[PATCH v2 0/1] OMAP: IOMMU fault callback support

[PATCH v2 0/1] OMAP: IOMMU fault callback support

[David Cohen]

Hi,

v2:

Previous patch 1/2 on v1 was dropped.

---

v1:

This patch set adds fault callback support to allow IOMMU users to debug or
react when a fault happens.
IOMMU faults might be very difficult to reproduce and then to figure out
the source of the problem. Currently IOMMU driver prints not so useful
debug message and does not notice user about such issue.
With a fault callback, IOMMU user may debug much more useful information
and/or react to go back to a valid state.

Br,

David
---

David Cohen (1):
  OMAP: IOMMU: add support to callback during fault handling

 arch/arm/mach-omap2/iommu2.c            |   21 +++++++++++++--
 arch/arm/plat-omap/include/plat/iommu.h |   15 ++++++++++-
 arch/arm/plat-omap/iommu.c              |   41 ++++++++++++++++++++++++++++---
 3 files changed, 69 insertions(+), 8 deletions(-)

-- 
1.7.2.3

[PATCH v2 1/1] OMAP: IOMMU: add support to callback during fault handling

[David Cohen]

Add support to register a callback for IOMMU fault situations. Drivers using
IOMMU module might want to be informed when such errors happen in order to
debug it or react.

Signed-off-by: David Cohen <dacohen@gmail.com>
---
 arch/arm/mach-omap2/iommu2.c            |   21 +++++++++++++--
 arch/arm/plat-omap/include/plat/iommu.h |   15 ++++++++++-
 arch/arm/plat-omap/iommu.c              |   41 ++++++++++++++++++++++++++++---
 3 files changed, 69 insertions(+), 8 deletions(-)

diff --git a/arch/arm/mach-omap2/iommu2.c b/arch/arm/mach-omap2/iommu2.c
index 14ee686..504310d 100644
--- a/arch/arm/mach-omap2/iommu2.c
+++ b/arch/arm/mach-omap2/iommu2.c
@@ -143,10 +143,10 @@ static void omap2_iommu_set_twl(struct iommu *obj, bool on)
 	__iommu_set_twl(obj, false);
 }
 
-static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
+static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra, u32 *iommu_errs)
 {
 	int i;
-	u32 stat, da;
+	u32 stat, da, errs;
 	const char *err_msg[] =	{
 		"tlb miss",
 		"translation fault",
@@ -157,8 +157,10 @@ static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
 
 	stat = iommu_read_reg(obj, MMU_IRQSTATUS);
 	stat &= MMU_IRQ_MASK;
-	if (!stat)
+	if (!stat) {
+		*iommu_errs = 0;
 		return 0;
+	}
 
 	da = iommu_read_reg(obj, MMU_FAULT_AD);
 	*ra = da;
@@ -171,6 +173,19 @@ static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
 	}
 	printk("\n");
 
+	errs = 0;
+	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_errs = errs;
+
 	iommu_write_reg(obj, stat, MMU_IRQSTATUS);
 
 	return stat;
diff --git a/arch/arm/plat-omap/include/plat/iommu.h b/arch/arm/plat-omap/include/plat/iommu.h
index 19cbb5e..5a2475f 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		*fault_cb_priv;
 
 	unsigned int	refcount;
 	struct mutex	iommu_lock;	/* global for this whole object */
@@ -48,6 +49,7 @@ struct iommu {
 	struct mutex		mmap_lock; /* protect mmap */
 
 	int (*isr)(struct iommu *obj);
+	void (*fault_cb)(struct iommu *obj, u32 da, u32 iommu_errs, void *priv);
 
 	void *ctx; /* iommu context: registres saved area */
 	u32 da_start;
@@ -83,7 +85,7 @@ struct iommu_functions {
 	int (*enable)(struct iommu *obj);
 	void (*disable)(struct iommu *obj);
 	void (*set_twl)(struct iommu *obj, bool on);
-	u32 (*fault_isr)(struct iommu *obj, u32 *ra);
+	u32 (*fault_isr)(struct iommu *obj, u32 *ra, u32 *iommu_errs);
 
 	void (*tlb_read_cr)(struct iommu *obj, struct cr_regs *cr);
 	void (*tlb_load_cr)(struct iommu *obj, struct cr_regs *cr);
@@ -109,6 +111,13 @@ 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 +170,10 @@ 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_fault_callback(const char *name,
+				    void (*fault_cb)(struct iommu *obj, u32 da,
+						     u32 errs, void *priv),
+				    void *fault_cb_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 b1107c0..7f780ee 100644
--- a/arch/arm/plat-omap/iommu.c
+++ b/arch/arm/plat-omap/iommu.c
@@ -163,9 +163,9 @@ static u32 get_iopte_attr(struct iotlb_entry *e)
 	return arch_iommu->get_pte_attr(e);
 }
 
-static u32 iommu_report_fault(struct iommu *obj, u32 *da)
+static u32 iommu_report_fault(struct iommu *obj, u32 *da, u32 *iommu_errs)
 {
-	return arch_iommu->fault_isr(obj, da);
+	return arch_iommu->fault_isr(obj, da, iommu_errs);
 }
 
 static void iotlb_lock_get(struct iommu *obj, struct iotlb_lock *l)
@@ -780,7 +780,7 @@ static void iopgtable_clear_entry_all(struct iommu *obj)
  */
 static irqreturn_t iommu_fault_handler(int irq, void *data)
 {
-	u32 stat, da;
+	u32 stat, da, errs;
 	u32 *iopgd, *iopte;
 	int err = -EIO;
 	struct iommu *obj = data;
@@ -796,13 +796,19 @@ static irqreturn_t iommu_fault_handler(int irq, void *data)
 		return IRQ_HANDLED;
 
 	clk_enable(obj->clk);
-	stat = iommu_report_fault(obj, &da);
+	stat = iommu_report_fault(obj, &da, &errs);
 	clk_disable(obj->clk);
 	if (!stat)
 		return IRQ_HANDLED;
 
 	iommu_disable(obj);
 
+	if (obj->fault_cb) {
+		obj->fault_cb(obj, da, errs, obj->fault_cb_priv);
+		/* No need to print error message as callback is called */
+		return IRQ_NONE;
+	}
+
 	iopgd = iopgd_offset(obj, da);
 
 	if (!iopgd_is_table(*iopgd)) {
@@ -917,6 +923,33 @@ void iommu_put(struct iommu *obj)
 }
 EXPORT_SYMBOL_GPL(iommu_put);
 
+int iommu_set_fault_callback(const char *name,
+			     void (*fault_cb)(struct iommu *obj, u32 da,
+					      u32 iommu_errs, void *priv),
+			     void *fault_cb_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->fault_cb = fault_cb;
+	obj->fault_cb_priv = fault_cb_priv;
+	mutex_unlock(&obj->iommu_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iommu_set_fault_callback);
+
 /*
  *	OMAP Device MMU(IOMMU) detection
  */
-- 
1.7.2.3

[PATCH v2 1/1] OMAP: IOMMU: add support to callback during fault handling

[Hiroshi DOYU]

Hi David,

Sorry for a bit late reply....

From: David Cohen <dacohen@gmail.com>
Subject: [PATCH v2 1/1] OMAP: IOMMU: add support to callback during fault handling
Date: Tue, 15 Feb 2011 16:36:31 +0200

> Add support to register a callback for IOMMU fault situations. Drivers using
> IOMMU module might want to be informed when such errors happen in order to
> debug it or react.
> 
> Signed-off-by: David Cohen <dacohen@gmail.com>
> ---
>  arch/arm/mach-omap2/iommu2.c            |   21 +++++++++++++--
>  arch/arm/plat-omap/include/plat/iommu.h |   15 ++++++++++-
>  arch/arm/plat-omap/iommu.c              |   41 ++++++++++++++++++++++++++++---
>  3 files changed, 69 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/iommu2.c b/arch/arm/mach-omap2/iommu2.c
> index 14ee686..504310d 100644
> --- a/arch/arm/mach-omap2/iommu2.c
> +++ b/arch/arm/mach-omap2/iommu2.c
> @@ -143,10 +143,10 @@ static void omap2_iommu_set_twl(struct iommu *obj, bool on)
>  	__iommu_set_twl(obj, false);
>  }
>  
> -static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
> +static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra, u32 *iommu_errs)
>  {
>  	int i;
> -	u32 stat, da;
> +	u32 stat, da, errs;
>  	const char *err_msg[] =	{
>  		"tlb miss",
>  		"translation fault",
> @@ -157,8 +157,10 @@ static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
>  
>  	stat = iommu_read_reg(obj, MMU_IRQSTATUS);
>  	stat &= MMU_IRQ_MASK;
> -	if (!stat)
> +	if (!stat) {
> +		*iommu_errs = 0;
>  		return 0;
> +	}
>  
>  	da = iommu_read_reg(obj, MMU_FAULT_AD);
>  	*ra = da;
> @@ -171,6 +173,19 @@ static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
>  	}
>  	printk("\n");
>  
> +	errs = 0;
> +	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_errs = errs;
> +
>  	iommu_write_reg(obj, stat, MMU_IRQSTATUS);
>  
>  	return stat;
> diff --git a/arch/arm/plat-omap/include/plat/iommu.h b/arch/arm/plat-omap/include/plat/iommu.h
> index 19cbb5e..5a2475f 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		*fault_cb_priv;
>  
>  	unsigned int	refcount;
>  	struct mutex	iommu_lock;	/* global for this whole object */
> @@ -48,6 +49,7 @@ struct iommu {
>  	struct mutex		mmap_lock; /* protect mmap */
>  
>  	int (*isr)(struct iommu *obj);
> +	void (*fault_cb)(struct iommu *obj, u32 da, u32 iommu_errs, void *priv);

What about making use of (*isr)() for fault call back as well?

Basic concept is that, client can decide how to deal with iommu
fault. For example, for advanced case, client wants daynamic loading of
TLB(or PTE), or for ISP case, clients just want more appropriate fault
reporting. This (*isr)() could be used in such flexibility.

   785   *      Device IOMMU generic operations
   786   */
   787  static irqreturn_t iommu_fault_handler(int irq, void *data)
   788  {
   789          u32 stat, da;
   790          u32 *iopgd, *iopte;
   791          int err = -EIO;
   792          struct iommu *obj = data;
   793  
   794          if (!obj->refcount)
   795                  return IRQ_NONE;
   796  
   797          /* Dynamic loading TLB or PTE */
   798          if (obj->isr)
   799                  err = obj->isr(obj);
   800  
   801          if (!err)
   802                  return IRQ_HANDLED;
   803  
   804          clk_enable(obj->clk);
   805          stat = iommu_report_fault(obj, &da);
   806          clk_disable(obj->clk);
   807          if (!stat)
   808                  return IRQ_HANDLED;
   809  
   810          iommu_disable(obj);

I guess that this modifying the above code could make (*isr)()
flexible to be used for any purpose for clients? For me, having both
following may be a bit residual.

>  	int (*isr)(struct iommu *obj);
> +	void (*fault_cb)(struct iommu *obj, u32 da, u32 iommu_errs, void *priv);

[PATCH v2 1/1] OMAP: IOMMU: add support to callback during fault handling

[David Cohen]

On Tue, Feb 15, 2011 at 4:48 PM, Hiroshi DOYU <Hiroshi.DOYU@nokia.com> wrote:
> Hi David,

Hi Hiroshi,

>
> Sorry for a bit late reply....

You're just in time. :)

>
> From: David Cohen <dacohen@gmail.com>
> Subject: [PATCH v2 1/1] OMAP: IOMMU: add support to callback during fault handling
> Date: Tue, 15 Feb 2011 16:36:31 +0200
>
>> Add support to register a callback for IOMMU fault situations. Drivers using
>> IOMMU module might want to be informed when such errors happen in order to
>> debug it or react.
>>
>> Signed-off-by: David Cohen <dacohen@gmail.com>
>> ---
>> ?arch/arm/mach-omap2/iommu2.c ? ? ? ? ? ?| ? 21 +++++++++++++--
>> ?arch/arm/plat-omap/include/plat/iommu.h | ? 15 ++++++++++-
>> ?arch/arm/plat-omap/iommu.c ? ? ? ? ? ? ?| ? 41 ++++++++++++++++++++++++++++---
>> ?3 files changed, 69 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/iommu2.c b/arch/arm/mach-omap2/iommu2.c
>> index 14ee686..504310d 100644
>> --- a/arch/arm/mach-omap2/iommu2.c
>> +++ b/arch/arm/mach-omap2/iommu2.c
>> @@ -143,10 +143,10 @@ static void omap2_iommu_set_twl(struct iommu *obj, bool on)
>> ? ? ? __iommu_set_twl(obj, false);
>> ?}
>>
>> -static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
>> +static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra, u32 *iommu_errs)
>> ?{
>> ? ? ? int i;
>> - ? ? u32 stat, da;
>> + ? ? u32 stat, da, errs;
>> ? ? ? const char *err_msg[] = {
>> ? ? ? ? ? ? ? "tlb miss",
>> ? ? ? ? ? ? ? "translation fault",
>> @@ -157,8 +157,10 @@ static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
>>
>> ? ? ? stat = iommu_read_reg(obj, MMU_IRQSTATUS);
>> ? ? ? stat &= MMU_IRQ_MASK;
>> - ? ? if (!stat)
>> + ? ? if (!stat) {
>> + ? ? ? ? ? ? *iommu_errs = 0;
>> ? ? ? ? ? ? ? return 0;
>> + ? ? }
>>
>> ? ? ? da = iommu_read_reg(obj, MMU_FAULT_AD);
>> ? ? ? *ra = da;
>> @@ -171,6 +173,19 @@ static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
>> ? ? ? }
>> ? ? ? printk("\n");
>>
>> + ? ? errs = 0;
>> + ? ? 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_errs = errs;
>> +
>> ? ? ? iommu_write_reg(obj, stat, MMU_IRQSTATUS);
>>
>> ? ? ? return stat;
>> diff --git a/arch/arm/plat-omap/include/plat/iommu.h b/arch/arm/plat-omap/include/plat/iommu.h
>> index 19cbb5e..5a2475f 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 ? ? ? ? ? ?*fault_cb_priv;
>>
>> ? ? ? unsigned int ? ?refcount;
>> ? ? ? struct mutex ? ?iommu_lock; ? ? /* global for this whole object */
>> @@ -48,6 +49,7 @@ struct iommu {
>> ? ? ? struct mutex ? ? ? ? ? ?mmap_lock; /* protect mmap */
>>
>> ? ? ? int (*isr)(struct iommu *obj);
>> + ? ? void (*fault_cb)(struct iommu *obj, u32 da, u32 iommu_errs, void *priv);
>
> What about making use of (*isr)() for fault call back as well?
>
> Basic concept is that, client can decide how to deal with iommu
> fault. For example, for advanced case, client wants daynamic loading of
> TLB(or PTE), or for ISP case, clients just want more appropriate fault
> reporting. This (*isr)() could be used in such flexibility.

In this case, it seems we can re-use it.

>
> ? 785 ? * ? ? ?Device IOMMU generic operations
> ? 786 ? */
> ? 787 ?static irqreturn_t iommu_fault_handler(int irq, void *data)
> ? 788 ?{
> ? 789 ? ? ? ? ?u32 stat, da;
> ? 790 ? ? ? ? ?u32 *iopgd, *iopte;
> ? 791 ? ? ? ? ?int err = -EIO;
> ? 792 ? ? ? ? ?struct iommu *obj = data;
> ? 793
> ? 794 ? ? ? ? ?if (!obj->refcount)
> ? 795 ? ? ? ? ? ? ? ? ?return IRQ_NONE;
> ? 796
> ? 797 ? ? ? ? ?/* Dynamic loading TLB or PTE */
> ? 798 ? ? ? ? ?if (obj->isr)
> ? 799 ? ? ? ? ? ? ? ? ?err = obj->isr(obj);
> ? 800
> ? 801 ? ? ? ? ?if (!err)
> ? 802 ? ? ? ? ? ? ? ? ?return IRQ_HANDLED;
> ? 803
> ? 804 ? ? ? ? ?clk_enable(obj->clk);
> ? 805 ? ? ? ? ?stat = iommu_report_fault(obj, &da);
> ? 806 ? ? ? ? ?clk_disable(obj->clk);
> ? 807 ? ? ? ? ?if (!stat)
> ? 808 ? ? ? ? ? ? ? ? ?return IRQ_HANDLED;
> ? 809
> ? 810 ? ? ? ? ?iommu_disable(obj);
>
> I guess that this modifying the above code could make (*isr)()
> flexible to be used for any purpose for clients? For me, having both
> following may be a bit residual.

I agree. We need to add 'void *isr_priv' to iommu struct and the
function to register isr.
I'll send a v3 soon.

Regards,

David

>
>> ? ? ? int (*isr)(struct iommu *obj);
>> + ? ? void (*fault_cb)(struct iommu *obj, u32 da, u32 iommu_errs, void *priv);
>

[PATCH v2 1/1] OMAP: IOMMU: add support to callback during fault handling

[David Cohen]

On Tue, Feb 15, 2011 at 5:10 PM, David Cohen <dacohen@gmail.com> wrote:
> On Tue, Feb 15, 2011 at 4:48 PM, Hiroshi DOYU <Hiroshi.DOYU@nokia.com> wrote:
>> Hi David,
>
> Hi Hiroshi,
>
>>
>> Sorry for a bit late reply....
>
> You're just in time. :)
>
>>
>> From: David Cohen <dacohen@gmail.com>
>> Subject: [PATCH v2 1/1] OMAP: IOMMU: add support to callback during fault handling
>> Date: Tue, 15 Feb 2011 16:36:31 +0200
>>
>>> Add support to register a callback for IOMMU fault situations. Drivers using
>>> IOMMU module might want to be informed when such errors happen in order to
>>> debug it or react.
>>>
>>> Signed-off-by: David Cohen <dacohen@gmail.com>
>>> ---
>>> ?arch/arm/mach-omap2/iommu2.c ? ? ? ? ? ?| ? 21 +++++++++++++--
>>> ?arch/arm/plat-omap/include/plat/iommu.h | ? 15 ++++++++++-
>>> ?arch/arm/plat-omap/iommu.c ? ? ? ? ? ? ?| ? 41 ++++++++++++++++++++++++++++---
>>> ?3 files changed, 69 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/arch/arm/mach-omap2/iommu2.c b/arch/arm/mach-omap2/iommu2.c
>>> index 14ee686..504310d 100644
>>> --- a/arch/arm/mach-omap2/iommu2.c
>>> +++ b/arch/arm/mach-omap2/iommu2.c
>>> @@ -143,10 +143,10 @@ static void omap2_iommu_set_twl(struct iommu *obj, bool on)
>>> ? ? ? __iommu_set_twl(obj, false);
>>> ?}
>>>
>>> -static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
>>> +static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra, u32 *iommu_errs)
>>> ?{
>>> ? ? ? int i;
>>> - ? ? u32 stat, da;
>>> + ? ? u32 stat, da, errs;
>>> ? ? ? const char *err_msg[] = {
>>> ? ? ? ? ? ? ? "tlb miss",
>>> ? ? ? ? ? ? ? "translation fault",
>>> @@ -157,8 +157,10 @@ static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
>>>
>>> ? ? ? stat = iommu_read_reg(obj, MMU_IRQSTATUS);
>>> ? ? ? stat &= MMU_IRQ_MASK;
>>> - ? ? if (!stat)
>>> + ? ? if (!stat) {
>>> + ? ? ? ? ? ? *iommu_errs = 0;
>>> ? ? ? ? ? ? ? return 0;
>>> + ? ? }
>>>
>>> ? ? ? da = iommu_read_reg(obj, MMU_FAULT_AD);
>>> ? ? ? *ra = da;
>>> @@ -171,6 +173,19 @@ static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
>>> ? ? ? }
>>> ? ? ? printk("\n");
>>>
>>> + ? ? errs = 0;
>>> + ? ? 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_errs = errs;
>>> +
>>> ? ? ? iommu_write_reg(obj, stat, MMU_IRQSTATUS);
>>>
>>> ? ? ? return stat;
>>> diff --git a/arch/arm/plat-omap/include/plat/iommu.h b/arch/arm/plat-omap/include/plat/iommu.h
>>> index 19cbb5e..5a2475f 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 ? ? ? ? ? ?*fault_cb_priv;
>>>
>>> ? ? ? unsigned int ? ?refcount;
>>> ? ? ? struct mutex ? ?iommu_lock; ? ? /* global for this whole object */
>>> @@ -48,6 +49,7 @@ struct iommu {
>>> ? ? ? struct mutex ? ? ? ? ? ?mmap_lock; /* protect mmap */
>>>
>>> ? ? ? int (*isr)(struct iommu *obj);
>>> + ? ? void (*fault_cb)(struct iommu *obj, u32 da, u32 iommu_errs, void *priv);
>>
>> What about making use of (*isr)() for fault call back as well?
>>
>> Basic concept is that, client can decide how to deal with iommu
>> fault. For example, for advanced case, client wants daynamic loading of
>> TLB(or PTE), or for ISP case, clients just want more appropriate fault
>> reporting. This (*isr)() could be used in such flexibility.
>
> In this case, it seems we can re-use it.
>
>>
>> ? 785 ? * ? ? ?Device IOMMU generic operations
>> ? 786 ? */
>> ? 787 ?static irqreturn_t iommu_fault_handler(int irq, void *data)
>> ? 788 ?{
>> ? 789 ? ? ? ? ?u32 stat, da;
>> ? 790 ? ? ? ? ?u32 *iopgd, *iopte;
>> ? 791 ? ? ? ? ?int err = -EIO;
>> ? 792 ? ? ? ? ?struct iommu *obj = data;
>> ? 793
>> ? 794 ? ? ? ? ?if (!obj->refcount)
>> ? 795 ? ? ? ? ? ? ? ? ?return IRQ_NONE;
>> ? 796
>> ? 797 ? ? ? ? ?/* Dynamic loading TLB or PTE */
>> ? 798 ? ? ? ? ?if (obj->isr)
>> ? 799 ? ? ? ? ? ? ? ? ?err = obj->isr(obj);
>> ? 800
>> ? 801 ? ? ? ? ?if (!err)
>> ? 802 ? ? ? ? ? ? ? ? ?return IRQ_HANDLED;
>> ? 803
>> ? 804 ? ? ? ? ?clk_enable(obj->clk);
>> ? 805 ? ? ? ? ?stat = iommu_report_fault(obj, &da);
>> ? 806 ? ? ? ? ?clk_disable(obj->clk);
>> ? 807 ? ? ? ? ?if (!stat)
>> ? 808 ? ? ? ? ? ? ? ? ?return IRQ_HANDLED;
>> ? 809
>> ? 810 ? ? ? ? ?iommu_disable(obj);
>>
>> I guess that this modifying the above code could make (*isr)()
>> flexible to be used for any purpose for clients? For me, having both
>> following may be a bit residual.
>

There are few possible issues in this case. (*isr)() is meant to
replace the generic fault handler on iommu, but the fault callback
isn't. Basically fault callback needs to call specific iommu fault
report to know faulty 'da' and iommu errors, so part of the generic
fault handler must be called.

One possible solution is always call specific fault report before
(*isr)(). IMO it makes sense as (*isr)() might want to know at least
the current faults.
But in this case, specific fault report should not print anything else
as only the upper layer and user will know when a fault is actually an
error or not. So, they're responsible for error messages.

I'm sending a v3 with these changes. Comments will be welcome.

Br,

David

> I agree. We need to add 'void *isr_priv' to iommu struct and the
> function to register isr.
> I'll send a v3 soon.
>
> Regards,
>
> David
>
>>
>>> ? ? ? int (*isr)(struct iommu *obj);
>>> + ? ? void (*fault_cb)(struct iommu *obj, u32 da, u32 iommu_errs, void *priv);
>>
>