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Filename Latest commit message Latest commit date
Zhiyong Tao 3b73a69962 serial: 8250_mtk: fix uart corruption issue when rx power off
commit 7c4a509d3815a260c423c0633bd73695250ac26d upstream.

Fix uart corruption issue when rx power off.
Add spin lock in mtk8250_dma_rx_complete function in APDMA mode.

when uart is used as a communication port with external device(GPS).
when external device(GPS) power off, the power of rx pin is also from
1.8v to 0v. Even if there is not any data in rx. But uart rx pin can
capture the data "0".
If uart don't receive any data in specified cycle, uart will generates
BI(Break interrupt) interrupt.
If external device(GPS) power off, we found that BI interrupt appeared
continuously and very frequently.
When uart interrupt type is BI, uart IRQ handler(8250 framwork
API:serial8250_handle_irq) will push data to tty buffer.
mtk8250_dma_rx_complete is a task of mtk_uart_apdma_rx_handler.
mtk8250_dma_rx_complete priority is lower than uart irq
handler(serial8250_handle_irq).
if we are in process of mtk8250_dma_rx_complete, uart appear BI
interrupt:1)serial8250_handle_irq will priority execution.2)it may cause
write tty buffer conflict in mtk8250_dma_rx_complete.
So the spin lock protect the rx receive data process is not break.

Signed-off-by: Zhiyong Tao <zhiyong.tao@mediatek.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210729084640.17613-2-zhiyong.tao@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-12 13:21:02 +02:00
arch mips: Fix non-POSIX regexp 2021-08-12 13:20:57 +02:00
block blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit() 2021-08-12 13:20:58 +02:00
certs
crypto
Documentation userfaultfd: do not untag user pointers 2021-07-28 13:31:01 +02:00
drivers serial: 8250_mtk: fix uart corruption issue when rx power off 2021-08-12 13:21:02 +02:00
fs ext4: fix potential htree corruption when growing large_dir directories 2021-08-12 13:21:02 +02:00
include tee: add tee_shm_alloc_kernel_buf() 2021-08-12 13:21:01 +02:00
init
ipc
kernel tracing / histogram: Give calculation hist_fields a size 2021-08-12 13:21:00 +02:00
lib lib/decompress_unlz4.c: correctly handle zero-padding around initrds. 2021-07-20 16:10:46 +02:00
LICENSES
mm mm: slab: fix kmem_cache_create failed when sysfs node not destroyed 2021-07-25 14:35:14 +02:00
net Bluetooth: defer cleanup of resources in hci_unregister_dev() 2021-08-12 13:20:58 +02:00
samples
scripts scripts/tracing: fix the bug that can't parse raw_trace_func 2021-08-12 13:21:00 +02:00
security
sound ALSA: usb-audio: Add registration quirk for JBL Quantum 600 2021-08-12 13:20:59 +02:00
tools bpf, selftests: Adjust few selftest outcomes wrt unreachable code 2021-08-08 09:04:09 +02:00
usr
virt KVM: add missing compat KVM_CLEAR_DIRTY_LOG 2021-08-04 12:27:37 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
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COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.139 2021-08-08 09:04:09 +02:00
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