[RFC PATCH] Alternative clk gate ctrl for Kirkwood variants

[RFC PATCH] Alternative clk gate ctrl for Kirkwood variants

[Valentin Longchamp]

This series introduces a clk gate ctrl for the kirkwood variants embedded in the
Prestera SoCs.

This would allow to get rid of the workaround for the km_kirkwood board support
file that was added previously because of the lack of DT clk gate support.

Valentin Longchamp (3):
  clk: mvebu: add gate ctrl for Prestera kirkwood variants
  ARM: kirkwood: look for alternative gate ctrl of node
  ARM: kirkwood: remove clock gating disabling for km_kirkwood

 .../devicetree/bindings/clock/mvebu-gated-clock.txt   | 17 +++++++++++++++++
 arch/arm/boot/dts/kirkwood-98dx4122.dtsi              |  7 +++++++
 arch/arm/mach-kirkwood/board-dt.c                     |  4 ++++
 arch/arm/mach-kirkwood/board-km_kirkwood.c            | 15 ---------------
 drivers/clk/mvebu/clk-gating-ctrl.c                   | 19 +++++++++++++++++++
 5 files changed, 47 insertions(+), 15 deletions(-)

-- 
1.8.0.1

[PATCH 1/3] clk: mvebu: add gate ctrl for Prestera kirkwood variants

[Valentin Longchamp]

The kirkwood device found in the Prestera SoCs does not have all the
peripherals of its the usual kirkwood SoCs. There are hence missing
clocks in the SoCs.

This patch registers another gate controller for the kirkwood that
registers only the available clocks of this kirkwood variant.

Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
---
 .../devicetree/bindings/clock/mvebu-gated-clock.txt   | 17 +++++++++++++++++
 drivers/clk/mvebu/clk-gating-ctrl.c                   | 19 +++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/Documentation/devicetree/bindings/clock/mvebu-gated-clock.txt b/Documentation/devicetree/bindings/clock/mvebu-gated-clock.txt
index cffc93d..7f494e90 100644
--- a/Documentation/devicetree/bindings/clock/mvebu-gated-clock.txt
+++ b/Documentation/devicetree/bindings/clock/mvebu-gated-clock.txt
@@ -92,10 +92,27 @@ ID	Clock	Peripheral
 19	ge1	Gigabit Ethernet 1
 20	tdm	Time Division Mplx
 
+The following is a list of provided IDs for Kirkwood Prestera variant:
+ID	Clock	Peripheral
+-----------------------------------
+0	ge0	Gigabit Ethernet 0
+2	pex0	PCIe Cntrl 0
+3	usb0	USB Host 0
+4	sdio	SDIO Cntrl
+5	tsu	Transp. Stream Unit
+6	dunit	SDRAM Cntrl
+7	runit	Runit
+8	xor0	XOR DMA 0
+16	xor1	XOR DMA 1
+17	crypto	CESA engine
+19	ge1	Gigabit Ethernet 1
+
+
 Required properties:
 - compatible : shall be one of the following:
 	"marvell,dove-gating-clock" - for Dove SoC clock gating
 	"marvell,kirkwood-gating-clock" - for Kirkwood SoC clock gating
+	"marvell,prestera-kw-gating-clock" - for Preseta SoC clock gating
 - reg : shall be the register address of the Clock Gating Control register
 - #clock-cells : from common clock binding; shall be set to 1
 
diff --git a/drivers/clk/mvebu/clk-gating-ctrl.c b/drivers/clk/mvebu/clk-gating-ctrl.c
index ebf141d..ba37802 100644
--- a/drivers/clk/mvebu/clk-gating-ctrl.c
+++ b/drivers/clk/mvebu/clk-gating-ctrl.c
@@ -203,6 +203,21 @@ static const struct mvebu_soc_descr __initconst kirkwood_gating_descr[] = {
 	{ "tdm", NULL, 20 },
 	{ }
 };
+
+static const struct mvebu_soc_descr __initconst prestera_kw_gating_descr[] = {
+	{ "ge0", NULL, 0 },
+	{ "pex0", NULL, 2 },
+	{ "usb0", NULL, 3 },
+	{ "sdio", NULL, 4 },
+	{ "tsu", NULL, 5 },
+	{ "runit", NULL, 7 },
+	{ "xor0", NULL, 8 },
+	{ "powersave", "cpuclk", 11 },
+	{ "xor1", NULL, 16 },
+	{ "crypto", NULL, 17 },
+	{ "ge1", NULL, 19 },
+	{ }
+};
 #endif
 
 static const __initdata struct of_device_id clk_gating_match[] = {
@@ -232,6 +247,10 @@ static const __initdata struct of_device_id clk_gating_match[] = {
 		.compatible = "marvell,kirkwood-gating-clock",
 		.data = kirkwood_gating_descr,
 	},
+	{
+		.compatible = "marvell,prestera-kw-gating-clock",
+		.data = prestera_kw_gating_descr,
+	},
 #endif
 
 	{ }
-- 
1.8.0.1

[PATCH 2/3] ARM: kirkwood: look for alternative gate ctrl of node

[Valentin Longchamp]

The search for the gate ctrl of node must now also look for the
introduced compatible node.

Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
---
 arch/arm/mach-kirkwood/board-dt.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/mach-kirkwood/board-dt.c b/arch/arm/mach-kirkwood/board-dt.c
index 7904758..3e607c9 100644
--- a/arch/arm/mach-kirkwood/board-dt.c
+++ b/arch/arm/mach-kirkwood/board-dt.c
@@ -44,6 +44,10 @@ static void __init kirkwood_legacy_clk_init(void)
 	struct of_phandle_args clkspec;
 	struct clk *clk;
 
+	if (np == NULL)
+		np = of_find_compatible_node(NULL, NULL,
+			"marvell,prestera-kw-gating-clock");
+
 	clkspec.np = np;
 	clkspec.args_count = 1;
 
-- 
1.8.0.1

[PATCH 3/3] ARM: kirkwood: remove clock gating disabling for km_kirkwood

[Valentin Longchamp]

A new clock gating controller is available for the prestera-kw kirkwood
variant. This controller does not enable the unavailable clk gates.

This patch removes the fixes from the board-km_kirkwood file and enables
the correct clk gating controller for kirkwood-98dx4122.dtsi.

Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
---
 arch/arm/boot/dts/kirkwood-98dx4122.dtsi   |  7 +++++++
 arch/arm/mach-kirkwood/board-km_kirkwood.c | 15 ---------------
 2 files changed, 7 insertions(+), 15 deletions(-)

diff --git a/arch/arm/boot/dts/kirkwood-98dx4122.dtsi b/arch/arm/boot/dts/kirkwood-98dx4122.dtsi
index 3271e4c..8c73673 100644
--- a/arch/arm/boot/dts/kirkwood-98dx4122.dtsi
+++ b/arch/arm/boot/dts/kirkwood-98dx4122.dtsi
@@ -27,5 +27,12 @@
 				marvell,function = "uart1";
 			};
 		};
+
+		gate_clk: clock-gating-control at 2011c {
+			compatible = "marvell,prestera-kw-gating-clock";
+			reg = <0x2011c 0x4>;
+			clocks = <&core_clk 0>;
+			#clock-cells = <1>;
+		};
 	};
 };
diff --git a/arch/arm/mach-kirkwood/board-km_kirkwood.c b/arch/arm/mach-kirkwood/board-km_kirkwood.c
index 44e4605..f1a6ab7 100644
--- a/arch/arm/mach-kirkwood/board-km_kirkwood.c
+++ b/arch/arm/mach-kirkwood/board-km_kirkwood.c
@@ -25,20 +25,5 @@ static struct mv643xx_eth_platform_data km_kirkwood_ge00_data = {
 
 void __init km_kirkwood_init(void)
 {
-	struct clk *sata_clk;
-	/*
-	 * Our variant of kirkwood (integrated in the Bobcat) hangs on accessing
-	 * SATA bits (14-15) of the Clock Gating Control Register. Since these
-	 * devices are also not present in this variant, their clocks get
-	 * disabled because unused when clk_disable_unused() gets called.
-	 * That's why we change the flags to these clocks to CLK_IGNORE_UNUSED
-	 */
-	sata_clk = clk_get_sys("sata_mv.0", "0");
-	if (!IS_ERR(sata_clk))
-		sata_clk->flags |= CLK_IGNORE_UNUSED;
-	sata_clk = clk_get_sys("sata_mv.0", "1");
-	if (!IS_ERR(sata_clk))
-		sata_clk->flags |= CLK_IGNORE_UNUSED;
-
 	kirkwood_ge00_init(&km_kirkwood_ge00_data);
 }
-- 
1.8.0.1

[PATCH 3/3] ARM: kirkwood: remove clock gating disabling for km_kirkwood

[Jason Cooper]

Valentin,

Nice series!  I thought once the mv643xx_eth DT bindings take hold that
this was going to be one of the holdovers with a custom board init file.
Looks like that won't be the case ;-)

On Tue, May 07, 2013 at 05:52:21PM +0200, Valentin Longchamp wrote:
> A new clock gating controller is available for the prestera-kw kirkwood
> variant. This controller does not enable the unavailable clk gates.
> 
> This patch removes the fixes from the board-km_kirkwood file and enables
> the correct clk gating controller for kirkwood-98dx4122.dtsi.
> 
> Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
> ---
>  arch/arm/boot/dts/kirkwood-98dx4122.dtsi   |  7 +++++++
>  arch/arm/mach-kirkwood/board-km_kirkwood.c | 15 ---------------
>  2 files changed, 7 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/kirkwood-98dx4122.dtsi b/arch/arm/boot/dts/kirkwood-98dx4122.dtsi
> index 3271e4c..8c73673 100644
> --- a/arch/arm/boot/dts/kirkwood-98dx4122.dtsi
> +++ b/arch/arm/boot/dts/kirkwood-98dx4122.dtsi
> @@ -27,5 +27,12 @@
>  				marvell,function = "uart1";
>  			};
>  		};
> +
> +		gate_clk: clock-gating-control at 2011c {
> +			compatible = "marvell,prestera-kw-gating-clock";
> +			reg = <0x2011c 0x4>;
> +			clocks = <&core_clk 0>;
> +			#clock-cells = <1>;
> +		};
>  	};
>  };

--->8----

Please split this into two patches, one for the dtsi, and one for code
removal.  It'll prevent merge conflicts and branch dependencies for us.

thx,

Jason.

> diff --git a/arch/arm/mach-kirkwood/board-km_kirkwood.c b/arch/arm/mach-kirkwood/board-km_kirkwood.c
> index 44e4605..f1a6ab7 100644
> --- a/arch/arm/mach-kirkwood/board-km_kirkwood.c
> +++ b/arch/arm/mach-kirkwood/board-km_kirkwood.c
> @@ -25,20 +25,5 @@ static struct mv643xx_eth_platform_data km_kirkwood_ge00_data = {
>  
>  void __init km_kirkwood_init(void)
>  {
> -	struct clk *sata_clk;
> -	/*
> -	 * Our variant of kirkwood (integrated in the Bobcat) hangs on accessing
> -	 * SATA bits (14-15) of the Clock Gating Control Register. Since these
> -	 * devices are also not present in this variant, their clocks get
> -	 * disabled because unused when clk_disable_unused() gets called.
> -	 * That's why we change the flags to these clocks to CLK_IGNORE_UNUSED
> -	 */
> -	sata_clk = clk_get_sys("sata_mv.0", "0");
> -	if (!IS_ERR(sata_clk))
> -		sata_clk->flags |= CLK_IGNORE_UNUSED;
> -	sata_clk = clk_get_sys("sata_mv.0", "1");
> -	if (!IS_ERR(sata_clk))
> -		sata_clk->flags |= CLK_IGNORE_UNUSED;
> -
>  	kirkwood_ge00_init(&km_kirkwood_ge00_data);
>  }
> -- 
> 1.8.0.1
> 

[PATCH 1/3] clk: mvebu: add gate ctrl for Prestera kirkwood variants

[Gregory CLEMENT]

On 05/07/2013 05:52 PM, Valentin Longchamp wrote:
> The kirkwood device found in the Prestera SoCs does not have all the
> peripherals of its the usual kirkwood SoCs. There are hence missing
> clocks in the SoCs.
> 
> This patch registers another gate controller for the kirkwood that
> registers only the available clocks of this kirkwood variant.

Hi Valentin,

Overall the patch set looks OK, however I don't understand why you need
to declare a new gate controller. The list you delcared seemed to be
just a subset of the Kirkwood one, why can't you use this one?

Note that I am not an expert for the kirkwood hardware, so maybe I
missed something.

Regards,

> 
> Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
> ---
>  .../devicetree/bindings/clock/mvebu-gated-clock.txt   | 17 +++++++++++++++++
>  drivers/clk/mvebu/clk-gating-ctrl.c                   | 19 +++++++++++++++++++
>  2 files changed, 36 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/clock/mvebu-gated-clock.txt b/Documentation/devicetree/bindings/clock/mvebu-gated-clock.txt
> index cffc93d..7f494e90 100644
> --- a/Documentation/devicetree/bindings/clock/mvebu-gated-clock.txt
> +++ b/Documentation/devicetree/bindings/clock/mvebu-gated-clock.txt
> @@ -92,10 +92,27 @@ ID	Clock	Peripheral
>  19	ge1	Gigabit Ethernet 1
>  20	tdm	Time Division Mplx
>  
> +The following is a list of provided IDs for Kirkwood Prestera variant:
> +ID	Clock	Peripheral
> +-----------------------------------
> +0	ge0	Gigabit Ethernet 0
> +2	pex0	PCIe Cntrl 0
> +3	usb0	USB Host 0
> +4	sdio	SDIO Cntrl
> +5	tsu	Transp. Stream Unit
> +6	dunit	SDRAM Cntrl
> +7	runit	Runit
> +8	xor0	XOR DMA 0
> +16	xor1	XOR DMA 1
> +17	crypto	CESA engine
> +19	ge1	Gigabit Ethernet 1
> +
> +
>  Required properties:
>  - compatible : shall be one of the following:
>  	"marvell,dove-gating-clock" - for Dove SoC clock gating
>  	"marvell,kirkwood-gating-clock" - for Kirkwood SoC clock gating
> +	"marvell,prestera-kw-gating-clock" - for Preseta SoC clock gating
>  - reg : shall be the register address of the Clock Gating Control register
>  - #clock-cells : from common clock binding; shall be set to 1
>  
> diff --git a/drivers/clk/mvebu/clk-gating-ctrl.c b/drivers/clk/mvebu/clk-gating-ctrl.c
> index ebf141d..ba37802 100644
> --- a/drivers/clk/mvebu/clk-gating-ctrl.c
> +++ b/drivers/clk/mvebu/clk-gating-ctrl.c
> @@ -203,6 +203,21 @@ static const struct mvebu_soc_descr __initconst kirkwood_gating_descr[] = {
>  	{ "tdm", NULL, 20 },
>  	{ }
>  };
> +
> +static const struct mvebu_soc_descr __initconst prestera_kw_gating_descr[] = {
> +	{ "ge0", NULL, 0 },
> +	{ "pex0", NULL, 2 },
> +	{ "usb0", NULL, 3 },
> +	{ "sdio", NULL, 4 },
> +	{ "tsu", NULL, 5 },
> +	{ "runit", NULL, 7 },
> +	{ "xor0", NULL, 8 },
> +	{ "powersave", "cpuclk", 11 },
> +	{ "xor1", NULL, 16 },
> +	{ "crypto", NULL, 17 },
> +	{ "ge1", NULL, 19 },
> +	{ }
> +};
>  #endif
>  
>  static const __initdata struct of_device_id clk_gating_match[] = {
> @@ -232,6 +247,10 @@ static const __initdata struct of_device_id clk_gating_match[] = {
>  		.compatible = "marvell,kirkwood-gating-clock",
>  		.data = kirkwood_gating_descr,
>  	},
> +	{
> +		.compatible = "marvell,prestera-kw-gating-clock",
> +		.data = prestera_kw_gating_descr,
> +	},
>  #endif
>  
>  	{ }
> 


-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

[PATCH 1/3] clk: mvebu: add gate ctrl for Prestera kirkwood variants

[Andrew Lunn]

On Tue, May 07, 2013 at 06:11:44PM +0200, Gregory CLEMENT wrote:
> On 05/07/2013 05:52 PM, Valentin Longchamp wrote:
> > The kirkwood device found in the Prestera SoCs does not have all the
> > peripherals of its the usual kirkwood SoCs. There are hence missing
> > clocks in the SoCs.
> > 
> > This patch registers another gate controller for the kirkwood that
> > registers only the available clocks of this kirkwood variant.
> 
> Hi Valentin,
> 
> Overall the patch set looks OK, however I don't understand why you need
> to declare a new gate controller. The list you delcared seemed to be
> just a subset of the Kirkwood one, why can't you use this one?

Hi Gregory

Take a look at the code which gets deleted in patch 3/3.

       /*
        * Our variant of kirkwood (integrated in the Bobcat) hangs on accessing
        * SATA bits (14-15) of the Clock Gating Control Register. Since these
        * devices are also not present in this variant, their clocks get
        * disabled because unused when clk_disable_unused() gets called.
        * That's why we change the flags to these clocks to CLK_IGNORE_UNUSED
        */

By not defining these clocks in the first place, they never get turned
off...

	Andrew

[PATCH 1/3] clk: mvebu: add gate ctrl for Prestera kirkwood variants

[Sebastian Hesselbarth]

On 05/07/2013 06:11 PM, Gregory CLEMENT wrote:
> On 05/07/2013 05:52 PM, Valentin Longchamp wrote:
>> The kirkwood device found in the Prestera SoCs does not have all the
>> peripherals of its the usual kirkwood SoCs. There are hence missing
>> clocks in the SoCs.
>>
>> This patch registers another gate controller for the kirkwood that
>> registers only the available clocks of this kirkwood variant.
>
> Hi Valentin,
>
> Overall the patch set looks OK, however I don't understand why you need
> to declare a new gate controller. The list you delcared seemed to be
> just a subset of the Kirkwood one, why can't you use this one?
>
> Note that I am not an expert for the kirkwood hardware, so maybe I
> missed something.

I just checked my mails from late 2012 and there Valentin and I agreed,
that not the missing bits in clock gating control registers was the root
cause of km_kirkwood to hang. It was rather the phy gates (that do not/
not yet exist on DT) that caused it to hang, i.e. when accessing SATA
PHY registers.

Valentin, I am not against an extra clock-gating-ctrl for Prestera but
maybe having an kirkwood.dtsi fork without SATA and other peripherals
will also help?

And: Does DT-enabled km_kirkwood ever hang without the hack in it's
board setup? There should be no PHY gates on DT boards..

Sebastian

[PATCH 1/3] clk: mvebu: add gate ctrl for Prestera kirkwood variants

[Valentin Longchamp]

On 05/07/2013 06:36 PM, Sebastian Hesselbarth wrote:
> On 05/07/2013 06:11 PM, Gregory CLEMENT wrote:
>> On 05/07/2013 05:52 PM, Valentin Longchamp wrote:
>>> The kirkwood device found in the Prestera SoCs does not have all the
>>> peripherals of its the usual kirkwood SoCs. There are hence missing
>>> clocks in the SoCs.
>>>
>>> This patch registers another gate controller for the kirkwood that
>>> registers only the available clocks of this kirkwood variant.
>>
>> Hi Valentin,
>>
>> Overall the patch set looks OK, however I don't understand why you need
>> to declare a new gate controller. The list you delcared seemed to be
>> just a subset of the Kirkwood one, why can't you use this one?
>>
>> Note that I am not an expert for the kirkwood hardware, so maybe I
>> missed something.
> 
> I just checked my mails from late 2012 and there Valentin and I agreed,
> that not the missing bits in clock gating control registers was the root
> cause of km_kirkwood to hang. It was rather the phy gates (that do not/
> not yet exist on DT) that caused it to hang, i.e. when accessing SATA
> PHY registers.

Yeah you are right, I had forgotten about this test. I just had a look at the
board-km_kirkwood.c and I tried to figure out a way to make sure the clock gates
bits never get read/written, so never get initialized. But as you say, that's
not the real cause of the hang but

> 
> Valentin, I am not against an extra clock-gating-ctrl for Prestera but
> maybe having an kirkwood.dtsi fork without SATA and other peripherals
> will also help?

Since it's not the real problem having the extra clock-gating-ctrl would me more
consistent with the real Prestera HW, but maybe it's better to keep only one
that works for both as it's already the case, it's less code to maintain.

A better approach would be to work on the kirkwood.dtsi as you mention it. The
SATA node in kirkwood.dtsi is by default disabled, is this enough or should it
be moved to kirkwood-6281.dtsi for instance ?

> 
> And: Does DT-enabled km_kirkwood ever hang without the hack in it's
> board setup? There should be no PHY gates on DT boards..
> 

I have just tested it and it does not hang, so I will submit and patch that
simply removes this workaround since the PHY gates are not accessed anymore
(thanks to DT clock gates and that km_kirkwood does not enable the sata of node).

Valentin

[PATCH 1/3] clk: mvebu: add gate ctrl for Prestera kirkwood variants

[Sebastian Hesselbarth]

On 05/08/2013 09:04 AM, Valentin Longchamp wrote:
> On 05/07/2013 06:36 PM, Sebastian Hesselbarth wrote:
>> I just checked my mails from late 2012 and there Valentin and I agreed,
>> that not the missing bits in clock gating control registers was the root
>> cause of km_kirkwood to hang. It was rather the phy gates (that do not/
>> not yet exist on DT) that caused it to hang, i.e. when accessing SATA
>> PHY registers.
>
> Yeah you are right, I had forgotten about this test. I just had a look at the
> board-km_kirkwood.c and I tried to figure out a way to make sure the clock gates
> bits never get read/written, so never get initialized. But as you say, that's
> not the real cause of the hang but
>
>> Valentin, I am not against an extra clock-gating-ctrl for Prestera but
>> maybe having an kirkwood.dtsi fork without SATA and other peripherals
>> will also help?
>
> Since it's not the real problem having the extra clock-gating-ctrl would me more
> consistent with the real Prestera HW, but maybe it's better to keep only one
> that works for both as it's already the case, it's less code to maintain.
>
> A better approach would be to work on the kirkwood.dtsi as you mention it. The
> SATA node in kirkwood.dtsi is by default disabled, is this enough or should it
> be moved to kirkwood-6281.dtsi for instance ?

Valentin,

I guess for the long run, we will re-introduce phy gates either by
abusing clk gates or some other way. But they will depend on existing
OF nodes.

Considering this, it would be best to fork kirkwood.dtsi for Prestera
and leave out all OF nodes that are not implemented there. We could
have

kirkwood.dtsi -+-> kirkwood-kirkwood.dtsi -+-> kirkwood-6281.dtsi
                +-> kirkwood-prestera.dtsi  +-> kirkwood-6282.dtsi

or any other naming scheme. Maybe Andrew or Jason can comment on this.

>> And: Does DT-enabled km_kirkwood ever hang without the hack in it's
>> board setup? There should be no PHY gates on DT boards..
>
> I have just tested it and it does not hang, so I will submit and patch that
> simply removes this workaround since the PHY gates are not accessed anymore
> (thanks to DT clock gates and that km_kirkwood does not enable the sata of node).

Great! I suggest to also submit the dtsi changes above within the same
patch set.

Sebastian

[PATCH 1/3] clk: mvebu: add gate ctrl for Prestera kirkwood variants

[Jason Cooper]

On Wed, May 08, 2013 at 09:21:40AM +0200, Sebastian Hesselbarth wrote:
> On 05/08/2013 09:04 AM, Valentin Longchamp wrote:
> >On 05/07/2013 06:36 PM, Sebastian Hesselbarth wrote:
> >>I just checked my mails from late 2012 and there Valentin and I agreed,
> >>that not the missing bits in clock gating control registers was the root
> >>cause of km_kirkwood to hang. It was rather the phy gates (that do not/
> >>not yet exist on DT) that caused it to hang, i.e. when accessing SATA
> >>PHY registers.
> >
> >Yeah you are right, I had forgotten about this test. I just had a look at the
> >board-km_kirkwood.c and I tried to figure out a way to make sure the clock gates
> >bits never get read/written, so never get initialized. But as you say, that's
> >not the real cause of the hang but
> >
> >>Valentin, I am not against an extra clock-gating-ctrl for Prestera but
> >>maybe having an kirkwood.dtsi fork without SATA and other peripherals
> >>will also help?
> >
> >Since it's not the real problem having the extra clock-gating-ctrl would me more
> >consistent with the real Prestera HW, but maybe it's better to keep only one
> >that works for both as it's already the case, it's less code to maintain.
> >
> >A better approach would be to work on the kirkwood.dtsi as you mention it. The
> >SATA node in kirkwood.dtsi is by default disabled, is this enough or should it
> >be moved to kirkwood-6281.dtsi for instance ?
> 
> Valentin,
> 
> I guess for the long run, we will re-introduce phy gates either by
> abusing clk gates or some other way. But they will depend on existing
> OF nodes.
> 
> Considering this, it would be best to fork kirkwood.dtsi for Prestera
> and leave out all OF nodes that are not implemented there. We could
> have
> 
> kirkwood.dtsi -+-> kirkwood-kirkwood.dtsi -+-> kirkwood-6281.dtsi
>                +-> kirkwood-prestera.dtsi  +-> kirkwood-6282.dtsi

or,

kirkwood.dtsi
prestera.dtsi

-pinctrl-
kirkwood-98dx4122.dtsi (should rename to prestera-, but seems churn-ish)
kirkwood-6281.dtsi
kirkwood-6282.dtsi

-dts-
kirkwood-km_kirkwood.dts (rename/churn prestera-?)
  |-prestera.dtsi
  \-kirkwood-98dx4122.dtsi

or, honestly, how many boards are going to be based on prestera?  If
it's just the one, why not combine all the nodes into
kirkwood-km_kirkwood.dts?


thx,

Jason.