uart: Use device_set_descf()

No functional change intended.

MFC after: 1 week

(cherry picked from commit 66d2d42a1f26a6ef868d7d46f87d6fad0bc099aa)

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

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

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

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sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error

sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

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Add support for the uart classes to set their default register shift value.
This is needed with the pl011 driver. Before this change it would default
to a shift of 0, however the hardware places the

Add support for the uart classes to set their default register shift value.
This is needed with the pl011 driver. Before this change it would default
to a shift of 0, however the hardware places the registers at 4-byte
addresses meaning the value should be 2.

This patch fixes this for the pl011 when configured using the fdt. The
other drivers have a default value of 0 to keep this a no-op.

MFC after: 1 week

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Introduce grab and ungrab upcalls. When the kernel desires to grab the
console, it calls the grab functions. These functions should turn off
the RX interrupts, and any others that interfere. This mak

Introduce grab and ungrab upcalls. When the kernel desires to grab the
console, it calls the grab functions. These functions should turn off
the RX interrupts, and any others that interfere. This makes mountroot
prompt work again. If there's more generalized need other than
prompting, many of these routines should be expanded to do those new
things.

Should have been part of r260889, but waasn't due to command line typo.

Reviewed by: bde (with reservations)

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Fix low-level uart drivers that set their fifo sizes in the softc too late.

uart(4) allocates send and receiver buffers in attach() before it calls
the low-level driver's attach routine. Many low-l

Fix low-level uart drivers that set their fifo sizes in the softc too late.

uart(4) allocates send and receiver buffers in attach() before it calls
the low-level driver's attach routine. Many low-level drivers set the
fifo sizes in their attach routine, which is too late. Other drivers set
them in the probe() routine, so that they're available when uart(4)
allocates buffers. This fixes the ones that were setting the values too
late by moving the code to probe().

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Don't expose the uart_ops structure directly, but instead have
it obtained through the uart_class structure. This allows us
to declare the uart_class structure as weak and as such allows
us to refere

Don't expose the uart_ops structure directly, but instead have
it obtained through the uart_class structure. This allows us
to declare the uart_class structure as weak and as such allows
us to reference it even when it's not compiled-in.
It also allows is to get the uart_ops structure by name, which
makes it possible to implement the dt tag handling in uart_getenv().
The side-effect of all this is that we're using the uart_class
structure more consistently which means that we now also have
access to the size of the bus space block needed by the hardware
when we map the bus space, eliminating any hardcoding.

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- Add a uart_rxready() and corresponding device-specific implementations
that can be used to check whether receive data is ready, i.e. whether
the subsequent call of uart_poll() should return a c

- Add a uart_rxready() and corresponding device-specific implementations
that can be used to check whether receive data is ready, i.e. whether
the subsequent call of uart_poll() should return a char, and unlike
uart_poll() doesn't actually receive data.
- Remove the device-specific implementations of uart_poll() and implement
uart_poll() in terms of uart_getc() and the newly added uart_rxready()
in order to minimize code duplication.
- In sunkbd(4) take advantage of uart_rxready() and use it to implement
the polled mode part of sunkbd_check() so we don't need to buffer a
potentially read char in the softc.
- Fix some mis-indentation in sunkbd_read_char().

Discussed with: marcel

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On PowerPC the clock for the BRG comes from RTxC, not PCLK. Add a
quick hack to deal with this. We may need to formalize this better
and have this information come from the bus attachments.

Implement UART_IOCTL_BAUD for the Z8530. This allows a serial console
on PowerPC use the current setting of the hardware and not second
guess what the OFW does on various machines.

o A divisor of 0 is perfectly valid. Reserve -1 for an invalid
divisor. This allows us to set the line speed to the maximum
of 1/4 of the device clock.
o Disable the baudrate generator before

o A divisor of 0 is perfectly valid. Reserve -1 for an invalid
divisor. This allows us to set the line speed to the maximum
of 1/4 of the device clock.
o Disable the baudrate generator before programming the line
settings, including baudrate, and enable it afterwards.

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In z8530_divisor() return 0 if the calculated divisor is less than 0.
This happens when the baudrate is too high for the given RCLK.

Don't hold the hardware mutex across getc(). It can wait indefinitely
for a character to be received. Instead let getc() do any necesary
locking.

Add support for scc(4).

Replace our local UART_SIGMASK_* with the global SER_MASK_*.

MFp4:
Stop using our local UART_IPEND_* and instead use the global SER_INT_*
as defined in <sys/serial.h>.

Make the Z8530 more reliable as low-level console by making use of the
fact that access to RR0 does not need a prior write to the register
index because the index always reverts to 0 after the indexe

Make the Z8530 more reliable as low-level console by making use of the
fact that access to RR0 does not need a prior write to the register
index because the index always reverts to 0 after the indexed register
has been accessed.

Typically when a RR or WR is to accessed, one programs the index (which
is a write to the control register), followed by a read or write to the
actual indexed register (a read pr write to the same control register).
When this non-atomic sequence is interrupted after having written the
index and low-level console I/O is done in that situation, the write to
program the index will actually write to the indexed register and nuke
state. This almost always yields a wedge.

By not programming the index register and instead just reading from RR0,
the worst case scenario is non-fatal. For if we don't actually read from
RR0 but some other register we get an invalid status, which may lead us
to conclude that the transit data register is empty when it's not or that
the receive data register contains data when it doesn't. Hence, we may
lose an output character or get a sporadic input character, but given
the situation this is a non-issue.

Full serialization is not possible due to the fact that this code needs
to work from DDB and before mutex initialization has happened.

In collaboration with: kris@, marius@
Tested by: kris@
MFC after: 1 day
X-MFC: 5.4-RELEASE candidate

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o Fix the various interrupt related problems caused by reverse
engineering the pending interrupt sources from the current
state of the controller. For channel A we can always read the
inter

o Fix the various interrupt related problems caused by reverse
engineering the pending interrupt sources from the current
state of the controller. For channel A we can always read the
interrupt pending register (RR3). For channel B we can read
the interrupt vector register (RR2) because it contains the
modified vector and thus includes the interrupt source.
Since we currently need puc(4) for the Z8530, we know that
the interrupt handler for both channels will be called and
thus that RR3 will always be read at least once, even if ch A
has no pending interrupt.
NOTE: The modified interrupt vector has no value that represent
a lack of pending interrupt for channel B. That is, the
value read when no interrupts are pending is the same as the
value for the special receive condition. Fortunately, we don't
actually have to depend on that interrupt source. This does
mean that we need to properly handle the overflow condition,
when we read received character from the chip.
o The DSR signal is represented by the SYNC bit in the external
status register (RR0). We now properly track DSR.
o It's save to enable the external/status interrupt source. We
now get interrupts when line signals (DSR, DCD or CTS) change.

Problems fixes:
o interrupt storms.
o blocked open(2).
o lack of (hardware) flow control.
o unable to report DSR.

MFC after: 5 days

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Start each of the license/copyright comments with /*-, minor shuffle of lines

Include the header with the register definitions from sys/dev/ic. They
are shared now.

Use the new serial port definitions for modemsignals.

Fix hangs caused by z8530_bus_ipend() returning UART_IPEND_TXIDLE
not as a pending interrupt status, but as a matter of status quo.
Consequently, when there's no data to be transmitted the condition

Fix hangs caused by z8530_bus_ipend() returning UART_IPEND_TXIDLE
not as a pending interrupt status, but as a matter of status quo.
Consequently, when there's no data to be transmitted the condition
is not cleared and uart_intr() is stuck in an infinite loop trying
to clear the UART_IPEND_TXIDLE status.
The z8530_bus_ipend() function is changed to return idle only once
after having sent any data.

The root cause for this problem is that we cannot use the interrupt
status bits of the SCC itself. The register that holds the interrupt
status can only be accessed by channel A and holds the status for
both channels. Using the interrupt status register would complicate
the driver because we need to synchronize access to the SCC between
the channels.

Elementary testing: marius

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Revert the introduction of iobase in struct uart_bas. Both the SAB82532
and the Z8530 drivers used the I/O address as a quick and dirty way to
determine which channel they operated on, but formalizin

Revert the introduction of iobase in struct uart_bas. Both the SAB82532
and the Z8530 drivers used the I/O address as a quick and dirty way to
determine which channel they operated on, but formalizing this by
introducing iobase is not a solution. How for example would a driver
know which channel it controls for a multi-channel UART that only has a
single I/O range?

Instead, add an explicit field, called chan, to struct uart_bas that
holds the channel within a device, or 0 otherwise. The chan field is
initialized both by the system device probing (i.e. a system console)
or it is passed down to uart_bus_probe() by any of the bus front-ends.
As such, it impacts all platforms and bus drivers and makes it a rather
large commit.

Remove the use of iobase in uart_cpu_eqres() for pc98. It is expected
that platforms have the capability to compare tag and handle pairs for
equality; as to determine whether two pairs access the same device or
not. The use of iobase for pc98 makes it impossible to formalize this
and turn it into a real newbus function later. This commit reverts
uart_cpu_eqres() for pc98 to an unimplemented function. It has to be
reimplemented using only the tag and handle fields in struct uart_bas.

Rewrite the SAB82532 and Z8530 drivers to use the chan field in struct
uart_bas. Remove the IS_CHANNEL_A and IS_CHANNEL_B macros. We don't
need to abstract anything anymore.

Discussed with: nyan
Tested on: i386, ia64, sparc64

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- Keep the base address in struct uart_bas for sab82532 and z8530 modules.
- Remove buggy uart_cpu_busaddr() function.