-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2
iQIbBAABAgAGBQJbFnd0AAoJEFKgDEdIgJTyuWgP+O/+kRbXR5WTphJ8e9+CqHp4
LF6AJXTuiA0fPJ5TcTNtZ84AVvmoNcTXnaM3Ou8HfR2qER8Gqu4WbdcfqhU2/KUq
L4x4YlW+DZPOhy7chFx/yTgdSWc8vBwSG80DLSQhjnOJBY4SwBaVSSCYi/CSiAvr
I18zt03mSXUe9RADrT3W0rbryIbyICvZjMbKkUlSm7ZTQv482FaU2Jezp86qDYLB
FWc7QOLKzXRjFTg5IQ91mTtqnM2gnHwqOzGFR+jILn8BQwVe5dYp42sCSne34kBD
pHz5GosIIYRH3Eik7pNzOhN4nsncLfPwwQQx/YH1KmKteNPTPJZO01pEwMaurc3w
LaoTD7LNDyZCkzxJF/kKOiW4ys1cMf5jyoiV9Sou7PIVPcxuR1ToMXQvHSplZPG1
UyDwW41XVmluYdC2O4ybRQWMu3nmrQKCjjGkCmizK3xMWNs4u/5Y4kS3mi7Zwk3y
X1wlm2BW7RPzVl7WWlNergR2UHNq2zgToOWzFfSqXtMukYbmei+mXYIIe6nKa2GH
ji/d/Sr/RIAgUs46sBzRBLK9ZCqybPxSvnfNZx8WodLU1dLYT3yY1vGZbGPEMB2w
puS7ctPT9dfnBxi/MOegXlTyKTOJkCB3o/bsWkIdSvRI45qbYE1aQN8IMmDQ20sv
X8A3LnDQZvUfKEULrU0=
=hB2y
-----END PGP SIGNATURE-----
Merge tag 'printk-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek:
- Help userspace log daemons to catch up with a flood of messages. They
will get woken after each message even if the console is far behind
and handled by another process.
- Flush printk safe buffers safely even when panic() happens in the
normal context.
- Fix possible va_list reuse when race happened in printk_safe().
- Remove %pCr printf format to prevent sleeping in the atomic context.
- Misc vsprintf code cleanup.
* tag 'printk-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
printk: drop in_nmi check from printk_safe_flush_on_panic()
lib/vsprintf: Remove atomic-unsafe support for %pCr
serial: sh-sci: Stop using printk format %pCr
thermal: bcm2835: Stop using printk format %pCr
clk: renesas: cpg-mssr: Stop using printk format %pCr
printk: fix possible reuse of va_list variable
printk: wake up klogd in vprintk_emit
vsprintf: Tweak pF/pf comment
lib/vsprintf: Mark expected switch fall-through
lib/vsprintf: Replace space with '_' before crng is ready
lib/vsprintf: Deduplicate pointer_string()
lib/vsprintf: Move pointer_string() upper
lib/vsprintf: Make flag_spec global
lib/vsprintf: Make strspec global
lib/vsprintf: Make dec_spec global
lib/test_printf: Mark big constant with UL
Here is the big tty/serial driver update for 4.18-rc1.
There's nothing major here, just lots of serial driver updates. Full
details are in the shortlog, nothing anything specific to call out here.
All have been in linux-next for a while with no reported issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-----BEGIN PGP SIGNATURE-----
iG0EABECAC0WIQT0tgzFv3jCIUoxPcsxR9QN2y37KQUCWxbZzQ8cZ3JlZ0Brcm9h
aC5jb20ACgkQMUfUDdst+ym2pQCggrWJsOeXLXgzhVDH6/qMFP9R/hEAoLTvmOWQ
BlPIlvRDm/ud33VogJ8t
=XS8u
-----END PGP SIGNATURE-----
Merge tag 'tty-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial updates from Greg KH:
"Here is the big tty/serial driver update for 4.18-rc1.
There's nothing major here, just lots of serial driver updates. Full
details are in the shortlog, nothing anything specific to call out
here.
All have been in linux-next for a while with no reported issues"
* tag 'tty-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (55 commits)
vt: Perform safe console erase only once
serial: imx: disable UCR4_OREN on shutdown
serial: imx: drop CTS/RTS handling from shutdown
tty: fix typo in ASYNCB_FOURPORT comment
serial: samsung: check DMA engine capabilities before using DMA mode
tty: Fix data race in tty_insert_flip_string_fixed_flag
tty: serial: msm_geni_serial: Fix TX infinite loop
serial: 8250_dw: Fix runtime PM handling
serial: 8250: omap: Fix idling of clocks for unused uarts
tty: serial: drop ATH79 specific SoC symbols
serial: 8250: Add missing rxtrig_bytes on Altera 16550 UART
serial/aspeed-vuart: fix a couple mod_timer() calls
serial: sh-sci: Use spin_{try}lock_irqsave instead of open coding version
serial: 8250_of: Add IO space support
tty/serial: atmel: use port->name as name in request_irq()
serial: imx: dma_unmap_sg buffers on shutdown
serial: imx: cleanup imx_uart_disable_dma()
tty: serial: qcom_geni_serial: Add early console support
tty: serial: qcom_geni_serial: Return IRQ_NONE for spurious interrupts
tty: serial: qcom_geni_serial: Use iowrite32_rep to write to FIFO
...
Printk format "%pCr" will be removed soon, as clk_get_rate() must not be
called in atomic context.
Replace it by open-coding the operation. This is safe here, as the code
runs in task context.
Link: http://lkml.kernel.org/r/1527845302-12159-4-git-send-email-geert+renesas@glider.be
To: Jia-Ju Bai <baijiaju1990@gmail.com>
To: Jonathan Corbet <corbet@lwn.net>
To: Michael Turquette <mturquette@baylibre.com>
To: Stephen Boyd <sboyd@kernel.org>
To: Zhang Rui <rui.zhang@intel.com>
To: Eduardo Valentin <edubezval@gmail.com>
To: Eric Anholt <eric@anholt.net>
To: Stefan Wahren <stefan.wahren@i2se.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-clk@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: stable@vger.kernel.org # 4.5+
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Petr Mladek <pmladek@suse.com>
UCR4_OREN is (depending on the configuration) enabled in startup,
but is never disabled. Fix this by disabling it in shutdown.
Reported-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
According to Documentation/serial/driver the shutdown function should
not disable RTS, so drop it.
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
DMA engine driver might not always provide all the features needed by
serial driver to properly operate in DMA mode, so check that before
selecting DMA mode.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Just set up the show callback in the tty_operations, and use
proc_create_single_data to create the file without additional
boilerplace code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
The GENI serial driver handled transmit by leaving stuff in the
common circular buffer until it had completely caught up to the head,
then clearing it out all at once. This is a suboptimal way to do
transmit, as it leaves data in the circular buffer that could be
freed. Moreover, the logic implementing it is wrong, and it is easy to
get into a situation where the UART infinitely writes out the same buffer.
I could reproduce infinite serial output of the same buffer by running
dmesg, then hitting Ctrl-C. I believe what happened is xmit_size was
something large, marching towards a larger value. Then the generic OS
code flushed out the buffer and replaced it with two characters. Now the
xmit_size is a large value marching towards a small value, which it wasn't
expecting. The driver subtracts xmit_size (very large) from
uart_circ_chars_pending (2), underflows, and repeats ad nauseum. The
locking isn't wrong here, as the locks are held whenever the buffer is
manipulated, it's just that the driver wasn't expecting the buffer to be
flushed out from underneath it in between transmits.
This change reworks transmit to grab what it can from the circular buffer,
and then update ->tail, both fixing the underflow and freeing up space
for a smoother circular experience.
Signed-off-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When using kgdb, you get an abort when accessing the UART registers.
This is because the driver has already entered runtime PM and so turned
off the bus clock needed to access the registers.
To fix this, set the capability indicating Runtime PM is active while idle.
Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
I noticed that unused UARTs won't necessarily idle properly always
unless at least one byte tx transfer is done first.
After some debugging I narrowed down the problem to the scr register
dma configuration bits that need to be set before softreset for the
clocks to idle. Unless we do this, the module clkctrl idlest bits
may be set to 1 instead of 3 meaning the clock will never idle and
is blocking deeper idle states for the whole domain.
This might be related to the configuration done by the bootloader
or kexec booting where certain configurations cause the 8250 or
the clkctrl clock to jam in a way where setting of the scr bits
and reset is needed to clear it. I've tried diffing the 8250
registers for the various modes, but did not see anything specific.
So far I've only seen this on omap4 but I'm suspecting this might
also happen on the other clkctrl using SoCs considering they
already have a quirk enabled for UART_ERRATA_CLOCK_DISABLE.
Let's fix the issue by configuring scr before reset for basic dma
even if we don't use it. The scr register will be reset when we do
softreset few lines after, and we restore scr on resume. We should
do this for all the SoCs with UART_ERRATA_CLOCK_DISABLE quirk flag
set since the ones with UART_ERRATA_CLOCK_DISABLE are all based
using clkctrl similar to omap4.
Looks like both OMAP_UART_SCR_DMAMODE_1 | OMAP_UART_SCR_DMAMODE_CTL
bits are needed for the clkctrl to idle after a softreset.
And we need to add omap4 to also use the UART_ERRATA_CLOCK_DISABLE
for the related workaround to be enabled. This same compatible
value will also be used for omap5.
Fixes: cdb929e445 ("serial: 8250_omap: workaround errata around idling UART after using DMA")
Cc: Keerthy <j-keerthy@ti.com>
Cc: Matthijs van Duin <matthijsvanduin@gmail.com>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
QCA MIPS support is being converted to pure OF. As part of this we are
dropping the SOC_AR* symbols. Additionally the SERIAL_AR933X style tty
is also found on a few SoCs newer that the AR933x.
This patch changes the dependency to ATH79, thus fixing the 2 issues
described above.
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Altera 16550 UART core supports FCR Rx Trigger Level setting,
but the port definition in the driver is missing the rxtrig_bytes
array specifying the trigger levels. Add the array to make the Rx
Trigger Level setting available on this type of 16550 UART.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Thor Thayer <tthayer@opensource.altera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The "unthrottle_timeout" is HZ/10 but mod_timer() takes a the actual
jiffie where you want it to timeout, not an offset.
Fixes: 5909c0bf9c ("serial/aspeed-vuart: Implement quick throttle mechanism")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
Currently the 8250_of driver only supports MEM IO type
accesses.
Some development boards (Huawei D03, specifically) require
IO space access for 8250-compatible OF driver support, so
add it.
The modification is quite simple: just set the port iotype
and associated flags depending on the device address
resource type.
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
I was puzzled while looking at /proc/interrupts and random things showed
up between reboots. This occurred more often but I realised it later. The
"correct" output should be:
|38: 11861 atmel-aic5 2 Level ttyS0
but I saw sometimes
|38: 6426 atmel-aic5 2 Level tty1
and accounted it wrongly as correct. This is use after free and the
former example randomly got the "old" pointer which pointed to the same
content. With SLAB_FREELIST_RANDOM and HARDENED I even got
|38: 7067 atmel-aic5 2 Level E=Started User Manager for UID 0
or other nonsense.
As it turns out the tty, pointer that is accessed in atmel_startup(), is
freed() before atmel_shutdown(). It seems to happen quite often that the
tty for ttyS0 is allocated and freed while ->shutdown is not invoked. I
don't do anything special - just a systemd boot :)
Use dev_name(&pdev->dev) as the IRQ name for request_irq(). This exists
as long as the driver is loaded so no use-after-free here.
Cc: stable@vger.kernel.org
Fixes: 761ed4a945 ("tty: serial_core: convert uart_close to use tty_port_close")
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This properly unmaps DMA SG on device shutdown.
Reported-by: Nandor Han <nandor.han@ge.com>
Suggested-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove unrelated CTSC/CTS disabling from imx_uart_disable_dma() and
move it to imx_uart_shutdown(), which is the only user of the DMA
disabling function. This should not change the driver's behaviour,
but improves readability. After this change imx_uart_disable_dma()
does the reverse thing of imx_uart_enable_dma().
Suggested-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently the driver returns IRQ_HANDLED when spurious interrupts happen.
This is misleading. Fix the behavior by returning IRQ_NONE for spurious
interrupts.
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use iowrite32_rep to write to the hardware FIFO so that the code does
not have to worry about the system endianness.
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While initiating TX, only the register reads need to be ordered. The
register write order either is achieved due to data dependency or is
not required.
Use readl to achieve the read order and remove the unnecessary barrier.
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Perform static initialization of console_port since its initial state has
no run-time dependencies.
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use min3 helper to calculate the minimum value of 3 variables.
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Document reason for newline character counting in console_write
* Document reason for disabling IRQ in the system resume operation
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The best granularity of residue that DMA engine can report is in the BURST
units, so the serial driver must use MAXBURST = 1 and DMA_SLAVE_BUSWIDTH_1_BYTE
if it relies on exact number of bytes transferred by DMA engine.
Fixes: 62c37eedb7 ("serial: samsung: add dma reqest/release functions")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As stated under "20) Conditional Compilation" in coding-style.rst. We
shall rather use __maybe_unused than preprocessor macros in such cases.
Signed-off-by: Pascal Huerst <pascal.huerst@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There is no reason to initialize uartclk to BASE_BAUD * 16 for DT based
systems.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Tested-by: Matt Redfearn <matt.redfearn@mips.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 9b96fbacda ("serial: PL011: clear pending interrupts")
clears the RX and receive timeout interrupts on pl011 startup, to
avoid a screaming-interrupt scenario that can occur when the
firmware or bootloader leaves these interrupts asserted.
This has been noted as an issue when running Linux on qemu [1].
Unfortunately, the above fix seems to lead to potential
misbehaviour if the RX FIFO interrupt is asserted _non_ spuriously
on driver startup, if the RX FIFO is also already full to the
trigger level.
Clearing the RX FIFO interrupt does not change the FIFO fill level.
In this scenario, because the interrupt is now clear and because
the FIFO is already full to the trigger level, no new assertion of
the RX FIFO interrupt can occur unless the FIFO is drained back
below the trigger level. This never occurs because the pl011
driver is waiting for an RX FIFO interrupt to tell it that there is
something to read, and does not read the FIFO at all until that
interrupt occurs.
Thus, simply clearing "spurious" interrupts on startup may be
misguided, since there is no way to be sure that the interrupts are
truly spurious, and things can go wrong if they are not.
This patch instead clears the interrupt condition by draining the
RX FIFO during UART startup, after clearing any potentially
spurious interrupt. This should ensure that an interrupt will
definitely be asserted if the RX FIFO subsequently becomes
sufficiently full.
The drain is done at the point of enabling interrupts only. This
means that it will occur any time the UART is newly opened through
the tty layer. It will not apply to polled-mode use of the UART by
kgdboc: since that scenario cannot use interrupts by design, this
should not matter. kgdboc will interact badly with "normal" use of
the UART in any case: this patch makes no attempt to paper over
such issues.
This patch does not attempt to address the case where the RX FIFO
fills faster than it can be drained: that is a pathological
hardware design problem that is beyond the scope of the driver to
work around. As a failsafe, the number of poll iterations for
draining the FIFO is limited to twice the FIFO size. This will
ensure that the kernel at least boots even if it is impossible to
drain the FIFO for some reason.
[1] [Qemu-devel] [Qemu-arm] [PATCH] pl011: do not put into fifo
before enabled the interruption
https://lists.gnu.org/archive/html/qemu-devel/2018-01/msg06446.html
Reported-by: Wei Xu <xuwei5@hisilicon.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Peter Maydell <peter.maydell@linaro.org>
Fixes: 9b96fbacda ("serial: PL011: clear pending interrupts")
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Cc: stable <stable@vger.kernel.org>
Tested-by: Wei Xu <xuwei5@hisilicon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
c&p this function to probe as preparation for removing
cdns_uart_port[] static array.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Driver console functions are using pointer to static array with fixed
size. There can be only one serial console at the time which is found
by register_console(). register_console() is filling cons->index to
port->line value.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
register_console() is called from
uart_add_one_port()->uart_configure_port()
that's why register_console() is called twice.
This patch remove console_initcall to call register_console() only from
one location.
Also based on my tests cdns_uart_console_setup() is not called
from the first register_console() call.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the clock is enabled, check if there is an error. Otherwise
clk_get_rate() can be called without enabled clock.
Found by Linux Driver Verification project (linuxtesting.org).
Fixes: 0814e8d5da ("sc16is7xx: enable the clock")
Signed-off-by: Stefan Potyra <Stefan.Potyra@elektrobit.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
device->baud is always non zero value because it is checked already in
early_serial8250_setup() before init_port is called.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Baudrate calculation depends on requested baudrate and uart clock.
This patch is checking that uartclk is also passed.
The same logic is used 8250_early.c/init_port function.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The platform_get_irq can return error. Assigning the return value to an
unsigned variable and checking it for negative value will always return
false.
Use an intermediate signed variable to get IRQ information, check for any
error and then assign it to 'irq' variable inside uart_port structure.
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Although we populate the ->throttle and ->unthrottle UART operations,
these may not be called until the ldisc has had a chance to schedule and
check buffer space. This means that we may overflow the flip buffers
without ever hitting the ldisc's throttle threshold.
This change implements an interrupt-based throttle, where we check for
space in the flip buffers before reading characters from the UART's
FIFO. If there's no space available, we disable the RX interrupt and
schedule a timer to check for space later.
For this, we need an unlocked version of the set_throttle function to be
able to change throttle state from the irq_handler, which already holds
port->lock.
This prevents a case where we drop characters under heavy RX load.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Tested-by: Eddie James <eajames@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The aspeed VUART runs at LPC bus frequency, rather than being restricted
to a typical UART baud rate. This means that the VUART can receive a lot
of data, which can overrun tty flip buffers, and/or cause a large amount
of interrupt traffic.
This change implements the uart_port->throttle & unthrottle callbacks,
implemented by disabling the receiver line status & received data
available IRQs.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Tested-by: Eddie James <eajames@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, we export serial8250_rx_chars, which does a whole bunch of
reads from the 8250 data register, without any form of flow control
between reads.
An upcoming change to the aspeed vuart driver implements more
fine-grained flow control in the interrupt handler, requiring
character-at-a-time control over the rx path.
This change exports serial8250_read_char to allow this.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Tested-by: Eddie James <eajames@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This change adds a flag to indicate that a UART is has an external means
of synchronising its FIFO, without needing CTSRTS or XON/XOFF.
This allows us to use the throttle/unthrottle callbacks, without having
to claim other methods of flow control.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Tested-by: Eddie James <eajames@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove dependencies on HAS_DMA where a Kconfig symbol depends on another
symbol that implies HAS_DMA, and, optionally, on "|| COMPILE_TEST".
In most cases this other symbol is an architecture or platform specific
symbol, or PCI.
Generic symbols and drivers without platform dependencies keep their
dependencies on HAS_DMA, to prevent compiling subsystems or drivers that
cannot work anyway.
This simplifies the dependencies, and allows to improve compile-testing.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On DT based platforms when current-speed property is present baudrate
is setup. Also port->uartclk is initialized to bogus BASE_BAUD * 16
value. Drivers like uartps/ns16550 contain logic when baudrate and
uartclk is used for baudrate calculation.
The patch is reading optional clock-frequency property to replace bogus
BASE_BAUD * 16 calculation to have proper baudrate calculation.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On some systems IRQ lines between multiple UARTs might be shared. If so, the
irqflags have to be configured accordingly. The reason is: The 8250 port startup
code performs IRQ tests *before* the IRQ handler for that particular port is
registered. This is performed in serial8250_do_startup(). This function checks
whether IRQF_SHARED is configured and only then disables the IRQ line while
testing.
This test is performed upon each open() of the UART device. Imagine two UARTs
share the same IRQ line: On is already opened and the IRQ is active. When the
second UART is opened, the IRQ line has to be disabled while performing IRQ
tests. Otherwise an IRQ might handler might be invoked, but the the IRQ itself
cannot be handled, because the corresponding handler isn't registered,
yet. That's because the 8250 code uses a chain-handler and invokes the
corresponding port's IRQ handling rountines himself.
Unfortunately this IRQF_SHARED flag isn't configured for UARTs probed via device
tree even if the IRQs are shared. This way, the actual and shared IRQ line isn't
disabled while performing tests and the kernel correctly detects a spurious
IRQ. So, adding this flag to the DT probe solves the issue.
Note: The UPF_SHARE_IRQ flag is configured unconditionally. Therefore, the
IRQF_SHARED flag can be set unconditionally as well.
Example stacktrace by performing echo 1 > /dev/ttyS2 on a non-patched system:
|irq 85: nobody cared (try booting with the "irqpoll" option)
| [...]
|handlers:
|[<ffff0000080fc628>] irq_default_primary_handler threaded [<ffff00000855fbb8>] serial8250_interrupt
|Disabling IRQ #85
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Enable/Clear module level UART wakeup in UART_OMAP_WER register based on
return value of device_may_wakeup() in .suspend(). This allows
userspace to use sysfs to control the ability of UART to wakeup the
system from deep sleep state. Register is restored back in .startup()
call that happens as part of resume sequence.
With this patch, userspace can control UART wakeup capability via sysfs:
To enable wakeup capability:
echo enabled > /sys/class/tty/ttyXX/device/power/wakeup
For disabling wakeup capability:
echo disabled > /sys/class/tty/ttyXX/device/power/wakeup
Note that the UART wakeup events configured in the 8250 hardware only
work for idle modes that do not cut off power for the UART. For deeper
idle states, dedicated padconf wakeirqs must be used. Or in some cases
the UART RX pin can be remuxed to GPIO input if the GPIO block stays
powered.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Kees Cook
Linus Torvalds
Geert Uytterhoeven
Sebastian Reichel
Marek Szyprowski
Christoph Hellwig
Evan Green
Phil Edworthy
Tony Lindgren
John Crispin
Marek Vasut
Dan Carpenter
Daniel Wagner
John Garry
Sebastian Andrzej Siewior
Karthikeyan Ramasubramanian
Pascal Huerst
Michal Simek
Dave Martin
Greg Kroah-Hartman
Stefan Potyra
Jeremy Kerr
Geert Uytterhoeven
Kurt Kanzenbach
Vignesh R