[PATCH v3 2/2] OMAP: IOMMU: add support to callback during fault handling

[David Cohen]

On Mon, Feb 21, 2011 at 10:22 AM, Felipe Balbi <balbi at ti.com> wrote:
> Hi,
>
> On Mon, Feb 21, 2011 at 10:18:56AM +0200, Hiroshi DOYU wrote:
>> From: David Cohen <dacohen at gmail.com>
>> Subject: [PATCH v3 2/2] OMAP: IOMMU: add support to callback during fault handling
>> Date: Wed, 16 Feb 2011 21:35:51 +0200
>>
>> > Add support to register an isr for IOMMU fault situations and adapt it
>> > to allow such (*isr)() to be used as fault callback. Drivers using IOMMU
>> > module might want to be informed when errors happen in order to debug it
>> > or react.
>> >
>> > Signed-off-by: David Cohen <dacohen at gmail.com>
>> > ---
>> >  arch/arm/mach-omap2/iommu2.c            |   17 +++++++++-
>> >  arch/arm/plat-omap/include/plat/iommu.h |   14 ++++++++-
>> >  arch/arm/plat-omap/iommu.c              |   52 ++++++++++++++++++++++---------
>> >  3 files changed, 65 insertions(+), 18 deletions(-)
>> >
>> > diff --git a/arch/arm/mach-omap2/iommu2.c b/arch/arm/mach-omap2/iommu2.c
>> > index 49a1e5e..adb083e 100644
>> > --- a/arch/arm/mach-omap2/iommu2.c
>> > +++ b/arch/arm/mach-omap2/iommu2.c
>> > @@ -146,18 +146,31 @@ static void omap2_iommu_set_twl(struct iommu *obj, bool on)
>> >  static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
>> >  {
>> >     u32 stat, da;
>> > +   u32 errs = 0;
>> >
>> >     stat = iommu_read_reg(obj, MMU_IRQSTATUS);
>> >     stat &= MMU_IRQ_MASK;
>> > -   if (!stat)
>> > +   if (!stat) {
>> > +           *ra = 0;
>> >             return 0;
>> > +   }
>> >
>> >     da = iommu_read_reg(obj, MMU_FAULT_AD);
>> >     *ra = da;
>> >
>> > +   if (stat & MMU_IRQ_TLBMISS)
>> > +           errs |= OMAP_IOMMU_ERR_TLB_MISS;
>> > +   if (stat & MMU_IRQ_TRANSLATIONFAULT)
>> > +           errs |= OMAP_IOMMU_ERR_TRANS_FAULT;
>> > +   if (stat & MMU_IRQ_EMUMISS)
>> > +           errs |= OMAP_IOMMU_ERR_EMU_MISS;
>> > +   if (stat & MMU_IRQ_TABLEWALKFAULT)
>> > +           errs |= OMAP_IOMMU_ERR_TBLWALK_FAULT;
>> > +   if (stat & MMU_IRQ_MULTIHITFAULT)
>> > +           errs |= OMAP_IOMMU_ERR_MULTIHIT_FAULT;
>> >     iommu_write_reg(obj, stat, MMU_IRQSTATUS);
>> >
>> > -   return stat;
>> > +   return errs;
>> >  }
>> >
>> >  static void omap2_tlb_read_cr(struct iommu *obj, struct cr_regs *cr)
>> > diff --git a/arch/arm/plat-omap/include/plat/iommu.h b/arch/arm/plat-omap/include/plat/iommu.h
>> > index 19cbb5e..174f1b9 100644
>> > --- a/arch/arm/plat-omap/include/plat/iommu.h
>> > +++ b/arch/arm/plat-omap/include/plat/iommu.h
>> > @@ -31,6 +31,7 @@ struct iommu {
>> >     struct clk      *clk;
>> >     void __iomem    *regbase;
>> >     struct device   *dev;
>> > +   void            *isr_priv;
>>
>> Ideally I'd like to avoid having "isr_priv" in iommu since it's not
>> used for iommu but client needs the place to pass its info to its
>> custom handler. Any better idea?
>
> I'm not sure if it makes sense as I don't know the mailbox block, but
> maybe moving to GENIRQ ? Then IRQ subsystem would take care of the
> "dev_id"

Not sure if it fits in this case. It's a different module (IOMMU user)
which needs to get a callback from IOMMU when a fault happens.
Is there any GENIRQ usage currently in this scenario?

Br,

David

>
> --
> balbi
>