[v2] arm64: dts: ti: k3-am642-sr-som: mux ethernet phy reset signals input

[PATCH v2] arm64: dts: ti: k3-am642-sr-som: mux ethernet phy reset signals input

Posted by Josua Mayer 1 year, 3 months ago

Specifically on AM64 SoM design, the DP83869 phys have a chance to lock
up if reset gpio changes state. Update the pinmux to input-only,
strongly enforcing that these signals are left floating at all times.

This avoids sporadic phy initialisation errors mostly encountered during
power-on and reset. In this state the phys respond to all mdio messages
with a constant response, recovering only after power-cycle.

Signed-off-by: Josua Mayer <josua@solid-run.com>
---
Changes in v2:
- update commit message with additional details
- rebased on v6.11-rc1
- Link to v1: https://lore.kernel.org/r/20240704-am64-phy-lockup-v1-1-4a38ded44f9d@solid-run.com
---
 arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi b/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
index c19d0b8bbf0f..b1f06071df4c 100644
--- a/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
@@ -320,7 +320,7 @@ AM64X_IOPAD(0x0278, PIN_INPUT, 7) /* EXTINTn.GPIO1_70 */
 	ethernet_phy0_default_pins: ethernet-phy0-default-pins {
 		pinctrl-single,pins = <
 			/* reset */
-			AM64X_IOPAD(0x0154, PIN_OUTPUT, 7) /* PRG1_PRU1_GPO19.GPIO0_84 */
+			AM64X_IOPAD(0x0154, PIN_INPUT, 7) /* PRG1_PRU1_GPO19.GPIO0_84 */
 			/* reference clock */
 			AM64X_IOPAD(0x0274, PIN_OUTPUT, 5) /* EXT_REFCLK1.CLKOUT0 */
 		>;
@@ -329,7 +329,7 @@ AM64X_IOPAD(0x0274, PIN_OUTPUT, 5) /* EXT_REFCLK1.CLKOUT0 */
 	ethernet_phy1_default_pins: ethernet-phy1-default-pins {
 		pinctrl-single,pins = <
 			/* reset */
-			AM64X_IOPAD(0x0150, PIN_OUTPUT, 7) /* PRG1_PRU1_GPO18.GPIO0_20 */
+			AM64X_IOPAD(0x0150, PIN_INPUT, 7) /* PRG1_PRU1_GPO18.GPIO0_20 */
 			/* led0, external pull-down on SoM */
 			AM64X_IOPAD(0x0128, PIN_INPUT, 7) /* PRG1_PRU1_GPO8.GPIO0_73 */
 			/* led1/rxer */
@@ -340,7 +340,7 @@ AM64X_IOPAD(0x011c, PIN_INPUT, 7) /* PRG1_PRU1_GPO5.GPIO0_70 */
 	ethernet_phy2_default_pins: ethernet-phy2-default-pins {
 		pinctrl-single,pins = <
 			/* reset */
-			AM64X_IOPAD(0x00d4, PIN_OUTPUT, 7) /* PRG1_PRU0_GPO7.GPIO0_52 */
+			AM64X_IOPAD(0x00d4, PIN_INPUT, 7) /* PRG1_PRU0_GPO7.GPIO0_52 */
 			/* led0, external pull-down on SoM */
 			AM64X_IOPAD(0x00d8, PIN_INPUT, 7) /* PRG1_PRU0_GPO8.GPIO0_53 */
 			/* led1/rxer */

---
base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b
change-id: 20240704-am64-phy-lockup-107ea5ffa228

Best regards,
-- 
Josua Mayer <josua@solid-run.com>

Re: [PATCH v2] arm64: dts: ti: k3-am642-sr-som: mux ethernet phy reset signals input

Posted by Nishanth Menon 1 year, 3 months ago

On 11:52-20240903, Josua Mayer wrote:
> Specifically on AM64 SoM design, the DP83869 phys have a chance to lock
> up if reset gpio changes state. Update the pinmux to input-only,
> strongly enforcing that these signals are left floating at all times.
> 
> This avoids sporadic phy initialisation errors mostly encountered during
> power-on and reset. In this state the phys respond to all mdio messages
> with a constant response, recovering only after power-cycle.
> 
> Signed-off-by: Josua Mayer <josua@solid-run.com>
> ---
> Changes in v2:
> - update commit message with additional details
> - rebased on v6.11-rc1
> - Link to v1: https://lore.kernel.org/r/20240704-am64-phy-lockup-v1-1-4a38ded44f9d@solid-run.com
> ---
>  arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi b/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
> index c19d0b8bbf0f..b1f06071df4c 100644
> --- a/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
> @@ -320,7 +320,7 @@ AM64X_IOPAD(0x0278, PIN_INPUT, 7) /* EXTINTn.GPIO1_70 */
>  	ethernet_phy0_default_pins: ethernet-phy0-default-pins {
>  		pinctrl-single,pins = <
>  			/* reset */
> -			AM64X_IOPAD(0x0154, PIN_OUTPUT, 7) /* PRG1_PRU1_GPO19.GPIO0_84 */
> +			AM64X_IOPAD(0x0154, PIN_INPUT, 7) /* PRG1_PRU1_GPO19.GPIO0_84 */
>  			/* reference clock */
>  			AM64X_IOPAD(0x0274, PIN_OUTPUT, 5) /* EXT_REFCLK1.CLKOUT0 */
>  		>;
> @@ -329,7 +329,7 @@ AM64X_IOPAD(0x0274, PIN_OUTPUT, 5) /* EXT_REFCLK1.CLKOUT0 */
>  	ethernet_phy1_default_pins: ethernet-phy1-default-pins {
>  		pinctrl-single,pins = <
>  			/* reset */
> -			AM64X_IOPAD(0x0150, PIN_OUTPUT, 7) /* PRG1_PRU1_GPO18.GPIO0_20 */
> +			AM64X_IOPAD(0x0150, PIN_INPUT, 7) /* PRG1_PRU1_GPO18.GPIO0_20 */
>  			/* led0, external pull-down on SoM */
>  			AM64X_IOPAD(0x0128, PIN_INPUT, 7) /* PRG1_PRU1_GPO8.GPIO0_73 */
>  			/* led1/rxer */
> @@ -340,7 +340,7 @@ AM64X_IOPAD(0x011c, PIN_INPUT, 7) /* PRG1_PRU1_GPO5.GPIO0_70 */
>  	ethernet_phy2_default_pins: ethernet-phy2-default-pins {
>  		pinctrl-single,pins = <
>  			/* reset */
> -			AM64X_IOPAD(0x00d4, PIN_OUTPUT, 7) /* PRG1_PRU0_GPO7.GPIO0_52 */
> +			AM64X_IOPAD(0x00d4, PIN_INPUT, 7) /* PRG1_PRU0_GPO7.GPIO0_52 */

PIN_INPUT is bi-directional despite what the name states. Either way, it
is a bit late for me to pick things up.

>  			/* led0, external pull-down on SoM */
>  			AM64X_IOPAD(0x00d8, PIN_INPUT, 7) /* PRG1_PRU0_GPO8.GPIO0_53 */
>  			/* led1/rxer */
> 
> ---
> base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b
> change-id: 20240704-am64-phy-lockup-107ea5ffa228
> 
> Best regards,
> -- 
> Josua Mayer <josua@solid-run.com>
> 

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D

Re: [PATCH v2] arm64: dts: ti: k3-am642-sr-som: mux ethernet phy reset signals input

Posted by Josua Mayer 1 year, 3 months ago

Am 03.09.24 um 14:42 schrieb Nishanth Menon:
> On 11:52-20240903, Josua Mayer wrote:
>> Specifically on AM64 SoM design, the DP83869 phys have a chance to lock
>> up if reset gpio changes state. Update the pinmux to input-only,
>> strongly enforcing that these signals are left floating at all times.
>>
>> This avoids sporadic phy initialisation errors mostly encountered during
>> power-on and reset. In this state the phys respond to all mdio messages
>> with a constant response, recovering only after power-cycle.
>>
>> Signed-off-by: Josua Mayer <josua@solid-run.com>
>> ---
>> Changes in v2:
>> - update commit message with additional details
>> - rebased on v6.11-rc1
>> - Link to v1: https://lore.kernel.org/r/20240704-am64-phy-lockup-v1-1-4a38ded44f9d@solid-run.com
>> ---
>>  arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi | 6 +++---
>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi b/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
>> index c19d0b8bbf0f..b1f06071df4c 100644
>> --- a/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
>> +++ b/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
>> @@ -320,7 +320,7 @@ AM64X_IOPAD(0x0278, PIN_INPUT, 7) /* EXTINTn.GPIO1_70 */
>>  	ethernet_phy0_default_pins: ethernet-phy0-default-pins {
>>  		pinctrl-single,pins = <
>>  			/* reset */
>> -			AM64X_IOPAD(0x0154, PIN_OUTPUT, 7) /* PRG1_PRU1_GPO19.GPIO0_84 */
>> +			AM64X_IOPAD(0x0154, PIN_INPUT, 7) /* PRG1_PRU1_GPO19.GPIO0_84 */
>>  			/* reference clock */
>>  			AM64X_IOPAD(0x0274, PIN_OUTPUT, 5) /* EXT_REFCLK1.CLKOUT0 */
>>  		>;
>> @@ -329,7 +329,7 @@ AM64X_IOPAD(0x0274, PIN_OUTPUT, 5) /* EXT_REFCLK1.CLKOUT0 */
>>  	ethernet_phy1_default_pins: ethernet-phy1-default-pins {
>>  		pinctrl-single,pins = <
>>  			/* reset */
>> -			AM64X_IOPAD(0x0150, PIN_OUTPUT, 7) /* PRG1_PRU1_GPO18.GPIO0_20 */
>> +			AM64X_IOPAD(0x0150, PIN_INPUT, 7) /* PRG1_PRU1_GPO18.GPIO0_20 */
>>  			/* led0, external pull-down on SoM */
>>  			AM64X_IOPAD(0x0128, PIN_INPUT, 7) /* PRG1_PRU1_GPO8.GPIO0_73 */
>>  			/* led1/rxer */
>> @@ -340,7 +340,7 @@ AM64X_IOPAD(0x011c, PIN_INPUT, 7) /* PRG1_PRU1_GPO5.GPIO0_70 */
>>  	ethernet_phy2_default_pins: ethernet-phy2-default-pins {
>>  		pinctrl-single,pins = <
>>  			/* reset */
>> -			AM64X_IOPAD(0x00d4, PIN_OUTPUT, 7) /* PRG1_PRU0_GPO7.GPIO0_52 */
>> +			AM64X_IOPAD(0x00d4, PIN_INPUT, 7) /* PRG1_PRU0_GPO7.GPIO0_52 */
> PIN_INPUT is bi-directional despite what the name states.
Good point, I will try to measure the electrical signal during boot
and better understand what exactly happens.

Guess is there are glitches when either u-boot or linux
are changing the pinmux registers.
Hence whatever glitch-free value we end up picking for u-boot
should be reflected in linux dts also.

> Either way, it
> is a bit late for me to pick things up.
>
>>  			/* led0, external pull-down on SoM */
>>  			AM64X_IOPAD(0x00d8, PIN_INPUT, 7) /* PRG1_PRU0_GPO8.GPIO0_53 */
>>  			/* led1/rxer */
>>
>> ---
>> base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b
>> change-id: 20240704-am64-phy-lockup-107ea5ffa228
>>
>> Best regards,
>> -- 
>> Josua Mayer <josua@solid-run.com>
>>

Re: [PATCH v2] arm64: dts: ti: k3-am642-sr-som: mux ethernet phy reset signals input

Posted by Josua Mayer 1 year, 2 months ago

Hi Nishanth,

Am 14.09.24 um 11:34 schrieb Josua Mayer:
> Am 03.09.24 um 14:42 schrieb Nishanth Menon:
>> On 11:52-20240903, Josua Mayer wrote:
>>> Specifically on AM64 SoM design, the DP83869 phys have a chance to lock
>>> up if reset gpio changes state. Update the pinmux to input-only,
>>> strongly enforcing that these signals are left floating at all times.
>>>
>>> This avoids sporadic phy initialisation errors mostly encountered during
>>> power-on and reset. In this state the phys respond to all mdio messages
>>> with a constant response, recovering only after power-cycle.
>>>
>>> Signed-off-by: Josua Mayer <josua@solid-run.com>
>>> ---
>>> Changes in v2:
>>> - update commit message with additional details
>>> - rebased on v6.11-rc1
>>> - Link to v1: https://lore.kernel.org/r/20240704-am64-phy-lockup-v1-1-4a38ded44f9d@solid-run.com
>>> ---
>>>  arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi | 6 +++---
>>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi b/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
>>> index c19d0b8bbf0f..b1f06071df4c 100644
>>> --- a/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
>>> +++ b/arch/arm64/boot/dts/ti/k3-am642-sr-som.dtsi
>>> @@ -320,7 +320,7 @@ AM64X_IOPAD(0x0278, PIN_INPUT, 7) /* EXTINTn.GPIO1_70 */
>>>  	ethernet_phy0_default_pins: ethernet-phy0-default-pins {
>>>  		pinctrl-single,pins = <
>>>  			/* reset */
>>> -			AM64X_IOPAD(0x0154, PIN_OUTPUT, 7) /* PRG1_PRU1_GPO19.GPIO0_84 */
>>> +			AM64X_IOPAD(0x0154, PIN_INPUT, 7) /* PRG1_PRU1_GPO19.GPIO0_84 */
>>>  			/* reference clock */
>>>  			AM64X_IOPAD(0x0274, PIN_OUTPUT, 5) /* EXT_REFCLK1.CLKOUT0 */
>>>  		>;
>>> @@ -329,7 +329,7 @@ AM64X_IOPAD(0x0274, PIN_OUTPUT, 5) /* EXT_REFCLK1.CLKOUT0 */
>>>  	ethernet_phy1_default_pins: ethernet-phy1-default-pins {
>>>  		pinctrl-single,pins = <
>>>  			/* reset */
>>> -			AM64X_IOPAD(0x0150, PIN_OUTPUT, 7) /* PRG1_PRU1_GPO18.GPIO0_20 */
>>> +			AM64X_IOPAD(0x0150, PIN_INPUT, 7) /* PRG1_PRU1_GPO18.GPIO0_20 */
>>>  			/* led0, external pull-down on SoM */
>>>  			AM64X_IOPAD(0x0128, PIN_INPUT, 7) /* PRG1_PRU1_GPO8.GPIO0_73 */
>>>  			/* led1/rxer */
>>> @@ -340,7 +340,7 @@ AM64X_IOPAD(0x011c, PIN_INPUT, 7) /* PRG1_PRU1_GPO5.GPIO0_70 */
>>>  	ethernet_phy2_default_pins: ethernet-phy2-default-pins {
>>>  		pinctrl-single,pins = <
>>>  			/* reset */
>>> -			AM64X_IOPAD(0x00d4, PIN_OUTPUT, 7) /* PRG1_PRU0_GPO7.GPIO0_52 */
>>> +			AM64X_IOPAD(0x00d4, PIN_INPUT, 7) /* PRG1_PRU0_GPO7.GPIO0_52 */
>> PIN_INPUT is bi-directional despite what the name states.
> Good point, I will try to measure the electrical signal during boot
> and better understand what exactly happens.
>
> Guess is there are glitches when either u-boot or linux
> are changing the pinmux registers.
> Hence whatever glitch-free value we end up picking for u-boot
> should be reflected in linux dts also.

I have measured the reset signals with a scope during power-on and reboot:
You were indeed correct that there are no glitches in the mux.

In early prototypes we had pull-down for each reset,
and it was easy to reproduce the problematic state of phy.

They have long since been removed.

>
>> Either way, it
>> is a bit late for me to pick things up.
For now, please nack, the changes do not in fact accomplish their purpose.
>>
>>>  			/* led0, external pull-down on SoM */
>>>  			AM64X_IOPAD(0x00d8, PIN_INPUT, 7) /* PRG1_PRU0_GPO8.GPIO0_53 */
>>>  			/* led1/rxer */
>>>
>>> ---
>>> base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b
>>> change-id: 20240704-am64-phy-lockup-107ea5ffa228
>>>
>>> Best regards,
>>> -- 
>>> Josua Mayer <josua@solid-run.com>
>>>