Hi Jason,
I have just send a new series which I hope will supersede this one.
However I will answer on some points:
On 01/01/2014 22:41, Jason Cooper wrote:
> Gregory,
>
> Sorry, but we seem to have a fundamental mis-understanding here. First,
> whatever we end up deciding for the compatible strings needs to be
> documented. Which seems to have not made it into this series.
>
> Second, I'm having trouble explaining this (in my head), so I'm adding
> the DT ml so hopefully someone there can chime in.
>
> AFAICT, the marvell,mv78230-i2c compatible string, added in v3.12, refers
> to the IP block on the A0 revision of the SoC. Since we have set that,
Actually in v3.12 the marvell,mv78230-i2c refer to the B0 revision as I
only worked on it on board using this revision. That's why I proposed
to introduced the marvell,mv78230-a0-i2c compatible string. My concerns was
to not break the existing behavior.
Currently with the marvell,mv78230-i2c compatible string the kernel use
offload on B0 version and hang on A0 version.
If we introduce the marvell,mv78230-a0-i2c compatible string, then the new
kernel with the same dtb will have the same behavior. People using the A0
version are aware that there is a problem (the kernel hang) so they will
be willing to switch to marvell,mv78230-a0-i2c and to change their dtb.
If we introduce the marvell,mv78230-b0-i2c compatible string, then the new
kernel with the same dtb will have different behavior. People using the A0
will have a booting kernel, but I fear that people using B0 revision won't
be aware of the regression.
Gregory
> we've discovered that the A0 revision has an errata where offloading
> doesn't work. The B0 revision of the SoC has fixed offloading for i2c.
>
> In my mind, this means that we should create a fix for the driver to
> disable offloading unless it can determine it's running B0 or newer.
> This is easy once we nail down the compatible strings.
>
> The second thing we need to do is update the binding documentation so
> that the devicetree can describe the hardware accurately. I think we
> should keep 'marvell,mv78230-i2c' as it is (the driver fix mentioned
> above will disable offloading), and add a new compatible
> string, 'marvell,mv78230-b0-i2c'. The driver can then be updated to
> enable offloading when it sees this compatible string, or it can
> determine the SoC revision itself (via mach code).
>
> Third, we need to be able to differentiate between the two shipped
> AX3-4 boards by openblocks. I think this should follow the same pattern
> we decide for the i2c compatible string. So, if we go with my proposal,
> we would have plathome,openblocks-ax3-4 and
> plathome,openblocks-ax3-4-b0.
>
> Basically, I'm really uneasy about dropping marvell,mv78230-i2c and
> essentially re-defining it to marvell,mv78230-a0-i2c. It feels like
> it's breaking backwards compatibility. But I'm having trouble clearly
> describing how Gregory's proposed change exactly does break backwards
> compatibility. Can a DT maintainer explain it more clearly than I?
>
> thx,
>
> Jason.
>
> PS- Well, this ended up being a toppost. Oops. Sorry.
>
> On Tue, Dec 31, 2013 at 05:44:51PM +0100, Gregory CLEMENT wrote:
>> The first variants of Openblocks AX3-4 used the revision A0 of the
>> Armada XP SoCs. These early variants have issues related to the i2c
>> controller which prevent to use the offload mechanism and lead to a
>> kernel hang during boot.
>>
>> The new dts file uses the compatible string marvell,mv78230-a0-i2c for
>> the i2c controller, thanks to this the driver disable the offload
>> mechanism and the kernel no more hangs on these boards.
>>
>> Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
>> ---
>> .../arm/boot/dts/armada-xp-a0-openblocks-ax3-4.dts | 40 +++++
>> .../dts/armada-xp-common-openblocks-ax3-4.dtsi | 177 +++++++++++++++++++++
>> arch/arm/boot/dts/armada-xp-openblocks-ax3-4.dts | 164 +------------------
>> 3 files changed, 218 insertions(+), 163 deletions(-)
>> create mode 100644 arch/arm/boot/dts/armada-xp-a0-openblocks-ax3-4.dts
>> create mode 100644 arch/arm/boot/dts/armada-xp-common-openblocks-ax3-4.dtsi
>>
>> diff --git a/arch/arm/boot/dts/armada-xp-a0-openblocks-ax3-4.dts b/arch/arm/boot/dts/armada-xp-a0-openblocks-ax3-4.dts
>> new file mode 100644
>> index 000000000000..b3ea65255c19
>> --- /dev/null
>> +++ b/arch/arm/boot/dts/armada-xp-a0-openblocks-ax3-4.dts
>> @@ -0,0 +1,40 @@
>> +/*
>> + * Device Tree file for OpenBlocks AX3-4 board with A0 SoC
>> + *
>> + * Copyright (C) 2012 Marvell
>> + *
>> + * Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
>> + *
>> + * This file is licensed under the terms of the GNU General Public
>> + * License version 2. This program is licensed "as is" without any
>> + * warranty of any kind, whether express or implied.
>> + */
>> +
>> +/dts-v1/;
>> +#include "armada-xp-common-openblocks-ax3-4.dtsi"
>> +
>> +/ {
>> + model = "PlatHome OpenBlocks AX3-4 board (A0 SoC)";
>> + compatible = "plathome,openblocks-ax3-4", "marvell,armadaxp-mv78260", "marvell,armadaxp", "marvell,armada-370-xp";
>> +
>> + chosen {
>> + bootargs = "console=ttyS0,115200 earlyprintk";
>> + };
>> +
>> + memory {
>> + device_type = "memory";
>> + reg = <0 0x00000000 0 0xC0000000>; /* 3 GB */
>> + };
>> +
>> + soc {
>> +
>> + internal-regs {
>> + i2c@11000 {
>> + compatible = "marvell,mv78230-a0-i2c", "marvell,mv64xxx-i2c";
>> + };
>> + i2c@11100 {
>> + compatible = "marvell,mv78230-a0-i2c", "marvell,mv64xxx-i2c";
>> + };
>> + };
>> + };
>> +};
>> diff --git a/arch/arm/boot/dts/armada-xp-common-openblocks-ax3-4.dtsi b/arch/arm/boot/dts/armada-xp-common-openblocks-ax3-4.dtsi
>> new file mode 100644
>> index 000000000000..0d452b07baf5
>> --- /dev/null
>> +++ b/arch/arm/boot/dts/armada-xp-common-openblocks-ax3-4.dtsi
>> @@ -0,0 +1,177 @@
>> +/*
>> + * Device Tree file for OpenBlocks AX3-4 board
>> + *
>> + * Copyright (C) 2012 Marvell
>> + *
>> + * Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
>> + *
>> + * This file is licensed under the terms of the GNU General Public
>> + * License version 2. This program is licensed "as is" without any
>> + * warranty of any kind, whether express or implied.
>> + */
>> +
>> +#include "armada-xp-mv78260.dtsi"
>> +
>> +/ {
>> + soc {
>> + ranges = <MBUS_ID(0xf0, 0x01) 0 0 0xd0000000 0x100000
>> + MBUS_ID(0x01, 0x1d) 0 0 0xfff00000 0x100000
>> + MBUS_ID(0x01, 0x2f) 0 0 0xf0000000 0x8000000>;
>> +
>> + devbus-bootcs {
>> + status = "okay";
>> +
>> + /* Device Bus parameters are required */
>> +
>> + /* Read parameters */
>> + devbus,bus-width = <8>;
>> + devbus,turn-off-ps = <60000>;
>> + devbus,badr-skew-ps = <0>;
>> + devbus,acc-first-ps = <124000>;
>> + devbus,acc-next-ps = <248000>;
>> + devbus,rd-setup-ps = <0>;
>> + devbus,rd-hold-ps = <0>;
>> +
>> + /* Write parameters */
>> + devbus,sync-enable = <0>;
>> + devbus,wr-high-ps = <60000>;
>> + devbus,wr-low-ps = <60000>;
>> + devbus,ale-wr-ps = <60000>;
>> +
>> + /* NOR 128 MiB */
>> + nor@0 {
>> + compatible = "cfi-flash";
>> + reg = <0 0x8000000>;
>> + bank-width = <2>;
>> + };
>> + };
>> +
>> + pcie-controller {
>> + status = "okay";
>> + /* Internal mini-PCIe connector */
>> + pcie@1,0 {
>> + /* Port 0, Lane 0 */
>> + status = "okay";
>> + };
>> + };
>> +
>> + internal-regs {
>> + serial@12000 {
>> + clock-frequency = <250000000>;
>> + status = "okay";
>> + };
>> + serial@12100 {
>> + clock-frequency = <250000000>;
>> + status = "okay";
>> + };
>> + pinctrl {
>> + led_pins: led-pins-0 {
>> + marvell,pins = "mpp49", "mpp51", "mpp53";
>> + marvell,function = "gpio";
>> + };
>> + };
>> + leds {
>> + compatible = "gpio-leds";
>> + pinctrl-names = "default";
>> + pinctrl-0 = <&led_pins>;
>> +
>> + red_led {
>> + label = "red_led";
>> + gpios = <&gpio1 17 1>;
>> + default-state = "off";
>> + };
>> +
>> + yellow_led {
>> + label = "yellow_led";
>> + gpios = <&gpio1 19 1>;
>> + default-state = "off";
>> + };
>> +
>> + green_led {
>> + label = "green_led";
>> + gpios = <&gpio1 21 1>;
>> + default-state = "off";
>> + linux,default-trigger = "heartbeat";
>> + };
>> + };
>> +
>> + gpio_keys {
>> + compatible = "gpio-keys";
>> + #address-cells = <1>;
>> + #size-cells = <0>;
>> +
>> + button@1 {
>> + label = "Init Button";
>> + linux,code = <116>;
>> + gpios = <&gpio1 28 0>;
>> + };
>> + };
>> +
>> + mdio {
>> + phy0: ethernet-phy@0 {
>> + reg = <0>;
>> + };
>> +
>> + phy1: ethernet-phy@1 {
>> + reg = <1>;
>> + };
>> +
>> + phy2: ethernet-phy@2 {
>> + reg = <2>;
>> + };
>> +
>> + phy3: ethernet-phy@3 {
>> + reg = <3>;
>> + };
>> + };
>> +
>> + ethernet@70000 {
>> + status = "okay";
>> + phy = <&phy0>;
>> + phy-mode = "sgmii";
>> + };
>> + ethernet@74000 {
>> + status = "okay";
>> + phy = <&phy1>;
>> + phy-mode = "sgmii";
>> + };
>> + ethernet@30000 {
>> + status = "okay";
>> + phy = <&phy2>;
>> + phy-mode = "sgmii";
>> + };
>> + ethernet@34000 {
>> + status = "okay";
>> + phy = <&phy3>;
>> + phy-mode = "sgmii";
>> + };
>> + i2c@11000 {
>> + status = "okay";
>> + clock-frequency = <400000>;
>> + };
>> + i2c@11100 {
>> + status = "okay";
>> + clock-frequency = <400000>;
>> +
>> + s35390a: s35390a@30 {
>> + compatible = "s35390a";
>> + reg = <0x30>;
>> + };
>> + };
>> + sata@a0000 {
>> + nr-ports = <2>;
>> + status = "okay";
>> + };
>> +
>> + /* Front side USB 0 */
>> + usb@50000 {
>> + status = "okay";
>> + };
>> +
>> + /* Front side USB 1 */
>> + usb@51000 {
>> + status = "okay";
>> + };
>> + };
>> + };
>> +};
>> diff --git a/arch/arm/boot/dts/armada-xp-openblocks-ax3-4.dts b/arch/arm/boot/dts/armada-xp-openblocks-ax3-4.dts
>> index 5695afcc04bf..1983de77c3ff 100644
>> --- a/arch/arm/boot/dts/armada-xp-openblocks-ax3-4.dts
>> +++ b/arch/arm/boot/dts/armada-xp-openblocks-ax3-4.dts
>> @@ -11,7 +11,7 @@
>> */
>>
>> /dts-v1/;
>> -#include "armada-xp-mv78260.dtsi"
>> +#include "armada-xp-common-openblocks-ax3-4.dtsi"
>>
>> / {
>> model = "PlatHome OpenBlocks AX3-4 board";
>> @@ -25,166 +25,4 @@
>> device_type = "memory";
>> reg = <0 0x00000000 0 0xC0000000>; /* 3 GB */
>> };
>> -
>> - soc {
>> - ranges = <MBUS_ID(0xf0, 0x01) 0 0 0xd0000000 0x100000
>> - MBUS_ID(0x01, 0x1d) 0 0 0xfff00000 0x100000
>> - MBUS_ID(0x01, 0x2f) 0 0 0xf0000000 0x8000000>;
>> -
>> - devbus-bootcs {
>> - status = "okay";
>> -
>> - /* Device Bus parameters are required */
>> -
>> - /* Read parameters */
>> - devbus,bus-width = <8>;
>> - devbus,turn-off-ps = <60000>;
>> - devbus,badr-skew-ps = <0>;
>> - devbus,acc-first-ps = <124000>;
>> - devbus,acc-next-ps = <248000>;
>> - devbus,rd-setup-ps = <0>;
>> - devbus,rd-hold-ps = <0>;
>> -
>> - /* Write parameters */
>> - devbus,sync-enable = <0>;
>> - devbus,wr-high-ps = <60000>;
>> - devbus,wr-low-ps = <60000>;
>> - devbus,ale-wr-ps = <60000>;
>> -
>> - /* NOR 128 MiB */
>> - nor@0 {
>> - compatible = "cfi-flash";
>> - reg = <0 0x8000000>;
>> - bank-width = <2>;
>> - };
>> - };
>> -
>> - pcie-controller {
>> - status = "okay";
>> - /* Internal mini-PCIe connector */
>> - pcie@1,0 {
>> - /* Port 0, Lane 0 */
>> - status = "okay";
>> - };
>> - };
>> -
>> - internal-regs {
>> - serial@12000 {
>> - clock-frequency = <250000000>;
>> - status = "okay";
>> - };
>> - serial@12100 {
>> - clock-frequency = <250000000>;
>> - status = "okay";
>> - };
>> - pinctrl {
>> - led_pins: led-pins-0 {
>> - marvell,pins = "mpp49", "mpp51", "mpp53";
>> - marvell,function = "gpio";
>> - };
>> - };
>> - leds {
>> - compatible = "gpio-leds";
>> - pinctrl-names = "default";
>> - pinctrl-0 = <&led_pins>;
>> -
>> - red_led {
>> - label = "red_led";
>> - gpios = <&gpio1 17 1>;
>> - default-state = "off";
>> - };
>> -
>> - yellow_led {
>> - label = "yellow_led";
>> - gpios = <&gpio1 19 1>;
>> - default-state = "off";
>> - };
>> -
>> - green_led {
>> - label = "green_led";
>> - gpios = <&gpio1 21 1>;
>> - default-state = "off";
>> - linux,default-trigger = "heartbeat";
>> - };
>> - };
>> -
>> - gpio_keys {
>> - compatible = "gpio-keys";
>> - #address-cells = <1>;
>> - #size-cells = <0>;
>> -
>> - button@1 {
>> - label = "Init Button";
>> - linux,code = <116>;
>> - gpios = <&gpio1 28 0>;
>> - };
>> - };
>> -
>> - mdio {
>> - phy0: ethernet-phy@0 {
>> - reg = <0>;
>> - };
>> -
>> - phy1: ethernet-phy@1 {
>> - reg = <1>;
>> - };
>> -
>> - phy2: ethernet-phy@2 {
>> - reg = <2>;
>> - };
>> -
>> - phy3: ethernet-phy@3 {
>> - reg = <3>;
>> - };
>> - };
>> -
>> - ethernet@70000 {
>> - status = "okay";
>> - phy = <&phy0>;
>> - phy-mode = "sgmii";
>> - };
>> - ethernet@74000 {
>> - status = "okay";
>> - phy = <&phy1>;
>> - phy-mode = "sgmii";
>> - };
>> - ethernet@30000 {
>> - status = "okay";
>> - phy = <&phy2>;
>> - phy-mode = "sgmii";
>> - };
>> - ethernet@34000 {
>> - status = "okay";
>> - phy = <&phy3>;
>> - phy-mode = "sgmii";
>> - };
>> - i2c@11000 {
>> - status = "okay";
>> - clock-frequency = <400000>;
>> - };
>> - i2c@11100 {
>> - status = "okay";
>> - clock-frequency = <400000>;
>> -
>> - s35390a: s35390a@30 {
>> - compatible = "s35390a";
>> - reg = <0x30>;
>> - };
>> - };
>> - sata@a0000 {
>> - nr-ports = <2>;
>> - status = "okay";
>> - };
>> -
>> - /* Front side USB 0 */
>> - usb@50000 {
>> - status = "okay";
>> - };
>> -
>> - /* Front side USB 1 */
>> - usb@51000 {
>> - status = "okay";
>> - };
>> - };
>> - };
>> };
>> --
>> 1.8.1.2
>>
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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