On many new Intel SoCs the UART has an integrated DMA engine
(iDMA). In order to use it a special filter function is needed.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function clk_prepare_enable() may fail, and in that case it
does not make sense to proceed. Let's check its return code and
error out if it is a negative value.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The probe method of this driver calls clk_get(), but clk_put() is
missing from the remove callback.
Using the managed clk function is easier than fixing other parts.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Support command line parameters of the form:
earlycon=<name>,io|mmio|mmio32|mmio32be,<addr>,<options>
This commit seem to be needed even after commit:
serial: 8250: Add support for big-endian MMIO accesses
c627f2ceb6
Signed-off-by: Noam Camus <noamc@ezchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
when the serial works as a bluetooth sink, due to audio realtime
requirement, the driver should have something similar with ALSA:
1. one big DMA buffer to easy the schedule jitter
2. split this big DMA buffer to multiple small periods, for each
period, we get a DMA interrupt, then push the data to userspace.
the small periods will easy the audio latency.
so ALSA generally uses a cyclic chained DMA.
but for sirfsoc, the dma hardware has the limitation: we have
only two loops in the cyclic mode, so we can only support two
small periods to switch. if we make the DMA buffer too big, we
get long latency, if we make the DMA buffer too little, we get
miss in scheduling for audio realtime.
so this patch moves to use a hrtimer to simulate the cyclic
DMA, then we can have a big buffer, and also have a timely
data push to users as the hrtimer can generate in small period
then actual HW interrupts.
with this patch, we also delete a lot of complex codes to handle
loop buffers, and RX timeout interrupt since the RX work can be
completely handled from hrtimer interrupt.
tests show using this way will make our bad audio streaming be-
come smooth.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A corner case exists in the current driver. if an app opens the console
device, and before writing to console device, and there are huge kernel
ogs to print out, system will hang on
sirfsoc_uart_console_putchar:
while (rd_regl(port, ureg->sirfsoc_tx_fifo_status) &
ufifo_st->ff_full(port->line))
cpu_relax();
as in sirfsoc_uart_startup(), the driver assigns tx_fifo_op to 0 will stop
TX FIFO, this loop will be endless.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial8250_set_mctrl() is a void type function. Returning something
does not look nice.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
RS-485 configuration is also done under the spinlock
so no blocking I/O allowed.
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
.stop_rx/tx() are called in atomic context, we cannot use
blocking I/O. While at it correct the name of RX bit and
'*' placement in pointer declarations.
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert md_proc into general async reconfiguration procedure.
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instead of spinning under port->lock let's just sleep
inside the kthread. It should be equivalent as TX cannot
proceed when thread is blocked.
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert workqueue usage to a real-time kworker. The problem
with workqueues is that we cannot set real-time priorities on
our work and asynchronous reconfiguration can be blocked by
less important tasks.
We need kthread for the interrupt anyway and because we will
now be using single kthread for all TX-related operations we
can get rid of the port mutex.
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LSR_TEMT_BIT (LSR bit 6) provides us exactly the information
we need to determine if transmission is finished - FIFO level
and shift register empty. We can save ourselves reading FIFO
level explicitly if we use this bit.
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Without matching bus-specific strings driver will not be loaded
automatically.
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Users of RS-485 can request via ioctl that RTS signals should
be activated selected number of milliseconds before the actual
data transmission or delay reception certain number of milli-
seconds after the transmission is finished. In sc16is7xx,
however, RTS signalling is handled by the hardware and driver
has no way of providing this feature.
We still try to provide .delay_rts_before_send by delaying
transmission but without actual effect on the RTS line.
Note: this change will make the driver return -EINVAL when the
feature is requested (.delay_rts_after_send is set).
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
spi interface for sc16is7xx is added along with Kconfig flag
to enable spi or i2c, thus in a instance we can have either
spi or i2c or both, in sync to the hw.
Signed-off-by: Rama Kiran Kumar Indrakanti <indrakanti_ram@hotmail.com>
Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add the necessary driver boilerplate to let the driver be used when
the respective ACPI table is discovered by the ACPI subsystem.
[Andre: change table name, add MODULE_DEVICE_TABLE entry and improve
commit message]
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The ARM Server Base System Architecture[1] document describes a
generic UART which is a subset of the PL011 UART.
It lacks DMA support, baud rate control and modem status line
control, among other things.
The idea is to move the UART initialization and setup into the
firmware (which does this job today already) and let the kernel just
use the UART for sending and receiving characters.
We use the recent refactoring to build a new struct uart_ops
variable which points to some new functions avoiding access to the
missing registers. We reuse as much existing PL011 code as possible.
In contrast to the PL011 the SBSA UART does not define any AMBA or
PrimeCell relations, so we go with a pretty generic probe function
which only uses platform device functions.
A DT binding is provided with this patch, ACPI support is added in a
separate one.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The SBSA UART has a fixed baud rate and flow control setting, which
cannot be changed or queried by software.
Add a vendor specific property to always return fixed values when
trying to read the console options.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The SBSA UART should not be enabled or disabled (it is always on),
and consequently the spec lacks the UART_CR register.
Add a vendor specific property to skip disabling or enabling of the
UART. This will be used later by the SBSA UART support.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To avoid lines with more than 80 characters and to make the
pl011_int() function more readable, move the workaround out into a
separate function.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The PL011 register UART_MIS is actually a bitwise AND of the
UART_RIS and the UART_MISC register.
Since the SBSA UART does not include the _MIS register, use the
two separate registers to get the same behaviour. Since we are
inside the spinlock and we read the _IMSC register only once, there
should be no race issue.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently the pl011_probe() function is relying on some AMBA IDs
and a device tree node to initialize the driver and a port.
Both features are not necessarily required for the driver:
- we lack AMBA IDs in the ARM SBSA generic UART and
- we lack a DT node in ACPI systems.
So lets refactor the function to ease later reuse.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Split the pl011_set_termios() function into smaller chunks to allow
easier reuse later when adding SBSA support.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Split the pl011_shutdown() function into smaller chunks to allow
easier reuse later when adding SBSA support.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Split the pl011_startup() function into smaller chunks to allow
easier reuse later when adding SBSA support.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Although we care about not unregistering the driver if there are
still ports connected during the .remove callback, we do miss this
check in the pl011_probe function. So if the current port allocation
fails, but there are other ports already registered, we will kill
those.
So factor out the port removal into a separate function and use that
in the probe function, too.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Naresh Bhat <nbhat@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the mediatek serial port driver is built-in, but serial
console is disabled in Kconfig (e.g. when the serial driver
itself is a loadable module), we get this build error:
drivers/built-in.o: In function `early_mtk8250_setup':
undefined reference to `early_serial8250_setup'
To avoid that problem, this patch encloses the early_mtk8250_setup
function in #ifdef CONFIG_SERIAL_8250_CONSOLE, the same symbol
that guards the early_serial8250_setup function.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Eddie Huang <eddie.huang@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A configuration that enables earlycon but not the core console
code causes a link error:
drivers/built-in.o: In function `setup_earlycon':
drivers/tty/serial/earlycon.c:70: undefined reference to `uart_parse_earlycon'
That error can be triggered by the newly added samsung earlycon support,
which is missing a 'select' statement.
As suggested by Peter Hurley, solves the problem by moving the
'select SERIAL_EARLYCON' statement to the samsung console driver
option, as it is done by all other console drivers.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: b94ba0328d ("serial: samsung: Add support for early console")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function mctrl_gpio_init returns failure if the assignment to any
member of the gpio array results in an error pointer. So there is no
need to check for such error values in the other functions.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The currently in-use port->startup and port->shutdown are "okay". The
startup part for instance does the tiny omap extra part and invokes
serial8250_do_startup() for the remaining pieces. The workflow in
serial8250_do_startup() is okay except for the part where UART_RX is
read without a check if there is something to read. I tried to
workaround it in commit 0aa525d118 ("tty: serial: 8250_core: read only
RX if there is something in the FIFO") but then reverted it later in
commit ca8bb4aefb ("serial: 8250: Revert "tty: serial: 8250_core: read
only RX if there is something in the FIFO"").
This is the second attempt to get it to work on older OMAPs without
breaking other chips this time
Peter Hurley suggested to pull in the few needed lines from
serial8250_do_startup() and drop everything else that is not required
including making it simpler like using just request_irq() instead the
chain handler like it is doing now.
So lets try that.
Fixes: ca8bb4aefb ("serial: 8250: Revert "tty: serial: 8250_core:
read only RX if there is something in the FIFO"")
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the call to dmaengine_slave_config() fails, then the DMA buffer will
not be freed/unmapped. Fix this by moving the code that stores the
address of the buffer in the tegra_uart_port structure to before the
call to dmaengine_slave_config().
Reported-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
it seems this is a more typical behaviour from reviewing other console
drivers.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
add overrun error's flag mark and parity's counter, we can show the
statistic from procfs node.
BTW, let the indentation of stick bits configuration look better.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In special condition, when cpu schedule into rx_tmo_process_tl or
rx_dma_complete_tl and all the receive dma tasks have done, it will
go into endless loop because no dma task cookie status be changed.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>From HW spec, when rxfifo's data is less than AFC_RX_THD(RX threshhold), RTS
signal is active. otherwise, RTS signal is inactive.
Crrently the RX threshhold is set as zero, so RTS has no chance to be
active. This patch replaces the default 0 by a positive number.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
differentiate difference port types by re-defining the status MARCO
or putting HW differences into private data of the related ports.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In RS485 mode, we may want to set the delay_rts_after_send value to 0.
In the datasheet, the 0 value is said to "disable" the Transmitter Timeguard but
this is exactly the expected behavior if we want no delay...
Moreover, if the value was set to non-zero value by device-tree or earlier
ioctl command, it was impossible to change it back to zero.
Reported-by: Sami Pietikäinen <Sami.Pietikainen@wapice.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: stable@vger.kernel.org # 3.2+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In commit 02730d3c05
(Merge 4.1-rc4 into tty-next), git mismerged some lines,
reintroducing a reference to the removed field
uart_amba_port.tx_irq_seen. This causes a build failure.
This patch removes the mismerged lines, restoring the code to what
was in tty-next (which was the intention).
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This code is no longer used now that mach-msm has been removed.
Delete it.
Cc: David Brown <davidb@codeaurora.org>
Cc: Bryan Huntsman <bryanh@codeaurora.org>
Cc: Daniel Walker <dwalker@fifo99.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Function tegra_uart_dma_channel_allocate() does not check that
dma_map_single() mapped the DMA buffer correctly. Add a check for this
and appropriate error handling.
Furthermore, if dmaengine_slave_config() (called by
tegra_uart_dma_channel_allocate()) fails, then memory allocated/mapped
is not freed/unmapped. Therefore, call tegra_uart_dma_channel_free()
instead of just dma_release_channel() if dmaengine_slave_config() fails.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are two issues in the shutdown path of the UARTs which are:
1. The function tegra_uart_shutdown() calls tegra_uart_flush_buffer()
to stop DMA TX transfers. However, tegra_uart_flush_buffer() is
called after the DMA channels have already been freed and so actually
does nothing.
2. The function that frees the DMA channels
(tegra_uart_dma_channel_free()), unmaps the dma buffer before
freeing the DMA channel and does not ensure the DMA has been
stopped.
Resolve this by fixing the code in tegra_uart_dma_channel_free() to
ensure the DMA is stopped, free the DMA channel and then unmap the DMA
buffer. Finally, remove the unnecessary call to tegra_uart_flush_buffer().
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The DMA cookie for the RX channel is being used by the TX channel.
Therefore, fix driver to use the correct DMA cookie for the TX channel.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function tty_insert_flip_string() takes an argument "size" which is
of type size_t. This is an unsigned type. Update the count,
rx_bytes_requested and tx_bytes_requested in the tegra serial driver to
be unsigned integers so that an unsigned type is passed to
tty_insert_flip_string().
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The tegra serial driver has two paths through which receive data is
copied up to the tty layer. These are:
1. DMA completion callback
2. UART RX interrupt
A UART RX interrupt occurs for either RX_TIMEOUT (data has been sitting
in the Rx FIFO for more than 4 character times without being read
because there is not enough data to reach the trigger level), End of
Receive Data event (receiver detects that data stops coming in for more
than 4 character times) or a receive error.
In the RX interrupt path, the following happens ...
- All RX DMA transfers are stopped
- Any data in the DMA buffer and RX FIFO are copied up to the tty layer.
- DMA is restarted/primed for the RX path
In the DMA completion callback, the DMA buffer is copied up to the tty
layer but there is no check to see if the RX interrupt could have
occurred between the DMA interrupt firing the the DMA callback running.
Hence, if a RX interrupt was to occur shortly after the DMA completion
interrupt, it is possible that the RX interrupt path has already copied
the DMA buffer before the DMA callback has been called. Therefore, when
the DMA callback is called, if the DMA is already in-progress, then this
indicates that the UART RX interrupt has already occurred and there is
nothing to do in the DMA callback. This race condition can cause
duplicated data to be received.
Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
[jonathanh@nvidia.com: Moved async_tx_ack() call to after check to see
if DMA has completed because if the DMA is in progress we do not need
to ACK yet. Changed the print from dev_info to dev_debug. Updated
changelog to add more commentary on the race condition based upon
feedback from author.]
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It is only necessary to read data from the dma buffer when the count
value is non-zero and hence, tegra_uart_copy_rx_to_tty() so only be
called when this is the case.
Although, this was being tested for in two places, there is a third
place where this was not tested. However, instead of adding another
if-statement prior to calling tegra_uart_copy_rx_to_tty(), move the test
inside the function.
Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
[jonathanh@nvidia.com: Re-worked patch to move the check for the count
value inside the function tegra_uart_copy_rx_to_tty(). Updated
changelog with more commentary.]
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For all tegra devices (up to t210), there is a hardware issue that
requires software to wait for 3 UART clock periods after enabling
the TX fifo, otherwise data could be lost.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
