A major rewrite of interrupt handling for incoming mailbox processing, to split
the timing critical steps from the the deferrable steps as the sending XPU on
the CX23418 will time out and overwrite our incoming mailboxes rather quickly.
Setup a pool of work "order forms" for the irq handler to send jobs to the new
work handler routine which uses the kernel default work queue to do the
deferrable work.  Started optimizing some of the cx18-io calls as they are now
the low hanging fruit for recoving microseconds back from the timeline.
Future optimizations will get rid of mmio read retries, mmio stats logging, and
combine smaller functions in the irq path into the larger ones to save ~2 us
each.
Signed-off-by: NAndy Walls <awalls@radix.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

cx18: Throttle mmio to/from the CX23418 so boards work in older systems.  The
CX23418 couldn't reliably handle mmio at the rate at which the cx18 driver was
attempting to access the chip.  The PCI bridge arrangements and settings on
modern motherboards still allowed the CX23418 to work OK, but it didn't work
well on many older motherboards: mysterious I2C errors, firmware loading errors,
etc.  This patch adds a throttle to *all* mmio access to the CX23418.  It
defaults to a delay of 31 ns, but is adjustable by the mmio_ndelay module parm.
My HVR-1600 and Raptor PAL/SECAM card now function for analog capture on a
motherboard with an Intel 82810E Northbridge and 82801AA Southbridge.
Signed-off-by: NAndy Walls <awalls@radix.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

cx18: Create cx18_ specific wrappers for all pci mmio accessesors.  This is a
first step in instrumenting all CX23418 PCI bus IO, to debug problems with
accessing the CX23418's PCI memory mapped IO.
Signed-off-by: NAndy Walls <awalls@radix.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

cx18: Add missing lock for when the irq handler manipulates the queues.  This
was a potential source of stream queue corruption.  Also changed the name of
cx18_queue_find_buf() to cx18_queue_get_buf_irq().
Signed-off-by: NAndy Walls <awalls@radix.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

This patch contains the following possible cleanups:
- cx18-i2c.c should #include "cx18-i2c.h" for getting the prototypes of
  it's global functions
- make the following needlessly global functions static:
  - cx18-fileops.c:cx18_claim_stream()
  - cx18-fileops.c:cx18_release_stream()
  - cx18-queue.c:cx18_queue_move()
- remove the following unused functions:
  - cx18-driver.c:cx18_waitq()
  - cx18-queue.c:cx18_buf_copy_from_user()
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Reviewed-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>

Many thanks to Steve Toth from Hauppauge and Nattu Dakshinamurthy from
Conexant for their support. I am in particular thankful to Hauppauge
since without their help this driver would not exist. It should also
be noted that Steve did the work to get the DVB part up and running.
Thank you!
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NSteven Toth <stoth@hauppauge.com>
Signed-off-by: NMichael Krufky <mkrufky@linuxtv.org>
Signed-off-by: NG. Andrew Walls <awalls@radix.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>