[PATCH 0/3] arm/arm64: Backport DTB support for Raspberry Pi Compute Module 3 to 4.19.y

[PATCH 0/3] arm/arm64: Backport DTB support for Raspberry Pi Compute Module 3 to 4.19.y

[Cyril Brulebois]

The Raspberry Pi Compute Module 3 gathers components that are already
supported in 4.19.y kernels except there's no DTB for it. This small
series of patches backports:
 1. the DTB addition on the arm platform
 2. the extension of this addition to the arm64 platform
 3. the correction of this extension.

I chose to backport patch 2 and 3 separately instead of squashing them
together but I can resubmit with patches 2 and 3 merged if that's
desirable.

This was successfully tested on bare metal, in 64-bit mode, with an
extra patch to the raspi3-firmware packages to get the DTB installed
in the right place, under the right name (bcm2710-rpi-cm3.dtb) so that
the bootloader finds it. The base kernel was 4.19.37-5 as packaged in
Debian.

The summary of changes follows.


Liviu Dudau (1):
  arm64: dts: broadcom: Use the .dtb name in the rule, rather than .dts

Stefan Wahren (2):
  ARM: dts: add Raspberry Pi Compute Module 3 and IO board
  arm64: dts: broadcom: Add reference to Compute Module IO Board V3

 arch/arm/boot/dts/Makefile                         |  1 +
 arch/arm/boot/dts/bcm2837-rpi-cm3-io3.dts          | 87 ++++++++++++++++++++++
 arch/arm/boot/dts/bcm2837-rpi-cm3.dtsi             | 52 +++++++++++++
 arch/arm64/boot/dts/broadcom/Makefile              |  3 +-
 .../boot/dts/broadcom/bcm2837-rpi-cm3-io3.dts      |  2 +
 5 files changed, 144 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm/boot/dts/bcm2837-rpi-cm3-io3.dts
 create mode 100644 arch/arm/boot/dts/bcm2837-rpi-cm3.dtsi
 create mode 100644 arch/arm64/boot/dts/broadcom/bcm2837-rpi-cm3-io3.dts

[PATCH 1/3] ARM: dts: add Raspberry Pi Compute Module 3 and IO board

[Cyril Brulebois]

From: Stefan Wahren <stefan.wahren@i2se.com>

commit a54fe8a6cf66828499b121c3c39c194b43b8ed94 upstream.

The Raspberry Pi Compute Module 3 (CM3) and the Raspberry Pi
Compute Module 3 Lite (CM3L) are SoMs which contains a BCM2837 processor,
1 GB RAM and a GPIO expander. The CM3 has a 4 GB eMMC, but on the CM3L
the eMMC is unpopulated and it's up to the user to connect their
own SD/MMC device. The dtsi file is designed to work for both modules.
There is also a matching carrier board which is called
Compute Module IO Board V3.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Charles Fendt <charles.fendt@me.com>
Signed-off-by: Cyril Brulebois <cyril@debamax.com>
---
 arch/arm/boot/dts/Makefile                |  1 +
 arch/arm/boot/dts/bcm2837-rpi-cm3-io3.dts | 87 +++++++++++++++++++++++++++++++
 arch/arm/boot/dts/bcm2837-rpi-cm3.dtsi    | 52 ++++++++++++++++++
 3 files changed, 140 insertions(+)
 create mode 100644 arch/arm/boot/dts/bcm2837-rpi-cm3-io3.dts
 create mode 100644 arch/arm/boot/dts/bcm2837-rpi-cm3.dtsi

diff --git a/arch/arm/boot/dts/Makefile b/arch/arm/boot/dts/Makefile
index b5bd3de87c33..35c749fe22eb 100644
--- a/arch/arm/boot/dts/Makefile
+++ b/arch/arm/boot/dts/Makefile
@@ -81,6 +81,7 @@ dtb-$(CONFIG_ARCH_BCM2835) += \
 	bcm2836-rpi-2-b.dtb \
 	bcm2837-rpi-3-b.dtb \
 	bcm2837-rpi-3-b-plus.dtb \
+	bcm2837-rpi-cm3-io3.dtb \
 	bcm2835-rpi-zero.dtb \
 	bcm2835-rpi-zero-w.dtb
 dtb-$(CONFIG_ARCH_BCM_5301X) += \
diff --git a/arch/arm/boot/dts/bcm2837-rpi-cm3-io3.dts b/arch/arm/boot/dts/bcm2837-rpi-cm3-io3.dts
new file mode 100644
index 000000000000..6c8233a36d86
--- /dev/null
+++ b/arch/arm/boot/dts/bcm2837-rpi-cm3-io3.dts
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+/dts-v1/;
+#include "bcm2837-rpi-cm3.dtsi"
+#include "bcm283x-rpi-usb-host.dtsi"
+
+/ {
+	compatible = "raspberrypi,3-compute-module", "brcm,bcm2837";
+	model = "Raspberry Pi Compute Module 3 IO board V3.0";
+};
+
+&gpio {
+	/*
+	 * This is based on the official GPU firmware DT blob.
+	 *
+	 * Legend:
+	 * "NC" = not connected (no rail from the SoC)
+	 * "FOO" = GPIO line named "FOO" on the schematic
+	 * "FOO_N" = GPIO line named "FOO" on schematic, active low
+	 */
+	gpio-line-names = "GPIO0",
+			  "GPIO1",
+			  "GPIO2",
+			  "GPIO3",
+			  "GPIO4",
+			  "GPIO5",
+			  "GPIO6",
+			  "GPIO7",
+			  "GPIO8",
+			  "GPIO9",
+			  "GPIO10",
+			  "GPIO11",
+			  "GPIO12",
+			  "GPIO13",
+			  "GPIO14",
+			  "GPIO15",
+			  "GPIO16",
+			  "GPIO17",
+			  "GPIO18",
+			  "GPIO19",
+			  "GPIO20",
+			  "GPIO21",
+			  "GPIO22",
+			  "GPIO23",
+			  "GPIO24",
+			  "GPIO25",
+			  "GPIO26",
+			  "GPIO27",
+			  "GPIO28",
+			  "GPIO29",
+			  "GPIO30",
+			  "GPIO31",
+			  "GPIO32",
+			  "GPIO33",
+			  "GPIO34",
+			  "GPIO35",
+			  "GPIO36",
+			  "GPIO37",
+			  "GPIO38",
+			  "GPIO39",
+			  "GPIO40",
+			  "GPIO41",
+			  "GPIO42",
+			  "GPIO43",
+			  "GPIO44",
+			  "GPIO45",
+			  "GPIO46",
+			  "GPIO47",
+			  /* Used by eMMC */
+			  "SD_CLK_R",
+			  "SD_CMD_R",
+			  "SD_DATA0_R",
+			  "SD_DATA1_R",
+			  "SD_DATA2_R",
+			  "SD_DATA3_R";
+
+	pinctrl-0 = <&gpioout &alt0>;
+};
+
+&hdmi {
+	hpd-gpios = <&expgpio 1 GPIO_ACTIVE_LOW>;
+};
+
+&uart0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&uart0_gpio14>;
+	status = "okay";
+};
diff --git a/arch/arm/boot/dts/bcm2837-rpi-cm3.dtsi b/arch/arm/boot/dts/bcm2837-rpi-cm3.dtsi
new file mode 100644
index 000000000000..7b7ab6aea988
--- /dev/null
+++ b/arch/arm/boot/dts/bcm2837-rpi-cm3.dtsi
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0
+/dts-v1/;
+#include "bcm2837.dtsi"
+#include "bcm2835-rpi.dtsi"
+
+/ {
+	memory {
+		reg = <0 0x40000000>;
+	};
+
+	reg_3v3: fixed-regulator {
+		compatible = "regulator-fixed";
+		regulator-name = "3V3";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		regulator-always-on;
+	};
+
+	reg_1v8: fixed-regulator {
+		compatible = "regulator-fixed";
+		regulator-name = "1V8";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+		regulator-always-on;
+	};
+};
+
+&firmware {
+	expgpio: gpio {
+		compatible = "raspberrypi,firmware-gpio";
+		gpio-controller;
+		#gpio-cells = <2>;
+		gpio-line-names = "HDMI_HPD_N",
+				  "EMMC_EN_N",
+				  "NC",
+				  "NC",
+				  "NC",
+				  "NC",
+				  "NC",
+				  "NC";
+		status = "okay";
+	};
+};
+
+&sdhost {
+	pinctrl-names = "default";
+	pinctrl-0 = <&sdhost_gpio48>;
+	bus-width = <4>;
+	vmmc-supply = <&reg_3v3>;
+	vqmmc-supply = <&reg_1v8>;
+	status = "okay";
+};
-- 
2.11.0

[PATCH 2/3] arm64: dts: broadcom: Add reference to Compute Module IO Board V3

[Cyril Brulebois]

From: Stefan Wahren <stefan.wahren@i2se.com>

commit a7eb26392b893bff92b1eb6483f4af3d2eb19510 upstream.

This adds a reference to the dts of the Compute Module IO Board V3 in arm,
so we don't need to maintain the content in arm64.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Charles Fendt <charles.fendt@me.com>
Signed-off-by: Cyril Brulebois <cyril@debamax.com>
---
 arch/arm64/boot/dts/broadcom/Makefile                | 3 ++-
 arch/arm64/boot/dts/broadcom/bcm2837-rpi-cm3-io3.dts | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm64/boot/dts/broadcom/bcm2837-rpi-cm3-io3.dts

diff --git a/arch/arm64/boot/dts/broadcom/Makefile b/arch/arm64/boot/dts/broadcom/Makefile
index 1193a9e34bbb..3d98f5f5ab88 100644
--- a/arch/arm64/boot/dts/broadcom/Makefile
+++ b/arch/arm64/boot/dts/broadcom/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 dtb-$(CONFIG_ARCH_BCM2835) += bcm2837-rpi-3-b.dtb \
-			      bcm2837-rpi-3-b-plus.dtb
+			      bcm2837-rpi-3-b-plus.dtb \
+			      bcm2837-rpi-cm3-io3.dts
 
 subdir-y	+= northstar2
 subdir-y	+= stingray
diff --git a/arch/arm64/boot/dts/broadcom/bcm2837-rpi-cm3-io3.dts b/arch/arm64/boot/dts/broadcom/bcm2837-rpi-cm3-io3.dts
new file mode 100644
index 000000000000..b1c4ab212c64
--- /dev/null
+++ b/arch/arm64/boot/dts/broadcom/bcm2837-rpi-cm3-io3.dts
@@ -0,0 +1,2 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "arm/bcm2837-rpi-cm3-io3.dts"
-- 
2.11.0

[PATCH 3/3] arm64: dts: broadcom: Use the .dtb name in the rule, rather than .dts

[Cyril Brulebois]

From: Liviu Dudau <liviu@dudau.co.uk>

commit 74cf77e8be35795b4cc57b7010bc348295e421b9 upstream.

Commit a7eb26392b893 ("arm64: dts: broadcom: Add reference to Compute
Module IO Board V3") adds the bcm2837-rpi-cm3-io3.dts file as a target
in the Makefile, rather than the .dtb name. This will skip the
generation of the .dtb file at compile time and will fail the dtbs_install
target.

Fixes: a7eb26392b893 ("arm64: dts: broadcom: Add reference to Compute Module IO Board V3")
Signed-off-by: Liviu Dudau <liviu@dudau.co.uk>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
Tested-by: Charles Fendt <charles.fendt@me.com>
Signed-off-by: Cyril Brulebois <cyril@debamax.com>
---
 arch/arm64/boot/dts/broadcom/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/broadcom/Makefile b/arch/arm64/boot/dts/broadcom/Makefile
index 3d98f5f5ab88..667ca989c11b 100644
--- a/arch/arm64/boot/dts/broadcom/Makefile
+++ b/arch/arm64/boot/dts/broadcom/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 dtb-$(CONFIG_ARCH_BCM2835) += bcm2837-rpi-3-b.dtb \
 			      bcm2837-rpi-3-b-plus.dtb \
-			      bcm2837-rpi-cm3-io3.dts
+			      bcm2837-rpi-cm3-io3.dtb
 
 subdir-y	+= northstar2
 subdir-y	+= stingray
-- 
2.11.0

Re: [PATCH 1/3] ARM: dts: add Raspberry Pi Compute Module 3 and IO board

[Stefan Wahren]

Hi Cyril,

On 15.07.19 16:01, Cyril Brulebois wrote:
> From: Stefan Wahren <stefan.wahren@i2se.com>
>
> commit a54fe8a6cf66828499b121c3c39c194b43b8ed94 upstream.
>
> The Raspberry Pi Compute Module 3 (CM3) and the Raspberry Pi
> Compute Module 3 Lite (CM3L) are SoMs which contains a BCM2837 processor,
> 1 GB RAM and a GPIO expander. The CM3 has a 4 GB eMMC, but on the CM3L
> the eMMC is unpopulated and it's up to the user to connect their
> own SD/MMC device. The dtsi file is designed to work for both modules.
> There is also a matching carrier board which is called
> Compute Module IO Board V3.

this patch series doesn't apply to the stable kernel rules.

Regards
Stefan

Re: [PATCH 1/3] ARM: dts: add Raspberry Pi Compute Module 3 and IO board

[Greg KH]

On Mon, Jul 15, 2019 at 05:26:16PM +0200, Stefan Wahren wrote:
> Hi Cyril,
> 
> On 15.07.19 16:01, Cyril Brulebois wrote:
> > From: Stefan Wahren <stefan.wahren@i2se.com>
> >
> > commit a54fe8a6cf66828499b121c3c39c194b43b8ed94 upstream.
> >
> > The Raspberry Pi Compute Module 3 (CM3) and the Raspberry Pi
> > Compute Module 3 Lite (CM3L) are SoMs which contains a BCM2837 processor,
> > 1 GB RAM and a GPIO expander. The CM3 has a 4 GB eMMC, but on the CM3L
> > the eMMC is unpopulated and it's up to the user to connect their
> > own SD/MMC device. The dtsi file is designed to work for both modules.
> > There is also a matching carrier board which is called
> > Compute Module IO Board V3.
> 
> this patch series doesn't apply to the stable kernel rules.

I'm with Stefan.  Cyril, how do you think this matches up with what:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
says?

thanks,

greg k-h

Re: [PATCH 1/3] ARM: dts: add Raspberry Pi Compute Module 3 and IO board

[Cyril Brulebois]

Hi Greg, Stefan,

Greg KH <greg@kroah.com> (2019-07-16):
> On Mon, Jul 15, 2019 at 05:26:16PM +0200, Stefan Wahren wrote:
> > Hi Cyril,
> > 
> > On 15.07.19 16:01, Cyril Brulebois wrote:
> > > From: Stefan Wahren <stefan.wahren@i2se.com>
> > >
> > > commit a54fe8a6cf66828499b121c3c39c194b43b8ed94 upstream.
> > >
> > > The Raspberry Pi Compute Module 3 (CM3) and the Raspberry Pi
> > > Compute Module 3 Lite (CM3L) are SoMs which contains a BCM2837 processor,
> > > 1 GB RAM and a GPIO expander. The CM3 has a 4 GB eMMC, but on the CM3L
> > > the eMMC is unpopulated and it's up to the user to connect their
> > > own SD/MMC device. The dtsi file is designed to work for both modules.
> > > There is also a matching carrier board which is called
> > > Compute Module IO Board V3.
> > 
> > this patch series doesn't apply to the stable kernel rules.
> 
> I'm with Stefan.  Cyril, how do you think this matches up with what:
>     https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> says?

First off, I'm sorry to have wasted everyone's time with this attempt at
getting the DTB addition upstream'd so that other distributions/users
could benefit from it as well; it's now been included downstream
instead.


stable-kernel-rules has this entry that made me think this would be
acceptable:

    - New device IDs and quirks are also accepted.

To my non-expert eyes, a DTB looked similar to a bunch of device IDs,
mapping specific hardware to the right modules and parameters. I thought
that allowing device IDs to be added, mapping new HW to existing and
known-to-be-working modules, was similar to what's happening with a DTB.


In hindsight, looking at say 4.9 or 4.19 (baselines for Debian kernels),
I see that DTBs were fixed but never added. Maybe having an extra “(DTBs
don't qualify)” in the documentation might prevent others from making
the same mistake?


Cheers,
-- 
Cyril Brulebois -- Debian Consultant @ DEBAMAX -- https://debamax.com/

Re: [PATCH 1/3] ARM: dts: add Raspberry Pi Compute Module 3 and IO board

[Greg KH]

On Wed, Jul 17, 2019 at 04:04:59AM +0200, Cyril Brulebois wrote:
> Hi Greg, Stefan,
> 
> Greg KH <greg@kroah.com> (2019-07-16):
> > On Mon, Jul 15, 2019 at 05:26:16PM +0200, Stefan Wahren wrote:
> > > Hi Cyril,
> > > 
> > > On 15.07.19 16:01, Cyril Brulebois wrote:
> > > > From: Stefan Wahren <stefan.wahren@i2se.com>
> > > >
> > > > commit a54fe8a6cf66828499b121c3c39c194b43b8ed94 upstream.
> > > >
> > > > The Raspberry Pi Compute Module 3 (CM3) and the Raspberry Pi
> > > > Compute Module 3 Lite (CM3L) are SoMs which contains a BCM2837 processor,
> > > > 1 GB RAM and a GPIO expander. The CM3 has a 4 GB eMMC, but on the CM3L
> > > > the eMMC is unpopulated and it's up to the user to connect their
> > > > own SD/MMC device. The dtsi file is designed to work for both modules.
> > > > There is also a matching carrier board which is called
> > > > Compute Module IO Board V3.
> > > 
> > > this patch series doesn't apply to the stable kernel rules.
> > 
> > I'm with Stefan.  Cyril, how do you think this matches up with what:
> >     https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> > says?
> 
> First off, I'm sorry to have wasted everyone's time with this attempt at
> getting the DTB addition upstream'd so that other distributions/users
> could benefit from it as well; it's now been included downstream
> instead.
> 
> 
> stable-kernel-rules has this entry that made me think this would be
> acceptable:
> 
>     - New device IDs and quirks are also accepted.
> 
> To my non-expert eyes, a DTB looked similar to a bunch of device IDs,
> mapping specific hardware to the right modules and parameters. I thought
> that allowing device IDs to be added, mapping new HW to existing and
> known-to-be-working modules, was similar to what's happening with a DTB.
> 
> 
> In hindsight, looking at say 4.9 or 4.19 (baselines for Debian kernels),
> I see that DTBs were fixed but never added. Maybe having an extra “(DTBs
> don't qualify)” in the documentation might prevent others from making
> the same mistake?

I don't think that anyone has made that same mistake in the past 5+
years that I can recall at the moment, so adding more text to the file
probably will not really save us many issues like this :)

thanks,

greg k-h