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: Luis Henriques <luis.henriques@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Storing one struct per known board would be overkill. Pre-cast the
driver_data pointer to an unsigned long to avoid the pointer to int
compiler warning:
drivers/tty/serial/pch_uart.c:431:10: warning: cast from pointer to
integer of different size [-Wpointer-to-int-cast]
Unify the signed-ness of the baud and uartclk types throughout the
driver.
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The dmi_table is best accessed from the probe function, which is not
an __init function. Drop the __initdata annotation from the dmi_table
to avoid the section mismatch compiler warnings:
WARNING: drivers/tty/serial/pch_uart.o(.text+0x4871): Section mismatch
in reference from the function pch_uart_init_port() to the variable
.init.data:pch_uart_dmi_table
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use the DMI interface rather than manually matching DMI strings.
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Cc: Michael Brunner <mibru@gmx.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use DMI_BOARD_NAME to determine if we are running on a MinnowBoard and
set the uart clock to 50MHz if so. This removes the need to pass the
user_uartclk to the kernel at boot time.
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Waskiewicz <peter.p.waskiewicz.jr@intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Implement console poll for pch_uart, this could enable KGDBoC when
on pch-uart console.
Signed-off-by: Liang Li <liang.li@windriver.com>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When PCH_UART_CONSOLE and SERIAL_CORE_CONSOLE is not set neither, the
uart_port will have no 'sysrq' member hence their will need a '#ifdef'
in pch_uart.c to handle the case, otherwise we'll see compile error
like this:
CC [M] drivers/tty/serial/pch_uart.o
drivers/tty/serial/pch_uart.c: In function 'pch_uart_hal_read':
drivers/tty/serial/pch_uart.c:572:11: error: 'struct uart_port' has no member named 'sysrq'
make[4]: *** [drivers/tty/serial/pch_uart.o] Error 1
Reported-by: Randy Dunlap <rdunlap@infradead.org>
CC: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Liang Li <liang.li@windriver.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When send break to the uart port, we always get 'frame error', but we
can not just reset receive fifo in such case, otherwise the sysrq cmd
will not be received correctly.
When we handle sysrq output via pch_console_write, the priv lock has
already been taken so no need to take the lock in pch_console_write.
Signed-off-by: Liang Li <liang.li@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When we use pch_uart as system console like 'console=ttyPCH0,115200',
then 'send break' to it. We'll encounter the deadlock on a cpu/core,
with interrupts disabled on the core. When we happen to have all irqs
affinity to cpu0 then the deadlock on cpu0 actually deadlock whole
system.
In pch_uart_interrupt, we have spin_lock_irqsave(&priv->lock, flags)
then call pch_uart_err_ir when break is received. Then the call to
dev_err would actually call to pch_console_write then we'll run into
another spin_lock(&priv->lock), with interrupts disabled.
So in the call sequence lead by pch_uart_interrupt, we should be
carefully to call functions that will 'print message to console' only
in case the uart port is not being used as serial console.
Signed-off-by: Liang Li <liang.li@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.
Now, the one where most of tty_port_tty_get gets removed:
tty_flip_buffer_push.
IOW we also closed all the races in drivers not using tty_port_tty_get
at all yet.
Also we move tty_flip_buffer_push declaration from include/linux/tty.h
to include/linux/tty_flip.h to all others while we are changing it
anyway.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.
tty_insert_flip_string this time.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty pointer in
many call sites. Only tty_port will be needed and hence no more
tty_port_tty_get calls in those paths.
Here we start with tty_buffer_request_room.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CONFIG_HOTPLUG is going away as an option so __devinit is no longer
needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Lucas Tavares <lucaskt@linux.vnet.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CONFIG_HOTPLUG is going away as an option so __devexit_p is no longer
needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Lucas Tavares <lucaskt@linux.vnet.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reported by coccinelle:
drivers/tty/serial/pch_uart.c:979:1-14: alloc with no test, possible model on line 994
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Parity Setting value is reverse.
E.G. In case of setting ODD parity, EVEN value is set.
This patch inverts "if" condition.
Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rx Error interrupt(E.G. parity error) is not enabled.
So, when parity error occurs, error interrupt is not occurred.
As a result, the received data is not dropped.
This patch adds enable/disable rx error interrupt code.
Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Otherwise we fall back to the wrong value.
Reported-by: <dcb314@hotmail.com>
Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=44091
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pch_uart_interrupt() takes priv->port.lock which leads to two recursive
spinlock calls if low_latency==1 or CONFIG_PREEMPT_RT_FULL=y (one
otherwise):
pch_uart_interrupt
spin_lock_irqsave(priv->port.lock, flags)
case PCH_UART_IID_RDR_TO (data ready)
handle_rx_to
push_rx
tty_port_tty_get
spin_lock_irqsave(&port->lock, flags) <--- already hold this lock
...
tty_flip_buffer_push
...
flush_to_ldisc
spin_lock_irqsave(&tty->buf.lock)
spin_lock_irqsave(&tty->buf.lock)
disc->ops->receive_buf(tty, char_buf)
n_tty_receive_buf
tty->ops->flush_chars()
uart_flush_chars
uart_start
spin_lock_irqsave(&port->lock) <--- already hold this lock
Avoid this by using a dedicated lock to protect the eg20t_port structure
and IO access to its membase. This is more consistent with the 8250
driver. Ensure priv->lock is always take prior to priv->port.lock when
taken at the same time.
V2: Remove inadvertent whitespace change.
V3: Account for oops_in_progress for the private lock in
pch_console_write().
Note: Like the 8250 driver, if a printk is introduced anywhere inside
the pch_console_write() critical section, the kernel will hang
on a recursive spinlock on the private lock. The oops case is
handled by using a trylock in the oops_in_progress case.
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alexander Stein <alexander.stein@systec-electronic.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This driver anticipates pch_uart_verify_port() is not called
during installation.
However, actually pch_uart_verify_port() is called during
installation.
As a result, memory access violation occurs like below.
0. initial value: use_dma=0
1. starup()
- dma channel is not allocated because use_dma=0
2. pch_uart_verify_port()
- Set use_dma=1
3. UART processing acts DMA mode because use_dma=1
- memory access violation occurs!
This patch fixes the issue.
Solution:
Whenever pch_uart_verify_port() is called and then
dma channel is not allocated, the channel should be allocated.
Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Here are some tty and serial fixes for 3.4-rc2.
Most important here is the pl011 fix, which has been reported by about
100 different people, which means more people use it than I expected :)
There are also some 8250 driver reverts due to some problems reported by
them. And other minor fixes as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-3.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty and serial fixes from Greg KH:
"Here are some tty and serial fixes for 3.4-rc2.
Most important here is the pl011 fix, which has been reported by about
100 different people, which means more people use it than I expected
:)
There are also some 8250 driver reverts due to some problems reported
by them. And other minor fixes as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"
* tag 'tty-3.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
pch_uart: Add Kontron COMe-mTT10 uart clock quirk
pch_uart: Fix MSI setting issue
serial/8250_pci: add a "force background timer" flag and use it for the "kt" serial port
Revert "serial/8250_pci: setup-quirk workaround for the kt serial controller"
Revert "serial/8250_pci: init-quirk msi support for kt serial controller"
tty/serial/omap: console can only be built-in
serial: samsung: fix omission initialize ulcon in reset port fn()
printk(): add KERN_CONT where needed in hpet and vt code
tty/serial: atmel_serial: fix RS485 half-duplex problem
tty: serial: altera_uart: Check for NULL platform_data in probe.
isdn/gigaset: use gig_dbg() for debugging output
omap-serial: Fix the error handling in the omap_serial probe
serial: PL011: move interrupt clearing
Currently, occurring line status interrupt,
returned value is not set in interrupt handler function.
As a result, 0 can be returned.
This patch adds setting returned value.
Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
%02x format is easier to understand better than %d.
Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Target uart register access size is 8bit.
However, 32bit is used at 2 points.
This patch modifies type "unsigned int" to "unsigned char".
Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add UART clock quirk for the Kontron COMe-mTT10 module.
The board has previously been called nanoETXexpress-TT, therefore this
is also checked.
As suggested by Darren Hart the comparison in this patch version is
placed after the FRI2 checks to ensure it will also work with possible
upcoming changes to the FRI2 firmware.
This patch follows the patchset submitted by Darren Hart at
commit a46f5533ec.
Signed-off-by: Michael Brunner <mibru@gmx.de>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The following patch (MSI setting) is not enough.
commit e463595fd9
Author: Alexander Stein <alexander.stein@systec-electronic.com>
Date: Mon Jul 4 08:58:31 2011 +0200
pch_uart: Add MSI support
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
To enable MSI mode, PCI bus-mastering must be enabled.
This patch enables the setting.
cc: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge batch of fixes from Andrew Morton:
"The simple_open() cleanup was held back while I wanted for laggards to
merge things.
I still need to send a few checkpoint/restore patches. I've been
wobbly about merging them because I'm wobbly about the overall
prospects for success of the project. But after speaking with Pavel
at the LSF conference, it sounds like they're further toward
completion than I feared - apparently davem is at the "has stopped
complaining" stage regarding the net changes. So I need to go back
and re-review those patchs and their (lengthy) discussion."
* emailed from Andrew Morton <akpm@linux-foundation.org>: (16 patches)
memcg swap: use mem_cgroup_uncharge_swap fix
backlight: add driver for DA9052/53 PMIC v1
C6X: use set_current_blocked() and block_sigmask()
MAINTAINERS: add entry for sparse checker
MAINTAINERS: fix REMOTEPROC F: typo
alpha: use set_current_blocked() and block_sigmask()
simple_open: automatically convert to simple_open()
scripts/coccinelle/api/simple_open.cocci: semantic patch for simple_open()
libfs: add simple_open()
hugetlbfs: remove unregister_filesystem() when initializing module
drivers/rtc/rtc-88pm860x.c: fix rtc irq enable callback
fs/xattr.c:setxattr(): improve handling of allocation failures
fs/xattr.c:listxattr(): fall back to vmalloc() if kmalloc() failed
fs/xattr.c: suppress page allocation failure warnings from sys_listxattr()
sysrq: use SEND_SIG_FORCED instead of force_sig()
proc: fix mount -t proc -o AAA
Many users of debugfs copy the implementation of default_open() when
they want to support a custom read/write function op. This leads to a
proliferation of the default_open() implementation across the entire
tree.
Now that the common implementation has been consolidated into libfs we
can replace all the users of this function with simple_open().
This replacement was done with the following semantic patch:
<smpl>
@ open @
identifier open_f != simple_open;
identifier i, f;
@@
-int open_f(struct inode *i, struct file *f)
-{
(
-if (i->i_private)
-f->private_data = i->i_private;
|
-f->private_data = i->i_private;
)
-return 0;
-}
@ has_open depends on open @
identifier fops;
identifier open.open_f;
@@
struct file_operations fops = {
...
-.open = open_f,
+.open = simple_open,
...
};
</smpl>
[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull slave-dmaengine update from Vinod Koul:
"This includes the cookie cleanup by Russell, the addition of context
parameter for dmaengine APIs, more arm dmaengine driver cleanup by
moving code to dmaengine, this time for imx by Javier and pl330 by
Boojin along with the usual driver fixes."
Fix up some fairly trivial conflicts with various other cleanups.
* 'next' of git://git.infradead.org/users/vkoul/slave-dma: (67 commits)
dmaengine: imx: fix the build failure on x86_64
dmaengine: i.MX: Fix merge of cookie branch.
dmaengine: i.MX: Add support for interleaved transfers.
dmaengine: imx-dma: use 'dev_dbg' and 'dev_warn' for messages.
dmaengine: imx-dma: remove 'imx_dmav1_baseaddr' and 'dma_clk'.
dmaengine: imx-dma: remove unused arg of imxdma_sg_next.
dmaengine: imx-dma: remove internal structure.
dmaengine: imx-dma: remove 'resbytes' field of 'internal' structure.
dmaengine: imx-dma: remove 'in_use' field of 'internal' structure.
dmaengine: imx-dma: remove sg member from internal structure.
dmaengine: imx-dma: remove 'imxdma_setup_sg_hw' function.
dmaengine: imx-dma: remove 'imxdma_config_channel_hw' function.
dmaengine: imx-dma: remove 'imxdma_setup_mem2mem_hw' function.
dmaengine: imx-dma: remove dma_mode member of internal structure.
dmaengine: imx-dma: remove data member from internal structure.
dmaengine: imx-dma: merge old dma-v1.c with imx-dma.c
dmaengine: at_hdmac: add slave config operation
dmaengine: add context parameter to prep_slave_sg and prep_dma_cyclic
dmaengine/dma_slave: introduce inline wrappers
dma: imx-sdma: Treat firmware messages as warnings instead of erros
...
Add inline wrappers for device_prep_slave_sg() and device_prep_dma_cyclic()
interfaces to hide new parameter from current users of affected interfaces.
Convert current users to use new wrappers instead of direct calls.
Suggested by Russell King [https://lkml.org/lkml/2012/2/3/269].
Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
Rather than hardcode 9600, use the existing default_baud parameter (which
also defaults to 9600).
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For cases where boards with non-default clocks are not yet added to the kernel
or when the clock varies across hardware revisions, it is useful to be
able to specify the UART clock on the kernel command line.
Add the user_uartclk parameter and prefer it, if set, to the default and
board specific UART clock settings. Specify user_uartclock on the command-line
with "pch_uart.user_uartclk=48000000".
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for the Fish River Island II (FRI2) UART clock following the CM-iTC
quirk handling mechanism. Depending on the firmware installed on the device, the
FRI2 uses a 48MHz or a 64MHz UART clock. This is detected with DMI strings.
Add similar UART clock quirk handling to the pch_console_setup() function to
enable kernel messages on boards with non-standard UART clocks.
Per Alan's suggestion, abstract out UART clock selection into
pch_uart_get_uartclk() to avoid code duplication.
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The term "base baud" refers to the fastest baud rate the device can communicate
at. This is clock/16. pch_uart is using base_baud as the clock itself. Rename
the variables to be semantically correct.
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pch_uart_hal_request() has parameters which it never uses, also
it is very short, so merge it with its caller to make code cleaner.
No functional changes at all.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The short get_msr() has some unnecessary code and only used once,
so merge it with its caller to make code cleaner. No functional
change at all.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This driver will be use as interfaces for multiple kinds of
devices like Bluetooth/GPS etc, this debug hook will make driver
debugging much easier.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add console support to pch_uart. To enable append e.g.
console=ttyPCH0,115200 to your kernel command line.
This is not expected work on CM-iTC boards due to their having a different
clock.
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
On October 1 in 2011,
OKI SEMICONDUCTOR Co., Ltd. changed the company name in to LAPIS Semiconductor Co., Ltd.
Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.lapis-semi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
