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

From: ext David Cohen <redacted>
Subject: Re: [PATCH v3 2/2] OMAP: IOMMU: add support to callback during fault handling
Date: Mon, 21 Feb 2011 11:07:01 +0200

On Mon, Feb 21, 2011 at 10:18 AM, Hiroshi DOYU [off-list ref] wrote:

quoted

From: David Cohen <redacted>
Subject: [PATCH v3 2/2] OMAP: IOMMU: add support to callback during fault handling
Date: Wed, 16 Feb 2011 21:35:51 +0200

quoted

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 <redacted>
---
?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?

(*isr)() relies in the same situation, as it belongs to the client.
Without this priv_data, it's necessary to create a global variable to
store client's private data on client side. IMO, it is worse.

Ok, I see. Let's go with this. Thanks.