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Filename Latest commit message Latest commit date
Daniel Mack ce79cf407c serial: sc16is7xx: address RX timeout interrupt errata
commit 08ce9a1b72e38cf44c300a44ac5858533eb3c860 upstream.

This device has a silicon bug that makes it report a timeout interrupt
but no data in the FIFO.

The datasheet states the following in the errata section 18.1.4:

  "If the host reads the receive FIFO at the same time as a
  time-out interrupt condition happens, the host might read 0xCC
  (time-out) in the Interrupt Indication Register (IIR), but bit 0
  of the Line Status Register (LSR) is not set (means there is no
  data in the receive FIFO)."

The errata description seems to indicate it concerns only polled mode of
operation when reading bit 0 of the LSR register. However, tests have
shown and NXP has confirmed that the RXLVL register also yields 0 when
the bug is triggered, and hence the IRQ driven implementation in this
driver is equally affected.

This bug has hit us on production units and when it does, sc16is7xx_irq()
would spin forever because sc16is7xx_port_irq() keeps seeing an
interrupt in the IIR register that is not cleared because the driver
does not call into sc16is7xx_handle_rx() unless the RXLVL register
reports at least one byte in the FIFO.

Fix this by always reading one byte from the FIFO when this condition
is detected in order to clear the interrupt. This approach was
confirmed to be correct by NXP through their support channels.

Tested by: Hugo Villeneuve <hvilleneuve@dimonoff.com>

Signed-off-by: Daniel Mack <daniel@zonque.org>
Co-Developed-by: Maxim Popov <maxim.snafu@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231123072818.1394539-1-daniel@zonque.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-13 18:18:16 +01:00
arch arm64: dts: mediatek: mt8173-evb: Fix regulator-fixed node names 2023-12-13 18:18:15 +01:00
block block/partition: fix signedness issue for Amiga partitions 2023-07-27 08:37:29 +02:00
certs
crypto crypto: pcrypt - Fix hungtask for PADATA_RESET 2023-11-28 16:50:14 +00:00
Documentation firmware: ti_sci: Replace HTTP links with HTTPS ones 2023-11-20 10:30:12 +01:00
drivers serial: sc16is7xx: address RX timeout interrupt errata 2023-12-13 18:18:16 +01:00
fs nilfs2: prevent WARNING in nilfs_sufile_set_segment_usage() 2023-12-13 18:18:14 +01:00
include mmc: core: add helpers mmc_regulator_enable/disable_vqmmc 2023-12-13 18:18:15 +01:00
init x86/mm: Initialize text poking earlier 2023-08-08 19:56:36 +02:00
ipc
kernel perf: Fix perf_event_validate_size() 2023-12-13 18:18:15 +01:00
lib kobject: Fix slab-out-of-bounds in fill_kobj_path() 2023-11-08 11:23:38 +01:00
LICENSES
mm mm/cma: use nth_page() in place of direct struct page manipulation 2023-11-28 16:50:19 +00:00
net packet: Move reference count in packet_sock to atomic_long_t 2023-12-13 18:18:14 +01:00
samples samples/bpf: Fix buffer overflow in tcp_basertt 2023-07-27 08:37:07 +02:00
scripts kconfig: fix memory leak from range properties 2023-12-13 18:18:10 +01:00
security ima: detect changes to the backing overlay file 2023-12-08 08:44:27 +01:00
sound ALSA: pcm: fix out-of-bounds in snd_pcm_state_names 2023-12-13 18:18:14 +01:00
tools tools/power/turbostat: Fix a knl bug 2023-11-28 16:50:17 +00:00
usr
virt KVM: Destroy target device if coalesced MMIO unregistration fails 2023-03-11 16:44:01 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.263 2023-12-08 08:44:28 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.