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[ Upstream commit 8493eab026 ]
When uart_flush_buffer() is called, the .flush_buffer() callback zeroes
the tx_dma_len field. This may race with the work queue function
handling transmit DMA requests:
1. If the buffer is flushed before the first DMA API call,
dmaengine_prep_slave_single() may be called with a zero length,
causing the DMA request to never complete, leading to messages
like:
rcar-dmac e7300000.dma-controller: Channel Address Error happen
and, with debug enabled:
sh-sci e6e88000.serial: sci_dma_tx_work_fn: ffff800639b55000: 0...0, cookie 126
and DMA timeouts.
2. If the buffer is flushed after the first DMA API call, but before
the second, dma_sync_single_for_device() may be called with a zero
length, causing the transmit data not to be flushed to RAM, and
leading to stale data being output.
Fix this by:
1. Letting sci_dma_tx_work_fn() return immediately if the transmit
buffer is empty,
2. Extending the critical section to cover all DMA preparational work,
so tx_dma_len stays consistent for all of it,
3. Using local copies of circ_buf.head and circ_buf.tail, to make sure
they match the actual operation above.
Reported-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Suggested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Link: https://lore.kernel.org/r/20190624123540.20629-2-geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 93bcefd4c6 upstream.
We disable transmission interrupt (clear SCSCR_TIE) after all data has been transmitted
(if uart_circ_empty(xmit)). While transmitting, if the data is still in the tty buffer,
re-enable the SCSCR_TIE bit, which was done at sci_start_tx().
This is unnecessary processing, wasting CPU operation if the data transmission length is large.
And further, transmit end, FIFO empty bits disabling have also been performed in the step above.
Signed-off-by: Hoan Nguyen An <na-hoan@jinso.co.jp>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8afb1d2c12 upstream.
Commit 40f70c03e3 ("serial: sh-sci: add locking to console write
function to avoid SMP lockup") copied the strategy to avoid locking
problems in conjuncture with the console from the UART8250
driver. Instead using directly spin_{try}lock_irqsave(),
local_irq_save() followed by spin_{try}lock() was used. While this is
correct on mainline, for -rt it is a problem. spin_{try}lock() will
check if it is running in a valid context. Since the local_irq_save()
has already been executed, the context has changed and
spin_{try}lock() will complain. The reason why spin_{try}lock()
complains is that on -rt the spin locks are turned into mutexes and
therefore can sleep. Sleeping with interrupts disabled is not valid.
BUG: sleeping function called from invalid context at /home/wagi/work/rt/v4.4-cip-rt/kernel/locking/rtmutex.c:995
in_atomic(): 0, irqs_disabled(): 128, pid: 778, name: irq/76-eth0
CPU: 0 PID: 778 Comm: irq/76-eth0 Not tainted 4.4.126-test-cip22-rt14-00403-gcd03665c8318 #12
Hardware name: Generic RZ/G1 (Flattened Device Tree)
Backtrace:
[<c00140a0>] (dump_backtrace) from [<c001424c>] (show_stack+0x18/0x1c)
r7:c06b01f0 r6:60010193 r5:00000000 r4:c06b01f0
[<c0014234>] (show_stack) from [<c01d3c94>] (dump_stack+0x78/0x94)
[<c01d3c1c>] (dump_stack) from [<c004c134>] (___might_sleep+0x134/0x194)
r7:60010113 r6:c06d3559 r5:00000000 r4:ffffe000
[<c004c000>] (___might_sleep) from [<c04ded60>] (rt_spin_lock+0x20/0x74)
r5:c06f4d60 r4:c06f4d60
[<c04ded40>] (rt_spin_lock) from [<c02577e4>] (serial_console_write+0x100/0x118)
r5:c06f4d60 r4:c06f4d60
[<c02576e4>] (serial_console_write) from [<c0061060>] (call_console_drivers.constprop.15+0x10c/0x124)
r10:c06d2894 r9:c04e18b0 r8:00000028 r7:00000000 r6:c06d3559 r5:c06d2798
r4:c06b9914 r3:c02576e4
[<c0060f54>] (call_console_drivers.constprop.15) from [<c0062984>] (console_unlock+0x32c/0x430)
r10:c06d30d8 r9:00000028 r8:c06dd518 r7:00000005 r6:00000000 r5:c06d2798
r4:c06d2798 r3:00000028
[<c0062658>] (console_unlock) from [<c0062e1c>] (vprintk_emit+0x394/0x4f0)
r10:c06d2798 r9:c06d30ee r8:00000006 r7:00000005 r6:c06a78fc r5:00000027
r4:00000003
[<c0062a88>] (vprintk_emit) from [<c0062fa0>] (vprintk+0x28/0x30)
r10:c060bd46 r9:00001000 r8:c06b9a90 r7:c06b9a90 r6:c06b994c r5:c06b9a3c
r4:c0062fa8
[<c0062f78>] (vprintk) from [<c0062fb8>] (vprintk_default+0x10/0x14)
[<c0062fa8>] (vprintk_default) from [<c009cd30>] (printk+0x78/0x84)
[<c009ccbc>] (printk) from [<c025afdc>] (credit_entropy_bits+0x17c/0x2cc)
r3:00000001 r2:decade60 r1:c061a5ee r0:c061a523
r4:00000006
[<c025ae60>] (credit_entropy_bits) from [<c025bf74>] (add_interrupt_randomness+0x160/0x178)
r10:466e7196 r9:1f536000 r8:fffeef74 r7:00000000 r6:c06b9a60 r5:c06b9a3c
r4:dfbcf680
[<c025be14>] (add_interrupt_randomness) from [<c006536c>] (irq_thread+0x1e8/0x248)
r10:c006537c r9:c06cdf21 r8:c0064fcc r7:df791c24 r6:df791c00 r5:ffffe000
r4:df525180
[<c0065184>] (irq_thread) from [<c003fba4>] (kthread+0x108/0x11c)
r10:00000000 r9:00000000 r8:c0065184 r7:df791c00 r6:00000000 r5:df791d00
r4:decac000
[<c003fa9c>] (kthread) from [<c00101b8>] (ret_from_fork+0x14/0x3c)
r8:00000000 r7:00000000 r6:00000000 r5:c003fa9c r4:df791d00
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Daniel Wagner <daniel.wagner@siemens.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 090fa4b0dc ]
The sci_ports[] array is indexed using a value derived from the
"serialN" alias in DT, which may lead to an out-of-bounds access.
Fix this by adding a range check.
Note that the array size is defined by a Kconfig symbol
(CONFIG_SERIAL_SH_SCI_NR_UARTS), so this can even be triggered using a
legitimate DTB.
Fixes: 97ed9790c5 ("serial: sh-sci: Remove unused platform data capabilities field")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7842055bfc upstream.
When the TTY buffers fill up to the configured maximum, a system lockup
occurs:
[ 598.820128] INFO: rcu_preempt detected stalls on CPUs/tasks:
[ 598.825796] 0-...!: (1 GPs behind) idle=5a6/2/0 softirq=1974/1974 fqs=1
[ 598.832577] (detected by 3, t=62517 jiffies, g=296, c=295, q=126)
[ 598.838755] Task dump for CPU 0:
[ 598.841977] swapper/0 R running task 0 0 0 0x00000022
[ 598.849023] Call trace:
[ 598.851476] __switch_to+0x98/0xb0
[ 598.854870] (null)
This can be prevented by doing a dummy read of the RX data register.
This issue affects both HSCIF and SCIF ports. Reported for R-Car H3 ES2.0;
reproduced and fixed on H3 ES1.1. Probably affects other R-Car platforms
as well.
Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: stable <stable@vger.kernel.org>
Tested-by: Nguyen Viet Dung <dung.nguyen.aj@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 7464779fa8 ]
If a port has no dma channel defined in the device tree, then
don't attempt to allocate a dma channel for the port.
Also suppress the warning message concerning the failure to allocate
a dma channel. Continue to emit the warning message if a dma
channel is defined but cannot be allocated.
Signed-off-by: Andy Lowe <andy_lowe@mentor.com>
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The kstrtol() function returns -ERANGE as well as -EINVAL so these tests
are not enough. It's not a super serious bug, but my static checker
correctly complains that the "r" variable might be used uninitialized.
Fixes: 5d23188a47 ("serial: sh-sci: make RX FIFO parameters tunable via sysfs")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The commit below changed a function call from
dma_request_slave_channel_compat() to dma_request_slave_channel(), but
forgot to update the printed failure message.
Fixes: 219fb0c143 ("serial: sh-sci: Remove the platform data dma slave rx/tx channel IDs")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
uart_register_driver call binds the driver to a specific device
node through tty_register_driver call. This should typically
happen during device probe call.
In a multiplatform scenario, it is possible that multiple serial
drivers are part of the kernel. Currently the driver registration fails
if multiple serial drivers with overlapping major/minor numbers are
included.
Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If DMA is enabled and used, a burst of old data may be seen on the
serial console during "poweroff" or "reboot". uart_flush_buffer()
clears the circular buffer, but sci_port.tx_dma_len is not reset.
This leads to a circular buffer overflow, dumping (UART_XMIT_SIZE -
sci_port.tx_dma_len) bytes.
To fix this, add a .flush_buffer() callback that resets
sci_port.tx_dma_len.
Inspired by commit 31ca2c63fd ("tty/serial: atmel: fix race
condition (TX+DMA)").
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If a UART has dedicated RTS/CTS pins, and hardware control flow is
disabled (or AUTORTS is not yet effective), changing any serial port
configuration deasserts RTS, as .set_termios() calls sci_init_pins().
To fix this, consider the current (AUTO)RTS state when (re)initializing
the pins. Note that for SCIFA/SCIFB, AUTORTS needs explicit
configuration of the RTS# pin function, while (H)SCIF handles this
automatically.
Fixes: d2b9775d79 ("serial: sh-sci: Correct pin initialization on (H)SCIF")
Fixes: e9d7a45a03 ("serial: sh-sci: Add pin initialization for SCIFA/SCIFB")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
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>
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 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>
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>
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>
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>
