Until now only the Exynos SoCs could use the serial driver via the
device tree. This patch adds compatible properties for the other
supported SoCs as well.
Tested on a s3c2416 based machine.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Certain tty line discipline implementations such slip and bluetooth hci invoke
the serial core uart_write() api in their write_wakeup callback. This leads to
a soft lockup with samsung serial driver since the uart port lock is taken in
the driver's interrupt handler and uart_write() attempts to take the same lock
again.
Fix this issue by releasing the uart port lock before the call to
uart_write_wakeup() in the tx handler. Also move the spin-lock/unlock sequence
from s3c64xx_serial_handle_irq() function into the tx and rx irq handlers so
that this change is applicable to s3c24xx platforms as well.
Reported-by: Kyungmin Park <kyungmin.park@samsung.com>
Reported-by: Hyeonkook Kim <hk619.kim@samsung.com>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add XR17D15x devices to the exar_handle_irq override: they have the
same extra interrupt register that could fire and never be serviced by
the standard handle_irq.
Signed-off-by: Matt Schulte <matts@commtech-fastcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
set_termios may be invoked before the former data transfer is completed.
Block until the tranfer is done.
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Only we meet the following conditions, we can enable the DMA support for
auart:
(1) We enable the DMA support in the dts file, such as
arch/arm/boot/dts/imx28.dtsi.
(2) We enable the hardware flow control.
(3) We use the mx28, not the mx23. Due to hardware bug(see errata: 2836),
we can not add the DMA support to mx23.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current mxs-auart driver is used for both mx23 and mx28.
But in mx23, the DMA has a bug(see errata:2836). We can not add the
DMA support in mx23, but we can add DMA support to auart in mx28.
So in order to add the DMA support for the auart in mx28, we should
distinguish the distinguish SOCs.
This patch adds a new platform_device_id table and a inline function
is_imx28_auart() to distinguish the mx23 and mx28.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Allows overriding default methods serial_in/serial_out.
In such platform specific replacement it is possible to use
other regshift, biased register offset, any other manipulation
that is not covered with common default methods.
Overriding default methods may be useful for platforms which got
serial peripheral with registers represented in big endian.
In this situation and assuming that 32 bit operations / alignment
is required then it may be useful to swab words before/after
accessing the serial registers.
Signed-off-by: Noam Camus <noamc@ezchip.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In the previous commit, console write function (serial_console_write)
is changed to disable SCI interrupts while printing console strings.
This introduces possible race cases in the serial startup / shutdown
functions on SMP systems.
This patch fixes the sh-sci in the same way as commit 9ec1882df2
(tty: serial: imx: console write routing is unsafe on SMP, from
Xinyu Chen <xinyu.chen@freescale.com>, 2012-08-27) did.
There could be several consumers of the console,
* the kernel printk
* the init process using /dev/kmsg to call printk to show log
* shell, which opens /dev/console and writes with sys_write()
The shell goes into the normal UART open() and write() system calls,
while the other two go into the console operations. The open() call
invokes serial startup function (sci_startup), which will write to
the SCSCR register (to enable or disable SCI interrupts) without any
locking. This will conflict with the console serial function.
Add spinlock protections in sci_startup() and sci_shutdown() properly.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Symptom:
When entering the suspend with Android logcat running, printk() call
gets stuck and never returns. The issue can be observed at printk()s
on nonboot CPUs when going to offline with their interrupts disabled,
and never seen at boot CPU (core0 in our case).
Details:
serial_console_write() lacks of appropriate spinlock handling.
In SMP systems, as long as sci_transmit_chars() is being processed
at one CPU core, serial_console_write() can stuck at the other CPU
core(s), when it tries to access to the same serial port _without_
a proper locking. serial_console_write() waits for the transmit FIFO
getting empty, while sci_transmit_chars() writes data to the FIFO.
In general, peripheral interrupts are routed to boot CPU (core0) by
Linux ARM standard affinity settings. SCI(F) interrupts are handled
by core0, so sci_transmit_chars() is processed on core0 as well.
When logcat is running, it writes enormous log data to the kernel at
every moment, forever. So core0 can repeatedly continue to process
sci_transmit_chars() in its interrupt handler, which eventually makes
the other CPU core(s) stuck at serial_console_write().
Looking at serial/8250.c, this is a known console write lockup issue
with SMP kernels. Fix the sh-sci driver in the same way 8250.c does.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
About FIFO count, there are two variants of SCIFs which show
a) TX count in upper, RX count in lower byte of FDR register
b) TX count in TFDR register, RX count in RFDR register
Common SCIFB regmap in current source code is defined as "a".
At least 7372 and 73a0 HW manual say their SICFB are "b".
This patch alters the definition to "b", considering the current
one has come from a mistake. The reason is as follows.
The flag SCIFB sh-sci driver means it has 256 byte FIFO.
The count is from 0(empty) to 256(full), that makes 9-bit.
Because FDR is 16-bit register, it can not hold two 9-bits.
That's why, SCIFB can not be "a".
Signed-off-by: Takashi Yoshii <takashi.yoshii.zj@renesas.com>
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Current mask 0xff to SCTFDR/RFDR damages SCIFB, because the
registers on SCIFB have 9-bit data (0 to 256).
This patch changes the mask according to port->fifosize.
Though I'm not sure if the mask is really needed (I don't know if
there are variants which have non-zero upper bits), it is safer.
Signed-off-by: Takashi Yoshii <takashi.yoshii.zj@renesas.com>
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Support prescaler 1/16 and 1/64, in addition to current 1 and 1/4.
Supporting below 2400bps was dropped long time ago in mainline.
Since then, setting lower rate has been resulting in erroneous
register value, without indicating any errors through API.
This patch adds more prescaler to support lower rates again.
This still doesn't check range, but we won't hit the case because
even 50bps at 48MHz clock is now supported.
Signed-off-by: Takashi Yoshii <takashi.yoshii.zj@renesas.com>
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Heiko Stübner
Thomas Abraham
Matt Schulte
Sonic Zhang
Bill Pemberton
Greg Kroah-Hartman
Huang Shijie
Noam Camus
Shinya Kuribayashi
Takashi Yoshii