1. 19 Feb, 2009 4 commits
  2. 17 Feb, 2009 1 commit
    • Nicolas Pitre's avatar
      [ARM] 5401/1: Orion: fix edge triggered GPIO interrupt support · fd4b9b36
      Nicolas Pitre authored
      The GPIO interrupts can be configured as either level triggered or edge
      triggered, with a default of level triggered.  When an edge triggered
      interrupt is requested, the gpio_irq_set_type method is called which
      currently switches the given IRQ descriptor between two struct irq_chip
      instances: orion_gpio_irq_level_chip and orion_gpio_irq_edge_chip. This
      happens via __setup_irq() which also calls irq_chip_set_defaults() to
      assign default methods to uninitialized ones.  The problem is that
      irq_chip_set_defaults() is called before the irq_chip reference is
      switched, leaving the new irq_chip (orion_gpio_irq_edge_chip in this
      case) with uninitialized methods such as chip->startup() causing a kernel
      oops.
      
      Many solutions are possible, such as making irq_chip_set_defaults() global
      and calling it from gpio_irq_set_type(), or calling __irq_set_trigger()
      before irq_chip_set_defaults() in __setup_irq().  But those require
      modifications to the generic IRQ code which might have adverse effect on
      other architectures, and that would still be a fragile arrangement.
      Manually copying the missing methods from within gpio_irq_set_type()
      would be really ugly and it would break again the day new methods with
      automatic defaults are added.
      
      A better solution is to have a single irq_chip instance which can deal
      with both edge and level triggered interrupts.  It is also a good idea
      to switch the IRQ handler instead, as the edge IRQ handler allows for
      one edge IRQ event to be queued as the IRQ is actually masked only when
      that second IRQ is received, at which point the hardware can queue an
      additional IRQ event, making edge triggered interrupts a bit more
      reliable.
      Tested-by: default avatarMartin Michlmayr <tbm@cyrius.com>
      Signed-off-by: default avatarNicolas Pitre <nico@marvell.com>
      Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      fd4b9b36
  3. 16 Feb, 2009 1 commit
  4. 14 Feb, 2009 5 commits
  5. 13 Feb, 2009 29 commits