OpenCloudOS-Kernel/drivers
Andy Shevchenko 7febbcbc48 serial: 8250: Check UPF_IRQ_SHARED in advance
The commit 54e53b2e80
  ("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: 1c2f04937b ("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>
2020-02-12 11:56:44 -08:00
..
accessibility
acpi Additional ACPI updates for 5.6-rc1 2020-02-07 12:51:54 -08:00
amba
android for-5.6/io_uring-vfs-2020-01-29 2020-01-29 18:53:37 -08:00
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bus ARM: SoC-related driver updates 2020-02-08 14:04:19 -08:00
cdrom
char treewide: remove redundant IS_ERR() before error code check 2020-02-04 03:05:27 +00:00
clk ARM: SoC: late updates 2020-02-08 14:17:27 -08:00
clocksource ARM: SoC: late updates 2020-02-08 14:17:27 -08:00
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crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-01-28 16:02:33 -08:00
dax
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dma-buf
edac ioremap changes for 5.6 2020-01-27 13:03:00 -08:00
eisa
extcon
firewire
firmware ARM: SoC-related driver updates 2020-02-08 14:04:19 -08:00
fpga
fsi
gnss
gpio treewide: remove redundant IS_ERR() before error code check 2020-02-04 03:05:27 +00:00
gpu Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
greybus
hid drm pull for 5.6-rc1 2020-01-30 08:04:01 -08:00
hsi
hv - Most of the commits here are work to enable host-initiated hibernation 2020-02-03 14:42:03 +00:00
hwmon ARM: SoC-related driver updates 2020-02-08 14:04:19 -08:00
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hwtracing
i2c Merge branch 'i2c/for-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2020-02-07 12:54:13 -08:00
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idle intel_idle: Introduce 'states_off' module parameter 2020-02-03 11:57:18 +01:00
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infiniband RDMA subsystem updates for 5.6 2020-01-31 14:40:36 -08:00
input Merge branch 'akpm' (patches from Andrew) 2020-02-04 07:24:48 +00:00
interconnect
iommu IOMMU Updates for Linux v5.6 2020-02-05 17:49:54 +00:00
ipack
irqchip irqchip/gic-v4.1: Avoid 64bit division for the sake of 32bit ARM 2020-02-09 15:47:37 -08:00
isdn proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
leds leds: lm3532: add pointer to documentation and fix typo 2020-01-22 21:08:24 +01:00
lightnvm
macintosh powerpc updates for 5.6 2020-02-04 13:06:46 +00:00
mailbox
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memory
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mtd treewide: remove redundant IS_ERR() before error code check 2020-02-04 03:05:27 +00:00
mux
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ntb
nubus
nvdimm mm: Cleanup __put_devmap_managed_page() vs ->page_free() 2020-01-31 10:30:37 -08:00
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of ARM: SoC-related driver updates 2020-02-08 14:04:19 -08:00
opp ioremap changes for 5.6 2020-01-27 13:03:00 -08:00
oprofile
parisc proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
parport
pci pci-v5.6-fixes-1 2020-02-06 14:17:38 +00:00
pcmcia
perf
phy treewide: remove redundant IS_ERR() before error code check 2020-02-04 03:05:27 +00:00
pinctrl pinctrl: fix pxa2xx.c build warnings 2020-02-04 03:05:24 +00:00
platform Merge branch 'akpm' (patches from Andrew) 2020-02-04 07:24:48 +00:00
pnp proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
power ARM: SoC platform updates 2020-02-08 13:55:25 -08:00
powercap
pps
ps3
ptp Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net 2020-01-19 22:10:04 +01:00
pwm pwm: Remove set but not set variable 'pwm' 2020-01-20 15:40:49 +01:00
rapidio
ras
regulator - New Drivers 2020-02-03 14:51:57 +00:00
remoteproc remoteproc: qcom: q6v5-mss: Improve readability of reset_assert 2020-01-24 09:34:07 -08:00
reset
rpmsg rpmsg: add rpmsg support for mt8183 SCP. 2020-01-20 10:29:56 -08:00
rtc chrome platform changes for 5.6 2020-02-04 07:17:41 +00:00
s390 s390 updates for the 5.6 merge window #2 2020-02-05 17:33:35 +00:00
sbus
scsi SCSI misc on 20200208 2020-02-08 17:24:41 -08:00
sfi
sh
siox
slimbus
soc ARM: SoC-related driver updates 2020-02-08 14:04:19 -08:00
soundwire
spi treewide: remove redundant IS_ERR() before error code check 2020-02-04 03:05:27 +00:00
spmi
ssb
staging proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
target SCSI misc on 20200129 2020-01-29 18:16:16 -08:00
tc The main MIPS changes for 5.6: 2020-01-31 11:28:31 -08:00
tee ARM: SoC-related driver updates 2020-02-08 14:04:19 -08:00
thermal - Fix a SEVERE docs build failure for cpu idle cooling device (Randy Dunlap) 2020-01-31 14:39:21 -08:00
thunderbolt
tty serial: 8250: Check UPF_IRQ_SHARED in advance 2020-02-12 11:56:44 -08:00
uio
usb Merge branch 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-08 13:26:41 -08:00
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virt
virtio virtio_balloon: Fix memory leaks on errors in virtballoon_probe() 2020-02-06 03:40:27 -05:00
visorbus
vlynq
vme Char/Misc driver changes for 5.6-rc1 2020-01-29 10:35:54 -08:00
w1 Char/Misc driver changes for 5.6-rc1 2020-01-29 10:35:54 -08:00
watchdog linux-watchdog 5.6-rc1 tag 2020-02-07 12:30:16 -08:00
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