[RFC PATCH 0/3] Fix i2c bus hang on A0 version of the Armada XP SoCs

[RFC PATCH 0/3] Fix i2c bus hang on A0 version of the Armada XP SoCs

[Gregory CLEMENT]

Hi,

This series is an RFC to fix the i2c bus hang on A0 version of the
Armada XP SoCs. It occured on the the eraly release of the OpenBlocks
AX3-4 bords. Indeed the first variants of Armada XP SoCs (A0 stepping)
have issues related to the i2c controller which prevent to use the
offload mechanism and lead to a kernel hang during boot.

The best solution will be to detect the SoCs version at runtime and
use it in the driver, but I chosed to submit this version in case CPU
version detection feature takes more time than expected (and we
already reached the rc6 kernel).

Thanks,

Gregory


Gregory CLEMENT (3):
  arm: mvebu: add new dts file for old variant of Openblocks AX3-4
  i2c: mv64xxx: Fix bus hang on A0 version of the Armada XP SoCs
  i2c: mv64xxx: Document the newly introduced Armada XP A0 compatible

 .../devicetree/bindings/i2c/i2c-mv64xxx.txt        |   2 +-
 .../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 +------------------
 drivers/i2c/busses/i2c-mv64xxx.c                   |   8 +
 5 files changed, 227 insertions(+), 164 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

-- 
1.8.1.2

[RFC PATCH 1/3] arm: mvebu: add new dts file for old variant of Openblocks AX3-4

[Gregory CLEMENT]

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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
---
 .../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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
+ *
+ * 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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
+ *
+ * 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

Re: [RFC PATCH 1/3] arm: mvebu: add new dts file for old variant of Openblocks AX3-4

[Jason Cooper]

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,
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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> ---
>  .../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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> + *
> + * 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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> + *
> + * 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
> 

Re: [RFC PATCH 1/3] arm: mvebu: add new dts file for old variant of Openblocks AX3-4

[Jason Cooper]

On Wed, Jan 01, 2014 at 04:41:16PM -0500, Jason Cooper wrote:
> 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.

Ok, this is taken care of in the last patch of the series...  Sorry
about the noise.

thx,

Jason.

Re: [RFC PATCH 1/3] arm: mvebu: add new dts file for old variant of Openblocks AX3-4

[Gregory CLEMENT]

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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
>> ---
>>  .../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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
>> + *
>> + * 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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
>> + *
>> + * 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

[RFC PATCH 2/3] i2c: mv64xxx: Fix bus hang on A0 version of the Armada XP SoCs

[Gregory CLEMENT]

The first variants of Armada XP SoCs (A0 stepping) have issues related
to the i2c controller which prevent to use the offload mechanism and
lead to a kernel hang during boot.

The commit introduces a new the compatible string
marvell,mv78230-a0-i2c for the i2c controller. When this compatible
string is used the driver disables the offload mechanism and the
kernel no more hangs on these SoCs.

Signed-off-by: Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
---
 drivers/i2c/busses/i2c-mv64xxx.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 8be7e42aa4de..f424c0f89946 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -692,6 +692,10 @@ static const struct of_device_id mv64xxx_i2c_of_match_table[] = {
 	{ .compatible = "allwinner,sun4i-i2c", .data = &mv64xxx_i2c_regs_sun4i},
 	{ .compatible = "marvell,mv64xxx-i2c", .data = &mv64xxx_i2c_regs_mv64xxx},
 	{ .compatible = "marvell,mv78230-i2c", .data = &mv64xxx_i2c_regs_mv64xxx},
+	{
+		.compatible = "marvell,mv78230-a0-i2c",
+		.data = &mv64xxx_i2c_regs_mv64xxx
+	},
 	{}
 };
 MODULE_DEVICE_TABLE(of, mv64xxx_i2c_of_match_table);
@@ -783,6 +787,10 @@ mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data,
 		drv_data->errata_delay = true;
 	}
 
+	if (of_device_is_compatible(np, "marvell,mv78230-a0-i2c")) {
+		drv_data->offload_enabled = false;
+		drv_data->errata_delay = true;
+	}
 out:
 	return rc;
 #endif
-- 
1.8.1.2

[RFC PATCH 3/3] i2c: mv64xxx: Document the newly introduced Armada XP A0 compatible

[Gregory CLEMENT]

Signed-off-by: Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
---
 Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
index 82e8f6f17179..9410ed72ec45 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
@@ -5,7 +5,7 @@ Required properties :
 
  - reg             : Offset and length of the register set for the device
  - compatible      : Should be "marvell,mv64xxx-i2c" or "allwinner,sun4i-i2c"
-                     or "marvell,mv78230-i2c"
+                     or "marvell,mv78230-i2c" or "marvell,mv78230-a0-i2c"
  - interrupts      : The interrupt number
 
 Optional properties :
-- 
1.8.1.2

Re: [RFC PATCH 3/3] i2c: mv64xxx: Document the newly introduced Armada XP A0 compatible

[Jason Cooper]

On Tue, Dec 31, 2013 at 05:44:53PM +0100, Gregory CLEMENT wrote:
> Signed-off-by: Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> ---
>  Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
> index 82e8f6f17179..9410ed72ec45 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
> @@ -5,7 +5,7 @@ Required properties :
>  
>   - reg             : Offset and length of the register set for the device
>   - compatible      : Should be "marvell,mv64xxx-i2c" or "allwinner,sun4i-i2c"
> -                     or "marvell,mv78230-i2c"
> +                     or "marvell,mv78230-i2c" or "marvell,mv78230-a0-i2c"

Once we nail down how we want to do this, Please add an explanation of
the differences between the compatibles.  eg 'offloading broken'.

thx,

Jason.

>   - interrupts      : The interrupt number
>  
>  Optional properties :
> -- 
> 1.8.1.2
> 

Re: [RFC PATCH 3/3] i2c: mv64xxx: Document the newly introduced Armada XP A0 compatible

[Jason Cooper]

[+ DT ml, Grant, Rob]

On Tue, Dec 31, 2013 at 05:44:53PM +0100, Gregory CLEMENT wrote:
> Signed-off-by: Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> ---
>  Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
> index 82e8f6f17179..9410ed72ec45 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
> @@ -5,7 +5,7 @@ Required properties :
>  
>   - reg             : Offset and length of the register set for the device
>   - compatible      : Should be "marvell,mv64xxx-i2c" or "allwinner,sun4i-i2c"
> -                     or "marvell,mv78230-i2c"
> +                     or "marvell,mv78230-i2c" or "marvell,mv78230-a0-i2c"

Once we nail down how we want to do this, Please add an explanation of
the differences between the compatibles.  eg 'offloading broken'.

thx,

Jason.

>   - interrupts      : The interrupt number
>  
>  Optional properties :
> -- 
> 1.8.1.2
> 

Re: [RFC PATCH 3/3] i2c: mv64xxx: Document the newly introduced Armada XP A0 compatible

[Gregory CLEMENT]

On 01/01/2014 22:45, Jason Cooper wrote:
> [+ DT ml, Grant, Rob]
> 
> On Tue, Dec 31, 2013 at 05:44:53PM +0100, Gregory CLEMENT wrote:
>> Signed-off-by: Gregory CLEMENT <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
>> ---
>>  Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
>> index 82e8f6f17179..9410ed72ec45 100644
>> --- a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
>> +++ b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
>> @@ -5,7 +5,7 @@ Required properties :
>>  
>>   - reg             : Offset and length of the register set for the device
>>   - compatible      : Should be "marvell,mv64xxx-i2c" or "allwinner,sun4i-i2c"
>> -                     or "marvell,mv78230-i2c"
>> +                     or "marvell,mv78230-i2c" or "marvell,mv78230-a0-i2c"
> 
> Once we nail down how we want to do this, Please add an explanation of
> the differences between the compatibles.  eg 'offloading broken'.
> 

Just to keep the DT mailing list, Grant and Rob in touch: I have
submitted an other series in which we don't have to use the device
tree to know the SoC revision. So if everything turns well we won't
have to apply this series.

If at the end we still need it, then I will add the explanation in
the next version.


Gregory

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

Re: [RFC PATCH 0/3] Fix i2c bus hang on A0 version of the Armada XP SoCs

[Andrew Lunn]

On Tue, Dec 31, 2013 at 05:44:50PM +0100, Gregory CLEMENT wrote:
> Hi,
> 
> This series is an RFC to fix the i2c bus hang on A0 version of the
> Armada XP SoCs. It occured on the the eraly release of the OpenBlocks
> AX3-4 bords. Indeed the first variants of Armada XP SoCs (A0 stepping)
> have issues related to the i2c controller which prevent to use the
> offload mechanism and lead to a kernel hang during boot.
> 
> The best solution will be to detect the SoCs version at runtime and
> use it in the driver, but I chosed to submit this version in case CPU
> version detection feature takes more time than expected (and we
> already reached the rc6 kernel).
> 
> Thanks,
> 
> Gregory

Hi Gregory

Thanks for these RFC patches. I can confirm they work on my Openblocks
device with an A0 stepping SoC. I can now access the RTC.

You missed adding the new DTS file to the Makefile. Depending on how
the discussion goes about auto detecting stepping or not, i would of
used different filenames, probably:

armada-xp-openblocks-ax3-4.dts
armada-xp-openblocks-ax3-4-a0.dts
armada-xp-openblocks-ax3-4-common.dts

Keeps all the files together when listed alphabetically

Thanks
	Andrew

Re: [RFC PATCH 0/3] Fix i2c bus hang on A0 version of the Armada XP SoCs

[Gregory CLEMENT]

Hi Andrew,

On 01/01/2014 20:28, Andrew Lunn wrote:
> On Tue, Dec 31, 2013 at 05:44:50PM +0100, Gregory CLEMENT wrote:
>> Hi,
>>
>> This series is an RFC to fix the i2c bus hang on A0 version of the
>> Armada XP SoCs. It occured on the the eraly release of the OpenBlocks
>> AX3-4 bords. Indeed the first variants of Armada XP SoCs (A0 stepping)
>> have issues related to the i2c controller which prevent to use the
>> offload mechanism and lead to a kernel hang during boot.
>>
>> The best solution will be to detect the SoCs version at runtime and
>> use it in the driver, but I chosed to submit this version in case CPU
>> version detection feature takes more time than expected (and we
>> already reached the rc6 kernel).
>>
>> Thanks,
>>
>> Gregory
> 
> Hi Gregory
> 
> Thanks for these RFC patches. I can confirm they work on my Openblocks
> device with an A0 stepping SoC. I can now access the RTC.
> 
> You missed adding the new DTS file to the Makefile. Depending on how
> the discussion goes about auto detecting stepping or not, i would of
> used different filenames, probably:

Thanks for your feedback. In case there will be a second version I will
take them into account. However I hope we won't need it as I sent a
new series to fix this bug by dynamically getting the SoC revision.

> 
> armada-xp-openblocks-ax3-4.dts
> armada-xp-openblocks-ax3-4-a0.dts
> armada-xp-openblocks-ax3-4-common.dts

you probably meant armada-xp-openblocks-ax3-4-common.dtsi, but I got the
point and I agree.

> 
> Keeps all the files together when listed alphabetically
> 


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