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Message-ID: <cf9f8d95-0f52-b37e-bb97-0382fed01b6a@ti.com>
Date:   Wed, 13 Sep 2023 11:35:58 +0530
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Subject: Re: [PATCH 2/3] arm64: dts: ti: am654-base-board: add ICSSG2 Ethernet
 support
Content-Language: en-US
To:     Andrew Davis <afd@ti.com>, Vignesh Raghavendra <vigneshr@ti.com>,
        Nishanth Menon <nm@ti.com>
CC:     Conor Dooley <conor+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Tero Kristo <kristo@kernel.org>,
        <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>, <srk@ti.com>,
        <r-gunasekaran@ti.com>
References: <20230911071245.2173520-1-danishanwar@ti.com>
 <20230911071245.2173520-3-danishanwar@ti.com>
 <1e1577a5-fb01-c84b-ede0-38058387ec23@ti.com>
 <6503ca2b-c55a-ab26-6e0c-121aeb5c1c66@ti.com>
 <6cb40b09-8154-5ef4-cbbc-9dfc5994a031@ti.com>
From:   MD Danish Anwar <danishanwar@ti.com>
In-Reply-To: <6cb40b09-8154-5ef4-cbbc-9dfc5994a031@ti.com>
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On 12/09/23 20:28, Andrew Davis wrote:
> On 9/12/23 3:29 AM, MD Danish Anwar wrote:
>> Hi Andrew,
>>
>> On 11/09/23 18:35, Andrew Davis wrote:
>>> On 9/11/23 2:12 AM, MD Danish Anwar wrote:
>>>> ICSSG2 provides dual Gigabit Ethernet support.
>>>>
>>>> For support SR2.0 ICSSG Ethernet firmware:
>>>> - provide different firmware blobs and use TX_PRU.
>>>> - IEP0 is used as PTP Hardware Clock and can only be used for one port.
>>>> - TX timestamp notification comes via INTC interrupt.
>>>>
>>>> Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
>>>> ---
>>>>    .../arm64/boot/dts/ti/k3-am654-base-board.dts | 123
>>>> ++++++++++++++++++
>>>
>>> Adding this to the base dts? What if I want to use my PRUs for something
>>> else? These "application nodes" define a single usecase out of many
>>> possible, and should IMHO always be in overlays so users can select
>>> which
>>> they want easily.
>>>
>>
>> The base board (AM654x-EVM) has two Ethernet ports dedicated for ICSSG.
>> The expectation is that when a user boots up AM654x-EVM, ICSSG is
>> supported on those two ports by default. If the icssg nodes are not
>> added to base dts then by default the two Ethernet ports will have no
>> functionality.
>>
> 
> This is *your* default use-case for these PRUs, mine might be different.
> I can agree that most might want this use-case too and this is the one
> intended as the demo for these ports on this board. What I am saying is
> that when one wants to use these PRUs for something else, having this
> one application baked into the base DTB makes it very difficult to switch.
> 

This is the intended use case. The base board has two ICSSG Ethernet
ports. My understanding is that device trees describe the hardware.

The base board dts should describe the base board hardware which has the
two ICSSG ports. So the base board dts should contain nodes to enable
those two ports.

Any hardware component that is not present in the base board should be
applied as an overlay.

For example in the AM654x-IDK, we have extra IDK card applied on the
base board. This IDK card contains 4 ICSSG Ethernet ports. The nodes for
these 4 ICSSG port should go in an overlay i.e. k3-am654-idk.dtso which
I am doing as part of the patch 3 of this series.

My understanding is that any hardware component that is part of the base
board should be described in base-board.dts. Any hardware component that
is not part of the base board and is added by extra cards should be
described in overlays.

>> The primary use case is that ICSSG should support on those two ports in
>> AM654x-EVM by default. The user should not need to apply any overlay to
>> get the two ports working. So In order to achieve that I think it is OK
>> to add the ICSSG nodes in the base board dts file.
>>
> 
> A user does not need to apply an overlay to use these, this application
> node overlay can be applied at build time. You can even rename the base
> .dtb to be the one that has this overlay applied by default.
> 
> Take a look at k3-am654-gp-evm.dtb, it is a composite DTB built from
> the "base-board" DTB and the "rocktech-rk101-panel" DTBO applied on top.
> This combination is what we call and sell as the "GP EVM", and you
> can use it by booting the "k3-am654-gp-evm.dtb". Now let's say you
> want to use a different panel, all you need to do is take the base-
> board and apply a different panel overlay. Had we hard-coded the
> "default" panel into the base-board DTS then a user with a different
> panel would have to go and edit the DTS to remove all the rk101-panel
> bits.
> 

This is one way to do it. But I still think the best way to do this is
to have the ICSSG nodes in base board dts as the ICSSG hardware is
present on the base board.

>> If user wants to use PRUs for something else, we can have overlay for
>> those. But we should not need to apply any overlay to achieve the
>> primary functionality i.e. ICSSG working in the two dedicated ICSSG
>> Ethernet ports.
>>
> 
> They could *not* simply add a different overlay for their usecase as
> you have baked your usecase into the base DTB. Their overlay would
> have to have a bunch of /delete-node/ junk to remove your "defaults".
> 

This patch adds one node "icssg2-eth" which uses six PRUs. If user wants
to use PRUs for something else they can add "/delete-node/ &icssg2_eth"
in the overlay.

> As above, if this is the "primary functionality" then have this
> overlay applied by default:
> 
> --- a/arch/arm64/boot/dts/ti/Makefile
> +++ b/arch/arm64/boot/dts/ti/Makefile
> @@ -42,7 +42,7 @@ dtb-$(CONFIG_ARCH_K3) +=
> k3-am642-tqma64xxl-mbax4xxl-sdcard.dtb
>  dtb-$(CONFIG_ARCH_K3) += k3-am642-tqma64xxl-mbax4xxl-wlan.dtb
>  
>  # Boards with AM65x SoC
> -k3-am654-gp-evm-dtbs := k3-am654-base-board.dtb
> k3-am654-base-board-rocktech-rk101-panel.dtbo
> +k3-am654-gp-evm-dtbs := k3-am654-base-board.dtb
> k3-am654-base-board-rocktech-rk101-panel.dtbo
> k3-am654-base-board-prueth.dtbo
>  dtb-$(CONFIG_ARCH_K3) += k3-am6528-iot2050-basic.dtb
>  dtb-$(CONFIG_ARCH_K3) += k3-am6528-iot2050-basic-pg2.dtb
>  dtb-$(CONFIG_ARCH_K3) += k3-am6548-iot2050-advanced.dtb
> 
> Andrew
> 
>>
>>> Andrew
>>>
>>>>    1 file changed, 123 insertions(+)
>>>>
>>>> diff --git a/arch/arm64/boot/dts/ti/k3-am654-base-board.dts
>>>> b/arch/arm64/boot/dts/ti/k3-am654-base-board.dts
>>>> index f5c26e9fba98..5cf9546ff9f7 100644
>>>> --- a/arch/arm64/boot/dts/ti/k3-am654-base-board.dts
>>>> +++ b/arch/arm64/boot/dts/ti/k3-am654-base-board.dts
>>>> @@ -25,6 +25,8 @@ aliases {
>>>>            ethernet0 = &cpsw_port1;
>>>>            mmc0 = &sdhci0;
>>>>            mmc1 = &sdhci1;
>>>> +        ethernet1 = &icssg2_emac0;
>>>> +        ethernet2 = &icssg2_emac1;
>>>>        };
>>>>          chosen {
>>>> @@ -144,6 +146,72 @@ vtt_supply: regulator-3 {
>>>>            vin-supply = <&vcc3v3_io>;
>>>>            gpio = <&wkup_gpio0 28 GPIO_ACTIVE_HIGH>;
>>>>        };
>>>> +
>>>> +    /* Dual Ethernet application node on PRU-ICSSG2 */
>>>> +    icssg2_eth: icssg2-eth {
>>>> +        compatible = "ti,am654-icssg-prueth";
>>>> +        pinctrl-names = "default";
>>>> +        pinctrl-0 = <&icssg2_rgmii_pins_default>;
>>>> +        sram = <&msmc_ram>;
>>>> +        ti,prus = <&pru2_0>, <&rtu2_0>, <&tx_pru2_0>,
>>>> +            <&pru2_1>, <&rtu2_1>, <&tx_pru2_1>;
>>>> +        firmware-name = "ti-pruss/am65x-sr2-pru0-prueth-fw.elf",
>>>> +                "ti-pruss/am65x-sr2-rtu0-prueth-fw.elf",
>>>> +                "ti-pruss/am65x-sr2-txpru0-prueth-fw.elf",
>>>> +                "ti-pruss/am65x-sr2-pru1-prueth-fw.elf",
>>>> +                "ti-pruss/am65x-sr2-rtu1-prueth-fw.elf",
>>>> +                "ti-pruss/am65x-sr2-txpru1-prueth-fw.elf";
>>>> +
>>>> +        ti,pruss-gp-mux-sel = <2>,      /* MII mode */
>>>> +                      <2>,
>>>> +                      <2>,
>>>> +                      <2>,    /* MII mode */
>>>> +                      <2>,
>>>> +                      <2>;
>>>> +
>>>> +        ti,mii-g-rt = <&icssg2_mii_g_rt>;
>>>> +        ti,mii-rt = <&icssg2_mii_rt>;
>>>> +        ti,iep = <&icssg2_iep0>, <&icssg2_iep1>;
>>>> +
>>>> +        interrupt-parent = <&icssg2_intc>;
>>>> +        interrupts = <24 0 2>, <25 1 3>;
>>>> +        interrupt-names = "tx_ts0", "tx_ts1";
>>>> +
>>>> +        dmas = <&main_udmap 0xc300>, /* egress slice 0 */
>>>> +               <&main_udmap 0xc301>, /* egress slice 0 */
>>>> +               <&main_udmap 0xc302>, /* egress slice 0 */
>>>> +               <&main_udmap 0xc303>, /* egress slice 0 */
>>>> +               <&main_udmap 0xc304>, /* egress slice 1 */
>>>> +               <&main_udmap 0xc305>, /* egress slice 1 */
>>>> +               <&main_udmap 0xc306>, /* egress slice 1 */
>>>> +               <&main_udmap 0xc307>, /* egress slice 1 */
>>>> +               <&main_udmap 0x4300>, /* ingress slice 0 */
>>>> +               <&main_udmap 0x4301>; /* ingress slice 1 */
>>>> +
>>>> +        dma-names = "tx0-0", "tx0-1", "tx0-2", "tx0-3",
>>>> +                "tx1-0", "tx1-1", "tx1-2", "tx1-3",
>>>> +                "rx0", "rx1";
>>>> +        ethernet-ports {
>>>> +            #address-cells = <1>;
>>>> +            #size-cells = <0>;
>>>> +            icssg2_emac0: port@0 {
>>>> +                reg = <0>;
>>>> +                phy-handle = <&icssg2_phy0>;
>>>> +                phy-mode = "rgmii-id";
>>>> +                ti,syscon-rgmii-delay = <&scm_conf 0x4120>;
>>>> +                /* Filled in by bootloader */
>>>> +                local-mac-address = [00 00 00 00 00 00];
>>>> +            };
>>>> +            icssg2_emac1: port@1 {
>>>> +                reg = <1>;
>>>> +                phy-handle = <&icssg2_phy1>;
>>>> +                phy-mode = "rgmii-id";
>>>> +                ti,syscon-rgmii-delay = <&scm_conf 0x4124>;
>>>> +                /* Filled in by bootloader */
>>>> +                local-mac-address = [00 00 00 00 00 00];
>>>> +            };
>>>> +        };
>>>> +    };
>>>>    };
>>>>      &wkup_pmx0 {
>>>> @@ -300,6 +368,43 @@ usb1_pins_default: usb1-default-pins {
>>>>                AM65X_IOPAD(0x02c0, PIN_OUTPUT, 0) /* (AC8)
>>>> USB1_DRVVBUS */
>>>>            >;
>>>>        };
>>>> +
>>>> +    icssg2_mdio_pins_default: icssg2-mdio-default-pins {
>>>> +        pinctrl-single,pins = <
>>>> +            AM65X_IOPAD(0x0094, PIN_INPUT, 2) /* (AC19)
>>>> PRG2_PRU0_GPO7.PRG2_MDIO0_MDIO */
>>>> +            AM65X_IOPAD(0x00c8, PIN_OUTPUT, 2) /* (AE15)
>>>> PRG2_PRU1_GPO7.PRG2_MDIO0_MDC */
>>>> +        >;
>>>> +    };
>>>> +
>>>> +    icssg2_rgmii_pins_default: icssg2-rgmii-default-pins {
>>>> +        pinctrl-single,pins = <
>>>> +            AM65X_IOPAD(0x00ac, PIN_INPUT, 2) /* (AH15)
>>>> PRG2_PRU1_GPO0.PRG2_RGMII2_RD0 */
>>>> +            AM65X_IOPAD(0x00b0, PIN_INPUT, 2) /* (AC16)
>>>> PRG2_PRU1_GPO1.PRG2_RGMII2_RD1 */
>>>> +            AM65X_IOPAD(0x00b4, PIN_INPUT, 2) /* (AD17)
>>>> PRG2_PRU1_GPO2.PRG2_RGMII2_RD2 */
>>>> +            AM65X_IOPAD(0x00b8, PIN_INPUT, 2) /* (AH14)
>>>> PRG2_PRU1_GPO3.PRG2_RGMII2_RD3 */
>>>> +            AM65X_IOPAD(0x00cc, PIN_OUTPUT, 2) /* (AD15)
>>>> PRG2_PRU1_GPO8.PRG2_RGMII2_TD0 */
>>>> +            AM65X_IOPAD(0x00d0, PIN_OUTPUT, 2) /* (AF14)
>>>> PRG2_PRU1_GPO9.PRG2_RGMII2_TD1 */
>>>> +            AM65X_IOPAD(0x00d4, PIN_OUTPUT, 2) /* (AC15)
>>>> PRG2_PRU1_GPO10.PRG2_RGMII2_TD2 */
>>>> +            AM65X_IOPAD(0x00d8, PIN_OUTPUT, 2) /* (AD14)
>>>> PRG2_PRU1_GPO11.PRG2_RGMII2_TD3 */
>>>> +            AM65X_IOPAD(0x00dc, PIN_INPUT, 2) /* (AE14)
>>>> PRG2_PRU1_GPO16.PRG2_RGMII2_TXC */
>>>> +            AM65X_IOPAD(0x00c4, PIN_OUTPUT, 2) /* (AC17)
>>>> PRG2_PRU1_GPO6.PRG2_RGMII2_TX_CTL */
>>>> +            AM65X_IOPAD(0x00c0, PIN_INPUT, 2) /* (AG15)
>>>> PRG2_PRU1_GPO5.PRG2_RGMII2_RXC */
>>>> +            AM65X_IOPAD(0x00bc, PIN_INPUT, 2) /* (AG14)
>>>> PRG2_PRU1_GPO4.PRG2_RGMII2_RX_CTL */
>>>> +
>>>> +            AM65X_IOPAD(0x0078, PIN_INPUT, 2) /* (AF18)
>>>> PRG2_PRU0_GPO0.PRG2_RGMII1_RD0 */
>>>> +            AM65X_IOPAD(0x007c, PIN_INPUT, 2) /* (AE18)
>>>> PRG2_PRU0_GPO1.PRG2_RGMII1_RD1 */
>>>> +            AM65X_IOPAD(0x0080, PIN_INPUT, 2) /* (AH17)
>>>> PRG2_PRU0_GPO2.PRG2_RGMII1_RD2 */
>>>> +            AM65X_IOPAD(0x0084, PIN_INPUT, 2) /* (AG18)
>>>> PRG2_PRU0_GPO3.PRG2_RGMII1_RD3 */
>>>> +            AM65X_IOPAD(0x0098, PIN_OUTPUT, 2) /* (AH16)
>>>> PRG2_PRU0_GPO8.PRG2_RGMII1_TD0 */
>>>> +            AM65X_IOPAD(0x009c, PIN_OUTPUT, 2) /* (AG16)
>>>> PRG2_PRU0_GPO9.PRG2_RGMII1_TD1 */
>>>> +            AM65X_IOPAD(0x00a0, PIN_OUTPUT, 2) /* (AF16)
>>>> PRG2_PRU0_GPO10.PRG2_RGMII1_TD2 */
>>>> +            AM65X_IOPAD(0x00a4, PIN_OUTPUT, 2) /* (AE16)
>>>> PRG2_PRU0_GPO11.PRG2_RGMII1_TD3 */
>>>> +            AM65X_IOPAD(0x00a8, PIN_INPUT, 2) /* (AD16)
>>>> PRG2_PRU0_GPO16.PRG2_RGMII1_TXC */
>>>> +            AM65X_IOPAD(0x0090, PIN_OUTPUT, 2) /* (AE17)
>>>> PRG2_PRU0_GPO6.PRG2_RGMII1_TX_CTL */
>>>> +            AM65X_IOPAD(0x008c, PIN_INPUT, 2) /* (AF17)
>>>> PRG2_PRU0_GPO5.PRG2_RGMII1_RXC */
>>>> +            AM65X_IOPAD(0x0088, PIN_INPUT, 2) /* (AG17)
>>>> PRG2_PRU0_GPO4.PRG2_RGMII1_RX_CTL */
>>>> +        >;
>>>> +    };
>>>>    };
>>>>      &main_pmx1 {
>>>> @@ -621,3 +726,21 @@ &cpsw_port1 {
>>>>    &dss {
>>>>        status = "disabled";
>>>>    };
>>>> +
>>>> +&icssg2_mdio {
>>>> +    status = "okay";
>>>> +    pinctrl-names = "default";
>>>> +    pinctrl-0 = <&icssg2_mdio_pins_default>;
>>>> +
>>>> +    icssg2_phy0: ethernet-phy@0 {
>>>> +        reg = <0>;
>>>> +        ti,rx-internal-delay = <DP83867_RGMIIDCTL_2_00_NS>;
>>>> +        ti,fifo-depth = <DP83867_PHYCR_FIFO_DEPTH_4_B_NIB>;
>>>> +    };
>>>> +
>>>> +    icssg2_phy1: ethernet-phy@3 {
>>>> +        reg = <3>;
>>>> +        ti,rx-internal-delay = <DP83867_RGMIIDCTL_2_00_NS>;
>>>> +        ti,fifo-depth = <DP83867_PHYCR_FIFO_DEPTH_4_B_NIB>;
>>>> +    };
>>>> +};
>>

-- 
Thanks and Regards,
Danish