[PATCH] IOMMU: arm-smmu-v3: Use STE.S1STALLD only when supported

[PATCH] IOMMU: arm-smmu-v3: Use STE.S1STALLD only when supported

[pmallapp]

From: Prem Mallappa <pmallapp@broadcom.com>

Also fix the STALLD check.

Signed-off-by: Prem Mallappa <pmallapp@broadcom.com>
---
 drivers/iommu/arm-smmu-v3.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index ed409cb..804671c 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -38,7 +38,9 @@
 #define IDR0_ST_LVL_SHIFT		27
 #define IDR0_ST_LVL_MASK		0x3
 #define IDR0_ST_LVL_2LVL		(1 << IDR0_ST_LVL_SHIFT)
-#define IDR0_STALL_MODEL		(3 << 24)
+#define IDR0_STALL_SHIFT		24
+#define IDR0_STALL_MODEL_STALL		0x0
+#define IDR0_STALL_MODEL_FORCE		0x2
 #define IDR0_TTENDIAN_SHIFT		21
 #define IDR0_TTENDIAN_MASK		0x3
 #define IDR0_TTENDIAN_LE		(2 << IDR0_TTENDIAN_SHIFT)
@@ -1051,12 +1053,14 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid,
 			 STRTAB_STE_1_S1C_CACHE_WBRA
 			 << STRTAB_STE_1_S1COR_SHIFT |
 			 STRTAB_STE_1_S1C_SH_ISH << STRTAB_STE_1_S1CSH_SHIFT |
-			 STRTAB_STE_1_S1STALLD |
 #ifdef CONFIG_PCI_ATS
 			 STRTAB_STE_1_EATS_TRANS << STRTAB_STE_1_EATS_SHIFT |
 #endif
 			 STRTAB_STE_1_STRW_NSEL1 << STRTAB_STE_1_STRW_SHIFT);
 
+		if (smmu->features & ARM_SMMU_FEAT_STALLS)
+			dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);
+
 		val |= (ste->s1_cfg->cdptr_dma & STRTAB_STE_0_S1CTXPTR_MASK
 		        << STRTAB_STE_0_S1CTXPTR_SHIFT) |
 			STRTAB_STE_0_CFG_S1_TRANS;
@@ -2483,8 +2487,14 @@ static int arm_smmu_device_probe(struct arm_smmu_device *smmu)
 		dev_warn(smmu->dev, "IDR0.COHACC overridden by dma-coherent property (%s)\n",
 			 coherent ? "true" : "false");
 
-	if (reg & IDR0_STALL_MODEL)
+	switch ((reg >> IDR0_STALL_SHIFT) & 0x3) {
+	case IDR0_STALL_MODEL_STALL:
+	case IDR0_STALL_MODEL_FORCE:
 		smmu->features |= ARM_SMMU_FEAT_STALLS;
+		break;
+	default:
+		break;
+	}
 
 	if (reg & IDR0_S1P)
 		smmu->features |= ARM_SMMU_FEAT_TRANS_S1;
-- 
2.6.0

Re: [PATCH] IOMMU: arm-smmu-v3: Use STE.S1STALLD only when supported

[Will Deacon]

Hi Prem,

Thanks for the patch. Just a few minor comments...

On Mon, Nov 16, 2015 at 02:18:20PM +0530, pmallapp-dY08KVG/lbpWk0Htik3J/w@public.gmane.org wrote:
> From: Prem Mallappa <pmallapp-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> 
> Also fix the STALLD check.

Can you extend the commit message please to explain that it is ILLEGAL
to set STE.S1STALLD to 1 if stage 1 is enabled and either the stall or
terminate models are not supported?

> Signed-off-by: Prem Mallappa <pmallapp-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> ---
>  drivers/iommu/arm-smmu-v3.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index ed409cb..804671c 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -38,7 +38,9 @@
>  #define IDR0_ST_LVL_SHIFT		27
>  #define IDR0_ST_LVL_MASK		0x3
>  #define IDR0_ST_LVL_2LVL		(1 << IDR0_ST_LVL_SHIFT)
> -#define IDR0_STALL_MODEL		(3 << 24)
> +#define IDR0_STALL_SHIFT		24

To keep the style consistent, can you also add IDR0_STALL_MASK please...

> +#define IDR0_STALL_MODEL_STALL		0x0
> +#define IDR0_STALL_MODEL_FORCE		0x2

... and shift these guys left by IDR0_STALL_SHIFT?

>
>  #define IDR0_TTENDIAN_SHIFT		21
>  #define IDR0_TTENDIAN_MASK		0x3
>  #define IDR0_TTENDIAN_LE		(2 << IDR0_TTENDIAN_SHIFT)
> @@ -1051,12 +1053,14 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid,
>  			 STRTAB_STE_1_S1C_CACHE_WBRA
>  			 << STRTAB_STE_1_S1COR_SHIFT |
>  			 STRTAB_STE_1_S1C_SH_ISH << STRTAB_STE_1_S1CSH_SHIFT |
> -			 STRTAB_STE_1_S1STALLD |
>  #ifdef CONFIG_PCI_ATS
>  			 STRTAB_STE_1_EATS_TRANS << STRTAB_STE_1_EATS_SHIFT |
>  #endif
>  			 STRTAB_STE_1_STRW_NSEL1 << STRTAB_STE_1_STRW_SHIFT);
>  
> +		if (smmu->features & ARM_SMMU_FEAT_STALLS)
> +			dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);
> +
>  		val |= (ste->s1_cfg->cdptr_dma & STRTAB_STE_0_S1CTXPTR_MASK
>  		        << STRTAB_STE_0_S1CTXPTR_SHIFT) |
>  			STRTAB_STE_0_CFG_S1_TRANS;
> @@ -2483,8 +2487,14 @@ static int arm_smmu_device_probe(struct arm_smmu_device *smmu)
>  		dev_warn(smmu->dev, "IDR0.COHACC overridden by dma-coherent property (%s)\n",
>  			 coherent ? "true" : "false");
>  
> -	if (reg & IDR0_STALL_MODEL)
> +	switch ((reg >> IDR0_STALL_SHIFT) & 0x3) {

Then structure this more like the TTENDIAN code:

  switch (reg & IDR0_STALL_MASK << IDR0_STALL_SHIFT) {

> +	case IDR0_STALL_MODEL_STALL:
> +	case IDR0_STALL_MODEL_FORCE:
>  		smmu->features |= ARM_SMMU_FEAT_STALLS;
> +		break;
> +	default:
> +		break;
> +	}

I think you can drop the default case, or does GCC complain?

Will

RE: [PATCH] IOMMU: arm-smmu-v3: Use STE.S1STALLD only when supported

[Prem (Premachandra) Mallappa]

> -----Original Message-----
> From: Will Deacon [mailto:will.deacon@arm.com]
> Sent: 17 November 2015 11:17 PM
> To: Prem (Premachandra) Mallappa
> Cc: iommu@lists.linux-foundation.org; linux-arm-kernel@lists.infradead.org;
> Jayachandran Chandrashekaran Nair
> Subject: Re: [PATCH] IOMMU: arm-smmu-v3: Use STE.S1STALLD only when
> supported
> 
> Hi Prem,
> 
> Thanks for the patch. Just a few minor comments...
> 
> On Mon, Nov 16, 2015 at 02:18:20PM +0530, pmallapp@broadcom.com
> wrote:
> > From: Prem Mallappa <pmallapp@broadcom.com>
> >
> > Also fix the STALLD check.
> 
> Can you extend the commit message please to explain that it is ILLEGAL to
> set STE.S1STALLD to 1 if stage 1 is enabled and either the stall or terminate
> models are not supported?
> 
> > Signed-off-by: Prem Mallappa <pmallapp@broadcom.com>
> > ---
> >  drivers/iommu/arm-smmu-v3.c | 16 +++++++++++++---
> >  1 file changed, 13 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-
> v3.c
> > index ed409cb..804671c 100644
> > --- a/drivers/iommu/arm-smmu-v3.c
> > +++ b/drivers/iommu/arm-smmu-v3.c
> > @@ -38,7 +38,9 @@
> >  #define IDR0_ST_LVL_SHIFT		27
> >  #define IDR0_ST_LVL_MASK		0x3
> >  #define IDR0_ST_LVL_2LVL		(1 << IDR0_ST_LVL_SHIFT)
> > -#define IDR0_STALL_MODEL		(3 << 24)
> > +#define IDR0_STALL_SHIFT		24
> 
> To keep the style consistent, can you also add IDR0_STALL_MASK please...
> 
> > +#define IDR0_STALL_MODEL_STALL		0x0
> > +#define IDR0_STALL_MODEL_FORCE		0x2
> 
> ... and shift these guys left by IDR0_STALL_SHIFT?
> 
> >
> >  #define IDR0_TTENDIAN_SHIFT		21
> >  #define IDR0_TTENDIAN_MASK		0x3
> >  #define IDR0_TTENDIAN_LE		(2 << IDR0_TTENDIAN_SHIFT)
> > @@ -1051,12 +1053,14 @@ static void arm_smmu_write_strtab_ent(struct
> arm_smmu_device *smmu, u32 sid,
> >  			 STRTAB_STE_1_S1C_CACHE_WBRA
> >  			 << STRTAB_STE_1_S1COR_SHIFT |
> >  			 STRTAB_STE_1_S1C_SH_ISH <<
> STRTAB_STE_1_S1CSH_SHIFT |
> > -			 STRTAB_STE_1_S1STALLD |
> >  #ifdef CONFIG_PCI_ATS
> >  			 STRTAB_STE_1_EATS_TRANS <<
> STRTAB_STE_1_EATS_SHIFT |  #endif
> >  			 STRTAB_STE_1_STRW_NSEL1 <<
> STRTAB_STE_1_STRW_SHIFT);
> >
> > +		if (smmu->features & ARM_SMMU_FEAT_STALLS)
> > +			dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);
> > +
> >  		val |= (ste->s1_cfg->cdptr_dma &
> STRTAB_STE_0_S1CTXPTR_MASK
> >  		        << STRTAB_STE_0_S1CTXPTR_SHIFT) |
> >  			STRTAB_STE_0_CFG_S1_TRANS;
> > @@ -2483,8 +2487,14 @@ static int arm_smmu_device_probe(struct
> arm_smmu_device *smmu)
> >  		dev_warn(smmu->dev, "IDR0.COHACC overridden by dma-
> coherent property (%s)\n",
> >  			 coherent ? "true" : "false");
> >
> > -	if (reg & IDR0_STALL_MODEL)
> > +	switch ((reg >> IDR0_STALL_SHIFT) & 0x3) {
> 
> Then structure this more like the TTENDIAN code:
> 
>   switch (reg & IDR0_STALL_MASK << IDR0_STALL_SHIFT) {
> 
> > +	case IDR0_STALL_MODEL_STALL:
> > +	case IDR0_STALL_MODEL_FORCE:
> >  		smmu->features |= ARM_SMMU_FEAT_STALLS;
> > +		break;
> > +	default:
> > +		break;
> > +	}
> 
> I think you can drop the default case, or does GCC complain?
> 
> Will


Thanks for comments, I was on holiday, I'll send updated patch along with 2 more soon.

/Prem

Re: [PATCH] IOMMU: arm-smmu-v3: Use STE.S1STALLD only when supported

[Will Deacon]

Hi Prem,

On Tue, Nov 24, 2015 at 05:30:37AM +0000, Prem (Premachandra) Mallappa wrote:
> Thanks for comments, I was on holiday, I'll send updated patch along with
> 2 more soon.

Any update on this patch?

Cheers,

Will

RE: [PATCH] IOMMU: arm-smmu-v3: Use STE.S1STALLD only when supported

[Prem (Premachandra) Mallappa]

Hi Will,
It is ready, in internal review, will be sending it in a day.

/Prem

> -----Original Message-----
> From: Will Deacon [mailto:will.deacon-5wv7dgnIgG8@public.gmane.org]
> Sent: 12 December 2015 01:23 AM
> To: Prem (Premachandra) Mallappa
> Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org; linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org;
> Jayachandran Chandrashekaran Nair
> Subject: Re: [PATCH] IOMMU: arm-smmu-v3: Use STE.S1STALLD only when
> supported
> 
> Hi Prem,
> 
> On Tue, Nov 24, 2015 at 05:30:37AM +0000, Prem (Premachandra) Mallappa
> wrote:
> > Thanks for comments, I was on holiday, I'll send updated patch along with
> > 2 more soon.
> 
> Any update on this patch?
> 
> Cheers,
> 
> Will