From: David Cohen <dacohen@xxxxxxxxx>
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@xxxxxxxxx>
> ---
> 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?
> unsigned int refcount;
> struct mutex iommu_lock; /* global for this whole object */
> @@ -47,7 +48,7 @@ struct iommu {
> struct list_head mmap;
> struct mutex mmap_lock; /* protect mmap */
>
> - int (*isr)(struct iommu *obj);
> + int (*isr)(struct iommu *obj, u32 da, u32 iommu_errs, void *priv);
>
> void *ctx; /* iommu context: registres saved area */
> u32 da_start;
> @@ -109,6 +110,13 @@ struct iommu_platform_data {
> u32 da_end;
> };
>
> +/* IOMMU errors */
> +#define OMAP_IOMMU_ERR_TLB_MISS (1 << 0)
> +#define OMAP_IOMMU_ERR_TRANS_FAULT (1 << 1)
> +#define OMAP_IOMMU_ERR_EMU_MISS (1 << 2)
> +#define OMAP_IOMMU_ERR_TBLWALK_FAULT (1 << 3)
> +#define OMAP_IOMMU_ERR_MULTIHIT_FAULT (1 << 4)
> +
> #if defined(CONFIG_ARCH_OMAP1)
> #error "iommu for this processor not implemented yet"
> #else
> @@ -161,6 +169,10 @@ extern size_t iopgtable_clear_entry(struct iommu *obj, u32 iova);
> extern int iommu_set_da_range(struct iommu *obj, u32 start, u32 end);
> extern struct iommu *iommu_get(const char *name);
> extern void iommu_put(struct iommu *obj);
> +extern int iommu_set_isr(const char *name,
> + int (*isr)(struct iommu *obj, u32 da, u32 iommu_errs,
> + void *priv),
> + void *isr_priv);
>
> extern void iommu_save_ctx(struct iommu *obj);
> extern void iommu_restore_ctx(struct iommu *obj);
> diff --git a/arch/arm/plat-omap/iommu.c b/arch/arm/plat-omap/iommu.c
> index f55f458..b0e0efc 100644
> --- a/arch/arm/plat-omap/iommu.c
> +++ b/arch/arm/plat-omap/iommu.c
> @@ -780,25 +780,19 @@ static void iopgtable_clear_entry_all(struct iommu *obj)
> */
> static irqreturn_t iommu_fault_handler(int irq, void *data)
> {
> - u32 stat, da;
> + u32 da, errs;
> u32 *iopgd, *iopte;
> - int err = -EIO;
> struct iommu *obj = data;
>
> if (!obj->refcount)
> return IRQ_NONE;
>
> - /* Dynamic loading TLB or PTE */
> - if (obj->isr)
> - err = obj->isr(obj);
> -
> - if (!err)
> - return IRQ_HANDLED;
> -
> clk_enable(obj->clk);
> - stat = iommu_report_fault(obj, &da);
> + errs = iommu_report_fault(obj, &da);
> clk_disable(obj->clk);
> - if (!stat)
> +
> + /* Fault callback or TLB/PTE Dynamic loading */
> + if (obj->isr && !obj->isr(obj, da, errs, obj->isr_priv))
> return IRQ_HANDLED;
>
> iommu_disable(obj);
> @@ -806,15 +800,16 @@ static irqreturn_t iommu_fault_handler(int irq, void *data)
> iopgd = iopgd_offset(obj, da);
>
> if (!iopgd_is_table(*iopgd)) {
> - dev_err(obj->dev, "%s: da:%08x pgd:%p *pgd:%08x\n", obj->name,
> - da, iopgd, *iopgd);
> + dev_err(obj->dev, "%s: errs:0x%08x da:0x%08x pgd:0x%p "
> + "*pgd:px%08x\n", obj->name, errs, da, iopgd, *iopgd);
> return IRQ_NONE;
> }
>
> iopte = iopte_offset(iopgd, da);
>
> - dev_err(obj->dev, "%s: da:%08x pgd:%p *pgd:%08x pte:%p *pte:%08x\n",
> - obj->name, da, iopgd, *iopgd, iopte, *iopte);
> + dev_err(obj->dev, "%s: errs:0x%08x da:0x%08x pgd:0x%p *pgd:0x%08x "
> + "pte:0x%p *pte:0x%08x\n", obj->name, errs, da, iopgd, *iopgd,
> + iopte, *iopte);
>
> return IRQ_NONE;
> }
> @@ -917,6 +912,33 @@ void iommu_put(struct iommu *obj)
> }
> EXPORT_SYMBOL_GPL(iommu_put);
>
> +int iommu_set_isr(const char *name,
> + int (*isr)(struct iommu *obj, u32 da, u32 iommu_errs,
> + void *priv),
> + void *isr_priv)
> +{
> + struct device *dev;
> + struct iommu *obj;
> +
> + dev = driver_find_device(&omap_iommu_driver.driver, NULL, (void *)name,
> + device_match_by_alias);
> + if (!dev)
> + return -ENODEV;
> +
> + obj = to_iommu(dev);
> + mutex_lock(&obj->iommu_lock);
> + if (obj->refcount != 0) {
> + mutex_unlock(&obj->iommu_lock);
> + return -EBUSY;
> + }
> + obj->isr = isr;
> + obj->isr_priv = isr_priv;
> + mutex_unlock(&obj->iommu_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(iommu_set_isr);
> +
> /*
> * OMAP Device MMU(IOMMU) detection
> */
> --
> 1.7.2.3
>
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