src/sys/dev/uart/uart_dev_snps.c, branch stable/13

uart(4): Honor hardware state of NS8250-class for tsw_busy

2024-01-18T20:14:56+00:00

In 9750d9e5, I brought the equivalent of the TS_BUSY flag back in a
mostly hardware-agnostic way in order to fix tty_drain() and, thus,
TIOCDRAIN for UARTs with TX FIFOs. This proved to be sufficient for
fixing the regression reported. So in light of the release cycle of
FreeBSD 10.3, I decided that this change was be good enough for the
time being and opted to go with the smallest possible yet generic
(for all UARTs driven by uart(4)) solution addressing the problem at
hand.

However, at least for the NS8250-class the above isn't a complete
fix as these UARTs only trigger an interrupt when the TX FIFO became
empty. At this point, there still can be an outstanding character
left in the transmit shift register as indicated via the LSR. Thus,
this change adds the 3rd (besides the tty(4) and generic uart(4) bits)
part I had in my tree ever since, adding a uart_txbusy method to be
queried in addition for tsw_busy and hooking it up as appropriate
for the NS8250-class.

As it turns out, the exact equivalent of this 3rd part later on was
implemented for uftdi(4) in 9ad221a5.

While at it, explain the rational behind the deliberately missing
locking in uart_tty_busy() (also applying to the generic sc_txbusy
testing already present).

(cherry picked from commit 353e4c5a068d06b0d6dcfa9eb736ecb16e9eae45)

sys: Remove $FreeBSD$: one-line .c pattern

2023-08-23T17:43:25+00:00

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

Similar commit in current:
(cherry picked from commit 685dc743dc3b)

sys: Remove $FreeBSD$: two-line .h pattern

2023-08-23T17:43:20+00:00

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

Similar commit in current:
(cherry picked from commit 95ee2897e98f)

uart_dev_snps: Make ext_resources non-optional

2022-05-16T11:45:37+00:00

EXT_RESOURCES have been introduced in 12-CURRENT and all supported
releases have it enabled in their kernel config.

MFC after:      1 month
Differential Revision:	https://reviews.freebsd.org/D33828

(cherry picked from commit 5c00765bf2378c8ed92abe78028f203e91ddbf91)

Remove "all rights reserved" from copyright for the file that Jared McNeill

2019-12-03T21:05:33+00:00

own. He gave me permission to do this.

Update Armada 38x UART device tree binding

2018-10-10T10:34:17+00:00

Recent changes in Linux updated Marvell Armada 38x
UART compatible string. As a result the FreeBSD driver
(uart_dev_snps) does not probe. This commit fixes the
situation, however not applying any functional modification
to the driver methods.

Approved by: re (kib)
Obtained from: Semihalf

add snps IP uart support / genaralize UART

2018-08-19T21:10:21+00:00

This is an amalgam of a patch by Doug Ambrisko to
generalize uart_acpi_find_device, imp moving the
ACPI table to uart_dev_ns8250.c and advice by jhb
to work around a bug in the EPYC 3151 BIOS
(the BIOS incorrectly marks the serial ports as
disabled)

Reviewed by: imp
MFC after: 8 weeks
Differential Revision: https://reviews.freebsd.org/D16432

Now that we set the busy_detect bit in the bas to support setting it

2018-07-23T19:27:11+00:00

for the console, set our override in the bas as well.

Tested by: emaste@

uart_snps: Add early printf support

2018-05-01T13:57:08+00:00

Move the allwinner early printf support to the snps driver as it
should work with all implementation.
While here add instruction for enabling it on 64bits SoCs.

Do pass removing some write-only variables from the kernel.

2017-12-25T04:48:39+00:00

This reduces noise when kernel is compiled by newer GCC versions,
such as one used by external toolchain ports.

Reviewed by: kib, andrew(sys/arm and sys/arm64), emaste(partial), erj(partial)
Reviewed by: jhb (sys/dev/pci/* sys/kern/vfs_aio.c and sys/kern/kern_synch.c)
Differential Revision: https://reviews.freebsd.org/D10385