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  1. 10 7月, 2007 4 次提交
  3. 15 5月, 2007 1 次提交
    • A
      IB/ipath: Shadow the gpio_mask register · 8f140b40
      由 Arthur Jones 提交于 
      Once upon a time, GPIO interrupts were rare.  But then a chip bug in
the waldo series forced the use of a GPIO interrupt to signal packet
reception.  This greatly increased the frequency of GPIO interrupts
which have the gpio_mask bits set on the waldo chips.  Other bits in
the gpio_status register are used for I2C clock and data lines, these
bits are usually on.  An "unlikely" annotation leftover from the old
days was improperly applied to these bits, and an unnecessary chip
mmio read was being accessed in the interrupt fast path on waldo.

Remove the stagnant unlikely annotation in the interrupt handler and
keep a shadow copy of the gpio_mask register to avoid the slow mmio
read when testing for interruptable GPIO bits.
Signed-off-by: NArthur Jones <arthur.jones@qlogic.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>
      8f140b40
  5. 19 4月, 2007 3 次提交
  7. 13 12月, 2006 1 次提交
  9. 09 11月, 2006 1 次提交
  11. 05 10月, 2006 1 次提交
    • D
      IRQ: Maintain regs pointer globally rather than passing to IRQ handlers · 7d12e780
      由 David Howells 提交于 
      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: NDavid Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
      7d12e780
  13. 29 9月, 2006 5 次提交
  15. 23 9月, 2006 3 次提交
  17. 02 7月, 2006 8 次提交
  19. 01 7月, 2006 1 次提交
  21. 02 5月, 2006 2 次提交
  23. 20 4月, 2006 1 次提交
  25. 01 4月, 2006 1 次提交
    • B
      IB/ipath: misc driver support code · 108ecf0d
      由 Bryan O'Sullivan 提交于 
      EEPROM support, interrupt handling, statistics gathering, and write
combining management for x86_64.

A note regarding i2c: The Atmel EEPROM hardware we use looks like an
i2c device electrically, but is not i2c compliant at all from a
functional perspective.  We tried using the kernel's i2c support to
talk to it, but failed.

Normal i2c devices have a single 7-bit or 10-bit i2c address that they
respond to.  Valid 7-bit addresses range from 0x03 to 0x77.  Addresses
0x00 to 0x02 and 0x78 to 0x7F are special reserved addresses
(e.g. 0x00 is the "general call" address.)  The Atmel device, on the
other hand, responds to ALL addresses.  It's designed to be the only
device on a given i2c bus.  A given i2c device address corresponds to
the memory address within the i2c device itself.

At least one reason why the linux core i2c stuff won't work for this
is that it prohibits access to reserved addresses like 0x00, which are
really valid addresses on the Atmel devices.
Signed-off-by: NBryan O'Sullivan <bos@pathscale.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>
      108ecf0d