[PATCH] iommu/qcom: add optional clock for TLB invalidate

[PATCH] iommu/qcom: add optional clock for TLB invalidate

[Shawn Guo]

On some SoCs like MSM8939 with A405 adreno, there is a gfx_tbu clock
needs to be on while doing TLB invalidate. Otherwise, TLBSYNC status
will not be correctly reflected, causing the system to go into a bad
state.  Add it as an optional clock, so that platforms that have this
clock can pass it over DT.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
---
 drivers/iommu/qcom_iommu.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/iommu/qcom_iommu.c b/drivers/iommu/qcom_iommu.c
index 0e2a96467767..2f6c6da7d540 100644
--- a/drivers/iommu/qcom_iommu.c
+++ b/drivers/iommu/qcom_iommu.c
@@ -45,6 +45,7 @@ struct qcom_iommu_dev {
 	struct device		*dev;
 	struct clk		*iface_clk;
 	struct clk		*bus_clk;
+	struct clk		*tlb_clk;
 	void __iomem		*local_base;
 	u32			 sec_id;
 	u8			 num_ctxs;
@@ -643,11 +644,20 @@ static int qcom_iommu_enable_clocks(struct qcom_iommu_dev *qcom_iommu)
 		return ret;
 	}
 
+	ret = clk_prepare_enable(qcom_iommu->tlb_clk);
+	if (ret) {
+		dev_err(qcom_iommu->dev, "Couldn't enable tlb_clk\n");
+		clk_disable_unprepare(qcom_iommu->bus_clk);
+		clk_disable_unprepare(qcom_iommu->iface_clk);
+		return ret;
+	}
+
 	return 0;
 }
 
 static void qcom_iommu_disable_clocks(struct qcom_iommu_dev *qcom_iommu)
 {
+	clk_disable_unprepare(qcom_iommu->tlb_clk);
 	clk_disable_unprepare(qcom_iommu->bus_clk);
 	clk_disable_unprepare(qcom_iommu->iface_clk);
 }
@@ -839,6 +849,12 @@ static int qcom_iommu_device_probe(struct platform_device *pdev)
 		return PTR_ERR(qcom_iommu->bus_clk);
 	}
 
+	qcom_iommu->tlb_clk = devm_clk_get(dev, "tlb");
+	if (IS_ERR(qcom_iommu->tlb_clk)) {
+		dev_dbg(dev, "failed to get tlb clock\n");
+		qcom_iommu->tlb_clk = NULL;
+	}
+
 	if (of_property_read_u32(dev->of_node, "qcom,iommu-secure-id",
 				 &qcom_iommu->sec_id)) {
 		dev_err(dev, "missing qcom,iommu-secure-id property\n");
-- 
2.17.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH] iommu/qcom: add optional clock for TLB invalidate

[Stanimir Varbanov]

Hi Shawn,

On 5/9/20 4:08 PM, Shawn Guo wrote:
> On some SoCs like MSM8939 with A405 adreno, there is a gfx_tbu clock
> needs to be on while doing TLB invalidate. Otherwise, TLBSYNC status
> will not be correctly reflected, causing the system to go into a bad
> state.  Add it as an optional clock, so that platforms that have this
> clock can pass it over DT.
> 
> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
> ---
>  drivers/iommu/qcom_iommu.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/iommu/qcom_iommu.c b/drivers/iommu/qcom_iommu.c
> index 0e2a96467767..2f6c6da7d540 100644
> --- a/drivers/iommu/qcom_iommu.c
> +++ b/drivers/iommu/qcom_iommu.c
> @@ -45,6 +45,7 @@ struct qcom_iommu_dev {
>  	struct device		*dev;
>  	struct clk		*iface_clk;
>  	struct clk		*bus_clk;
> +	struct clk		*tlb_clk;
>  	void __iomem		*local_base;
>  	u32			 sec_id;
>  	u8			 num_ctxs;
> @@ -643,11 +644,20 @@ static int qcom_iommu_enable_clocks(struct qcom_iommu_dev *qcom_iommu)
>  		return ret;
>  	}
>  
> +	ret = clk_prepare_enable(qcom_iommu->tlb_clk);
> +	if (ret) {
> +		dev_err(qcom_iommu->dev, "Couldn't enable tlb_clk\n");
> +		clk_disable_unprepare(qcom_iommu->bus_clk);
> +		clk_disable_unprepare(qcom_iommu->iface_clk);
> +		return ret;
> +	}
> +
>  	return 0;
>  }
>  
>  static void qcom_iommu_disable_clocks(struct qcom_iommu_dev *qcom_iommu)
>  {
> +	clk_disable_unprepare(qcom_iommu->tlb_clk);
>  	clk_disable_unprepare(qcom_iommu->bus_clk);
>  	clk_disable_unprepare(qcom_iommu->iface_clk);
>  }
> @@ -839,6 +849,12 @@ static int qcom_iommu_device_probe(struct platform_device *pdev)
>  		return PTR_ERR(qcom_iommu->bus_clk);
>  	}
>  
> +	qcom_iommu->tlb_clk = devm_clk_get(dev, "tlb");

IMO, devm_clk_get_optional() would be better.

> +	if (IS_ERR(qcom_iommu->tlb_clk)) {
> +		dev_dbg(dev, "failed to get tlb clock\n");
> +		qcom_iommu->tlb_clk = NULL;
> +	}
> +
>  	if (of_property_read_u32(dev->of_node, "qcom,iommu-secure-id",
>  				 &qcom_iommu->sec_id)) {
>  		dev_err(dev, "missing qcom,iommu-secure-id property\n");
> 

-- 
regards,
Stan
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH] iommu/qcom: add optional clock for TLB invalidate

[Shawn Guo]

Hi Stanimir,

On Sat, May 09, 2020 at 04:21:20PM +0300, Stanimir Varbanov wrote:
...
> > @@ -839,6 +849,12 @@ static int qcom_iommu_device_probe(struct platform_device *pdev)
> >  		return PTR_ERR(qcom_iommu->bus_clk);
> >  	}
> >  
> > +	qcom_iommu->tlb_clk = devm_clk_get(dev, "tlb");
> 
> IMO, devm_clk_get_optional() would be better.

Yes, indeed.  The function will make it clear that the clock is
an optional one.  I will make the change in v2.

Thanks for the comment!

Shawn
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH] iommu/qcom: add optional clock for TLB invalidate

[Bjorn Andersson]

On Sat 09 May 06:08 PDT 2020, Shawn Guo wrote:

> On some SoCs like MSM8939 with A405 adreno, there is a gfx_tbu clock
> needs to be on while doing TLB invalidate. Otherwise, TLBSYNC status
> will not be correctly reflected, causing the system to go into a bad
> state.  Add it as an optional clock, so that platforms that have this
> clock can pass it over DT.
> 
> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
> ---
>  drivers/iommu/qcom_iommu.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/iommu/qcom_iommu.c b/drivers/iommu/qcom_iommu.c
> index 0e2a96467767..2f6c6da7d540 100644
> --- a/drivers/iommu/qcom_iommu.c
> +++ b/drivers/iommu/qcom_iommu.c
> @@ -45,6 +45,7 @@ struct qcom_iommu_dev {
>  	struct device		*dev;
>  	struct clk		*iface_clk;
>  	struct clk		*bus_clk;
> +	struct clk		*tlb_clk;
>  	void __iomem		*local_base;
>  	u32			 sec_id;
>  	u8			 num_ctxs;
> @@ -643,11 +644,20 @@ static int qcom_iommu_enable_clocks(struct qcom_iommu_dev *qcom_iommu)
>  		return ret;
>  	}
>  
> +	ret = clk_prepare_enable(qcom_iommu->tlb_clk);
> +	if (ret) {
> +		dev_err(qcom_iommu->dev, "Couldn't enable tlb_clk\n");
> +		clk_disable_unprepare(qcom_iommu->bus_clk);
> +		clk_disable_unprepare(qcom_iommu->iface_clk);
> +		return ret;
> +	}

Seems this is an excellent opportunity to replace
qcom_iommu_enable_clocks() to clk_bulk_prepare_enable() and disable,
respectively.

> +
>  	return 0;
>  }
>  
>  static void qcom_iommu_disable_clocks(struct qcom_iommu_dev *qcom_iommu)
>  {
> +	clk_disable_unprepare(qcom_iommu->tlb_clk);
>  	clk_disable_unprepare(qcom_iommu->bus_clk);
>  	clk_disable_unprepare(qcom_iommu->iface_clk);
>  }
> @@ -839,6 +849,12 @@ static int qcom_iommu_device_probe(struct platform_device *pdev)
>  		return PTR_ERR(qcom_iommu->bus_clk);
>  	}
>  
> +	qcom_iommu->tlb_clk = devm_clk_get(dev, "tlb");

Wouldn't "tbu" be a better name for this clock? Given that seems the
actually be the hardware block you're clocking.


That said, I thought we used device links and pm_runtime to ensure that
the TBUs are powered and clocked...

Regards,
Bjorn

> +	if (IS_ERR(qcom_iommu->tlb_clk)) {
> +		dev_dbg(dev, "failed to get tlb clock\n");
> +		qcom_iommu->tlb_clk = NULL;
> +	}
> +
>  	if (of_property_read_u32(dev->of_node, "qcom,iommu-secure-id",
>  				 &qcom_iommu->sec_id)) {
>  		dev_err(dev, "missing qcom,iommu-secure-id property\n");
> -- 
> 2.17.1
> 
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH] iommu/qcom: add optional clock for TLB invalidate

[Rob Clark]

On Mon, May 11, 2020 at 10:52 PM Bjorn Andersson
<bjorn.andersson@linaro.org> wrote:
>
> On Sat 09 May 06:08 PDT 2020, Shawn Guo wrote:
>
> > On some SoCs like MSM8939 with A405 adreno, there is a gfx_tbu clock
> > needs to be on while doing TLB invalidate. Otherwise, TLBSYNC status
> > will not be correctly reflected, causing the system to go into a bad
> > state.  Add it as an optional clock, so that platforms that have this
> > clock can pass it over DT.
> >
> > Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

[snip]

> > @@ -839,6 +849,12 @@ static int qcom_iommu_device_probe(struct platform_device *pdev)
> >               return PTR_ERR(qcom_iommu->bus_clk);
> >       }
> >
> > +     qcom_iommu->tlb_clk = devm_clk_get(dev, "tlb");
>
> Wouldn't "tbu" be a better name for this clock? Given that seems the
> actually be the hardware block you're clocking.
>
>
> That said, I thought we used device links and pm_runtime to ensure that
> the TBUs are powered and clocked...
>

please don't rely on device-link for that, buffers can be freed (and
therefore need to be unmapped) at times when the gpu is off.

BR,
-R
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH] iommu/qcom: add optional clock for TLB invalidate

[Shawn Guo]

Hi Bjorn,

On Mon, May 11, 2020 at 10:52:42PM -0700, Bjorn Andersson wrote:
> On Sat 09 May 06:08 PDT 2020, Shawn Guo wrote:
> 
> > On some SoCs like MSM8939 with A405 adreno, there is a gfx_tbu clock
> > needs to be on while doing TLB invalidate. Otherwise, TLBSYNC status
> > will not be correctly reflected, causing the system to go into a bad
> > state.  Add it as an optional clock, so that platforms that have this
> > clock can pass it over DT.
> > 
> > Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
> > ---
> >  drivers/iommu/qcom_iommu.c | 16 ++++++++++++++++
> >  1 file changed, 16 insertions(+)
> > 
> > diff --git a/drivers/iommu/qcom_iommu.c b/drivers/iommu/qcom_iommu.c
> > index 0e2a96467767..2f6c6da7d540 100644
> > --- a/drivers/iommu/qcom_iommu.c
> > +++ b/drivers/iommu/qcom_iommu.c
> > @@ -45,6 +45,7 @@ struct qcom_iommu_dev {
> >  	struct device		*dev;
> >  	struct clk		*iface_clk;
> >  	struct clk		*bus_clk;
> > +	struct clk		*tlb_clk;
> >  	void __iomem		*local_base;
> >  	u32			 sec_id;
> >  	u8			 num_ctxs;
> > @@ -643,11 +644,20 @@ static int qcom_iommu_enable_clocks(struct qcom_iommu_dev *qcom_iommu)
> >  		return ret;
> >  	}
> >  
> > +	ret = clk_prepare_enable(qcom_iommu->tlb_clk);
> > +	if (ret) {
> > +		dev_err(qcom_iommu->dev, "Couldn't enable tlb_clk\n");
> > +		clk_disable_unprepare(qcom_iommu->bus_clk);
> > +		clk_disable_unprepare(qcom_iommu->iface_clk);
> > +		return ret;
> > +	}
> 
> Seems this is an excellent opportunity to replace
> qcom_iommu_enable_clocks() to clk_bulk_prepare_enable() and disable,
> respectively.

So we have two required and one optional clocks.  I guess we don't want
to use clk_bulk_get_optional() to get all of them as optional.  So we
will end up with getting clock with individual call and enabling/disabling
with bulk version.  I'm personally not fond of this mixed style.  But if
you really like this, I can change.

> 
> > +
> >  	return 0;
> >  }
> >  
> >  static void qcom_iommu_disable_clocks(struct qcom_iommu_dev *qcom_iommu)
> >  {
> > +	clk_disable_unprepare(qcom_iommu->tlb_clk);
> >  	clk_disable_unprepare(qcom_iommu->bus_clk);
> >  	clk_disable_unprepare(qcom_iommu->iface_clk);
> >  }
> > @@ -839,6 +849,12 @@ static int qcom_iommu_device_probe(struct platform_device *pdev)
> >  		return PTR_ERR(qcom_iommu->bus_clk);
> >  	}
> >  
> > +	qcom_iommu->tlb_clk = devm_clk_get(dev, "tlb");
> 
> Wouldn't "tbu" be a better name for this clock? Given that seems the
> actually be the hardware block you're clocking.

I was trying to emphasize the function of this clock.  But I agree that
'tbu' is a better name now.  I will change it in v2.

Thanks for the comments.

Shawn
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH] iommu/qcom: add optional clock for TLB invalidate

[Bjorn Andersson]

On Thu 14 May 07:39 PDT 2020, Shawn Guo wrote:

> Hi Bjorn,
> 
> On Mon, May 11, 2020 at 10:52:42PM -0700, Bjorn Andersson wrote:
> > On Sat 09 May 06:08 PDT 2020, Shawn Guo wrote:
> > 
> > > On some SoCs like MSM8939 with A405 adreno, there is a gfx_tbu clock
> > > needs to be on while doing TLB invalidate. Otherwise, TLBSYNC status
> > > will not be correctly reflected, causing the system to go into a bad
> > > state.  Add it as an optional clock, so that platforms that have this
> > > clock can pass it over DT.
> > > 
> > > Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
> > > ---
> > >  drivers/iommu/qcom_iommu.c | 16 ++++++++++++++++
> > >  1 file changed, 16 insertions(+)
> > > 
> > > diff --git a/drivers/iommu/qcom_iommu.c b/drivers/iommu/qcom_iommu.c
> > > index 0e2a96467767..2f6c6da7d540 100644
> > > --- a/drivers/iommu/qcom_iommu.c
> > > +++ b/drivers/iommu/qcom_iommu.c
> > > @@ -45,6 +45,7 @@ struct qcom_iommu_dev {
> > >  	struct device		*dev;
> > >  	struct clk		*iface_clk;
> > >  	struct clk		*bus_clk;
> > > +	struct clk		*tlb_clk;
> > >  	void __iomem		*local_base;
> > >  	u32			 sec_id;
> > >  	u8			 num_ctxs;
> > > @@ -643,11 +644,20 @@ static int qcom_iommu_enable_clocks(struct qcom_iommu_dev *qcom_iommu)
> > >  		return ret;
> > >  	}
> > >  
> > > +	ret = clk_prepare_enable(qcom_iommu->tlb_clk);
> > > +	if (ret) {
> > > +		dev_err(qcom_iommu->dev, "Couldn't enable tlb_clk\n");
> > > +		clk_disable_unprepare(qcom_iommu->bus_clk);
> > > +		clk_disable_unprepare(qcom_iommu->iface_clk);
> > > +		return ret;
> > > +	}
> > 
> > Seems this is an excellent opportunity to replace
> > qcom_iommu_enable_clocks() to clk_bulk_prepare_enable() and disable,
> > respectively.
> 
> So we have two required and one optional clocks.  I guess we don't want
> to use clk_bulk_get_optional() to get all of them as optional.  So we
> will end up with getting clock with individual call and enabling/disabling
> with bulk version.  I'm personally not fond of this mixed style.  But if
> you really like this, I can change.
> 

I share your dislike for mixing them, but I do prefer it over the nasty
error handling we end up with in qcom_iommu_enable_clocks().

Regards,
Bjorn

> > 
> > > +
> > >  	return 0;
> > >  }
> > >  
> > >  static void qcom_iommu_disable_clocks(struct qcom_iommu_dev *qcom_iommu)
> > >  {
> > > +	clk_disable_unprepare(qcom_iommu->tlb_clk);
> > >  	clk_disable_unprepare(qcom_iommu->bus_clk);
> > >  	clk_disable_unprepare(qcom_iommu->iface_clk);
> > >  }
> > > @@ -839,6 +849,12 @@ static int qcom_iommu_device_probe(struct platform_device *pdev)
> > >  		return PTR_ERR(qcom_iommu->bus_clk);
> > >  	}
> > >  
> > > +	qcom_iommu->tlb_clk = devm_clk_get(dev, "tlb");
> > 
> > Wouldn't "tbu" be a better name for this clock? Given that seems the
> > actually be the hardware block you're clocking.
> 
> I was trying to emphasize the function of this clock.  But I agree that
> 'tbu' is a better name now.  I will change it in v2.
> 
> Thanks for the comments.
> 
> Shawn
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu