Commit Graph

296 Commits

Author SHA1 Message Date
Fabien Lahoudere
db0a196bd8 serial: imx: Add DMA buffer configuration via DT
In order to optimize serial communication (performance/throughput VS
latency), we may need to tweak DMA period number and size. This adds
DT properties to configure those values before initialising DMA.
The defaults will stay the same as before.

[update documentation and commit message, rebase to current master,
switch back to DT instead of sysfs]

Signed-off-by: Fabien Lahoudere <fabien.lahoudere@collabora.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20210430175038.103226-2-sebastian.reichel@collabora.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-04 15:11:16 +02:00
Johan Hovold
18ee37e138 serial: drop irq-flags initialisations
There's no need to initialise irq-flags variables before saving the
interrupt state.

Drop the redundant initialisations from drivers that got this wrong.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210519092541.10137-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-20 16:24:05 +02:00
Johan Hovold
9baedb7bae serial: imx: drop workaround for forced irq threading
Force-threaded interrupt handlers used to run with interrupts enabled,
something which could lead to deadlocks in case a threaded handler
shared a lock with code running in hard interrupt context (e.g. timer
callbacks) and did not explicitly disable interrupts.

This was specifically the case for serial drivers that take the port
lock in their console write path as printk can be called from hard
interrupt context also with forced threading ("threadirqs").

Since commit 81e2073c17 ("genirq: Disable interrupts for force
threaded handlers") interrupt handlers always run with interrupts
disabled on non-RT so that drivers no longer need to do handle this.

Drop the now obsolete workaround added by commit 33f16855dc ("tty:
serial: imx: fix potential deadlock").

Cc: Sam Nobs <samuel.nobs@taitradio.com>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210322111036.31966-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-23 10:32:44 +01:00
Jiri Slaby
f751ae1cbb tty: imx, use ms_to_ktime
This really eliminates multiplications from the assembly. I would have
thought they are optimized by inlining ktime_set, but not on x86_64 with
gcc 10.

Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210302062214.29627-10-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10 09:34:06 +01:00
Zheng Yongjun
5b10956483 tty/serial/imx: convert comma to semicolon
Replace a comma between expression statements by a semicolon.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Link: https://lore.kernel.org/r/20201214133719.3893-1-zhengyongjun3@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-28 16:10:45 +01:00
Fabio Estevam
4661f46e50 serial: imx: Move imx_uart_probe_dt() content into probe()
Now that the driver only probes via devicetree, we can move the
content of imx_uart_probe_dt() directly into imx_uart_probe() to
make the code simpler.

Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20201209214712.15247-1-festevam@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-10 16:24:52 +01:00
Fabio Estevam
603012f78a serial: imx: Remove unneeded of_device_get_match_data() NULL check
Since 5.10-rc1 i.MX is a devicetree-only platform and the NULL check on
of_device_get_match_data() is no longer needed.

This check was only needed when this driver supported both DT and non-DT
platforms.

Remove the unneeded of_device_get_match_data() NULL check.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20201126124643.3371-1-festevam@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-09 19:48:10 +01:00
Mingrui Ren
aef1b6a279 tty/serial/imx: Enable TXEN bit in imx_poll_init().
As described in Documentation, poll_init() is called by kgdb to initialize
hardware which supports both poll_put_char() and poll_get_char().

It's necessary to enable TXEN bit, otherwise, it will cause hardware fault
and kernel panic when calling imx_poll_put_char().

Generally, if use /dev/ttymxc0 as kgdb console as well as system
console, ttymxc0 is initialized early by system console which does enable
TXEN bit.But when use /dev/ttymxc1 as kgbd console, ttymxc1 is only
initialized by imx_poll_init() cannot enable the TXEN bit, which will
cause kernel panic.

Signed-off-by: Mingrui Ren <jiladahe1997@gmail.com>
Link: https://lore.kernel.org/r/20201202072543.151-1-972931182@qq.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-04 16:54:20 +01:00
Greg Kroah-Hartman
3b3e230924 Linux 5.10-rc5
-----BEGIN PGP SIGNATURE-----
 
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 QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGTSYH/ifRBlaxy5UiHFc0
 2zdR7pkjWrYfDTTT3sazIAhdlzzcfnkUqgFxOP45F4ZIqeTzunH3sUY+5UlT9IX7
 liUgnLxQ/1R9Gx8kPGQfu+tLCey78xVFydGsqJoW9sPRw2R+apMdGGa/lOrk+OXz
 DXIN+dDnGFqwCCNJpK+rxQQhFf++IPpSI8z6Y23moOFhsDZrEziHuVFy2FGyRM6z
 prZ/us/tcobE8ptCk1RmOxLoJ1DR6UxpA2vLimTE+JD8siOsSWPbjE0KudnWCnd5
 BLqIjrsPJbSxyuzzK3v9dnO5wMv7tMDuMIuYM/MQTXDttNwtsqt/aP6gdnUCym7N
 5eHEj5g=
 =MuO1
 -----END PGP SIGNATURE-----

Merge 5.10-rc5 into tty-next

We need the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-23 08:25:08 +01:00
Fabio Estevam
660beb0ffd serial: imx: Remove unused .id_table support
Since 5.10-rc1 i.MX is a devicetree-only platform and the existing
.id_table support in this driver was only useful for old non-devicetree
platforms.

Get rid of the .id_table since it is no longer used.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20201115110341.22761-1-festevam@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-18 13:02:38 +01:00
Fabio Estevam
1f78ae9979 serial: imx: Remove unused platform data support
Since 5.10-rc1 i.MX is a devicetree-only platform and the existing
platform data support in this driver was only useful for old non-devicetree
platforms.

Get rid of the platform data support since it is no longer used.

Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20201110214840.16768-1-festevam@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-12 09:44:22 +01:00
Fugang Duan
e67c139c48 tty: serial: imx: keep console clocks always on
For below code, there has chance to cause deadlock in SMP system:
Thread 1:
clk_enable_lock();
pr_info("debug message");
clk_enable_unlock();

Thread 2:
imx_uart_console_write()
	clk_enable()
		clk_enable_lock();

Thread 1:
Acuired clk enable_lock -> printk -> console_trylock_spinning
Thread 2:
console_unlock() -> imx_uart_console_write -> clk_disable -> Acquite clk enable_lock

So the patch is to keep console port clocks always on like
other console drivers.

Fixes: 1cf93e0d54 ("serial: imx: remove the uart_console() check")
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20201111025136.29818-1-fugang.duan@nxp.com
Cc: stable <stable@vger.kernel.org>
[fix up build warning - gregkh]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-12 09:39:53 +01:00
Sam Nobs
33f16855dc tty: serial: imx: fix potential deadlock
Enabling the lock dependency validator has revealed
that the way spinlocks are used in the IMX serial
port could result in a deadlock.

Specifically, imx_uart_int() acquires a spinlock
without disabling the interrupts, meaning that another
interrupt could come along and try to acquire the same
spinlock, potentially causing the two to wait for each
other indefinitely.

Use spin_lock_irqsave() instead to disable interrupts
upon acquisition of the spinlock.

Fixes: c974991d26 ("tty:serial:imx: use spin_lock instead of spin_lock_irqsave in isr")
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sam Nobs <samuel.nobs@taitradio.com>
Link: https://lore.kernel.org/r/1604955006-9363-1-git-send-email-samuel.nobs@taitradio.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-12 09:32:49 +01:00
Matthias Schiffer
edd64f3079 tty: serial: imx: disable TXDC IRQ in imx_uart_shutdown() to avoid IRQ storm
The IPG clock is disabled at the end of imx_uart_shutdown(); we really
don't want to run any IRQ handlers after this point.

At least on i.MX8MN, the UART will happily continue to generate interrupts
even with its clocks disabled, but in this state, all register writes are
ignored (which will cause the shadow registers to differ from the actual
register values, resulting in all kinds of weirdness).

In a transfer without DMA, this could lead to the following sequence of
events:

- The UART finishes its transmission while imx_uart_shutdown() is run,
  triggering the TXDC interrupt (we can trigger this fairly reliably by
  writing a single byte to the TTY and closing it right away)
- imx_uart_shutdown() finishes, disabling the UART clocks
- imx_uart_int() -> imx_uart_transmit_buffer() -> imx_uart_stop_tx()

imx_uart_stop_tx() should now clear UCR4_TCEN to disable the TXDC
interrupt, but this register write is ineffective. This results in an
interrupt storm.

To disable all interrupts in the same place, and to avoid setting UCR4
twice, clearing UCR4_OREN is moved below del_timer_sync() as well; this
should be harmless.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Link: https://lore.kernel.org/r/20200925082412.12960-1-matthias.schiffer@ew.tq-group.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-30 14:31:04 +02:00
Ye Bin
5f0e708c8d serial: imx: Delete duplicated argument to '|' in imx_uart_probe
When calculate "ucr1" UCR1_TRDYEN is duplicate.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20200903062401.692442-1-yebin10@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-04 17:11:59 +02:00
Fugang Duan
0db4f9b91c tty: serial: imx: enable imx serial console port as module
Add support for building i.MX serial driver as module.

The changes of the patch:
- imx console driver can be built as module.
- move out earlycon code to separated driver like imx_earlycon.c,
  and imx earlycon driver only support build-in.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20200724070815.11445-2-fugang.duan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29 17:10:59 +02:00
Ahmad Fatoum
bd78ecd605 serial: imx: use hrtimers for rs485 delays
This patch imitates 6e0a5de213 ("serial: 8250: Use hrtimers for
rs485 delays") in replacing the previously used classic timers
with hrtimers. The old way provided a too coarse resolution on
systems with configs of less than 1000 HZ.

Use of hrtimers addresses this and can be easily extended to
support microsecond resolution in future when support
for this arrives upstream.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.kernel.org/r/20200714093012.21621-3-uwe@kleine-koenig.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-21 21:08:11 +02:00
Uwe Kleine-König
cb1a609236 serial: imx: implement rts delaying for rs485
This adds support for delays between assertion of RTS (which is supposed
to enable the rs485 transmitter) and sending as well as between the last
send char and deassertionof RTS.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20200714093012.21621-2-uwe@kleine-koenig.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-21 21:08:10 +02:00
Andy Shevchenko
dfe51d9777 Revert "serial: imx: Initialize lock for non-registered console"
This reverts commit 8f065acec7.

There has been a quick fix against uninitialised lock revealed by
the commit f743061a85 ("serial: core: Initialise spin lock before use
in uart_configure_port()"). Since we have now better fix in serial core,
this may be safely reverted.

Fixes: 8f065acec7 ("serial: imx: Initialize lock for non-registered console")
Depends-on: f743061a85 ("serial: core: Initialise spin lock before use in uart_configure_port()")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200711135346.71171-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-21 18:21:49 +02:00
Matthias Schiffer
d1d996afbd tty: serial: imx: clear Ageing Timer Interrupt in handler
The AGTIM flag must be cleared explicitly, otherwise the IRQ handler
will be called in an endless loop.

Fortunately, this issue currently doesn't affect mainline kernels in
practice, as the the RX FIFO trigger level is set to 1 in UFCR. When
setting the trigger level to a higher number, the issue is trivially
reproducible by any RX without DMA that doesn't fill the FIFO up to the
configured level.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Link: https://lore.kernel.org/r/20200528154747.14201-1-matthias.schiffer@ew.tq-group.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-29 13:00:54 +02:00
Andy Shevchenko
8f065acec7 serial: imx: Initialize lock for non-registered console
The commit a3cb39d258
("serial: core: Allow detach and attach serial device for console")
changed a bit logic behind lock initialization since for most of the console
driver it's supposed to have lock already initialized even if console is not
enabled. However, it's not the case for Freescale IMX console.

Initialize lock explicitly in the ->probe().

Note, there is still an open question should or shouldn't not this driver
register console properly.

Fixes: a3cb39d258 ("serial: core: Allow detach and attach serial device for console")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200525105952.13744-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-27 10:55:35 +02:00
Lukas Wunner
c150c0f362 serial: Allow uart_get_rs485_mode() to return errno
We're about to amend uart_get_rs485_mode() to support a GPIO pin for
rs485 bus termination.  Retrieving the GPIO descriptor may fail, so
allow uart_get_rs485_mode() to return an errno and change all callers
to check for failure.

The GPIO descriptor is going to be stored in struct uart_port.  Pass
that struct to uart_get_rs485_mode() in lieu of a struct device and
struct serial_rs485, both of which are directly accessible from struct
uart_port.

A few drivers call uart_get_rs485_mode() before setting the struct
device pointer in struct uart_port.  Shuffle those calls around where
necessary.

[Heiko Stuebner did the ar933x_uart.c portion, hence his Signed-off-by.]

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/271e814af4b0db3bffbbb74abf2b46b75add4516.1589285873.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15 14:47:05 +02:00
Anson Huang
aa49d8e8b2 tty: serial: imx: Add return value check for platform_get_irq()
RX irq is required, so add return value check for platform_get_irq().

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1589180996-618-1-git-send-email-Anson.Huang@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15 12:25:15 +02:00
George Hilliard
5a08a4877a tty: imx serial: Implement support for reversing TX and RX polarity
The peripheral has support for inverting its input and/or output
signals.  This is useful if the hardware flips polarity of the
peripheral's signal, such as swapped +/- pins on an RS-422 transceiver,
or an inverting level shifter.  Add support for these control registers
via the device tree binding.

As part of this change, make the writes of the various registers more
uniform by moving the UCR3 block up near the other registers' blocks,
since the INVT bit must be set before enabling the peripheral.

Signed-off-by: George Hilliard <ghilliard@kopismobile.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20200226222319.18383-3-ghilliard@kopismobile.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-06 13:26:26 +01:00
Fugang Duan
f767078318 tty: serial: imx: setup the correct sg entry for tx dma
There has oops as below happen on i.MX8MP EVK platform that has
6G bytes DDR memory.

when (xmit->tail < xmit->head) && (xmit->head == 0),
it setups one sg entry with sg->length is zero:
	sg_set_buf(sgl + 1, xmit->buf, xmit->head);

if xmit->buf is allocated from >4G address space, and SDMA only
support <4G address space, then dma_map_sg() will call swiotlb_map()
to do bounce buffer copying and mapping.

But swiotlb_map() don't allow sg entry's length is zero, otherwise
report BUG_ON().

So the patch is to correct the tx DMA scatter list.

Oops:
[  287.675715] kernel BUG at kernel/dma/swiotlb.c:497!
[  287.680592] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
[  287.686075] Modules linked in:
[  287.689133] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.3-00016-g3fdc4e0-dirty #10
[  287.696872] Hardware name: FSL i.MX8MP EVK (DT)
[  287.701402] pstate: 80000085 (Nzcv daIf -PAN -UAO)
[  287.706199] pc : swiotlb_tbl_map_single+0x1fc/0x310
[  287.711076] lr : swiotlb_map+0x60/0x148
[  287.714909] sp : ffff800010003c00
[  287.718221] x29: ffff800010003c00 x28: 0000000000000000
[  287.723533] x27: 0000000000000040 x26: ffff800011ae0000
[  287.728844] x25: ffff800011ae09f8 x24: 0000000000000000
[  287.734155] x23: 00000001b7af9000 x22: 0000000000000000
[  287.739465] x21: ffff000176409c10 x20: 00000000001f7ffe
[  287.744776] x19: ffff000176409c10 x18: 000000000000002e
[  287.750087] x17: 0000000000000000 x16: 0000000000000000
[  287.755397] x15: 0000000000000000 x14: 0000000000000000
[  287.760707] x13: ffff00017f334000 x12: 0000000000000001
[  287.766018] x11: 00000000001fffff x10: 0000000000000000
[  287.771328] x9 : 0000000000000003 x8 : 0000000000000000
[  287.776638] x7 : 0000000000000000 x6 : 0000000000000000
[  287.781949] x5 : 0000000000200000 x4 : 0000000000000000
[  287.787259] x3 : 0000000000000001 x2 : 00000001b7af9000
[  287.792570] x1 : 00000000fbfff000 x0 : 0000000000000000
[  287.797881] Call trace:
[  287.800328]  swiotlb_tbl_map_single+0x1fc/0x310
[  287.804859]  swiotlb_map+0x60/0x148
[  287.808347]  dma_direct_map_page+0xf0/0x130
[  287.812530]  dma_direct_map_sg+0x78/0xe0
[  287.816453]  imx_uart_dma_tx+0x134/0x2f8
[  287.820374]  imx_uart_dma_tx_callback+0xd8/0x168
[  287.824992]  vchan_complete+0x194/0x200
[  287.828828]  tasklet_action_common.isra.0+0x154/0x1a0
[  287.833879]  tasklet_action+0x24/0x30
[  287.837540]  __do_softirq+0x120/0x23c
[  287.841202]  irq_exit+0xb8/0xd8
[  287.844343]  __handle_domain_irq+0x64/0xb8
[  287.848438]  gic_handle_irq+0x5c/0x148
[  287.852185]  el1_irq+0xb8/0x180
[  287.855327]  cpuidle_enter_state+0x84/0x360
[  287.859508]  cpuidle_enter+0x34/0x48
[  287.863083]  call_cpuidle+0x18/0x38
[  287.866571]  do_idle+0x1e0/0x280
[  287.869798]  cpu_startup_entry+0x20/0x40
[  287.873721]  rest_init+0xd4/0xe0
[  287.876949]  arch_call_rest_init+0xc/0x14
[  287.880958]  start_kernel+0x420/0x44c
[  287.884622] Code: 9124c021 9417aff8 a94363f7 17ffffd5 (d4210000)
[  287.890718] ---[ end trace 5bc44c4ab6b009ce ]---
[  287.895334] Kernel panic - not syncing: Fatal exception in interrupt
[  287.901686] SMP: stopping secondary CPUs
[  288.905607] SMP: failed to stop secondary CPUs 0-1
[  288.910395] Kernel Offset: disabled
[  288.913882] CPU features: 0x0002,2000200c
[  288.917888] Memory Limit: none
[  288.920944] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

Reported-by: Eagle Zhou <eagle.zhou@nxp.com>
Tested-by: Eagle Zhou <eagle.zhou@nxp.com>
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Cc: stable <stable@vger.kernel.org>
Fixes: 7942f8577f ("serial: imx: TX DMA: clean up sg initialization")
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/1581401761-6378-1-git-send-email-fugang.duan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-12 11:55:21 -08:00
Uwe Kleine-König
101aa46bd2 serial: imx: fix a race condition in receive path
The main irq handler function starts by first masking disabled
interrupts in the status register values to ensure to only handle
enabled interrupts. This is important as when the RX path in the
hardware is disabled reading the RX fifo results in an external abort.

This checking must be done under the port lock, otherwise the following
can happen:

     CPU1                            | CPU2
                                     |
     irq triggers as there are chars |
     in the RX fifo                  |
				     | grab port lock
     imx_uart_int finds RRDY enabled |
     and calls imx_uart_rxint which  |
     has to wait for port lock       |
                                     | disable RX (e.g. because we're
                                     | using RS485 with !RX_DURING_TX)
                                     |
                                     | release port lock
     read from RX fifo with RX       |
     disabled => exception           |

So take the port lock only once in imx_uart_int() instead of in the
functions called from there.

Reported-by: Andre Renaud <arenaud@designa-electronics.com>
Cc: stable@vger.kernel.org
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20200121071702.20150-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-22 10:22:31 +01:00
Dmitry Safonov
aa3479d2e6 tty/serial: Migrate imx to use has_sysrq
The SUPPORT_SYSRQ ifdeffery is not nice as:
- May create misunderstanding about sizeof(struct uart_port) between
  different objects
- Prevents moving functions from serial_core.h
- Reduces readability (well, it's ifdeffery - it's hard to follow)

In order to remove SUPPORT_SYSRQ, has_sysrq variable has been added.
Initialise it in driver's probe and remove ifdeffery.

Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20191213000657.931618-20-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-18 15:04:49 +01:00
Peng Fan
596fd8dffb tty: serial: imx: use the sg count from dma_map_sg
The dmaengine_prep_slave_sg needs to use sg count returned
by dma_map_sg, not use sport->dma_tx_nents, because the return
value of dma_map_sg is not always same with "nents".

Fixes: b4cdc8f61b ("serial: imx: add DMA support for imx6q")
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/1573108875-26530-1-git-send-email-peng.fan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-13 19:01:15 +08:00
Greg Kroah-Hartman
7ca932e441 Merge 5.4-rc3 into tty-next
We need the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-14 07:32:24 +02:00
Anson Huang
31a8d8fa84 tty: serial: imx: Use platform_get_irq_optional() for optional IRQs
All i.MX SoCs except i.MX1 have ONLY one necessary IRQ, use
platform_get_irq_optional() to get second/third IRQ which are
optional to avoid below error message during probe:

[    0.726219] imx-uart 30860000.serial: IRQ index 1 not found
[    0.731329] imx-uart 30860000.serial: IRQ index 2 not found

Fixes: 7723f4c5ec ("driver core: platform: Add an error message to platform_get_irq*()")
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1570614559-11900-1-git-send-email-Anson.Huang@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-10 13:12:28 +02:00
Philipp Puschmann
76c38d30fe serial: imx: adapt rx buffer and dma periods
Using only 4 DMA periods for UART RX is very few if we have a high
frequency of small transfers - like in our case using Bluetooth with
many small packets via UART - causing many dma transfers but in each
only filling a fraction of a single buffer. Such a case may lead to
the situation that DMA RX transfer is triggered but no free buffer is
available. When this happens dma channel ist stopped - with the patch
"dmaengine: imx-sdma: fix dma freezes" temporarily only - with the
possible consequences that:
with disabled hw flow control:
  If enough data is incoming on UART port the RX FIFO runs over and
  characters will be lost. What then happens depends on upper layer.

with enabled hw flow control:
  If enough data is incoming on UART port the RX FIFO reaches a level
  where CTS is deasserted and remote device sending the data stops.
  If it fails to stop timely the i.MX' RX FIFO may run over and data
  get lost. Otherwise it's internal TX buffer may getting filled to
  a point where it runs over and data is again lost. It depends on
  the remote device how this case is handled and if it is recoverable.

Obviously we want to avoid having no free buffers available. So we
decrease the size of the buffers and increase their number and the
total buffer size.

Signed-off-by: Philipp Puschmann <philipp.puschmann@emlix.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Link: https://lore.kernel.org/r/20190923135916.1212-1-philipp.puschmann@emlix.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-04 14:46:13 +02:00
Sergey Organov
c514a6f848 serial: imx: use Tx ready rather than Tx empty irq
This should help to avoid unnecessary gaps in transmission while
adding little overhead due to low default Tx threshold level (2
bytes).

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-6-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-04 12:43:55 +02:00
Sergey Organov
d47bcb4a6c serial: imx: fix data breakage on termios change
imx_set_termios(): avoid writing baud rate divider registers when the
values to be written are the same as current. Any writing seems to
restart transmission/receiving logic in the hardware, that leads to
data breakage even when rate doesn't in fact change. E.g., user
switches RTS/CTS handshake and suddenly gets broken bytes.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-5-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-04 12:43:55 +02:00
Sergey Organov
85f30fbf32 serial: imx: do not disable individual irqs during termios change
imx_set_termios(): disabling individual interrupt requests in UART for
duration of the routine is pointless. Get rid of it.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-4-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-04 12:43:55 +02:00
Sergey Organov
88c38044c1 serial: imx: do not stop Rx/Tx on termios change
imx_set_termios(): stopping receiver and transmitter does harm when
something that doesn't touch transmission format/rate changes, such as
RTS/CTS handshake.

OTOH, it does no good on baud rate or format change, as
synchronization on upper-level protocols is still required to do it
right.

Therefore, just stop doing it.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-3-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-04 12:43:55 +02:00
Sergey Organov
2eda5345e4 serial: imx: get rid of unbounded busy-waiting loop
imx_set_termios(): remove busy-waiting "drain Tx FIFO" loop. Worse
yet, it was potentially unbounded wait due to RTS/CTS (hardware)
handshake.

Let user space ensure draining is done before termios change, if
draining is needed in the first place.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1567017475-11919-2-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-04 12:43:55 +02:00
Sergey Organov
b777b5de6a serial: imx: get rid of imx_uart_rts_auto()
Called in only one place, for RS232, it only obscures things, as it
doesn't go well with 2 similar named functions,
imx_uart_rts_inactive() and imx_uart_rts_active(), that both are
RS485-specific.

Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1564167161-3972-4-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-04 12:43:46 +02:00
Sergey Organov
197540dc83 serial: imx: set_mctrl(): correctly restore autoRTS state
imx_uart_set_mctrl() happened to set UCR2_CTSC bit whenever TIOCM_RTS
was set, no matter if RTS/CTS handshake is enabled or not. Now fixed by
turning handshake on only when CRTSCTS bit for the port is set.

Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1564167161-3972-3-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-04 12:43:46 +02:00
Sergey Organov
a25aee902e serial: imx: set_termios(): do not enable autoRTS if RTS is unset
Don't let receiver hardware automatically control RTS output if it
was requested to be inactive.

To ensure this, set_termios() shouldn't set UCR2_CTSC bit if UCR2_CTS
(=TIOCM_RTS) is cleared. Added corresponding check in imx_uart_rts_auto()
to fix this.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1564167161-3972-2-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-04 12:43:46 +02:00
Sergey Organov
011bd05d1f serial: imx: set_termios(): preserve RTS state
imx_set_termios() cleared RTS on every call, now fixed.

Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1561558293-7683-5-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-03 19:35:42 +02:00
Sergey Organov
ddf89e7503 serial: imx: set_termios(): clarify RTS/CTS bits calculation
Avoid repeating the same code for rs485 twice.

Make it obvious we clear CRTSCTS bit in termios->c_cflag whenever
sport->have_rtscts is false.

Make it obvious we clear UCR2_IRTS whenever CRTSCTS is set.

Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Link: https://lore.kernel.org/r/1561558293-7683-4-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-03 19:35:41 +02:00
Sergey Organov
41ffa48ea7 serial: imx: set_termios(): factor-out 'ucr2' initial value
Set common bits in a separate statement to make initialization
explicit and not repeat the common part.

Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Reviewed-by: Uwe Kleine-Knig <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/1561558293-7683-3-git-send-email-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-03 19:35:41 +02:00
Sergey Organov
4e828c3e09 serial: imx: fix locking in set_termios()
imx_uart_set_termios() called imx_uart_rts_active(), or
imx_uart_rts_inactive() before taking port->port.lock.

As a consequence, sport->port.mctrl that these functions modify
could have been changed without holding port->port.lock.

Moved locking of port->port.lock above the calls to fix the issue.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-18 09:30:44 +02:00
Fabio Estevam
f5a9e5f7dd serial: imx: Use dev_info() instead of pr_info()
dev_info() is more appropriate for printing messages inside drivers, so
switch to dev_info().

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-10 19:12:09 +02:00
Sascha Hauer
8178eeb3e8 serial: imx: remove log spamming error message
Each time the DMA engine signals a transaction error the driver prints
a message at error level. Getting transaction errors is pretty much
expected on baudrate mismatches and the correspoding error counters
are increased in this case properly. Remove the error message which
is possibly repeated at a very high rate which can lock up the whole
system.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 12:18:17 +02:00
Stefan Agner
63fd4b94b9 serial: imx: fix error handling in console_setup
The ipg clock only needs to be unprepared in case preparing
per clock fails. The ipg clock has already disabled at the point.

Fixes: 1cf93e0d54 ("serial: imx: remove the uart_console() check")
Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-27 09:56:20 +01:00
Greg Kroah-Hartman
669c5d8d5f Merge 4.19-rc6 into tty-next
We want the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-30 08:11:09 -07:00
Uwe Kleine-König
7e620984b6 serial: imx: restore handshaking irq for imx1
Back in 2015 when irda was dropped from the driver imx1 was broken. This
change reintroduces the support for the third interrupt of the UART.

Fixes: afe9cbb1a6 ("serial: imx: drop support for IRDA")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-20 14:51:31 +02:00
Anson Huang
fcfed1be53 tty: serial: imx: add pinctrl sleep/default mode switch for suspend
On some i.MX SoCs' low power mode, such as i.MX7D's LPSR(low power
state retention), UART iomux settings will be lost, need to add
pinctrl sleep/default mode switch during suspend/resume to make
sure UART iomux settings are correct after resume.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-18 16:07:24 +02:00
Anson Huang
07b5e16e98 tty: serial: imx: add lock for registers save/restore
In noirq suspend/resume stage with no_console_suspend enabled,
imx_uart_console_write() may be called to print out log_buf
message by printk(), so there will be race condition between
imx_uart_console_write() and imx_uart_save/restore_context(),
need to add lock to protect the registers save/restore operations.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-18 16:07:24 +02:00