cx18: Reduce number of mmio read retries to improve performance. Experiments
have shown 2 things: read retries never improve the result of a suspect mmio
read from the CX23418 (the result stays all 0xff's), and that most of the
suspected read failures are actually proper reads of values that should be
all 0xff's. This change reduces the number of read retries and keeps the
count separate from write retries.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
cx18: Fix write retries for registers that always change - part 2.
Some registers, especially interrupt related ones, will never read
back the value just written. Modified interrupt register readback
checks to make sure the intended effect was achieved.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
cx18: Add __iomem address space qualifier to cx18_log_*_retries() addr
argument to clean up sparse build warnings.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
cx18: Add default behavior of checking and retrying PCI MMIO accesses.
The concept of checking and retrying PCI MMIO accesses for better reliability
in older motherboards was suggested by Steve Toth <stoth@linuxtv.org>. This
change implements MMIO retries and the retry_mmio module parameter that is
enabled by default. Limited experiments have shown this is more reliable than
the mmio_ndelay parameter. mmio_ndelay has insignificant effect with retries
enabled.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro 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: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro 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: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Andy Walls