An error occurred fetching the project authors.
  1. 16 Oct, 2007 1 commit
    • David Brownell's avatar
      SPI driver runtime footprint shrinkage · d1e44d9c
      David Brownell authored
      Shrink the runtime footprint of various SPI drivers:
      
        - Move the probe() routine into the init section where practical,
          using platform_driver_probe() to make that safe.  This often saves
          around 1KB.  Using platform_driver_probe() can also be a correctness
          fix, if the probe routine is already marked __init but the driver
          struct keeps a dangling pointer to it after init section removal.
      
        - Likewise move remove() routines into the exit sections.
      
      These changes would be inappropriate iff the platform devices were
      actually hotpluggable (e.g. they're found on optional addon cards,
      or in an FPGA that's dynamically reprogrammed).  In these cases,
      that's not the situation; it's an SOC controller and the only device
      is initialized before these drivers.
      Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d1e44d9c
  2. 12 Sep, 2007 1 commit
  3. 31 Aug, 2007 1 commit
    • David Brownell's avatar
      SPI driver hotplug/coldplug fixes · fc3ba952
      David Brownell authored
      Update various SPI drivers so they properly support
      
        - coldplug through "modprobe $(cat /sys/devices/.../modalias)"
      
        - hotplug through "modprobe $(MODALIAS)"
      
      The basic rule for platform, SPI, and (new style) I2C drivers is just
      to make sure that modprobing the driver name works.  In this case, all
      the relevant drivers are platform drivers, and this patch either
      
        (a)	Changes the driver name, if no in-tree code would break;
      	this is simpler and thus preferable in the long term.
      
        (b)	Adds MODULE_ALIAS directives, when in-tree platforms declare
      	devices using the current driver name; less desirable.
      
      Most systems will link SPI controller drivers statically, but
      there's no point in being needlessly broken.
      Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
      Cc: Jean Delvare <khali@linux-fr.org>
      Acked-by: default avatarAndrei Konovalov <akonovalov@ru.mvista.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fc3ba952
  4. 11 Aug, 2007 2 commits
  5. 31 Jul, 2007 5 commits
  6. 17 Jul, 2007 3 commits
  7. 30 Dec, 2006 1 commit
    • David Brownell's avatar
      [PATCH] SPI: define null tx_buf to mean "shift out zeroes" · 4b1badf5
      David Brownell authored
      Some issues were recently turned up with the current specification of what
      it means for spi_transfer.tx_buf to be null, as part of transfers which are
      (from the SPI protocol driver perspective) pure reads.
      
      Specifically, that it seems better to change the TX behaviour there from
      "undefined" to "will shift zeroes".  This lets protocol drivers (like the
      ads7846 driver) depend on that behavior.  It's what most controller drivers
      in the tree are already doing (with one exception and one case of driver
      wanting-to-oops), it's what Microwire hardware will necessarily be doing,
      and it removes an issue whereby certain security audits would need to
      define such a value anyway as part of removing covert channels.
      
      This patch changes the specification to require shifting zeroes, and
      updates all currently merged SPI controller drivers to do so.
      Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
      Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      4b1badf5
  8. 05 Oct, 2006 1 commit
    • David Howells's avatar
      IRQ: Maintain regs pointer globally rather than passing to IRQ handlers · 7d12e780
      David Howells authored
      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: default avatarDavid Howells <dhowells@redhat.com>
      (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
      7d12e780
  9. 21 May, 2006 1 commit