This patch fixes the poll routine for the natsemi driver so that if the
driver detects an RX state machine lockup then no interrupts will be
lost while the driver recovers from that.

Signed-Off-By: Mark Brown <broonie@sirena.org.uk>

Signed-off-by: Jeff Garzik <jeff@garzik.org>

The interrupt status register for the natsemi chips is clear on read and
was read unconditionally from both the interrupt and from the NAPI poll
routine, meaning that if the interrupt service routine was called (for
example, due to a shared interrupt) while a NAPI poll was scheduled
interrupts could be missed.  This patch fixes that by ensuring that the
interrupt status register is only read by the interrupt handler when
interrupts are enabled from the chip.

It also reverts a workaround for this problem from the netpoll hook and
improves the trace for interrupt events.

Thanks to Sergei Shtylyov <sshtylyov@ru.mvista.com> for spotting the
issue, Mark Huth <mhuth@mvista.com> for a simpler method and Simon
Blake <simon@citylink.co.nz> for testing resources.

Signed-Off-By: Mark Brown <broonie@sirena.org.uk>

Signed-off-by: Jeff Garzik <jeff@garzik.org>

The natsemi drivers include functions for enabling and disabling
interrupts from the chip but these are not used in all code paths.  This
patch changes the code paths that touch the interrupt enable register to
use the functions.  In all cases this adds an extra PCI read to post the
operation but since none of these are in fast paths this shouldn't be
too much of a problem.

Signed-Off-By: Mark Brown <broonie@sirena.org.uk>

Signed-off-by: Jeff Garzik <jeff@garzik.org>

Fix two issues in this driver's netpoll path: one usual, with spin_unlock_irq()
enabling interrupts which nobody asks it to do (that has been fixed recently in
a number of drivers) and one unusual, with poll_controller() method possibly
causing loss of interrupts due to the interrupt status register being cleared
by a simple read and the interrpupt handler simply storing it, not accumulating.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

Bob Tracy <rct@gherkin.frus.com> reported that the addition of support
for Aculab E1/T1 cPCI carrier cards broke detection of vanilla natsemi
cards.  This patch fixes that: the problem is that the driver-specific
ta in the PCI device table is an index into a second table and this
had not been updated for the vanilla cards.

This patch fixes the problem minimally.

Signed-Off-By: Mark Brown <broonie@sirena.org.uk>

Signed-off-by: Jeff Garzik <jeff@garzik.org>

Aculab E1/T1 PMXc cPCI carrier card cards present a natsemi on the cPCI
bus with an oversized EEPROM using a direct MII<->MII connection with no
PHY.  This patch adds a new device table entry supporting these cards.

Signed-Off-By: Mark Brown <broonie@sirena.org.uk>

Signed-off-by: Jeff Garzik <jeff@garzik.org>

This patch provides code paths which allow the natsemi driver to use the
external MII port on the chip but ignore any PHYs that may be attached to it.
The link state will be left as it was when the driver started and can be
configured via ethtool.  Any PHYs that are present can be accessed via the MII
ioctl()s.

This is useful for systems where the device is connected without a PHY
or where either information or actions outside the scope of the driver
are required in order to use the PHYs.

Signed-Off-By: Mark Brown <broonie@sirena.org.uk>

Signed-off-by: Jeff Garzik <jeff@garzik.org>

Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

Signed-off-by: Jeff Garzik <jeff@garzik.org>

Signed-off-by: Jeff Garzik <jeff@garzik.org>