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commit cce7fc8b29961b64fadb1ce398dc5ff32a79643b upstream.
In case the leaf driver wants to use IRQ polling (irq = 0) and
IIR register shows that an interrupt happened in the 8250 hardware
the IRQ data can be NULL. In such a case we need to skip the wake
event as we came to this path from the timer interrupt and quite
likely system is already awake.
Without this fix we have got an Oops:
serial8250: ttyS0 at I/O 0x3f8 (irq = 0, base_baud = 115200) is a 16550A
...
BUG: kernel NULL pointer dereference, address: 0000000000000010
RIP: 0010:serial8250_handle_irq+0x7c/0x240
Call Trace:
? serial8250_handle_irq+0x7c/0x240
? __pfx_serial8250_timeout+0x10/0x10
Fixes: 0ba9e3a13c6a ("serial: 8250: Add missing wakeup event reporting")
Cc: stable <stable@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20230831222555.614426-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit dfe2aeb226fd5e19b0ee795f4f6ed8bc494c1534 ]
Unloading a hardware specific 8250 driver can produce error "Unable to
handle kernel paging request at virtual address" about ten seconds after
unloading the driver. This happens on uart_hangup() calling
uart_change_pm().
Turns out commit 04e82793f068 ("serial: 8250: Reinit port->pm on port
specific driver unbind") was only a partial fix. If the hardware specific
driver has initialized port->pm function, we need to clear port->pm too.
Just reinitializing port->ops does not do this. Otherwise serial8250_pm()
will call port->pm() instead of serial8250_do_pm().
Fixes: 04e82793f068 ("serial: 8250: Reinit port->pm on port specific driver unbind")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20230804131553.52927-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit a82d62f708545d22859584e0e0620da8e3759bbc upstream.
This reverts commit eb26dfe8aa7eeb5a5aa0b7574550125f8aa4c3b3.
Commit eb26dfe8aa7e ("8250: add support for ASIX devices with a FIFO
bug") merged on Jul 13, 2012 adds a quirk for PCI_VENDOR_ID_ASIX
(0x9710). But that ID is the same as PCI_VENDOR_ID_NETMOS defined in
1f8b061050c7 ("[PATCH] Netmos parallel/serial/combo support") merged
on Mar 28, 2005. In pci_serial_quirks array, the NetMos entry always
takes precedence over the ASIX entry even since it was initially
merged, code in that commit is always unreachable.
In my tests, adding the FIFO workaround to pci_netmos_init() makes no
difference, and the vendor driver also does not have such workaround.
Given that the code was never used for over a decade, it's safe to
revert it.
Also, the real PCI_VENDOR_ID_ASIX should be 0x125b, which is used on
their newer AX99100 PCIe serial controllers released on 2016. The FIFO
workaround should not be intended for these newer controllers, and it
was never implemented in vendor driver.
Fixes: eb26dfe8aa7e ("8250: add support for ASIX devices with a FIFO bug")
Cc: stable <stable@kernel.org>
Signed-off-by: Jiaqing Zhao <jiaqing.zhao@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230619155743.827859-1-jiaqing.zhao@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There's a potential race before THRE/TEMT deasserts when DMA Tx is
starting up (or the next batch of continuous Tx is being submitted).
This can lead to misdetecting Tx empty condition.
It is entirely normal for THRE/TEMT to be set for some time after the
DMA Tx had been setup in serial8250_tx_dma(). As Tx side is definitely
not empty at that point, it seems incorrect for serial8250_tx_empty()
claim Tx is empty.
Fix the race by also checking in serial8250_tx_empty() whether there's
DMA Tx active.
Note: This fix only addresses in-kernel race mainly to make using
TCSADRAIN/FLUSH robust. Userspace can still cause other races but they
seem userspace concurrency control problems.
Fixes: 9ee4b83e51f74 ("serial: 8250: Add support for dmaengine")
Cc: stable@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230317113318.31327-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 146a37e05d620cef4ad430e5d1c9c077fe6fa76f)
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 0ba9e3a13c6adfa99e32b2576d20820ab10ad48a ]
An 8250 UART configured as a wake-up source would not have reported
itself through sysfs as being the source of wake-up, correct that.
Fixes: b3b708fa2780 ("wake up from a serial port")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230414170241.2016255-1-f.fainelli@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 1980860e0c8299316cddaf0992dd9e1258ec9d88 upstream.
Returning true from handle_rx_dma() without flushing DMA first creates
a data ordering hazard. If DMA Rx has handled any character at the
point when RLSI occurs, the non-DMA path handles any pending characters
jumping them ahead of those characters that are pending under DMA.
Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221108121952.5497-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a931237cbea256aff13bb403da13a97b2d1605d9 upstream.
DW UART sometimes triggers IIR_RDI during DMA Rx when IIR_RX_TIMEOUT
should have been triggered instead. Since IIR_RDI has higher priority
than IIR_RX_TIMEOUT, this causes the Rx to hang into interrupt loop.
The problem seems to occur at least with some combinations of
small-sized transfers (I've reproduced the problem on Elkhart Lake PSE
UARTs).
If there's already an on-going Rx DMA and IIR_RDI triggers, fall
graciously back to non-DMA Rx. That is, behave as if IIR_RX_TIMEOUT had
occurred.
8250_omap already considers IIR_RDI similar to this change so its
nothing unheard of.
Fixes: 75df022b5f89 ("serial: 8250_dma: Fix RX handling")
Cc: <stable@vger.kernel.org>
Co-developed-by: Srikanth Thokala <srikanth.thokala@intel.com>
Signed-off-by: Srikanth Thokala <srikanth.thokala@intel.com>
Co-developed-by: Aman Kumar <aman.kumar@intel.com>
Signed-off-by: Aman Kumar <aman.kumar@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221108121952.5497-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 379a33786d489ab81885ff0b3935cfeb36137fea ]
Since commit edc6afc54968 ("tty: switch to ktermios and new framework")
termios speed is no longer stored only in c_cflag member but also in new
additional c_ispeed and c_ospeed members. If BOTHER flag is set in c_cflag
then termios speed is stored only in these new members.
Since commit 027b57170bf8 ("serial: core: Fix initializing and restoring
termios speed") termios speed is available also in struct console.
So properly restore also c_ispeed and c_ospeed members after suspend to fix
restoring termios speed which is not represented by Bnnn constant.
Fixes: 4516d50aabed ("serial: 8250: Use canary to restart console after suspend")
Signed-off-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/20220924104324.4035-1-pali@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 6e690d54cfa802f939cefbd2fa2c91bd0b8bd1b6 upstream.
If port->mapbase = NULL in serial8250_request_std_resource() , it need
return a error code instead of 0. If uart_set_info() fail to request new
regions by serial8250_request_std_resource() but the return value of
serial8250_request_std_resource() is 0, The system incorrectly considers
that the resource application is successful and does not attempt to
restore the old setting. A null pointer reference is triggered when the
port resource is later invoked.
Signed-off-by: Yi Yang <yiyang13@huawei.com>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20220628083515.64138-1-yiyang13@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit be03b0651ffd8bab69dfd574c6818b446c0753ce upstream.
Not all LSR register flags are preserved across reads. Therefore, LSR
readers must store the non-preserved bits into lsr_save_flags.
This fix was initially mixed into feature commit f6f586102add ("serial:
8250: Handle UART without interrupt on TEMT using em485"). However,
that feature change had a flaw and it was reverted to make room for
simpler approach providing the same feature. The embedded fix got
reverted with the feature change.
Re-add the lsr_save_flags fix and properly mark it's a fix.
Link: https://lore.kernel.org/all/1d6c31d-d194-9e6a-ddf9-5f29af829f3@linux.intel.com/T/#m1737eef986bd20cf19593e344cebd7b0244945fc
Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
Cc: stable <stable@kernel.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@penugtronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/f4d774be-1437-a550-8334-19d8722ab98c@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6e6eebdf5e2455f089ccd000754a0deaeb79af82 upstream.
Sticky MCR bits are lost in console restoration if console suspending
has been disabled. This currently affects the AFE bit, which works in
combination with RTS which we set, so we want to make sure the UART
retains control of its FIFO where previously requested. Also specific
drivers may need other bits in the future.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Fixes: 4516d50aabed ("serial: 8250: Use canary to restart console after suspend")
Cc: stable@vger.kernel.org # v4.0+
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181518490.9383@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit dedab69fd650ea74710b2e626e63fd35584ef773 ]
Set em485->active_timer = NULL isn't always enough to take out the stop
timer. While there is a check that it acts in the right state (i.e.
waiting for RTS-after-send to pass after sending some chars) but the
following might happen:
- CPU1: some chars send, shifter becomes empty, stop tx timer armed
- CPU0: more chars send before RTS-after-send expired
- CPU0: shifter empty irq, port lock taken
- CPU1: tx timer triggers, waits for port lock
- CPU0: em485->active_timer = &em485->stop_tx_timer, hrtimer_start(),
releases lock()
- CPU1: get lock, see em485->active_timer == &em485->stop_tx_timer,
tear down RTS too early
This fix bases on research done by Steffen Trumtrar.
Fixes: b86f86e8e7c5 ("serial: 8250: fix potential deadlock in rs485-mode")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20220215160236.344236-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit d7aff291d069c4418285f3c8ee27b0ff67ce5998 ]
Oxford Semiconductor 950 serial port devices have a 128-byte FIFO and in
the enhanced (650) mode, which we select in `autoconfig_has_efr' with
the ECB bit set in the EFR register, they support the receive interrupt
trigger level selectable with FCR bits 7:6 from the set of 16, 32, 112,
120. This applies to the original OX16C950 discrete UART[1] as well as
950 cores embedded into more complex devices.
For these devices we set the default to 112, which sets an excessively
high level of 112 or 7/8 of the FIFO capacity, unlike with other port
types where we choose at most 1/2 of their respective FIFO capacities.
Additionally we don't make the trigger level configurable. Consequently
frequent input overruns happen with high bit rates where hardware flow
control cannot be used (e.g. terminal applications) even with otherwise
highly-performant systems.
Lower the default receive interrupt trigger level to 32 then, and make
it configurable. Document the trigger levels along with other port
types, including the set of 16, 32, 64, 112 for the transmit interrupt
as well[2].
References:
[1] "OX16C950 rev B High Performance UART with 128 byte FIFOs", Oxford
Semiconductor, Inc., DS-0031, Sep 05, Table 10: "Receiver Trigger
Levels", p. 22
[2] same, Table 9: "Transmit Interrupt Trigger Levels", p. 22
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106260608480.37803@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit e5227c51090e165db4b48dcaa300605bfced7014 upstream.
Make sure only actual 8 bits of the IIR register are used in determining
the port type in `autoconfig'.
The `serial_in' port accessor returns the `unsigned int' type, meaning
that with UPIO_AU, UPIO_MEM16, UPIO_MEM32, and UPIO_MEM32BE access types
more than 8 bits of data are returned, of which the high order bits will
often come from bus lines that are left floating in the data phase. For
example with the MIPS Malta board's CBUS UART, where the registers are
aligned on 8-byte boundaries and which uses 32-bit accesses, data as
follows is returned:
YAMON> dump -32 0xbf000900 0x40
BF000900: 1F000942 1F000942 1F000900 1F000900 ...B...B........
BF000910: 1F000901 1F000901 1F000900 1F000900 ................
BF000920: 1F000900 1F000900 1F000960 1F000960 ...........`...`
BF000930: 1F000900 1F000900 1F0009FF 1F0009FF ................
YAMON>
Evidently high-order 24 bits return values previously driven in the
address phase (the 3 highest order address bits used with the command
above are masked out in the simple virtual address mapping used here and
come out at zeros on the external bus), a common scenario with bus lines
left floating, due to bus capacitance.
Consequently when the value of IIR, mapped at 0x1f000910, is retrieved
in `autoconfig', it comes out at 0x1f0009c1 and when it is right-shifted
by 6 and then assigned to 8-bit `scratch' variable, the value calculated
is 0x27, not one of 0, 1, 2, 3 expected in port type determination.
Fix the issue then, by assigning the value returned from `serial_in' to
`scratch' first, which masks out 24 high-order bits retrieved, and only
then right-shift the resulting 8-bit data quantity, producing the value
of 3 in this case, as expected. Fix the same issue in `serial_dl_read'.
The problem first appeared with Linux 2.6.9-rc3 which predates our repo
history, but the origin could be identified with the old MIPS/Linux repo
also at: <git://git.kernel.org/pub/scm/linux/kernel/git/ralf/linux.git>
as commit e0d2356c0777 ("Merge with Linux 2.6.9-rc3."), where code in
`serial_in' was updated with this case:
+ case UPIO_MEM32:
+ return readl(up->port.membase + offset);
+
which made it produce results outside the unsigned 8-bit range for the
first time, though obviously it is system dependent what actual values
appear in the high order bits retrieved and it may well have been zeros
in the relevant positions with the system the change originally was
intended for. It is at that point that code in `autoconf' should have
been updated accordingly, but clearly it was overlooked.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org # v2.6.12+
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106260516220.37803@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 78bcae8616ac277d6cb7f38e211493948ed73e30 ]
Support for magic baud rate divisors of 32770 and 32769 used with SMSC
Super I/O chips for extra baud rates of 230400 and 460800 respectively
where base rate is 115200[1] has been added around Linux 2.5.64, which
predates our repo history, but the origin could be identified as commit
2a717aad772f ("Merge with Linux 2.5.64.") with the old MIPS/Linux repo
also at: <git://git.kernel.org/pub/scm/linux/kernel/git/ralf/linux.git>.
Code that is now in `serial8250_do_get_divisor' was added back then to
`serial8250_get_divisor', but that code would only ever trigger if one
of the higher baud rates was actually requested, and that cannot ever
happen, because the earlier call to `serial8250_get_baud_rate' never
returns them. This is because it calls `uart_get_baud_rate' with the
maximum requested being the base rate, that is clk/16 or 115200 for SMSC
chips at their nominal clock rate.
Fix it then and allow UPF_MAGIC_MULTIPLIER baud rates to be selected, by
requesting the maximum baud rate of clk/4 rather than clk/16 if the flag
has been set. Also correct the minimum baud rate, observing that these
ports only support actual (non-magic) divisors of up to 32767 only.
References:
[1] "FDC37M81x, PC98/99 Compliant Enhanced Super I/O Controller with
Keyboard/Mouse Wake-Up", Standard Microsystems Corporation, Rev.
03/27/2000, Table 31 - "Baud Rates", p. 77
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2105190412280.29169@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f19c3f6c8109b8bab000afd35580929958e087a9 ]
When port's throttle callback is called, it should stop pushing any more
data into TTY buffer to avoid buffer overflow. This means driver has to
stop HW from receiving more data and assert the HW flow control. For
UARTs with auto HW flow control (such as 8250_omap) manual assertion of
flow control line is not possible and only way is to allow RX FIFO to
fill up, thus trigger auto HW flow control logic.
Therefore make sure that 8250 generic IRQ handler does not drain data
when port is stopped (i.e UART_LSR_DR is unset in read_status_mask). Not
servicing, RX FIFO would trigger auto HW flow control when FIFO
occupancy reaches preset threshold, thus halting RX.
Since, error conditions in UART_LSR register are cleared just by reading
the register, data has to be drained in case there are FIFO errors, else
error information will lost.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200319103230.16867-2-vigneshr@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 205d300aea75623e1ae4aa43e0d265ab9cf195fd upstream.
We have a number of "uart.port->desc.lock vs desc.lock->uart.port"
lockdep reports coming from 8250 driver; this causes a bit of trouble
to people, so let's fix it.
The problem is reverse lock order in two different call paths:
chain #1:
serial8250_do_startup()
spin_lock_irqsave(&port->lock);
disable_irq_nosync(port->irq);
raw_spin_lock_irqsave(&desc->lock)
chain #2:
__report_bad_irq()
raw_spin_lock_irqsave(&desc->lock)
for_each_action_of_desc()
printk()
spin_lock_irqsave(&port->lock);
Fix this by changing the order of locks in serial8250_do_startup():
do disable_irq_nosync() first, which grabs desc->lock, and grab
uart->port after that, so that chain #1 and chain #2 have same lock
order.
Full lockdep splat:
======================================================
WARNING: possible circular locking dependency detected
5.4.39 #55 Not tainted
======================================================
swapper/0/0 is trying to acquire lock:
ffffffffab65b6c0 (console_owner){-...}, at: console_lock_spinning_enable+0x31/0x57
but task is already holding lock:
ffff88810a8e34c0 (&irq_desc_lock_class){-.-.}, at: __report_bad_irq+0x5b/0xba
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&irq_desc_lock_class){-.-.}:
_raw_spin_lock_irqsave+0x61/0x8d
__irq_get_desc_lock+0x65/0x89
__disable_irq_nosync+0x3b/0x93
serial8250_do_startup+0x451/0x75c
uart_startup+0x1b4/0x2ff
uart_port_activate+0x73/0xa0
tty_port_open+0xae/0x10a
uart_open+0x1b/0x26
tty_open+0x24d/0x3a0
chrdev_open+0xd5/0x1cc
do_dentry_open+0x299/0x3c8
path_openat+0x434/0x1100
do_filp_open+0x9b/0x10a
do_sys_open+0x15f/0x3d7
kernel_init_freeable+0x157/0x1dd
kernel_init+0xe/0x105
ret_from_fork+0x27/0x50
-> #1 (&port_lock_key){-.-.}:
_raw_spin_lock_irqsave+0x61/0x8d
serial8250_console_write+0xa7/0x2a0
console_unlock+0x3b7/0x528
vprintk_emit+0x111/0x17f
printk+0x59/0x73
register_console+0x336/0x3a4
uart_add_one_port+0x51b/0x5be
serial8250_register_8250_port+0x454/0x55e
dw8250_probe+0x4dc/0x5b9
platform_drv_probe+0x67/0x8b
really_probe+0x14a/0x422
driver_probe_device+0x66/0x130
device_driver_attach+0x42/0x5b
__driver_attach+0xca/0x139
bus_for_each_dev+0x97/0xc9
bus_add_driver+0x12b/0x228
driver_register+0x64/0xed
do_one_initcall+0x20c/0x4a6
do_initcall_level+0xb5/0xc5
do_basic_setup+0x4c/0x58
kernel_init_freeable+0x13f/0x1dd
kernel_init+0xe/0x105
ret_from_fork+0x27/0x50
-> #0 (console_owner){-...}:
__lock_acquire+0x118d/0x2714
lock_acquire+0x203/0x258
console_lock_spinning_enable+0x51/0x57
console_unlock+0x25d/0x528
vprintk_emit+0x111/0x17f
printk+0x59/0x73
__report_bad_irq+0xa3/0xba
note_interrupt+0x19a/0x1d6
handle_irq_event_percpu+0x57/0x79
handle_irq_event+0x36/0x55
handle_fasteoi_irq+0xc2/0x18a
do_IRQ+0xb3/0x157
ret_from_intr+0x0/0x1d
cpuidle_enter_state+0x12f/0x1fd
cpuidle_enter+0x2e/0x3d
do_idle+0x1ce/0x2ce
cpu_startup_entry+0x1d/0x1f
start_kernel+0x406/0x46a
secondary_startup_64+0xa4/0xb0
other info that might help us debug this:
Chain exists of:
console_owner --> &port_lock_key --> &irq_desc_lock_class
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&irq_desc_lock_class);
lock(&port_lock_key);
lock(&irq_desc_lock_class);
lock(console_owner);
*** DEADLOCK ***
2 locks held by swapper/0/0:
#0: ffff88810a8e34c0 (&irq_desc_lock_class){-.-.}, at: __report_bad_irq+0x5b/0xba
#1: ffffffffab65b5c0 (console_lock){+.+.}, at: console_trylock_spinning+0x20/0x181
stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.39 #55
Hardware name: XXXXXX
Call Trace:
<IRQ>
dump_stack+0xbf/0x133
? print_circular_bug+0xd6/0xe9
check_noncircular+0x1b9/0x1c3
__lock_acquire+0x118d/0x2714
lock_acquire+0x203/0x258
? console_lock_spinning_enable+0x31/0x57
console_lock_spinning_enable+0x51/0x57
? console_lock_spinning_enable+0x31/0x57
console_unlock+0x25d/0x528
? console_trylock+0x18/0x4e
vprintk_emit+0x111/0x17f
? lock_acquire+0x203/0x258
printk+0x59/0x73
__report_bad_irq+0xa3/0xba
note_interrupt+0x19a/0x1d6
handle_irq_event_percpu+0x57/0x79
handle_irq_event+0x36/0x55
handle_fasteoi_irq+0xc2/0x18a
do_IRQ+0xb3/0x157
common_interrupt+0xf/0xf
</IRQ>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Fixes: 768aec0b5bcc ("serial: 8250: fix shared interrupts issues with SMP and RT kernels")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: Raul Rangel <rrangel@google.com>
BugLink: https://bugs.chromium.org/p/chromium/issues/detail?id=1114800
Link: https://lore.kernel.org/lkml/CAHQZ30BnfX+gxjPm1DUd5psOTqbyDh4EJE=2=VAMW_VDafctkA@mail.gmail.com/T/#u
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200817022646.1484638-1-sergey.senozhatsky@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 7b668c064ec33f3d687c3a413d05e355172e6c92 ]
Standard 8250 UART ports are designed in a way so they can communicate
with baud rates up to 1/16 of a reference frequency. It's expected from
most of the currently supported UART controllers. That's why the former
version of serial8250_get_baud_rate() method called uart_get_baud_rate()
with min and max baud rates passed as (port->uartclk / 16 / UART_DIV_MAX)
and ((port->uartclk + tolerance) / 16) respectively. Doing otherwise, like
it was suggested in commit ("serial: 8250_mtk: support big baud rate."),
caused acceptance of bauds, which was higher than the normal UART
controllers actually supported. As a result if some user-space program
requested to set a baud greater than (uartclk / 16) it would have been
permitted without truncation, but then serial8250_get_divisor(baud)
(which calls uart_get_divisor() to get the reference clock divisor) would
have returned a zero divisor. Setting zero divisor will cause an
unpredictable effect varying from chip to chip. In case of DW APB UART the
communications just stop.
Lets fix this problem by getting back the limitation of (uartclk +
tolerance) / 16 maximum baud supported by the generic 8250 port. Mediatek
8250 UART ports driver developer shouldn't have touched it in the first
place notably seeing he already provided a custom version of set_termios()
callback in that glue-driver which took into account the extended baud
rate values and accordingly updated the standard and vendor-specific
divisor latch registers anyway.
Fixes: 81bb549fdf14 ("serial: 8250_mtk: support big baud rate.")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Long Cheng <long.cheng@mediatek.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-mips@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mediatek@lists.infradead.org
Link: https://lore.kernel.org/r/20200506233136.11842-2-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 7febbcbc48fc92e3f33863b32ed715ba4aff18c4 upstream.
The commit 54e53b2e8081
("tty: serial: 8250: pass IRQ shared flag to UART ports")
nicely explained the problem:
---8<---8<---
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 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 routines 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 stack trace 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
---8<---8<---
But unfortunately didn't fix the root cause. Let's try again here by moving
IRQ flag assignment from serial_link_irq_chain() to serial8250_do_startup().
This should fix the similar issue reported for 8250_pnp case.
Since this change we don't need to have custom solutions in 8250_aspeed_vuart
and 8250_of drivers, thus, drop them.
Fixes: 1c2f04937b3e ("serial: 8250: add IRQ trigger support")
Reported-by: Li RongQing <lirongqing@baidu.com>
Cc: Kurt Kanzenbach <kurt@linutronix.de>
Cc: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Kurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20200211135559.85960-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add support to Sunix serial boards with up to 16 ports.
Sunix board need its own setup callback instead of using Timedia's, to
properly support more than 4 ports.
Cc: Morris Ku <morris_ku@sunix.com>
Cc: Debbie Liu <debbie_liu@sunix.com>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20190809190130.30773-1-kai.heng.feng@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Move INT0 clearing out of common, per-port serial8250_do_startup()
into PCI device probe/resume.
As described in commit 2c0ac5b48a35 ("serial: exar: Fix stuck MSIs"),
the purpose of clearing INT0 is to prevent the PCI interrupt line from
becoming stuck asserted, "which is fatal with edge-triggered MSIs".
Like the clearing via interrupt handler that moved from common code in
commit c7e1b4059075 ("tty: serial: exar: Relocate sleep wake-up
handling"), this clearing at startup can be better handled at the PCI
device level.
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190801185956.3222-1-asierra@xes-inc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There are Exar custom divisor support in 8250_port which belongs to
8250_exar module. Move it out to the correct module and do not contaminate
generic code with it.
Cc: Aaron Sierra <asierra@xes-inc.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190731170558.52897-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There are Exar quirks in 8250_port which belong to 8250_exar module.
Extract PM routine to the correct module and do not contaminate generic code
with it.
Cc: Aaron Sierra <asierra@xes-inc.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190731170558.52897-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Since we have a separate driver there is no need to autoconfigure ports,
we already know what they are.
Drop autoconfiguration in 8250_port and move type detection to 8250_exar.
Cc: Aaron Sierra <asierra@xes-inc.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190731170558.52897-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit 2e9fe539108320820016f78ca7704a7342788380.
Reading LSR unconditionally but processing the error flags only if
UART_IIR_RDI bit was set before in IIR may lead to a loss of transmission
error information on UARTs where the transmission error flags are cleared
by a read of LSR. Information are lost in case an error is detected right
before the read of LSR while processing e.g. an UART_IIR_THRI interrupt.
Signed-off-by: Oliver Barta <o.barta89@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: 2e9fe5391083 ("serial: 8250: Don't service RX FIFO if interrupts are disabled")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch permits the usage for GPIOs to control
the CTS/RTS/DTR/DSR/DCD/RI signals.
Changed by Stefan:
Only call mctrl_gpio_init(), if the device has no ACPI companion device
to not break existing ACPI based systems. Also only use the mctrl_gpio_
functions when "gpios" is available.
Use MSR / MCR <-> TIOCM wrapper functions.
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Yegor Yefremov <yegorslists@googlemail.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Giulio Benetti <giulio.benetti@micronovasrl.com>
Cc: Yegor Yefremov <yegorslists@googlemail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch adds wrapper functions to convert MSR <-> TIOCM and also
MCR <-> TIOCM. These functions are used now in serial8250_do_set_mctrl()
and serial8250_do_get_mctrl().
Signed-off-by: Stefan Roese <sr@denx.de>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Yegor Yefremov <yegorslists@googlemail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Giulio Benetti <giulio.benetti@micronovasrl.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Factor out similar code pieces that set or clear UART_IER_THRI bit to
serial8250_{set,clear}_THRI() helpers.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Interrupt handler checked THRE bit (transmitter holding register
empty) in LSR to detect if TX fifo is empty.
In case when there is only receive interrupts the TX handling
got called because THRE bit in LSR is set when there is no
transmission (FIFO empty). TX handling caused TX stop, which in
RS-485 half-duplex mode actually resets receiver FIFO. This is not
desired during reception because of possible data loss.
The fix is to check if THRI is set in IER in addition of the TX
fifo status. THRI in IER is set when TX is started and cleared
when TX is stopped.
This ensures that TX handling is only called when there is really
transmission on going and an interrupt for THRE and not when there
are only RX interrupts.
Signed-off-by: Kimmo Rautkoski <ext-kimmo.rautkoski@vaisala.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial driver updates from Greg KH:
"Here is the large TTY/Serial driver set of patches for 4.21-rc1.
A number of small serial driver changes along with some good tty core
fixes for long-reported issues with locking. There is also a new
console font added to the tree, for high-res screens, so that should
be helpful for many.
The last patch in the series is a revert of an older one in the tree,
it came late but it resolves a reported issue that linux-next was
having for some people.
Full details are in the shortlog, and all of these, with the exception
of the revert, have been in linux-next for a while with no reported
issues"
* tag 'tty-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (85 commits)
Revert "serial: 8250: Default SERIAL_OF_PLATFORM to SERIAL_8250"
serial: sccnxp: Allow to use non-standard baud rates
serial: sccnxp: Adds a delay between sequential read/write cycles
tty: serial: qcom_geni_serial: Fix UART hang
tty: serial: qcom_geni_serial: Fix wrap around of TX buffer
serial: max310x: Fix tx_empty() callback
dt-bindings: serial: sh-sci: Document r8a774c0 bindings
dt-bindings: serial: sh-sci: Document r8a774a1 bindings
Fonts: New Terminus large console font
dt-bindings: serial: lpuart: add imx8qxp compatible string
serial: uartps: Fix interrupt mask issue to handle the RX interrupts properly
serial: uartps: Fix error path when alloc failed
serial: uartps: Check if the device is a console
serial: uartps: Add the device_init_wakeup
tty: serial: samsung: Increase maximum baudrate
tty: serial: samsung: Properly set flags in autoCTS mode
tty: Use of_node_name_{eq,prefix} for node name comparisons
tty/serial: do not free trasnmit buffer page under port lock
serial: 8250: Rate limit serial port rx interrupts during input overruns
dt-bindings: serial: 8250: Add rate limit for serial port input overruns
...
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Commit f6aa5beb45be ("serial: 8250: Fix clearing FIFOs in RS485 mode
again") makes a change to FIFO clearing code which its commit message
suggests was intended to be specific to use with RS485 mode, however:
1) The change made does not just affect __do_stop_tx_rs485(), it also
affects other uses of serial8250_clear_fifos() including paths for
starting up, shutting down or auto-configuring a port regardless of
whether it's an RS485 port or not.
2) It makes the assumption that resetting the FIFOs is a no-op when
FIFOs are disabled, and as such it checks for this case & explicitly
avoids setting the FIFO reset bits when the FIFO enable bit is
clear. A reading of the PC16550D manual would suggest that this is
OK since the FIFO should automatically be reset if it is later
enabled, but we support many 16550-compatible devices and have never
required this auto-reset behaviour for at least the whole git era.
Starting to rely on it now seems risky, offers no benefit, and
indeed breaks at least the Ingenic JZ4780's UARTs which reads
garbage when the RX FIFO is enabled if we don't explicitly reset it.
3) By only resetting the FIFOs if they're enabled, the behaviour of
serial8250_do_startup() during boot now depends on what the value of
FCR is before the 8250 driver is probed. This in itself seems
questionable and leaves us with FCR=0 & no FIFO reset if the UART
was used by 8250_early, otherwise it depends upon what the
bootloader left behind.
4) Although the naming of serial8250_clear_fifos() may be unclear, it
is clear that callers of it expect that it will disable FIFOs. Both
serial8250_do_startup() & serial8250_do_shutdown() contain comments
to that effect, and other callers explicitly re-enable the FIFOs
after calling serial8250_clear_fifos(). The premise of that patch
that disabling the FIFOs is incorrect therefore seems wrong.
For these reasons, this reverts commit f6aa5beb45be ("serial: 8250: Fix
clearing FIFOs in RS485 mode again").
Signed-off-by: Paul Burton <paul.burton@mips.com>
Fixes: f6aa5beb45be ("serial: 8250: Fix clearing FIFOs in RS485 mode again").
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Daniel Jedrychowski <avistel@gmail.com>
Cc: Marek Vasut <marex@denx.de>
Cc: linux-mips@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Cc: stable <stable@vger.kernel.org> # 4.10+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Let's take advantage of the new ("serial: core: Allow processing sysrq
at port unlock time") to handle sysrqs more cleanly.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The 8250 FIFOs indeed need to be cleared after stopping transmission in
RS485 mode without SER_RS485_RX_DURING_TX flag set. But there are two
problems with the approach taken by the previous patch from Fixes tag.
First, serial8250_clear_fifos() should clear fifos, but what it really
does is it enables the FIFOs unconditionally if present, clears them
and then sets the FCR register to zero, which effectively disables the
FIFOs. In case the FIFO is disabled, enabling it and clearing it makes
no sense and in fact can trigger misbehavior of the 8250 core. Moreover,
the FCR register may contain other FIFO configuration bits which may not
be writable unconditionally and writing them incorrectly can trigger
misbehavior of the 8250 core too. (ie. AM335x UART swallows the first
byte and retransmits the last byte twice because of this FCR write).
Second, serial8250_clear_and_reinit_fifos() completely reloads the FCR,
but what really has to happen at the end of the RS485 transmission is
clearing of the FIFOs and nothing else.
This patch repairs serial8250_clear_fifos() so that it really only
clears the FIFOs by operating on FCR[2:1] bits and leaves all the
other bits alone. It also undoes serial8250_clear_and_reinit_fifos()
from __do_stop_tx_rs485() as serial8250_clear_fifos() is sufficient.
Signed-off-by: Marek Vasut <marex@denx.de>
Fixes: 2bed8a8e7072 ("Clearing FIFOs in RS485 emulation mode causes subsequent transmits to break")
Cc: Daniel Jedrychowski <avistel@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org> # let it bake a bit before merging
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revert commit ecb988a3b7985913d1f0112f66667cdd15e40711: tty: serial:
8250: 8250_core: NXP SC16C2552 workaround
The above commit causes userland application to no longer write
correctly its first write to a dumb terminal connected to /dev/ttyS0.
This commit seems to be the culprit. It's as though the TX FIFO is being
reset during that write. What should be displayed is:
PSW 80000000 INST 00000000 HALT
//
What is displayed is some variation of:
T 00000000 HAL//
Reverting this commit via this patch fixes my problem.
Signed-off-by: Mark Hounschell <dmarkh@cfl.rr.com>
Fixes: ecb988a3b798 ("tty: serial: 8250: 8250_core: NXP SC16C2552 workaround")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Since we have port name stored in struct uart_port, we better to use
that one instead of open coding.
This will make it one place source for easier maintenance or
modifications.
While here, replace printk_ratelimited(KERN_INFO ) by pr_info_ratelimited().
It seems last printk() call in 8250_port.c.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Some drivers could call serial8250_do_set_divisor() to complete its
own set_divisor routine. Export this symbol for code reusing.
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add these two hooks so that they can be overridden with driver specific
implementations.
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Align serial8250_get_divisor() with serial8250_set_divisor() to accept
uart_port pointer as the first parameter. No functionality changes.
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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>
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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>
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The Nuvoton UART is almost compatible with the 8250 driver when probed
via the 8250_of driver, however it requires some extra configuration
at startup.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Currently, data in RX FIFO is read based on UART_LSR register state even
if RDI and RLSI interrupts are disabled in UART_IER register.
This is because when IRQ handler is called due to TX FIFO empty event,
RX FIFO is serviced based on UART_LSR register status instead of
UART_IIR status. This defeats the purpose of disabling UART RX
FIFO interrupts during throttling(see, omap_8250_throttle()) as IRQ
handler continues to drain UART RX FIFO resulting in overflow of buffer
at tty layer.
Fix this by making sure that driver drains UART RX FIFO only when
UART_IIR_RDI is set along with UART_LSR_BI or UART_LSR_DR bits.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Exar sleep wake-up handling has been done on a per-channel basis by
virtue of INT0 being accessible from each channel's address space. I
believe this was initially done out of necessity, but now that Exar
devices have their own driver, we can do things more efficiently by
registering a dedicated INT0 handler at the PCI device level.
I see this change providing the following benefits:
1. If more than one port is active, eliminates the redundant bus
cycles for reading INT0 on every interrupt.
2. This note associated with hooking in the per-channel handler in
8250_port.c is resolved:
/* Fixme: probably not the best place for this */
Cc: Matt Schulte <matts@commtech-fastcom.com>
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Now that the SPDX tag is in all tty files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.
This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.
No copyright headers or other non-license-description text was removed.
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Pat Gefre <pfg@sgi.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@tabi.org>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.
Update the drivers/tty files files with the correct SPDX license
identifier based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.
This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: "Uwe Kleine-König" <kernel@pengutronix.de>
Cc: Pat Gefre <pfg@sgi.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@tabi.org>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Canceling hrtimer when holding uart spinlock can deadlock.
CPU0: syscall write
-> get uart port spinlock
-> write uart
-> start_tx_rs485
-> hrtimer_cancel
-> wait for hrtimer callback to finish
CPU1: hrtimer IRQ
-> run hrtimer
-> em485_handle_stop_tx
-> get uart port spinlock
CPU0 is waiting for the hrtimer callback to finish, but the hrtimer
callback running on CPU1 is waiting to get the uart port spinlock.
This deadlock can be avoided by not canceling the hrtimers in these paths.
Setting active_timer=NULL can be done without accessing hrtimer,
and that will effectively cancel operations that would otherwise have been
performed by the hrtimer callback.
Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The upper four bits of the XR17V35x fractional divisor register (DLD)
control general chip function (RS-485 direction pin polarity, multidrop
mode, XON/XOFF parity check, and fast IR mode). Don't allow these bits
to be clobbered when setting the baudrate.
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add a define for the maximum baud rate divisor, to improve code
readability.
Signed-off-by: Ed Blake <ed.blake@sondrel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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After switching to HR timers for RS485 the NULL checks for the object
inside timer functions become useless.
Remove them to avoid confusion to static analyzers.
Fixes 6e0a5de2136b ("serial: 8250: Use hrtimers for rs485 delays")
Cc: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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MT7622/23 SoC
MediaTek BTIF controller is the serial interface similar to UART but it
works only as the digital device which is mainly used to communicate with
the connectivity module called CONNSYS inside the SoC which could be mostly
found on those MediaTek SoCs with Bluetooth feature such as MT7622 and
MT7623 SoCs.
And the controller is made as being compatible with the 8250 register
layout with extra registers such as DMA enablement so it tends to be
integrated with reusing 8250 OF driver. However, DMA mode is not being
supported yet in the current driver.
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Andy Shevchenko
Tony Lindgren
Jiaqing Zhao
Ilpo Järvinen
Florian Fainelli
Pali Rohár
Yi Yang
Maciej W. Rozycki
Uwe Kleine-König
Vignesh Raghavendra
Sergey Senozhatsky
Serge Semin
Kai-Heng Feng
Aaron Sierra
Oliver Barta
Yegor Yefremov
Stefan Roese
Rautkoski Kimmo EXT
Linus Torvalds
Paul Burton
Douglas Anderson
Marek Vasut
Mark
Jisheng Zhang
Jeremy Kerr
Joel Stanley
Greg Kroah-Hartman
Tomas Melin
Ed Blake
Sean Wang