When using DW UART with BUSY detection it is necessary to wait
until all serial transfers are finished before manipulating the
line control. LCR will not be affected when UART is busy.
In addition, if Divisor Latch Access Bit is being set in order to
modify UART divisors:
1. We will get BUSY interrupt if interrupts are enabled.
2. Because LCR will not be affected the THR and (even worse) IER
contents will be corrupted. This will lead to console hang.
Approved by: cognet (mentor)
A10 uart is derived from Synopsys DesignWare uart and requires
to read Uart Status Register when IIR_BUSY has detected.
Also this change includes FDT check, where it checks device
specific properties defined in dts and sets the busy_detect variable.
broken_txfifo is also needed to be set in order to make it work for
A10 uart case.
Reviewed by: marcel@
Approved by: gonzo@
The QUICC engine is found on various Freescale parts including MPC85xx, and
provides multiple generic time-division serial channel resources, which are in
turn muxed/demuxed by the Serial Communications Controller (SCC).
Along with core QUICC/SCC functionality a uart(4)-compliant device driver is
provided which allows for serial ports over QUICC/SCC.
Approved by: cognet (mentor)
Obtained from: Juniper
MFp4: e500
Use it to reset controller and to select data rate. According to Intel
80277AA datasheet, software reset behaves the same as DOR reset except
that it is self clearing. National Semiconductor PC8477B datasheet says
the same. As a side effect, we no longer use Configuration Control
Register (CCR) at 0x3f7 for these controllers, which is often missing
in modern hardware.
- Rename REG_DL to REG_DLL and REG_DLH.
- Always treat DLL and DLH as two separate 8-bit registers instead of one
16-bit register.
Additionally, remove the probe for the high 4 bits of IER being 0 and don't
assume we can always read/write 0 to/from those bits.
These changes allow uart(4) to drive the UARTs on the Intel XScale PXA255.
Reviewed by: marcel
i8253reg.h, and add some defines to control a speaker.
- Move PPI related defines from i386/isa/spkr.c into ppireg.h and use them.
- Move IO_{PPI,TIMER} defines into ppireg.h and timerreg.h respectively.
- Use isa/isareg.h rather than <arch>/isa/isa.h.
Tested on: i386, pc98
uses the i8237 without trying to emulate the PC architecture move
the register definitions for the i8237 chip into the central include
file for the chip, except for the PC98 case which is magic.
Add new isa_dmatc() function which tells us as cheaply as possible
if the terminal count has been reached for a given channel.
not used and aliases for other defines.
o Add REG_DATA as an alias for com_data. Likewise for other register
defines.
o Add LCR_SBREAK and make CFCR_SBREAK an alias for it. Likewise for
the other LCR register bits that are known with the CFCR prefix.
o Add MCR_IE and make MCR_IENABLE an alias for it.
o Add LSR_TEMT and make LSR_TSRE an alias for it.
o Add LSR_THRE and make LSR_TXRDY as alias for it.
o Add FCR_ENABLE and make FIFO_ENABLE as alias for it. Likewise for
the other FCR register bits that are known with the FIFO prefix.
o Add EFR_CTS and make EFR_AUTOCTS an alias for it.
o Add EFR_RTS and make EFR_AUTORTS an alias for it.
This is a first step in cleaning up the definitions in this file.
additions to sys/amd64/isa/icu.h from PIIX4 and other datasheets. I
tweaked a few comments based on the NetBSD header of the same name when I
merged the constants to sys/i386/isa/icu.h, but the vast majority of this
file was created independently by Peter and not taken from any existing
files.
Submitted by: peter
and some of their bits (i.e., fifo trigger levels, frequency multipliers
and divisors, and bits to select the registers for these). This
attempts to completely describe the 16950's complicated register selects
for 16950-specific registers only.
the description of the data latch registers (they were described as
readonly).
Added some better and worse aliases for standard registers, mostly taken
from the 16950 data sheet. Define deprecated aliases in terms of the
preferred one.
Don't define com_efr in terms of com_fifo. It is unrelated (in a
different bank).
Merged comments to match (put them at the right of the #defines instead
of duplicating them).
Sorted the resulting sections on UART type and register bank. Added a
comment for each bank.
to ns16550.h. The organization of these files was sort of backwards.
The bits in the registers have no driver or bus dependencies but they
but the offsets of the registers in bus space are very bus-dependent.
However, it does no harm to keep the definitions of the register offsets
in ns16550.h provided they are thought of as internal ns*50 offsets.
It improves on sio(4) in the following areas:
o Fully newbusified to allow for memory mapped I/O. This is a must
for ia64 and sparc64,
o Machine dependent code to take full advantage of machine and firm-
ware specific ways to define serial consoles and/or debug ports.
o Hardware abstraction layer to allow the driver to be used with
various UARTs, such as the well-known ns8250 family of UARTs, the
Siemens sab82532 or the Zilog Z8530. This is especially important
for pc98 and sparc64 where it's common to have different UARTs,
o The notion of system devices to unkludge low-level consoles and
remote gdb ports and provides the mechanics necessary to support
the keyboard on sparc64 (which is UART based).
o The notion of a kernel interface so that a UART can be tied to
something other than the well-known TTY interface. This is needed
on sparc64 to present the user with a device and ioctl handling
suitable for a keyboard, but also allows us to cleanly hide an
UART when used as a debug port.
Following is a list of features and bugs/flaws specific to the ns8250
family of UARTs as compared to their support in sio(4):
o The uart(4) driver determines the FIFO size and automaticly takes
advantages of larger FIFOs and/or additional features. Note that
since I don't have sufficient access to 16[679]5x UARTs, hardware
flow control has not been enabled. This is almost trivial to do,
provided one can test. The downside of this is that broken UARTs
are more likely to not work correctly with uart(4). The need for
tunables or knobs may be large enough to warrant their creation.
o The uart(4) driver does not share the same bumpy history as sio(4)
and will therefore not provide the necessary hooks, tweaks, quirks
or work-arounds to deal with once common hardware. To that extend,
uart(4) supports a subset of the UARTs that sio(4) supports. The
question before us is whether the subset is sufficient for current
hardware.
o There is no support for multiport UARTs in uart(4). The decision
behind this is that uart(4) deals with one EIA RS232-C interface.
Packaging of multiple interfaces in a single chip or on a single
expansion board is beyond the scope of uart(4) and is now mostly
left for puc(4) to deal with. Lack of hardware made it impossible
to actually implement such a dependency other than is present for
the dual channel SAB82532 and Z8350 SCCs.
The current list of missing features is:
o No configuration capabilities. A set of tunables and sysctls is
being worked out. There are likely not going to be any or much
compile-time knobs. Such configuration does not fit well with
current hardware.
o No support for the PPS API. This is partly dependent on the
ability to configure uart(4) and partly dependent on having
sufficient information to implement it properly.
As usual, the manpage is present but lacks the attention the
software has gotten.
hardware is interrupt-driven to a fault and sending a BREAK requires
mode switching. Always running in the BREAK-capable mode as in PR 8318
would double the overhead for sending \0's.
Reminded by: PR 8318
number of dma overruns/underruns for systems under heavy dma load.
As a side effect, broken enhanced floppy controllers that sometimes
don't detect dma overruns/underruns will give less errors.
Reviewed by: j@uriah.heep.sax.de (J Wunsch)
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
(1) Add PC98 support to apm_bios.h and ns16550.h, remove pc98/pc98/ic
(2) Move PC98 specific code out of cpufunc.h (to pc98.h)
(3) Let the boot subtrees look more alike
Submitted by: The FreeBSD(98) Development Team
<freebsd98-hackers@jp.freebsd.org>
1. Create 2 x 8k transmit buffer blocks in place of the 16k block previously.
With this change the speed as tested with ttcp on a 2Mbit link went up
from 206kbyte/s to 236kbyte/s.
2. Change the rest of the functions to also have the definition of the
return value on a sepperate line.
3. Remove some unused variables.
4. Add code to recover from DMA underruns.
5. Reorder ar_get_packets() to handle errors better.
6. Only allocate a mbuf cluster if the data is more than the mbuf.
(and in a second diff in addition to the above)
7. Stops the occasional DMA underruns that occurred when 2 channels
are running at 2Mbit/s.
Submitted by: John Hay <jhay@mikom.csir.co.za>
