This patch is based on the DMA-patch by Chip Coldwell for the AT91/AT32 serial
USARTS, with some tweaks to make it apply neatly on top of the other patches
in this series.
The RX and TX code has been moved to a tasklet and reworked a bit. Instead of
depending on the ENDRX and TIMEOUT bits in CSR, we simply grab as much data as
we can from the DMA buffers. I think this closes a race where the ENDRX bit
is set after we read CSR but before we read RPR, although I haven't confirmed
this.
Similarly, the two TX handlers (ENDTX and TXBUFE) have been combined into one.
Since the current code only uses a single TX buffer, there's no point in
handling those interrupts separately.
This also fixes a DMA sync bug in the original patch.
[linux@bohmer.net: rebased onto irq-splitup patch]
[hskinnemoen@atmel.com: moved to tasklet, fixed dma bug, misc cleanups]
[hskinnemoen@atmel.com: atmel_serial dma: Misc fixes and cleanups]
Signed-off-by: Remy Bohmer <linux@bohmer.net>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andrew Victor <linux@maxim.org.za>
Tested-by: Marc Pignat <marc.pignat@hevs.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Split up the interrupt handler of the serial port into a interrupt top-half
and a tasklet.
The goal is to get the interrupt top-half as short as possible to minimize
latencies on interrupts. But the old code also does some calls in the
interrupt handler that are not allowed on preempt-RT in IRQF_NODELAY context.
This handler is executed in this context because of the interrupt sharing with
the timer interrupt. The timer interrupt on Preempt-RT runs in IRQF_NODELAY
context.
The tasklet takes care of handling control status changes, pushing incoming
characters to the tty layer, handling break and other errors. It also handles
pushing TX data into the data register.
Reading the complete receive queue is still done in the top-half because we
never want to miss any incoming character.
[hskinnemoen@atmel.com: misc cleanups and simplifications]
Signed-off-by: Remy Bohmer <linux@bohmer.net>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andrew Victor <linux@maxim.org.za>
Tested-by: Marc Pignat <marc.pignat@hevs.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When an error happens in probe(), the clocks should be disabled, but
only if the port isn't already used as a console.
In remove(), the port struct shouldn't be freed because it's defined
statically.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andrew Victor <linux@maxim.org.za>
Tested-by: Marc Pignat <marc.pignat@hevs.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace two instances of barrier() with cpu_relax() since that's the right
thing to do when busy-waiting. This does not actually change anything since
cpu_relax() is defined as barrier() on both ARM and AVR32.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Tested-by: Marc Pignat <marc.pignat@hevs.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a set of changes to implement proper resource management in the
driver, including iomem space reservation and operating on physical
addresses ioremap()ped appropriately using accessory functions rather than
unportable direct assignments.
Some adjustments to code are made to reflect the architecture of the
interface, which is a centrally controlled multiport (or, as referred to
from DEC documentation, a serial line multiplexer, going up to 8 lines
originally) rather than a bundle of separate ports.
Types are changed, where applicable, to specify the width of hardware
registers explicitly. The interrupt handler is now managed in the
->startup() and ->shutdown() calls for consistency with other drivers and
also in preparation to handle the handover from the initial firmware-based
console gracefully.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace all casts from "struct uart_port *" to "struct dz_port *" with a
construct based on container_of(). This makes the conversion work
irrespective of where the former struct is located within the latter.
By popular request I have implemented it as an inline function rather than
a macro this time.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A set of changes to the way termios settings are propagated to the serial
port hardware. The DZ11 only supports a selection of fixed baud settings,
so some requests may not be fulfilled. Keep the old setting in such a case
and failing that resort to 9600bps. Also add a missing update of the
transmit timeout. And remove the explicit encoding of the line selected
from writes to the Line Parameters Register as it has been preencoded by
the ->set_termios() call already. Finally, remove a duplicate macro for
the Receiver Enable bit.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Handle the read and ignore status masks correctly. Handle the BREAK condition
as expected: a framing error with a null character is a BREAK, any other
framing error is a framing error indeed.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ->start_tx(), ->stop_tx() and ->stop_rx() backends are called with the
port's lock already taken. Remove locking from within them and wrap around
calls as necessary.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
