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  1. 22 11月, 2008 2 次提交
    • P
      i2c-omap: Close suspected race between omap_i2c_idle() and omap_i2c_isr() · 0cbbcffd
      由 Paul Walmsley 提交于 
      omap_i2c_idle() sets an internal flag, "dev->idle", instructing its
ISR to decline interrupts.  It sets this flag before it actually masks
the interrupts on the I2C controller.  This is problematic, since an
I2C interrupt could arrive after dev->idle is set, but before the
interrupt source is masked.  When this happens, Linux disables the I2C
controller's IRQ, causing all future transactions on the bus to fail.

Symptoms, happening on about 7% of boots:

   irq 56: nobody cared (try booting with the "irqpoll" option)
   <warning traceback here>
   Disabling IRQ #56
   i2c_omap i2c_omap.1: controller timed out

In omap_i2c_idle(), this patch sets dev->idle only after the interrupt
mask write to the I2C controller has left the ARM write buffer.
That's probably the major offender.  For additional prophylaxis, in
omap_i2c_unidle(), the patch clears the dev->idle flag before
interrupts are enabled, rather than afterwards.

The patch has survived twenty-two reboots on the 3430SDP here without
wedging I2C1.  Not absolutely dispositive, but promising!
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>
      0cbbcffd
    • J
      i2c-omap: Do not use interruptible wait call in omap_i2c_xfer_msg · b7af349b
      由 Jarkko Nikula 提交于 
      If there is a signal pending and wait_for_completion_interruptible_timeout
terminates with -ERESTARTSYS, we return and disable the i2c clocks in
omap_i2c_xfer.

If we terminate before sending last i2c message with a stop condition, the
bus remains busy and we are not able to send new messages into bus with
successive omap_i2c_xfer calls. Therefore a pending signal is not caught
here and we return only because of timeout or i2c error.
Signed-off-by: NJarkko Nikula <jarkko.nikula@nokia.com>
Signed-off-by: NJuha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>
      b7af349b
  3. 06 9月, 2008 1 次提交
  5. 23 4月, 2008 1 次提交
  7. 24 3月, 2008 1 次提交
    • T
      i2c-omap: Fix unhandled fault · f08ac4e7
      由 Tony Lindgren 提交于 
      If an I2C interrupt happens between disabling interface clock
and functional clock, the interrupt handler will produce an
external abort on non-linefetch error when trying to access
driver registers while interface clock is disabled.

This patch fixes the problem by saving and disabling i2c-omap
interrupt before turning off the clocks. Also disable functional
clock before the interface clock as suggested by Paul Walmsley.

Patch also renames enable/disable_clocks functions to unidle/idle
functions. Note that the driver is currently not taking advantage
of the idle interrupts. To use the idle interrupts, driver would
have to enable interface clock based on the idle interrupt
and dev->idle flag.

This patch has been tested in linux-omap tree with various omaps.

Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>
      f08ac4e7
  9. 28 1月, 2008 1 次提交
  11. 15 1月, 2008 1 次提交
  13. 12 12月, 2007 1 次提交
  15. 20 10月, 2007 1 次提交
  17. 02 5月, 2007 1 次提交
  19. 11 12月, 2006 1 次提交
  21. 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
  23. 27 9月, 2006 2 次提交