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Re: [PATCH 02/10] Alchemy: Au1300 new interrupt controller

To: Manuel Lauss <mano@roarinelk.homelinux.net>
Subject: Re: [PATCH 02/10] Alchemy: Au1300 new interrupt controller
From: Kevin Hickey <khickey@rmicorp.com>
Date: Sat, 07 Mar 2009 13:20:08 -0600
Cc: ralf@linux-mips.org, linux-mips@linux-mips.org
In-reply-to: <20090307104932.49408650@scarran.roarinelk.net>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <1236356409-32357-1-git-send-email-khickey@rmicorp.com> <788248524efc28ba2608ed79bfb7080ee476b12d.1236354153.git.khickey@rmicorp.com> <0b447f7e26be90a9179bdf89ca2cfd1f34c5d16e.1236354153.git.khickey@rmicorp.com> <20090307104932.49408650@scarran.roarinelk.net>
Sender: linux-mips-bounce@linux-mips.org
On Sat, 2009-03-07 at 10:49 +0100, Manuel Lauss wrote:
> On Fri,  6 Mar 2009 10:20:01 -0600
> Kevin Hickey <khickey@rmicorp.com> wrote:
> 
> > The Au1300 has a new interrupt controller (relative to the rest of the 
> > Alchemy
> > line).  The differences were great enough to justify adding a whole new 
> > module.
> > Included in this patch is the new interrupt controller, a new 
> > implementation of
> > the cascade interrupt controller on the DB1300 board and some code to drive
> > LEDs on the DB1300 that is used by the interrupt controller.
> > 
> > A small change was made to the existing interrupt controller; it is "ifdef'd
> > out" for Au1300.
> > 
> > Since the cascade interrupt controller is virtually indentical (with the
> > exception of some constants) between the DB1300 and DB1200, a future
> > optimization may be to use the same code for both boards.
> 
> > diff --git a/arch/mips/alchemy/common/Makefile 
> > b/arch/mips/alchemy/common/Makefile
> > index d50d476..85ffa2e 100644
> > --- a/arch/mips/alchemy/common/Makefile
> > +++ b/arch/mips/alchemy/common/Makefile
> > @@ -7,7 +7,9 @@
> > 
> >  obj-y += prom.o irq.o puts.o time.o reset.o \
> >     clocks.o platform.o power.o setup.o \
> > -   sleeper.o dma.o dbdma.o gpio.o
> > +   sleeper.o dma.o dbdma.o gpio.o gpio_int.o
> > +
> > +obj-$(CONFIG_SOC_AU13XX) += au13xx_res.o
> 
> belongs to another patch in the series?
Yes, but git-add wouldn't let me split the hunk so I just left it...
figured the series would be taken as a whole anyway.
> 
> 
> > diff --git a/arch/mips/alchemy/common/gpio_int.c 
> > b/arch/mips/alchemy/common/gpio_int.c
> > new file mode 100644
> > index 0000000..c09b793
> > --- /dev/null
> > +++ b/arch/mips/alchemy/common/gpio_int.c
> > @@ -0,0 +1,268 @@
> > +/*
> > + * Copyright 2008 RMI Corporation
> > + * Author: Kevin Hickey <khickey@rmicorp.com>
> > + *
> > + *  This program is free software; you can redistribute  it and/or modify 
> > it
> > + *  under  the terms of  the GNU General  Public License as published by 
> > the
> > + *  Free Software Foundation;  either version 2 of the  License, or (at 
> > your
> > + *  option) any later version.
> > + *
> > + *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
> > + *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES 
> > OF
> > + *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  
> > IN
> > + *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
> > + *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
> > BUT
> > + *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS 
> > OF
> > + *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND 
> > ON
> > + *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR 
> > TORT
> > + *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
> > OF
> > + *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> > + *
> > + *  You should have received a copy of the  GNU General Public License 
> > along
> > + *  with this program; if not, write  to the Free Software Foundation, 
> > Inc.,
> > + *  675 Mass Ave, Cambridge, MA 02139, USA.
> > + */
> > +
> > +#ifdef CONFIG_AU_GPIO_INT_CNTLR
> > +
> > +#include <linux/irq.h>
> > +#include <linux/init.h>
> > +#include <linux/interrupt.h>               /* For functions called by 
> > do_IRQ */
> > +#include <asm/irq_cpu.h>
> > +
> > +#include <asm/mach-au1x00/gpio_int.h>
> > +#include <asm/mach-au1x00/au1000.h>
> > +
> > +#include <dev_boards.h>
> 
> Please try to keep common/ free of anything not related to the chip
> itself.
> 
I have board_irq_dispatch() in there.  I should move that to some other
non-dev-board specific include.
> 
> 
> > +asmlinkage void plat_irq_dispatch(void)
> > +{
> > +   unsigned int intr;
> > +   u32 bank;
> > +   u32 reg_msk;
> > +   unsigned int pending = read_c0_status() & read_c0_cause();
> > +   /*
> > +    * C0 timer tick
> > +    */
> > +   if (pending & CAUSEF_IP7)
> > +           do_IRQ(MIPS_CPU_IRQ_BASE + 7);
> > +   else if (pending & (CAUSEF_IP2 | CAUSEF_IP3)) {
> > +           intr = au_ioread32(&gpio_int->pri_enc);
> > +           bank = GPINT_BANK_FROM_INT(intr);
> > +           reg_msk = GPINT_BIT_FROM_INT(bank, intr);
> > +
> > +           if (intr != 127) {
> > +                   if (pending & CAUSEF_IP3)
> > +                           board_irq_dispatch(intr);
> 
> What is this supposed to do? (missed debug code?)
board_irq_dispatch (which as I said above should be in a non-devboard
include) is used to display the IRQ number on the hex LEDs on the DB1300
board.  I tried to keep it generic so that other boards could do what
they want or leave it unimplemented and have it optimized out.  The
CAUSEF_IP3 part is there to not display the timer tick (since it pretty
much floods out the other IRQ displays).  I should really do that
segregation in the board_irq_dispatch call; I was pretty focused on my
board when I wrote this code.
> 
> > +
> > +                   do_IRQ(GPINT_LINUX_IRQ_OFFSET + intr);
> > +           }
> > +   } else {
> > +           printk(KERN_WARNING
> > +                   "ALCHEMY GPIO_INT: Unexpected cause was set. %08x\n",
> > +                   pending);
> > +   }
> 
> should probably call spurious_interrupt() here.
Agreed.
> 
> 
> > +
> > +}
> > +
> > +#endif
> > diff --git a/arch/mips/alchemy/common/irq.c b/arch/mips/alchemy/common/irq.c
> > index c88c821..f8742dd 100644
> > --- a/arch/mips/alchemy/common/irq.c
> > +++ b/arch/mips/alchemy/common/irq.c
> > @@ -24,6 +24,7 @@
> >   *  with this program; if not, write  to the Free Software Foundation, 
> > Inc.,
> >   *  675 Mass Ave, Cambridge, MA 02139, USA.
> >   */
> > +#ifdef CONFIG_AU_INT_CNTLR
> > 
> >  #include <linux/bitops.h>
> >  #include <linux/init.h>
> > @@ -609,3 +610,5 @@ void __init arch_init_irq(void)
> > 
> >     set_c0_status(IE_IRQ0 | IE_IRQ1 | IE_IRQ2 | IE_IRQ3);
> >  }
> > +
> > +#endif
> 
> Why not make compilation of the original irq.c file dependent on
> AU_INT_CNTRL?  (i.e. change the Makefile to
> obj-$(CONFIG_AU_INT_CNTRL) += irq.o
> for non-au1300 parts).
Good idea.  I'm still getting used to some of the build system options
so they're not always instinct.
> 
> (FWIW, I'm working on getting rid of the explicit CPU-type config
> options and instead do runtime detection and configuration of
> dma/dbdma/irq/ and so on).

Why?  Won't that just lead to a larger kernel binary since it will have
all of the tables in it?  I would prefer to only compile in the data
that I need.  Unless I'm missing what you're doing...
> 
> 
> Best regards,
>       Manuel Lauss
-- 
Kevin Hickey
Alchemy Solutions
RMI Corporation
khickey@rmicorp.com
P:  512.691.8044


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