Commit Graph

2549 Commits

Author SHA1 Message Date
Uwe Kleine-König
dc2454f7eb serial: mxs-auart+imx: allow compile testing on non-Freescale architectures
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:46:43 +01:00
Uwe Kleine-König
c8d1f02245 serial: atmel: allow compile testing on non-atmel architectures
This commit also fixes compiler warnings and errors seen when building
on x86_64.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:45:18 +01:00
Lucas Stach
abc7882aac serial: imx: also update RX stats in DMA path
The RX bytecount was only updated in the PIO path and thus
the device erroneously reported a value of 0 if DMA is in
use.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:44:29 +01:00
Lucas Stach
7e11577ef6 serial: imx: re-enable DMA support without hardware flow control
The commit enabling DMA support even if no flow control is present
was reverted on the grounds that it uncovered a number of bugs in
the code that lead to hanging tty devices and/or missing characters.

After tracking down the issues it is clear that those were generic
bugs and had nothing to do with flow control being present or not,
only that allowing DMA without hardware flow control increased
the exposure of that code a lot.

Now that those bugs are fixed, it should be safe to re-enable DMA
support.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:43:30 +01:00
Lucas Stach
905c0decad serial: imx: don't use idle condition detect for DMA transfers
The reference manual states that idle condition detect should not be used
with DMA transfers, as the ROM SDMA scripts don't check those conditions.

The RAM SDMA scripts worked around this, but the change broke compatibility
with the ROM scripts.

The previous commits fixed the DMA burst sizes, so that the aging timer is
now working as described in the reference manual. With this fixed we can
remove the hack of using the idle condition detect to stop the DMA transfer
if there are no new characters incoming.

This should work with both the ROM and RAM SDMA scripts.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:43:06 +01:00
Lucas Stach
184bd70bbc serial: imx: configure proper DMA burst sizes
Triggering the DMA engine for every byte is horribly inefficient.
Also it doesn't allow to use the aging timer for the RX FIFO as this
requires the DMA engine to leave one byte remaining in the FIFO when
doing a normal burst transfer.

Adjust watermark levels so that the DMA engine can do at least 8 byte
burst transfers. This is a conservative value, as the both TX and RX
FIFOs are able to contain 32 bytes.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:43:06 +01:00
Lucas Stach
976b39cd5b serial: imx: always restart DMA if more data is available
Simplify the DMA restart logic to always queue up the next transfer
immediately if there is at least one more byte available in the FIFO,
so that the transfer will finish in a limited time.

This way the driver stops to rely on zero length transfers to signal
transfers ends. Those will go away when the idle detect DMA requests
are disabled.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:42:26 +01:00
Lucas Stach
86a04ba642 serial: imx: set up aging timer interrupt as DMA trigger
The DMA transfer is only started once we are sure it will finish
in a limited time, i.e. only after we received a RRDY interrupt.

In order to allow the watermark level to be raised the aging
timer and the corresponding interrupt need to be set up as an
additional trigger, so that the transfer is also started if the
incoming amount of bytes never reach the watermark.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:41:09 +01:00
Lucas Stach
cc32382d9f serial: imx: make setup_ufcr more useful
This function currently doesn't use its parameter.

Change prototype to pass in watermark levels, so we can reuse this
function in the DMA setup paths. Also relocate to be near the calling
functions.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:41:09 +01:00
Heikki Krogerus
7693c79ce0 serial: 8250_dw: don't set UPF_BOOT_AUTOCONF flag
serial8250_register_8250_port adds it to all ports it
registers. No need to set it separately.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:38:45 +01:00
Heikki Krogerus
2338a75e0f serial: 8250_dw: cleanup dw8250_setup_port
Using the same style of declaring variables as used in the
other functions of the driver. Passing uart_port to the
function instead of uart_8250_port, as it is the one mostly
needed.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:38:45 +01:00
Heikki Krogerus
83ce95ef5e serial: 8250_dw: cleanup dw8250_idma_filter
Remove the extra return.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:38:45 +01:00
Heikki Krogerus
1edb3cf21f serial: 8250_dw: rename and comment the fallback dma filter
Adding comment where the purpose of the function is
explained.

The dma parameters are not used, so removing them, and also
moving the assignment of the function to the same place
where the other dw8250_data structures members are being set
in dw8250_probe.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:38:45 +01:00
Heikki Krogerus
c73942e22a serial: 8250_dw: proper support for UARTs without busy functionality
If the DW_apb_uart is configured with UART_16550_COMPATIBLE
configuration parameter set, then the Busy Functionality is
not available. These UARTs will never generate the Busy
detect indication interrupt, and therefore don't need
handling for it.

This creates a small optimization for the DW_apb_uarts
configured without the busy functionality, but more
importantly, it removes the small but real risk of hitting
potential issues caused by busy functionality handling when
no busy functionality exist.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:38:45 +01:00
Heikki Krogerus
9e08fa50b2 serial: 8250_dw: add dw8250_quirks function
Merging the DT and ACPI specific probe functions into
dw8250_quirks. Those functions did not have that much code
any more and some of the quirks need to be shared. This
will also allow platforms without DT or ACPI to use the
driver.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:38:45 +01:00
Heikki Krogerus
4f042054fa serial: 8250_dw: only setup the port from one place
This adds a flag "skip_autocfg" that the platforms that do
not have the ADDITIONAL_FEATURES implemented can use to skip
the port setup. It's then enough to call dw8250_setup_port
just from dw8250_probe based on that flag.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:38:45 +01:00
Heikki Krogerus
2559318caa serial: 8250_dw: hook the DMA in one place
Instead of assigning the dma member in dw8250_probe_of and
dw8250_probe_acpi separately, assigning it in dw8250_probe.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:38:45 +01:00
Heikki Krogerus
1bd8edba10 serial: 8250_dw: adapt to unified device property interface
This makes the properties available for all types of
platforms instead of just the ones using DT.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:38:45 +01:00
Heikki Krogerus
78d3da75d5 serial: 8250_dw: add separate pointer for the uart_port to dw8250_probe
For convenience, adding separate pointer for the "port"
member of struct uart_8250_port that is being filled in the
probe function.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 18:38:45 +01:00
Scott Wood
d05f15707b serial: 8250: Add OF earlycon support
This allows earlycon to be used without needing to specify the I/O
address on the kernel command line, if linux,stdout-path is specified
in the chosen node.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:49:27 +01:00
Lucas Stach
913c6c0e94 serial: imx: add earlycon support
Earlycon allows to have an early debugging console that doesn't need
to be statically configured in the kernel config, like earlyprintk,
but is set up through the stdout-path DT property.

This allows to have the early debugging always built into the
kernel and enabled on demand without clashing between different boards
or architectures.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:49:27 +01:00
Alexandre Belloni
9af92fbff3 tty/serial: at91: move ATMEL_MAX_UART
Move ATMEL_MAX_UART from platform_data/atmel.h to atmel_serial.c as this is
the only file using it and it is common practise from tty/serial drivers to
define it directly in the driver file.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:47:49 +01:00
Martin Sperl
ed4492fa91 serial: of-serial: compile correctly when 8250 driver is compiled as module
If the 8250 driver is compiled as a module then
CONFIG_SERIAL_8250_MODULE is defined and not CONFIG_SERIAL_8250.

This results in all those code sections that require CONFIG_SERIAL_8250
to be defined are not included.

This patch fixes the situation and allows 8250 and of-serial to
be compiled as a module with the same functionality as when
compiled into the kernel.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:47:49 +01:00
Tobias Klauser
d144aff136 serial: altera_uart: Use of_property_read_u32 instead of open-coding it
Use of_property_read_u32 instead of of_get_property with return value
checks and endianness conversion. Also remove the !CONFIG_OF
implementation of altera_uart_get_of_uartclk as of_property_read_u32
will return a non-zero value for !CONFIG_OF.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:47:49 +01:00
Matt Redfearn
c74997bdfe serial: 8250_ingenic: Enable FIFO for Ingenic UARTs
Enable the TX/RX FIFOs present on UARTs in Ingenic SoCs.
FIFO sizes vary per device so match these based on
the OF compatible string

Enabling the FIFOs permits much faster transfer with
lower CPU overhead.

Tested on Ingenic JZ4780 on the MIPS Ci20 Creator board

Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:47:49 +01:00
Matt Redfearn
129a45b1a9 serial: 8250_ingenic: Enable hardware flow control
The Ingenic UART is similar to a standard 16550, but hardware flow control
requires setting a couple of additional, non-standard bits in the MCR.

The non-standard "modem control enable" and "hardware flow control
mode" bits are set when writing to the MCR register, based
on whether the modem control interrupt is active.

Additionally the non-16550 compliant parts of the uart need to be
masked from higher layers.

Tested on Ingenic JZ4780 on MIPS Creator Ci20 board

Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:47:49 +01:00
Javier Martinez Canillas
20b5af9350 serial: sc16is7xx: Remove unnecessary MODULE_ALIAS()
The driver has a I2C device id table that is used to create the modaliases
and also "sc16is7xx" is not a supported I2C id, so it's never used.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:44:52 +01:00
Axel Lin
57e7e2a64a serial: mux: Convert to uart_console_device instead of open-coded
The implementation of mux_console_device() is very similar to
uart_console_device(). Setting .data field in mux_console then we can
convert to use uart_console_device().

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:44:52 +01:00
Fabio Estevam
7401349608 serial: 68328serial: Use NULL for pointers
Compare pointer-typed values to NULL rather than 0

The semantic patch that makes this change is available
in scripts/coccinelle/null/badzero.cocci.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:44:52 +01:00
Robert Baldyga
09557c0169 serial: samsung: Fix UART status handling in DMA mode
So far, when interrupt occured in DMA mode, it was handled by terminating
DMA transfer and draining data remaining in RX FIFO. It worked well
until interrupt was caused by timeout, but the same interrupt can be
alse caused by special condition (eg. 'break'), which requires special
handling. In such case handling mechanism was the same - DMA transaction
was terminated and FIFO was drained, but any special conditions were
ingnored. Because of this in DMA mode there was no ability to use,
for example, Magic SysRq.

This patch fixes this problem by using s3c24xx_serial_rx_drain_fifo()
function instead of uart_rx_drain_fifo(), which does the same thing
(drains RX FIFO) plus checks UART status to detect special conditions
(such as 'break'). Thanks to this we have exactly the same UART status
handling in both DMA and PIO mode.

This change additionally simplifies RX handling code, as we no longer
need uart_rx_drain_fifo() function, so we can remove it.

Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:44:52 +01:00
Robert Baldyga
01732dd25c serial: samsung: introduce s3c24xx_serial_rx_drain_fifo() function
This patch introduces s3c24xx_serial_rx_drain_fifo() which reads data
from RX FIFO and writes it to tty buffer. It also checks for special
conditions (such as 'break') and handles it. This function has been
separated from s3c24xx_serial_rx_chars_pio() as it contains code which
can be used also in DMA mode.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:44:52 +01:00
Robert Baldyga
620bb21448 serial: samsung: remove unneded 'ignore_char' label
This label does nothing special and we don't need to have it anymore.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:44:52 +01:00
Robert Baldyga
e4678afeff serial: samsung: remove unused 'irq' parameter
This parameter is not used anywhere, so we can get rid of it.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:44:52 +01:00
Geert Uytterhoeven
ff4411296e serial: sh-sci: Add DT support to DMA setup
Add support for obtaining DMA channel information from the device tree.

This requires switching from the legacy sh_dmae_slave structures with
hardcoded channel numbers and the corresponding filter function to:
  1. dma_request_slave_channel_compat(),
       - On legacy platforms, dma_request_slave_channel_compat() uses
	 the passed DMA channel numbers that originate from platform
	 device data,
       - On DT-based platforms, dma_request_slave_channel_compat() will
	 retrieve the information from DT.
  2. and the generic dmaengine_slave_config() configuration method,
     which requires filling in DMA register ports and slave bus widths.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:36:10 +01:00
Muhammad Hamza Farooq
e7327c09de serial: sh-sci: Pause DMA engine and get DMA status again
Occasionally, DMA transaction completes _after_ DMA engine is stopped.
Verify if the transaction has not finished before forcing the engine to
stop and push the data

Signed-off-by: Muhammad Hamza Farooq <mfarooq@visteon.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:36:10 +01:00
Muhammad Hamza Farooq
3b963042b6 serial: sh-sci: Do not terminate DMA engine when race condition occurs
When DMA packet completion and timer expiry take place at the same time,
do not terminate the DMA engine, leading by submission of new
descriptors, as the DMA communication hasn't necessarily stopped here.

Signed-off-by: Muhammad Hamza Farooq <mfarooq@visteon.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:36:10 +01:00
Muhammad Hamza Farooq
1d3db608f9 serial: sh-sci: Call dma_async_issue_pending when transaction completes
dmaengine_submit() will not start the DMA operation, it merely adds
it to the pending queue.  If the queue is no longer running, it won't be
restarted until dma_async_issue_pending() is called.

Signed-off-by: Muhammad Hamza Farooq <mfarooq@visteon.com>
[geert: Add more description]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:36:10 +01:00
Muhammad Hamza Farooq
371cfed311 serial: sh-sci: Redirect port interrupts to CPU _only_ when DMA stops
Since the DMA engine is not stopped everytime rx_timer_fn is called, the
interrupts have to be redirected back to CPU only when incomplete DMA
transaction is handled

Signed-off-by: Muhammad Hamza Farooq <mfarooq@visteon.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:36:10 +01:00
Aleksandar Mitev
9ab7655660 serial: sh-sci: Remove timer on shutdown of port
This prevents DMA timer timeout that can trigger after the port has
been closed.

Signed-off-by: Aleksandar Mitev <amitev@visteon.com>
[geert: Move del_timer_sync() outside spinlock to avoid circular locking
        dependency between rx_timer_fn() and del_timer_sync()]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:36:10 +01:00
Geert Uytterhoeven
0e5c4b4d15 serial: sh-sci: Stop calling sci_start_rx() from sci_request_dma()
There's no need to call sci_start_rx() from sci_request_dma() when DMA
setup fails, as sci_startup() will call sci_start_rx() anyway.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:36:10 +01:00
Geert Uytterhoeven
756981be74 serial: sh-sci: Submit RX DMA from RX interrupt on (H)SCIF
For DMA receive requests, the driver is only notified by DMA completion
after the whole DMA request has been transferred.  If less data is
received, it will stay stuck until more data arrives.  The driver
handles this by setting up a timer handler from the receive interrupt,
after reception of the first character.

Unlike SCIFA and SCIFB, SCIF and HSCIF don't issue receive interrupts on
reception of individual characters if a receive DMA request is in
progress, so the timer is never set up.

To fix receive DMA on SCIF and HSCIF, submit the receive DMA request
from the receive interrupt handler instead.
In some sense this is similar to the SCIFA/SCIFB behavior, where the
RDRQE (Rx Data Transfer Request Enable) bit is also set from the receive
interrupt handler.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:36:10 +01:00
Geert Uytterhoeven
67f462b069 serial: sh-sci: Get rid of the workqueue to handle receive DMA requests
The receive DMA workqueue function work_fn_rx() handles two things:
  1. Reception of a full buffer on completion of a receive DMA request,
  2. Reception of a partial buffer on receive DMA time-out.
The workqueue is kicked by both the receive DMA completion handler, and
by a timer to handle DMA time-out.

As there are always two receive DMA requests active, it's possible that
the receive DMA completion handler is called a second time before the
workqueue function runs.

As the time-out handler re-enables the receive interrupt, an interrupt
may come in before time-out has been fully handled.

Move part 1 into the receive DMA completion handler, and move part 2
into the receive DMA time-out handler, to fix these race conditions.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:36:10 +01:00
Geert Uytterhoeven
e1910fcdb5 serial: sh-sci: Shuffle functions around
This allows to:
  - Remove forward declarations of static functions,
  - Coalesce two sections protected by #ifdef CONFIG_SERIAL_SH_SCI_DMA,
  - Avoid shuffling functions around in the near future,
  - Avoid adding forward declarations in the near future.

No functional changes.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:36:10 +01:00
Geert Uytterhoeven
99dc8e400e serial: sh-sci: Don't call sci_dma_rx_push() if no data has arrived
On receive DMA time-out, avoid calling sci_dma_rx_push() if no data was
transferred by the timed out DMA request.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:33:48 +01:00
Yoshihiro Shimoda
8eadb56d68 serial: sh-sci: Don't kick tx in sci_er_interrupt() when using DMA
If CONFIG_SERIAL_SH_SCI_DMA is enabled, the driver doesn't enable TIE
on SCIF or HSCIF. However, this driver may call sci_tx_interrupt()
in sci_er_interrupt(). After that, the driver cannot care of the
interrupt, and then "irq 109: nobody cared" happens on r8a7791/koelsch
board. This patch fixes the issue.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
[geert] Keep kicking tx when using PIO
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:33:48 +01:00
Geert Uytterhoeven
e6403c112f serial: sh-sci: Don't call sci_rx_interrupt() on error when using DMA
The error handler calls sci_rx_interrupt() to drain the receive FIFO if
an error condition happens.

However, if DMA is enabled on SCIFA or SCIFB, this will call
disable_irq_nosync() twice. Due to this imbalance, the receive interrupt
will never be re-enabled, and reception stops forever.

To fix this, restrict draining the FIFO to PIO mode, and just call
sci_receive_chars() directly.

Inspired by a patch from Yoshihiro Shimoda
<yoshihiro.shimoda.uh@renesas.com>.

Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:33:48 +01:00
Yoshihiro Shimoda
7b39d90184 serial: sh-sci: Fix NULL pointer dereference if HIGHMEM is enabled
This patch fixes an issue that this driver causes a NULL pointer
dereference in the following conditions:
 - CONFIG_HIGHMEM and CONFIG_SERIAL_SH_SCI_DMA are enabled
 - This driver runs on the sci_dma_rx_push()

This issue was caused by virt_to_page(buf) in the sci_request_dma()
because this driver didn't check if the "buf" was valid or not.  So,
this patch uses the "buf" from dma_alloc_coherent() as is, not page.

This patch also fixes a WARNING issue in sci_rx_dma_release():

    WARNING: CPU: 0 PID: 1328 at lib/dma-debug.c:1125 check_unmap+0x444/0x848()
    rcar-dmac e6700000.dma-controller: DMA-API: device driver frees DMA memory with different CPU address [device address=0x000000006dd89000] [size=64 bytes] [cpu alloc address=0x000000016189c000] [cpu free address=0x0000000080000000]

    WARNING: CPU: 1 PID: 1 at drivers/base/dma-mapping.c:334 dma_common_free_remap+0x48/0x6c()
    trying to free invalid coherent area:   (null)

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
[geert] Rebased
[geert] Reworded
[geert] Dropped .rx_chunk, as it's always identical to .rx_buf[0]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:33:48 +01:00
Geert Uytterhoeven
ba172c7045 serial: sh-sci: Use incrementing pointers instead of stack array
There's no need to keep all buffer and DMA pointers on the stack.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:33:48 +01:00
Geert Uytterhoeven
47b0e94a67 serial: sh-sci: Use tty_insert_flip_string() for DMA receive
Switch from using tty_buffer_request_room() and looping over
tty_insert_flip_char() to tty_insert_flip_string().
Keep track of buffer overruns in the icount structure, like
serial_core.c does.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:33:48 +01:00
Geert Uytterhoeven
0533502d25 serial: sh-sci: Pass scatterlist to sci_dma_rx_push()
Currently sci_dma_rx_push() has to find the active scatterlist itself,
but in some cases the caller already knows.

Hence let the caller pass the scatterlist, and introduce a helper to
find the active DMA request while we're at it.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-04 17:33:48 +01:00