[PATCH] clk: tegra: use pll_ref as the pll_e parent

[PATCH] clk: tegra: use pll_ref as the pll_e parent

[Peter De Schrijver]

Use pll_ref instead of pll_re_vco as the pll_e parent on Tegra114 and
Tegra124. Also add a pll_ref table entry for pll_e for Tegra114.

Signed-off-by: Peter De Schrijver <pdeschrijver-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
 drivers/clk/tegra/clk-pll.c      |    7 ++++---
 drivers/clk/tegra/clk-tegra114.c |    3 ++-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c
index 7d775a9..193457b 100644
--- a/drivers/clk/tegra/clk-pll.c
+++ b/drivers/clk/tegra/clk-pll.c
@@ -1712,11 +1712,12 @@ struct clk *tegra_clk_register_plle_tegra114(const char *name,
 	val_aux = pll_readl(pll_params->aux_reg, pll);
 
 	if (val & PLL_BASE_ENABLE) {
-		if (!(val_aux & PLLE_AUX_PLLRE_SEL))
+		if ((val_aux & PLLE_AUX_PLLRE_SEL) || (val_aux & val_aux))
 			WARN(1, "pll_e enabled with unsupported parent %s\n",
-			  (val & PLLE_AUX_PLLP_SEL) ? "pllp_out0" : "pll_ref");
+			  (val_aux & PLLE_AUX_PLLP_SEL) ? "pllp_out0" :
+					"pll_re_vco");
 	} else {
-		val_aux |= PLLE_AUX_PLLRE_SEL;
+		val_aux &= ~(PLLE_AUX_PLLRE_SEL | PLLE_AUX_PLLP_SEL);
 		pll_writel(val, pll_params->aux_reg, pll);
 	}
 
diff --git a/drivers/clk/tegra/clk-tegra114.c b/drivers/clk/tegra/clk-tegra114.c
index e365b35..5cfcd3e 100644
--- a/drivers/clk/tegra/clk-tegra114.c
+++ b/drivers/clk/tegra/clk-tegra114.c
@@ -560,6 +560,7 @@ static struct tegra_clk_pll_freq_table pll_e_freq_table[] = {
 	/* PLLE special case: use cpcon field to store cml divider value */
 	{336000000, 100000000, 100, 21, 16, 11},
 	{312000000, 100000000, 200, 26, 24, 13},
+	{12000000, 100000000, 200,  1,  24, 13},
 	{0, 0, 0, 0, 0, 0},
 };
 
@@ -1178,7 +1179,7 @@ static void __init tegra114_pll_init(void __iomem *clk_base,
 	clks[TEGRA114_CLK_PLL_RE_OUT] = clk;
 
 	/* PLLE */
-	clk = tegra_clk_register_plle_tegra114("pll_e_out0", "pll_re_vco",
+	clk = tegra_clk_register_plle_tegra114("pll_e_out0", "pll_ref",
 				      clk_base, 0, &pll_e_params, NULL);
 	clks[TEGRA114_CLK_PLL_E_OUT0] = clk;
 }
-- 
1.7.7.rc0.72.g4b5ea.dirty

Re: [PATCH] clk: tegra: use pll_ref as the pll_e parent

[Stephen Warren]

On 10/29/2013 06:41 PM, Peter De Schrijver wrote:
> Use pll_ref instead of pll_re_vco as the pll_e parent on Tegra114 and
> Tegra124. Also add a pll_ref table entry for pll_e for Tegra114.

Why? What benefit does this give, or what bug does this fix?

> diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c

>  	val_aux = pll_readl(pll_params->aux_reg, pll);
>  
>  	if (val & PLL_BASE_ENABLE) {
> -		if (!(val_aux & PLLE_AUX_PLLRE_SEL))
> +		if ((val_aux & PLLE_AUX_PLLRE_SEL) || (val_aux & val_aux))

Isn't "|| (val_aux & val_aux)" always true, at least if the value is
non-zero? Either this should be simply "|| val_aux", or one of those two
"val_aux" is the wrong thing.

>  			WARN(1, "pll_e enabled with unsupported parent %s\n",
> -			  (val & PLLE_AUX_PLLP_SEL) ? "pllp_out0" : "pll_ref");
> +			  (val_aux & PLLE_AUX_PLLP_SEL) ? "pllp_out0" :
> +					"pll_re_vco");
>  	} else {
> -		val_aux |= PLLE_AUX_PLLRE_SEL;
> +		val_aux &= ~(PLLE_AUX_PLLRE_SEL | PLLE_AUX_PLLP_SEL);
>  		pll_writel(val, pll_params->aux_reg, pll);
>  	}

> diff --git a/drivers/clk/tegra/clk-tegra114.c b/drivers/clk/tegra/clk-tegra114.c

> @@ -560,6 +560,7 @@ static struct tegra_clk_pll_freq_table pll_e_freq_table[] = {
>  	/* PLLE special case: use cpcon field to store cml divider value */
>  	{336000000, 100000000, 100, 21, 16, 11},
>  	{312000000, 100000000, 200, 26, 24, 13},
> +	{12000000, 100000000, 200,  1,  24, 13},

Presumably this is because pll_ref is the crystal, which runs at 12MHz.
What if it doesn't; Tegra supports a bunch of other crystal rates. Don't
we need entries for all the other potential crystal rates too?

Re: [PATCH] clk: tegra: use pll_ref as the pll_e parent

[Lucas Stach]

Am Mittwoch, den 30.10.2013, 09:41 -0600 schrieb Stephen Warren:
> On 10/29/2013 06:41 PM, Peter De Schrijver wrote:
> > Use pll_ref instead of pll_re_vco as the pll_e parent on Tegra114 and
> > Tegra124. Also add a pll_ref table entry for pll_e for Tegra114.
> 
> Why? What benefit does this give, or what bug does this fix?
> 
> > diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c
> 
> >  	val_aux = pll_readl(pll_params->aux_reg, pll);
> >  
> >  	if (val & PLL_BASE_ENABLE) {
> > -		if (!(val_aux & PLLE_AUX_PLLRE_SEL))
> > +		if ((val_aux & PLLE_AUX_PLLRE_SEL) || (val_aux & val_aux))
> 
> Isn't "|| (val_aux & val_aux)" always true, at least if the value is
> non-zero? Either this should be simply "|| val_aux", or one of those two
> "val_aux" is the wrong thing.
> 
> >  			WARN(1, "pll_e enabled with unsupported parent %s\n",
> > -			  (val & PLLE_AUX_PLLP_SEL) ? "pllp_out0" : "pll_ref");
> > +			  (val_aux & PLLE_AUX_PLLP_SEL) ? "pllp_out0" :
> > +					"pll_re_vco");
> >  	} else {
> > -		val_aux |= PLLE_AUX_PLLRE_SEL;
> > +		val_aux &= ~(PLLE_AUX_PLLRE_SEL | PLLE_AUX_PLLP_SEL);
> >  		pll_writel(val, pll_params->aux_reg, pll);
> >  	}
> 
> > diff --git a/drivers/clk/tegra/clk-tegra114.c b/drivers/clk/tegra/clk-tegra114.c
> 
> > @@ -560,6 +560,7 @@ static struct tegra_clk_pll_freq_table pll_e_freq_table[] = {
> >  	/* PLLE special case: use cpcon field to store cml divider value */
> >  	{336000000, 100000000, 100, 21, 16, 11},
> >  	{312000000, 100000000, 200, 26, 24, 13},
> > +	{12000000, 100000000, 200,  1,  24, 13},
> 
> Presumably this is because pll_ref is the crystal, which runs at 12MHz.
> What if it doesn't; Tegra supports a bunch of other crystal rates. Don't
> we need entries for all the other potential crystal rates too?

The TRM states that PCIe and thus PLLE are only supported with 12MHz
external crystal rate.

-- 
Pengutronix e.K.                           | Lucas Stach                 |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-5076 |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCH] clk: tegra: use pll_ref as the pll_e parent

[Peter De Schrijver]

On Wed, Oct 30, 2013 at 04:44:10PM +0100, Lucas Stach wrote:
> Am Mittwoch, den 30.10.2013, 09:41 -0600 schrieb Stephen Warren:
> > On 10/29/2013 06:41 PM, Peter De Schrijver wrote:
> > > Use pll_ref instead of pll_re_vco as the pll_e parent on Tegra114 and
> > > Tegra124. Also add a pll_ref table entry for pll_e for Tegra114.
> > 
> > Why? What benefit does this give, or what bug does this fix?
> > 
> > > diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c
> > 
> > >  	val_aux = pll_readl(pll_params->aux_reg, pll);
> > >  
> > >  	if (val & PLL_BASE_ENABLE) {
> > > -		if (!(val_aux & PLLE_AUX_PLLRE_SEL))
> > > +		if ((val_aux & PLLE_AUX_PLLRE_SEL) || (val_aux & val_aux))
> > 
> > Isn't "|| (val_aux & val_aux)" always true, at least if the value is
> > non-zero? Either this should be simply "|| val_aux", or one of those two
> > "val_aux" is the wrong thing.
> > 
> > >  			WARN(1, "pll_e enabled with unsupported parent %s\n",
> > > -			  (val & PLLE_AUX_PLLP_SEL) ? "pllp_out0" : "pll_ref");
> > > +			  (val_aux & PLLE_AUX_PLLP_SEL) ? "pllp_out0" :
> > > +					"pll_re_vco");
> > >  	} else {
> > > -		val_aux |= PLLE_AUX_PLLRE_SEL;
> > > +		val_aux &= ~(PLLE_AUX_PLLRE_SEL | PLLE_AUX_PLLP_SEL);
> > >  		pll_writel(val, pll_params->aux_reg, pll);
> > >  	}
> > 
> > > diff --git a/drivers/clk/tegra/clk-tegra114.c b/drivers/clk/tegra/clk-tegra114.c
> > 
> > > @@ -560,6 +560,7 @@ static struct tegra_clk_pll_freq_table pll_e_freq_table[] = {
> > >  	/* PLLE special case: use cpcon field to store cml divider value */
> > >  	{336000000, 100000000, 100, 21, 16, 11},
> > >  	{312000000, 100000000, 200, 26, 24, 13},
> > > +	{12000000, 100000000, 200,  1,  24, 13},
> > 
> > Presumably this is because pll_ref is the crystal, which runs at 12MHz.
> > What if it doesn't; Tegra supports a bunch of other crystal rates. Don't
> > we need entries for all the other potential crystal rates too?
> 
> The TRM states that PCIe and thus PLLE are only supported with 12MHz
> external crystal rate.
> 

This is has been different for Tegra114 at least (where PLLE is used for USB3)

Cheers,

Peter.

Re: [PATCH] clk: tegra: use pll_ref as the pll_e parent

[Peter De Schrijver]

On Wed, Oct 30, 2013 at 04:41:41PM +0100, Stephen Warren wrote:
> On 10/29/2013 06:41 PM, Peter De Schrijver wrote:
> > Use pll_ref instead of pll_re_vco as the pll_e parent on Tegra114 and
> > Tegra124. Also add a pll_ref table entry for pll_e for Tegra114.
> 
> Why? What benefit does this give, or what bug does this fix?
> 

Otherrwise Tegra114 will crash on boot.

> > diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c
> 
> >  	val_aux = pll_readl(pll_params->aux_reg, pll);
> >  
> >  	if (val & PLL_BASE_ENABLE) {
> > -		if (!(val_aux & PLLE_AUX_PLLRE_SEL))
> > +		if ((val_aux & PLLE_AUX_PLLRE_SEL) || (val_aux & val_aux))
> 
> Isn't "|| (val_aux & val_aux)" always true, at least if the value is
> non-zero? Either this should be simply "|| val_aux", or one of those two
> "val_aux" is the wrong thing.
> 

It should have been val_aux & PLLE_AUX_PLLP_SEL...

Cheers,

Peter.

Re: [PATCH] clk: tegra: use pll_ref as the pll_e parent

[Stephen Warren]

On 10/30/2013 04:18 PM, Peter De Schrijver wrote:
> On Wed, Oct 30, 2013 at 04:41:41PM +0100, Stephen Warren wrote:
>> On 10/29/2013 06:41 PM, Peter De Schrijver wrote:
>>> Use pll_ref instead of pll_re_vco as the pll_e parent on Tegra114 and
>>> Tegra124. Also add a pll_ref table entry for pll_e for Tegra114.
>>
>> Why? What benefit does this give, or what bug does this fix?
> 
> Otherrwise Tegra114 will crash on boot.

Sigh. For what reason?

Re: [PATCH] clk: tegra: use pll_ref as the pll_e parent

[Peter De Schrijver]

On Wed, Oct 30, 2013 at 11:50:03PM +0100, Stephen Warren wrote:
> On 10/30/2013 04:18 PM, Peter De Schrijver wrote:
> > On Wed, Oct 30, 2013 at 04:41:41PM +0100, Stephen Warren wrote:
> >> On 10/29/2013 06:41 PM, Peter De Schrijver wrote:
> >>> Use pll_ref instead of pll_re_vco as the pll_e parent on Tegra114 and
> >>> Tegra124. Also add a pll_ref table entry for pll_e for Tegra114.
> >>
> >> Why? What benefit does this give, or what bug does this fix?
> > 
> > Otherrwise Tegra114 will crash on boot.
> 
> Sigh. For what reason?

pll_re_vco having an unsupported rate of 300Mhz. My guess is that it depends
on the bootloader if you will see this. I'm fairly sure I verified this on
my dalmore in helsinki and it worked, but it failed on Paul's test setup.

Cheers,

Peter.

Re: [PATCH] clk: tegra: use pll_ref as the pll_e parent

[Stephen Warren]

On 10/31/2013 09:41 AM, Peter De Schrijver wrote:
> On Wed, Oct 30, 2013 at 11:50:03PM +0100, Stephen Warren wrote:
>> On 10/30/2013 04:18 PM, Peter De Schrijver wrote:
>>> On Wed, Oct 30, 2013 at 04:41:41PM +0100, Stephen Warren wrote:
>>>> On 10/29/2013 06:41 PM, Peter De Schrijver wrote:
>>>>> Use pll_ref instead of pll_re_vco as the pll_e parent on Tegra114 and
>>>>> Tegra124. Also add a pll_ref table entry for pll_e for Tegra114.
>>>>
>>>> Why? What benefit does this give, or what bug does this fix?
>>>
>>> Otherrwise Tegra114 will crash on boot.
>>
>> Sigh. For what reason?
> 
> pll_re_vco having an unsupported rate of 300Mhz. My guess is that it depends
> on the bootloader if you will see this. I'm fairly sure I verified this on
> my dalmore in helsinki and it worked, but it failed on Paul's test setup.

OK, so this is primarily a SW issue, because pll_e's freq_table simply
doesn't have an entry for input frequency 300MHz. Can you make sure the
commit description explains that?

Re: [PATCH] clk: tegra: use pll_ref as the pll_e parent

[Peter De Schrijver]

On Wed, Oct 30, 2013 at 01:41:29AM +0100, Peter De Schrijver wrote:
> Use pll_ref instead of pll_re_vco as the pll_e parent on Tegra114 and
> Tegra124. Also add a pll_ref table entry for pll_e for Tegra114.
> 
> Signed-off-by: Peter De Schrijver <pdeschrijver-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

I will squash this into the next tegra-clk-next as the previous pull request
has never made it.

Cheers,

Peter.

Re: [PATCH] clk: tegra: use pll_ref as the pll_e parent

[Peter De Schrijver]

On Fri, Nov 22, 2013 at 02:40:35PM +0100, Peter De Schrijver wrote:
> On Wed, Oct 30, 2013 at 01:41:29AM +0100, Peter De Schrijver wrote:
> > Use pll_ref instead of pll_re_vco as the pll_e parent on Tegra114 and
> > Tegra124. Also add a pll_ref table entry for pll_e for Tegra114.
> > 
> > Signed-off-by: Peter De Schrijver <pdeschrijver-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> 
> I will squash this into the next tegra-clk-next as the previous pull request
> has never made it.
> 

Looking again at this, I think the Tegra114 and generic PLL part of the patch
better stays as a separate patch. The Tegra124 bit will be squashed into the
Tegra124 support patch.

Cheers,

Peter.