logic bug that software flow control cannot be disabled, because
serial_omap_configure_xonxoff() is not called if both IXON and IXOFF bits
are cleared.
Signed-off-by: Nick Pelly <npelly@google.com>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Tested-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit 8c2381af0d3ef62a681dac5a141b6dabb27bf2e1 upstream.
Currently, the hvc_console_print() function drops console output if the
hvc backend's put_chars() returns 0. This patch changes this behavior
to allow a retry through returning -EAGAIN.
This change also affects the hvc_push() function. Both functions are
changed to handle -EAGAIN and to retry the put_chars() operation.
If a hvc backend returns -EAGAIN, the retry handling differs:
- hvc_console_print() spins to write the complete console output.
- hvc_push() behaves the same way as for returning 0.
Now hvc backends can indirectly control the way how console output is
handled through the hvc console layer.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit f2eb3cdf14457fccb14ae8c4d7d7cee088cd3957 upstream.
Kconfig allows enabling console support for the SC26xx driver even when
it's configured as a module resulting in a:
ERROR: "uart_console_device" [drivers/tty/serial/sc26xx.ko] undefined!
modpost error since the driver was merged in
eea63e0e8a60d00485b47fb6e75d9aa2566b989b [SC26XX: New serial driver for
SC2681 uarts] in 2.6.25. Fixed by only allowing console support to be
enabled if the driver is builtin.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit 5568181f188ae9485a0cdbea5ea48f63d186a298 upstream.
Commit 4539c24fe4f92c09ee668ef959d3e8180df619b9 "tty/serial: Add
explicit PORT_TEGRA type" introduced separate flags describing the need
for IER bits UUE and RTOIE. Both bits are required for the XSCALE port
type. While that patch updated uart_config[] as required, the auto-probing
code wasn't updated to set the RTOIE flag when an XSCALE port type was
detected. This caused such ports to stop working. This patch rectifies
that.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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commit f086ced17191fa0c5712539d2b680eae3dc972a1 upstream.
FCS could be GSM0_SOF, so will break state machine...
[This byte isn't quoted in any way so a SOF here doesn't imply an error
occurred.]
Signed-off-by: Alek Du <alek.du@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
[Trivial but best backported once its in 3.1rc I think]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/arm/linux-2.6-arm-soc
* 'at91/fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/linux-2.6-arm-soc:
AT91: Change nand buswidth logic to match hardware default configuration
at91: Use "pclk" as con_id on at91cap9 and at91rm9200
at91: fix udc, ehci and mmc clock device name for cap9/9g45/9rl
atmel_serial: fix internal port num
at91: fix at91_set_serial_console: use platform device id
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6
* 'tty-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6:
serial: bcm63xx_uart: fix irq storm after rx fifo overrun.
amba pl011: platform data for reg lockup and glitch v2
amba pl011: workaround for uart registers lockup
tty: n_gsm: improper skb_pull() use was leaking framed data
tty: n_gsm: Fixed logic to decode break signal from modem status
TTY: ntty, add one more sanity check
TTY: ldisc, do not close until there are readers
8250: Fix capabilities when changing the port type
8250_pci: Fix missing const from merges
ARM: SAMSUNG: serial: Fix on handling of one clock source for UART
serial: ioremap warning fix for jsm driver.
8250_pci: add -ENODEV code for Intel EG20T PCH
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