baudrate of the device special file, and makes sure that on open(2) the
UART is programmed with the correct baudrate. This then eliminates the
need in uart_tty_param() to override the speed setting.
to check the status property in their probe routines.
Simplebus used to only instantiate its children whose status="okay"
but that was improper behavior, fixed in r261352. Now that it doesn't
check anymore and probes all its children; the children all have to
do the check because really only the children know how to properly
interpret their status property strings.
Right now all existing drivers only understand "okay" versus something-
that's-not-okay, so they all use the new ofw_bus_status_okay() helper.
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)
obsolete. This involves the following pieces:
- Remove it entirely on PowerPC, where it is not used by MD code either
- Remove all references to machine/fdt.h in non-architecture-specific code
(aside from uart_cpu_fdt.c, shared by ARM and MIPS, and so is somewhat
non-arch-specific).
- Fix code relying on header pollution from machine/fdt.h includes
- Legacy fdtbus.c (still used on x86 FDT systems) now passes resource
requests to its parent (nexus). This allows x86 FDT devices to allocate
both memory and IO requests and removes the last notionally MI use of
fdtbus_bs_tag.
- On those architectures that retain a machine/fdt.h, unused bits like
FDT_MAP_IRQ and FDT_INTR_MAX have been removed.
static device mappings.
This SoC relied heavily on the fact that all devices were static-mapped
at a fixed address, and it (rather bogusly) used bus_space read and write
calls passing hard-coded virtual addresses instead of proper bus handles,
relying on the fact that the virtual addresses of the mappings were known
at compile time, and relying on the implementation details of arm
bus_space never changing. All such usage was replaced with calls to
bus_space_map() to obtain a proper bus handle for the read/write calls.
This required adjusting some of the #define values that map out hardware
registers, and some of them were renamed in the process to make it clear
which were defining absolute physical addresses and which were defining
offsets. (The ones that just define offsets don't appear to be referenced
and probably serve no value other than perhaps documentation.)
clients. Mask RX interrupts while grabbed on the atmel serial
driver. This UART interrupts every character. When interrupts are
enabled at the mountroot> prompt, this means the ISR eats the
characters. Rather than try to create a cooperative buffering system
for the low level kernel console, instead just mask out the ISR. For
NS8250 and decsendents this isn't needed, since interrupts only happen
after 14 or more characters (depending on the fifo settings). Plumb
such that these are optional so there's no change in behavior for all
the other UART clients. ddb worked on this platform because all
interrupts were disabled while it was running, so this problem wasn't
noticed. The mountroot> issue has been around for a very very long
time.
MFC after: 3 days
strings as uart_bus_fdt's probe().
The bus code uses ofw_bus_search_compatible() and that's not an option in
cpu (console) code -- it runs way before the ofw routines are usable. So
the console probe has its own loop to search the table, but now at least
there's only one table to be maintained when new devices are added.
/chosen, following the list of allowed console properties in ePAPR. Also
do not require that stdin be defined and equal to stdout: stdin is
nonstandard (for ePAPR) and console in an unexpected place is after all
better than no console.
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)
is not giving us a 100% success rate. Bump the delay to 200ms as
that seems to do the trick.
Note that during testing the delay was added to uart_bus_attach()
in uart_core.c. While having the delay in a different place can
change the behaviour, it was not expected. Having to bump the
delay with another 50ms could therefore be an indication that
the problem can not be solved with delays.
Reported by: kevlo@
Tested by: kevlo@
calls ns8250_bus_ipend() almost immediately after ns8250_bus_attach().
As it appears, a line break condition is being signalled for almost
all received characters due to this. A delay of 150ms seems enough
to allow the H/W to settle and to avoid the problem.
More analysis is needed, but for now a regression has been addressed.
Reported by: kevlo@
Tested by: kevlo@
The TI uart hardware is ns16550-compatible, except that before it can
be used the clocks and power have to be enabled and a non-standard
mode control register has to be set to put the device in uart mode
(as opposed to irDa or other serial protocols). This adds the extra
code in an extension to the standard ns8250 probe routine, and the
rest of the driver is just the standard ns8250 code.
This makes it easier to implement new drivers which are "mostly ns8250"
but with some small difference such as needing to enable clocks or poke
a non-standard register at probe or attach time.
device compatible with multiple drivers matches the more specific driver
first and doesn't overwrite it later with the more generic. Move the
generic ns16550 to the end of the list.
we call device-specific probe functions, which can (and typically will)
set the device description based on low-level device probe information.
In the end we never actually used the device description that we so
carefully maintained in the PCI match table. By setting the device
description after we call uart_probe(), we'll print the more user-
friendly description by default.
H/W not de-asserting the interrupt at all. On x86, and because of the
following conditions, this results in a hard hang with interrupts disabled:
1. The uart(4) driver uses a spin lock to protect against concurrent
access to the H/W. Spin locks disable and restore interrupts.
2. Restoring the interrupt on x86 always writes the flags register. Even
if we're restoring the interrupt from disabled to disabled.
3. The x86 CPU has a short window in which interrupts are enabled when the
flags register is written.
4. The uart(4) driver registers a fast interrupt by default.
To catch this case, we first try to clear any pending H/W interrupts and in
particular, before setting up the interrupt. This makes sure the interrupt
is masked on the PIC. The interrupt handler now has a limit set on the
number of iterations it'll go through to clear interrupt conditions. If the
limit is hit, the handler will return FILTER_SCHEDULE_THREAD. The attach
function will check for this return code and avoid setting up the interrupt
and foce polling in that case.
Obtained from: Juniper Networks, Inc.
1. Common headers for fdt.h and ofw_machdep.h under x86/include
with indirections under i386/include and amd64/include.
2. New modinfo for loader provided FDT blob.
3. Common x86_init_fdt() called from hammer_time() on amd64 and
init386() on i386.
4. Split-off FDT specific low-level console functions from FDT
bus methods for the uart(4) driver. The low-level console
logic has been moved to uart_cpu_fdt.c and is used for arm,
mips & powerpc only. The FDT bus methods are shared across
all architectures.
5. Add dev/fdt/fdt_x86.c to hold the fdt_fixup_table[] and the
fdt_pic_table[] arrays. Both are empty right now.
FDT addresses are I/O ports on x86. Since the core FDT code does
not handle different address spaces, adding support for both I/O
ports and memory addresses requires some thought and discussion.
It may be better to use a compile-time option that controls this.
Obtained from: Juniper Networks, Inc.
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().
to the same thing) by allocating the uart(4) rx buffer based on the
device's rxfifosz rather than using a hard-coded size of 384 bytes.
The historical 384 byte size is 3 times the largest hard-coded fifo
size in the tree, so use that ratio as a guide and allocate the buffer
as three times rxfifosz, but never smaller than the historical size.
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@
x86 buses
Otherwise the uart hardware could be in such a state after the resume
where IER is cleared and thus no interrupts are generated.
This behavior is observed and tested with QEMU, so I am comitting this
change to help with my debugging.
There has been no feedback from users of serial ports on real hardware.
MFC after: 20 days
bug in old versions of QEMU (and Xen, and other places using QEMU code).
On those buggy emulated UARTs, the "TX idle" interrupt gets lost; with
this workaround, we spinwait for the TX to happen and then send ourselves
the interrupt. It's ugly but it works, while minimizing the impact on
the code for the !broken_txfifo case.
MFC after: 2 weeks
