The virtual console has (undocumented) module parameters to set the
colors for italic and underlined text, but the default text color was
hardcoded for some reason. This made it impossible to change the color
for startup messages, or to set the default for new virtual consoles.
Add a module parameter for that, and document the entire bunch.
Any hacker who thinks that a command prompt on a "black screen with
white font" is not supicious enough can now use the kernel parameter
vt.color=10 to get a nice, evil green.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The MXS_AUART_DMA_CONFIG is originally used to check if the DT node
is configured with the DMA property.
But now, the MXS_AUART_DMA_CONFIG is set unconditionally in the
serial_mxs_probe_dt(), so the check in the mxs_auart_settermios() is
not necessary anymore. This patch removes this macro.
Signed-off-by: Huang Shijie <shijie8@gmail.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The original DMA support works only when RTS/CTS is enabled.
(see the "e800163 serial: mxs-auart: add the DMA support for mx28")
But after several patches, DMA support has lost this limit.
(see the "bcc20f9 serial: mxs-auart: move to use generic DMA helper")
So an UART without the RTS/CTS lines may also enables the DMA support,
in which case the UART may gets unpredictable results.
This patch adds an optional property for the UART DT node
which indicates the UART has RTS and CTS lines, and it also means you
enable the DMA support for this UART.
This patch also adds a macro MXS_AUART_RTSCTS, and uses it to check
RTS/CTS before we enable the DMA for the UART.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Huang Shijie <shijie8@gmail.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fixes a below warning reported by kbuild test robot.
drivers/tty/serial/st-asc.c:727:28: warning: 'asc_match' defined but
not used [-Wunused-variable]
The code used in DT case is now ifdefed under CONFIG_OF to fix this
warning.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Reported-by: Kbuild Test Robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 85c9969074.
Alexander wishes to remove this patch as it is incorrect.
Reported-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, Rx error handling only triggers if there is some Rx data.
Fix that by checking for error - before the data handling.
Reported-by: Mischa Jonker <mjonker@synopsys.com>
Tested-by: Mischa Jonker <mjonker@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instrumented testing shows a tty can be hungup multiple times [1].
Although concurrent hangups are properly serialized, multiple
hangups for the same tty should be prevented.
If tty has already been HUPPED, abort hangup. Note it is not
necessary to cleanup file *redirect on subsequent hangups,
as only TIOCCONS can set that value and ioctls are disabled
after hangup.
[1]
Test performed by simulating a concurrent async hangup via
tty_hangup() with a sync hangup via tty_vhangup(), while
__tty_hangup() was instrumented with:
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 26bb78c..fe8b061 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -629,6 +629,8 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session)
tty_lock(tty);
+ WARN_ON(test_bit(TTY_HUPPED, &tty->flags));
+
/* some functions below drop BTM, so we need this bit */
set_bit(TTY_HUPPING, &tty->flags);
Test result:
WARNING: at /home/peter/src/kernels/mainline/drivers/tty/tty_io.c:632 __tty_hangup+0x459/0x460()
Modules linked in: ip6table_filter ip6_tables ebtable_nat <...snip...>
CPU: 6 PID: 1197 Comm: kworker/6:2 Not tainted 3.10.0-0+rfcomm-xeon #0+rfcomm
Hardware name: Dell Inc. Precision WorkStation T5400 /0RW203, BIOS A11 04/30/2012
Workqueue: events do_tty_hangup
0000000000000009 ffff8802b16d7d18 ffffffff816b553e ffff8802b16d7d58
ffffffff810407e0 ffff880254f95c00 ffff880254f95c00 ffff8802bfd92b00
ffff8802bfd96b00 ffff880254f95e40 0000000000000180 ffff8802b16d7d68
Call Trace:
[<ffffffff816b553e>] dump_stack+0x19/0x1b
[<ffffffff810407e0>] warn_slowpath_common+0x70/0xa0
[<ffffffff8104082a>] warn_slowpath_null+0x1a/0x20
[<ffffffff813fb279>] __tty_hangup+0x459/0x460
[<ffffffff8107409c>] ? finish_task_switch+0xbc/0xe0
[<ffffffff813fb297>] do_tty_hangup+0x17/0x20
[<ffffffff8105fd6f>] process_one_work+0x16f/0x450
[<ffffffff8106007c>] process_scheduled_works+0x2c/0x40
[<ffffffff8106060a>] worker_thread+0x26a/0x380
[<ffffffff810603a0>] ? rescuer_thread+0x310/0x310
[<ffffffff810698a0>] kthread+0xc0/0xd0
[<ffffffff816b0000>] ? destroy_compound_page+0x65/0x92
[<ffffffff810697e0>] ? kthread_create_on_node+0x130/0x130
[<ffffffff816c495c>] ret_from_fork+0x7c/0xb0
[<ffffffff810697e0>] ? kthread_create_on_node+0x130/0x130
---[ end trace 98d9f01536cf411e ]---
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add DT support to the SCCNCP serial driver.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch replaces switch in probe function to constant structure
for each supported IC. This makes code a bit smaller and cleaner and
helps adding DT support to the driver in the future.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch removes "frequency" parameter from SCCNXP platform_data
and uses CLK API for getting clock. If CLK ommited, default IC
frequency will be used instead.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The patch disables the regulator in case of errors, if we have it.
In addition, the patch adds support for deferred regulator probe and
makes error path are a bit clean.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pdev->id is not a valid choice for device-tree probed devices. So use
the (properly determined) line from efm32_uart_probe consistenly
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We can't use dev->mod_index for selecting the interrupt routing entry,
because it's not an index into interrupt routing table. It will be even
wrong on a machine with 2 CPUs (4 cores). But all needed information is
contained in the PAT entries for the serial ports. mod[0] contains the
iosapic address and mod_info has some indications for the interrupt
input (at least it looks like it). This patch implements the searching
for the right iosapic and uses this interrupt input information.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: <stable@vger.kernel.org> # 3.10
Signed-off-by: Helge Deller <deller@gmx.de>
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>
Because the UART lack of receive timeout register, so we use a timer to trigger
data receive.
The DBGU is regarded as UART.
Signed-off-by: Elen Song <elen.song@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Distinguish usart and uart by read ip name register,
The usart read name is "USAR",
The uart and dbgu read name is "DBGU".
Signed-off-by: Elen Song <elen.song@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We will switch to pio mode when request of dma or pdc fail.
But soon or later, when the request is success, the transfer mode can switch to them at
next open serial port action.
So in startup stage, we should get original transfer mode.
Signed-off-by: Elen Song <elen.song@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Request a cyclic dma channel for rx dma use. Use cyclic transfer is to prevent
receive data overrun.
We allocate a cycle dma cookie after request channel,
after that, enable uart timeout interrupt in startup stage, when data successful
received, the timeout callback will check the residual bytes and insert
receiving datas into the framework during the transfer interval.
When current descriptor finished, the dma callback will also check the residual
bytes and filp the receiving data.
Signed-off-by: Elen Song <elen.song@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Request a slave dma channel for tx dma use. Tx dma will setup a single transfer,
when transfer complete, it will call atmel_complete_tx_dma to do finish stuff.
Signed-off-by: Elen Song <elen.song@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
use function pointer can avoid define atmel_use_pdc_tx/rx everywhere.
(*prepare_rx/tx)() is in setup transfer stage.
(*schedule_rx/tx)() is in tasklet schedule stage.
(*release_rx/tx)() is used when shutdown the transfer.
Signed-off-by: Elen Song <elen.song@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The DMA is available since at91sam9x5 socs, before that, we use PDC.
Signed-off-by: Elen Song <elen.song@atmel.com>
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>
Found with coccinelle, manually fixed and verified.
Signed-off-by: Alexandru Juncu <alexj@rosedu.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fixes wrong dev_pm_ops which caused by commit:
serial: max310x: Driver rework.
CC drivers/tty/serial/max310x.o
LD drivers/video/fb.o
CC drivers/w1/slaves/w1_ds2433.o
CC drivers/w1/slaves/w1_ds2760.o
CC drivers/xen/balloon.o
CC drivers/video/backlight/adp8870_bl.o
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.suspend') [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.resume') [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.freeze') [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.thaw') [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.poweroff') [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/max310x.c:1292:8: warning: (near initialization for 'max310x_pm_ops.restore') [enabled by default]
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Platform drivers use "platform:" prefix in module alias.
Also use DRIVER_NAME in MODULE_ALIAS to make module autoloading work.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function tty_port_tty_hangup() could leak a reference to the tty_struct:
struct tty_struct *tty = tty_port_tty_get(port);
if (tty && (!check_clocal || !C_CLOCAL(tty))) {
tty_hangup(tty);
tty_kref_put(tty);
}
If tty != NULL and the second condition is false we never call tty_kref_put and
the reference is leaked.
Fix by always calling tty_kref_put() which accepts a NULL argument.
The patch fixes a regression introduced by commit aa27a094.
Acked-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Gianluca Anzolin <gianluca@sottospazio.it>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org> # 3.10
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Without this patch the driver waits ~1 ms for the UART to become idle. At
115200n8 this time is (theoretically) enough to transfer 11.5 characters
(= 115200 bits/s / (10 Bits/char) * 1ms). As the mxs-auart has a fifo size
of 16 characters the clock is gated too early. The problem is worse for
lower baud rates.
This only happens to really shut down the transmitter in the middle of a
transfer if /dev/ttyAPPx isn't opened in userspace (e.g. by a getty) but
was at least once (because the bootloader doesn't disable the transmitter).
So increase the timeout to 20 ms which should be enough for 9600n8, too.
Moreover skip gating the clock if the timeout is elapsed.
Cc: stable@vger.kernel.org # v2.6.39+
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The handler needs to ack the pending events before actually handling them.
Otherwise a new event might come in after it it considered non-pending or
handled and is acked then without being handled. So this event is only
noticed when the next interrupt happens.
Without this patch an i.MX28 based machine running an rt-patched kernel
regularly hangs during boot.
Cc: stable@vger.kernel.org # v2.6.39+
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Replace kzalloc and clk_get by their managed counterparts to simplify
error and cleanup paths.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-> The ledptrs[] array is never initialized.
-> There is no place where kbd->ledmode is set to LED_SHOW_MEM therefore the if
statement does not make much sense.
-> Since LED_SHOW_MEM is not used, it can be removed from the header file as well.
Signed-off-by: Andreas Platschek <andi.platschek@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
UARTDM cores have a TX fifo that can accept more than one
character per register write, but the msm_serial driver currently
only supports 1 character mode. Add support for this mode of operation
to speed up the transmit path on DM devices.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently msm_set_baud_rate() assumes the uart clock rate is
1.8432 MHz. This is not always true, and limits our options to
program the baud rate. Instead of assuming the rate and
hard-coding the baud_code based on it, calculate the divider that
we want and try to find the closest baud_code that matches. This
allows us to support uarts with faster clock speeds.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/serial/msm_serial.c:302:6: warning: symbol 'msm_set_mctrl' was
not declared. Should it be static?
drivers/tty/serial/msm_serial.c:597:17: warning: incorrect type in argument 2
(different address spaces)
drivers/tty/serial/msm_serial.c:597:17: expected void volatile [noderef] <asn:2>*addr
drivers/tty/serial/msm_serial.c:597:17: got unsigned int *
drivers/tty/serial/msm_serial.c:608:33: warning: incorrect type in argument 1
(different address spaces)
drivers/tty/serial/msm_serial.c:608:33: expected void volatile [noderef] <asn:2>*addr
drivers/tty/serial/msm_serial.c:608:33: got unsigned int *gsbi_base
drivers/tty/serial/msm_serial.c:648:37: warning: incorrect type in assignment
(different address spaces)
drivers/tty/serial/msm_serial.c:648:37: expected unsigned int *gsbi_base
drivers/tty/serial/msm_serial.c:648:37: got void [noderef] <asn:2>*
Mark the ioremapped memory as __iomem and use writel instead of
iowrite because we're not dealing with PCI devices. Also, mark
msm_set_mctrl() static because it isn't used outside this file.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
UARTDM serial devices require us to wait for the entire TX fifo
to drain before we can change the contents of the NCF_TX
register. Furthermore, if we write any characters to the TX fifo
within the same clock cycle of changing the NCF_TX register the
NCF_TX register won't latch properly.
To fix these issues we should read back the NCF_TX register to
delay any TX fifo accesses by a clock cycle and we should wait
for the TX fifo to drain (instead of just waiting for the fifo to
be ready to receive more characters). Failure to do so leads to
random NUL bytes interspersed in the output.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The quirks and PCI ID table entries for the original ADDI-DATA APCI-7800
(not the newer APCI-7800-3) use PCI_DEVICE_ID_ADDIDATA_APCI7800 from
<linux/pci_ids.h> but the device ID was actually assigned to ADDI-DATA
by Applied Micro Circuits Corporation (PCI_VENDOR_ID_AMCC). Replace it
locally with #define PCI_DEVICE_ID_AMCC_ADDIDATA_APCI7800.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PCI_VENDOR_ID_ADDIDATA_OLD has the same value (0x10e8) as
PCI_VENDOR_ID_AMCC in <linux/pci_ids.h>. The vender ID is actually
assigned to Applied Micro Circuits Corporation. The 8250_pci driver
uses PCI_VENDOR_ID_ADDIDATA_OLD in the lists of quirks and PCI IDs for
the ADDI-DATA APCI-7800 card. Change it to use the more accurate
PCI_VENDOR_ID_AMCC.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds support to ASC (asynchronous serial controller)
driver, which is basically a standard serial driver. This IP is common
across all the ST parts for settop box platforms.
ASC is embedded in ST COMMS IP block. It supports Rx & Tx functionality.
It support all industry standard baud rates.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
CC: Stephen Gallimore <stephen.gallimore@st.com>
CC: Stuart Menefy <stuart.menefy@st.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The driver fails to build on x86 because writel_relaxed isn't available
there. That function exists on arm, arm64, avr32, hexagon, mips and sh,
but adding all these is overkill so stick to arm only.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add the missing iounmap() before return from msm_request_port()
in the error handling case.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
No idea why we have redundant testing for ifdef CONFIG_SERIAL_BFIN_MODULE,
check it once is enough.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Sonic Zhang <sonic.zhang@analog.com>
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>
Some serial ports will not use the standard base baud rate. Report
this after initialization so it might be discovered and used for early
console configuration.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If earlyprintk is enabled and current UART is console port the platform
code can mark it as RPM_ACTIVE to sync real IP state with PM Runtime and
avoid resuming of already active device, but now, driver initialization
will be performed in the wrong way:
pm_runtime_enable(&pdev->dev);
<-- PM runtime alowed (device state RPM_ACTIVE)
if (omap_up_info->autosuspend_timeout == 0)
omap_up_info->autosuspend_timeout = -1;
device_init_wakeup(up->dev, true);
pm_runtime_use_autosuspend(&pdev->dev);
<-- update_autosuspend() will be called and it will disable device
(device state RPM_SUSPENDED)
pm_runtime_set_autosuspend_delay(&pdev->dev,
omap_up_info->autosuspend_timeout);
<-- update_autosuspend() will be called which will re-enable device
(device state RPM_ACTIVE), because autosuspend_timeout < 0
pm_runtime_irq_safe(&pdev->dev);
pm_runtime_get_sync(&pdev->dev);
<-- will do nothing
Such behavior isn't expected by OMAP serial drivers and causes
unpredictable calls of serial_omap_runtime_suspend() and
serial_omap_runtime_resume().
Hence, fix it by allowing PM runtime only after all its parameters are
configured.
CC: Tony Lindgren <tony@atomide.com>
CC: Rajendra Nayak <rnayak@ti.com>
CC: Felipe Balbi <balbi@ti.com>
CC: Kevin Hilman <khilman@linaro.org>
Tested-by: Mark Jackson <mpfj-list@newflow.co.uk>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Function lpuart_setup_watermark() clears some bits in register UARTCR2
before writing FIFO configuration registers as required by hardware.
But it should restore UARTCR2 after that. Otherwise, we end up changing
UARTCR2 register when setting up watermark, and that is not really
desirable. At least, when low-level debug and earlyprint is enabled,
serial console is broken due to it.
Fix the problem by restoring UARTCR2 register at the end of function
lpuart_setup_watermark().
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Otherwise serial driver would crash accessing platform_data that was
not initialized in functions like:
serial_omap_pm(...)
...
if (!state && pdata->enable_wakeup)
^^^^^^^
...
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The revision register is a 32 bit register. The serial_in() function reads
only the lower 16 bits of the register. This leads to an incorrect computation
of the Module revision.
Signed-off-by: Ruchika Kharwar <ruchika@ti.com>
[oleksandr.savchenko@ti.com: add some whitespaces]
Signed-off-by: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Current logic results in interrupt storm since the fifo
is constantly below the threshold level. Change the logic
to fill all the available spaces in the fifo as long as
we have data to minimize the possibilty of underflow and
elimiate excessive interrupts.
Signed-off-by: Dmitry Fink <finik@ti.com>
Signed-off-by: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
wer has TX wakeup bit available enable the same
by populating the necessary tx wakeup flag for the
applicable module ip blocks and use the same
while configuaring wer reg.
Also wer is not context restored, restore wer when
context is lost.
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Kevin Hilman <kevin.hilman@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(for drivers/tty changes)
Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The recent regression about NetMos 9835 Multi-I/O boards indicates
that comment pointing to the parport_serial driver could be helpful.
Signed-off-by: Stefan Seyfried <seife+kernel@b1-systems.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds support for MAX14830 (advanced quad universal asynchronous
receiver-transmitter) into max310x driver.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds support for MAX3109 (advanced dual universal asynchronous
receiver-transmitter) into max310x driver.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch rework max310x driver.
Major changes have been made:
- Prepare driver to support ICs with more than one UART.
- Prepare driver to support work with I2C-bus.
The patch changes almost every function and can not be divided into parts.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We only enable the DMA support when the following are meet:
[1] The uart port supports the hardware flow control(CTS/RTS).
(Some uart port does not support the CTS/RTS.)
[2] The application enables the CTS/RTS.
[3] The Soc is imx6q.
For the sdma's firmware limit, we do not support the DMA except
the imx6q platform.
[4] The uart is not used as a console.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It was not possible to set custom-baudrates like 62500.
Signed-off-by: Hubert Feurstein <h.feurstein@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We will add the DMA support for the imx uart. For the firmware's limit,
only the imx6 serial chips (including the imx6q, imx6dl, imx6sl) can
support the DMA.
This patch adds the necessary macro and helper to distinguish the
imx6q uart from the other imx uart. Other chips can use the "fsl,imx6q-uart"
to enable the DMA support.
This patch also replaces the check "is_imx21_uart()" with "!is_imx1_uart()".
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The uart_console() check makes the clocks(clk_per and clk_ipg) opened
even when we close the console uart.
This patch enable/disable the clocks in imx_console_write(),
so we can keep the clocks closed when the console uart is closed.
Also remove the clock enable/disable oprations in the probe, we do not
need them any more.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d06310
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Barry Song <baohua.song@csr.com>
Acked-by: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ttyTHS is consistent with the name used in driver.
Signed-off-by: Richard Zhao <rizhao@nvidia.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The earlier change to use strlcpy uncovered a bug in the options
argument length calculation causing last character to be truncated.
This makes the actual console to be configured with incorrect
baudrate when specifying the console using console=uart,... syntax.
Bug symptom seen in kernel log output:
Kernel command line: console=uart,mmio,0x90000000,115200
Early serial console at MMIO 0x90000000 (options '11520')
which then results in a invalid baud rate 11520 instead of the
expected 115200 when the console is switched to ttyS0 later
in the boot process.
Signed-off-by: Henrik Nordstrom <henrik@henriknordstrom.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a static checker fix and I don't have a way to test it. But
from the context it looks like this is a typo where SCABUFSIZE was
intended instead of sizeof(SCABUFSIZE). SCABUFSIZE is 1024 and
sizeof(int) is 4. I would suspect this is a bad bug.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Implement the dtr_rts() hvc console callback to improve control when to
disconnect the IUCV connection. Previously, the IUCV connection was
disconnected during the notifier_del() callback, i.e., when the last file
descriptor to the hvc terminal device was closed.
Recent changes in login programs caused undesired disconnects during the
login phase. To prevent these kind of disconnects, implement the dtr_rts
callback to implicitly handle the HUPCL termios control via the hvc_console
driver.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce a new callback to explicitly handle the HUPCL termios control flag.
This prepares for a follow-up commit for the hvc_iucv device driver to
improve handling when to drop an established network connection.
The callback naming is based on the recently added tty_port interface to
facilitate a potential refactoring of the hvc_console to use tty_port
functions.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since commit ab78029 (drivers/pinctrl: grab default handles from device core),
we can rely on device core for setting the default pins. Compile tested only.
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Specifically:
n_gsm.c:810: ERROR: space required before the open parenthesis '('
n_gsm.c:830: WARNING: line over 80 characters
n_gsm.c:971: ERROR: trailing whitespace
n_gsm.c:984: ERROR: code indent should use tabs where possible
n_gsm.c:984: WARNING: please, no space before tabs
n_gsm.c:984: WARNING: please, no spaces at the start of a line
n_gsm.c:1141: WARNING: space prohibited before semicolon
n_gsm.c:1743: ERROR: space required before the open brace '{'
n_gsm.c:1744: WARNING: line over 80 characters
n_gsm.c:1745: ERROR: code indent should use tabs where possible
n_gsm.c:1746: ERROR: code indent should use tabs where possible
n_gsm.c:2908: WARNING: line over 80 characters
n_gsm.c:2912: ERROR: trailing whitespace
Signed-off-by: Aldo Iljazi <neonsync1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acquiring the write_wait queue spin lock now accounts for the largest
slice of cpu time on the tty write path. Two factors contribute to
this situation; a overly-pessimistic line discipline write loop which
_always_ sets up a wait loop even if i/o will immediately succeed, and
on ptys, a wakeup storm from reads and writes.
Writer wakeup does not need to be performed by the pty driver.
Firstly, since the actual i/o is performed within the write, the
line discipline write loop will continue while space remains in
the flip buffers. Secondly, when space becomes avail in the
line discipline receive buffer (and thus also in the flip buffers),
the pty unthrottle re-wakes the writer (non-flow-controlled line
disciplines unconditionally unthrottle the driver when data is
received). Thus, existing in-kernel i/o is guaranteed to advance.
Finally, writer wakeup occurs at the conclusion of the line discipline
write (in tty_write_unlock()). This guarantees that any user-space write
waiters are woken to continue additional i/o.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LNEXT processing accounts for ~15% of total cpu time in end-to-end
tty i/o; factor the lnext test/clear from the per-char i/o path.
Instead, attempt to immediately handle the literal next char if not
at the end of this received buffer; otherwise, handle the first char
of the next received buffer as the literal next char, then continue
with normal i/o.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Always pre-figure the space available in the read_buf and limit
the inbound receive request to that amount.
For compatibility reasons with the non-flow-controlled interface,
n_tty_receive_buf() will continue filling read_buf until all data
has been received or receive_room() returns 0.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert to modal receive_buf processing; factor char receive
processing for unusual termios settings out of normal per-char
i/o path.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Factor 'special' per-char processing into standalone fn,
n_tty_receive_char_special(), which handles processing for chars
marked in the char_map.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Relocate the IXANY restart tty test to code paths where the
the received char is not START_CHAR, STOP_CHAR, INTR_CHAR,
QUIT_CHAR or SUSP_CHAR.
Fixes the condition when ISIG if off and one of INTR_CHAR,
QUIT_CHAR or SUSP_CHAR does not restart i/o.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Simplify __receive_buf() into a dispatch function; perform per-char
processing for all other modes not already handled.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 20bafb3d23
'n_tty: Move buffers into n_tty_data'
broke the ppc64 build.
Include vmalloc.h for the required function declarations.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert to modal receive_buf() processing; factor receive char
processing when tty->closing into n_tty_receive_buf_closing().
Note that EXTPROC when ISTRIP or IUCLC is set continues to be
handled by n_tty_receive_char().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When EXTPROC is set without ISTRIP or IUCLC, processing is
identical to raw mode; handle this receiving mode as a special-case
of raw mode.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert to modal receive_buf() processing; factor raw mode
per-char i/o into n_tty_receive_buf_raw().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prepare for modal receive_buf() handling; factor handling for
TTY_BREAK, TTY_PARITY, TTY_FRAME and TTY_OVERRUN into
n_tty_receive_char_flagged().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reduce the monolithic n_tty_receive_char() complexity; factor the
handling of INTR_CHAR, QUIT_CHAR and SUSP_CHAR into
n_tty_receive_signal_char().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The char and flag buffer local alias pointers, p and f, are
unnecessary; remove them.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In canonical mode, an EOF which is not the first character of the line
causes read() to complete and return the number of characters read so
far (commonly referred to as EOF push). However, if the previous read()
returned because the user buffer was full _and_ the next character
is an EOF not at the beginning of the line, read() must not return 0,
thus mistakenly indicating the end-of-file condition.
The TTY_PUSH flag is used to indicate an EOF was received which is not
at the beginning of the line. Because the EOF push condition is
evaluated by a thread other than the read(), multiple EOF pushes can
cause a premature end-of-file to be indicated.
Instead, discover the 'EOF push as first read character' condition
from the read() thread itself, and restart the i/o loop if detected.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Separate the head & commit indices from the tail index to avoid
cache-line contention (so called 'false-sharing') between concurrent
threads.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since neither echo_commit nor echo_tail can change for the duration
of __process_echoes loop, substitute index comparison for the
snapshot counter.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Don't have the driver flush received echoes if no echoes were
actually output.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Byte-by-byte echo output is painfully slow, requiring a lock/unlock
cycle for every input byte.
Instead, perform the echo output in blocks of 256 characters, and
at least once per flip buffer receive. Enough space is reserved in
the echo buffer to guarantee a full block can be saved without
overrunning the echo output. Overrun is prevented by discarding
the oldest echoes until enough space exists in the echo buffer
to receive at least a full block of new echoes.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use output_lock mutex as a memory barrier when storing echo_commit.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adding data to echo_buf (via add_echo_byte()) is guaranteed to be
single-threaded, since all callers are from the n_tty_receive_buf()
path. Processing the echo_buf can be called from either the
n_tty_receive_buf() path or the n_tty_write() path; however, these
callers are already serialized by output_lock.
Publish cumulative echo_head changes to echo_commit; process echo_buf
from echo_tail to echo_commit; remove echo_lock.
On echo_buf overrun, claim output_lock to serialize changes to
echo_tail.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prepare for lockless echo_buf handling; compute current byte count
of echo_buf from head and tail indices.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instead of using a single index to track the current echo_buf position,
use a head index when adding to the buffer and a tail index when
consuming from the buffer. Allow these head and tail indices to wrap
at max representable value; perform modulo reduction via helper
functions when accessing the buffer.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The echo_overrun field is only assigned and never tested; remove it.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
TTY_BUFFER_PAGE is only used within drivers/tty/tty_buffer.c;
relocate to that file scope.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert the tty_buffer_flush() exclusion mechanism to a
public interface - tty_buffer_lock/unlock_exclusive() - and use
the interface to safely write the paste selection to the line
discipline.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
__tty_flush_buffer() is now only called by tty_flush_buffer();
merge functions.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Atomic bit ops are no longer required to indicate a flip buffer
flush is pending, as the flush_mutex is sufficient barrier.
Remove the unnecessary port .iflags field and localize flip buffer
state to struct tty_bufhead.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that dropping the buffer lock is not necessary (as result of
converting the spin lock to a mutex), the flip buffer flush no
longer needs to be handled by the buffer work.
Simply signal a flush is required; the buffer work will exit the
i/o loop, which allows tty_buffer_flush() to proceed.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The buffer work may race with parallel tty_buffer_flush. Use a
mutex to guarantee exclusive modify access to the head flip
buffer.
Remove the unneeded spin lock.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Driver-side flip buffer input is already single-threaded; 'publish'
the .next link as the last operation on the tail buffer so the
'consumer' sees the already-completed flip buffer.
The commit buffer index is already 'published' by driver-side functions.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Lockless flip buffers require atomically updating the bytes-in-use
watermark.
The pty driver also peeks at the watermark value to limit
memory consumption to a much lower value than the default; query
the watermark with new fn, tty_buffer_space_avail().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use a 0-sized sentinel to avoid assigning the head ptr from
the driver side thread. This also eliminates testing head/tail
for NULL.
When the sentinel is first 'consumed' by the buffer work
(or by tty_buffer_flush()), it is detached from the list but not
freed nor added to the free list. Both buffer work and
tty_buffer_flush() continue to preserve at least 1 flip buffer
to which head & tail is pointed.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In preparation for lockless flip buffers, make the flip buffer
free list lockless.
NB: using llist is not the optimal solution, as the driver and
buffer work may contend over the llist head unnecessarily. However,
test measurements indicate this contention is low.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_buffer_find() implements a simple free list lookaside cache.
Merge this functionality into tty_buffer_alloc() to reflect the
more traditional alloc/free symmetry.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since flip buffers are size-aligned to 256 bytes and all flip
buffers 512-bytes or larger are not added to the free list, the
free list only contains 256-byte flip buffers.
Remove the list search when allocating a new flip buffer.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The char_buf_ptr and flag_buf_ptr values are trivially derived from
the .data field offset; compute values as needed.
Fixes a long-standing type-mismatch with the char and flag ptrs.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Scheduling buffer work on the same cpu as the read() thread
limits the parallelism now possible between the receive_buf path
and the n_tty_read() path.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The pty driver forces ldisc flow control on, regardless of available
receive buffer space, so the writer can be woken whenever unthrottle
is called. However, this 'forced throttle' has performance
consequences, as multiple atomic operations are necessary to
unthrottle and perform the write wakeup for every input line (in
canonical mode).
Instead, short-circuit the unthrottle if the tty is a pty and perform
the write wakeup directly.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prepare to special case pty flow control; avoid forward declaration.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prepare for special handling of pty throttle/unthrottle; factor
flow control into helper functions.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prepare to factor throttle and unthrottle into helper functions;
relocate chars_in_buffer() to avoid forward declaration.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
No tty driver modifies termios during throttle() or unthrottle().
Therefore, only read safety is required.
However, tty_throttle_safe and tty_unthrottle_safe must still be
mutually exclusive; introduce throttle_mutex for that purpose.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the read buffer indices are in the same cache-line, cpus will
contended over the cache-line (so called 'false sharing').
Separate the producer-published fields from the consumer-published
fields; document the locks relevant to each field.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
User-space read() can run concurrently with receiving from device;
waiting for receive_buf() to complete is not required.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
lnext escapes the next input character as a literal, and must
be reset when canonical mode changes (to avoid misinterpreting
a special character as a literal if canonical mode is changed
back again).
lnext is specifically not reset on a buffer flush so as to avoid
misinterpreting the next input character as a special character.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
n_tty has a single-producer/single-consumer input model;
use lockless publish instead.
Use termios_rwsem to exclude both consumer and producer while
changing or resetting buffer indices, eg., when flushing. Also,
claim exclusive termios_rwsem to safely retrieve the buffer
indices from a thread other than consumer or producer
(eg., TIOCINQ ioctl).
Note the read_tail is published _after_ clearing the newline
indicator in read_flags to avoid racing the producer.
Drop read_lock spinlock.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
canon_data represented the # of lines which had been copied
to the receive buffer but not yet copied to the user buffer.
The value was tested to determine if input was available in
canonical mode (and also to force input overrun if the
receive buffer was full but a newline had not been received).
However, the actual count was irrelevent; only whether it was
non-zero (meaning 'is there any input to transfer?'). This
shared count is unnecessary and unsafe with a lockless algorithm.
The same check is made by comparing canon_head with read_tail instead.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use termios_rwsem to guarantee safe access to the termios values.
This is particularly important for N_TTY as changing certain termios
settings alters the mode of operation.
termios_rwsem must be dropped across throttle/unthrottle since
those functions claim the termios_rwsem exclusively (to guarantee
safe access to the termios and for mutual exclusion).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Storing the read_cnt creates an unnecessary shared variable
between the single-producer (n_tty_receive_buf()) and the
single-consumer (n_tty_read()).
Compute read_cnt from head & tail instead of storing.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Wrap read_buf indices (read_head, read_tail, canon_head) at
max representable value, instead of at the N_TTY_BUF_SIZE. This step
is necessary to allow lockless reads of these shared variables
(by updating the variables atomically).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prepare for replacing read_cnt field with computed value.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
N_TTY .chars_in_buffer() method requires serialized access if
the current thread is not the single-consumer, n_tty_read().
Separate the internal interface; prepare for lockless read-side.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instead of pushing one char per loop, pre-compute the data length
to copy and copy all at once.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Although line discipline receiving is single-producer/single-consumer,
using tty->receive_room to manage flow control creates unnecessary
critical regions requiring additional lock use.
Instead, introduce the optional .receive_buf2() ldisc method which
returns the # of bytes actually received. Serialization is guaranteed
by the caller.
In turn, the line discipline should schedule the buffer work item
whenever space becomes available; ie., when there is room to receive
data and receive_room() previously returned 0 (the buffer work
item stops processing if receive_buf2() returns 0). Note the
'no room' state need not be atomic despite concurrent use by two
threads because only the buffer work thread can set the state and
only the read() thread can clear the state.
Add n_tty_receive_buf2() as the receive_buf2() method for N_TTY.
Provide a public helper function, tty_ldisc_receive_buf(), to use
when directly accessing the receive_buf() methods.
Line disciplines not using input flow control can continue to set
tty->receive_room to a fixed value and only provide the receive_buf()
method.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ldisc interface functions must be called with interrupts enabled.
Separating the ldisc calls into a helper function simplies the
eventual removal of the spinlock.
Note that access to the buf->head ptr outside the spinlock is
safe here because;
* __tty_buffer_flush() is prevented from running while buffer work
performs i/o,
* tty_buffer_find() only assigns buf->head if the flip buffer list
is empty (which is never the case in flush_to_ldisc() since at
least one buffer is always left in the list after use)
Access to the read index outside the spinlock is safe here for the
same reasons.
Update the buffer's read index _after_ the data has been received
by the ldisc.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_set_ldisc() is guaranteed exclusive use of the line discipline
by tty_ldisc_lock_pair_timeout(); shutting off input by resetting
receive_room is unnecessary.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The hangup may already have happened; check for that state also.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rename o_ldisc to avoid confusion with the ldisc of the
'other' tty.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Line discipline locking was performed with a combination of
a mutex, a status bit, a count, and a waitqueue -- basically,
a rw semaphore.
Replace the existing combination with an ld_semaphore.
Fixes:
1) the 'reference acquire after ldisc locked' bug
2) the over-complicated halt mechanism
3) lock order wrt. tty_lock()
4) dropping locks while changing ldisc
5) previously unidentified deadlock while locking ldisc from
both linked ttys concurrently
6) previously unidentified recursive deadlocks
Adds much-needed lockdep diagnostics.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Just as the tty pair must be locked in a stable sequence
(ie, independent of which is consider the 'other' tty), so must
the ldisc pair be locked in a stable sequence as well.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The file scope spinlock identifier, tty_ldisc_lock, will collide
with the file scope lock function tty_ldisc_lock() so rename it.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull MIPS updates from Ralf Baechle:
"MIPS updates:
- All the things that didn't make 3.10.
- Removes the Windriver PPMC platform. Nobody will miss it.
- Remove a workaround from kernel/irq/irqdomain.c which was there
exclusivly for MIPS. Patch by Grant Likely.
- More small improvments for the SEAD 3 platform
- Improvments on the BMIPS / SMP support for the BCM63xx series.
- Various cleanups of dead leftovers.
- Platform support for the Cavium Octeon-based EdgeRouter Lite.
Two large KVM patchsets didn't make it for this pull request because
their respective authors are vacationing"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (124 commits)
MIPS: Kconfig: Add missing MODULES dependency to VPE_LOADER
MIPS: BCM63xx: CLK: Add dummy clk_{set,round}_rate() functions
MIPS: SEAD3: Disable L2 cache on SEAD-3.
MIPS: BCM63xx: Enable second core SMP on BCM6328 if available
MIPS: BCM63xx: Add SMP support to prom.c
MIPS: define write{b,w,l,q}_relaxed
MIPS: Expose missing pci_io{map,unmap} declarations
MIPS: Malta: Update GCMP detection.
Revert "MIPS: make CAC_ADDR and UNCAC_ADDR account for PHYS_OFFSET"
MIPS: APSP: Remove <asm/kspd.h>
SSB: Kconfig: Amend SSB_EMBEDDED dependencies
MIPS: microMIPS: Fix improper definition of ISA exception bit.
MIPS: Don't try to decode microMIPS branch instructions where they cannot exist.
MIPS: Declare emulate_load_store_microMIPS as a static function.
MIPS: Fix typos and cleanup comment
MIPS: Cleanup indentation and whitespace
MIPS: BMIPS: support booting from physical CPU other than 0
MIPS: Only set cpu_has_mmips if SYS_SUPPORTS_MICROMIPS
MIPS: GIC: Fix gic_set_affinity infinite loop
MIPS: Don't save/restore OCTEON wide multiplier state on syscalls.
...
