When changing hardware control flow for a UART with dedicated RTS/CTS
pins, the new AUTORTS state is not immediately reflected in the
hardware, but only when RTS is raised. However, the serial core does
not call .set_mctrl() after .set_termios(), hence AUTORTS may only
become effective when the port is closed, and reopened later.
Note that this problem does not happen when manually using stty to
change CRTSCTS, as AUTORTS will work fine on next open.
To fix this, call .set_mctrl() from .set_termios() when dedicated
RTS/CTS pins are present, to refresh the AUTORTS or RTS state.
This is similar to what other drivers supporting AUTORTS do (e.g.
omap-serial).
Reported-by: Baumann, Christoph (C.) <cbaumann@visteon.com>
Fixes: 33f50ffc25 ("serial: sh-sci: Fix support for hardware-assisted RTS/CTS")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the .set_termios() callback resets the UART, it first waits (busy
loops) until all characters in the transmit FIFO have been transmitted,
to prevent a port configuration change from impacting these characters.
However, if the UART has dedicated RTS/CTS hardware flow control
enabled, these characters may have been stuck in the FIFO due to CTS not
being asserted by the remote side.
- When a new user opens the port, .set_termios() is called while
transmission is still disabled, leading to an infinite loop:
NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s!
- When an active user changes port configuration without waiting for
the draining of the transmit FIFO, this may also block indefinitely,
until CTS is asserted by the remote side.
This has been observed with SCIFA (on r8a7740/armadillo), and SCIFB and
HSCIF (on r8a7791/koelsch).
To fix this, remove the code that waits for the draining of the transmit
FIFO.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fixes an issue that kernel panic happens when DMA is enabled
and we press enter key while the kernel booting on the serial console.
* An interrupt may occur after sci_request_irq().
* DMA transfer area is initialized by setup_timer() in sci_request_dma()
and used in interrupt.
If an interrupt occurred between sci_request_irq() and setup_timer() in
sci_request_dma(), DMA transfer area has not been initialized yet.
So, this patch changes the order of sci_request_irq() and
sci_request_dma().
Fixes: 73a19e4c03 ("serial: sh-sci: Add DMA support.")
Signed-off-by: Takatoshi Akiyama <takatoshi.akiyama.kj@ps.hitachi-solutions.com>
[Shimoda changes the commit log]
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1. Do not set the RX trigger level for software timeout devices on reset;
there is no timeout by default, and data will rot.
2. Do set the RX trigger level for hardware timeout devices when set
via sysfs attribute.
Fixes SCIFA-type serial consoles.
Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Allows tuning of the RX FIFO fill threshold and timeout. (The latter is
only applicable to SCIFA and SCIFB).
Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Implements support for FIFO fill thresholds greater than one with software
timeout.
This mechanism is not possible (or at least not useful) on SCIF family
hardware other than SCIFA and SCIFB because they do not support turning off
the DR hardware timeout interrupt separately from the RI interrupt.
Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Sets reasonable trigger defaults for the various SCIF variants.
Also corrects the FIFO size for SH7705-style ports.
Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As the function header of sci_parse_dt() is split in an unusual way,
"git diff" gets confused when changes to the body of the function are
made, and attributes them to the wrong function.
Reformat the function header to fix this.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
SCI instances found in SH SoCs have different spacing between registers
depending on the SoC. The platform data contains a regshift field that
tells the driver by how many bits to shift the register offset to
compute its address. We can compute the regshift value automatically
based on the memory resource size, there's no need to pass the value
through platform data.
Fix the sh7750 SCI and sh7760 SIM port memory resources length to ensure
proper computation of the regshift value.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The field isn't set by any platform but is only used internally in the
driver to hold data parsed from DT. Move it to the sci_port structure.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The sh-sci driver implements manual break debouncing for a few SH
platforms by reading the value of the RX pin port register. This feature
is optional and the driver considers all negative or zero values of the
platform data port_reg field as invalid. As the four platforms that set
the field to a register address all use an address higher than
0x7fffffff, the driver will always consider the value as invalid and
never perform debouncing. The feature is unused, remove it.
Debouncing could be implemented properly in the future using the pinctrl
and GPIO APIs if desired.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Only SH platforms still use platform data for the sh-sci, and none of
them declare DMA channels connected to the SCI. Remove the corresponding
platform data fields and simplify the driver accordingly.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The fifo size, overrun register and mask, sampling rate mask and error
mask all depend on the port type only and don't need to be computed at
runtime. Add them to the sci_port_parameters structure.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The driver modifies platform data for internal purpose only. Fix that
and make the platform data structure const.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Turn the regmap two-dimensional array to an array of port parameters and
store a pointer to the port parameters in the sci_port structure. This
will allow handling additional port type dependent parameters.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Even though most of its registers are 8-bit wide, the IRDA has two
16-bit registers that make it a 16-bit peripheral and not a 8-bit
peripheral with addresses shifted by one. Fix the registers offset in
the driver and the platform data regshift value.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The UPF_BOOT_AUTOCONF platform data flag is set by all platforms,
hardcode it.
The UPF_IOREMAP flag is set by a single SH platform and thus needs to be
kept. However, for ARM platforms, we can base the decision on whether an
OF node is present and bypass the platform data flags completely.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Transmit Enable and Receive Enable bits are set in the scscr field
of all instances of the sh-sci platform data. Set them in the driver
directly to prepare for their removal from platform data.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the call to kasprintf() returns a NULL pointer, function
sci_request_irq() frees the preallocated memory and returns 0 is
returned. Because 0 means no error, the caller of sci_request_irq()
will keep going, and the freed memory may be used or freed again. To
avoid the above issue, this patch assigns "-ENOMEM" to the return
variable ret.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188691
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While spin is already locked, serial output request causes the deadlock,
because serial output process also tries to lock the spin.
This patch removes serial output with spin locked.
Signed-off-by: Takatoshi Akiyama <takatoshi.akiyama.kj@ps.hitachi-solutions.com>
Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Check for uart_ops structures that are only stored in the ops field of a
uart_port structure. This field is declared const, so uart_ops structures
that have this property can be declared as const also.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct uart_ops i@p = { ... };
@ok@
identifier r.i;
struct uart_port e;
position p;
@@
e.ops = &i@p;
@bad@
position p != {r.p,ok.p};
identifier r.i;
struct uart_ops e;
@@
e@i@p
@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
struct uart_ops i = { ... };
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Make sure the transmitter and receiver are stopped when shutting down
the port, and related interrupts are disabled.
Without this:
- New input data may be received into the RX FIFO, possibly
triggering a new RX DMA completion,
- Transfers will still be enabled on a subsequent startup of the UART,
before the UART's FIFOs have been reset, causing reading of stale
data.
Inspired by a patch in the BSP by Koji Matsuoka
<koji.matsuoka.xm@renesas.com>.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add the missing timeout bit definition for (H)SCIF.
Clear the timeout and overrun flag bits during UART reset, cfr. the
initialization flowchart in the datasheet.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Setting the FIFO reset bits is not sufficient to reset the RX FIFO.
After this the status register's RDF flag bit may still be set, causing
the reception of one stale byte of data.
To fix this, clear all status flag bits related to reception, error, and
break handling, cfr. the initialization flowchart in the datasheet.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
FIFO reset is done in sci_reset(), called from sci_set_termios(), while
sci_start_tx() and sci_start_rx() are called before, from sci_startup().
However, starting transfers before the UART's FIFOs have been reset may
cause reading of stale data.
Remove the calls to sci_start_tx() and sci_start_rx() from sci_startup()
to fix this.
Transfers are still started when needed:
- sci_start_rx() is called from sci_set_termios() after FIFO reset, if
the CREAD flag is set,
- sci_start_tx() is called from uart_change_speed() immediately
thereafter, if transmission is enabled.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for indicating the availability of dedicated lines for
RTS/CTS hardware flow control, using the standard "uart-has-rtscts" DT
property.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The existing support for hardware-assisted RTS/CTS is rudimentary and
doesn't work.
Add support for hardware-assisted RTS/CTS hardware flow control for the
(H)SCIF, SCIFA, and SCIFB variants.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Before, the driver relied on initialization by the boot loader, or by
implicit reset state.
Note that unlike on (H)SCIF, the RTS/CTS bits exist only if dedicated
RTS/CTS pins are available, which depends on the SoC and UART instance.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Correct pin initialization on (H)SCIF:
- RTS must be deasserted (it's active low),
- SCK must be an input, as it may be used as the optional external
clock input.
Initial pin configuration must always be done:
- Regardless of the presence of dedicated RTS and CTS pins: if the
register exists, the RTS/CTS bits exist, too,
- Regardless of hardware flow control being enabled or not: RTS must
be deasserted.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Replace open-coded variants of sci_getreg() by function calls, and drop
intermediate variables where appropriate.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Enhance the Renesas SCI UART driver to add support for GPIO-controlled
modem lines (CTS, DSR, DCD, RNG, RTS, DTR), using the serial_mctrl_gpio
helpers.
GPIO-controlled modem lines can be used when dedicated modem lines are
not available. Invalid configurations specifying both GPIO RTS/CTS and
dedicated RTS/CTS are rejected.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Documentation/serial/driver clearly states:
If the port does not support CTS, DCD or DSR, the driver should
indicate that the signal is permanently active.
Hence always set TIOCM_CTS, as we currently don't look at the CTS
hardware line state at all.
FWIW, this fixes the transmit path when hardware-assisted flow control
is enabled, and userspace enables CRTSCTS.
The receive path is still broken, as RTS is never asserted.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As of commit 2eaa790989 ("earlycon: Use common framework for
earlycon declarations") it is no longer needer to specify both
EARLYCON_DECLARE() and OF_EARLYCON_DECLARE().
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for sparse variable sampling rates on SCIFA and SCIFB.
According to the datasheet, sampling rate 1/5 needs a small quirk to
avoid corrupting the first byte received.
This increases the range and accuracy of supported baud rates.
E.g. on r8a7791/koelsch:
- Supports now 134, 150, and standard 500000-4000000 bps,
- Perfect match for 134, 150, 500000, 1000000, 2000000, and 4000000
bps,
- Accuracy has increased for most standard bps values.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Replace the single sampling rate and special handling for HSCIF's
variable sampling rates by a bitmask and a custom iterator.
This prepares for the advent of SCIFA/SCIFB's sparse variable sampling
rates.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On SCIx variants different from HSCIF, the bit rate is equal to the
sampling clock rate divided by half the sampling rate. Currently this is
handled by dividing the sampling rate by two, which was OK as it was
always even.
Replace halving the sampling rate by premultiplying the base clock
frequency by 2, to accommodate odd sampling rates on SCIFA/SCIFB later.
Replace the shift value in the BRG divider calculation by a
premultiplication of the base clock frequency too, for consistency.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
SCIFA and SCIFB have additional bit rate config bits in the Serial Mode
Register. Don't touch them when using the port as a serial console, as
we rely on the boot loader to have configured the serial port config.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
"earlyprintk" is architecture specific option.
General "earlycon" option support is much better.
Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
[uli: preserve other SCSCR bits when asserting RE and TE]
Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
[geert: rewording, #ifdef rework]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The BSP team noticed that there is spin/mutex lock issue on sh-sci when
CPUFREQ is used. The issue is that the notifier function may call
mutex_lock() while the spinlock is held, which can lead to a BUG().
This may happen if CPUFREQ is changed while another CPU calls
clk_get_rate().
Taking the spinlock was added to the notifier function in commit
e552de2413 ("sh-sci: add platform device private data"), to
protect the list of serial ports against modification during traversal.
At that time the Common Clock Framework didn't exist yet, and
clk_get_rate() just returned clk->rate without taking a mutex.
Note that since commit d535a2305f ("serial: sh-sci: Require a
device per port mapping."), there's no longer a list of serial ports to
traverse, and taking the spinlock became superfluous.
To fix the issue, just remove the cpufreq notifier:
1. The notifier doesn't work correctly: all it does is update stored
clock rates; it does not update the divider in the hardware.
The divider will only be updated when calling sci_set_termios().
I believe this was broken back in 2004, when the old
drivers/char/sh-sci.c driver (where the notifier did update the
divider) was replaced by drivers/serial/sh-sci.c (where the
notifier just updated port->uartclk).
Cfr. full-history-linux commits 6f8deaef2e9675d9 ("[PATCH] sh: port
sh-sci driver to the new API") and 3f73fe878dc9210a ("[PATCH]
Remove old sh-sci driver").
2. On modern SoCs, the sh-sci parent clock rate is no longer related
to the CPU clock rate anyway, so using a cpufreq notifier is
futile.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Geert writes:
Summary:
- Clean up the naming of clocks in the sh-sci driver and its DT bindings,
- Add support for the optional external clock on (H)SCI(F), where this pin
can serve as a clock input,
- Add support for the optional clock sources for the Baud Rate
Generator for External Clock (BRG), as found on some SCIF variants
and on HSCIF.
All platforms that used to define an sci_fck clock have now switched to
the fck name. Remove the fallback code.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for using the Baud Rate Generator for External Clock (BRG), as
found on some SCIF and HSCIF variants, to provide the sampling clock.
This can improve baud rate range and accuracy.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for using the SCIx clock pin "(H)SCK" as an external clock
input on (H)SCI(F), providing the sampling clock.
Note that this feature is not yet supported on the select SCIFA variants
that also have it (e.g. sh7723, sh7724, and r8a7740).
On (H)SCIF variants with an External Baud Rate Generator (BRG), the
BRG Clock Select Register must be configured for the external clock.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Refactor the clock and baud rate parameter code to ease adding support
for multiple sampling clock sources.
sci_scbrr_calc() now returns the bit rate error, so it can be compared
to the bit rate error using other sampling clock sources.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The "renesas,scif" compatible value is currently used for the SCIF
variant in all Renesas SoCs of the R-Car family. However, the variant
used in the R-Car family is not the common "SH-4(A)" variant, but a
derivative with added "Baud Rate Generator for External Clock" (BRG),
which is also present in sh7734.
Use the family-specific SCIF compatible values for R-Car Gen1, Gen2, and
Gen3 SoCs to differentiate. The "renesas,scif" compatible value can
still be used as a common denominator for SCIF variants with the
"SH-4(A)" register layout (i.e. ignoring the "Serial Extension Mode
Register" (SCEMR) and the new BRG-specific registers).
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The "renesas,scif" compatible value is currently used for the SCIF
variant in all Renesas SoCs of the R-Car and RZ families. However, the
variant used in the RZ family is not the common "SH-4(A)" variant, but
the "SH-2(A) with FIFO data count register" variant, as it has the
"Serial Extension Mode Register" (SCEMR), just like on sh7203, sh7263,
sh7264, and sh7269.
Use the (already documented) SoC-specific "renesas,scif-r7s72100"
compatible value to differentiate. The "renesas,scif" compatible value
can still be used as a common denominator for SCIF variants with the
"SH-4(A)" register layout (i.e. ignoring the SCEMR register).
Note that currently both variants are treated the same, but this may
change if support for the SCEMR register is ever added.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
