Add run time control for receive DMA buffer fill level to allow
application to control receive latency when using stream oriented serial
protocols that pass receive data to application only after a DMA buffer
fills. This was previously a compile time option, but run time control is
needed when application changes data rate (and latency requirements) or
uses different data rates on different ports.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Leave the transmitter in reset state after configuration so that transmit
signal is held at mark until transmitter is explicitly enabled by
application, otherwise transmitter sends idle pattern.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Improve the accuracy of TIOCOUTQ value as implemented in chars_in_buffer()
method by walking and counting tx DMA buffers, reading controller tx FIFO
level and accounting for controller tx shift register. The greatly
improves application control of transmit latency at lower data rates.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add control of hardware serial bit order between LSB first
(default/standard) and MSB first.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Improve write method by allowing multiple HDLC frames to be loaded into tx
DMA buffer ring for continuous frame transmission. This simplifies the
transmit code by using the common procedures for all serial protocols.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make n_hdlc line discipline honor the O_NONBLOCK file flag on write.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With SMP kernels _irqsave spinlock disables only local interrupts, while
the shared serial interrupt could be assigned to the CPU that is not
currently starting up the serial port.
This might cause issues because serial8250_startup() routine issues
IRQ-triggering operations before registering the port in the IRQ chain
(though, this is fine to do and done explicitly because we don't want to
process any interrupts on the port startup).
With RT kernels and preemptable hardirqs, _irqsave spinlock does not
disable local hardirqs, and the bug could be reproduced much easily:
$ cat /dev/ttyS0 &
$ cat /dev/ttyS1
irq 42: nobody cared (try booting with the "irqpoll" option)
Call Trace:
[C0475EB0] [C0008A98] show_stack+0x4c/0x1ac (unreliable)
[C0475EF0] [C004BBD4] __report_bad_irq+0x34/0xb8
[C0475F10] [C004BD38] note_interrupt+0xe0/0x308
[C0475F50] [C004B09C] thread_simple_irq+0xdc/0x104
[C0475F70] [C004B3FC] do_irqd+0x338/0x3c8
[C0475FC0] [C00398E0] kthread+0xf8/0x100
[C0475FF0] [C0011FE0] original_kernel_thread+0x44/0x60
handlers:
[<c02112c4>] (serial8250_interrupt+0x0/0x138)
Disabling IRQ #42
After this, all serial ports on the given IRQ are non-functional.
To fix the issue we should explicitly disable shared IRQ before
issuing any IRQ-triggering operations.
I also changed spin_lock_irqsave to the ordinary spin_lock, since it
seems to be safe: chain does not contain new port (yet), thus nobody
will interfere us from the ISRs.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the epca driver to call epca_setup() if digiepca=xxx is included on the
command line and the epca driver is built in.
epca_setup() used to be called from init/main.c in 2.2 kernels, but somewhere
along the way that call was removed but not replaced.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add support for CP-102UF moxa card (update to 1.12 original driver) and
increment this driver version.
(Somewhat reworked by alan@redhat.com to merge in with other patches)
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the hardware break support on the specialix driver
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the Stallion driver's putchar() and break_ctl() ops and iStallion's
putchar() to return values.
Is it actually possible for putchar() or break_ctl() to be called with tty ==
NULL or can the check be discarded?
Should stl_write() be returning 0 if tty->driver_data is NULL or tx.buf is
NULL? Is this even possible?
I've made Stallion's functions return -EINVAL as stli_breakctl() if the checks
fail.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert the driver to use the added hardware break support
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some hardware needs to do break handling itself and may have partial
support only. Make break_ctl return an error code. Add a tty driver flag
so you can indicate driver hardware side break support.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nobody seems to use these drivers anyway so if they want them they can
fix them up. I don't have the needed info to add break_ctl support to them.
Send patches if you don't like it.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ioctls it talks about are midlayer provided.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Go through the inlines and other oddments that are iffy. Remove various bits
of dead code and bogus debug. Turn the crtsdts compile time option into a
runtime switch.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Preparation for doing some real work on the driver. Do this first so we can
easily identify if the cleanups accidentally broke something
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The edgeport reports negative error codes to functions that do not
expect them. This can cause ports to jam forever
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
